Scientific publications—2013

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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—2013
Title Authors
A key management scheme for tiered wireless sensor network with self-healing capability

Year: 2013

Abstract: This paper presents a novel key management scheme for a tiered self-healing wireless sensor network. A tiered wireless sensor network with self-healing features draws extensive attention because of its scalability, robustness and reliability. A tiered key management scheme to support the cluster membership and the self-healing features is proposed with emphasis on the control of a node's participation and re-keying when joining a new cluster. The security and overhead analysis demonstrates the proposed scheme is effective and efficient with respect to communication, computation, and memory overhead for operation in a hostile environment.

Source title: Ground/Air Multisensor Interoperability, Integration, and Networking for Persistent ISR IV

Series Number: Volume 8742

DOI: 10.1117/12.2014616

Link: A key management scheme for tiered wireless sensor network with self-healing capability

Maoyu Wang, Helen Tang, F. Richard Yu
Detailed Study of Millimeter Wave EBG Guide: Broadbanding Techniques, Modal Structures and Crosstalk Behavior

Year: 2013

Abstract: An electromagnetic band gap (EBG) waveguide using holes drilled in a dielectric substrate is investigated in this paper. A broadbanding technique is suggested and implemented through a detailed study of the modal behaviour of the guiding structure. The stop band of the EBG waveguide was adjusted by changing the width of the waveguide to increase its bandwidth. It is shown that the propagating mode is a quasi-TEM by examining the dispersion properties of the propagating mode. An EBG waveguide of 49.1mm (equivalent to 19 EBG cells) was designed and fabricated. The simulation results show better than -10 dB return loss performance from 27 GHz to 31.5 GHz with insertion loss of better than 2.5 dB over the same bandwidth, and also high isolation in the range of -20 dB with an adjacent similar EBG waveguide. There is a good agreement between the measured data and simulation results. A microstrip line was also fabricated and used as a benchmark for comparison with the designed EBG waveguide. The group velocity of this waveguide is nearly constant across its operating frequency band which implies low frequency dispersion and is also a confirmation of the quasi-TEM nature of the EBG fundamental mode. Also, using the physical insight gained from a careful study of the EBG guide, a simple method is suggested for the calculation of the dispersion characteristic of its fundamental mode.

Source title: Progress in Electromagnetics Research B

Series Number: Volume 50

DOI: 10.2528/PIERB13022010

Link: Detailed Study of Millimeter Wave EBG Guide: Broadbanding Techniques, Modal Structures and Crosstalk Behavior

Abdo, Y.S.E; Chaharmir, M.R.; Shaker, J.; Antar, Y.M.M.
A new type of transmission line-based metamaterial resonator and its implementation in original applications

Year: 2013

Abstract: In this paper, a new type of transmission line-based metamaterial resonator is proposed. The structure is based on a modified uniplanar series resonator bent to form a close square loop inclusion which contains a distributed capacitance and inductance. Many advantages of the proposed structure over conventional split ring resonators are discussed. Based on simple transmission line theory, the resonance frequency at which a deep rejection frequency band occurs with sharp cutoff rates beside the stopband, due to the presence of negative effective permeability in the dielectric slab of the host transmission line in the vicinity of resonance, is calculated and verified with simulated and measured results. Two prototype microwave devices are designed to illustrate the potentiality of the proposed inclusion. The first design represents a dual-band bandstop filter with designed center band frequencies at 1.6 and 2.2 GHz. The lumped element model of this filter contains four series-connected parallel LC resonators which are implemented using our high Q-factor artificial magnetic materials (AMMs) patterned on the backside of a coplanar waveguide (CPW) transmission line. The second device is a miniaturized hybrid branch line coupler operating at 2.4 GHz, based on a special loading technique that increases the electric length of transmission lines by patterning the ground plane under the conductor trace in microstrip lines with the complementary, dual-behavior, configuration of AMMs. A size reduction factor up to 16.95% is achieved compared to conventional couplers. For both design examples the measured and simulated responses are in very good agreement which validates our work. © 1965-2012 IEEE.

Source title: IEEE Transactions on Magnetics

Series Number: Volume 49 Issue 3

DOI: 10.1109/TMAG.2012.2230248

Link: A new type of transmission line-based metamaterial resonator and its implementation in original applications

Abu Safia, O.; Talbi, L.; Hettak, K.
CPW discontinuities-based metamaterial inclusions

Year: 2013

Abstract: In this paper, a new resonance-type metamaterial inclusion based on coplanar waveguide (CPW) discontinuities is proposed. The inclusion consists of series-connected distributed capacitance and inductance on the center strip of a closed-loop modified CPW transmission line. The resonant frequency at which the magnetic coupling between the inclusion and the host transmission line occurs is calculated, and compared to simulated and measured results. In addition, a modified version of the proposed metamaterial inclusion based on increasing the capacitance inside the inclusion to shift the resonance frequency to the left in order to provide extra compactness is designed and fabricated. The paper discusses the advantages of using the proposed inclusions over conventional split ring resonators. Measured and simulated results for both inclusions agree well with the theoretical models which are developed to find the resonant frequencies. The proposed inclusions are suitable for resonance-based microwave components such as filters. © 2013 IEEE.

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

DOI: 10.1109/APS.2013.6711248

Link: CPW discontinuities-based metamaterial inclusions

Abu Safia, O.; Talbi, L.; Hettak, K.; Kabiri, A.
Beam squint suppression in offset-fed reflectarrays

Year: 2013

Abstract: A novel approach is proposed to suppress the frequency-dependent beam squint of offset-fed reflectarray patterns. The design comprises two offset feeds located at opposite ends of the reflectarray, in the plane of offset, simultaneously illuminating the reflectarray. This generates a single beam that does not squint from the desired design direction at off-center frequencies. The concept is validated by comparing the full-wave simulated patterns to measured counterparts. © 2002-2011 IEEE.

Source title: IEEE Antennas and Wireless Propagation Letters

Series Number: Volume 12

DOI: 10.1109/LAWP.2013.2260124

Link: Beam squint suppression in offset-fed reflectarrays

Almajali, E.; McNamara, D.A.; Shaker, J.; Chaharmir, M.R.
Grating lobe control in dual-feed single-beam reflectarrays and power combiners

Year: 2013

Abstract: The reason for the presence of unwanted sidelobes in multifeed single-beam reflectarrays and power combiners is shown to be a grating lobe phenomenon due to 'amplitude clustering' of the scattered field over the reflectarray aperture. A means of controlling the level of these lobes is proposed and validated using full-wave analysis and measurements. © 2013 IEEE.

Source title: IEEE Antennas and Wireless Propagation Letters

Series Number: Volume 12

DOI: 10.1109/LAWP.2013.2283572

Link: Grating lobe control in dual-feed single-beam reflectarrays and power combiners

Almajali, E.; McNamara, D.A.; Shaker, J.; Chaharmir, M.R.
Improved dual-feed single-beam powercombining reflectarray antenna

Year: 2013

Abstract: The power combining efficiency of a dual-feed single-beam power combining reflectarray is shown to be substantially improved by reducing the spacing between the reflectarray elements. This improvement has been confirmed experimentally. © The Institution of Engineering and Technology 2013.

Source title: Electronics Letters

Series Number: Volume 49 Issue 25

DOI: 10.1049/el.2013.2877

Link: Improved dual-feed single-beam powercombining reflectarray antenna

Almajali, E.; McNamara, D.A.; Shaker, J.; Chaharmir, M.R.
Joint results of long-term earth-space propagation experiments at 20-GHz in Canada and Europe

Year: 2013

Abstract: Propagation effects such as rain or clouds attenuation cause deeper fades in the Ka-band than at lower frequencies. In this collaborative paper, the main results of four long-term Ka-band propagation campaigns are presented. The experiments are carried out in Ottawa, Canada; Aveiro, Portugal; Madrid, Spain; and Toulouse, France. Attenuation statistics are derived from satellite beacon data collected over 6 years at Aveiro, 5 years at Ottawa and Madrid and 2 years at Toulouse. Multi-year measurements allow the production of more stable statistics reflecting the long-term behavior of propagation phenomena and to investigate its year-to-year variability. The beacon signal data was monitored and collected on a continuous basis over the whole measurement period. After a brief introduction of the experiments, rain rate and excess attenuation results are discussed, first for a common measurement period and later for the whole database available. Seasonal attenuation statistics for Ottawa and Aveiro are compared. Finally, fade duration and fade slope statistics derived at three locations are presented and discussed. © 2009-2013 - IOS Press and the authors. All rights reserved.

Source title: Space Communications

Series Number: Volume 22

DOI: 10.3233/SC-130004

Link: Joint results of long-term earth-space propagation experiments at 20-GHz in Canada and Europe

Amaya, C.; Nguyen, T.; Rocha, A.; Riera, J.M.; Benarroch, A.; Garcia-Del-Pino, P.; Garcia-Rubia, J.M.; Carrie, G.; Castanet, L.; Boulanger, X.
Joint results of 20 GHz recent earth-space propagation experiments in Canada and Europe

Year: 2013

Abstract: Propagation effects such as rain attenuation or the influence of gases and clouds cause deeper fades in the Ka-band than at lower frequencies. Communication systems provide means to mitigate such propagation impairments, but a better experimental characterization of propagation effects can lead to better design and operation of fade mitigation techniques (FMT). In this collaborative paper, the main results of four long-term propagation campaigns are presented. The experiments are carried out in Ottawa, Canada (satellite Anik F2), Aveiro, Portugal, Madrid, Spain and Toulouse, France (satellite HotBird 6 in the last three cases).

Source title: Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP)

DOI: N/A

Link: Joint results of 20 GHz recent earth-space propagation experiments in Canada and Europe

Amaya, C.; Nguyen, T.; Rocha, JA.; Riera, J.M.; Benarroch, A.; Garcia-del-Pino, P.; Garcia-Rubia, J.M.; Carrié, G.; Castanet, L.; Boulanger, X.
High-performance, compact quasi-elliptic band pass filters for V-band high data rate radios

Year: 2013

Abstract: This paper presents a comparison of the design and implementation of V-band quasi-elliptic band pass filters suitable for system-on-package integration at millimetre-wave frequencies. Filters were designed and manufactured at low-temperature co-fired ceramic (LTCC) and alumina substrates. Filter circuits include the input/output coplanar waveguide to microstrip transitions as well as the microwave pads, used to facilitate measurement. Three four-pole filters incorporating half-wavelength resonators were implemented, two planar (on LTCC and alumina substrates) and one vertically stacked (on LTCC). In addition a six-pole filter was also implemented in alumina. The four-pole LTCC based filters have a measured insertion loss (IL) as low as 3.4 dB, fractional bandwidth (FBW(%)=BW-3 dB/Center Frequency) of 4.8% and return loss better than 10 dB. Total filter size is less than 1.1 × 0.74 mm. The alumina-based four-pole/six-pole filters exhibit a measured IL of 2.8/3.1 dB, FBW of 8.3%/12.6%, respectively. Both alumina filters exhibit a return loss better than 10 dB and with a corresponding filter layout footprint of less than 1.01 × 1.34 mm. A new figure-of-merit (HPFOM) is proposed and results from the filters proposed here clearly show they offer the best trade-off between performance and area (higher HPFOM). © 2011-2012 IEEE.

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

Series Number: Volume 3 Issue 3

DOI: 10.1109/TCPMT.2012.2232711

Link: High-performance, compact quasi-elliptic band pass filters for V-band high data rate radios

Amaya, R.E.; Momciu, A.; Haroun, I.
The circadian clock circuitry and the AHR signaling pathway in physiology and pathology

Year: 2013

Abstract: Life forms populating the Earth must face environmental challenges to assure individual and species survival. The strategies predisposed to maintain organismal homeostasis and grant selective advantage rely on anticipatory phenomena facing periodic modifications, and compensatory phenomena facing unpredictable changes. Biological processes bringing about these responses are respectively driven by the circadian timing system, a complex of biological oscillators entrained to the environmental light/dark cycle, and by regulatory and metabolic networks that precisely direct the body's adjustments to variations of external conditions and internal milieu. A critical role in organismal homeostatic functions is played by the aryl hydrocarbon receptor (AHR) complex, which senses environmental and endogenous compounds, influences metabolic responses controlling phase I/II gene expression, and modulates vital phenomena such as development, inflammation and adaptive immunity. A physiological cross-talk between circadian and AHR signaling pathways has been evidenced. The alteration of AHR signaling pathway deriving from genetic damage with polymorphisms or mutations, or produced by exogenous or endogenous AHR activation, and chronodisruption caused by mismatch between the body's internal clock and geophysical time/social schedules, are capable of triggering pathological mechanisms involved in metabolic, immune-related and neoplastic diseases. On the other hand, the molecular components of the circadian clock circuitry and AHR signaling pathway may represent useful tools for preventive interventions and valuable targets of therapeutic approaches. © 2013 Elsevier Inc.

Source title: Biochemical Pharmacology

Series Number: Volume 85 Issue 10

DOI: 10.1016/j.bcp.2013.02.022

Link: The circadian clock circuitry and the AHR signaling pathway in physiology and pathology NOTE: A login may be required to access this site.

Anderson, G.; Beischlag, T.V.; Vinciguerra, M.; Mazzoccoli, G.
A measurement-based multipath channel model for signal propagation in presence of wind farms in the UHF band

Year: 2013

Abstract: Scattering signals on wind turbines may lead to degradation problems on the communication systems provided in the UHF band, such as terrestrial television broadcasting, broadband wireless systems or public safety services. To date, despite the continuous requests from the International Telecommunication Union for studies on this field, no channel model has been developed to characterize signal propagation under these particular conditions. In response to this necessity, this paper presents a complete Tapped Delay Line (TDL) channel model to characterize multipath propagation in presence of a wind farm, including novel scattering modeling and Doppler spectra characterization. As proved later, this channel model, which is based on both theoretical development and empirical data obtained in the surroundings of a real wind farm, is adaptable to the particular features of any case under study: wind turbine dimensions, working frequency, and relative location of the wind farm, transmitter and receivers. © 1972-2012 IEEE.

Source title: IEEE Transactions on Communications

Series Number: Volume 61 Issue 11

DOI: 10.1109/TCOMM.2013.101113.130144

Link: A measurement-based multipath channel model for signal propagation in presence of wind farms in the UHF band

Angulo, I.; Montalban, J.; Canizo, J.; Wu, Y.; De La Vega, D.; Guerra, D.; Angueira, P.; Arrinda, A.
Empirical doppler characterization of signals scattered by wind turbines in the UHF band under near field condition

Year: 2013

Abstract: Time variability of the scattering signals from wind turbines may lead to degradation problems on the communication systems provided in the UHF band, especially under near field condition. In order to analyze the variability due to the rotation of the blades, this paper characterizes empirical Doppler spectra obtained from real samples of signals scattered by wind turbines with rotating blades under near field condition. A new Doppler spectrum model is proposed to fit the spectral characteristics of these signals, providing notable goodness of fit. Finally, the effect of this kind of time variability on the degradation of OFDM signals is studied. © 2013 Itziar Angulo et al.

