Scientific publications—2012

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Each year, CRC's researchers author a number of publications communicating successes in advanced wireless telecommunications R&D. Integral to their work is sharing the results with others.

Here you will find abstracts and links to papers published in peer-reviewed scientific journals or books or presented at conference proceedings.

If you experience issues accessing the full report or the website, please contact us. Other formats of documents are also available upon request.


Research publications—2012
Title Authors
Broadside Radiation by Excitation of EBG Leaky Mode

Year: 2012

Abstract: A broadside radiation from an electromagnetic band-gap (EBG) waveguide is achieved. The EBG waveguide, which operates around 30 GHz, is designed using a square lattice of metal vias to build a spatial power combiner. A surface mode was excited by adding a row of holes to the square lattice of metal vias. The row of holes was modulated to couple the surface mode to a leaky mode that radiates in free space. The return loss of the optimized structure is less than -10 dB around a frequency of 30 GHz, and the radiation pattern has the main beam along the broadside. The measured data of the fabricated structure confirm the directional radiation pattern.

Source title: IEEE Antennas and Wireless Propagation Letters

DOI: 10.1109/LAWP.2012.2207942

Link: Broadside Radiation by Excitation of EBG Leaky Mode

Abdo, M. R.; Chaharmir, J.; Shaker, Y.; Antar, Y.M.M.
Derivation and validation of the basic design equations for symmetric sub-reflectarrays

Year: 2012

Abstract: The basic design equations for symmetrical sub-reflectarrays are derived. These provide the required phase-distribution on the sub-reflectarray surface. Both ellipsoidal-type and hyperboloidal-type sub-reflectarrays are designed and fabricated using single-layer rectangular patch elements. Measured amplitude and phase patterns are shown for both types of sub-reflectarray, and compared to predictions. The behaviour of the ellipsoidal-type sub-reflectarray is furthermore compared to measured patterns of its solid subreflector counterpart. These experimental results show that the sub-reflectarrays indeed emulate the behaviour of their solid subreflector counterparts, and the validity of the basic design equations is thus established. © 2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 60 Issue 5

DOI: 10.1109/TAP.2012.2189694

Link: Derivation and validation of the basic design equations for symmetric sub-reflectarrays

Almajali, E.; McNamara, D.; Shaker, J.; Chaharmir, M.R.
An investigation of reflectarray operation using its component current contributions

Year: 2012

Abstract: Reflectarray operation is described by examining the contributions of its different components (the conducting patches, groundplane and dielectric substrate) to its far- and near-fields. It is shown how the fields, computed from a very complete full-wave model using the high-frequency structure simulator HFSS, can be separately post-processed to find the appropriate currents (not routinely available from HFSS) on the individual reflectarray components. The far- and near-field contributions of these currents are then used to assess the role played by these individual components in the overall reflectarray operation. © 2012 IEEE.

Source title: Proceedings of 6th European Conference on Antennas and Propagation, EuCAP 2012

DOI: 10.1109/EuCAP.2012.6206022

Link: An investigation of reflectarray operation using its component current contributions

Almajali, E.; McNamara, D.A.; Shaker, J.; Chaharmir, M.R.
On beam squint in offset-fed reflectarrays

Year: 2012

Abstract: A full-wave receive-mode analysis is used to show that it is the shift in the location of the focal point with frequency (caused by nonconstant path delays over the surface of the reflectarray) that is principally responsible for the beam squint that occurs in offset-fed reflectarray antennas, and not the element type used or the lattice size. A similar transmit-mode analysis confirms that it is this focal point shift that implies noncoincidence of the focal point and the feed phase center at off-center frequencies, which results in a phase distribution over the reflectarray aperture with a slope other than that required to have the main beam in the desired direction. We further demonstrate this fact (computationally and experimentally) by showing that if the feed is physically moved to the shifted focal point at some off-center frequency, the main beam pointing direction at this frequency is restored. © 2011 IEEE.

Source title: IEEE Antennas and Wireless Propagation Letters

Series Number: Volume 11

DOI: 10.1109/LAWP.2012.2212171

Link: On beam squint in offset-fed reflectarrays

Almajali, E.; McNamara, D.A.; Shaker, J.; Chaharmir, M.R.
Assessment of Radiometeorological Parameters Used in the Development of Maps of Propagation Impairments and Path Availability for Canada at 40/50 GHz

Year: 2012

Abstract: Examination of radiometeorological parameters used for the production of maps of attenuation due to the atmosphere at 40 and 50 GHz for links to a geostationary satellite.

Source title: 30th AIAA International Communications Satellite Systems Conference (ICSSC) Conference

DOI: 10.2514/6.2012-15239

Link: Assessment of Radiometeorological Parameters Used in the Development of Maps of Propagation Impairments and Path Availability for Canada at 40/50 GHz

Amaya, C.; Bouchard, P.; Nguyen, T.
Empirical evaluation of the impact of wind turbines on dvb-t reception quality

Year: 2012

Abstract: This Conference Paper/Presentation describes the results of two extensive measurement campaigns for evaluating the potential impact of scattered signals from wind turbines on terrestrial DTV reception quality in the UHF band. A detailed description of the different propagation channels encountered is provided. Furthermore, empirical threshold carrier-to-noise requirements for Quasi Error Free reception in the DVB-T system in the area of influence of a wind farm are presented, and the situations where a significant degradation can be found are identified and characterized. © 2011 IEEE.

Source title: IEEE Transactions on Broadcasting

Series Number: Volume 58 Issue 1

DOI: 10.1109/TBC.2011.2173818

Link: Empirical evaluation of the impact of wind turbines on dvb-t reception quality

Angulo, I.; De La Vega, D.; Grande, O.; Cau, N.; Gil, U.; Wu, Y.; Guerra, D.; Angueira, P.
Distributed Clustering of Cognitive Radio Networks: A Message-Passing Approach

Year: 2012

Abstract: This publication reviews techniques designed for cluster formation in decentralized wireless networks and discusses a distributed technique suitable for dynamic spectrum access systems. Case studies are used to demonstrate that the approach enables collaborative network functions such as resource management and spectrum sensing to be addressed more efficiently.

Source title: Cognitive Communications: Distributed Artificial Intelligence (DAI), Regulatory Policy & Economics, Implementation

DOI: 10.1002/9781118360316.ch5

Link: Distributed Clustering of Cognitive Radio Networks: A Message-Passing Approach

Baddour, K.E.; Ureten,O.; Willink, T.J.
Single-shot and real-time self-referenced phase characterization of GHz-rate QPSK signals

Year: 2012

Abstract: Phase Reconstruction using Optical Ultrafast Differentiation (PROUD) is implemented in an integrated-waveguide format, demonstrating self-referenced phase characterization of GHz-rate Quadratic Phase-Shift Keying (QPSK) signals in a single-shot and in real-time. © 2012 OSA.

Source title: Optics InfoBase Conference Paper/Presentations, Signal Processing in Photonic Communications, SPPCOM 2012;

DOI: 10.1364/SPPCOM.2012.SpTu4A.3

Link: Single-shot and real-time self-referenced phase characterization of GHz-rate QPSK signals

Bazargani, H.P.; Quelene, J.-B.; Dumais, P.; Callender, C.L.; Malacarne, A.; Azana, J.
Joint optimization of bit and power allocation for multicarrier systems with average BER constraint

Year: 2012

Abstract: This paper proposes a novel joint bit and power allocation algorithm for multicarrier systems operating in fading environments. The algorithm jointly maximizes the throughput and minimizes the transmitted power, while guaranteeing a target average bit error rate (BER). Simulation results are described and they illustrate the performance of the proposed scheme and demonstrate its superiority with respect to existing schemes. © 2012 IEEE.

Source title: IEEE Vehicular Technology Conference

DOI: 10.1109/VTCFall.2012.6399158

Link: Joint optimization of bit and power allocation for multicarrier systems with average BER constraint

Bedeer, E.; Dobre, O.A.; Ahmed, M.H.; Baddour, K.E.
Optimal bit and power loading for OFDM systems with average BER and total power constraints

Year: 2012

Abstract: In this paper, a novel joint bit and power loading algorithm is proposed for orthogonal frequency division multiplexing (OFDM) systems operating in fading environments. The algorithm jointly maximizes the throughput and minimizes the transmitted power, while guaranteeing a target average bit error rate (BER) and meeting a constraint on the total transmit power. Simulation results are described that illustrate the performance of the proposed scheme and demonstrate its superiority when compared to the algorithm in [1]. © 2012 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2012.6503689

Link: Optimal bit and power loading for OFDM systems with average BER and total power constraints

Bedeer, E.; Dobre, O.A.; Ahmed, M.H.; Baddour, K.E.
Adaptive bit allocation for OFDM cognitive radio systems with imperfect channel estimation

Year: 2012

Abstract: Cognitive radios hold tremendous promise for increasing the spectral efficiency of wireless communication systems. In this paper, an adaptive bit allocation algorithm is presented for orthogonal frequency division multiplexing (OFDM) CR systems operating in a frequency selective fading environment. The algorithm maximizes the CR system throughput in the presence of narrowband interference, while guaranteeing a BER below a predefined threshold. The effect of imperfect channel estimation on the algorithm's performance is also studied. © 2012 IEEE.

Source title:

DOI: 10.1109/RWS.2012.6175359

Link: Adaptive bit allocation for OFDM cognitive radio systems with imperfect channel estimation

Bedeer, E.; Marey, M.; Dobre, O.; Baddour, K.
A novel algorithm for joint bit and power loading for OFDM systems with unknown interference

Year: 2012

Abstract: In this paper, a novel low complexity bit and power loading algorithm is formulated for orthogonal frequency division multiplexing (OFDM) systems operating in fading environments and in the presence of unknown interference. The proposed non-iterative algorithm jointly maximizes the throughput and minimizes the transmitted power, while guaranteeing a target bit error rate (BER) per subcarrier. Closed-form expressions are derived for the optimal bit and power distributions per subcarrier. The performance of the proposed algorithm is investigated through extensive simulations. A performance comparison with the algorithm shows the superiority of the proposed algorithm with reduced computational effort. © 2012 IEEE.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2012.6363834

Link: A novel algorithm for joint bit and power loading for OFDM systems with unknown interference

Bedeer, E.; Marey, M.F.; Dobre, O.A.; Ahmed, M.H.; Baddour, K.E.
A fessenden Christmas Eve broadcast retrospective

Year: 2012

Abstract: Reginald Aubrey Fessenden made the world's fi rst wireless broadcast on Christmas Eve, 1906. It was indeed a "broadcast", and not just a station-to-station demonstration, as was his December 21, 1906, major demonstration. Three days before Christmas Eve, 1906, Brant Rock Station staff notified (by wireless telegraphy) ships of the US Navy and the United Fruit Company to listen for special broadcasts on Christmas' and New Year's Eves. These ships had previously been fitted with Fessenden radio receivers, and so they were able to receive AM radio broadcast transmissions. "Special" applied, since the broadcast was a prepared program of voice and music for the holiday season. After wishing all listeners a "Merry Christmas", Fessenden added: "Will all those who heard these words and music please write to R. A. Fessenden at Brant Rock, MA." His concluding remark was, "We will speak to you again on New Year's Eve." We are told letters reporting reception of the broadcast were received, but today none can be found. We can also read that astonished wireless operators sent reception reports at the time, by wireless tele graphy. © 2011 IEEE.

Source title: IEEE Antennas and Propagation Magazine

Series Number: Volume 54 Issue 4

DOI: 10.1109/MAP.2012.6309206

Link: A fessenden christmas eve broadcast retrospective

Belrose, J.S.
Experimental characterization of MIMO-UWB multipath underground mine radio channels

Year: 2012

Abstract: This Conference Paper/Presentation reports on experimental results and its interpretations for MIMO-UWB multipath channel. It is intended to help in establishing design guidelines for underground mine wireless communications systems using MIMO-UWB technology. It deals with measurements obtained using two different antenna configurations under line-of-sight (LOS) conditions. Furthermore, the MIMO channel is characterized in terms of channel correlation and capacity. It was shown that a special arrangement of antennas in a MIMO system may reduce channel correlation and improve capacity. © 2012 IEEE.

Source title: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest)

DOI: 10.1109/APS.2012.6348622

Link: Experimental characterization of MIMO-UWB multipath underground mine radio channels

Ben, Mabrouk I.; Talbi, L.; Nedil, M.; Hettak, K.
Laboratory performance assessment for DRM+ system in single and dual-antenna transmission scenarios

Year: 2012

Abstract: It has been shown that due to its smaller signal bandwidth (96 KHz), DRM+ signal could suffer from flat fading degradation at low receiver speeds, particularly in urban environments. To alleviate this problem, a simple transmit delay diversity (TDD) has been proposed in the standard. This Conference Paper/Presentation tries to investigate this issue by presenting the performance results of multipath fading characterizations performed in the laboratory for DRM+ system. Both single and dual-antenna transmission scenarios have been considered. By using a sophisticated hardware channel simulator, different radio channel models corresponding to various scenarios and environments (urban, suburban, mountain, SFN, etc) could be tested and compared. For a single antenna scenario, the results show that indeed, at low receiver speeds (5 km/h), the DRM+ receiver was unable to cope with the effect of flat fading in the urban channel model. However, in the same environment, TDD scheme provides 3 dB gain over single antenna transmission if low or moderate correlation level is maintained between the two signal paths. Moreover, it has been found that for a TDD enhanced DRM+ system, a better performance is obtained with the SFN channel model as compared to urban and rural channels when the two signals are highly correlated. © 2012 IEEE.

Source title: IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, BMSB

DOI: 10.1109/BMSB.2012.6264253

Link: Laboratory performance assessment for DRM+ system in single and dual-antenna transmission scenarios

Benani, A.M.; Quenneville, M.
Signal recovery for CPM in frequency flat fast fading channels

Year: 2012

Abstract: A channel estimation scheme applicable to nonlinear modulation over frequency flat fast fading channels is presented. It is shown that the use of local B-splines for channel estimation results in excellent error rate performance and also low complexity compared to more traditional approaches. © 2012 IEEE.

Source title: IEEE Military Communications Conference MILCOM

DOI: 10.1109/MILCOM.2012.6415661

Link: Signal recovery for CPM in frequency flat fast fading channels

Brown, C.; Vigneron, P.J.
MAC performance improvement in UAV ad-hoc networks with full-duplex radios and multi-packet reception capability

Year: 2012

Abstract: Recent advances in interference cancellation and signal processing techniques can enable full-duplex radios and multi-packet reception (MPR) capability, which will have significant impacts on the medium access control (MAC) design. In this Conference Paper/Presentation, we study the MAC design in UAV ad-hoc networks with full-duplex radios and MPR. To efficiently handle the highly mobile environment of a UAV ad-hoc network, a token-based technique is used for updating information in the network. The MAC scheme in the presence of perfect and imperfect channel state information are formulated as a combinatorial optimization problem and a discrete stochastic optimization problem, respectively. Simulation results are presented to show the effectiveness of the proposed MAC. © 2012 IEEE.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2012.6364116

Link: MAC performance improvement in UAV ad-hoc networks with full-duplex radios and multi-packet reception capability

Cai, Y.; Yu, F.R.; Li, J.; Zhou, Y.; Lamont, L.
Distributed scheduling for unmanned aerial vehicle networks with full-duplex radios and multi-packet reception

Year: 2012

Abstract: Applications of unmanned aerial vehicle (UAV) ad-hoc networks have raised challenges in the design of distributed scheduling schemes since those applications require stringent quality of service (QoS) in complicated environments. Most existing scheduling designs for UAV ad-hoc networks are based on traditional physical layer techniques, such as half-duplex radios without multi-packet reception capability. However, recent advances in interference cancellation and signal processing techniques can enable full-duplex radios (FDR) and multi-packet reception (MPR) capability, which will have significant impacts on the design of link layer algorithm, especially scheduling. In this Conference Paper/Presentation, we study the distributed scheduling issue in UAV ad-hoc networks with FDRs andMPR capability. The distributed scheduling problem in the presence of perfect and imperfect channel state information are formulated as a combinatorial optimization problem and a discrete stochastic optimization problem, respectively. Simulation results show that physical layer FDR andMPR capability have significant impacts on the performance of UAV ad-hoc networks. We also investigate the convergence property of proposed scheme and the effect of channel estimation errors. Copyright 2012 ACM.

Source title: DIVANet'12 - Proceedings of the ACM Workshop on Design and Analysis of Intelligent Vehicular Networks and Applications

DOI: 10.1145/2386958.2386972

Link: Distributed scheduling for unmanned aerial vehicle networks with full-duplex radios and multi-packet reception

Cai, Y.; Yu, F.R.; Li, J.; Zhou, Y.; Lamont, L.
Compact silica-on-silicon planar lightwave circuits for high speed optical signal processing

Year: 2012

Abstract: Silica-on-silicon planar lightwave circuit (PLC) technology is well established and provides a low loss and stable photonic device platform. However, limitations in size and integration of active components remain. Engineering of the layer structure in silica PLCs to achieve high-index contrast, compact device architectures and monolithically integrated optical nonlinearities is described. Modeling of properties of doped-silica layers provides a design strategy for optimization of waveguide loss and birefringence. Optical nonlinearities in poled silica layers have been demonstrated, and recent work to incorporate these into functional device structures and exploit them for high speed modulation is reported. © 2012 SPIE.

Source title: Proceedings of SPIE - The International Society for Optical Engineering

Series Number: Volume 8257

DOI: 10.1117/12.907443

Link: Compact silica-on-silicon planar lightwave circuits for high speed optical signal processing

Callender, C.L.; Dumais, P.; Blanchetiere, C.; Jacob, S.; Ledderhof, C.; Smelser, C.W.; Yadav, K.; Albert, J.
Reflectarray Design using Printed Electronics technology

Year: 2012

Abstract: A Ka-band reflectarray antenna with single sub-wavelength loop elements has been designed and fabricated using printed electronic technology. The reflectarray pattern is printed on a thin polyethylene terephthalate substrate using an inkjet printer with silver metal ink. The fabrication process and measurement results are reported.

Source title: Electronics Letters

Series Number: Volume 48 Issue 22

DOI: 10.1049/el.2012.3329

Link: Reflectarray Design using Printed Electronics technology

Chaharmir, M.R.; James, R.; Ethier, J.; Shaker, J.; Cuhaci, M.
Whistler mode resonance-cone transmissions at 100kHz in the OEDIPUS-C experiment

Year: 2012

Abstract: A radio transmitter was operated at one end of the tethered sounding rocket double payload OEDIPUS C, and a synchronized receiver at the other end. Both the transmitter and the receiver were connected to "double-V" dipoles. On the flight downleg after the tether had been cut, direct bistatic propagation experiments were carried out successfully with the transmitter-receiver pair. This Conference Paper/Presentation addresses the transmission of 300-s pulses at a carrier frequency of 100kHz between the dipoles over distances of about 1200m. The waves of interest propagate in the whistler mode close to its resonance cone, where the transmitter is situated in the cone apex. The radiated field under these conditions is computed as well as the resonance response of the receiving antenna, i.e., its effective length. In the whistler mode, the influence of the plasma is important and it results in qualitative changes in the structure of the radiated field and in the value of the receiving antenna effective length as compared to the free space case. Our main concern is the excitation and reception of a pulsed signal when time and space dispersion play important roles in both the delay and spreading of such a signal. © 2012. American Geophysical Union. All Rights Reserved.

Source title: Radio Science

Series Number: Volume 47 Issue 6

DOI: 10.1029/2012RS005054

Link: Whistler mode resonance-cone transmissions at 100kHz in the OEDIPUS-C experiment

Chugunov, Y.V.; Fiala, V.; Hayosh, M.; James, H.G.
Direction of arrival estimation for MIMO systems employing constellation-based precoding

Year: 2012

Abstract: A method is proposed to derive direction of arrival (DOA) information in a multiple-input single-output (MISO) or single-mode multiple-input multiple-output (MIMO) communications system that uses constellation-based limited feedback precoding. The DOA is estimated based on the distribution of precoders selected over multiple feedback intervals. The results show that coarse DOA estimates can be made with little additional system resource allocation. © 2012 IEEE.

