Consultation Paper on the Introduction of Wireless Systems Using Ultra-wideband Technology

4. Discussion and Proposals

4.1 Definitions and Terminology

The following set of UWB definitions and terminology is used by the UWB industry. This set is also similar to the UWB definitions and terminology of the FCC and those under development by the ITU-R.

UWB bandwidth: The frequency band bounded by the points that are 10 dB below the highest radiated emission, as based on the complete transmission system including the transmit antenna. The upper and lower –10 dB frequency points are referred to as ƒ_H and ƒ_L, respectively.

UWB centre frequency:  The centre frequency, ƒ_C, of an UWB emission is given by,

ƒ_C = (ƒ_H + ƒ_L)/2.

UWB fractional bandwidth:  The fractional bandwidth of an UWB emission is defined as:

FBW(%) = 2(ƒ_H - ƒ_L)*100 / (ƒ_H + ƒ_L)

UWB device: An intentional radiator or a receiver that operates using UWB technology and has a bandwidth equal to or greater than 0.5 GHz or a fractional bandwidth equal to or greater than 20%.

UWB activity factor:  For applications that do not require the devices to operate continuously, this represents the fraction of time during which an UWB device is actively servicing the application.

Pulse transmitter duty cycle:  For pulse generated UWB, during the period in which the UWB transmitter is active, this is the ratio of the impulse duration to the time between the start of two adjacent impulses.

UWB system:  A wireless system that consists of at least one UWB transmitter and an associated receiver.

The Department proposes the use of the above UWB definitions and terminology.

4.2 Technical Considerations

4.2.1 Emission Limits

In an effort to control the potential interference from UWB systems, emission limits should be established.  Industry Canada notes that the Federal Communications Commission (U.S.) and the European Conference of Post and Telecommunications Administrations (CEPT) have adopted or drafted e.i.r.p. density emission masks for UWB systems as listed in Tables 3 and 4, respectively.

Table 3 - FCC Emission Limits (dBm/MHz) for Various UWB Systems

UWB System	GPR, Wall and Through-wall Imaging	Through-wall Imaging, and Fixed Surveillance	GPR, Wall Imaging, and Medical Imaging	Communications and Measurement		Vehicular Radar
Frequency Band	UWB bandwidth below 960 MHz	UWB bandwidth in 1.99– 10.6 GHz	UWB bandwidth in 3.1–10.6 GHz	Indoors	Hand-held devices including outdoors	Anti-collision radar and other field disturbance sensors
≤960 MHz	The radiated emissions at or below 960 MHz shall not exceed the emission levels in Section 15.209 of the FCC Part 15 UWB rules (Radiated emission limits; general requirements).
960-1 610 MHz	-65.3	-53.3	-65.3	-75.3	-75.3	-75.3
1 610-1 990 MHz	-53.3	-51.3	-53.3	-53.3	-63.3	-61.3
1 990-3 100 MHz	-51.3	-41.3	-51.3	-51.3	-61.3	-61.3
3.1-10.6 GHz	-51.3	-41.3	-41.3	-41.3	-41.3	-61.3
10.6-22.0 GHz	-51.3	-51.3	-51.3	-51.3	-61.3	-61.3
22.0-29.0 GHz	-51.3	-51.3	-51.3	-51.3	-61.3	-41.3
29.0-31.0 GHz	-51.3	-51.3	-51.3	-51.3	-61.3	-51.3
Above 31.0  GHz	-51.3	-51.3	-51.3	-51.3	-61.3	-61.3

It should be noted that the maximum emission levels of the FCC and draft CEPT masks are identical in the range 3.1–10.6 GHz and have the same value as the licence-exemption level for conventional (non-UWB) wireless systems (RSS-210^{[ref. 2]}).

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4.2.2 Aggregate Interference

Industry Canada has conducted technical studies on compatibility between UWB and radiocommunication devices^{[ref. 3]}. Below is a summary of the results of the studies performed by the Canadian Communications Research Centre (CRC) on aggregate interference from a multitude of UWB sources at 5 GHz.