Source title: International Journal of Antennas and Propagation

DOI: 10.1155/2013/804690

Link: Empirical doppler characterization of signals scattered by wind turbines in the UHF band under near field condition

Angulo, I.; Montalban, J.; Canizo, J.; Wu, Y.; De La Vega, D.; Guerra, D.; Angueira, P.; Arrinda, A.
On-chip single-shot and real-time self-referenced phase characterization of GHz-rate telecommunication signals

Year: 2013

Abstract: Phase Reconstruction using Optical Ultrafast Differentiation (PROUD) is implemented using an integrated Mach-Zehnder Interferometer, demonstrating self-referenced phase characterization of GHz-rate complex (up to 4-level amplitude and 4-level phase) modulation signals in a single-shot and real-time. © 2013 The Optical Society.

Source title: 2013 Conference on Lasers and Electro-Optics, CLEO 2013

DOI: 10.1364/CLEO_SI.2013.CM1G.3

Link: On-chip single-shot and real-time self-referenced phase characterization of GHz-rate telecommunication signals

Bazargani, H.P.; Quelene, J.-B.; Dumais, P.; Malacarne, A.; Clerici, M.; Morandotti, R.; Callender, C.L.; Azana, J.
Joint optimization of bit and power loading for multicarrier systems

Year: 2013

Abstract: In this letter, a novel low complexity bit and power loading algorithm is formulated for multicarrier communication systems. The proposed algorithm jointly maximizes the throughput and minimizes the transmit power through a weighting coefficient α, while meeting constraints on the target bit error rate (BER) per subcarrier and on the total transmit power. The optimization problem is solved by the Lagrangian multiplier method if the initial α causes the transmit power not to violate the power constraint; otherwise, a bisection search is used to find the appropriate α. Closed-form expressions are derived for the close-to-optimal bit and power allocations per subcarrier, average throughput, and average transmit power. Simulation results illustrate the performance of the proposed algorithm and demonstrate its superiority with respect to existing allocation algorithms. Furthermore, the results show that the performance of the proposed algorithm approaches that of the exhaustive search for the discrete optimal allocations.

Source title: IEEE Wireless Communications Letters

Series Number: Volume 2 Issue 4

DOI: 10.1109/WCL.2013.052813.130085

Link: Joint optimization of bit and power loading for multicarrier systems

Bedeer, E.; Dobre, O.A.; Ahmed, M.H.; Baddour, K.E.
Resource allocation for spectrum sharing cognitive radio networks

Year: 2013

Abstract: In this paper, we investigate the resource allocation problem (joint bit and power loading) of secondary users sharing the radio spectrum with primary users in cognitive radio networks. We consider the co-existence scenario where a secondary user is allowed to access the shared spectrum while guaranteeing tolerable interference to primary users. For such a scenario, we formulate and solve an optimization problem that jointly maximizes the secondary user throughput and minimizes its transmit power while satisfying target bit error rate per subcarrier and certain limits of co-channel and adjacent channel interferences to existing primary users. Simulation results are described that illustrate the performance of the proposed algorithm, and show its closeness to that of an exhaustive search for the equivalent discrete formulation.

Source title: IEEE International Conference on Communications

DOI: 10.1109/ICC.2013.6654957

Link: Resource allocation for spectrum sharing cognitive radio networks

Bedeer, E.; Dobre, O.A.; Ahmed, M.H.; Baddour, K.E.
A novel algorithm for rate/power allocation in OFDM-based cognitive radio systems with statistical interference constraints

Year: 2013

Abstract: In this paper, we adopt a multiobjective optimization approach to jointly optimize the rate and power in OFDM-based cognitive radio (CR) systems. We propose a novel algorithm that jointly maximizes the OFDM-based CR system throughput and minimizes its transmit power, while guaranteeing a target bit error rate per subcarrier and a total transmit power threshold for the secondary user (SU), and restricting both co-channel and adjacent channel interferences to existing primary users (PUs) in a statistical manner. Since the interference constraints are met statistically, the SU transmitter does not require perfect channel-state-information (CSI) feedback from the PUs receivers. Closed-form expressions are derived for bit and power allocations per subcarrier. Simulation results illustrate the performance of the proposed algorithm and compare it to the case of perfect CSI. Further, the results show that the performance of the proposed algorithm approaches that of an exhaustive search for the discrete global optimal allocations with significantly reduced computational complexity.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2013.6831616

Link: A novel algorithm for rate/power allocation in OFDM-based cognitive radio systems with statistical interference constraints

Bedeer, E.; Dobre, O.A.; Ahmed, M.H.; Baddour, K.E.
Feasibility of a Millimeter-Wave MIMO System for Short-Range Wireless Communications in an Underground Gold Mine

Year: 2013

Abstract: The performance of multiple-input-multiple-output (MIMO) system operating at the 60 GHz band is investigated based on experimental data in a real underground mine gallery. However, the millimeter wave (mmW) channels face some challenges such as high propagation loss. In order to overcome this issue, a planar microstrip antenna array has been designed, and fabricated. Moreover, the effect of miners' activity in the vicinity of the short-range wireless link is studied. Statistical parameters of the propagation channel, such as RMS delay spread, path loss, K-factor, channel correlation and capacity are extracted and analyzed. Results suggest that miners presence substantially affects both received power and time dispersion parameters and should therefore be considered when developing underground mine wireless networks in the unlicensed 60-GHz band. © 1963-2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 61 Issue 8

DOI: 10.1109/TAP.2013.2259454

Link: Feasibility of a Millimeter-Wave MIMO System for Short-Range Wireless Communications in an Underground Gold Mine

Ben Mabrouk, S.; Talbi, L.; Nedil, M.; Hettak. K.
Improvement of the tile format for stereoscopic video

Year: 2013

Abstract: Tile format is a new frame packing arrangement for the first generation of 3D TV broadcasting services. It puts the left- and right-eye images of each stereoscopic image pair into a single composition frame that allows the service provider to reuse existing production and distribution infrastructure for offering 3D TV services. Different from frame compatible formats, the tile format composition does not down-sample the left- and right-eye images and, thus, provides a higher video quality for both 3D and 2D display. The problem with the tile format is that it creates artificial edges in the right-eye image and introduces visible tiling artifacts around the artificial edges after compression. This paper presents a simple modification to the tile format composition method that significantly reduces the tiling artifacts. Experimental results show that local PSNRs around artificial edges are improved by over 1dB. © 2013 IEEE.

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

DOI: 10.1109/BMSB.2013.6621705

Link: Improvement of the tile format for stereoscopic video

Blanchfield, P.; Wang, D.
Power and spectrally efficient communications: A comparison of linear and non-linear modulation schemes

Year: 2013

Abstract: This paper compares linear and non-linear modulation schemes for both bandwidth-limited and power-limited scenarios. In particular, we discuss the various trade-offs in terms of spectral efficiency, signal-to-noise ratio requirements and transmission range when selecting a candidate modulation scheme. Examples of the trade-offs are shown for maximising transmission range in frequency non-selective fading channels. © 2013 SPIE.

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

DOI: 10.1117/12.2013826

Link: Power and spectrally efficient communications: A comparison of linear and non-linear modulation schemes

Brown, C.; Vigneron, P.J.
Medium access control for Unmanned Aerial Vehicle (UAV) ad-hoc networks with full-duplex radios and multipacket reception capability

Year: 2013

Abstract: Recent advances in interference cancellation and signal-processing techniques can enable full-duplex radios and multipacket reception (MPR), which will have significant impact on medium access control (MAC) schemes. In this paper, we propose a MAC scheme in unmanned aerial vehicle (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 to update information in the network as well. The MAC schemes in the presence of perfect and imperfect channel state information (CSI) are formulated as a combinatorial optimization problem and a discrete stochastic optimization problem, respectively. Simulation results show the effectiveness of the proposed MAC. © 2012 IEEE.

Source title: IEEE Transactions on Vehicular Technology

Series Number: Volume 62 Issue 1

DOI: 10.1109/TVT.2012.2211905

Link: Medium access control for Unmanned Aerial Vehicle (UAV) ad-hoc networks with full-duplex radios and multipacket reception capability

Cai, Y.; Yu, F.R.; Li, J.; Zhou, Y.; Lamont, L.
A multiband military communication antenna

Year: 2013

Abstract: The Canadian Forces have procured X-band and military Ka-band satellite capacity on the USA Wideband Global Satellite (WGS) system. Currently available terminals can operate in each of these bands with some of them providing a manually switchable front end to change the band of operation. The Communications Research Centre Canada (CRC) has developed different multi-band reflectarray antennas as satellite terminal in the last decade [1-3]. These reflectarray antennas provide simultaneous communication in multiple bands henceforth the flexibility to transmit in one band and receive in the other band. In this paper, we present the challenges involved in the design and operation of a particular reflectarray configuration for a multi-band terminal application. The pros and cons of this mutli-band reflectarray antenna are presented and different alternatives to overcome the disadvantage of this design are discussed.

Source title: 31st AIAA International Communications Satellite Systems Conference, ICSSC 2013

DOI: 10.2514/6.2013-5689

Link: A multiband military communication antenna

Chaharmir, R.; Caron, M.; Shaker, J.; Petosa, A.
Particle-in-cell/Monte Carlo collision simulation of the ionization process of surface-wave plasma discharges resonantly excited by surface plasmon polaritons

Year: 2013

Abstract: Although surface-wave plasma (SWP) sources have many industrial applications, the ionization process for SWP discharges is not yet well understood. The resonant excitation of surface plasmon polaritons (SPPs) has recently been proposed to produce SWP efficiently, and this work presents a numerical study of the mechanism to produce SWP sources. Specifically, SWP resonantly excited by SPPs at low pressure (0.25 Torr) are modeled using a two-dimensional in the working space and three-dimensional in the velocity space particle-in-cell with the Monte Carlo collision method. Simulation results are sampled at different time steps, in which the detailed information about the distribution of electrons and electromagnetic fields is obtained. Results show that the mode conversion between surface waves of SPPs and electron plasma waves (EPWs) occurs efficiently at the location where the plasma density is higher than 3.57 × 1017 m3. Due to the effect of the locally enhanced electric field of SPPs, the mode conversion between the surface waves of SPPs and EPWs is very strong, which plays a significant role in efficiently heating SWP to the overdense state. © 2013 American Institute of Physics.

Source title: Physics of Plasmas

Series Number: Volume 20 Issue 3

DOI: 10.1063/1.4794736

Link: Particle-in-cell/Monte Carlo collision simulation of the ionization process of surface-wave plasma discharges resonantly excited by surface plasmon polaritons

Chen, Z.; Ye, Q.; Xia, G.; Hong, L.; Hu, Y.; Zheng, X.; Li, P.; Zhou, Q.; Hu, X.; Liu, M.
jFuzzyLogic: A Java Library to Design Fuzzy Logic Controllers According to the Standard for Fuzzy Control Programming

Year: 2013

Abstract: Fuzzy Logic Controllers are a specific model of Fuzzy Rule Based Systems suitable for engineering applications for which classic control strategies do not achieve good results or for when it is too difficult to obtain a mathematical model. Recently, the International Electrotechnical Commission has published a standard for fuzzy control programming in part 7 of the IEC 61131 norm in order to offer a well defined common understanding of the basic means with which to integrate fuzzy control applications in control systems. In this paper, we introduce an open source Java library called jFuzzyLogic which offers a fully functional and complete implementation of a fuzzy inference system according to this standard, providing a programming interface and Eclipse plugin to easily write and test code for fuzzy control applications. A case study is given to illustrate the use of jFuzzyLogic. © 2013 Copyright the authors.

Source title: International Journal of Computational Intelligence Systems

Series Number: Volume 6 Supplement 1

DOI: 10.1080/18756891.2013.818190

Link: jFuzzyLogic: A Java Library to Design Fuzzy Logic Controllers According to the Standard for Fuzzy Control Programming

Cingolani, P.; Alcala-Fdez, J.
Spatial hopping in MIMO systems for impeded signal reception by multi-element Eavesdroppers

Year: 2013

Abstract: In multiple-input multiple-output (MIMO) systems employing precoding, knowledge of the precoding matrices used is essential for successful reception. Herein, a method is proposed to reduce the ability of a third-party eavesdropper to successfully receive precoded MIMO signals. Rather than precoding with the exact precoding matrices chosen by the intended receiver, transmission occurs by sequentially precoding using a set of precoding matrices clustered around the chosen precoding matrix. This is shown to significantly degrade eavesdropper reception while maintaining performance for the desired user. © 2013 IEEE.

Source title: IEEE Wireless Communications Letters

Series Number: Volume 2 Issue 6

DOI: 10.1109/WCL.2013.090313.130435

Link: Spatial hopping in MIMO systems for impeded signal reception by multi-element Eavesdroppers

Colman, G.W.K.
Comparative evaluation of macrocellular and in-building wireless coverage performance at 700 and 2500 MHz

Year: 2013

Abstract: Results are presented of an evaluation of relative macrocellular and in-building wireless signal coverage performance at 700 and 2500 MHz, based on physically-based propagation prediction data and measurements of in-building propagation path loss. Macrocellular area coverage at 700 MHz was found to be 2-3 times larger than that at 2500 MHz. The mean in-building path loss advantage of 700 MHz over 2500 MHz was found to be at best marginally (1 dB) higher than the outdoor advantage at street level. These results indicate that the lower free-space and material penetration losses at 700 MHz are counteracted, to varying but significant degree, by an increased probability of Fresnel zone blockage. © 2013 EurAAP.

Source title: 2013 7th European Conference on Antennas and Propagation, EuCAP 2013

DOI: N/A

Link: Comparative evaluation of macrocellular and in-building wireless coverage performance at 700 and 2500 MHz

De Jong, Y.L.C.; Rogers, D.V.
Audio tampering localization using modified iss watermarking in sparse-domain

Year: 2013

Abstract: This paper presents a blind audio tampering localization method in the perceptual sparse domain using a novel Modified Improved Spread Spectrum (MISS) watermarking approach. Current methods of audio authentication lack the ability to localize the tampered part of the audio in the presence of desynchronization attacks such as time shifting, scaling, etc. Our proposed method is able to localize the highly modified parts and then self-synchronize. To achieve this goal, Perceptual Matching Pursuit is used to compute a sparse and time-shift invariant representation of audio signals as well as 2-D masking thresholds. Then authentication code is inserted as a hidden watermark inside the sparse coefficient. To localize the tampered part of audio, the presence of watermark is detected inside the frames of input signal. To guarantee the high quality of watermarked audio, the watermark data is shaped by masking thresholds. To achieve high capacity, we propose a modified version of improved spread spectrum watermarking. In comparison to the conventional methods, experiments confirm the superiority of our approach in localizing the tampered parts of the audio and also confirm the high capacity of MISS signature insertion while preserving good audio quality. © 2013 IEEE.

Source title: 2013 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2013 - Proceedings

DOI: 10.1109/GlobalSIP.2013.6736862

Link: Audio tampering localization using modified iss watermarking in sparse-domain

Erfani, Y.; Pichevar, R.; Rouat, J.
Using rotatable planar phase shifting surfaces to steer a high-gain beam

Year: 2013

Abstract: Phase shifting surface (PSS) technology has been used to develop a 30 GHz beam steering antenna. The concept is similar to that of a pair of dielectric wedges placed in front of a primary antenna for beam steering. The initial prototype antenna is made of a horn-fed PSS phase-correcting Fresnel zone plate above which are placed two rotatable circular linear phase progression PSSs. These PSSs have rotation capability along their planes. Their rotation allows for achieving beam steering in the upper hemisphere. An additional prototype antenna makes use of a rotatable offset-beam PSS phase-correcting Fresnel zone plate and a single linear phase progression PSS to achieve beam steering with a higher aperture efficiency. These prototypes confirm the feasibility of using PSS technology for achieving a lightweight, low-cost and efficient beam steering antenna. © 2013 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 61 Issue 6

DOI: 10.1109/TAP.2013.2253298

Link: Using rotatable planar phase shifting surfaces to steer a high-gain beam

Gagnon, N.; Petosa, A.
Research and development on phase-shifting surfaces (PSSs)

Year: 2013

Abstract: Phase-shifting surfaces (PSSs) developed in recent years are reported. Research and development on these phase-shifting surfaces are set in the historical context of prior-art free-standing lensing devices, as well as in the context of recent studies performed by other research groups. In addition, initial work on a phase- and amplitude-shifting surface (PASS), an extension of the phase-shifting surface, is demonstrated in a beam-shaping application. © 2013 IEEE.