Source title: IEEE Vehicular Technology Conference

DOI: 10.1109/VTCFall.2012.6399094

Link: Direction of arrival estimation for MIMO systems employing constellation-based precoding

Colman, G.W.K.; Wang, M.; Watson, S.
Regenerated femtosecond fibre Bragg gratings

Year: 2012

Abstract: We demonstrate the thermal regeneration of fibre Bragg gratings inscribed by direct writing using a femtosecond, infrared laser into standard SMF-28 and pure silica core fibres. Post-H 2 loading was used. The regeneration process is shown to extend the temperature operation of these gratings up to 1200°C. The temperature durability of regenerated 193nm-written gratings in SMF-28 fibre is presented for comparison. The ability to enhance the temperature durability of femtosecond inscribed index changes has significance beyond fibre Bragg gratings; for example, the micromachining of photonic components such as planar waveguides. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Source title: Proceedings of SPIE - The International Society for Optical Engineering

Series Number: Volume 8351

DOI: 10.1117/12.915937

Link: Regenerated femtosecond fibre Bragg gratings

Cook, K.; Smelser, C.; Canning, J.; Le Garff, G.; Lancry, M.; Mihailov, S.
On the error-rate performance of 4-state turbo codes with puncture-constrained DRP interleavers

Year: 2012

Abstract: It has often been demonstrated that conventional 4-state turbo codes do not perform well in either the waterfall or error-rate flare regions due to poor inherent convergence and distance properties, especially for highly-punctured codes. This Conference Paper/Presentation shows that the opposite can be true when carefully chosen data and parity puncture masks are used with matching puncture-constrained dithered relative prime (DRP) interleavers. With an interleaver length of K≥223 (8-meg), it is shown that waterfalls within 0.1 dB of capacity are possible for code rates R≥2/3. Waterfall performance can also be traded for improved distance to achieve very low error-rate flares. With an interleaver length of K=214 = 16384, R=8/9, and 50% data puncturing, a packet error rate of 10−6 was achieved within 0.57 dB of the corresponding binary sphere packing bound without using a cleanup code. © 2012 IEEE.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2012.6364028

Link: On the error-rate performance of 4-state turbo codes with puncture-constrained DRP interleavers

Crozier, S.; Gracie, K.
Chemical and pressure sensors using tapered optical fiber with polymer layer

Year: 2012

Abstract: The polymer polydimethylsiloxane (PDMS) whose refractive index and shape vary with absorbed organic compounds and pressure is used as the cladding layer in the tapered region of an optical fiber. The light propagation in the tapered region is influenced by the refractive index and shape changes of the PDMS layer due to the optical evanescent field. By monitoring the optical tapered fiber transmission power variations, an organic compound/pressure sensor is developed. © 2012 SPIE.

Source title: Proceedings of SPIE - The International Society for Optical Engineering

Series Number: Volume 8412

DOI: 10.1117/12.981982

Link: Chemical and pressure sensors using tapered optical fiber with polymer layer

Dai, X.; Ding, H.; Blanchetiere, C.; Mihailov, S.J.
Comparison of Propagation Characteristics at 700 and 2500 MHz Pertaining to Macrocellular and In-Building Coverage

Year: 2012

Abstract: This Conference Paper/Presentation presents results of a study comparing propagation characteristics in the 700 and 2500 MHz bands.

Source title: URSI-F Triennial Open Symp. On Radiowave Propagation and Remote Sensing, Ottawa, ON, April 30-May 3, 2013.

DOI: N/A

Link: Comparison of Propagation Characteristics at 700 and 2500 MHz Pertaining to Macrocellular and In-Building Coverage (PDF document)

de Jong, Y.L.C.; Rogers, D.V.
Modified turbo decoder for local content in single-frequency networks

Year: 2012

Abstract: DVB-SH systems rely on hierarchical modulation to insert local content in the complementary ground component. The local content is inserted as a low priority (LP) bit stream, while the global content will be transmitted as a high-priority (HP) bit stream. At the receiver, the standard approach of extracting the local content from the received signal requires to detect the global content first. Henceforth, one can remove the global content by subtracting the coded and modulated signal of the detected stream from the received signal. In this Conference Paper/Presentation, we propose and investigate a different approach of removing the global content from the received signal. In our new approach, a hybrid signal is designed, which contains (i) detected bits from the turbo decoder as systematic bits, and (ii) detected bits from the received signal prior to the turbo decoder as parity bits. This technique would relieve the receiver from performing coding and modulation on the detected global content so as to ensure less computational burden and a smaller latency than the current technology. The obvious tradeoff between complexity and performance would imply high bit error rates. Therefore, to mitigate the bit-error-rate performance degradation, we propose to modify the turbo decoder so that the systematic bit streams and the parity bit streams will be decoded differently with respect to their corresponding signal-to-noise ratios. Monte Carlo simulation results demonstrate that our proposed new scheme can achieve less computational complexity and latency in the slight sacrifice of error performance. © 2012 IEEE.

Source title: IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, BMSB

DOI: 10.1109/BMSB.2012.6264312

Link: Modified turbo decoder for local content in single-frequency networks

Debessu, Y.G.; Wu, H.-C.; Jiang, H.; Rong, B.
Electronically frequency-reconfigurable rectangular dielectric resonator antennas

Year: 2012

Abstract: The full implementation of a slot-fed frequency-reconfigurable rectangular dielectric resonator antenna (DRA) is described. It uses two conducting walls, on opposite vertical faces of the DRA, which are switched via conducting tabs to be in contact or not with the groundplane. Theoretical and experimental performance results for such DRAs, using either PIN or varactor diode switches, are described, where prototypes were designed to operate between 3-8 GHz. The PIN diode-loaded and varactor-loaded DRAs achieved a tuning range of 91% and 55%, respectively, with other performance metrics detailed in the communication. © 2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 60 Issue 6

DOI: 10.1109/TAP.2012.2194664

Link: Electronically frequency-reconfigurable rectangular dielectric resonator antennas

Desjardins, J.; McNamara, D.A.; Thirakoune, S.; Petosa, A.
Modal birefringence analysis of strained buried-core waveguides

Year: 2012

Abstract: A semianalytical study of modal birefringence in weakly strained and weakly guiding buried-core waveguides is presented. In this Conference Paper/Presentation, modal birefringence is expressed as a sum of form birefringence and stress birefringence. Stress birefringence is expressed as an overlap between the modal field and the stress birefringence distribution. This distribution is expressed analytically as two constant-value areas to which a spatially variant stress distribution emanating from the waveguide core is overlaid. The analysis can be expanded to include the effect of overetching and other variations that can be defined as mechanical inclusions in the cladding layer. Expressions for modal birefringence control as a function of material parameters are given, for the case of square, rectangular, and overetched waveguides. The conditions for width-independent birefringence control are identified. Modal birefringence values obtained from the analysis are compared to those obtained by finite-element analysis for the case of square, rectangular, and overetched waveguides. The modal birefringence values are shown to be within 5% of each other for a typical silica-on-silicon waveguide. © 2012 British Crown.

Source title: Journal of Lightwave Technology

Series Number: Volume 30 Issue 6

DOI: 10.1109/JLT.2012.2183854

Link: Modal birefringence analysis of strained buried-core waveguides

Dumais, P.
High-contrast germanium-doped silica-on-silicon waveguides

Year: 2012

Abstract: Silica-on-silicon planar lightwave circuits have a number of advantages including stability and low insertion loss to optical fiber networks. Standard GeO2 doping levels in the waveguide cores lead to a refractive index contrast, Δn/n, of 0.75%-2%. This range of index contrast requires relatively large bend radii in order to minimize bend losses. This limits the density scaling of these circuits. By using high dopant levels for a Δn/n of 4%, the bend radius can be decreased to less than 1 mm, from which significant gains in optical circuit density can be obtained. In addition, low-loss ring resonators with free spectral ranges of a few tens of gigahertz can be realized, enabling some additional optical signal processing and filtering on that scale. Optical devices with such high dopant levels have been reported by Bellman et al. in 2004 [1] but to the authors' knowledge, no other experimental work on high-delta GeO2-doped waveguides has been reported since. In this Conference Paper/Presentation, we present experimental measurements on high-delta devices including directional couplers, MMI couplers, Mach-Zehnder interferometers, and ring resonators. Device performance, including propagation loss, bend loss, interferometer contrast ratio and birefringence will be presented. We demonstrate that ring resonators with 40 GHz free spectral range can be fabricated for optical signal processing. © 2012 SPIE.

Source title: Proceedings of SPIE - The International Society for Optical Engineering

Series Number: Volume 8412

DOI: 10.1117/12.2000078

Link: High-contrast germanium-doped silica-on-silicon waveguides

Dumais, P.; Callender, C.; Blanchetiere, C.; Ledderhof, C.
The effect of dopant diffusion on modal birefringence in silica-on-silicon waveguides

Year: 2012

Abstract: Polarization-multiplexed optical signals require that the birefringence of optical devices be controlled. Birefringence in silica-on-silicon waveguides emerges from a combination of form birefringence and stress birefringence, both of which can be affected by the core dopant distribution in the case of rectangular-core waveguides. In this Conference Paper/Presentation, we present a numerical and experimental study of the effect of dopant diffusion on waveguide modal birefringence. In the numerical study, modal birefringence is calculated with a finite-element model that includes thermal stress effects. The effect of diffusion on form birefringence and stress birefringence will be illustrated. It will be shown that the initial index step of the waveguide has an influence on the evolution of the modal birefringence as a function of diffusion. In the experimental study, measurements of the phase and group birefringence will be presented as a function of waveguide width for waveguides with thermally diffused cores. It will be shown that thermal diffusion can be used for birefringence control of rectangular waveguides. © 2012 SPIE.

Source title: Proceedings of SPIE - The International Society for Optical Engineering

Series Number: Volume 8412

DOI: 10.1117/12.2000113

Link: The effect of dopant diffusion on modal birefringence in silica-on-silicon waveguides

Dumais, P.; Callender, C.; Ledderhof, C.
Development of novel low-cost reflectarrays

Year: 2012

Abstract: Design techniques have been developed to commercialize reflectarray designs. The use of low-cost, lossy materials in the design of traditional reflectarrays has been shown to substantially reduce their performance, precluding any competitiveness with solid reflectors. A novel design technique is presented that mitigates these losses and allows for performance on a par with commercial reflectors, while maintaining low costs. An atypical but highly successful radome material is also employed, with preliminary results showing ample environmental protection to allow the reflectarray to be used outdoors year-round, while still maintaining excellent electrical performance and low overall costs. © 1990-2011 IEEE.

Source title: IEEE Antennas and Propagation Magazine

Series Number: Volume 54 Issue 3

DOI: 10.1109/MAP.2012.6294005

Link: Development of novel low-cost reflectarrays

Ethier ,J.; Chaharmir, M.R.; Shaker, J.; Lee, D.
Reflectarray thinning using sub-wavelength coupled-resonant elements

Year: 2012

Abstract: A novel design technique is presented whereby a reflectarray comprising sub-wavelength coupled-resonant elements can be array thinned without significant reduction in gain at the centre frequency. A thinned reflectarray can more readily accommodate the integration of active components. © 2012 Canadian Crown.

Source title: Electronics Letters

Series Number: Volume 48 Issue 7

DOI: 10.1049/el.2012.0266

Link: Reflectarray thinning using sub-wavelength coupled-resonant elements

Ethier, J.; Chaharmir, M.R.; Shaker, J.
Loss reduction in reflectarray designs using sub-wavelength coupled-resonant elements

Year: 2012

Abstract: A novel design approach is proposed for designing high performance reflectarrays using low-cost, lossy substrates. Using sub-wavelength coupled-resonant elements, in particular sub-wavelength loops, one can dramatically reduce losses in reflectarrays and not incur significant gain drop due to the use of the lossy, low-cost substrate. It is further shown that the sub-wavelength loop achieves sufficient phase variation in a single layer design with a modest requirement in etching tolerance, making the loop superior to both the single and double-layer sub-wavelength patch elements. © 2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 60 Issue 11

DOI: 10.1109/TAP.2012.2207672

Link: Loss reduction in reflectarray designs using sub-wavelength coupled-resonant elements

Ethier, J.; Chaharmir, M.R.; Shaker, J.
New developments in reflectarray research at the Communications Research Centre Canada (CRC)

Year: 2012

Abstract: New developments in reflectarray research at the Communications Research Centre Canada will be presented. These developments focus on many areas such as: development of efficient methods for analysis and synthesis of reflectarrays, innovative cell elements, low cost, and wideband reflectarray. The Conference Paper/Presentation gives a brief overview of these topics and a more detailed presentation will be given at the conference. © 2012 IEEE.

Source title: 2012 15th International Symposium on Antenna Technology and Applied Electromagnetics, ANTEM 2012

DOI: 10.1109/ANTEM.2012.6262308

Link: New developments in reflectarray research at the Communications Research Centre Canada (CRC)

Ethier, J.; Chaharmir, M.R.; Shaker, J.
Predicting infinite periodic structure properties from finite structure models

Year: 2012

Abstract: Many techniques have been proposed for determining the properties of a finite-sized periodic structure from one consisting of the same elements and lattice, but infinite in size. In this Conference Paper/Presentation, we do the opposite, and describe an easily implemented moment method approach to determine the infinite structure properties from a related finite one, but importantly without the necessity of finding the current distribution on any element other than a single central one, and only having to find the solution of a matrix equation whose size is determined by the number of unknowns associated with the central element only. This is useful if one has access to a formulation (and source code) to analyze a single element and wish to know the properties of an infinite periodic structure comprised of such elements. Numerical validation is provided. © 2012 Wiley Periodicals, Inc.

Source title: Microwave and Optical Technology Letters

Series Number: Volume 54 Issue 10

DOI: 10.1002/mop.27094

Link: Predicting infinite periodic structure properties from finite structure models

Ethier, J.; McNamara, D.A.
Reflectarray design using similarity-shaped fragmented sub-wavelength elements

Year: 2012

Abstract: A new technique for synthesising reflectarray antennas is presented. It uses fragmented elements in a way that allows the elements of the reflectarray to be shape-optimised so that a high degree of geometric similarity exists between adjacent elements. This implies that in the reflectarray each element will see an electromagnetic environment that more closely emulates the infinite periodic environment used to compute the element's properties. It is shown experimentally that this results in aperture efficiencies closely approaching the upper bounds achievable with a given feed system, and is a significant improvement over that obtained with conventional reflectarrays. © 2012 The Institution of Engineering and Technology.

Source title: Electronics Letters

Series Number: Volume 48 Issue 15

DOI: 10.1049/el.2012.1457

Link: Reflectarray design using similarity-shaped fragmented sub-wavelength elements

Ethier, J.; McNamara, D.A.; Chaharmir, M.R.; Shaker, J.
Adaptive speech watermarking in wavelet domain based on logarithm

Year: 2012

Abstract: Considering the fact that the human auditory system requires more precision at low amplitudes, the use of a logarithmic quantization algorithm is an appropriate design strategy. Logarithmic quantization is used for the approximation coefficients of a wavelet transform to embed the secret bits. To improve robustness, the approximation coefficients are packed into frames and each secret bit is embedded into a frame. The experimental results show that the distortion caused by the embedding algorithm is adjustable and lower than that introduced by a standard ITU-T G.723.1 codec. Therefore, the marked signal has high quality (PESQ-MOS score around 4.0) and the watermarking scheme is transparent. The capacity is adjustable and ranges from very low bit-rates to 4000 bits per second. The scheme is shown to be robust against different attacks such as ITU-T G.711 (a-law and u-law companding), amplification and low-pass RC filters.

Source title: SECRYPT 2012 - Proceedings of the International Conference on Security and Cryptography

DOI: 10.5220/0004091704120415

Link: Adaptive speech watermarking in wavelet domain based on logarithm

Fallahpour, M.; Megias, D.; Najaf-Zadeh, H.
Kasami sequence studies for DTV transmitter identification

Year: 2012

Abstract: The transmitter identification of the DTV systems becomes crucial nowadays. Transmitter identification (TxID, or transmitter fingerprinting) technique is used to detect, diagnose and classify the operating status of any radio transmitter of interest. A pseudo random sequence was proposed to be embedded into the DTV signal before transmission. Thus, the transmitter identification can be realized by invoking the cross-correlation functions between the received signal and the possible candidates of the pseudo random sequences. Gold sequences and Kasami sequences are two excellent candidates for the transmitter ID sequences as they provide a large family of nearly-orthogonal codes. In order to investigate the sensitivity of the transmitter identification to different topologies and different Kasami sequence lengths, we present the analysis here for four different geometric layouts, namely circular distribution, doubly concentric and circular distribution, square array and hexagonal tessellation under the ENG (electronic news gathering) crews¿ working environment. The coverage area and the lowest received signal-to-interference ratio are considered as two essential parameters for the multiple-transmitter identification. It turns out to be that the larger the Kasami sequence length, the larger the received signal-to-interference ratio. Our new analysis can be used to determine the required Kasami sequence length for a specific broadcasting coverage © 2011 IEEE.

Source title: IEEE Transactions on Consumer Electronics

Series Number: Volume 58 Issue 4

DOI: 10.1109/TCE.2012.6414978

Link: Kasami sequence studies for DTV transmitter identification

Feng, X.; Wu, H.-C.; Wu, Y.; Wang, X.
Electrically thin free-standing phase and amplitude shifting surface for beam shaping applications

Year: 2012

Abstract: A free-standing phase and amplitude shifting surface (PASS) composed of four conductive layers separated by electrically thin dielectric sheets is presented in this Conference Paper/Presentation.This surface can be used for applications in which one must control both the phase and amplitude of electromagnetic waves propagating through it at every location over the aperture. The PASS provides a simple and efficient technique for manipulating the radiation pattern from a feed antenna for beam shaping applications. As a proof of concept, the technique is applied in the design of a flat-topped shaped beam antenna. © 2012 Wiley Periodicals, Inc.

Source title: Microwave and Optical Technology Letters

Series Number: Volume 54 Issue 7

DOI: 10.1002/mop.26911

Link: Electrically thin free-standing phase and amplitude shifting surface for beam shaping applications

Gagnon ,N.; Petosa, A.; McNamara, D.A.
Printed hybrid lens antenna

Year: 2012

Abstract: A novel printed hybrid lens antenna made of a 2-layer phase shifting surface (PSS) has been developed. It is a hybrid lens because the required operation is achieved by a combination of true phase correction (similar to a conventional lens, and previously reported PSS phase-correcting lenses) and amplitude-only correction (similar to a Fresnel zone plate). A prototype is fabricated and measured, revealing that the hybrid lens antenna has roughly twice the aperture efficiency of a Fresnel zone plate, and half that of a conventional lens. It provides an attractive compromise between performance, fabrication complexity and cost. © 2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 60 Issue 5

DOI: 10.1109/TAP.2012.2189711

Link: Printed hybrid lens antenna

Gagnon, N.; Petosa, A.; McNamara, D.A.
Real-time vandalism detection by monitoring object activities

Year: 2012

Abstract: This Conference Paper/Presentation proposes a novel method for the detection of vandalism events in video sequences. The method is based on a proposed definition for common vandal behaviors recorded on surveillance video sequences. To do this, the method monitors changes inside a restricted site containing vandalism-prone objects such as a vending machine, a pay phone, or a street sign. When an object is detected as leaving such a site, the proposed method checks if the site contains temporally consistent and significant static changes, representing damage. If there are such changes and given that the site is normally unchanged after legal use, a vandalism event is declared and the vandals are tracked. The proposed method is tested on video sequences showing real and simulated vandal behaviors and it achieves a detection rate of 96%. It detects different forms of vandalism such as graffiti and theft, and can handle sudden illumination changes, occlusions, and segmentation errors. The proposed method operates at a frame rate of 13 frames per second. © 2011 Springer Science+Business Media, LLC.

Source title: Multimedia Tools and Applications

Series Number: Volume 58 Issue 3

DOI: 10.1007/s11042-011-0751-z

Link: Real-time vandalism detection by monitoring object activities

Ghazal, M.; Vazquez, C.; Amer, A.
Improvements to the Message Content and Waveform of COSPAS-SARSAT Distress Beacons

Year: 2012

Abstract: Efforts are underway to design improved "second-generation" distress beacons for the Cospas-Sarsat system. Relative to existing (first-generation) beacons, these devices will transmit a greater variety of more precise information as well as improve geolocation and detection performance, helping to make SAR operations more effective. This paper describes a proposal for second-generation beacon design that maintains substantial interoperability with the existing system before MEOSAR becomes operational while simultaneously offering substantial performance improvements.

Source title: 30th AIAA International Communications Satellite System Conference (ICSSC)

DOI: 10.2514/6.2012-15207 

Link: Improvements to the Message Content and Waveform of COSPAS-SARSAT Distress Beacons

Gracie, K.; Hunt, A.; Andreadis, P.; King, J.
Superposed bragg grating made with femtosecond radiation for multiparameter sensing

Year: 2012

Abstract: We report the result of superposing IR ultrafast type II gratings made with different order phase masks in unloaded SMF-28 fiber. The process and the resulting spectra are described. © 2012 OSA.