Source title: IEEE Antennas and Propagation Magazine

Series Number: Volume 55 Issue 2

DOI: 10.1109/MAP.2013.6529314

Link: Research and development on phase-shifting surfaces (PSSs)

Gagnon, N.; Petosa, A.; McNamara, D.A.
Comparison of 2-, 3- and 4-layer phase shifting surface lens antennas

Year: 2013

Abstract: Phase shifting surface lenses made of different numbers of conductive layers are designed for antenna applications at Ka band. They consist of a 2-layer hybrid lens, a 3-layer quasi-continuous Fresnel lens and a 4-layer continuous Fresnel lens. Prototypes for each of these lenses are fabricated and measured. A comparison of the results is presented. © 2013 IEEE.

Source title: 2013 IEEE Antennas and Propagation Society International Symposium (APSURSI)

DOI: 10.1109/APS.2013.6711244

Link: Comparison of 2-, 3- and 4-layer phase shifting surface lens antennas

Gagnon, N.; Petosa, A.; McNamara, D.A.
GPS phase difference variation statistics: A comparison between phase scintillation index and proxy indices

Year: 2013

Abstract: Scintillated GPS phase observations are traditionally characterized by the phase scintillation index, derived from specialized GPS receivers usually tracking at 50 Hz. Geodetic quality GPS receivers, on the other hand, are normally tracking at frequencies up to 1 Hz. However, availability of continuously operating geodetic receivers both in time and geographical location are superior to scintillation receiver's coverage in many parts of the world. This motivates scintillation studies using regional and global geodetic GPS networks. Previous studies have shown the usefulness of GPS estimated total electron content variations for detecting ionospheric irregularities. In this paper, collocated geodetic and scintillation receivers are employed to compare proxy indices derived from geodetic receivers with the phase scintillation index during quiet and moderately disturbed ionospheric conditions. Sensitivity of the phase scintillation indices at high latitude stations to geomagnetic activity is discussed. Global mapping of ionospheric disturbances using proxy indices from real-time 1 Hz GPS stations are also presented. © 2013 COSPAR. Published by Elsevier Ltd. All rights reserved.

Source title: Advances in Space Research

Series Number: Volume 52 Issue 8

DOI: 10.1016/j.asr.2013.06.035

Link: GPS phase difference variation statistics: A comparison between phase scintillation index and proxy indices NOTE: A login may be required to access this site.

Ghoddousi-Fard, R.; Prikryl, P.; Lahaye, F.
The capacity region of a product of two unmatched physically degraded gaussian broadcast channels with three individual messages and a common message

Year: 2013

Abstract: This paper considers a Gaussian broadcast channel with two unmatched degraded components, three individual messages, and a common message that is intended for all three receivers. It is shown that for this channel, superposition coding with Gaussian signalling is sufficient to achieve every point in the capacity region. © 2012 IEEE.

Source title: IEEE Transactions on Information Theory

Series Number: Volume 59 Issue 1

DOI: 10.1109/TIT.2012.2219172

Link: The capacity region of a product of two unmatched physically degraded gaussian broadcast channels with three individual messages and a common message

Gohary, R.H.; Davidson, T.N.
Laser cavity made with ultrafast IR type II gratings in heavily doped Er-Yb fiber

Year: 2013

Abstract: We are reporting for the first time a laser cavity built in heavily doped Er-Yb fiber with type II Bragg gratings mirrors made with IR femtosecond radiation using the phase mask method. © 2010 Optical Society of America.

Source title: Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides, BGPP 2012

DOI: 10.1364/BGPP.2012.BW3E.2

Link: Laser cavity made with ultrafast IR type II gratings in heavily doped Er-Yb fiber

Grobnic, D.; Mihailov, S.J.; Walker, R.B.; Smelser, C.W.
Reflection characteristics of type II FBG made with femtosecond radiation

Year: 2013

Abstract: We have designed an experiment to show that in spite of the broadband loss along the grating, type II gratings manifest low loss in a reflective configuration. © 2010 Optical Society of America.

Source title: Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides, BGPP 2012

DOI: 10.1364/BGPP.2012.BM2D.5

Link: Reflection characteristics of type II FBG made with femtosecond radiation

Grobnic, D.; Mihailov, S.J.; Walker, R.B.; Smelser, C.W.
Feasibility Study of Optically Transparent CPW Fed Monopole Antenna at 60-GHz ISM Bands

Year: 2013

Abstract: This paper presents a feasibility study on an optically transparent planar monopole lozenge antenna at the 60-GHz industrial-scientific-medical (ISM) band. The feeding of this antenna is composed of a 50-Ω meshed coplanar waveguide. The size of the proposed antenna is around 2.3×2.3 mm2. The transparent and conductive material used to fabricate the proposed antenna is made of a gold grid layer deposited on a 0.2-mm-thick fused silica 7980 Corning substrate. The theoretical transparency equals 83% with a sheet resistance of 0.44 Ω/sq. The simulated and measured results of the transparent monopole antenna are compared to a nontransparent (but identical) antenna. It was found that both antennas have the same performances in terms of bandwidth, radiation pattern, and gain. The measurements show the same behavior for transparent and nontransparent antennas. These results confirm the absence of ohmic and skin depth losses in the gold grid layer at 60-GHz ISM bands and provide the possibility of implementing transparent antennas with performances absolutely identical to the nontransparent ones, with the advantage of a soft visual impact. © 1963-2012 IEEE.

Source title: IEEE Transactions on Antennas and Propagation

Series Number: Volume 61 Issue 4

DOI: 10.1109/TAP.2012.2232265

Link: Feasibility Study of Optically Transparent CPW Fed Monopole Antenna at 60-GHz ISM Bands

Hautcoeur, J; Talbi, L.; Hettak, K.
A new family of low correlation zone sequences in QS-CDMA communication systems

Year: 2013

Abstract: The paper addresses the problem of constructing signature sequences for quasi-synchronous CDMA systems. We employ two -ary sequences, i.e. symbols sequences, with ideal two-level autocorrelation and a Costas or Golomn Costas sequence to construct a signal set with long Low Correlation Zone length and low maximum magnitude of correlation values. We obtain an Low Correlation Zone (Np, p, p, N) signal set and an Low Autocorrelation Zone (Np, p, p, N) signal set, where N is a positive integer and p is a prime number. We also get an LCZ (pm(pm − 1), pm − 1, pm) signal set and an LACZ (pm(pm − 1), pm, pm − 1, 1) signal set, where m is a positive integer. © 2013 IEEE.

Source title: 2013 IEEE International Wireless Symposium, IWS 2013

DOI: 10.1109/IEEE-IWS.2013.6616740

Link: A new family of low correlation zone sequences in QS-CDMA communication systems

He, J.J.; Zeng, Q.
Design of 60-GHz CPW fed patch antenna for Switched-beam antenna array

Year: 2013

Abstract: A simple and compact 60 GHz CPW-fed patch antenna for Switched-beam antenna array applications is presented and investigated. The proposed antenna with a small size of 700 µm × 720 µm is composed of a rectangular strip radiation element fed by a CPW feed line. The proposed antenna has been successfully designed. The simulated results show that the antenna achieves a wide impendence bandwidth from 58 to 62 GHz with return loss less than -10 dB. © 2013 IEEE.

Source title: 2013 IEEE Antennas and Propagation Society International Symposium (APSURSI)

DOI: 10.1109/APS.2013.6711365

Link: Design of 60-GHz CPW fed patch antenna for Switched-beam antenna array

Hettak, K.; Delisle, G.Y.; Talbi, L.
Miniature single-sideband subharmonically-pumped 60 GHz direct upconverter in a uniplanar GaAs pHEMT technology using inductive and capacitive loading techniques

Year: 2013

Abstract: This paper presents a novel, compact, single-sideband (SSB) subharmonically-pumped (SHP) direct upconverter developed in a uniplanar 0.18 µm GaAs technology. A total of 100 MHz in-phase and quadrature signals directly modulate the second harmonic of a 30 GHz carrier signal, producing a 60.1 GHz output. Two pairs of antiparallel diodes reduce feed-through of the 30 GHz local oscillator (LO) signal to the mixer's RF output. Novel structures patterned in the center conductor of a coplanar waveguide (CPW) provide matching and size-reduction simultaneously. The 2.1mm2 circuit also uses a miniaturized Wilkinson divider based on asymmetric coplanar stripline and a standard CPW 90° coupler. The SSB SHP direct upconverter exhibits a conversion loss of 10 dB, a lower-sideband rejection of 15 dB and 2fLO suppression of approximately 25 dB over a wide frequency range from 52-61 GHz. © Cambridge University Press and the European Microwave Association, 2013.

Source title: International Journal of Microwave and Wireless Technologies,

Series Number: Volume 5 Special Issue 3

DOI: 10.1017/S1759078713000330

Link: Miniature single-sideband subharmonically-pumped 60 GHz direct upconverter in a uniplanar GaAs pHEMT technology using inductive and capacitive loading techniques

Hettak, K.; Ross, T.; Cormier, G.
Flexible polyethylene terephthalate-based inkjet printed CPW-fed monopole antenna for 60 GHz ISM applications

Year: 2013

Abstract: This study investigates an inkjet-printed millimetre-wave antenna on Polyethylene Terephthalate (PET) substrate. The 60 GHz CPW-fed monopole antenna was printed with a DMP-2800 series inkjet printing system. A silver nanoparticle colloidal solution was used as the printing ink. First, this process uses a plasma polymerization technique to improve the PET surface or printing. Then, silver lines are inkjet printed on the PET substrate, followed by curing in an oven to remove excess solvent and material impurities. The multiple-pass lines are printed to study the changes in surface roughness and line width. The silver film conductivity of the conductive ink is around 4 × 106 S/m. The measured impedance bandwidth of the printed antenna, defined by return loss less than -10 dB, is from 60 to 65 GHz. © 2013 EuMA.

Source title: European Microwave Week 2013, EuMW 2013 - Conference Proceedings; EuMIC 2013: 8th European Microwave Integrated Circuits Conference

DOI: N/A

Link: Flexible polyethylene terephthalate-based inkjet printed CPW-fed monopole antenna for 60 GHz ISM applications

Hettak, K.; Ross, T.; James, R.; Momciu, A.; Wight, J.
Broadband high-power GaN SPDT switch using stacked-shunt fets and resonance inductors

Year: 2013

Abstract: This article presents a new GaN HEMT-based high-power single-pole double-throw (SPDT) switch operating over the X-band frequencies. The GaN SPDT MMIC switch is presented, having good return loss (better than 16.8 dB) and insertion loss (1.4 dB) measured across X-band. It also has a very high power-handling capability, with a measured 1 dB compression point of 38 dBm. The techniques and design principles leading to this level of performance are discussed. Circuit performance is confirmed by experimental and simulation results, which are in good agreement up to 20 GHz. © 2013 Wiley Periodicals, Inc.

Source title: Microwave and Optical Technology Letters

Series Number: Volume 55 Issue 9

DOI: 10.1002/mop.27788

Link: Broadband high-power GaN SPDT switch using stacked-shunt fets and resonance inductors

Hettak, K.; Ross, T.N.; Cormier, G.; Wight, J.S.
Multi-carrier LINC amplifier calibration by min-minimum criterion

Year: 2013

Abstract: In this paper, we briefly introduce the LINC amplifier, and discuss its mismatch issues that reduce its linearity and degrade its performance. A calibration approach for the LINC amplifier is proposed for multi-carrier system applications such as OFDM systems. The technique estimates the LINC amplifier calibration coefficient from the LINC amplifier output signal envelope by using a min-minimum criterion. Computer simulations are carried out to validate the proposed LINC amplifier calibration approach. It is demonstrated that the calibration coefficient can be accurately determined, and the mismatch compensated, by the proposed approach, so that the LINC amplifier performance can be significantly improved. © 2013 IEEE.

Source title: Proceedings - IEEE International Symposium on Circuits and Systems

DOI: 10.1109/ISCAS.2013.6572051

Link: Multi-carrier LINC amplifier calibration by min-minimum criterion

Huang, X.; Caron, M.
Optimization of ATSC mobile handheld service capacity

Year: 2013

Abstract: Mobile TV has become a reality offered on several mobile delivery systems. Among them is the Advanced Television System Committee (ATSC) system for mobile and handheld digital television services, known as ATSC Mobile DTV or ATSC M/H, which has moved from standardization to implementation. As the North American broadcast industry is preparing to provide Mobile DTV service to consumers, this work discusses important technical parameters that affect the TV service quality and capacity. Since additional error correction mechanisms were added to overcome mobile transmission problems, the available payload for M/H services is limited. This creates a need to efficiently use the available M/H bandwidth. The paper aims to optimize the Mobile DTV service capacity while maintaining an acceptable perceived quality. It presents tradeoffs between several factors affecting service capacity and signal robustness, which is prominent for designing Mobile TV broadcasting scenarios. © 2013 Omneya Issa.

Source title: International Journal of Digital Multimedia Broadcasting

Series Number: Volume 2013

DOI: 10.1155/2013/837153

Link: Optimization of ATSC mobile handheld service capacity

Issa O.
Inference of Network Impairment Effect on the Quality of High Definition IPTV Distribution

Year: 2013

Abstract: High Definition content delivery over IP networks has become a reality in the entertainment market. However, such networks are subject to packet loss, especially on the last mile link. This paper presents a roadmap for predicting the packet loss effect on the quality rating. The quality of the delivered video was evaluated objectively in IPTV emulated environment subject to loss impairments. Objective measurements were validated by subjective assessments. High correlating models were developed for the prediction of overall user judgment based on objective and instantaneous perceived quality of impaired HD IPTV. Guidelines were also drawn for estimating viewers' instantaneous responses.

Source title: International Journal of Information Technology, Communications and Convergence

Series Number: Volume 2 Issue 4

DOI: 10.1504/IJITCC.2013.059399

Link: Inference of Network Impairment Effect on the Quality of High Definition IPTV Distribution

Issa, O.; Speranza, F.; Li, W.; Liu, H.
Visual importance- and discomfort region-selective low-pass filtering for reducing visual discomfort in stereoscopic displays

Year: 2013

Abstract: In human vision, the depth of focus (DOF) blur is important to perceive single binocular vision. Unfortunately, conventional stereoscopic displays cannot provide a natural DOF blur effect. Synthetic DOF blur that simulates the natural DOF blur effect could be useful for reducing the visual discomfort in stereoscopic displays. However, the incorrect introduction of artificial blur in the image might also have negative effects. This paper proposes a selective DOF blur technique that is applied only to local regions that induce high visual discomfort but are less visually important. We employ a visual importance analysis to obtain reasonable estimates of the areas/objects that are likely to be attended using saliency maps. After identifying the regions likely to cause discomfort because of excessive relative disparity, we apply low-pass filtering for the less-salient neighboring pixels of the discomfort regions. We demonstrate that the DOF blur simulation for less important background regions that induce visual discomfort is helpful in reducing the visual discomfort in stereoscopic viewing. © 1991-2012 IEEE.

Source title: IEEE Transactions on Circuits and Systems for Video Technology

Series Number: Volume 23 Issue 8

DOI: 10.1109/TCSVT.2013.2244796

Link: Visual importance- and discomfort region-selective low-pass filtering for reducing visual discomfort in stereoscopic displays

Jung, Y.J.; Sohn, H.; Lee, S.-I.; Speranza, F.; Ro, Y.M.
Parametric study of 1-D PBG structures composed of subwavelength dipole elements

Year: 2013

Abstract: In this letter, an original approach for filter design using one-dimensional photonic band-gap (1-D PBG) structures composed of subwavelength dipole elements is presented. Through an efficient S - to T - parameters conversion technique, a detailed analysis is performed to investigate the variation of the dispersion characteristics of 1-D PBG structures as a function of the cell element configuration. Also, for the first time, the angular sensitivity of the structure has been studied in order to obtain the projected band diagrams for both TE and TM polarizations. © 2002-2011 IEEE.

Source title: IEEE Antennas and Wireless Propagation Letters

Series Number: Volume 12

DOI: 10.1109/LAWP.2013.2263493

Link: Parametric study of 1-D PBG structures composed of subwavelength dipole elements

Khodami, M.; Shaker, J.; Yagoub, M.C.E.
Efficient broadcasting in tactical networks: The impact of local topology information accuracy

Year: 2013

Abstract: Broadcasting (communicating information from one to all or many to all nodes in a network) is an important communication primitive in tactical networks. To reduce the spectral cost of such protocols, instead of using simple flooding, many proposed broadcast protocols such as the Simplified Multicast Forwarding (SMF) employ the local topology information to reduce the number of packet rebroadcasts. The performance of such optimizations depends on the accuracy of the topology information. In this work, we explore how well SMF functions in the presence of inaccurate local topology information due to mobility and the probabilistic nature of wireless transmissions. Our results show that SMF performs very poorly when these effects combine. The typical extensions of QoS improvements for SMF are found to incur significantly higher protocol overheads and can only partially enhance its delivery ratio. © 2013 IEEE.

Source title: Proceedings - IEEE Military Communications Conference MILCOM

DOI: 10.1109/MILCOM.2013.229

Link: Efficient broadcasting in tactical networks: The impact of local topology information accuracy

Kunz, T.; Li, L.
Effect of stimulus width on the perceived visual discomfort in viewing stereoscopic 3-D-TV

Year: 2013

Abstract: To address the issues of viewing safety in stereoscopic three-dimensional television, it is important to investigate determinants of visual discomfort in viewing stereoscopic images. In stereoscopic viewing, it is well known that visual discomfort can be induced by excessive binocular disparity, fast changes in binocular disparity, and binocular asymmetry. However, subjective sensation of visual discomfort could also be substantially different depending on other characteristics of visual stimulus given the complexity of the visual system. From previous studies that have investigated the relation between stimulus characteristics and binocular fusion limit, we speculate that stimulus width (i.e., object width in the stereoscopic scene) can also affect the perceived visual discomfort of stereoscopic images. This paper investigates the effect of stimulus width on visual discomfort by measuring subjective visual discomfort and binocular fusion time. Experimental results show that smaller stimulus width could induce more visual discomfort and increase binocular fusion time. © 1963-12012 IEEE.

Source title: IEEE Transactions on Broadcasting

Series Number: Volume 59 Issue 4

DOI: 10.1109/TBC.2013.2268713

Link: Effect of stimulus width on the perceived visual discomfort in viewing stereoscopic 3-D-TV

Lee, S.-I.; Jung, Y.J.; Sohn, H.; Speranza, F.; Ro, Y.M.
Communication architectures and protocols for networking unmanned aerial vehicles

Year: 2013

Abstract: A fundamental but challenging problem in cooperation and control of multiple unmanned aerial vehicles (UAVs) is efficient networking of the UAVs over the wireless medium in rapidly changing environments. In this paper, we introduce four communication architectures for networking UAVs and review some military communication standards applicable to UAV communications. After discussions of pros and cons of each communication architecture, we conclude that a UAV ad hoc network is the most appropriate architecture to network a team of UAVs, while a multi-layer UAV ad hoc network is more suitable for multiple groups of heterogeneous UAVs. By comparing various legacy and next-generation military data link systems, we highlight that one important feature of the next-generation waveforms is their capability of Internet protocol (IP) based ad hoc networking, which allows UAVs to communicate with each other in a single- or multi-layer UAV ad hoc networks. © 2013 IEEE.

Source title: 2013 IEEE Globecom Workshops, GC Wkshps 2013

DOI: 10.1109/GLOCOMW.2013.6825193

Link: Communication architectures and protocols for networking unmanned aerial vehicles

Li, J.; Zhou, Y.; Lamont, L.
A token circulation scheme for code assignment and cooperative transmission scheduling in CDMA-based UAV ad hoc networks

Year: 2013

Abstract: Code division multiple access (CDMA) ad hoc networks have been considered a promising multiple-channel networking architecture for connecting tactical platforms in battle fields. In this paper we consider a network of a swarm of unmanned aerial vehicles (UAVs) that are used in a tactical surveillance mission. The UAVs are assumed to have multiuser detection capability and form a CDMA-based ad hoc network. A token circulation scheme is proposed to conduct functions required at the medium access control layer including detection of hidden/lost neighbors, code assignment and schedule-based cooperative transmission scheduling. In the proposed scheme, a token continuously circulates around the network based on the "receive-forward" module. Through circulation of the token, each UAV can detect its hidden and/or lost neighbors in near real-time, assign codes enabling the spatial reuse of code channels without incurring code collision, and schedule data transmissions in a cooperative and distributed manner. In addition, the proposed scheme is able to take advantage of multiuser detection functionality and allows for simultaneous transmissions from multiple transmitters to a same receiver. The performance of the proposed token circulation scheme is evaluated, both analytically and through simulations. It is shown that the latency of the token is at most linearly proportional to the network size, and the average delay of a data packet increases with either the packet generation rate or the network size. The results also show that the proposed token circulation scheme is suitable for large-scale CDMA-based UAV ad hoc networks with even heavy network traffic load. © 2013 Her Majesty the Queen in Rights of Canada.

Source title: Wireless Networks

Series Number: Volume 19 Issue 6

DOI: 10.1007/s11276-013-0545-5

Link: A token circulation scheme for code assignment and cooperative transmission scheduling in CDMA-based UAV ad hoc networks

Li, J.; Zhou, Y.; Lamont, L.; Deziel, M.
Packet delay in UAV wireless networks under non-saturated traffic and channel fading conditions

Year: 2013

Abstract: In this paper, we conduct a statistical analysis for the packet delay in a wireless network of unmanned aerial vehicles (UAVs) under non-saturated traffic and channel fading conditions. Each UAV runs the distributed coordination function of IEEE 802.11 at the medium access control layer, and all UAVs are one-hop neighbors. A pair of UAVs can communicate over the lossy wireless channel of a fixed data rate. A non-saturated traffic condition is used. By modeling each node UAV as a standard queueing system (i.e.; M/M/1 or M/G/1 queue), we derive the mean packet delay under the non-saturated traffic condition. Numerical and simulation results show that the mean packet delay derived based on M/M/1 queue is accurate for UAV wireless networks under the non-saturated traffic condition and with an independent packet error rate. It is observed that the mean packet delay increases with either the number of UAVs in the network or the packet generation rate. More important, existing results in the literature, based on the saturated traffic condition (i.e.; packets are always supplied for transmission), tend to overestimate by a large amount the mean packet delay for networks with non-saturated traffic. In the second part of this paper, we apply simulation data to analysis of the probability distribution function of the packet delay when the packet error rate equals zero. Using a distribution fitting tool, we observe that the packet delay can be well approximated by the sum of a deterministic delay, which corresponds to the time period during which the UAV senses the medium and is able to perform a successful transmission, and a random delay, which follows a Gamma distribution function. © 2013 Her Majesty the Queen in Right of Canada.

Source title: Wireless Personal Communications

Series Number: Volume 72 Issue 2

DOI: 10.1007/s11277-013-1057-4

Link: Packet delay in UAV wireless networks under non-saturated traffic and channel fading conditions

Li, J.; Zhou, Y.; Lamont, L.; Toulgoat, M.; Rabbath, C.A.
A dual-mode CPW resonator for 60 GHz broadband standing-wave VCO applications

Year: 2013

Abstract: A novel dual-mode modified differential coplanar waveguide (CPW) resonator, which can be used in millimeter-wave broad-band VCO designs, is presented. A fully-integrated 60 GHz standing-wave VCO based on this new structure was designed, manufactured, and tested. The circuit was fabricated in a 90-nm CMOS technology. The design and measurement results demonstrated that using this new standing-wave resonator with dual-mode differential CPW topology, instead of a traditional LC-tank, can reduce the VCO size, increase the tuning range, and lower the phase noise. Measured results show that the VCO can achieve a tuning range of 7.5%, a Figure Of Merit (FOM) of -183.9 dBc/Hz @10 kHz, and a compact size as small as 350 µm × 550 µm. © 2013 IEEE.

Source title: IEEE MTT-S International Microwave Symposium Digest

DOI: 10.1109/MWSYM.2013.6697453

Link: A dual-mode CPW resonator for 60 GHz broadband standing-wave VCO applications

Li, M.; Amaya, R.E.; Momciu, A.; Hettak, K.
Study on DC-driven air cold plasma brushes generated without airflow supplement

Year: 2013

Abstract: In this paper, 30-mm-wide cold atmospheric-pressure air plasma brushes are reported. The brushes driven by a direct current power supply are capable of generating air plasma glows with no noble gas addition and no airflow supplement. There is no risk of glow-to-arc transitions, and the plasma glow appears uniform no matter what kinds of material are being processed. The air plasma glow can be scaled up by using the plasma brush arrays. About 30 mm × 30mm × 5mm (W, H, and L) homogeneous air plasma glow is generated by merging seven-brush arrays. Current measurements show that the single-brush discharge appears periodically pulsed, while the brush array discharge actually presents either pulsed with about array-number-times frequency of the single one. A further analysis indicates that the charge particles trapped along the dielectric surface may be responsible for the discharges. © 1973-2012 IEEE.

Source title: IEEE Transactions on Plasma Science

Series Number: Volume 41 Issue 3

DOI: 10.1109/TPS.2013.2245348

Link: Study on DC-driven air cold plasma brushes generated without airflow supplement

Li, P.; Chen, Z.; Xia, G.; Hong, L.; Xu, G.; Zheng, X.; Hu, Y.; Wang, Q.; Ye, Q.; Liu, M.
A reconfigurable wide slot antenna integrated with sirs for UWB/multiband communication applications

Year: 2013

Abstract: A reconfigurable wide slot antenna integrated with stepped impedance resonators (SIRs) and ideal switches for ultra-wideband (UWB) and multiband communication applications is proposed. The proposed reconfigurable antenna can be used as a UWB antenna, a dual notch-band UWB antenna, and multiband antennas. The dual notch-band functions are obtained by using two stepped impedance stub-loaded SIRs. The reconfigurable characteristics are achieved by using two ideal switches on SIRs. The measurement and simulation results show that the proposed reconfigurable antenna has good switchable characteristics and dual notch-band functions. The designed reconfigurable antenna is suitable for future multimode wireless communications systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:52-55, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27253 Copyright © 2012 Wiley Periodicals, Inc.

Source title: Microwave and Optical Technology Letters

Series Number: Volume 55 Issue 1

DOI: 10.1002/mop.27253

Link: A reconfigurable wide slot antenna integrated with sirs for UWB/multiband communication applications

Li, Y.; Li, W.; Ye, Q.
Miniaturization of asymmetric coplanar strip-fed staircase ultrawideband antenna with reconfigurable notch band

Year: 2013

Abstract: A compact asymmetric coplanar strip-fed staircase ultrawideband (UWB) antenna with notch band reconfigurable characteristic is proposed and investigated numerically and experimentally.The reconfigurable notch bands are realized by using a spur-slot and an ideal switch. By controlling the switch at OFF and ON states, the notch bands of the proposed UWB antenna can work at 3.5 and 8.2 GHz, respectively. Numerical and experimental results show that the proposed antenna is capable of working for entire UWB application and providing the reconfigurable notch bands. © 2013 Wiley Periodicals, Inc.

Source title: Microwave and Optical Technology Letters

Series Number: Volume 55 Issue 7

DOI: 10.1002/mop.27634

Link: Miniaturization of asymmetric coplanar strip-fed staircase ultrawideband antenna with reconfigurable notch band

Li, Y.; Li, W.; Ye, Q.
A compact asymmetric coplanar strip-fed dual-band antenna for 2.4/5.8 GHz wlan applications

Year: 2013

Abstract: An asymmetric coplanar strip (ACS)-fed dual-band antenna using loaded capacitance terminations for 2.4/5.8 GHz wireless local area network applications is studied numerically and verified experimentally. The proposed antenna consists of two meandered strip radiating elements, two loaded capacitance terminations, an asymmetric ground plane, a shunt inductor, and an ACS-fed structure. Two resonance frequencies are controlled by adjusting the dimensions of the two meandered strip radiator elements and two loaded capacitance terminations. This antenna has small size of 17 × 12 mm2 including the ground plane. Simulation and measurement results show that the proposed antenna can work at dual-band frequencies and has omnidirectional radiation patterns. © 2013 Wiley Periodicals, Inc.

Source title: Microwave and Optical Technology Letters

Series Number: Volume 55 Issue 9

DOI: 10.1002/mop.27741

Link: A compact asymmetric coplanar strip-fed dual-band antenna for 2.4/5.8 GHz wlan applications

Li, Y.; Li, W.; Ye, Q.
A reconfigurable triple-notch-band antenna integrated with defected microstrip structure band-stop filter for ultra-wideband cognitive radio applications

Year: 2013

Abstract: A printed reconfigurable ultra-wideband (UWB) monopole antenna with triple narrow band-notched characteristics is proposed for cognitive radio applications in this paper. The triple narrow band-notched frequencies are obtained using a defected microstrip structure (DMS) band stop filter (BSF) embedded in the microstrip feed line and an inverted π-shaped slot etched in the rectangular radiation patch, respectively. Reconfigurable characteristics of the proposed cognitive radio antenna (CRA) are achieved by means of four ideal switches integrated on the DMS-BSF and the inverted p-shaped slot. The proposed UWB CRA can work at eight modes by controlling switches ON and OFF. Moreover, impedance bandwidth, design procedures, and radiation patterns are presented for analysis and explanation of this antenna. The designed antenna operates over the frequency band between 3.1 GHz and 14 GHz (bandwidth of 127.5%), with three notched bands from 4.2 GHz to 6.2 GHz (38.5%), 6.6 GHz to 7.0 GHz (6%), and 12.2 GHz to 14 GHz (13.7%). The antenna is successfully simulated, fabricated, and measured. The results show that it has wide impedance bandwidth, multimodes characteristics, stable gain, and omnidirectional radiation patterns. © 2013 Yingsong Li et al.