Source title: Access Networks and In-house Communications, ANIC 2012

DOI: 10.1364/ANIC.2012.JTu5A.48

Link: Superposed bragg grating made with femtosecond radiation for multiparameter sensing

Grobnic, D.; Mihailov, S.J.; Walker, R.B.; Smelser, C.W.
Distributed sensing of spectrum occupancy and interference in outdoor 2.4 GHz Wi-Fi networks

Year: 2012

Abstract: A spectrum monitoring campaign was launched in an outdoor urban radio environment to investigate the potential deployment of Cognitive Radio (CR) Wi-Fi networks in the 2.4 GHz ISM band. The campaign used a CR learning platform with 4, 8, and 16 sensors. This Conference Paper/Presentation presents Wi-Fi spectrum occupancy and interference behaviour based on the outcome of one of the measurements using 16 GPS-synchronized sensors. At detection thresholds Td ≥-62dBm, long-term spectrum holes were dominant on all Wi-Fi channels. However, at Td < -62dBm channel availability decreased making CR operation more challenging. Wi-Fi traffic was dominated by management packets which correlated strongly with channel occupancy and far exceeded data and control packets. We noted management and data packet redundancies in the current IEEE 802.11 standard causing inefficient spectrum utilization. About 2/3rd of management packets were beacons, and more than 1/2 of data packets were data-reserved and null (no data). We also noted, at Td ≤-82dBm, a large number of Wi-Fi users more than can be attributed to the immediate surroundings of sensors, but a small set of them was dominant producing the bulk of spectrum occupancy and interference. In addition, at least 25% of these users were detected only once over the 5.5 hours measurement time span. The measurements showed spatial variations of the Wi-Fi environment over a small sensing area (21m-by-45m). We noted considerable non-homogeneity in the distribution of Wi-Fi interference at Td ≥-62dBm, but some non-homogeneity at Td ≤-82dBm. We also noted significant correlated fluctuations of received signal strength and non-reciprocal links over short distances between sensors. © 2012 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2012.6503318

Link: Distributed sensing of spectrum occupancy and interference in outdoor 2.4 GHz Wi-Fi networks

Hanna, S.A.; Sydor, J.
A compact 81-86 GHz branch line coupler using end-loaded transmission lines

Year: 2012

Abstract: This Conference Paper/Presentation presents a reduced-size 81-86 GHz branch line coupler using end-loaded transmission lines and implemented in a 0.15-μm GaAs HEMT technology. The fabricated coupler has a size-reduction of 50% in chip-area compared to a conventional branch line coupler. The measured results demonstrated a phase imbalance of 90 at 83 GHz with a phase error of less than +/−1 over the frequency band of interest. Over a frequency range of 81-86 GHz the measurements showed an amplitude imbalance of less than 1.1 dB, a return loss of less than 11 dB, and an isolation close to 15 dB. The obtained results confirm the potential of the proposed branch line coupler for low-cost, high performance, small size GaAs-based System-on-Chip radio transceivers for wireless and radio-over-fiber ultra high speed communication systems. © 2012 IEEE.

Source title: RWW 2012 - Proceedings: IEEE Radio and Wireless Symposium, RWS 2012

DOI: 10.1109/RWS.2012.6175290

Link: A compact 81-86 GHz branch line coupler using end-loaded transmission lines

Haroun, I.
Compact 60-GHz IPD-based branch-line coupler for system-on-package V-band radios

Year: 2012

Abstract: A compact 60-GHz band branch-line coupler using capacitively loaded lower-ground coplanar-waveguide (LG-CPW) lines has been successfully demonstrated in a glass-substrate integrated passive device technology. The fabricated coupler has a size reduction of more than 83% compared to that of a conventional CPW branch-line coupler. The capacitive loading is achieved by utilizing the signal layer and the LG of the LG-CPW structure to form microstrip open-circuited stubs. The measured results show a phase error of less than 0.5° between the coupler's output ports and an amplitude imbalance of less than 1.2 dB over the frequency band 57-64 GHz. The measurements also show that both the return loss and isolation are better than 25 dB at 60 GHz and better than 15 dB over the 57-64-GHz band. The proposed coupler is well suited for low-cost high-performance system-on-package V-band radio front ends for high data rate applications. © 2012 IEEE.

Source title: IEEE Transactions on Components, Packaging and Manufacturing Technology

Series Number: Volume 2 Issue 7

DOI: 10.1109/TCPMT.2012.2186450

Link: Compact 60-GHz IPD-based branch-line coupler for system-on-package V-band radios

Haroun, I.; Plett, C.; Hsu, Y.-C.; Chang, D.-C.
A new type of GaN HEMT based high power high-pass/low-pass phase shifter at X band

Year: 2012

Abstract: This Conference Paper/Presentation presents a new type of robust GaN HEMT-based high power phase shifter operating at X-band. The proposed 0°/45° high-pass/low-pass phase shifter exhibits low insertion loss (2.5 dB), good return loss, and amplitude variation lower than 0.5 dB for the two phase states over the entire operational bandwidth ranging from 6 to 13 GHz. The relative phase performance is fairly constant over the bandwidth. The proposed phase shifter MMIC has been successfully demonstrated using a 0.8 µm gate GaN HEMT process. © 2012 IEEE.

Source title: IEEE MTT-S International Microwave Symposium Digest

DOI: 10.1109/MWSYM.2012.6259738

Link: A new type of GaN HEMT based high power high-pass/low-pass phase shifter at X band

Hettak, K.; Ross, T.; Gratton, D.; Wight, J.
High-power broadband GaN HEMT SPST/SPDT switches based on resonance inductors and shunt-stacked transistors

Year: 2012

Abstract: Novel X-band high-power monolithic SPST/SPDT switches in coplanar GaN technology are presented. The SPDT switch exhibits 1:6dB on-state insertion loss and better than 20dB isolation. Power handling measurements have shown that the 1dB compression point occurs with an input power equal to 38dBm at 10GHz. A combination of techniques were used to yield higher power handling while preserving low loss and high isolation. These circuit techniques include the use of stacked HEMTs to improve power handling and to minimize the loss and maintain high isolation, and also the use of a resonance inductor in parallel with the series HEMTs to improve the isolation of the switch. Simulated and experimental results are presented in support of the novel switches. © 2012 European Microwave Assoc.

Source title: European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 7th European Microwave Integrated Circuits Conference, EuMIC 2012

DOI: N/A

Link: High-power broadband GaN HEMT SPST/SPDT switches based on resonance inductors and shunt-stacked transistors

Hettak, K.; Ross, T.; Irfan, N.; Gratton, D.; Yagoub, M.C.E.; Wight, J.
Highly integrated 60GHz SSB MMIC mixer with no DC power consumption based on subharmonic LO and CPW circuits in GaAs pHEMT technology

Year: 2012

Abstract: This Conference Paper/Presentation presents the results of a novel miniature single sideband (SSB) subharmonic direct upconverter GaAs MMIC with no DC power consumption and developed in uniplanar technology. The mixer uses 100MHz I and Q signals to directly modulate the second harmonic of a 30GHz carrier, producing the required 60.1GHz RF output. Two pair of antiparallel diodes reduce feed-through of the fundamental 30GHz signal to the RF output while novel coplanar waveguide centre conductor-based structures provide matching. This 2.1mm2 chip also uses a reduced-size Wilkinson divider based on asymmetric coplanar stripline and a standard size CPW 90° coupler. It exhibits a conversion loss of less than 11dB and a high image rejection ratio of greater than 20dB over a wide frequency range from 52GHz to 61GHz. © 2012 European Microwave Assoc.

Source title: European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 7th European Microwave Integrated Circuits Conference, EuMIC 2012

DOI: N/A

Link: Highly integrated 60GHz SSB MMIC mixer with no DC power consumption based on subharmonic LO and CPW circuits in GaAs pHEMT technology

Hettak, K.; Ross, T.; Irfan, N.; Morin, G.; Yagoub, M.C.E.; Wight, J.
A hardware architecture for motion compensated video frame rate up-conversion

Year: 2012

Abstract: A hardware architecture for motion compensated, video frame rate up-conversion (MC-FRUC) applications is presented in this Conference Paper/Presentation. The MC-FRUC architecture has been designed based on an advanced motion estimation (ME) and motion compensated frame interpolation (MCFI) algorithm to achieve interpolated frames with high level of quality. The proposed architecture is a flexible and highly parallel MC-FRUC that has been designed to support frame rate-up conversion (FRUC) for high definition (HD) video at high frame rate. The ME building block of the MC-FRUC circuit is a reconfigurable structure designed to support reconfigurations for single or multiple reference frames. The MCFI building block performs frame interpolation with the objective of minimizing of block artifacts, overlapping, and holes for the interpolated frames. Hardware implementations for the MC-FRUC design were carried out on FPGA where the circuit high performance FRUC capability has been validated.

Source title: WSEAS Transactions on Circuits and Systems

Series Number: Volume 11 Issue 2

DOI: N/A

Link: A hardware architecture for motion compensated video frame rate up-conversion NOTE: A login may be required to access this site.

Ho, H.
Pluralistic licensing

Year: 2012

Abstract: We introduce the concept of 'pluralistic licensing', which we describe as the award of licenses under the assumption that opportunistic secondary spectrum access will be allowed, and that interference may be caused to the primary with parameters and rules that are known to the primary at the point of obtaining the license. A key aspect of the concept is that the primary will choose from a range of offered 'pluralistic licenses' each with associated fees, and each specifying alternative opportunistic access rules and associated interference characteristics. Our proposal is a novel means to take forward spectrum licensing which is fair to both primary and secondary users and takes into account the requirements of both parties. The objective is to incentivize the primary to obtain this type of license through means such as a reduced license fee, whereby the opportunistic secondary spectrum access will use 'cognitive radio' mechanisms to avoid causing interference to the primary or to otherwise keep interference within known parameters […]. © 2012 IEEE.

Source title: 2012 IEEE International Symposium on Dynamic Spectrum Access Networks, DYSPAN 2012

DOI: 10.1109/DYSPAN.2012.6478113

Link: Pluralistic licensing

Holland, O.; De Nardis, L.; Nolan, K.; Medeisis, A.; Anker, P.; Minervini, L.F.; Velez, F.; Matinmikko, M.; Sydor, J.
Improved ICI estimation for mobile OFDM systems

Year: 2012

Abstract: To combat Inter-Carrier Interference (ICI) in mobile OFDM systems, ICI can be reconstructed and removed from the received signal with the aid of channel estimation and decision-feedback. Successful ICI cancellation hinges on accurate channel estimation, which includes both the channel gains and ICI gains, the multiplicative coefficients to the neighbor subcarrier signals representing their power leakage. The channel estimation methods based on the statistical property of the ICI gains were previously proposed by the authors. In this Conference Paper/Presentation, we propose improved ICI gain estimation scheme exploiting the sparse property of the multipath fading channels. The scaling relationship between ICI gain vectors is also further exploited to significantly improve the performance of ICI gain estimation. © 2012 IEEE.

Source title: IEEE Wireless Communications and Networking Conference, WCNC

DOI: 10.1109/WCNC.2012.6213931

Link: Improved ICI estimation for mobile OFDM systems

Hong, Z.; Zhang, L.; Thibault, L.
A type-based equalization technique for frequency response distortion compensation

Year: 2012

Abstract: In this paper, we present a patent pending type-based equalizer estimation technique to compensate for in-band amplitude and group delay distortions in analog/RF circuits. Its underlining principle is that for a given modulation scheme and pulse-shaping function, the modulated signal has a unique statistical distribution, and that any in-band amplitude and group delay variations in the circuit distort its output statistical distribution. The difference between the ideal and the output statistics contains the distortion information, and is used to design an equalizer. Computer simulations have shown that the type-based technique can accurately determine the equalizer that effectively compensates for the analog/RF circuit in-band distortions, thereby significantly improving the system performance.

Source title: Proceedings: IEEE Radio and Wireless Symposium

DOI: 10.1109/RWS.2012.6175291

Link: A type-based equalization technique for frequency response distortion compensation

Huang, X.; Caron, M.
Statistics-based LINC amplifier calibration

Year: 2012

Abstract: In this Conference Paper/Presentation, we describe the LINC amplifier concept, and discuss gain and phase mismatch issues that reduce its linearity and degrade its performance. A self-calibration approach for the LINC amplifier is proposed, which is based on minimizing a distortion measure of its output signal in the statistical domain. Computer simulations are carried out to validate the proposed LINC amplifier calibration approach. It is demonstrated that the gain and phase mismatches in the LINC amplifier introduce severe nonlinear distortions to its output signal, which severely degrades the overall system performance, and that the proposed calibration approach accurately determines the gain and phase mismatches, effectively compensates for their effects, and significantly improves the LINC amplifier performance. © 2012 IEEE.

Source title: ISCAS 2012 - 2012 IEEE International Symposium on Circuits and Systems

DOI: 10.1109/ISCAS.2012.6271462

Link: Statistics-based LINC amplifier calibration

Huang, X.; Caron, M.
Estimation of Time Varying QoE for High Definition IPTV Distribution

Year: 2012

Abstract: High Definition (HD) content delivery over IP networks is now a reality in the entertainment marketplace. Such networks can suffer packet loss, especially on the last mile link. This results in time-variant video quality. In this paper we first present an analysis of the human perception of network impairment on HD IPTV quality. Second, we propose a method, based on common objective measurements, to estimate subjective judgments of time-variant quality. A testbed was deployed to emulate a real use case of delivering high definition TV material over an IPTV network. The quality of the delivered H.264/AVC encoded video was evaluated objectively in an emulated environment where packet loss impairments were generated. Objective measurements were then compared to continuous subjective quality ratings. Based on the obtained results, highly correlated models were developed for the estimation of instantaneous user judgment of impaired HD broadcast IPTV.

Source title: IEEE Consumer Communications and Networking

DOI: 10.1109/CCNC.2012.6181111

Link: Estimation of Time Varying QoE for High Definition IPTV Distribution

Issa, O.; Spreranza, F.; Li, W.; Liu, H.
Long-period gratings based on surface plasmon polariton waveguides in fluorinated polymer

Year: 2012

Abstract: This letter presents devices composed of long-period gratings and long-range surface plasmon polariton waveguides. The waveguide is formed by embedding a thin Au stripe in a low optical absorption perfluorocyclobutane polymer. The grating structure is created on a corrugated silica substrate and then transferred to the polymer layer, producing a periodic modulation of refractive index along the waveguide. Strong grating resonances are observed. The coupling mechanism and the device thermal dependence are examined. © 1989-2012 IEEE.

Source title: IEEE Photonics Technology Letters

Series Number: Volume 24 Issue 23

DOI: 10.1109/LPT.2012.2224329

Link: Long-period gratings based on surface plasmon polariton waveguides in fluorinated polymer

Jiang, J.; Callender, C.L.; Jacob, S.
Long period gratings based on silica PLCs for optical signal processing applications

Year: 2012

Abstract: Planar waveguide long period gratings have been implemented by creating a permanent refractive index modulation on the lower cladding of a waveguide. Design and fabrication of silica and polymer LPG devices for applications in high-speed optical signal processing are presented.

Source title: Integrated Photonics Research, Silicon and Nanophotonics, IPRSN 2012

DOI: 10.1364/IPRSN.2012.ITu4B.3

Link: Long period gratings based on silica PLCs for optical signal processing applications

Jiang, J.; Dumais, P.; Ledderhof, C.J.; Callender, C.L.
Bending devices based on long-range surface plasmon polariton waveguides embedded in fluorinated polymer

Year: 2012

Abstract: This work presents low-loss bending waveguides based on long-range surface plasmon polaritons (LRSPP) excited by end-fire coupling. The waveguides were fabricated by embedding thin film stripes of gold in a low optical absorption perfluorocyclobutane (PFCB) polymer. © 2012 OSA.

Source title: Optical Society of America, 2012

DOI: 10.1364/ANIC.2012.JTu5A.10

Link: Bending devices based on long-range surface plasmon polariton waveguides embedded in fluorinated polymer NOTE: A login may be required to access this site.

Jiang, J.; Jacob, S.; Callender, C.L.
Trust transitivity and conditional belief reasoning

Year: 2012

Abstract: Trust transitivity is a common phenomenon embedded in human reasoning about trust. Given a specific context or purpose, trust transitivity is often manifested through the humans' intuition to rely on the recommendations of a trustworthy advisor about another entity that the advisor recommends. Although this simple principle has been formalised in various ways for many trust and reputation systems, there is no real or physical basis for trust transitivity to be directly translated into a mathematical model. In that sense, all mathematical operators for trust transitivity proposed in the literature must be considered ad hoc; they represent attempts to model a very complex human phenomenon as if it were lendable to analysis by the laws of physics. Considering this nature of human trust transitivity in reality, any simple mathematical model will essentially have rather poor predictive power. In this Conference Paper/Presentation, we propose a new interpretation of trust transitivity that is radically different from those described in the literature so far. More specifically, we consider recommendations from an advisor as evidence that the relying party will use as input arguments in conditional reasoning models for assessing hypotheses about the trust target. The proposed model of conditional trust transitivity is based on the framework of subjective logic. © 2012 IFIP International Federation for Information Processing.

Source title: IFIP Advances in Information and Communication Technology

Series Number: Volume 374 AICT

DOI: 10.1007/978-3-642-29852-3_5

Link: Trust transitivity and conditional belief reasoning

Josang, A.; Azderska, T.; Marsh, S.
Opportunistic routing in tactical networks

Year: 2012

Abstract: Providing network functionality for military VHF tactical networks has been problematic for many years. Existing schemes have struggled to provide multi-hop transmission of combined voice and data traffic in this dynamic and very low bandwidth environment. Research has shown that the overhead introduced by existing MANET routing techniques can swamp tactical networks of non-trivial size and topological complexity. In this Conference Paper/Presentation we propose the use of a cross-layered approach combined with opportunistic routing to provide enhanced opportunistic routing (EOR) in mobile tactical networks. This technique makes per-packet forwarding decisions based only on preset domain knowledge, information from lower layers, and information from each individual packet. Because this technique does not build or maintain any network topology state it can operate with no network layer overhead. EOR has been simulated in Qualnet and compared to both AODV and OLSRv2 in large and small tactical networks. EOR was found to be superior to both AODV and OLSRv2 in terms of packet delivery, delay, and network overhead. © 2012 IEEE.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2012.6364126

Link: Opportunistic routing in tactical networks

Kidston, D.; Shi, M.
A multicast routing technique for tactical networks

Year: 2012

Abstract: Providing integrated network functionality in VHF tactical networks has been problematic for many years. Modern MANET routing techniques can swamp the limited bandwidth of ground-based tactical networks while legacy techniques are inefficient. In this Conference Paper/Presentation, we expand on our previous work using a cross-layered approach and propose a new technique for Multicast Enhanced Opportunistic Routing (MEOR). MEOR makes per-packet forwarding decisions based only on pre-set domain knowledge, information from lower layers, and information encoded in individual packets. Because this technique does not build or maintain any topology state, it has no network layer overhead. MEOR has been simulated in Qualnet and compared to Simplified Multicast Forwarding (SMF), classic flooding, and local broadcast in large and small tactical scenarios. MEOR was found superior in terms of packet delivery rates and overhead. © 2012 IEEE.

Source title: Proceedings - IEEE Military Communications Conference MILCOM

DOI: 10.1109/MILCOM.2012.6415705

Link: A multicast routing technique for tactical networks

Kidston, D.; Shi, M.
Low-complexity automated depth-order estimation for 2D-to-3D video conversion

Year: 2012

Abstract: The increasing popularity of 3D TV creates the desire for more 3D video content. Unfortunately, it will take much time for there to be an abundance of 3D video content derived from stereoscopic cameras. However, there currently exists a vast quantity of 2D video material that can potentially be converted to 3D. Converting 2D into 3D is a complex process, and so can be costly. Thus, an automated solution that can be achieved with low-complexity would be desirable. Our past research work has already resulted in a real-time 2D-to-3D conversion technique, but this generates a surrogate depth map that results in pseudo-3D and not necessarily accurate 3D. Our current research focuses on improving the accuracy of the 3D effect by implementing a technique composed of a multi-step process to determine the depth-order of objects, with respect to the camera, in each frame of a video sequence, and incorporating into our existing technique. The multi-step process can be summarized as follows: detect pixels that belong to an edge; use block-based motion estimation to determine if an edge pixel is moving and thus belongs to a moving edge (i.e., occlusion boundary); determine which of either the left or right side block moves with the moving edge pixel, and by deduction determines the occluding object; select seed points from the moving edge pixels; implement color-only region growing from each seed; cluster regions into objects based on their proximity; globally assign depth-order to the objects based on perceived viewing perspective of a frame; and modify the original surrogate depth map to create a more accurate depth map. Test results show that this is a very effective and fast technique for deriving the depth-order of objects and generating more accurate depth map values. © 2012 SPIE-IS&T.