Source title: International Journal of Antennas and Propagation

Series Number: Volume 2013

DOI: 10.1155/2013/472645

Link: A reconfigurable triple-notch-band antenna integrated with defected microstrip structure band-stop filter for ultra-wideband cognitive radio applications

Li, Y.; Li, W.; Ye, Q.
A CPW-fed circular wide-slot UWB antenna with wide tunable and flexible reconfigurable dual notch bands

Year: 2013

Abstract: A coplanar waveguide (CPW)-fed circular slot antenna with wide tunable dual band-notched function and frequency reconfigurable characteristic is designed, and its performance is verified experimentally for ultra-wideband (UWB) communication applications. The dual band-notched function is achieved by using a T-shaped stepped impedance resonator (T-SIR) inserted inside the circular ring radiation patch and by etching a parallel stub loaded resonator (PSLR) in the CPW transmission line, while the wide tunable bands can be implemented by adjusting the dimensions of the T-SIR and the PSLR. The notch band reconfigurable characteristic is realized by integrating three switches into the T-SIR and the PSLR. The numerical and experimental results show that the proposed antenna has a wide bandwidth ranging from 2.7 GHz to 12 GHz with voltage standing wave ratio (VSWR) less than 2, except for the two notch bands operating at 3.8-5.9 GHz and 7.7-9.2 GHz, respectively. In addition, the proposed antenna has been optimized to a compact size and can provide omnidirectional radiation patterns, which are suitable for UWB communication applications. © 2013 Yingsong Li et al.

Source title: The Scientific World Journal

Series Number: Volume 2013

DOI: 10.1155/2013/402914

Link: A CPW-fed circular wide-slot UWB antenna with wide tunable and flexible reconfigurable dual notch bands

Li, Y.; Li, W.; Ye, Q.
Rate-compatible LDPC-RS product codes based on raptor-like LDPC codes

Year: 2013

Abstract: In this paper, we propose a novel rate-compatible LDPC-RS product code structure which combines Raptor-like LDPC codes and RS codes in a product way. While maintaining the advantages of traditional LDPC-RS product codes, such as combating different types of errors and offering various decoding solutions, the new code structure gains the feature of rate-compatibility thanks to the application of Raptor-like LDPC code as one of its component codes. To make full use of its advantages, we derive a hybrid, iterative and adaptive decoding scheme for this code structure. We show that on one hand, this decoding scheme organizes LDPC soft-decision decoding, LDPC hard-decision decoding and RS hard-decision decoding in a proper way which improves error performance as well as reduces the complexity; on the other hand, considering rate-compatibility, this scheme implements 'partial decoding' which adapts the code rate with the channel condition and further lowers the decoding complexity and system latency. This rate-compatible LDPC-RS product codes offer a potential solution for channel coding in next-generation broadcasting systems. © 2013 IEEE.

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

DOI: 10.1109/BMSB.2013.6621783

Link: Rate-compatible LDPC-RS product codes based on raptor-like LDPC codes

Li, Y.; Liu, B.; Rong, B.; Wu, Y.; Gagnon, G.; Gui, L.; Zhang, W.
Next generation cognitive cellular networks: Spectrum sharing and trading [Guest editorial]

Year: 2013

Abstract: In the past few years, fundamental research has demonstrated great potentials of cognitive radio (CR) in increasing the spectrum agility and system capacity of wireless communications systems. With the ability to detect and adapt to the surrounding environment, CR has become one of the widely recognized features for future wireless communication systems. Specifically, CR has been recommended as a key technology to solve the spectrum scarcity problem in the next generation cellar networks. For example, the IEEE 802.16h standard was recently published for the license-exempt operation of WiMAX networks by defining a set of CR capabilities. On the other hand, a lot of efforts are being made to introduce CR features into 3GPP LTE-Advanced. © 2002-2012 IEEE.

Source title: IEEE Wireless Communications

Series Number: Volume 20 Issue 2

DOI: 10.1109/MWC.2013.6507388

Link: Next generation cognitive cellular networks: Spectrum sharing and trading [Guest editorial]

Lu, K.; Rong, B.; Kota, S.; Liu, G.; Wang, X.
Bandwidth Broadening of Dual-Slot Antenna Using Substrate Integrated Waveguide (SIW)

Year: 2013

Abstract: This letter presents a dual-slot antenna etched on a substrate integrated waveguide. This antenna is designed, fabricated, and measured to operate at X-band. It uses two unequal slots in order to increase the bandwidth. The measured results show a bandwidth of 8.5%, which is twice that of the standard dual-slot antennas. Attractive features including low cost, compact size, and planar form make this antenna easy to integrate within microwave planar circuits. © 2013 IEEE.

Source title: IEEE Antennas and Wireless Propagation Letters

Series Number: Volume 12

DOI: 10.1109/LAWP.2013.2281295

Link: Bandwidth Broadening of Dual-Slot Antenna Using Substrate Integrated Waveguide (SIW)

Mbaye, M.; Hautcoeur, J.; Talbi, L.; Hettak. K.
Phase error analysis of the effect of feed movement on bandwidth performance of a broadband X-Ku band reflectarray

Year: 2013

Abstract: A new cell element is introduced for broadband reflectarray applications. The presented unit cell exhibits linear phase response which makes it a suitable candidate for broadband X-Ku band applications. This cell element consists of three concentric rectangular loops etched on a two-layer grounded substrate. The dimensions of the cell element have been optimized to achieve linear phase response in the operation band. A square offset-fed reflectarray of 40 cm × 40 cm was designed and fabricated based on this unit cell with wideband performance at X-Ku band. Considering three different feed positions, the whole reflectarray was simulated in CST and good agreement between simulated and measured results was observed. A maximum gain of 32 dBi was obtained which is equivalent to 58% aperture efficiency. Also, a remarkable value of 36%, 1.5-dB gain bandwidth was measured which is higher compared to previously reported designs in the literature. Another investigation that is carried out in this development through theory and simulation is determination of the effect of feed movement along the focal axis on the operating band of the reflectarray. It is shown for the first time that changing the feed location leads to a considerable shift in the operation bandwidth and maximum gain of the designed broadband reflectarray. Copyright © 2012 Wiley Periodicals, Inc.

Source title: International Journal of RF and Microwave Computer-Aided Engineering

Series Number: Volume 23 Issue 5

DOI: 10.1002/mmce.20685

Link: Phase error analysis of the effect of feed movement on bandwidth performance of a broadband X-Ku band reflectarray

Mohammadirad, M.; Komjani, N.; Chaharmir, M.R.; Shaker, J.; Sebak, A.R.
Cloud Transmission: System simulation and performance analysis

Year: 2013

Abstract: The Cloud Transmission (Cloud Txn) is a new paradigm of broadcasting or point-to-multipoint transmission system, designed for efficient and flexible use of the spectrum, robustness against noise, multipath and co-channel interference, and capability to provide fixed or mobile reception while using low transmission power. Besides system capability, the system should meet many other challenging issues. The main purpose of this work is to demonstrate that this proposed new system is feasible and it meets today and future needs of the broadcasting industry. © 2013 IEEE.

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

DOI: 10.1109/BMSB.2013.6621714

Link: Cloud Transmission: System simulation and performance analysis

Montalban, J.; Rong, B.; Park, S.I.; Wu, Y.; Kim, J.; Kim, H.M.; Zhang, L.; Nadeau, C.; Lafleche, S.; Angueira, P.; Velez, M.
Cloud Transmission frequency domain cancellation

Year: 2013

Abstract: Cloud Transmission (Cloud Txn) is a spectrum efficient broadcasting system, which removes the co-channel interference through the use of robust forward error correction (FEC) codes. Nevertheless, the main drawback of this approach is that the system overall data rate is reduced. As a solution, the system proposes a spectrum overlay technology to increase data throughput while maintaining the robustness. The goal of this paper is to further explain and justify the spectrum overlay and corresponding frequency domain cancellation techniques. © 2013 IEEE.

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

DOI: 10.1109/BMSB.2013.6621769

Link: Cloud Transmission frequency domain cancellation

Montalban, J.; Rong, B.; Wu, Y.; Zhang, L.; Angueira, P.; Velez, M.
Design of multichannel frequency domain statistical-based enhancement systems preserving spatial cues via spectral distances minimization

Year: 2013

Abstract: It is often very important for multichannel speech enhancement systems, such as hearing aids, to preserve spatial impressions. Usually, this is achieved by first designing a particular speech enhancement algorithm and later or separately constraining the obtained solution to respect spatial cues. Instead, we propose in this paper to conduct the entire systems design via the minimization of statistical spectral distances seen as functions of a real-valued, common gain to be applied to all channels in the frequency-domain. For various spectral distances, we show that the gain derived is expressible in terms of optimal multichannel spectral amplitude estimators (such as the multichannel Minimum Mean Squared Error Spectral Amplitude Estimator, among others). In addition, we report experimental results in complex environments (i.e., including reverberation, interfering talkers, and low signal-to-noise ratio), showing the potential of the proposed methods against recent state-of-the-art multichannel enhancement setups which preserve spatial cues as well.

Source title: Signal Processing

Series Number: Volume 93 Issue 1

DOI: 10.1016/j.sigpro.2012.06.024

Link: Design of multichannel frequency domain statistical-based enhancement systems preserving spatial cues via spectral distances minimization NOTE: A login may be required to access this site.

Mustiere, F.; Bouchard, M.; Najaf-Zadeh, H.; Pichevar, R.; Thibault, L.; Saruwatari, H.
Powering a data center network via renewable energy: A green testbed

Year: 2013

Abstract: Today's information and communications technology (ICT) services emit an increasing amount of greenhouse gases. Carbon footprint models can enable research into ICT energy efficiency and carbon reduction. The GreenStar Network (GSN) testbed is a prototype wide-area network of data centers powered by renewable energy sources. Through their work developing the GSN, the authors have researched fundamental aspects of green ICT such as virtual infrastructure, unified management of compute, network, power, and climate resources, smart power control, and a carbon assessment protocol. © 1997-2012 IEEE.

Source title: IEEE Internet Computing

Series Number: Volume 17 Issue 1

DOI: 10.1109/MIC.2012.125

Link: Powering a data center network via renewable energy: A green testbed

Nguyen, K.-K.; Cheriet, M.; Lemay, M.; Savoie, M.; Ho, B.
On capacity provisioning in datacenter networks for full bandwidth communication

Year: 2013

Abstract: Recent advances in datacenter network design have enabled full bandwidth communication based on the notion of Valiant load balancing. In this paper, we study from the link capacity viewpoint how such communication paradigm can be supported in the context of link failures, the study of which is currently absent. In particular, we target full bandwidth communication among all the servers, for all valid traffic patterns, and under k arbitrary link failures. We derive the minimum link capacity required on two typical datacenter topologies - VL2 and fat-tree. Our main finding is that given the same server scale, fat-tree requires less total link capacity than VL2 for 1 ≤ k ≤ n/4, where n denotes the port count of homogeneous switches used in fat-tree. For k > n/4, there exists a turning point from which VL2 becomes more capacity-efficient. © 2013 IEEE.

Source title: IEEE International Conference on High Performance Switching and Routing, HPSR

DOI: 10.1109/HPSR.2013.6602291

Link: On capacity provisioning in datacenter networks for full bandwidth communication

Ni, W.; Huang, C.; Wu, J.
Analytical models of flow availability in two-layer networks with dedicated path protection

Year: 2013

Abstract: Even with protection, user traffic flows can be disrupted due to network failures that are beyond the protection capability. One of the quantitative metrics to measure the service quality in such a context is availability. We study analytical models that compute availability of upper-layer flows in two-layer networks with dedicated path protection at either the upper or the lower layer. Our investigations reveal that existing analytical models significantly overestimate availability requirements on lower-layer links, and exaggerate upper-layer flow unavailability by treating correlated upper-layer failures as being independent. In contrast, our proposed model takes into account such correlations by tracing upper-layer failures to lower-layer root causes, thus greatly relaxing unnecessary high-availability requirements on lower-layer links without compromising the availability of upper-layer flows. In our simulation examples, using the existing models, up to 66.6% and 89.2% of the total flows are overestimated on their unavailability under dedicated path protection at the upper and the lower layer, respectively. Moreover, the average unavailability redundancy built into these flows is about 30% and 15% for protection at the upper and the lower layer, respectively. Furthermore, we compare flow availability under the two protection schemes, and show that given the same initial unprotected network states, protection at the lower layer enjoys lower average flow unavailability than protection at the upper layer. © 2012 Elsevier B.V.

Source title: Optical Switching and Networking

Series Number: Volume 10 Issue 1

DOI: 10.1016/j.osn.2012.07.005

Link: Analytical models of flow availability in two-layer networks with dedicated path protection NOTE: A login may be required to access this site.

Ni, W.; Wu, J.; Huang, C.; Savoie, M.
VeMAC: A TDMA-based MAC protocol for reliable broadcast in VANETs

Year: 2013

Abstract: The need of a medium access control (MAC) protocol for an efficient broadcast service is of great importance to support the high-priority safety applications in vehicular ad hoc networks (VANETs). This paper introduces VeMAC, a novel multichannel TDMA MAC protocol proposed specifically for a VANET scenario. The VeMAC supports efficient one-hop and multihop broadcast services on the control channel by using implicit acknowledgments and eliminating the hidden terminal problem. The protocol reduces transmission collisions due to node mobility on the control channel by assigning disjoint sets of time slots to vehicles moving in opposite directions and to road side units. Analysis and simulation results in highway and city scenarios are presented to evaluate the performance of VeMAC and compare it with ADHOC MAC, an existing TDMA MAC protocol for VANETs. It is shown that, due to its ability to decrease the rate of transmission collisions, the VeMAC protocol can provide significantly higher throughput on the control channel than ADHOC MAC. © 2002-2012 IEEE.

Source title: IEEE Transactions on Mobile Computing

Series Number: Volume 12 Issue 9

DOI: 10.1109/TMC.2012.142

Link: VeMAC: A TDMA-based MAC protocol for reliable broadcast in VANETs

Omar, H.A.; Zhuang, W.; Li, L.
A newly designed quarter-rate QC-LDPC code for the cloud transmission system

Year: 2013

Abstract: In this brief, we propose a newly designed quarter-rate quasi-cyclic low density parity check (LDPC) code for the cloud transmission system. The cloud transmission system requires a near Shannon limit low-rate coding for the next generation terrestrial digital television system. The proposed LDPC code is optimized for R = 1/4. At the code length of 64 K, it is only 0.6 dB away from Shannon limit. Copyright © 1963-12012 IEEE.

Source title: IEEE Transactions on Broadcasting

Series Number: Volume 59 Issue 1

DOI: 10.1109/TBC.2012.2226673

Link: A newly designed quarter-rate QC-LDPC code for the cloud transmission system

Park, S.I.; Kim, H.M.; Wu, Y.; Kim, J.
Robust synchronization for the OFDM-based cloud transmission system

Year: 2013

Abstract: In this paper, we propose a frame structure and robust synchronization to realize the cloud transmission (Cloud Txn) system. The proposed frame structure is based on orthogonal frequency division multiplexing (OFDM) for the Cloud Txn system. Also, we study the robust synchronization suitable for the proposed OFDM-based frame structure. Simulation results show that the proposed frame structure and synchronization are feasible for OFDM-based Cloud Txn system under the negative SNR environment. © 2013 IEEE.