Source title: Proceedings of SPIE - The International Society for Optical Engineering

Series Number: Volume 8305

DOI: 10.1117/12.906231

Link: Low-complexity automated depth-order estimation for 2D-to-3D video conversion

Klepko, R.
Broadcasting in multihop wireless networks: The case for multi-source network coding

Year: 2012

Abstract: Network Coding, in particular Random Linear Network Coding, has been extensively researched for communication in multihop wireless networks, such as MANETs. A key aspect of random linear network coding is the definition of generations, the set of native data packets that can be coded together. To keep the decoding complexity and packet latency low, generations are typically small. In addition, to simplify generation management, it is usually assumed that a generation only contains packets originating from the same source. For broadcast scenarios, we show via examples, analytically derived lower bounds, and protocol simulations that the latter restriction reduces the coding gains that are achievable. Allowing packets from different sources to be combined (i.e., coded together) can improve PDR, reduce packet latency, and further reduce the number of packet transmissions at the MAC layer. We also discuss the added complexity that results from having packets from different sources in a single generation and propose our solution, embedded in a RLNC broadcast protocol called ARLNCCF. © 2012 IEEE.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2012.6363697

Link: Broadcasting in multihop wireless networks: The case for multi-source network coding

Kunz, T.; Mahmood, K.; Li, L.
Quality-of-experience perception for video streaming services: Preliminary subjective and objective results

Year: 2012

Abstract: Quality-of-Experience (QoE) is a human centric notion that produces the blue print of human perception, feelings, needs and intentions while Quality-of-Service (QoS) is a technology centric metric used to assess the performance of a multimedia application and/or network. To ensure superior video QoE, it is important to understand the relationship between QoE and QoS. To achieve this goal, we conducted a pilot subjective user study simulating a video streaming service over a broadband network with varying distortion scenarios, namely packet losses (0, 0.5, 1, 3,7, and 15%), packet reorder (0, 1, 5, 10, 20, and 30%), and coding bit rates (100, 400, 600, and 800 Kbps). Users were asked to rate their experience using a subjective quantitative metric (termed Perceived Video Quality, PVQ) and qualitative indicators of "experience. " Simulation results suggest a) an exponential relationship between PVQ and packet loss and between PVQ and packet reorder, and b) a logarithmic relationship between PVQ and video bit rate. Similar trends were observed with the qualitative indicators. Exploratory analysis with two objective video quality metrics suggests that trends similar to those obtained with the subjective ratings were obtained, particularly with a full-reference metric. © 2012 APSIPA.

Source title: 2012 Conference Handbook - Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, APSIPA ASC 2012

DOI: N/A

Link: Quality-of-experience perception for video streaming services: Preliminary subjective and objective results

Laghari, K.U.R.; Issa, O.; Speranza, F.; Falk, T.H.
A token-based connectivity update scheme for unmanned aerial vehicle ad hoc networks

Year: 2012

Abstract: Code division multiple access mobile ad hoc networks (CDMA-MANETs) are envisioned to be the next-generation networking architecture for networking military platforms in a battlefield. In this Conference Paper/Presentation we consider a CDMA ad hoc network consisting of multiple unmanned aerial vehicles (UAVs). We propose a token-based connectivity update scheme to solve the code collision problem in assigning code channels as well as the network link update problem for the CDMA UAV ad hoc network. Our proposed scheme uses a token message, which continuously circulates around the network in a non-predetermined order, to conduct assignment of code channels for each UAV. By using the broadcast properties of the wireless communication media, our proposed scheme is able to discover new or lost neighbors almost in real time. Moreover, the proposed token-based connectivity update scheme implements spatial reuse of code channels, which is mandatory in large-scale ad hoc networks due to the limited size of the CDMA code set. We then derive a theoretical result for approximating the connectivity update latency, which is further verified through computer simulations. © 2012 IEEE.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2012.6363645

Link: A token-based connectivity update scheme for unmanned aerial vehicle ad hoc networks

Li, J.; Wei, Z.; Zhou, Y.; Deziel, M.; Lamont, L.; Yu, F.R.
Packet delay statistics of the multichannel selective-repeat automatic-repeat-request

Year: 2012

Abstract: In this Conference Paper/Presentation, we conduct stochastic modeling and analysis of the packet end-to-end delay in a multichannel selective-repeat automatic-repeat-request (MSR-ARQ) protocol. In this protocol, the transmitter continuously transmits packets over multiple parallel channels and retransmits erroneously received packets with either dynamic or static packet-to-channel scheduling policy. Under the assumption that packets are always supplied at the transmitter, denoted by the saturated traffic condition, we analyze the steady state probability distribution function of the delay of an arbitrary packet, which is measured by the duration between the instant at which the packet is transmitted for the first time and the time it departs from the resequencing queue at the receiver. Using the analysis result, we numerically compute the distribution function for chosen values of the number of channels and the error rates to demonstrate the computational effectiveness of the result. With numerical and simulation results, we then study the performance of MSR-ARQ in terms of the mean packet delay and compare the two scheduling policies. It is shown that the dynamic scheduling achieves a better packet delay performance than the static scheduling.With the dynamic scheduling and the presence of difference between the error rates of parallel channels, the mean packet delay decreases as the difference between channels' error rates increases.Moreover, the number of parallel channels has an insignificant impact on the mean packet delay, which shows that the use of parallel channels is favorable for the wireless or mobile communications to increase the data transmission rate while keeping the mean packet delay at an acceptable level. © Her Majesty the Queen in Right of Canada 2011.

Source title: Wireless Personal Communications

Series Number: Volume 66 Issue 2

DOI: 10.1007/s11277-011-0325-4

Link: Packet delay statistics of the multichannel selective-repeat automatic-repeat-request

Li, J.; Zhao, Y.Q.; Zhou, Y.; Lamont, L.
Cooperative MAC scheduling in CDMA-MANETs with multiuser detection

Year: 2012

Abstract: Code division multiple access mobile ad hoc networks (CDMA-MANETs) will be a next-generation wireless networking architecture to connect various military platforms. The classic contention-based MAC protocols are inappropriate for tactical ad hoc networks, where more rigid requirements for the quality of service (QoS) (e.g., guaranteed packet delivery) have to be satisfied. In this Conference Paper/Presentation, we propose a contention-free medium access control (MAC) scheduling framework for CDMA-MANETs where each mobile unit is capable of multiuser detection (MUD) as well. In this MAC scheduling scheme, how and when a pending data packet is going to be transmitted are cooperatively determined by the respective transmitter-receiver pair. Furthermore, to fully utilize the functionality provided by multiuser detection, our proposed cooperative MAC scheduling scheme is able to schedule multiple transmitters to simultaneously transmit packets to a same receiver. Computer simulations are carried out to demonstrate the performance of the proposed cooperative MAC scheduling framework. It is confirmed from simulation results that the packet average delay increases with either the packet generation rate or the network size. More importantly, the proposed cooperative MAC scheduling framework is more suitable for MUD-enabled CDMA-MANETs with heavier network traffic and possibly a larger number of network nodes. © 2012 ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

Source title: Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering

Series Number: Volume 89 LNICST

DOI: 10.1007/978-3-642-29096-1_10

Link: Cooperative MAC scheduling in CDMA-MANETs with multiuser detection

Li, J.; Zhou, Y.; Deziel, M.; Lamont, L.
Swarm mobility and its impact on performance of routing protocols in MANETs

Year: 2012

Abstract: In a mobile ad hoc network (MANET), node mobility has significant impact on the performance of routing protocols. In this Conference Paper/Presentation we investigate the impact of the swarming behavior of mobile nodes on the performance of MANET routing protocols, analytically and through simulation. We propose a Markov swarm mobility model to characterize time-dependent changes in the network topology, based on which a quantized collaboration degree is obtained. The proposed Markov swarm mobility model is validated through statistical hypothesis testing of simulation data. Then the performance of MANET routing protocols is studied in terms of hop count, routing overhead, and average end-to-end delay of a data packet. We derive an exact probability distribution function of the hop count, and analytic expressions for approximating the routing overhead and the average end-to-end delay. Numerical and simulation results are used to demonstrate the validity of the theoretical derivations. Trends of these performance metrics are discussed based on numerical results. An important observation is that, when a swarm of mobile nodes moves in a more collaborative manner, both the routing overhead and the average end-to-end delay of data packets are significantly reduced. The analysis developed in this Conference Paper/Presentation can help gain insight into the effect of group mobility on the performance of MANET proactive routing, and provide guidelines for designing appropriate routing techniques for MANETs with swarm mobility patterns. © 2012 Elsevier B.V. All rights reserved.

Source title: Computer Communications

Series Number: Volume 35 Issue 6

DOI: 10.1016/j.comcom.2011.12.007

Link: Swarm mobility and its impact on performance of routing protocols in MANETs NOTE: A login may be required to access this site.

Li, J.; Zhou, Y.; Lamont, L.; Richard, Yu F.; Rabbath, C.-A.
Performance analysis of multichannel radio link control in MIMO systems

Year: 2012

Abstract: With rapid advances in wireless communications, multiple-input multiple-output (MIMO) antennas technology has been integrated into next-generation wireless communication standards. In this Conference Paper/Presentation, we introduce a MIMO system model, propose a multichannel radio link control protocol and a dynamic channel scheduling policy. We then conduct a performance study on the multichannel link control protocol with two different scheduling policies (i.e., dynamic and static scheduling) using simulations. Simulation results show that the dynamic scheduling outperforms the static scheduling. It is observed that the average packet delay with the dynamic scheduling increases with the average error rate of parallel channels, but decreases with the variance in the error rates of parallel channels. More interestingly, the number of parallel channels has only an insignificant impact on the average packet delay, when the dynamic scheduling is applied in MIMO systems, from which we confirm that the use of parallel channels is a favorable option for packet data networking in the point of view of the link-layer performance. © 2012 ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

Source title: Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering

Series Number: Volume 89 LNICST

DOI: 10.1007/978-3-642-29096-1_8

Link: Performance analysis of multichannel radio link control in MIMO systems

Li, J.; Zhou, Y.; Liu, Y.; Lamont, L.
Minimum Connected Dominating Set in realistic tactical radio network conditions

Year: 2012

Abstract: The issue of packet delivery loss is considered in formulating the problem of Minimum Connected Dominating Set(s) (MCDS) for tactical radio networks. A complete solution is devised to identify all the MCDS in the network. A heuristic algorithm is also developed that shows promising properties. The model is applied to study a typical tactical deployment scenario and to obtain useful benchmarks for MCDS in realistic tactical environment. The results illustrate that without considering realistic link conditions, the existing protocol Simplified Multicast Forwarding (SMF) forms smaller Connected Dominating Set(s) (CDSs) than required, which leads to low packet delivery ratios. © 2012 IEEE.

Source title: Proceedings - IEEE Military Communications Conference MILCOM

DOI: 10.1109/MILCOM.2012.6415782

Link: Minimum Connected Dominating Set in realistic tactical radio network conditions

Li, L.; Rutagemwa, H.; Kunz, T.
Robust networking for bandwidth constrained mobile tactical radios

Year: 2012

Abstract: This work investigates an efficient and robust broadcast / multicast scheme for the bandwidth limited tactical environment. A local neighborhood based broadcast / multicast protocol is enhanced through managing dynamic link conditions to achieve required delivery ratio. Employing a realistic tactical radio model and practical tactical deployment scenarios, the proposed mechanism is evaluated using a network simulator. Compared with one of the most efficient standard protocols, the simplified multicast forwarding, the proposed scheme demonstrates improved efficiency and robustness. © 2012 IEEE.

Source title: IEEE Vehicular Technology Conference

DOI: 10.1109/VETECS.2012.6240025

Link: Robust networking for bandwidth constrained mobile tactical radios

Li, L.; Shi, M.; Kunz, T.
On designing bandwidth constrained mobile tactical networks for complex terrains

Year: 2012

Abstract: This Conference Paper/Presentation describes a design approach adopted in developing networking capabilities for NATO's next generation narrowband waveform tactical radios. Providing improved link spectral efficiencies and maintaining long communication range, these new radios enable an opportunity to utilize mult-hop networking features that have been developed for mobile ad hoc networks during the past decade. The challenge, however, is to select and devise networking solutions of predictable and robust performance. For this purpose, a network-science-based approach is taken to first capture and understand the fundamental network properties exhibited when connecting tactical radios. This application of an empirical foundation has proven effective in discovering the dynamic network topological behavior and connectivity attributes. The results illustrate critical implications on the network protocol design and provide important guidance on selecting required networking solutions. © 2012 IEEE.

Source title: IEEE Communications Magazine

Series Number: Volume 50 Issue 2

DOI: 10.1109/MCOM.2012.6146498

Link: On designing bandwidth constrained mobile tactical networks for complex terrains

Li, L.; Vigneron, P.; Brown, C.; Shi, M.; Kunz, T.
Joint Replay Detection in Tactical Networks

Year: 2012

Abstract: In this paper, replay attacks and their associated risks in mobile tactical networks are analyzed and a cooperative joint detection scheme is evaluated. The scheme adopts a combination of duplicated frame detection and link likelihood verification to defend against both local and remote replays. A formal analytical framework is established employing realistic tactical radio models and network scenarios. The results obtained illustrate the network-wide risk of the attack and the effectiveness of the detection scheme.

Source title: The IEEE International Conference on Communications (ICC) 2012.

DOI: 10.1109/ICC.2012.6364514

Link: Joint Replay Detection in Tactical Networks

Li, L.; Vigneron, P.; Mason, P.; Kunz, T.
Design of mM-W fully integrated CMOS standing-wave VCOs using low-loss CPW resonators

Year: 2012

Abstract: The design of two fully integrated 43-GHz voltage-controlled oscillators (VCOs) implemented in a 90-nm CMOS process is presented. Both use standing-wave transmission line resonators instead of a lumped tank to provide extended output frequency ranges and relatively low phase noise (PN). Coplanar waveguide structures with and without slow-wave features were employed in the two VCO circuits. The test results of the manufactured chips were compared. The circuit with the slow-wave feature showed a lower PN (-102.7 dBc/Hz at 1 MHz), whereas the one without the slow-wave structure showed a wider tuning range (1.96 GHz). The two VCOs were developed for use in licensed E-band transceiver systems. © 2011 IEEE.

Source title: IEEE Transactions on Circuits and Systems II: Express Briefs

Series Number: Volume 59 Issue 2

DOI: 10.1109/TCSII.2011.2180095

Link: Design of mM-W fully integrated CMOS standing-wave VCOs using low-loss CPW resonators

Li, M.; Amaya, R.E.
H.264 error resilience adaptation to IPTV applications

Year: 2012

Abstract: TV delivery over IP networks (i.e. IPTV) has emerged as one of the major distribution and access techniques for broadband multimedia services. IPTV adopts H.264 as its coding standard due to its high video compression efficiency as well as powerful error resilience features. This Conference Paper/Presentation presents studies on some of the H.264/AVC error resilience features applied to IPTV applications, namely, high definition (i.e., HD IPTV) and wireless/handheld extension. Test systems are deployed to simulate: (1) The delivery of lower resolution TV programs over wireless channels; (2) The delivery of HD video over an xDSL based IPTV network. Flexible Macroblock Ordering (FMO) slice grouping is assessed in handheld IPTV applications. Optimal slice size is obtained for HD video transmission over impaired channels. The quality of experience related to the Instantaneous Decoding Refreshing (IDR) interval is characterized for HD IPTV. © 2012 IEEE.

Source title: IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, BMSB

DOI: 10.1109/BMSB.2012.6264285

Link: H.264 error resilience adaptation to IPTV applications

Li, W.; Liu, H.; Issa, O.; Zhang, L.
Compact reconfigurable UWB antenna integrated with SIRs and switches for multimode wireless communications

Year: 2012

Abstract: A kind of reconfigurable wide slot UWB antenna integrated with stepped impedance resonators (SIRs) and ideal switches is presented. The proposed antenna 1 has dual notch band functions which are obtained by using two stepped impedance stub loaded SIRs. The three reconfigurable models are investigated and discussed. The measurement results with ideals switches demonstrate the performances of proposed reconfigurable antennas. The designed reconfigurable antennas can be suitable for future multi-mode wireless communications systems. © IEICE 2012.

Source title: IEICE Electronics Express

Series Number: Volume 9 Issue 7

DOI: 10.1587/elex.9.629

Link: Compact reconfigurable UWB antenna integrated with SIRs and switches for multimode wireless communications

Li, Y.; Li, W.; Ye, Q.
On the performance of LDPC-RS product codes for mobile DTV

Year: 2012

Abstract: This Conference Paper/Presentation proposes an LDPC-RS product codes for the future terrestrial DTV system, which has to face an increasing demand of high spectrum efficiency and reliability. Particularly, we develop an adaptive decoding algorithm that can switch dynamically according to the SNR of received signals. Our algorithm consists of two key approaches, namely error estimation (EE) and soft value modification (SVM). Simulation results show that our proposed LDPC-RS product codes can correct mixed types of errors (random/burst) and achieve lower BER with less computational complexity. © 2012 IEEE.

Source title: IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, BMSB

DOI: 10.1109/BMSB.2012.6264305

Link: On the performance of LDPC-RS product codes for mobile DTV

Li, Y.; Liu, B.; Rong, B.; Wu, Y.; Gagnon, G.; Gui, L.; Zhang, W.
Compact reconfigurable uwb antenna integrated with stepped impedance stub loaded resonators and switches

Year: 2012

Abstract: A compact reconfigurable antenna integrated with stepped impedance stub (SIS) loaded stepped impedance resonator (SIR) and SIS loaded hexagon stepped impedance resonator (HSIR) for ultra wideband (UWB) applications is proposed in this Conference Paper/Presentation. The reconfigurable UWB antenna can work as a UWB antenna and a dual notch band UWB antenna by controlling the switches ON and OFF. The proposed two notch bands are obtained by embedding a SIS-HSIR on hexagon radiation patch and a SIS-SIR on coplanar waveguide (CPW) excitation line. The reconfigurable characteristic is achieved by means of two ideal switches. The proposed reconfigurable antenna has been designed, fabricated and measured. The experimental results show that the proposed reconfigurable antenna has a multi-mode function and good omni-directional characteristics.

Source title: Progress In Electromagnetics Research C

Series Number: Volume 27 Issue 7

DOI: 10.2528/PIERC12012601

Link: Compact reconfigurable uwb antenna integrated with stepped impedance stub loaded resonators and switches

Li, Y.S.; Li, W.X.; Ye, Q.B.
Low-complexity PAPR reduction algorithm in OFDM systems by designing data subcarriers

Year: 2012

Abstract: This Conference Paper/Presentation proposes an algorithm of data subcarrier designing to apply the tone reservation(TR) peak-to-average power ratio (PAPR) reduction algorithm in OFDM-based wireless communication systems and overcome the high computational cost issue. Different from the existing works, the proposed algorithm focuses on designing data subcarriers, controlling both the iteration times and the number of subcarriers. The new algorithm exhibits similar performance as the traditional TR algorithm with lower computational complexity and the ability to control the number of used subcarriers. Simulation results show that the proposed algorithm can significantly reduce the PAPR by only 2 or 3 iterations. © 2012 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2012.6503869

Link: Low-complexity PAPR reduction algorithm in OFDM systems by designing data subcarriers

Liu, S.; Liu, B.; Ma, X.; Rong, B.; Gui, L.
MIMO-UWB channel characterization within an underground mine gallery

Year: 2012

Abstract: Multiple input multiple output-ultrawide band (MIMO-UWB) systems are experimentally evaluated for underground mine high-speed radio communications. Measurement campaigns using two different antenna configurations have been made in an underground gold mine. Furthermore, two scenarios, which are the line of sight (LoS) and the non-LoS (NLoS), i.e., taking into account the mining machinery effect, are distinguished and studied separately. In fact, the channel is characterized in terms of coherence bandwidth, path loss, shadowing, channel correlation, and capacity. Results reveal how antenna array configuration affects main channel parameters and suggest that mining machinery presence substantially affects both received power and time dispersion parameters within the underground mine and should, therefore, be considered when assessing the performance of in-gallery wireless systems. Moreover, it is shown that the MIMO-UWB takes benefit of the large spreading bandwidth and the multipath propagation environment to increase the channel capacity. © 1963-2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 60 Issue 10

DOI: 10.1109/TAP.2012.2207361

Link: MIMO-UWB channel characterization within an underground mine gallery

Mabrouk, I.B.; Talbi, L.; Nedil, M.; Hettak, K.
Effect of mining machinery on MIMO-UWB radiowave propagation within an underground gallery

Year: 2012

Abstract: In this Conference Paper/Presentation, the characterization of a multiple- input-multiple-output (MIMO) ultrawideband (UWB) propagation channel is reported based on experimental analysis. The wireless channel is measured from 3- to 10-GHz frequency range for a 2 2 MIMO system in an underground mine. The UWB spectrum is divided into subbands (flat fading), and all results are averaged within the 7-GHz bandwidth. Two situations are distinguished and studied separately: the line of sight (LOS), i.e., gallery free of machinery and the non-line-of-sight (NLOS), i.e., machinery obstruction. It is demonstrated that measured K-factors were higher than 1.2 dB and lower than 0.2 dB for LOS and NLOS, respectively. Moreover, the MIMO subchannels have maximum correlation coefficients of 0.69 and 0.65 for LOS and NLOS, respectively. Furthermore, path loss exponent is of a = 1.42 for LOS, however, for NLOS, it is about 3.19. Hence, results suggest that mining machinery presence leads to shadowing and scattering that affect both the received power and time dispersion parameters experienced by the link. Consequently, such presence should be considered when assessing the performance of underground mine gallery wireless systems. The values of these parameters can be used for MIMO-UWB channel modeling. © 2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 60 Issue 11

DOI: 10.1109/TAP.2012.2209859

Link: Effect of mining machinery on MIMO-UWB radiowave propagation within an underground gallery

Mabrouk, I.B.; Talbi, L.; Nedil, M.; Hettak, K.
The effect of the human body on MIMO-UWB signal propagation in an underground mine gallery

Year: 2012

Abstract: This Conference Paper/Presentation studies the effects caused by the presence of a human body on a multiple-input-multiple-output (MIMO) ultrawideband (UWB) communication system. It is very important to study the fading effects caused by the movement of a human body, since these effects become particularly significant when characterizing short-range channels. To address this issue, the wireless channel is measured over 7.5 GHz bandwidth using a 2 × 2 MIMO system in an underground mine containing a human body. Results suggest that human presence substantially affects both path gain and time dispersion parameters experienced by the link. It is demonstrated that larger K-factors (1.6 dB) can be attributed to the high losses associated with reflections caused by a human body, which in turn reduce the strength of the received scattered signal. Consequently, the presence of a mineworker should be considered when assessing the performance of an underground mine gallery wireless system.

Source title: Journal of Electromagnetic Waves and Applications

Series Number: Volume 26 Issue 4

DOI: 10.1163/156939312800030695

Link: The effect of the human body on MIMO-UWB signal propagation in an underground mine gallery

Mabrouk, I.B.; Talbi, L.; Nedil, M.; Hettak, K.
Fault detection in MANETs

Year: 2012

Abstract: Node faults may be frequent in a mobile ad hoc network (MANET). Most work related to fault detection and localization for MANETS essentially use changes in topology to identify faults. Most of this work does not distinguish between node movement that results in a functioning node moving out of range of all other nodes versus a node that crashes as the result of a radio transmitter malfunctioning or a battery no longer operating. This Conference Paper/Presentation introduces a novel protocol that makes this distinction. Nodes forward their neighbourhood observations to a cluster head. The cluster head uses this to determine a list of suspected crashed nodes and sends this list to all the other nodes to filter out those nodes that have moved out of range. The cross-layer implementation of the protocol is effective in distinguishing between crashed nodes and nodes that have moved out of range. © 2012 IEEE.

Source title: Proceedings of the 2012 IEEE Network Operations and Management Symposium, NOMS 2012

DOI: 10.1109/NOMS.2012.6211981

Link: Fault detection in MANETs

Mamun, W.A.; Lutfiyya, H.; Kidston, D.; Li, L.
Rendering unto Cæsar the things that are Cæsar's: Complex trust models and human understanding

Year: 2012

Abstract: In this position Conference Paper/Presentation we examine some of the aspects of trust models, deployment, use and 'misuse,' and present a manifesto for the application of computational trust in sociotechnical systems. Computational Trust formalizes the trust processes in humans in order to allow artificial systems to better make decisions or give better advice. This is because trust is flexible, readily understood, and relatively robust. Since its introduction in the early '90s, it has gained in popularity because of these characteristics. However, what it has oftentimes lost is understandability. We argue that one of the original purposes of computational trust reasoning was the human element - the involvement of humans in the process of decision making for tools, importantly at the basic level of understanding why the tools made the decisions they did. The proliferation of ever more complex models may serve to increase the robustness of trust management in the face of attack, but does little to help mere humans either understand or, if necessary, intervene when the trust models fail or cannot arrive at a sensible decision. © 2012 IFIP International Federation for Information Processing.

Source title: IFIP Advances in Information and Communication Technology

Series Number: Volume 374 AICT

DOI: 10.1007/978-3-642-29852-3_13

Link: Rendering unto Cæsar the things that are Cæsar's: Complex trust models and human understanding

Marsh, S.; Basu, A.; Dwyer, N.
Non-standards for trust: Foreground trust and second thoughts for mobile security

Year: 2012

Abstract: In this Conference Paper/Presentation, we introduce and discuss Foreground Trust. Foreground Trust, itself based on recent work in the area of Trust Enablement, is a paradigm for allowing devices in a human-device ecosystem the means to reason with and about trust in themselves, other devices, and humans, whilst allowing humans to make trusting decisions using their own internal models (whatever they may be) based on cues from the environment - including the device(s) in use at the time. We discuss the paradigm, and present an actualization of it in the form of Device Comfort, a model of device reasoning based on environmental cues, and the use of the device status to help users make informed trusting and security decisions for themselves. In particular we focus on the interface between user and device to help the user make trust-based decisions and use second thoughts as a means to educate and raise user awareness about their security in online and mobile behaviours. © 2012 Springer-Verlag Berlin Heidelberg.

Source title: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Series Number: Volume 7170 LNCS

DOI: 10.1007/978-3-642-29963-6_4

Link: Non-standards for trust: Foreground trust and second thoughts for mobile security

Marsh, S.; Noel, S.; Storer, T.; Wang, Y.; Briggs, P.; Robart, L.; Stewart, J.; Esfandiari, B.; El-Khatib, K.; Vefa Bicakci, M.; Cuong Dao, M.; Cohen, M.; Da Silva, D.
A testing model for dynamic malware analysis systems

Year: 2012

Abstract: A Dynamic Malware Analysis System (D-MAS), often called a sandbox, is a controlled environment in which malicious software (malware) is executed in order to identify the actions it is performing (e.g., creating processes, sending emails) when infecting computer systems. One of the most important features of security devices such as IDSs, AVSs and D-MASs, is how accurately they identify and document threats. By nature, these security devices are difficult to test since they are test systems themselves. The attackers are the testers trying to find test cases that cannot be identified by these systems. Consequently, thorough testing models are required by developers to assess the accuracy of D-MASs, an area in which very little theoretical and empirical work exists. In this Conference Paper/Presentation, we lay out the basis of D-MASs accuracy assessment and we present an evaluation of eight of these systems. We propose test coverage criteria, oracle types and specifications to assess the accuracy of D-MASs. Results show that our approach is efficient at identifying accuracy problems in several D-MASs. © 2012 IEEE.

Source title: Proceedings - IEEE 5th International Conference on Software Testing, Verification and Validation, ICST 2012

DOI: 10.1109/ICST.2012.183

Link: A testing model for dynamic malware analysis systems

Massicotte, F.; Couture, M.; Normandin, H.; Michaud, F.
Design of 15 dB directional coupler using substrate-integrated waveguide technology

Year: 2012

Abstract: A 15-dB directional coupler is designed and fabricated using the substrate-integrated waveguide (SIW) technique and Bethe's holes method (BHM).The proposed design is a perfect candidate for design of highly integrated microwave and millimeter-wave circuits. Three holes with optimized radius are positioned on the conducting wall to achieve the desired coupling operating at X-band. A good agreement between experimental and simulation results is obtained. © 2012 Wiley Periodicals, Inc.

Source title: Microwave and Optical Technology Letters

Series Number: Volume 54 Issue 4

DOI: 10.1002/mop.26678

Link: Design of 15 dB directional coupler using substrate-integrated waveguide technology

Mbaye, M.; Talbi, L.; Hettak, K.; Kabiri, A.
Fiber bragg grating sensors for harsh environments

Year: 2012

Abstract: Because of their small size, passive nature, immunity to electromagnetic interference, and capability to directly measure physical parameters such as temperature and strain, fiber Bragg grating sensors have developed beyond a laboratory curiosity and are becoming a mainstream sensing technology. Recently, high temperature stable gratings based on regeneration techniques and femtosecond infrared laser processing have shown promise for use in extreme environments such as high temperature, pressure or ionizing radiation. Such gratings are ideally suited for energy production applications where there is a requirement for advanced energy system instrumentation and controls that are operable in harsh environments. This Conference Paper/Presentation will present a review of some of the more recent developments. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Source title: Sensors

Series Number: Volume 12 Issue 2

DOI: 10.3390/s120201898

Link: Fiber bragg grating sensors for harsh environments

Mihailov, S.J.
Orthogonally-polarized dual-band MEMS-tunable double-slotted unit cell for reflectarray applications

Year: 2012

Abstract: This Conference Paper/Presentation presents a single-layer MEMS-reconfigurable reflective unit cell that supports two bands (12 and 14 GHz) at two orthogonal polarizations. A pair of MEMS varactors is used for continuous and independent tuning of each band. The dynamic phase range of 310 degree is obtained with a maximum loss of 0.23 dB. The resultant reflectarray can have a separate scanned beam of given polarization at each of its two operating frequency bands. This unit cell has the requirements of Cognitive Radio and Satellite two-way communication.

Source title: Antennas and Propagation Society International Symposium (APSURSI), 2012 IEEE

DOI: 10.1109/APS.2012.6347988

Link: Orthogonally-polarized dual-band MEMS-tunable double-slotted unit cell for reflectarray applications

Moghadas, H.; Daneshmand, M.; Mousavi, P.; Chaharmir, M.R.; Shaker, J.
Impact of feed position on the operating band of broadband reflectarray antenna

Year: 2012

Abstract: In this letter, the effect of moving the feed on the operation bandwidth of a broadband reflectarray is investigated through simulation and measurement. A new broadband cell element with optimized dimensions to achieve linear phase shift is proposed in this investigation. A square reflectarray of 40 × 40 cm2 comprising this particular unit cell was designed and fabricated to demonstrate wideband operation at X-Ku band. The effect of feed movement on the operating band was studied by exciting the reflectarray with a plane wave and monitoring the near field on the line passing through the assumed feed locations over a wide frequency band. Considering three different feed positions, the reflectarray was simulated, and good agreement between simulated and measured results was observed. It is shown that changing the feed location leads to a considerable shift in operating frequency window of the reflectarray and also its maximum gain, which gives rise to the possibility of changing the operating band without redesigning the reflectarray by only moving the feed. Moreover, a remarkable value of 36% of 1.5 dB gain-bandwidth was measured, which is higher compared to previously reported designs in the literature. © 2012 IEEE.

Source title: IEEE Antennas and Wireless Propagation Letters

Series Number: Volume 11

DOI: 10.1109/LAWP.2012.2218563

Link: Impact of feed position on the operating band of broadband reflectarray antenna

Mohammadirad, M.; Komjani, N.; Chaharmir, M.R.; Shaker, J.; Sebak, A.R.
All-pole modeling of discrete spectral powers: A unified approach

Year: 2012

Abstract: In this correspondence, a unified approach to the autoregressive (AR) modeling of power spectral densities is described. We show that by introducing auxiliary sequences, the minimization of several customary spectral distances can be performed with the exact same convenient approach, whether a gradient-descent or a Newton/quasi-Newton descent is chosen. Moreover, we extend the usual optimization of unnormalized AR coefficients to a two-step optimization of normalized AR coefficients, and provide evidence that this alternative approach can accelerate convergence and provide robustness to erroneous initializations. Convergence and modeling results are also given. © 2011 IEEE.

Source title: IEEE Transactions on Audio, Speech and Language Processing

Series Number: Volume 20 Issue 2

DOI: 10.1109/TASL.2011.2163511

Link: All-pole modeling of discrete spectral powers: A unified approach

Mustiere, F.; Bouchard, M.; Bolic, M.
Towards reliable cooperative communications in clustered ad hoc networks

Year: 2012

Abstract: Node clustering has been considered as a promising approach in ad hoc networks, where the inter cluster routing is limited to some special nodes called cluster head (CH). In practice, the performance of data transmission often degrades with the increase of distance between neighboring CHs. This Conference Paper/Presentation proposes a new scheme that employs intermediate nodes as relays between neighboring CHs. Particularly, we develop both feedback and non-feedback fountain coded cooperative communications to improve reliability and robustness. It is observed that the number of relays plays a significant role in our scheme. Accordingly, we design a rateless coded relay selection (RCRS) algorithm to guarantee the required data rate with a minimum cost. Simulation results show that feedback based protocol outperforms its non-feedback counterpart in terms of end to end rate and throughput. © 2012 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2012.6503757

Link: Towards reliable cooperative communications in clustered ad hoc networks

Nessa, A.; Kadoch, M.; Hu, R.Q.; Rong, B.
Impact of mobility on trust decay rate

Year: 2012

Abstract: In trust-based models for MANETs, it is often assumed that the trust value between two nodes decays proportional to the time these nodes are out of transmission range of each other. We present in this Conference Paper/Presentation an analysis of the trust decay rate for some general networking and trust computation models. Our analysis allows for the consideration of the subjective trust values assigned by present and past neighbours within a given history timeframe. The mobility models being studied in this Conference Paper/Presentation include random way point (RWP) and random walk (RW). This analysis exhibits the impact of mobility on the trust decay rate. Simulations are used to confirm the accuracy of analytical results and shed light on some interesting facts such as the slow decay of globally computed trust values, even if fast subjective trust decay functions (linear and exponential) are employed, or the weak impact of the network density on the trust decay rate. © 2012 IEEE.

Source title: IEEE Wireless Communications and Networking Conference, WCNC

DOI: 10.1109/WCNC.2012.6214288

Link: Impact of mobility on trust decay rate

Nguyen, D.Q.; Kunz, T.; Lamont, L.
Optimizing the monitoring path design for independent dual failures

Year: 2012

Abstract: This Conference Paper/Presentation proposes a new monitoring path design paradigm for independent dual link failures. Specifically, the new approach exploits the sequential arrival and departure property of independent failure events to uniquely localize failed links. Such property, however, cannot be captured by the existing approach, which is built upon the notion of shared risk link groups. Consequently, we show via solution space comparison that the existing approach can result in overdesign in terms of monitoring resources required. Numerical results further indicate that the new approach outperforms the existing one in terms of monitoring cost and computational efficiency. © 2012 IEEE.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2012.6364269

Link: Optimizing the monitoring path design for independent dual failures

Ni, W.; Huang, C.; Wu, J.; Li, Q.; Savoie, M.
Flow availability analysis in two-layer networks with dedicated path protection at the upper layer

Year: 2012

Abstract: We propose an analytical model that computes availability of upper-layer flows in two-layer networks with dedicated path protection deployed at the upper layer. Our proposed model reduces overestimation of the existing model caused by the ignorance of upper-layer failure correlations. We compute the flow availability by properly taking into account such correlation, and tracing upper-layer failures to lower-layer root causes. Our simulation results show that our proposed model reduces overestimation on upper-layer flow unavailability by about 30%, and thus significantly relaxes unnecessary high-availability requirements on lower-layer links without compromising the availability of upper-layer flows. © 2012 IEEE.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2012.6364266

Link: Flow availability analysis in two-layer networks with dedicated path protection at the upper layer

Ni, W.; Wu, J.; Huang, C.; Savoie, M.
Preference-oriented QoS-based service discovery with dynamic trust and reputation management

Year: 2012

Abstract: In the presence of a variety of service providers that offer web services with overlapping or identical functionality, service consumers need a mechanism to distinguish one service from another based on their own subjective quality of service (QoS) preferences. Typical approaches in this field rely on trusted third parties to monitor the behaviour of service providers and endorse their performance based on their delivered services to different users. However, the issue of evaluating the credibility of user reports is one of the essential problems yet to be solved in the e-Business application area. In this Conference Paper/Presentation we propose a two-layered preference-oriented service selection framework that integrates trust and reputation management techniques with an advanced procurement auction model in order to choose the most pertinent service provider that meets a consumer's QoS requirements. We will give a formal description of our approach and validate it with experiments demonstrating that our solution yields high-quality results under various realistic circumstances. © 2012 ACM.

Source title: Proceedings of the ACM Symposium on Applied Computing

DOI: 10.1145/2245276.2232111

Link: Preference-oriented QoS-based service discovery with dynamic trust and reputation management

Noorian, Z.; Fleming, M.; Marsh, S.
A strategic reputation-based mechanism for mobile ad hoc networks

Year: 2012

Abstract: Mobile ad hoc networks (MANETs) are formed by a set of mobile nodes without relying on a preexisting infrastructure. In MANETs, ad hoc nodes should count on intermediate nodes to relay messages between two distant nodes. However, due to the inherent dynamicity of such networks, secure and reliable packet forwarding is difficult to achieve. Besides, considering the scarcity of nodes' power and computational resources, different nodes might find it economically rational to act selfishly in order to maximize their own welfare during their lifecycle. Therefore, in order to keep the network functional we need a mechanism to enforce nodes' contribution to network operations despite their internal characteristics and willingness. In this Conference Paper/Presentation we propose a reputation-based schema to foster cooperation amongst ad hoc nodes in the packet forwarding game and isolate selfish behaviours within the MANETs. In the proposed approach, each node is equipped with a security mechanism to estimate the credibility of its neighbouring nodes as well as adaptive measures to compute the cooperation and defection payoffs in order to strategically choose the most profitable behaviour toward its partners. Experimental results indicate the efficacy of our approach in identifying selfish nodes and promote the adoption of a strategic behaviour determination mechanism in a dynamic network in which different nodes with conflicting tendencies participate. © 2012 Springer-Verlag.

Source title: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Series Number: Volume 7310

DOI: 10.1007/978-3-642-30353-1_13

Link: A strategic reputation-based mechanism for mobile ad hoc networks

Noorian, Z.; Noorian, M.; Fleming, M.; Marsh, S.
Determining the optimal reporting strategy in competitive E-marketplaces

Year: 2012

Abstract: In a reputation system for multiagent based electronic marketplaces where the number of high quality products provided by good selling agents is unlimited, buying agents often share seller information without the need to consider possible utility loss. However, when those good sellers have limited inventory, buyers may have to be concerned about the possibility of losing the opportunity to do business with the good sellers if the buyers provide truthful information about sellers, due to the competition from other buyers. In this Conference Paper/Presentation, we propose an adaptive mechanism built on a game theoretic basis for buyers to determine their optimal reputation reporting strategy, by modeling both the competency and willingness of other buyers in reporting seller reputation and strategically choosing reporting behaviours that maximize their utility according to the modeling results. The results of the experiments carried out in a simulated competitive e-marketplace confirm that our proposed mechanism leads to better utility for buyers in such an environment. © 2012 IEEE.

Source title: Proc. of the 11th IEEE Int. Conference on Trust, Security and Privacy in Computing and Communications, TrustCom-2012 - 11th IEEE Int. Conference on Ubiquitous Computing and Communications, IUCC-2012

DOI: 10.1109/TrustCom.2012.125

Link: Determining the optimal reporting strategy in competitive E-marketplaces

Noorian, Z.; Zhang, J.; Fleming, M.; Marsh, S.
Loudness normalization of wide-dynamic range broadcast material

Year: 2012

Abstract: Various techniques are being used by broadcasters to normalize the loudness levels of their programmes. For longform content, EBU R128 recommends that the full programme be measured using the algorithm described in ITU-R BS.1770-2. ATSC A/85 recommends instead that only the "Anchor Element" of long-form content need be measured. For narrow dynamic range material, the differences between the two measures are not large, but there can be large differences between the two approaches when the material has a wide dynamic range. This Conference Paper/Presentation compares these two measurement approaches and explores their subjective consequences.