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

DOI: 10.1109/BMSB.2013.6621774

Link: Robust synchronization for the OFDM-based cloud transmission system

Park, S.I.; Kim, H.M.; Wu, Y.; Zhang, L.; Hur, N.; Kim J.
Backward compatible UHDTV transmission based on ADT system for the ATSC terrestrial DTV broadcasting

Year: 2013

Abstract: This paper proposes a backward compatible UHDTV transmission based on augmented data transmission (ADT) system for the ATSC terrestrial DTV broadcasting. The proposed system provides MPEG-2 DTV signal with a rate of 19.3 Mbps and HEVC-base ADT signal with a rate of about 7 Mbps. If we combine MPEG-2 DTV signal and HEVC-base ADT signal properly, we can provide 4K UHD video service as well as backward compatible HD video service simultaneously. © 2013 IEEE.

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

DOI: 10.1109/BMSB.2013.6621678

Link: Backward compatible UHDTV transmission based on ADT system for the ATSC terrestrial DTV broadcasting

Park, S.I.; Lee, G.; Wu, Y.; Kim, H.M.; Hur, N.; Chung, J.-H.; Kim, J.
Quarter-rate LDPC code and its truncated performance for the cloud transmission

Year: 2013

Abstract: This paper explains the structure of a newly designed quarter-rate low density parity check (LDPC) code for the cloud transmission system, and presents its truncated performance under additive white Gaussian noise (AWGN) channel. Since new quarter-rate LDPC code has fountain code's property, at the receiver, it can be decoded with truncated codeword for power saving and less latency under high signal to noise ratio (SNR) regions. By computer simulation, the truncated LDPC code shows the same or worse performance compared with the dedicated DVB-T2/S2 LDPC code. © 2013 IEEE.

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

DOI: 10.1109/BMSB.2013.6621773

Link: Quarter-rate LDPC code and its truncated performance for the cloud transmission

Park, S.I.; Wu, Y.; Kim, H.M.; Zhang, L.; Chung, J.-H.; Hur, N.; Kim, J.
Probabilistic forecasting of ionospheric scintillation and GNSS receiver signal tracking performance at high latitudes

Year: 2013

Abstract: At high latitudes, phase scintillation occurs predominantly on the dayside in the ionospheric footprint of the magnetospheric cusp, and in the nightside auroral oval. A new technique of probabilistic forecasting of phase scintillation occurrence relative to the arrival time of high-speed solar wind from coronal holes and interplanetary coronal mass ejections has recently been proposed [Prikryl et al. 2012]. Cumulative probability distribution functions for the phase-scintillation occurrence that are obtained can be specified for low (below-median) and high (above-median) values of various solar wind plasma parameters. Recent advances in modeling of high-speed solar wind and coronal mass ejections, combined with the probabilistic forecasting of scintillation, will lead to improved operational space weather forecasting applications. Scintillation forecasting and mitigation techniques need to be developed to avoid potential costly failures of technology-based Global Navigation Satellite Systems in the near future, in particular during the upcoming solar maximum. The Global Navigation Satellite Systems receiver-tracking performance during severe scintillation conditions can be assessed by the analysis of receiver phase-locked-loop jitter. Tracking jitter maps [Sreeja et al. 2011] offers a potentially useful tool to provide users with expected tracking conditions, if based on scintillation predictions as proposed above. Scintillation indices are obtained from L1 GPS data collected with the Canadian High Arctic Ionospheric Network. Combined with high rate amplitude and phase data, they can be used as input to receiver tracking models to develop scintillation mitigation techniques. © 2013 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved.

Source title: Annals of Geophysics

Series Number: Volume 56 Issue 2

DOI: 10.4401/ag-6219

Link: Probabilistic forecasting of ionospheric scintillation and GNSS receiver signal tracking performance at high latitudes

Prikryl, P.; Sreeja, V.; Aquino, M.; Jayachandran, P.T.
GPS phase scintillation and proxy index at high latitudes during a moderate geomagnetic storm

Year: 2013

Abstract: The amplitude and phase scintillation indices are customarily obtained by specialised GPS Ionospheric Scintillation and TEC Monitors (GISTMs) from L1 signal recorded at the rate of 50 Hz. The scintillation indices S4 and σΦ are stored in real time from an array of high-rate scintillation receivers of the Canadian High Arctic Ionospheric Network (CHAIN). Ionospheric phase scintillation was observed at high latitudes during a moderate geomagnetic storm (Dst= 61 nT) that was caused by a moderate solar wind plasma stream compounded with the impact of two coronal mass ejections. The most intense phase scintillation (sΦ ~ 1 rad) occurred in the cusp and the polar cap where it was co-located with a strong ionospheric convection, an extended tongue of ionisation and dense polar cap patches that were observed with ionosondes and HF radars. At sub-auroral latitudes, a sub-auroral polarisation stream that was observed by mid-latitude radars was associated with weak scintillation (defined arbitrarily as σΦ < 0.5 rad). In the auroral zone, moderate scintillation coincided with auroral breakups observed by an all-sky imager, a riometer and a magnetometer in Yellowknife. To overcome the limited geographic coverage by GISTMs other GNSS data sampled at 1 Hz can be used to obtain scintillation proxy indices. In this study, a phase scintillation proxy index (delta phase rate, DPR) is obtained from 1-Hz data from CHAIN and other GPS receivers. The 50-Hz and 1-Hz phase scintillation indices are correlated. The percentage occurrences of σΦ > 0.1 rad and DPR > 2 mm s-1, both mapped as a function of magnetic latitude and magnetic local time, are very similar. © 2013 Author(s).

Source title: Annales Geophysicae

Series Number: Volume 31 Issue 5

DOI: 10.5194/angeo-31-805-2013

Link: GPS phase scintillation and proxy index at high latitudes during a moderate geomagnetic storm

Prikryl, P.; Ghoddousi-Fard, R.; Kunduri, B.S.R.; Thomas, E.G.; Coster, A.J.; Jayachandran, P.T.; Spanswick, E.; Danskin, D.W.
An interhemispheric comparison of GPS phase scintillation with auroral emission observed at the South Pole and from the DMSP satellite

Year: 2013

Abstract: The global positioning system (GPS) phase scintillation caused by high-latitude ionospheric irregularities during an intense high-speed stream (HSS) of the solar wind from April 29 to May 5, 2011, was observed using arrays of GPS ionospheric scintillation and total electron content monitors in the Arctic and Antarctica. The one-minute phase-scintillation index derived from the data sampled at 50 Hz was complemented by a proxy index (delta phase rate) obtained from 1-Hz GPS data. The scintillation occurrence coincided with the aurora borealis and aurora australis observed by an all-sky imager at the South Pole, and by special sensor ultraviolet scanning imagers on board satellites of the Defense Meteorological Satellites Program. The South Pole (SP) station is approximately conjugate with two Canadian High Arctic Ionospheric Network stations on Baffin Island, Canada, which provided the opportunity to study magnetic conjugacy of scintillation with support of riometers and magnetometers. The GPS ionospheric pierce points were mapped at their actual or conjugate locations, along with the auroral emission over the South Pole, assuming an altitude of 120 km. As the aurora brightened and/or drifted across the field of view of the all-sky imager, sequences of scintillation events were observed that indicated conjugate auroras as a locator of simultaneous or delayed bipolar scintillation events. In spite of the greater scintillation intensity in the auroral oval, where phase scintillation sometimes exceeded 1 radian during the auroral break-up and substorms, the percentage occurrence of moderate scintillation was highest in the cusp. Interhemispheric comparisons of bipolar scintillation maps show that the scintillation occurrence is significantly higher in the southern cusp and polar cap. © 2013 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved.

Source title: Annals of Geophysics

Series Number: Volume 56 Issue 2

DOI: 10.4401/ag-6227

Link: An interhemispheric comparison of GPS phase scintillation with auroral emission observed at the South Pole and from the DMSP satellite

Prikryl, P.; Zhang, Y.; Ebihara, Y.; Ghoddousi-Fard, R.; Jayachandran, P.T.; Kinrade, J.; Mitchell, C.N.; Weatherwax, A.T.; Bust, G.; Cilliers, P.J.; Spogli, L.; Alfonsi, L.; Romano, V.; Ning, B.; Li, G.; Jarvis, M.J.; Danskin, D.W.; Spanswick, E.; Donovan, E.; Terkildsen, M.
Multi-layer iterative LDPC decoding for broadband wireless access networks: A recursive shortening algorithm

Year: 2013

Abstract: This paper presents a novel multi-layer iterative decoding scheme using deterministic bits to lower the decoding threshold of LDPC codes in wireless 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. In particular, our multi-layer scheme integrates deterministic bit identification into LDPC decoding process. This integration is able to make significant performance improvement if adequate deterministic bits are discovered. We find that the length of deterministic bits may vary from time to time, and the exploring of deterministic bits is associated to a series of shortened parity matrices during the decoding iterations. Accordingly, we develop a recursive LDPC shortening algorithm to match the dynamic length and facilitate the iterative identification of deterministic bits. Simulation results show that our proposed scheme can achieve considerable gain in today's most popular broadband wireless access networks such as WiMAX. © 2002-2012 IEEE.

Source title: IEEE Transactions on Wireless Communications

Series Number: Volume 12 Issue 3

DOI: 10.1109/TWC.2013.011713.120914

Link: Multi-layer iterative LDPC decoding for broadband wireless access networks: A recursive shortening algorithm

Rong, B.; Wu, Y.; Gagnon, G.
A novel artificial magnetic material based on a CPW series-connected resonator and its implementation in original applications

Year: 2013

Abstract: In this paper, a new class of artificial magnetic materials (AMMs) based on a modified uniplanar series resonator folded to form a close-loop inclusion which contains a distributed capacitance and inductance is introduced. Many advantages of the proposed design over conventional split ring resonators are discussed. The resonant frequency at which a banstop region occurs due to the presence of negative effective permeability in the dielectric slab of the host transmission line near the resonance is calculated and compared with simulated results. Two prototype microwave devices are provided to illustrate the potentiality of the proposed inclusion; The first design represents a dual-band bandstop filter with a designed center band frequencies at 1.8 GHz and 2.4 GHz, the lumped element model of this filter contains four series-connected parallel LC resonators which are implemented using our high Q-factor AMMs patterned on the backside of a CPW transmission line. The second device is a miniaturized hybrid branch line coupler operates at 2.4 GHz; based on a special loading technique that increases the electric length of transmission lines by patterning the ground plane under the conductor trace in microstrip lines with the complementary, dual-behavior, configuration of AMMs, a miniaturization factor up to 18.41 % is achieved compared to the conventional couplers. For both design examples the simulated responses show their high performance which validates our work. © 2013 EurAAP.

Source title: 2013 7th European Conference on Antennas and Propagation, EuCAP 2013

DOI: N/A

Link: A novel artificial magnetic material based on a CPW series-connected resonator and its implementation in original applications

Safia, O.A.; Talbi, L.; Hettak, K.
Derivation of accurate equivalent circuit models for multilayer periodic structures

Year: 2013

Abstract: This paper presents a procedure based on using the results of full-wave simulation of a multilayer filter to extract poles and zeros of admittance functions of a pi-network which represents that same structure. The functional form of the admittance is then used to arrive at a more accurate estimate of the equivalent circuit of the multilayer filter. Admittance values calculated through full-wave analysis are compared to the same results from a pole-zero extraction method in order to verify the validity of the latter. © 2013 IEEE.

Source title: Proceedings of the 2013 International Conference on Electromagnetics in Advanced Applications, ICEAA 2013

DOI: 10.1109/ICEAA.2013.6632237

Link: Derivation of accurate equivalent circuit models for multilayer periodic structures

Shaker, J.; Chaharmir, M.R.
Disparity remapping to ameliorate visual comfort of stereoscopic video

Year: 2013

Abstract: The great success of the three-dimensional (3D) digital cinema industry has opened up a new era of 3D content services. While we have witnessed a rapid surge of stereoscopic 3D services, the issue of viewing safety remains a possible obstacle to the widespread deployment of such services. In this paper, we propose a novel disparity remapping method to reduce the visual discomfort induced by fast change in disparity. The proposed remapping approach selectively adjusts the disparities of the discomfort regions where the fast change in disparity occurs. To this purpose, the proposed approach detects visual importance regions in a stereoscopic 3D video, which may have dominant influence on visual comfort in video frames, and then locally adjust the disparity by taking into account the disparity changes in the visual importance regions. The experimental results demonstrate that the proposed approach to adjust local problematic regions can improve visual comfort while preserving naturalness of the scene. © 2013 SPIE-IS&T.

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

DOI: 10.1117/12.2002989

Link: Disparity remapping to ameliorate visual comfort of stereoscopic video

Sohn, H.; Jung, Y.J.; Lee, S.-I.; Speranza, F.; Ro, Y.M.
Covert OFDM transmission using CDD based frequency selective channel

Year: 2013

Abstract: Orthogonal Frequency Division Multiplexing (OFDM) has become an increasingly common technique in communication systems and raised tremendous security concerns recently. This paper proposes to achieve covert OFDM transmission with cyclic delay diversity (CDD) featured multiple input multiple output (MIMO) technology. Particularly, our physical layer security scheme takes the advantage of CDD formed frequency selective channel and addresses uneven comb pilots to confuse unauthorized receivers and benefit authorized receivers. Numerical results justify that, with our design, the CDD paradigm can efficiently safeguard OFDM system, and the performance can be further optimized by fine tuning channel estimation for authorized users. © 2013 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2013.6831154

Link: Covert OFDM transmission using CDD based frequency selective channel

Sun, S.; Rong, B.; Ju, Y.
Turbo code using adaptive puncturing for transform domain Wyner-Ziv video coding

Year: 2013

Abstract: In most DVC architectures presented in the literature, the puncturing mechanism operates according to a periodic pattern that spreads uniformly the turbo generated parity bits and discards all the systematic bits. These latter are replaced by the receiver side information (SI) during the turbo decoding process. The side information is generated by a block based motion interpolation algorithm that can, furthermore, predict whether or not each block is well interpolated. Thus, instead of uniformly dispersing the parity bits over the whole turbo code trellis, they can be directed to the most corrupted regions. If the side information displays regions that appear to be even more highly corrupted, systematic bits can likewise be guided adaptively towards these regions. In this paper, an adaptive puncturing scheme is proposed. A classification of the corrupted parts of each DCT band of the interpolated frame is performed and then an adaptive puncturing mechanism is employed for a more efficient parity and systematic bits repartition. Simulation results show that the adaptive puncturing scheme can provide as much as 20% of Wyner-Ziv bitrate reduction: this is reflected by a PSNR vs bit rate performance improvement of up to 1.8 dB. © 2013 IEEE.

Source title: 2013 13th Canadian Workshop on Information Theory, CWIT 2013

DOI: 10.1109/CWIT.2013.6621595

Link: Turbo code using adaptive puncturing for transform domain Wyner-Ziv video coding

Taieb, M.H.; Chouinard, J.-Y.; Wang, D.
Low complexity rate estimators for low latency Wyner-Ziv video decoders

Year: 2013

Abstract: Distributed video coding is a video paradigm where most of the computational complexity can be transferred from video encoders to the decoders. This allows for video sequences transmission involving inexpensive encoders and powerful centralized decoders. Unfortunately, due to the typically numerous feedback requests and needed decoders run cycles, this often leads to unacceptably long decoding latencies. One approach to addressing the latency problem consists in estimating an initial number of parity bit chunks (INC) that are then sent at once to reduce the number of decoders run cycles. A practical implementation challenge is to properly estimate as accurately as possible the INC, that is, without neither underestimation nor overestimation. This paper proposes two INC estimation techniques based on the temporal correlation between successive Wyner-Ziv frames and on the correlation between the different bit-planes.