Source title: 132nd Audio Engineering Society Convention 2012

DOI: N/A

Link: Loudness normalization of wide-dynamic range broadcast material

Norcross, S.G.; Lavoie, M.C.
Evaluation of VeMAC for V2V and V2R communications under unbalanced vehicle traffic

Year: 2012

Abstract: A vehicular ad hoc network (VANET) is an emerging technology which has a great potential of new applications in safety, traffic optimization, and entertainment. The VeMAC [1], [2] is a medium access control protocol recently proposed for VANETs, which can support efficient broadcast service necessary for high priority safety applications. The VeMAC protocol reserves disjoint sets of time slots to vehicles moving in opposite directions and to road side units (RSUs). The protocol has been evaluated for vehicle-to-vehicle (V2V) communications and under balanced vehicle traffic conditions, in which the densities of vehicles moving in opposite directions on a two-way road are approximately equal [2]. In this Conference Paper/Presentation we investigate the effects of the existence of RSUs and the unbalanced vehicle traffic conditions on the VeMAC performance, via simulations in highway and city scenarios in terms of network throughput and transmission collision rate. © 2012 IEEE.

Source title: IEEE Vehicular Technology Conference

DOI: 10.1109/VTCFall.2012.6398905

Link: Evaluation of VeMAC for V2V and V2R communications under unbalanced vehicle traffic

Omar, H.A.; Zhuang, W.; Li, L.
Implementation of a 700 mhz tvws technology based on IEEE 802.11b (Wi-Fi)

Year: 2012

Abstract: A segment of the TV spectrum at 700 MHz has been vacated as a result of the transition of TV from analog to digital. Consequently, new applications are being proposed for these bands [1]. Named TV White Space (TVWS), the longer transmission ranges and better propagation characteristics of TVWS makes it ideal for long range communications. Currently, 2.4 GHz Wi-Fi technologies are used for rural applications [2], however they suffer limitations due to propagation loss. Since the 700 MHz band has better propagation, long range links at this frequency band are expected to perform better. Using 700 MHz Wi-Fi radios (called XR7) from Ubiquiti Networks [3], we undertook a development to deploy and test a long-range Wi-Fi relay link operating in the TVWS band. The primary goal of our experiment was to study the backhaul performance and propagation characteristics of the link and demonstrate the viability of a concept that uses Wi-Fi operating in the TVWS; which is an objective of the developing standard called IEEE 802.11af [4]. This Conference Paper/Presentation discusses the setup and performance results of our experimental link and some of the compliance issues faced by Wi-Fi operating in the TVWS bands.

Source title: Proceedings of the IASTED International Conference on Wireless Communications, WC 2012

DOI: 10.2316/P.2012.784-018

Link: Implementation of a 700 mhz tvws technology based on IEEE 802.11b (Wi-Fi)

Palaninathan, S.; Sydor, J.
Augmented data transmission based on low density parity check code for the ATSC terrestrial DTV system

Year: 2012

Abstract: In this Conference Paper/Presentation, we propose a novel augmented data transmission (ADT) system based on low density parity check (LDPC) code for an additional data stream transmission in the Advanced Television Systems Committee (ATSC) terrestrial digital television system. The LDPC code-based ADT system can provide additional data of rate up to 3 megabits per second (Mbps), which is significantly improved over the conventional data transmission schemes used in the transmitter identification system. Based on the laboratory test, we verify that the LDPC code-based ADT system is only about 1.1 dB away from Shannon limit. © 2012 IEEE.

Source title: IEEE Transactions on Broadcasting

Series Number: Volume 58 Issue 4

DOI: 10.1109/TBC.2012.2217011

Link: Augmented data transmission based on low density parity check code for the ATSC terrestrial DTV system

Park, S.I.; Kim, H.M.; Wu, Y.; Kim, J.
Augmented data transmission for the ATSC terrestrial DTV system

Year: 2012

Abstract: In this paper, we propose an Augmented Data Transmission (ADT) system which can transmit an additional data stream in the ATSC terrestrial DTV system. The proposed ADT system can offer an additional data of rate up to a few Mbps based on hierarchical modulation, DTV signal cancellation, and advanced error correction code. Since the proposed ADT system uses the in-band hierarchical modulation, it does not require any additional RF spectrum to increase the data capacity in a 6 MHz RF channel.

Source title: 2012 IEEE International Conference on Consumer Electronics (ICCE)

DOI: 10.1109/ICCE.2012.6161870

Link: Augmented data transmission for the ATSC terrestrial DTV system

Park, S.I.; Lim, H.; Kim, H.M.; Wu, Y.; Oh, W.
An overview of tuning techniques for frequency-agile antennas

Year: 2012

Abstract: Frequency-agile antennas can be designed to switch between a set of discrete frequencies, or to be tuned over a continuous range of frequencies. Methods for achieving discrete or continuous frequency tuning can be grouped into three categories: mechanical actuation, tunable materials, and integrated electronic devices. Example tuning techniques in each class are presented, highlighting strengths and weaknesses of each method. © 1990-2011 IEEE.

Source title: IEEE Antennas and Propagation Magazine

Series Number: Volume 54 Issue 5

DOI: 10.1109/MAP.2012.6348178

Link: An overview of tuning techniques for frequency-agile antennas

Petosa, A.
An overview of recent antennas and propagation research activities in Canada

Year: 2012

Abstract: A survey of recent antennas and propagation research activities in Canada has been carried out. Lists of the main research institutes and research areas are provided, along with a more detailed examination of a few selected topics, to illustrate Canadian contributions to these fields. © 2011 IEEE.

Source title: IEEE Antennas and Propagation Magazine

Series Number: Volume 54 Issue 6

DOI: 10.1109/MAP.2012.6387847

Link: An overview of recent antennas and propagation research activities in Canada

Petosa, A.
Spatio-temporal channel characterization: Theoretical framework and applications in MIMO system design

Year: 2012

Abstract: The utilization of multiple antennas and space-time codes in multiple-input and multipleoutput (MIMO) communication systems significantly improves the transmission channel capacity without using additional bandwidth and power. The improvement is achieved by decomposing the spatial structure of transmission channels and performing appropriate temporal and spatial multiplexing. In this Conference Paper/Presentation, we propose a novel theoretical framework for MIMO channel modeling and characterization in order to facilitate the MIMO system design and performance evaluation. The channels are represented in space, time, wave vector, and frequency domains while the space-time and wave vector-frequency interdependences are considered. A realization of the theoretical framework, in a form of a practical framework, is also proposed to address the channel modeling and characterization at both transmitter and receiver sides. The utilization of the practical framework in MIMO communication system design is discussed to illustrate its applications in realistic scenarios. The angle of arrival estimation based on the proposed practical framework using field test measurement data is also presented as illustrative examples. © Institut Télécom and Springer-Verlag 2011.

Source title: Annales des Telecommunications/Annals of Telecommunications

Series Number: Volume 67 Issue 1

DOI: 10.1007/s12243-011-0248-9

Link: Spatio-temporal channel characterization: Theoretical framework and applications in MIMO system design

Pham, V.-H.; Chouinard, J.-Y.; Grenier, D.; Huynh, H.-T.; Wang, X.; Wu, Y.
Toward the probabilistic forecasting of high-latitude GPS phase scintillation

Year: 2012

Abstract: The phase scintillation index was obtained from L1 GPS data collected with the Canadian High Arctic Ionospheric Network (CHAIN) during years of extended solar minimum 2008-2010. Phase scintillation occurs predominantly on the dayside in the cusp and in the nightside auroral oval. We set forth a probabilistic forecast method of phase scintillation in the cusp based on the arrival time of either solar wind corotating interaction regions (CIRs) or interplanetary coronal mass ejections (ICMEs). CIRs on the leading edge of high-speed streams (HSS) from coronal holes are known to cause recurrent geomagnetic and ionospheric disturbances that can be forecast one or several solar rotations in advance. Superposed epoch analysis of phase scintillation occurrence showed a sharp increase in scintillation occurrence just after the arrival of high-speed solar wind and a peak associated with weak to moderate CMEs during the solar minimum. Cumulative probability distribution functions for the phase scintillation occurrence in the cusp are obtained from statistical data for days before and after CIR and ICME arrivals. The probability curves are also specified for low and high (below and above median) values of various solar wind plasma parameters. The initial results are used to demonstrate a forecasting technique on two example periods of CIRs and ICMEs. © 2012. American Geophysical Union. All Rights Reserved.

Source title: Space Weather

Series Number: Volume 10 Issue 8

DOI: 10.1029/2012SW000800

Link: Toward the probabilistic forecasting of high-latitude GPS phase scintillation

Prikryl, P.; Jayachandran, P.T.; Mushini, S.C.; Richardson, I.G.
Guided sampling in multiple view robust motion estimation using regression diagnostics

Year: 2012

Abstract: Random Sampling Consensus (RANSAC) is a standard tool in various estimation problems in computer vision. This Conference Paper/Presentation presents an improvement to RANSAC where regression diagnostics information is incorporated in RANSAC in order to improve accuracy and speed. The improvement in the sampling stage speeds up the estimation by taking advantage of a priori information driven from regression diagnostics. Also, a new stopping criterion is presented that enables a much higher speed in the estimation process and guarantees that the iterative estimation is stopped as soon as the best model is found. In addition, the proposed method can easily be combined with existing randomized hypothesis verification techniques to achieve an even higher accuracy and speed. The algorithm is tested extensively on synthetic data and the results show a marked improvement in the accuracy of the estimation and a speed up of more than three times over the traditional RANSAC. © 2012 Springer-Verlag.

Source title: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Series Number: Volume 7431 LNCS Part 1

DOI: 10.1007/978-3-642-33179-4_14

Link: Guided sampling in multiple view robust motion estimation using regression diagnostics

Rastgar, H.; Dubois, E.; Zhang, L.
Propagation Impairments for Arctic Satellite Telecommunication Systems

Year: 2012

Abstract: The most important propagation impairments for future satellite telecommunication applications in the Arctic are reviewed.

Source title: 18th Ka and Broadband Communications and 30th AIAA International Communications Satellite Systems Conference (ICSSC) Joint Conference, Ottawa, Canada

DOI: N/A

Link: Propagation Impairments for Arctic Satellite Telecommunication Systems

Rogers, D.;  Bouchard, P.
Exploring controllable deterministic bits for LDPC iterative decoding in WiMAX networks

Year: 2012

Abstract: Low-density parity-check (LDPC) codes are playing an important role in modern wireless communication systems such as WiMAX due to their Shannon limit approaching error correction performance. To lower the decoding threshold of LDPC codes, this Conference Paper/Presentation develops a novel multi-layer iterative decoding scheme using deterministic bits for multimedia communication systems. These deterministic bits serve as known information in the LDPC decoding process to reduce the redundancy during data transmission. Unlike the existing work, our proposed scheme addresses the controllable deterministic bits, such as MPEG null packets, rather than the widely investigated protocol headers. Simulation results show that our proposed scheme can achieve considerable gain in WiMAX networks. © 2012 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2012.6503745

Link: Exploring controllable deterministic bits for LDPC iterative decoding in WiMAX networks

Rong, B.; Xu, Y.; Wu, Y.; Gagnon, G.; Liu, B.; Gui, L.; Zhang, W.
On using a closed box as the integration surface with the FDTD method

Year: 2012

Abstract: This Conference Paper/Presentation disproves an hypothesis that this author had made in an earlier Conference Paper/Presentation from the observation that the values of the plane wave scattering coefficients computed with his numerical method could vary substantially with the physical separation distance between the integration box and the scatterer enclosed within the box. This variation was observed when the edges and corners of the integration box were strongly illuminated with the scattered field. It was hypothesized that this variation was due to the use of a box as the integration surface because a box is not the smooth integration surface that is supposed to be needed for the application of Huygens' principle on which is based the computation of the far-field values with the steady-state near-to-far field transformation. In this Conference Paper/Presentation, it is found by reconstructing the spatial field distribution that corresponds to the error spectrum, and noting that this distribution is not confined to the edges and corners of the integration box, that the use of the box is not the cause for the variation and thus, that the hypothesis is false. It turned out that the variation nearly disappeared when the FDTD mesh size was of the order of 100 cells per wavelength. It is shown that the variation was due to the second-order accuracy of the FDTD stencil. © 2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 60 Issue 5

DOI: 10.1109/TAP.2012.2189744

Link: On using a closed box as the integration surface with the FDTD method

Roy, J.E.
A new CPSS element

Year: 2012

Abstract: This Conference Paper/Presentation presents the performance of a new Circular Polarization Selective Surface (CPSS) that has the 2-fold rotational symmetry that is theoretically required for an improved performance under oblique incidence. Comparison between the simulation results for Pierrot's CPSS design that does not have that symmetry, and the results for the new design shows the improved performance of the new design. Further improvement comes from optimizing the inter-element spacing. © 2012 IEEE.

Source title: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest)

DOI: 10.1109/APS.2012.6348732

Link: A new CPSS element

Roy, J.E.
A trust distribution service for MANETs

Year: 2012

Abstract: Mobile ad hoc networks (MANETs) are very useful for communications in areas with very little or no infrastructure. However, that very lack of an authoritative management infrastructure makes it imperative that nodes cooperate by passing traffic fairly and securely. The use of a reputation or trust management system can identify failed, misbehaving or malicious nodes. One aspect of trust management that has been relatively overlooked is the trust distribution service. In this Conference Paper/Presentation, we use a trust model that uses local observations from all nodes in the network to calculate per-node reputation using a trust matrix. We have developed a gossip-based distribution service that reduces network-wide reputation convergence time by prioritising critical trust updates. Simulations show that this distribution service substantially outperforms naïve gossip and provides insight into optimal node density for epidemic-based routing schemes in resource constrained networks. © 2012 IEEE.

Source title: IEEE Vehicular Technology Conference

DOI: 10.1109/VTCFall.2012.6399335

Link: A trust distribution service for MANETs

Rutagemwa, H.; Kidston, D.
Cross-layer modeling and analysis of multihop tactical networking in convoy topology

Year: 2012

Abstract: In this Conference Paper/Presentation, we develop a framework for studying the performance of guaranteed and best-effort data delivery services over wireless tactical networks with multiple relays and multiple clusters. In particular, we apply the analysis technique to a convoy topology and incorporate practical models for narrowband VHF radios and propagation to evaluate the network performance. The numerical results have demonstrated the performance tradeoffs between throughput and efficiency/robustness over a wide range of radio modes and network configurations. These results lead to approaches for wireless networking optimized for tactical radios in terrestrial environments. © 2012 IEEE.

Source title: Proceedings - IEEE Military Communications Conference MILCOM

DOI: 10.1109/MILCOM.2012.6415788

Link: Cross-layer modeling and analysis of multihop tactical networking in convoy topology

Rutagemwa, H.; Li, L.; Vigneron, P.
Sound-localization-preserved binaural MMSE STSA estimator with explicit and implicit binaural cues

Year: 2012

Abstract: In this Conference Paper/Presentation, we address some variations of the source-localization- preserved MMSE STSA estimator used for binaural hearing aids. In our previous work, the sound-localization-preserved MMSE STSA estimator with ICA-based noise estimation has been proposed. However, this conventional method is based on an approximated optimization criterion and does not use binaural cues, resulting in poor noise reduction performance. To solve this problem, we propose two methods: a multichannel MMSE STSA estimator with explicit binaural cues, and a sound-localization-preserved generalized MMSE STSA estimator with different speech priors for the left and right channels as implicit bin-aural cues. From the results of objective and subjective evaluation, we confirm that the noise reduction performance is improved using the proposed method. © 2012 EURASIP.

Source title: European Signal Processing Conference

DOI: N/A

Link: Sound-localization-preserved binaural MMSE STSA estimator with explicit and implicit binaural cues

Saruwatari, H.; Wakisaka, R.; Shikano, K.; Mustiere, F.; Thibault, L.; Najaf-Zadeh, H.; Bouchard, M.
MMIC Doherty power amplifier for a 5W pico-cell base station in GaN HFET technology

Year: 2012

Abstract: 4G standards such as Long Term Evolution (LTE) use non-constant envelope modulation techniques with high peak-to-average ratios. Power amplifiers (PA) implemented in such applications are forced to operate at a backed-off region from saturation. Thus, to reduce power consumption, a design of a high efficiency PA that can maintain the efficiency for a wider range of RF signals is required. In this Conference Paper/Presentation, a two-way 10W Doherty amplifier designed in a compact 10 × 11.5mm2 monolithic microwave integrated circuit using GaN technology is presented. Suitable for a 4G LTE 5W pico-cell base station, which entails the frequencies from 2.62-2.69GHz, the design achieves high efficiencies of over 50% at both back-off and peak power regions without compromising on the stringent linearity requirements of 4G LTE standards. This demonstrates a 17% increase in power added efficiency at 6 dB back-off from peak power compared to conventional Class AB amplifier performance. © 2012 IEEE.

Source title: Proceedings of the International Conference on Microelectronics, ICM

DOI: 10.1109/ICM.2012.6471411

Link: MMIC Doherty power amplifier for a 5W pico-cell base station in GaN HFET technology

Seneviratne, S.G.; Yagoub, M.C.E.; Amaya, R.E.
Numerical investigation of EBG structures composed of rings

Year: 2012

Abstract: The results of extensive numerical investigation is presented in order the gain a better understanding of the behavior of EBG structure composed of open square rings. Presence of the gap in the cell element of such Electromagnetics Bandgap (EBG) structure renders the structure sensitive to the orientation of the constituent ring elements. It is shown that the bandgap persists for both orthogonal orientations of the open square ring. Also, it is demonstrated through numerical simulations that it is feasible to realize slab EBG configuration comprised of open square rings. © 2012 IEEE.

Source title: 2012 15th International Symposium on Antenna Technology and Applied Electromagnetics, ANTEM 2012

DOI: 10.1109/ANTEM.2012.6262309

Link: Numerical investigation of EBG structures composed of rings

Shaker, J.; Chaharmir, M.R.
ALTERNATIVE MEASURE OF PERFORMANCE FOR SATELLITE LINKS EMPLOYING ADAPTIVE CODING AND MODULATION

Year: 2012

Abstract: An alternative measure of performance on a digital satellite link is proposed which is termed "fractional degradation in information rate"; a measure normalized to the highest available information rate. It is believed that this measure may be useful when describing the effective throughput (or loss of throughput) for satellite links employing Adaptive Coding and Modulation (ACM). Satellite links employing constant coding and modulation (CCM) are typically designed for an availability objective. For satellite links which employ ACM, every possible combination of modulation and coding will have associated with it a probability of being implemented. It is meaningful when describing the performance of a link employing CCM as having an availability equal to the percentage of time in which the received signal performs at or better than a threshold Bit-Error-Rate (BER). For a link employing ACM, however, it is less obvious what the performance is when the information rate available on the link is the highest during clear-sky or near clear-sky conditions, but at a reduced rate when additional impairments on the signal path exist. It is proposed that for applications where a reduction in information rate is not critical, but the long-term average level of throughput is more important, a clear methodology for calculating the long-term average throughput be used. Using this methodology on satellite links employing ACM will allow the calculated performance of satellite links to be compared in an unambiguous manner. Ultimately, it is proposed that long-term average throughput be used as a design objective for links employing ACM.

Source title: 30th AIAA International Communications Satellite Systems Conference (ICSSC) Conference

Series Number: Volume 1 Issue 1

DOI: 10.2514/6.2012-15069

Link: ALTERNATIVE MEASURE OF PERFORMANCE FOR SATELLITE LINKS EMPLOYING ADAPTIVE CODING AND MODULATION

Shewan, G.
Intrusion Detection in Tactical Mobile Ad Hoc Networks Using Game Theory

Year: 2012

Abstract: Tactical Mobile Ad hoc Networks (MANETs) are suitable for military communication scenarios where fixed infrastructure is not available.  However, in such cases, the environment is especially hostile in terms of impaired wireless channels and the possible existence of malicious devices.  In this paper, we propose the use of a game theoretic solution to identify malicious nodes that can correct for the impact of the lossy wireless channel.  The results demonstrate that the improved observation fidelity generates fewer false positive alarms and thus reduces the impact of attack from malicious node(s).

Source title: NATO Symposium IST-111/ RSY-026

DOI: N/A

Link: Intrusion Detection in Tactical Mobile Ad Hoc Networks Using Game Theory

Shi, M.; Li, L.; Kidston, D.; Mason, P.
Temperature stability in silica based Fiber Bragg gratings

Year: 2012

Abstract: Fiber Bragg gratings (FBG) have garnered interest as temperature and strain sensors because they are compact, inexpensive, and can be utilised for distributed and multi-parameter sensing. Ultrafast laser induced FBGs have been shown be especially promising for higher temperature (>500 °C) applications. In this presentation we will discuss our most recent measurements of ultrafast gratings at elevated temperatures. © 2012 SPIE.

Source title: Proceedings of SPIE - The International Society for Optical Engineering

Series Number: Volume 8257

DOI: 10.1117/12.909617

Link: Temperature stability in silica based Fiber Bragg gratings

Smelser, C.W.; Mihailov, S.J.; Grobnic, D.
Staircase codes: FEC for 100 Gb/s OTN

Year: 2012

Abstract: Staircase codes, a new class of forward-error-correction (FEC) codes suitable for high-speed optical communications, are introduced. An ITU-T G.709-compatible staircase code with rate R=239/255 is proposed, and field-programmable-gate-array-based simulation results are presented, exhibiting a net coding gain of 9.41 dB at an output error rate of 10 -15 , an improvement of 0.42 dB relative to the best code from the ITU-T G.975.1 recommendation. An error floor analysis technique is presented, and the proposed code is shown to have an error floor at 4.0 × 10 -21. © 2006 IEEE.

Source title: Journal of Lightwave Technology

Series Number: Volume 30 Issue 1

DOI: 10.1109/JLT.2011.2175479

Link: Staircase codes: FEC for 100 Gb/s OTN

Smith, B.P.; Farhood, A.; Hunt, A.; Kschischang, F.R.; Lodge, J.
Perceived picture quality of frame-compatible 3DTV video formats

Year: 2012

Abstract: In the stereoscopic high-definition (HD) frame-compatible formats, the separate left and right views are reduced in resolution and packed to fit within the same video frame as a conventional two-dimensional high-definition signal. Since they do not require additional transmission bandwidth and entail limited changes to the existing broadcasting infrastructure, these formats have been suggested for 3DTV. However, the convenience of frame-compatible formats comes at the expense of lower picture quality of the 3D signal. In this study, we evaluated the loss in picture quality of two frame-compatible formats: 1080i Side-by-Side and 720p Top/Bottom, using a subjective assessment experiment. © 2012 IEEE.

Source title: Proceedings - IEEE International Conference on Multimedia and Expo

DOI: 10.1109/ICME.2012.42

Link: Perceived picture quality of frame-compatible 3DTV video formats

Speranza, F.; Renaud, R.; Vincent, A.; Tam, W.J.
System-on-package MHMIC milimeter-wave frequency synthesizer for 60GHz WPANs

Year: 2012

Abstract: We present a low-cost millimeter-wave frequency synthesizer with ultralow phase noise, implemented using system-on-package (SoP) techniques for high-data-rate wireless personal area network (WPAN) systems operating in the unlicensed 60GHz ISM band (5764GHz). The phase noise specification of the proposed frequency synthesizer is derived for a worst case scenario of an 802.11.3c system, which uses a 64-QAM 512-carrier-OFDM modulation, and a data rate of 5.775Gbps. Our design approach adopts commercial-of-the-shelf (COTS) components integrated in a low-cost alumina-based miniature hybrid microwave integrated circuit (MHMIC) package. The proposed design approach reduces not only the system cost and time-to-market, but also enhances the system performance in comparison with system-on-chip (SoC) designs. The synthesizer has measured phase noise of -111.5dBc/Hz at 1MHz offset and integrated phase noise of 2.8 (simulated: 2.5) measured at 57.6GHz with output power of +1dBm. Copyright © 2012 Boris Spokoinyi et al.

Source title: International Journal of Microwave Science and Technology

DOI: N/A

Link: System-on-package MHMIC milimeter-wave frequency synthesizer for 60GHz WPANs

Spokoinyi, B.; Amaya, R.E.; Haroun, I.; Wight, J.
Air-to-ground mimo channel measurements

Year: 2012

Abstract: Measurements of a MIMO air-to-ground channel at 915 MHz were conducted using multi-element arrays at both the transmitter and receiver. The transmitter was installed in a small semi-autonomous aircraft and the receiver was stationed on the ground in a rural area. Measurements were performedwith the receiver located inside and outside the orbit of the aircraft flight pattern. Characteristics for the MIMO channels measured at both locations are presented. It is observed that the received power can fluctuate more than 10 dB without shadowing of the line-of-sight (LOS) component, impacting diversity and achievable capacity. In some channels, when the power in the LOS component is attenuated, diversity improves due to the increased relative strength of a small number of multipath components.

Source title: Proceedings of the IASTED International Conference on Wireless Communications, WC 2012

DOI: 10.2316/P.2012.784-016

Link: Air-to-ground mimo channel measurements

Squires, C.C.; Colman, G.W.K.; Willink, T.J.
Graph theory for the discovery of non-parametric audio objects

Year: 2012

Abstract: A novel framework based on graph theory for structure discovery is applied to audio to find new types of audio objects which enable the compression of an input signal. It converts the sparse time-frequency representation of an audio signal into a graph by representing each data point as a vertex and the relationship between two vertices as an edge. Each edge is labelled based on a clustering algorithm which preserves a quality guarantee on the clusters. Frequent subgraphs are then extracted from this graph, via a mining algorithm, and recorded as objects. Tests performed using a corpus of audio excerpts show that the framework discovers new types of audio objects which yield an average compression gain of 23.53% while maintaining high audio quality. © 2012 IEEE.

Source title: 2012 11th International Conference on Information Science, Signal Processing and their Applications, ISSPA 2012

DOI: 10.1109/ISSPA.2012.6310498

Link: Graph theory for the discovery of non-parametric audio objects

Srinivasa, C.; Bouchard, M.; Pichevar, R.; Najaf-Zadeh, H.
Integration of auditory masks into a Locally Competitive Algorithm for sparse representations of audio signals

Year: 2012

Abstract: The impact of auditory masking when obtaining sparse representations for audio signals is investigated by integrating a masking model into a Locally Competitive Algorithm. The masking model considers both temporal and frequency domain masking effects. The performance of the new algorithm is verified against the original Locally Competitive Algorithm for different types of sound files. Results show that the new algorithm allows for larger residual error between an input signal and its reconstructed version while maintaining the broadcast quality of the reconstructed version. It does so by shaping the residual error such that this larger error is inaudible. © 2012 IEEE.

Source title: 2012 11th International Conference on Information Science, Signal Processing and their Applications, ISSPA 2012

DOI: 10.1109/ISSPA.2012.6310448

Link: Integration of auditory masks into a Locally Competitive Algorithm for sparse representations of audio signals

Srinivasa, C.; Pichevar, R.; Najaf-Zadeh, H.; Bouchard, M.
A protocol for quantifying the carbon reductions achieved through the provision of low or zero carbon ICT services

Year: 2012

Abstract: In this Conference Paper/Presentation we present a protocol which has been developed for the purposes of providing guidance for estimating the emission reductions that could result from the provision or sourcing of low or zero carbon information and communication technology (ICT) services. This is an increasingly important topic not only because ICT has growing environmental impacts, but also due the technical complexities which underlie the delivery of ICT as a service, especially in respect of the growing use of cloud computing and the provision of ICT services over the internet. The protocol can be used both for creating emission reductions for carbon trading, and the quantification and reporting of related low or zero carbon ICT initiatives within corporate sustainability reports. © 2012 Elsevier Inc. All rights reserved.

Source title: Sustainable Computing: Informatics and Systems

Series Number: Volume 2 Issue 1

DOI: 10.1016/j.suscom.2012.01.001

Link: A protocol for quantifying the carbon reductions achieved through the provision of low or zero carbon ICT services NOTE: A login may be required to access this site.

Steenhof, P.; Weber, C.; Brooks, M.; Spence, J.; Robinson, R.; Simmonds, R.; Kiddle, C.; Aikema, D.; Savoie, M.; Ho, B.; Lemay, M.; Fung, J.; Cheriet, M.
Uneven comb pilots based channel estimation for CDD-OFDM system

Year: 2012

Abstract: Orthogonal Frequency Division Multiplexing (OFDM) is a promising technique for high speed data transmission over multipath fading channels. In an MIMO-OFDM system, cyclic delay diversity (CDD) serves as a simple and elegant solution to exploit transmit diversity. This Conference Paper/Presentation investigates the uneven comb pilots based channel estimation for CDD-OFDM system with periodical frequency selective channel. Our study reveals that uneven comb pilots outperform their even counterpart in complicated channel conditions, such as adaptive CDD, where cyclic delay parameters may change from time to time. Furthermore, we identify the interpolation as a key problem in uneven-pilot based OFDM system and study several scattered data interpolation algorithms. Simulation results show that radial basis function (RBF) interpolation has the best tradeoff in terms of accuracy and computational complexity. © 2012 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2012.6503867

Link: Uneven comb pilots based channel estimation for CDD-OFDM system

Sun, S.; Rong, B.; Hu, R.Q.; Ju, Y.
Progressive distributed video coding with multiple passes for side information update

Year: 2012

Abstract: Distributed video coding is a new video paradigm that transfers the computational bulk from video encoders to decoders. Thus, the scenario of video transmission involving inexpensive encoders and a powerful central decoder would be possible. In a previous work, the authors have proposed a novel distributed video coding scheme with progressive decoding. The proposed architecture considers a chessboard structure for block grouping. A subset of blocks are first sent, decoded and then used to update the side information. Then, the remaining blocks are sent and decoded using the updated and more accurate side information. This progressive technique with two groups of blocks shows an improvement up to 1.7 dB over the conventional DVC architecture. In this Conference Paper/Presentation, we extend the progressive architecture by splitting the frame into three and four groups of blocks rather than only two groups. Further improvement up to 0.4 dB over the progressive architecture with only two groups is obtained. © 2012 IEEE.

Source title: 2012 6th International Conference on Sciences of Electronics, Technologies of Information and Telecommunications, SETIT 2012

DOI: 10.1109/SETIT.2012.6481956

Link: Progressive distributed video coding with multiple passes for side information update

Taieb, M.H.; Chouinard, J.-Y.; Loukhaoukha, K.; Wang, D.; Huchet, G.
Adaptive use of systematic bits in distributed video coding with multiple puncturing matrices

Year: 2012

Abstract: Distributed video coding paradigm aims at transferring the major part of the processing computation effort from the encoder to the decoder. Motion interpolation is done at the decoder to generate side information (SI) through motion compensated temporal interpolation (MCTI). SI is considered as a noisy version of the original data: channel control coding schemes, such as turbo coding, are used to eliminate the errors (SI inaccuracies). The video data is turbo encoded and the parity bits are sent to the decoder. The systematic bits, however, are discarded since the decoder already disposes of SI that can be used for the channel likelihood ratio calculations. However, when the MCTI generation of SI is highly corrupted, the channel likelihood ratios based on the SI are inefficient and even misleading. A number of parity bits number exceeding the original data length may then be required, thus leading to an undesirable expansion effect. In this Conference Paper/Presentation, we propose a method to detect adaptively the situations where the SI is of lower quality. Then puncturing matrices, enabling systematic bits, are used to help computing reliable channel likelihood ratios. An improvement up to 0.5 dB is reported for PSNRs vs bit rate performances. © 2012 IEEE.

Source title: 2012 IEEE Visual Communications and Image Processing, VCIP 2012

DOI: 10.1109/VCIP.2012.6410839

Link: Adaptive use of systematic bits in distributed video coding with multiple puncturing matrices

Taieb, M.H.; Chouinard, J.-Y.; Wang, D.
Progressive coding and side information updating for distributed video coding

Year: 2012

Abstract: Distributed video coding is a research field which brings together error coding techniques along with video compression methods. It is usually based on a Slepian- Wolf encoder which often involves turbo codes because of their strong error correction capabilities. Typically, the turbo encoder generates parity bits which are sent to refine the side information reconstructed at the decoder by interpolation of the already received neighboring key frames. In this Conference Paper/Presentation we introduce a novel distributed video coding scheme with progressive decoding. The side information is updated progressively as long as the current frame is being decoded. The proposed architecture considers a chess-board structure for block grouping. A subset of blocks are first sent, decoded and then used to update the side information. Then, the remaining blocks are sent and decoded using the updated and more accurate side information. The implementation of the progressive coding shows an improvement up to 1.7 dB over the conventional DVC architecture. © 2012 ISSN 2073-4212.

Source title: Journal of Information Hiding and Multimedia Signal Processing

Series Number: Volume 3 Issue 1

DOI: N/A

Link: Progressive coding and side information updating for distributed video coding (PDF document)

Taieb, M.H.; Chouinard, J.-Y.; Wang, D.; Loukhaoukha, K.; Huchet, G.
Extending 60 GHz UWB coverage to medium distances under NLOS conditions

Year: 2012

Abstract: Ultra-wideband (UWB) communications can be achieved under non-line-of-sight (NLOS) propagation conditions at distances over 100 m using a single carefully designed and located microwave reflector in conjunction with a multi-carrier modulation technique such as orthogonal frequency-division multiplexing (OFDM) that is less sensitive to multipath effects than single-carrier modulation. One key factor in achieving high data throughputs is the average intensity levels of the reflected signals that are produced by using high-gain antennas and reflectors. A second key factor is the proper design of a reflector to minimize delays spreads and provide adequate signal strengths. A third key factor is the application of a suitable technique to recover defective OFDM subcarriers. In order to firmly ground performance predictions on experimental measurements, precise frequency response measurements of reflected signals were carried out in a 1 GHz band centered around 60.1 GHz. Measurements of the frequency response of NLOS indoor propagation channels were performed for three different laterally-positioned receive antenna locations and used for single-input multiple-output (SIMO) studies. Based on these measurements, OFDM data transmission streams were simulated. It was determined that individual subchannels of the OFDM data transmission stream suffered from various levels of distortion resulting in the lack of availability of some OFDM subchannels for UWB data transmission. Using the technique of post-discrete Fourier transform (post-DFT) multiple subcarrier selection (MSCS), it was found that data throughputs comparable to those achievable under quasi-perfect propagation conditions could be obtained in NLOS indoor channels provided that the delay spread was short (18.1 ns). The signal-amplitude metric was used for the selection of OFDM subcarriers. © 2012 IEEE.

Source title: 2012 International Conference on Wireless Communications in Underground and Confined Areas, ICWCUCA 2012

DOI: 10.1109/ICWCUCA.2012.6402502

Link: Extending 60 GHz UWB coverage to medium distances under NLOS conditions

Talbi, L.; Lebel, J.
Problem-driven three-dimensional television research involving human visual perception studies

Year: 2012

Abstract: Stereoscopic three-dimensional (S3-D) visual entertainment has become a hot technology that is emerging very quickly in many new electronic devices and visual communication systems. Although this rapid growth of S3-D technology is relatively recent, visual scientists have been conducting research on fundamental issues of stereoscopic 3-D television (3-D TV) development and deployment for many years. To illustrate how human visual perception research has been applied to the study of stereoscopic 3-D TV related issues, selected experimental studies that were conducted by the Communications Research Centre Canada within the last 15years are presented. The studies reflect empirical investigations on a wide range of topics from an applied vision research perspective: the prevalence of stereo-deficiency, the potential use of mixed-resolution binocular imaging for reducing transmission bandwidth, the role of stereoscopic object motion on visual comfort, and the use of surrogate depth maps for the conversion of standard video to S3-D format to increase the availability of S3-D program contents. © Japanese Psychological Association 2012.

Source title: Japanese Psychological Research

Series Number: Volume 54 Issue 1

DOI: 10.1111/j.1468-5884.2011.00507.x

Link: Problem-driven three-dimensional television research involving human visual perception studies

Tam, W.J.; Speranza, F.; Vazquez, C.
Visual comfort: Stereoscopic objects moving in the horizontal and mid-sagittal planes

Year: 2012

Abstract: Two experiments were conducted to examine the visual comfort of stereoscopic images. The test video sequences consisted of moving meteorite-like objects against a blue sky background. In the first experiment, a panel of viewers rated stereoscopic sequences in which the objects moved back and forth in depth. The velocity of movement, disparity (depth) range, and disparity type (i.e., depth position with respect to the screen plane: front, behind, or front/behind) of the objects varied across sequences. In the second experiment, the same viewers rated stereoscopic test sequences in which the target objects moved horizontally across the screen. Also in this case, the velocity, disparity magnitude, and disparity type of the objects varied across sequences. For motion in the depth direction, the results indicate that visual comfort is significantly influenced by the velocity, disparity range, and disparity type of the moving objects. We also found significant interactions between velocity and disparity type and between disparity type and disparity range. For motion across the screen in the horizontal plane, ratings of visual comfort depended on velocity and disparity magnitude. The results also indicate a significant interaction between velocity and disparity. In general, the overall results confirm that changes in disparity of stereoscopic images over time are a significant contributor to visual discomfort. Interestingly, the detrimental effect of object velocity on visual comfort are manifested even when the changes are confined within the generally accepted visual comfort zone of less than 60 arc minutes of horizontal disparity. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Source title: Proceedings of SPIE - The International Society for Optical Engineering

Series Number: Volume 8288

DOI: 10.1117/12.909121

Link: Visual comfort: Stereoscopic objects moving in the horizontal and mid-sagittal planes

Tam, W.J.; Speranza, F.; Vazquez, C.; Renaud, R.; Hur, N.
Role of hydrogen loading and glass composition on the defects generated by the femtosecond laser writing process of fiber Bragg gratings

Year: 2012

Abstract: The creation of fiber Bragg gratings (FBGs) in optical fibers by laser irradiation causes the formation of defects in the modified glass. We have used confocal fluorescence spectroscopy to identify the location and types of defects formed after writing FBGs with the femtosecond laser phase mask technique. Our results show that non-bridging oxygen hole centers (NBOHCs) and self-trapped excitons (Ed') are formed throughout all-silica core Sumitomo Z-fiber. Similar defects are observed for Ge-doped silica fiber, Corning SMF-28, but in this case the relative concentrations of NBOHC and Ed' vary from the core to the cladding. In both fibers, hydrogen loading prior to irradiation appears to passivate the defects except in the Ge-doped core where the NBOHC defects persist. © 2012 Optical Society of America.

Source title: Optical Materials Express

Series Number: Volume 2 Issue 11

DOI: 10.1364/OME.2.001663

Link: Role of hydrogen loading and glass composition on the defects generated by the femtosecond laser writing process of fiber Bragg gratings

Troy, N.; Smelser, C.W.; Krol, D.M.
Relationship between the maximum likelihood emitter location estimators based on received signal strength (RSS) and received signal strength difference (RSSD)

Year: 2012

Abstract: Under the assumption of a log-normal path loss model, maximum likelihood (ML) emitter location estimators are derived for both received signal strength (RSS) and received signal strength difference (RSSD) information. It is then shown that these ML estimators are identical, contrary to the seemingly common perception that the RSS-based ML location estimator should outperform the RSSD-based ML location estimator. The Cramer-Rao lower bounds (CRLB) for the average miss distance are also shown to be identical. Using the least squares estimation criterion, a non-linear least squares (NLS) emitter location estimator is also formulated in this Conference Paper/Presentation for comparison. These theoretical developments are illustrated by computer simulation experiments. © 2012 IEEE.

Source title: 2012 26th Biennial Symposium on Communications, QBSC 2012

DOI: 10.1109/QBSC.2012.6221353

Link: Relationship between the maximum likelihood emitter location estimators based on received signal strength (RSS) and received signal strength difference (RSSD)

Wang, S.; Inkol, R.; Jackson, B.R.
Hybrid RSS/AOA emitter location estimation based on least squares and maximum likelihood criteria

Year: 2012

Abstract: Linear least squares (LS) and maximum likelihood (ML) estimators are derived for emitter geolocation using both received signal strength (RSS) and angle of arrival (AOA) information obtained from an heterogeneous sensor array. The results of simulation experiments provide useful insights into the behavior of these hybrid approaches and demonstrate that the use of simple RSS sensors to augment traditional AOA sensors can significantly improve the attainable geolocation accuracy. © 2012 IEEE.

Source title: 2012 26th Biennial Symposium on Communications, QBSC 2012

DOI: 10.1109/QBSC.2012.6221344

Link: Hybrid RSS/AOA emitter location estimation based on least squares and maximum likelihood criteria

Wang, S.; Jackson, B.R.; Inkol, R.
A new upper bound for the normalized detection threshold of the FFT-based summation detector

Year: 2012

Abstract: The FFT summation detector, a detection scheme extensively used in applications such as civilian spectrum monitoring and military radio surveillance, is also applicable to cognitive radio spectrum sensing applications. The practical implementation of the FFT summation detector depends on the reliable numerical computation of the normalized detection threshold, Tn. Although this problem has been the subject of considerable study, the computation of Tn still presents difficulties. Existing approaches depend on numerical procedures such as the Newton-Raphson and the golden section search algorithms, which often fail to converge when the number of input data blocks, L, or the number of FFT bins, N, used for channel power estimation is large. To circumvent such numerical difficulties, easily computable lower and upper bounds for Tn are of great interest as they are essential for verifying the accuracy of approximations to Tn when the true value of Tn is not available. Although several lower bounds for Tn have been proposed, few good upper bounds for Tn have been derived. This paper proposes a new upper bound for Tn, which is easily computed for larger values of the probability of false alarm, Pfa, using the Imhof integral formula.