Source title: Engineering Letters

Series Number: Volume 21 Issue 1

DOI: N/A

Link: Low complexity rate estimators for low latency Wyner-Ziv video decoders NOTE: A login may be required to access this site.

Taieb, M.H.; Chouinard, J.-Y.; Wang, D.
Pure asynchronous neighbor discovery algorithms in ad hoc networks using directional antennas

Year: 2013

Abstract: Asynchronous system provides great performance improvement for wireless ad hoc networks, such as anti-jamming, collision reduction and device simplification. Nevertheless, new media access and routing protocols are required to assist the asynchronous system, e.g., a neighbor discovery algorithm, which is the first step in the initialization of wireless ad hoc networks. In the past few years, a number of algorithms have been proposed for neighbor discovery. However, most of them only consider synchronous system and cannot work efficiently in asynchronous system. In this paper, firstly, we propose an analytical model for an 1-way asynchronous system in wireless ad hoc networks with directional antennas. Then, we compare the time-slot consumption in asynchronous system to complete the neighbor discovery process with that in synchronous system. Finally, in order to improve the performance of the neighbor discovery process, we extend the 1-way asynchronous discovery algorithms to a 2-way asynchronous discovery algorithm. To the best of our knowledge, this is the first practical analytical model of 2-way asynchronous neighbor discovery algorithm with directional antennas. © 2013 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2013.6831120

Link: Pure asynchronous neighbor discovery algorithms in ad hoc networks using directional antennas

Tian, F.; Hu, R.Q.; Qian, Y.; Rong, B.; Liu, B.; Gui, L.
Channel models for aeronautical and low elevation radio links

Year: 2013

Abstract: The problematic of the calculation of the tropospheric effects on low elevation links has become important for the last few years. The limitations of the existing models are summarized and new models developed during COST0802 Action are presented. The necessity of making measurement campaigns for testing the models is stressed.

Source title: 7th European Conference on Antennas and Propagation, EuCAP 2013

DOI: N/A

Link: Channel models for aeronautical and low elevation radio links

Vanhoenacker-Janvier, D.; Bouchard, P.; Braten, L.E.; Fabbro, V., Kourogiorgas C., Rogers D.V.
2D-to-3D Video Conversion: Overview and Perspectives

Year: 2013

Abstract: This chapter focuses on the rapid development of 2D-to-3D video conversion techniques that allow the generation of stereoscopic video from a standard monoscopic video source. It explores the different methods currently used to define the depth structure of the scene for 2D-to-3D conversion of video content. The chapter classifies the methods into two main categories: 1) Depth creation methods; and 2) Depth recovery methods. The 2D-to-3D video conversion is related to the generation of the second video stream for stereoscopic visualization. Ideally, 2D-to-3D conversion should produce content that has no picture artifacts, that has good depth, and that respects the artistic composition of the original video. It is clear that the research on 2D-to- 3D video conversion is progressing at a very rapid pace and with very encouraging results. Such progress is simply the consequence of the increasing attention that this research has been receiving from both industry and academia.

Source title: Emerging Technologies for 3D Video: Creation, Coding, Transmission and Rendering

Series Number: Chapter 6

DOI: 10.1002/9781118583593.ch3

Link: 2D-to-3D Video Conversion: Overview and Perspectives

Vazquez, C.; Zhang, L.; Speranza, F.; Plath, N.; Knorr, S.
Wideband high gain 1-D EBG resonator antenna

Year: 2013

Abstract: This paper describes a technique to enhance the radiation bandwidth of the 1-D EBG resonator antenna. By adding one slab with a properly chosen dielectric constant underneath the other one, the 3dB gain bandwidth of the antenna is considerably increased. The proposed method is analyzed based on a transmission-line model and verified by simulations. It is shown that the antenna designed for verification achieves a 30% half gain bandwidth through 13.7GHz to 18.6GHz with a maximum gain of 14.8dBi, and also possesses a 34% impedance bandwidth for the voltage standing wave ratio less than 2 through 13.4GHz to 18.8GHz that covers the whole radiation bandwidth, as well as very low side lobes and cross-polarizations. © 2013 IEEE.

Source title: 2013 IEEE International Wireless Symposium, IWS 2013

DOI: 10.1109/IEEE-IWS.2013.6616781

Link: Wideband high gain 1-D EBG resonator antenna

Wang, N.; Talbi, L.; Zeng, Q.; Xu, J.
Broadband EBG resonator antenna using a combination of different dielectric substrates

Year: 2013

Abstract: A novel design of an electromagnetic band gap (EBG) resonator antenna with a wide gain bandwidth at Ku band is presented. The bandwidth enhancement of the antenna is attributed to the positive reflection phase gradient of the EBG structure, which is generated by the combination of two dielectric substrates with different dielectric constants and thicknesses. The calculated results indicate that the antenna possesses a relative 3dB gain bandwidth of 26%, from 13.6GHz to 17.7GHz, with a peak gain of 15dBi, which can well cover the whole impedance bandwidth for the reflection coefficient (S11) less than -10dB, from 13.9GHz to 17.7GHz. The design method developed here is significantly effective, and can be easily adopted for antenna designs at other frequencies. © 2013 IEEE.

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

DOI: 10.1109/APS.2013.6711106

Link: Broadband EBG resonator antenna using a combination of different dielectric substrates

Wang, N.; Xu, J.; Zeng, Q.
Received signal strength-based emitter geolocation using an iterative maximum likelihood approach

Year: 2013

Abstract: Batch-mode maximum likelihood (ML) received signal strength (RSS) emitter geolocation algorithms produce location estimates from a block of data collected over an observation period using either a single sensor or collected at one time instant by multiple spatially dispersed sensors. Due to practical constraints such as processor speed, memory for data storage, time for data transfer and communications bandwidth, batch-mode algorithms can only be implemented in real-time for small data sets. This paper presents an iterative formulation of the likelihood function for the ML RSS geolocation algorithm for real-time implementation with large data sets. Simulation and experimental results are included to validate the proposed formulation. © 2013 IEEE.

Source title: Proceedings - IEEE Military Communications Conference MILCOM

DOI: 10.1109/MILCOM.2013.21

Link: Received signal strength-based emitter geolocation using an iterative maximum likelihood approach

Wang, S.; Jackson, B.R.; Rajan, S.; Patenaude, F.
A wideband high-gain stacked cylindrical dielectric resonator antenna

Year: 2013

Abstract: A new wideband and high-gain dielectric resonator antenna (DRA) is proposed. Three cylindrical dielectric resonators (DRs) with different materials and different sizes and a metallic cylinder are designed to obtain a wideband bandwidth and a high gain. The stacked structure provides a wideband bandwidth, and the cavity formed by the metallic cylinder provides a high gain. The measured results demonstrate that the proposed DRA has a wide bandwidth from 5.4 to 7.0 GHz with VSWR less than two and a gain around 11 dBi, covering the frequency range of 26%. The experimental and numerical results are discussed and compared with each other, showing a good agreement between them. © 2010 EMW Publishing. All Rights Reserved.

Source title: Progress in Electromagnetics Research Letters

Series Number: Volume 43

DOI: 10.2528/PIERL13101006

Link: A wideband high-gain stacked cylindrical dielectric resonator antenna

Wang, Y.; Denidni, T.A.; Zeng, Q.; Wei, G.
Ultra-wideband planar monopole integrated with cylindrical dielectric resonator antenna

Year: 2013

Abstract: An ultra-wideband (UWB) planar monopole antenna integrated with a narrow-band (NB) cylindrical dielectric resonator antenna (DRA) is presented. The proposed antenna consists of a UWB monopole excited by a coplanar waveguide (CPW) and a DRA excited by a slot which displays a NB characteristic. Mode HEM11Δ is excited in the NB antenna. The UWB and NB antenna provide a 2:1 voltage standing wave ratio (VSWR) bandwidth for 3.05 - 13.5 GHz and 5.1 - 5.8 GHz, respectively, with the same polarization and reasonable isolation (better than -10 dB ) between the two ports. This is a promising candidate for applications of cognitive radio, where a UWB antenna is for spectrum sensing and a NB antenna for communication operation. © 2013 IEEE.

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

DOI: 10.1109/APS.2013.6711507

Link: Ultra-wideband planar monopole integrated with cylindrical dielectric resonator antenna

Wang, Y.; Wei, G.; Denidni, T.A.; Zeng, Q.
Integrated ultra-wideband/narrow band dielectric resonator antenna

Year: 2013

Abstract: An ultra-wideband (UWB) rectangular dielectric resonator antenna (DRA) integrated with a narrow-band (NB) DRA is presented. The proposed antenna consists of a UWB DRA excited by a planar monopole and a DRA excited by a slot which displays NB characteristic. The UWB and NB antenna provides a 2:1 voltage standing wave ratio (VSWR) bandwidth for 2.5 - 11 GHz and 5.1 - 5.5 GHz, respectively, with the same polarization and a reasonable isolation (better than -10 dB) between the two ports. Moreover, the NB antenna can operate in 6.8 - 7.3 GHz or 3.75 - 3.88 GHz by little modification. This is a promising candidate for applications of cognitive radio, where a UWB antenna is for spectrum sensing and a NB antenna for communication operation. To improve the isolation between the two ports, several arrangements are investigated. © 2013 IEEE.

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

DOI: 10.1109/APS.2013.6711505

Link: Integrated ultra-wideband/narrow band dielectric resonator antenna

Wang, Y.; Wei, G.; Zeng, Q.; Denidni, T.A.
Design of high gain, broadband cylindrical dielectric resonator antenna

Year: 2013

Abstract: A new high-gain cylindrical dielectric resonator antenna (DRA) with a large bandwidth is proposed. A cylindrical dielectric resonator, an intermediate layer and a metallic cylinder are used to obtain a large bandwidth and a high gain. The intermediate layer structure can suppress surface wave propagation, which results in a gain improvement, and the cavity formed by the metallic cylinder provides a further higher gain. The measured results demonstrate that the proposed DRA achieves a large bandwidth of 23% from 5.4 to 6.8 GHz with a voltage standing wave ratio of < 2 and a high gain of around 11 dBi. © The Institution of Engineering and Technology 2013.

Source title: Electronics Letters

Series Number: Volume 49 Issue 24

DOI: 10.1049/el.2013.2741

Link: Design of high gain, broadband cylindrical dielectric resonator antenna

Wang, Y.-F.; Denidni, T.A.; Zeng, Q.-S.; Wei, G.
Integrated ultra-wideband plannar monopole with cylindrical dielectric resonator antennas

Year: 2013

Abstract: An ultra-wideband (UWB) planar monopole antenna integrated with a narrow-band (NB) cylindrical dielectric resonator antenna (DRA) is presented. The proposed antenna consists of a UWB monopole excited by a coplanar waveguide (CPW) transmission line, acting as a ground for a DRA excited by a slot. The mode HEM11Δ is excited in the NB DRA. To validate the concept of integration, an antenna is fabricated and measured. The measured results demonstrate that the UWB antenna provides a 2:1 voltage standing wave ratio (VSWR) bandwidth for 3.05-11 GHz, integrated with a dual-band NB antenna. Moreover, the two ports have the same polarization and a reasonable isolation (less than -10 dB) between each other. This is a promising candidate for applications in cognitive radio, where the UWB antenna can be used for spectrum sensing and the NB antenna for communication operation.

Source title: Progress In Electromagnetics Research C

Series Number: Volume 44

DOI: 10.2528/PIERC13070902

Link: Integrated ultra-wideband plannar monopole with cylindrical dielectric resonator antennas

Wang, Y.-F.; Liu, S.; Denidni, T.A.; Zeng, Q.-S.; Wei, G.
Impacts of surface waves on performance of an EBG resonator antenna

Year: 2013

Abstract: This paper presents the impacts of the surface waves induced by the feeding microstrip patch antenna on the performance of EBG resonator antennas. It is found that the surface waves narrow down the radiation bandwidth, widen the half radiation beamwidth in the E-plane, leading to a considerable decrease in the directivity, which should be carefully treated and abstained in the design process. © 2013 IEEE.

Source title: 2013 IEEE International Wireless Symposium, IWS 2013

DOI: 10.1109/IEEE-IWS.2013.6616799

Link: Impacts of surface waves on performance of an EBG resonator antenna

Wang,N.; Talbi, L.; Zeng, Q.; Xu, J.
Security enhancement for mobile ad hoc networks routing with OLSRv2

Year: 2013

Abstract: Some features of Mobile Ad hoc Networks (MANETs), including dynamic membership, topology, and open wireless medium, introduce a variety of security risks. Malicious nodes can drop or modify packets that are received from other nodes. These malicious activities may seriously affect the availability of services in MANETs. Therefore, secure routing in MANETs has emerged as an important MANET research area. In this paper, we propose a scheme that enhances the security of Optimal Link State Routing version 2 (OLSRv2) in MANETs based on trust. In the proposed scheme, more accurate trust can be obtained by considering different types of packets and other important factors that may cause dropping packets in friendly nodes, such as buffer overflows and unreliable wireless connections. Simulation results are presented to demonstrate the effectiveness of the proposed scheme. © 2013 SPIE.

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

Series Number: Volume 8755

DOI: 10.1117/12.2015438

Link: Security enhancement for mobile ad hoc networks routing with OLSRv2

Wei, Z.; Tang, H.; Yu, R.F.; Wang, M.
Limits on estimating autocorrelation matrices from mobile MIMO measurements

Year: 2013

Abstract: On mobile radio links, data samples collected at successive time intervals and at closely spaced frequencies are correlated, so long data records are required to acquire sufficient independent samples for analysis. Statistical analysis of long data records is not reliable because the channel statistics remain wide-sense stationary only over short distances. This is a particular concern for MIMO systems when full autocorrelation matrices may be required for channel modelling or characterisation. MIMO channel responses from mobile measurements in an urban microcell have been used to investigate the limits on estimating autocorrelation matrices, and these are compared to those predicted by commonly used channel models. © 2013 Tricia J. Willink.

Source title: International Journal of Antennas and Propagation

Series Number: Volume 2013

DOI: 10.1155/2013/345908

Link: Limits on estimating autocorrelation matrices from mobile MIMO measurements

Willink, T.J.
A belief-based approach to spectrum occupancy mapping

Year: 2013

Abstract: Maintaining a map of signal power levels is one approach to dynamic spectrum management, but generating it in a complex environment with unknown emitters using sensor measurements is challenging. Precise representation of signal levels using sparse sensors is not feasible in realistic conditions where measurements may be inaccurate and the propagation conditions are uncertain. The goal is to use sensor power measurements to identify regions where the signal level exceeds, or falls below, a given threshold, and to provide a level of confidence in those determinations. In this work, a belief-based method using Dempster-Shafer analysis is developed, which can accommodate uncertainties due to the propagation conditions and sensor inaccuracies and combines evidence from different sensors to give a belief value for each state. The method is illustrated first for a simplistic, flat-earth model, then the impacts of parameter uncertainties, shadowing and sensor errors are incorporated. A real operating environment is emulated using a propagation prediction program, and it is demonstrated that the new approach is able to provide useful input to the spectrum management function and enables a sophisticated interpretation to support context-specific decision-making. © 2013 Willink.