Source title: IEEE VehicularTechnology Conference (VTC Fall 2012)

DOI: 10.1109/VTCFall.2012.6399038

Link: A new upper bound for the normalized detection threshold of the FFT-based summation detector

Wang, S.; Patenaude, F.; Inkol, R.
Hiding depth information into H.264 compressed video using reversible watermarking

Year: 2012

Abstract: A scheme is proposed to hide 3D information (depth map) into H.264 compressed video using reversible watermarking. The watermark embedder works jointly with the H.264 encoder with concern of bit rate control and low complexity. The depth information is hidden in the quantized DCT domain of the compressed video in our proposed method. The bit-shift operation is used for watermarking to shift the energy distribution of the quantized DCT coefficients for the purpose of bit rate control and low calculation complexity. Further more, the decoder at the receiver side can restore the original video without quality loss after the watermark is extracted. The experimental results show that the watermarking capacity is large enough for hiding the related depth information of the cover video sequence. Besides, the watermarked video size is smaller than the sum of original video sequence plus the hidden depth information, which means that our watermarking method can secure the depth information while save the transmission bandwidth for depth information. © 2012 ACM.

Source title: CBMAS-EH 2012 - Proceedings of the 2012 ACM Workshop on Cloud-Based Multimedia Applications and Services for E-Health, Co-located with ACM Multimedia 2012

DOI: 10.1145/2390906.2390915

Link: Hiding depth information into H.264 compressed video using reversible watermarking

Wang, W.; Zhao, J.; Tam, W.J.; Speranza, F.
Spectral occupancy of fixed and mobile allocations within the High Frequency band

Year: 2012

Abstract: Power levels in the High Frequency (HF) band from 3 to 30 MHz were measured to determine channel occupancy statistics including patterns in time and frequency. Congestion in Canadian spectrum allocations for fixed and mobile users and patterns in the ambient radio noise power across the HF band were examined. A receiver site was set up in Ottawa, Canada using a spectrum analyzer and an omni-directional, horizontally polarized antenna having an elevation pattern optimized for reception of signals arriving via sky wave propagation. Diurnal and random fluctuations in channel occupancy, congestion, and noise measurements were observed and sample data plots for fixed and mobile allocations were presented and discussed. The availability of unoccupied channels in bandwidth increments of 3, 12, and 24 kHz for each 1 MHz frequency range is discussed and may be used to inform future assignments for fixed and land mobile services in the Canadian Table of Frequency Allocations. Hourly variations in channel occupancy show that there are ample spans of contiguous unoccupied spectrum to support channel bandwidths up to 24 kHz during most hours of the day; however, during the most congested times, even 3 kHz contiguous channels are not available in the frequency ranges that are optimal for propagation. These results suggest that spectrum availability in the region can support the use of wideband HF modems; however, the optimal modulation bandwidth will vary according to the time of day and the number of channels required.

Source title: IET Conference Publications

Series Number: Volume 2012 Issue 594CP

DOI: 10.1049/cp.2012.0364

Link: Spectral occupancy of fixed and mobile allocations within the High Frequency band

Warner, D.I.; Bantseev, S.; Serinken, N.
Efficient rank-adaptive least-square estimation and multiple-parameter linear regression using novel dyadically recursive hermitian matrix inversion

Year: 2012

Abstract: Least-square estimation (LSE) and multiple-parameter linear regression (MLR) are the important estimation techniques for engineering and science, especially in the mobile communications and signal processing applications. The majority of computational complexity incurred in LSE and MLR arises from a Hermitian matrix inversion. In practice, the Yule-Walker equations are not valid, and hence the Levinson-Durbin algorithm cannot be employed for general LSE and MLR problems. Therefore, the most efficient Hermitian matrix inversion method is based on the Cholesky factorization. In this Conference Paper/Presentation, we derive a new dyadic recursion algorithm for sequential rank-adaptive Hermitian matrix inversions. In addition, we provide the theoretical computational complexity analyses to compare our new dyadic recursion scheme and the conventional Cholesky factorization. We can design a variable model-order LSE (MLR) using this proposed dyadic recursion approach thereupon. Through our complexity analyses and the Monte Carlo simulations, we show that our new dyadic recursion algorithm is more efficient than the conventional Cholesky factorization for the sequential rank-adaptive LSE (MLR) and the associated variable model-order LSE (MLR) can seek the trade-off between the targeted estimation performance and the required computational complexity. Our proposed new scheme can benefit future portable and mobile signal processing or communications devices. © 2012 Hsiao-Chun Wu et al.

Source title: International Journal of Antennas and Propagation

Series Number: Volume 2012

DOI: 10.1155/2012/891932

Link: Efficient rank-adaptive least-square estimation and multiple-parameter linear regression using novel dyadically recursive hermitian matrix inversion

Wu, H.-C.; Chang, S.Y.; Le-Ngoc, T.; Wu, Y.
Flow availability in two-layer networks with dedicated path protection

Year: 2012

Abstract: Traffic flows with protection can be disrupted in network failures that are beyond the protection capability. We analyze availability of upper-layer flows in two-layer networks with dedicated path protection at upper or lower layer.

Source title: Asia Communications and Photonics Conference, ACP 2012

DOI: 10.1364/ACPC.2012.ATh4D.2

Link: Flow availability in two-layer networks with dedicated path protection

Wu, J.; Ni, W.; Huang, C.
Peer-to-Peer Network Architecture

Year: 2012

Abstract: [No abstract available]

Source title: Handbook of Computer Networks

Series Number: Volume 3

DOI: 10.1002/9781118256107.ch9

Link: Peer-to-Peer Network Architecture

Wu, J.; Savoie, M.
Forward-looking WDM network reconfiguration with per-link congestion control

Year: 2012

Abstract: We study reconfigurations of wavelength-routed Wavelength Division Multiplexing (WDM) networks in response to lightpath demand changes, with the objective of servicing more lightpath demands without additional network resources from a long-term network operation point of view. For the reconfiguration problem under study, we assume WDM network operators are provided with lightpath demands in batches. With limited network resources, our problem has two unique challenges: balancing network resource allocations between current and future lightpath demands, and modeling future lightpath demands. The first challenge implies making tradeoffs between accepting as many current immediate lightpath demands as possible and reserving a certain amount of network resources for near future predicted lightpath demands. The second challenge implies modeling future predicted lightpath demands, which are not exactly known or certain as the current lightpath demands. Our proposed model allows a natural separation between the operation of the optical layer and the user traffic layer (predominantly the IP-layer), while supporting their interactions, for which we propose a new formulation for per-link congestion control, associated with a mathematical solution procedure. Our simulation results reveal that by properly controlling resource allocations in the current session using our proposed mechanism, rejections in future sessions are greatly reduced. © 2011 Her Majesty the Queen in Rights of Canada.

Source title: Journal of Network and Systems Management

Series Number: Volume 20 Issue 11

DOI: 10.1007/s10922-011-9212-2

Link: Forward-looking WDM network reconfiguration with per-link congestion control

Wu, J.; Zhang, J.; Von Bochmann, G.; Savoie, M.
Cloud transmission: A new spectrum-reuse friendly digital terrestrial broadcasting transmission system

Year: 2012

Abstract: This Conference Paper/Presentation introduces a new transmission system "Cloud Transmission (Cloud Txn)" for terrestrial broadcasting or point-to-multipoint multimedia services. The system is based on the concept of increasing the reception robustness, and using the spectrum more efficiently. As such, the system is designed to be robust to co-channel interference, immune to multipath distortion, and is highly spectrum reuse friendly. It can increase the spectrum utilization significantly (3 to 4 times) by making all terrestrial RF channels in a city/market available for broadcast service. The system has the robustness required for providing mobile, pedestrian and indoor reception. It can be used for both small and large cell applications. The receiver is simple and energy efficient. The proposed system is scalable and can be implemented progressively, i.e., providing an easy transition from the traditional systems to the new Cloud Txn system. It can also coexist with the existing DTV systems and their newer versions, such as DVB-T2 or Super Hi-Vision systems. © 2012 IEEE.

Source title: IEEE Transactions on Broadcasting

Series Number: Volume 58 Issue 3

DOI: 10.1109/TBC.2012.2199598

Link: Cloud transmission: A new spectrum-reuse friendly digital terrestrial broadcasting transmission system

Wu, Y.; Rong, B.; Salehian, K.; Gagnon, G.
A new positioning system using DVB-T2 transmitter signature waveforms in single frequency networks

Year: 2012

Abstract: A new positioning system using transmitter signature waveforms of DVB-T2 in Single Frequency Networks (SFNs) is proposed in this Conference Paper/Presentation. Due to the wide coverage of the SFN and extremely high transmission power of digital television (DTV) transmitting stations, positioning based on DTV SFN can be considered as a promising complementary to remedy the poor coverage of the Global Positioning System (GPS) in dense multipath propagation environments. Based on the newly proposed transmitter signature waveform in DVB-T2 systems, transmitter identification and timing estimation using threshold-based first path detection method are jointly achieved, and subsequently utilized for Time-Difference-of- Arrival (TDOA)-based positioning approach. The proposed positioning system is fully compatible with the current DVB-T2 standard and therefore, no dedicated hardware modification is required. The performance of the proposed positioning system is evaluated through computer simulations under different signal propagation scenarios and compared with existing methods. Simulation results show that very high accuracy can be obtained with the proposed positioning system. © 2012 IEEE.

Source title: IEEE Transactions on Broadcasting

Series Number: Volume 58 Issue 3

DOI: 10.1109/TBC.2012.2191693

Link: A new positioning system using DVB-T2 transmitter signature waveforms in single frequency networks

Yang, J.; Wang, X.; Rahman, M.J.; Park, S.I.; Kim, H.M.; Wu, Y.
Novel fast algorithm to design optimal eigen filters for transmission systems

Year: 2012

Abstract: The optimal finite impulse response (FIR) filter design has been very popular in science and engineering over many decades due to its guaranteed stability and wide variety of applications, especially for transmission systems. Designing eigen-filters is a common signal processing paradigm. Given a fixed filter length, the objective function is formulated in terms of passband and stop-band energies, and then the appropriate optimization technique is employed to determine the impulse response. In this Conference Paper/Presentation, we would like to present a novel computationally-efficient optimal eigen-filter design scheme. Since the signal processing storage devices become less and less costly and more and more powerful, designing long FIR filters dynamically to address different channel conditions and modulations becomes crucial in modern telecommunication and signal processing applications. Computationally-efficient filter design schemes, which can be facilitated in real-time, are in high demand. Our proposed technology is based on fast eigen-decomposition. The computational complexity of our proposed new method is O(M2) compared to O(M3) of the conventional technique. © 2012 IEEE.

Source title: IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, BMSB

DOI: 10.1109/BMSB.2012.6264311

Link: Novel fast algorithm to design optimal eigen filters for transmission systems

Zhang, H.; Wu, H.-C.; Wu, Y.; Rong, B.
Disparity-compensated reconstruction of frame-compatible 3D videos

Year: 2012

Abstract: This Conference Paper/Presentation presents an algorithm for the reconstruction of frame-compatible 3D videos. Disparity-compensation based framework is investigated for the up-conversion of complementarily, horizontally or vertically decimated frame-compatible formats to their original 2D full resolution. Two issues, namely spatial resolution of disparity maps and intensity/color differences of stereo image, that affect image quality of full-resolution images reconstructed using the disparity compensation technique are studied. To deal with the intensity/color imbalance between stereo images, a new algorithm is proposed for the reconstruction. Experimetal results with four sequences confirmed the outcomes of the studies. © 2012 IEEE.

Source title: IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, BMSB

DOI: 10.1109/BMSB.2012.6264267

Link: Disparity-compensated reconstruction of frame-compatible 3D videos

Zhang, L.; Li, W.; Wang, D.; Zheng, D.
Segmentation of source symbols for adaptive arithmetic coding

Year: 2012

Abstract: Adaptive arithmetic coding is a general technique for coding source symbols of a stochastic process based on an adaptive model. The adaptive model provides measures of the statistics of source symbols and is updated, along with encoding/decoding processes, when more encoded/decoded symbols are fed as samples to the adaptive model. The coding performance depends on how well the adaptive model fits the statistics of source symbols. If the number of source symbols is large and the number of samples is small, the adaptive model may not be able to provide valid measures of the statistics, which results in an inefficient coding performance of the adaptive arithmetic coder. To this end, this Conference Paper/Presentation presents segmentation of source symbols to improve the performance of the adaptive arithmetic coder. Each source symbol is divided into several segments. Each segment is separately coded with an adaptive arithmetic coder. With this division, possible values of each segment are concentrated within a small range. Given the limited number of samples, this concentration leads to a better fit of the adaptive model to the statistics of source symbols and therefore to an improvement of the coding efficiency. The proposed coding algorithm is applied to lossless motion vector coding for video transmission as an application example to show its performance improvement and coding gains. © 2012 IEEE.

Source title: IEEE Transactions on Broadcasting

Series Number: Volume 58 Issue 2

DOI: 10.1109/TBC.2012.2186728

Link: Segmentation of source symbols for adaptive arithmetic coding

Zhang, L.; Wang, D.; Zheng, D.
DIBR-based conversion from monoscopic to stereoscopic and multi-view video

Year: 2012

Abstract: This chapter aims to provide a tutorial on 2D-to-3D video conversion methods that exploit depth-image-based rendering (DIBR) techniques. It is devoted not only to university students who are new to this area of research, but also to researchers and engineers who want to enhance their knowledge of video conversion techniques. The basic principles and the various methods for converting 2D video to stereoscopic 3D, including depth extraction strategies and DIBR-based view synthesis approaches, are reviewed. Conversion artifacts and evaluation of conversion quality are discussed, and the advantages and disadvantages of the different methods are elaborated. Furthermore, practical implementations for the conversion from monoscopic to stereoscopic and multi-view video are drawn.

Source title: 3D-TV System with Depth-Image-Based Rendering (Book)

DOI: 10.1007/978-1-4419-9964-1_4

Link: DIBR-based conversion from monoscopic to stereoscopic and multi-view video

Zhang, L.; Vazquez, C.; Huchet, G.; Tam, W.J.
Quantization scheme for high definition video coding based on node-cell pixel structure

Year: 2012

Abstract: An intra-only video coding algorithm based on a so called node-cell pixel coding structure has been proposed for high definition video by the authors. This novel coding structure divides pixels within one macro-block into node and cell pixels. The node pixels are first encoded using DCT, quantization, and entropy coding. The cell pixels are then interpolated using the reconstructed node pixels, and the corresponding residuals are encoded also using DCT, quantization, and entropy coding. Following this coding scheme, this Conference Paper/Presentation further investigates the relationship of quantization parameters between node and cell pixels. To establish a model of this relationship, an extensive set of experiments were designed to perform both node and cell pixel encoding with different video sequences under different bit rates. The coding performance in terms of both bit-rate and distortion was measured for different combinations of the two quantization parameters. The optimal combinations, which bring the best coding performance, were identified and used to establish the mode. The experimental results show that the quantization parameter of cell pixels should be larger than the quantization parameter of node pixels to achieve a high coding performance. A new quantization scheme is designed based on this QP model and a gain up to 0.5 dB over the previous work is achieved. © 2012 IEEE.

Source title: IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, BMSB

DOI: 10.1109/BMSB.2012.6264266

Link: Quantization scheme for high definition video coding based on node-cell pixel structure

Zheng, D.; Zhang, L.; Wang, D.
Multilateration localization in the presence of anchor location uncertainties

Year: 2012

Abstract: Multilateration is a fundamental localization technique for wireless sensor network applications. Classical multilateration techniques typically assume that the anchor locations are known and error free, an assumption that is always not valid in practice. Although the popular total least squares (TLS) method is able to take into account such errors in general, it requires that the noise components in the formulated data matrices be identically, independently distributed. In multilateration localization, however, it can be shown that the noise components in the formulated equations are algebraically related. In this Conference Paper/Presentation, we formulate multilateration for sensor localization based on the use of the constrained total least squares (CTLS) method. By assuming that distance measurement errors are relatively small and can be neglected, we show that the CTLS solution leads to a weighted least squares problem. Computer simulations are used to demonstrate the effectiveness and performance of the proposed technique. © 2012 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2012.6503131

Link: Multilateration localization in the presence of anchor location uncertainties

Zhou, Y.; Li, J.; Lamont, L.
Modeling of packet dropout for UAV wireless communications

Year: 2012

Abstract: In this Conference Paper/Presentation, we investigate the problem of channel modeling of packet dropout for unmanned aerial vehicle (UAV) communications. A two-state Markov model is proposed, which incorporates the effects of Ricean fading. The proposed model is able to capture the non-stationary packet dropout characteristics of the channels. A closed-form solution is provided for estimating the model parameters from packet traces. Computer simulations and analysis are carried out to demonstrate the performance and effectiveness of the proposed model. © 2012 IEEE.

Source title: 2012 International Conference on Computing, Networking and Communications, ICNC'12

DOI: 10.1109/ICCNC.2012.6167508

Link: Modeling of packet dropout for UAV wireless communications

Zhou, Y.; Li, J.; Lamont, L.; Rabbath, C.-A.
A markov-based packet dropout model for UAV wireless communications

Year: 2012

Abstract: In this Conference Paper/Presentation, we study the problem of modeling packet dropout for unmanned aerial vehicle (UAV) wireless communications. A Markov model is proposed, which incorporates the effects of Ricean fading. Unlike the classic Markov channel models, the proposed model is a two-state hidden Markov model with each state being associated with a time-varying packet error rate. The model is able to capture the non-stationary packet dropout characteristics of wireless channels. Intuitively, we use the time-varying packet error rate associated with the channels to describe the non-stationary nature of the packet dropouts, and the two-state Markov model to capture the correlation of the packet dropouts. A closed-form solution is provided for estimating the model parameters from network packet traces. Computer simulations and analysis are carried out to demonstrate the performance and effectiveness of the proposed model. © 2012 ACADEMY PUBLISHER.

Source title: Journal of Communications

Series Number: Volume 7 Special Issue 6

DOI: 10.4304/jcm.7.6.418-426

Link: A markov-based packet dropout model for UAV wireless communications

Zhou, Y.; Li, J.; Lamont, L.; Rabbath, C.-A.
Analytical performance of M-PSK communications systems in the presence of gain/phase imbalances and DC-offsets

Year: 2012

Abstract: This letter addresses the performance of M-PSK communications systems in the presence of gain/phase imbalances and DC-offsets in in-phase and quadrature channels. A model is established to represent the gain/phase imbalances and DC-offsets in both the transmitter and the receiver, and two closed-form formulas are derived to calculate the symbol error rate (SER) of the M-PSK communications systems in the presence of these impairments. Computer simulations are conducted to validate the derivation, and the results show that the SER calculated from the formulas closely matches the simulation results. The formulas provide an accurate guideline for communications system architects/engineers to evaluate the impacts of various imbalances and offsets on the system performance and to determine the required component specifications. © 2012 IEEE.

Source title: IEEE Wireless Communications Letters

Series Number: Volume 1 Issue 4

DOI: 10.1109/WCL.2012.061212.120348

Link: Analytical performance of M-PSK communications systems in the presence of gain/phase imbalances and DC-offsets

Zhu, Z.; Huang, X.; Caron, M.
Channel equalization and timing recovery technique for chaotic communications systems

Year: 2012

Abstract: In this Conference Paper/Presentation, a minimum nonlinear prediction error (MNPE) based channel equalization and timing recovery technique is proposed for chaotic communications systems. This blind technique utilizes the short-term predictability of a chaotic signal to estimate the equalizer coefficients and the timing delay without any training signals. Both computer simulation and experimental setup are carried out to validate the proposed technique. Compared with the constant modulus algorithm (CMA) and higher-order statistics (HOS) based inverse filter techniques, which are commonly used in the conventional communications systems, the proposed MNPE technique can achieve better demodulation performance. © 2012 IEEE.

Source title: ISCAS 2012 - 2012 IEEE International Symposium on Circuits and Systems

DOI: 10.1109/ISCAS.2012.6272109

Link: Channel equalization and timing recovery technique for chaotic communications systems

Zhu, Z.; Leung, H.
Experimental Results of a Quadrature Modulator Self-Calibration

Year: 2012

Abstract: This Conference Paper/Presentation presents an L-band experimental setup to investigate the LO and image suppression capability of an self-calibration technique proposed by CRC.

Source title: 30th AIAA International Communications Satellite System Conference (ICSSC) (2012)

DOI: 10.2514/6.2012-15104 

Link: Experimental Results of a Quadrature Modulator Self-Calibration

Zhu, Zhiwen; Huang, Xinping; Caron, Mario
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