Source title: Eurasip Journal on Wireless Communications and Networking

Series Number: Volume 2013 Issue 1

DOI: 10.1186/1687-1499-2013-112

Link: A belief-based approach to spectrum occupancy mapping

Willink, T.J.
Measurement-based analysis of cross-layer adaptation for MIMO in mobile urban environments

Year: 2013

Abstract: The performance of mobile multiple-input-multiple-output (MIMO) systems is determined both by the instantaneous channel characteristics and by the rate of change of those characteristics. The local environment and operating frequency affect the spatial channel response, which impacts the ability of the system to sustain data throughput, while the dynamics of the channel response impact the accuracy of the available channel state information, limiting the supportable packet length. Measured MIMO data from two frequencies in the UHF band are characterised and used to investigate the dependence of system performance on the changing spatial channel responses. It is demonstrated that to maximise average throughput, taking into account retransmissions because of packet failures, a trade-off is required among the data rate, training overhead and packet length, which depends on both the operating frequency and the local environment. This work emphasizes the importance both of adaptation in MIMO communication systems and of considering realistic channel conditions in their design and evaluation. © Crown Copyright 2013.

Source title: IET Communications

Series Number: Volume 7 Issue 8

DOI: 10.1049/iet-com.2012.0752

Link: Measurement-based analysis of cross-layer adaptation for MIMO in mobile urban environments

Willink, T.J.; Colman, G.W.K.
Novel robust transmitter identification technique for digital television signals

Year: 2013

Abstract: The transmitter identification (Tx-ID) technique has been addressed in the modern ATSC digital television standards. Kasami sequences are adopted as the Tx-ID sequences due to the favorable code capacity. However, the conventional cross-correlation based Tx-ID technique cannot combat the realistic multipath channel impairment. Therefore, in this paper, we propose a new least-square Tx-ID approach, which is demonstrated to be very robust when the multipath channels are encountered. Besides, we also establish the new Hessian analysis to derive the constraint of the injection level. Finally, we devise a fast Tx-ID scheme when the channel length is set to be equal to the Tx-ID sequence length. © 2013 IEEE.

Source title: GLOBECOM - IEEE Global Telecommunications Conference

DOI: 10.1109/GLOCOM.2013.6831579

Link: Novel robust transmitter identification technique for digital television signals

Wu, H.-C.; Wu, Y.
Telecommunication Systems – Guest Editorial

Year: 2013

Abstract: [No abstract available]

Source title: Telecommunication Systems

Series Number: Volume 54 Issue 2

DOI: 10.1007/s11235-013-9724-z

Link: Telecommunication Systems – Guest Editorial

Wu, J.; Wosinska, L.; Jin, Y.; Araki, S.
Advances in optical networks control and management

Year: 2013

Abstract: [No abstract available]

Source title: Optical Switching and Networking

Series Number: Volume 10 Issue 1

DOI: 10.1016/j.osn.2012.08.003

Link: Advances in optical networks control and management NOTE: A login may be required to access this site.

Wu, J.; Wosinska, L.; Shen, G.; Spadaro, S.
Lightpath scheduling and routing for green data centres

Year: 2013

Abstract: Optical networking technologies enable data centres to be located near sources of green energy (i.e., renewable energy). Since some green energy sources are intermittent and are not always available, we need to dynamically connect distribution networks to the green energy powered data centres. On the other hand, the availability of green energy is reasonably predictable, and we are thus able to schedule connectivity to data centres in advance. We propose a WDM network planning model, which allows lightpaths to slide within their desired timing windows with no penalty on the optimization objective, and to slide beyond their desired timing windows with a deteriorating "green-level". Our simulation results show the tradeoffs between the consumption of brown energy (i.e., energy generated by carbon-intensive means), the capability of providing required connectivity to data centres, network resource utilization, and overall operation objective. © 2011 Her Majesty the Queen in Right of Canada.

Source title: Telecommunication Systems

Series Number: Volume 52 Issue 2

DOI: 10.1007/s11235-011-9644-8

Link: Lightpath scheduling and routing for green data centres

Wu, J.; Zhang, J.Y.; Savoie, M.
A proof of wavelength conversion not improving Lagrangian bounds of the sliding scheduled RWA problem

Year: 2013

Abstract: Extensive previous studies confirmed that wavelength conversion may only marginally improve the solutions to the static Routing and Wavelength Assignment (RWA) problem. This means that, for the static RWA problem, certain RWA schemes that do not use wavelength conversion can achieve a performance almost as good as the one from the best RWA scheme. Previous research work on sliding scheduled RWA problems, where a given set of lightpath demands are allowed to slide within their time windows, has also indicated in limited simulation results that the benefit of using wavelength conversion is marginal. However, the observation cannot be conclusive without the solid mathematical proof. We are thus motivated to investigate whether schedule sliding really requires wavelength conversion to achieve a better performance. In this paper, we prove that wavelength conversion does not improve the Lagrangian bound of the sliding scheduled RWA problem. In most test cases, this bound is very close to the best achieved objective function value. Our proof implies that, for those cases, the improvements achieved by making use of wavelength conversion are very marginal. © 2012 Elsevier B.V. All rights reserved.

Source title: Computer Communications

Series Number: Volume 36 Issue 5

DOI: 10.1016/j.comcom.2012.12.003

Link: A proof of wavelength conversion not improving Lagrangian bounds of the sliding scheduled RWA problem NOTE: A login may be required to access this site.

Zhang, J.Y.; Wu, J.; Bochmann, G.V.
Improved doppler mitigation techniques for LTE uplink transmission

Year: 2013

Abstract: The third generation partnership project (3GPP) Long Term Evolution (LTE) uses Single-Carrier Frequency-Division Multiple Access (SC-FDMA) technology for uplink (UL) transmission. It has been shown that the SC-FDMA receivers are vulnerable to fast fading channels. In this paper, we first show that, although LTE UL system is based on OFDM, its performance is not sensitive to the inter-carrier-interference (ICI) due to Doppler effect in fast fading channels. The main challenge is to obtain accurate channel estimation with the limited number of time-domain pilot symbols. Next, we propose two improved channel estimation techniques: 1) pilot-aided cubic-Spline interpolator with time-domain noise filtering, 2) decision-directed channel estimation with time-domain noise filtering. We show by simulation that significant performance improvement is achieved by implementing the proposed techniques in both single-antenna LTE UL receivers and multiple-antenna receivers with diversity combining. © 2013 IEEE.

Source title: Proceedings - IEEE Military Communications Conference MILCOM

DOI: 10.1109/MILCOM.2013.27

Link: Improved doppler mitigation techniques for LTE uplink transmission

Zhang, L.; Hong, Z.; Boudreau, R.; Watson, S.; Jackson, B.
DIBR-based conversion from monoscopic to stereoscopic and multi-view video

Year: 2013

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. © Springer Science+Business Media New York 2013. All rights are reserved.

Source title: 3D-TV System with Depth-Image-Based Rendering: Architectures, Techniques and Challenges

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.
Goodput improvement for multipath TCP by congestion window adaptation in multi-radio devices

Year: 2013

Abstract: Multipath Transport Control Protocol (MPTCP) has been standardized by Internet Engineering Task Force (IETF) to support simultaneous delivery of transport control protocol (TCP) packets over multiple interfaces of multi-radio mobile devices. Although MPTCP provides an efficient solution to aggregate the available bandwidth of multiple paths, the goodput of MPTCP is usually far lower than the aggregate throughput due to out-of-order received packets. One key reason for the out-of-order issue is the large variation of end-to-end delay for multiple paths over wireless channels. In this paper, we propose a congestion window adaption algorithm for the MPTCP source (referred to as CWA-MPTCP), which dynamically adjusts the congestion window for each TCP subflow so as to mitigate the variation of end-to-end path delay. We consider typical multipath transmission scenarios over wireless links, as well as a cooperative multi-hop wireless network with multiple relays. For wired paths with stable end-to-end delay, we further develop a proactive scheduling algorithm to determine the packet sending sequence to each path. This algorithm effectively reduces the out-of-order packets by predicting the receiving sequence. Experiments are conducted to evaluate the goodput performance of the two enhancements to MPTCP. Significant performance gain is achieved in terms of goodput, while the receive buffer requirement is minimized. © 2013 IEEE.

Source title: 2013 IEEE 10th Consumer Communications and Networking Conference, CCNC 2013

DOI: 10.1109/CCNC.2013.6488491

Link: Goodput improvement for multipath TCP by congestion window adaptation in multi-radio devices

Zhou, D.; Song, W.; Shi, M.
1 W, highly efficient, ultra-broadband non-uniform distributed power amplifier in GaN

Year: 2013

Abstract: This letter describes the design and implementation of a highly linear, ultra-broadband non-uniform asymmetric distributed MMIC power amplifier in GaN, delivering 1 W of output power and suitable for operation at frequencies up to 6.5 GHz. The GaN HFETs used here have a gate length of 500 nm, and breakdown-voltages exceeding 100 V while exhibiting an fT of approximately 30 GHz. A non-uniform asymmetric distributed topology is used to achieve ultra-broadband performance. CW measurements carried out at nominal bias between 0.5 GHz and 6.5 GHz yielded a maximum PAE of 38.1% at 0.5 GHz, with PAE higher than 20% over the entire band, while achieving Pout > 30 dBm. © 2001-2012 IEEE.

Source title: IEEE Microwave and Wireless Components Letters

Series Number: Volume 23 Issue 4

DOI: 10.1109/LMWC.2013.2250270

Link: 1 W, highly efficient, ultra-broadband non-uniform distributed power amplifier in GaN

Zhou, X.; Roy, L.; Amaya, R.E.
An iterative calibration technique for LINC transmitter

Year: 2013

Abstract: The linear amplification using nonlinear components (LINC) is one of the most promising techniques that can simultaneously provide high efficiency and high linearity. However, it is sensitive to in-phase/quadrature imbalances in quadrature modulators (QMs), and to gain/phase mismatches between two PA paths. In this paper, we present an iterative calibration technique to compensate for the imbalances and mismatches, based on the observation that when the I/Q imbalances in the QM are ideally calibrated, the PA input signal has constant envelope, which allows the PA to be characterized as a linear gain model. It allows us to estimate the calibration parameters without modeling the nonlinear characteristics of the PAs. An adaptive implementation scheme is given. Simulation results demonstrate that the proposed technique accurately determines the calibration parameters, yielding significant performance improvement of the LINC transmitter. © 2013 IEEE.

Source title: Midwest Symposium on Circuits and Systems

DOI: 10.1109/MWSCAS.2013.6674666

Link: An iterative calibration technique for LINC transmitter

Zhu, Z.; Huang, X.
Theoretical and experimental studies of a probabilistic-based memoryless PA linearization technique

Year: 2013

Abstract: This paper studies the performance of a memoryless power amplifier (PA) linearization technique based on a probabilistic approach. This technique employs a nonparametric method to derive a predistorter function, which does not need any parametric modeling and explicit parameter estimation. It only needs to calculate a probabilistic cumulative distribution function (CDF) and a quantile function (an inverse function of the CDF). Histogram and order statistic methods are proposed to perform the calculation. A rigorous analytic formula is derived for the inter-modulation product power (IMPP) of the PA output signal when a finite number of samples as well as a finite number of bins are used to calculate the CDF and the quantile function. The analytic results show that, with the probabilistic-based technique, the IMPP approaches zero as the number of samples approaches infinity and the bin width approaches zero. Computer simulations are utilized to verify the theoretical analysis and to compare the performance of the probabilistic-based linearization technique with those of other memoryless PA linearization techniques, while a prototype experiment is carried out to demonstrate its performance in a practical application. Results show that the technique can accurately determine the predistortion function that effectively compensates for the nonlinearity in the PA, and that it achieves a much better linearization performance compared to other existing methods, especially in the presence of a loop delay in the feedback circuit. © 2013 Her Majesty the Queen in Right of Canada.

Source title: Circuits, Systems, and Signal Processing

Series Number: Volume 32 Issue 6

DOI: 10.1007/s00034-013-9612-5

Link: Theoretical and experimental studies of a probabilistic-based memoryless PA linearization technique

Zhu, Z.; Huang, X.; Caron, M.
A blind AM/PM estimation method for power amplifier linearization

Year: 2013

Abstract: A higher order statistics (HOS)-based method is proposed in this letter to estimate the nonlinear amplitude-to-phase (AM/PM) conversion function of power amplifiers (PAs) in communications systems. By utilizing the symmetry property of the modulated signal, the proposed method estimates the AM/PM conversion function using only the PA output signal, from which the phase predistorter (PD) function can be derived. Simulation results show that the HOS-based method can accurately determine the phase PD function required to compensate for the AM/PM distortion in the PA, yielding a linearization performance close to that of non-blind methods in terms of adjacent channel power ratio and error vector magnitude. © 2012 IEEE.

Source title: IEEE Signal Processing Letters

Series Number: Volume 20 Issue 11

DOI: 10.1109/LSP.2013.2280394

Link: A blind AM/PM estimation method for power amplifier linearization

Zhu, Z.; Huang, X.; Caron, M.; Leung, H.
Joint I/Q mismatch and distortion compensation in direct conversion transmitters

Year: 2013

Abstract: Analog and radio frequency (RF) front-end circuit impairments such as mismatches between in-phase (I) and quadrature (Q) branches can severely degrade performance of wireless communications systems. In this paper, we propose a technique to compensate for both frequency-independent and frequency-dependent impairments in direct conversion transmitters (DCTs). The technique employs a recursive algorithm to estimate the impairments from instantaneous power of the transmitted RF signal, and it jointly mitigates the mismatches/imbalances between the I and Q branches and the distortions in each of the I and Q branches. It is applicable to wireless communications systems that employ different modulation techniques. Theoretical analyses are presented for identifiability and convergence properties of the technique. Effects of imperfect measurement are discussed. Both computer simulation and prototype experimentation are carried out to demonstrate that the proposed technique accurately determines and compensates for the DCT impairment, and improves the transmitted signal quality. © 2002-2012 IEEE.

Source title: IEEE Transactions on Wireless Communications

Series Number: Volume 12 Issue 6

DOI: 10.1109/TCOMM.2013.050313.121256

Link: Joint I/Q mismatch and distortion compensation in direct conversion transmitters

Zhu, Z.; Huang, X.; Leung, H.
Challenges in reconfigurable radio transceivers and application of nonlinear signal processing for RF impairment mitigation

Year: 2013

Abstract: The design of compact and reconfigurable radio transceivers with low power consumption and low cost is a challenging task in future wireless communications systems. Transceiver architectures that are amenable to high-level integration will inevitably suffer from various radio frequency (RF) impairments, which limits the communications system performance and hence hinders their wide-spread use in commercial products. In this paper, we present the mitigation of RF impairments as a system identification problem. Four major classes of RF impairments are presented: power amplifier (PA) nonlinearity, in-phase/ quadrature (I/Q) impairments, group delay distortion, and carrier frequency offset and phase noise. Their models and up-to-date identification techniques are described here. In particular, various nonlinear signal processing techniques that are effective in mitigating these impairments are also presented here. Theoretical and experimental results show that these mitigation techniques can significantly improve the communications system performance. © 2001-2012 IEEE.

Source title: IEEE Circuits and Systems Magazine

Series Number: Volume 13 Issue 1

DOI: 10.1109/MCAS.2012.2237143

Link: Challenges in reconfigurable radio transceivers and application of nonlinear signal processing for RF impairment mitigation

Zhu, Z.; Leung, H.; Huang, X.
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