The aggregate interference from randomly distributed UWB emitters was analyzed using five different propagation (free-space, log-normal shadowing, random propagation factor using uniformly distributed random variables for the path loss exponent and the shadowing attenuation level, two-ray, and modified two-ray) models in an outdoor environment. A uniformly random distribution of UWB devices was used to evaluate the aggregate interference of multiple UWB devices. The victim receiver was located at the centre of this distribution. For each distribution, the UWB emitters were sorted by distance from the victim receiver. The interfering power spectral density (PSD) level was calculated at the input of the antenna of the victim receiver as a function of the number of emitters by distance from the victim receiver. The emission level for each UWB device was at an e.i.r.p. spectral density of –41.3 dBm/MHz.

The simulation results show that the median cumulative power spectral density increases rapidly as a function of the number of UWB emitters up to a certain value beyond which the PSD level increases very slowly with the number of emitters. As shown in Figures 1 and 2, this value varies with the propagation model used in the analysis. In addition, Figures 1 and 2 show that the median cumulative PSD over different numbers of random distributions does not vary with the number of distributions when the number of distributions is sufficiently large.

Figure 1. Median Cumulative PSD versus Number Of UWB Emitters in a 100 M x 100 M Zone

For each propagation model there are two lines: one for 50 random distributions (i.e. thin lines) and the other for 200 random distributions (i.e. thick lines). The propagation models are free-space (solid lines), log-normal shadowing (dashed lines) and random propagation factor (dash-dot lines).

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Figure 2. Median Cumulative PSD versus Number of UWB Emitters in a 100 M x 100 M Zone

For each propagation model there are two lines: one for 80 random distributions (i.e. thin lines) and the other for 200 random distributions (i.e. thick lines). The propagation models are two-ray (solid lines) and modified two-ray (dashed lines).

4.2.3 Measurement of UWB Emissions

One of the key issues for assessing interference levels, determining compatibility, and for certifying equipment is the establishment of appropriate measurement methodologies. Proper methodologies for the measurement and assessment of power and field strength are required for compliance with standards and specifications and may be useful for the purpose of spectrum monitoring. UWB devices can transmit at a low spectral power density to deliver a large amount of data across several GHz of spectrum. UWB devices may have pulsed emissions with fast rise-times. Thus UWB challenges the way radio frequency measurements are made for conventional radiocommunication systems. Appropriate measurement methods are needed for:

• power spectral density;
• peak power level; and
• other measurements (e.g. pulse repetition frequency, etc.).

The Department proposes the following guidelines for measuring UWB emissions:

• The spectrum is to be investigated from the lowest frequency generated in the UWB transmitter, without going below 9 kHz. If the UWB center frequency is less than 10 GHz, then there is no requirement to measure emissions beyond 40 GHz. There is no requirement to measure emissions beyond 100 GHz if the UWB center frequency is at or above 10 GHz and below 30 GHz; or beyond 200 GHz if the UWB center frequency is at or above 30 GHz.
• Radiated UWB emissions are to be made based on power spectral density measurements in terms of e.i.r.p. per one MHz spectral segments. The measurement is to be based on the use of a spectrum analyzer employing a 10 kHz integration bandwidth. If the transmission is in bursts, measurements are to be made over any 100 millisecond period or over the burst duration if the burst is shorter than 100 milliseconds, during which its power value is at its maximum.
• Peak power measurements are to be centered on the frequency at which the highest radiated emission occurs.

4.3 Regulatory and Licensing Considerations

There are three different options that could potentially be used to address the authorization requirements of devices using UWB technology in Canada.

1. A Licensing Approach
   • The traditional licensing approach used by Industry Canada has been to process most applications for radio facilities and assign frequencies for a specific location for which a "radio licence" is issued. Another type of radio authorization called a "spectrum licence" is also being used to accommodate the concept of area licensing. Spectrum licences are authorized by geographical area(s) and frequencies or frequency block(s). Both these licensing processes are provided for in the Radiocommunication Act^{[ref. 4]} and the Radiocommunication Regulations^{[ref. 5]}.
   • UWB is a wireless technology and not a radiocommunication service. However, it can be integrated into various wireless services. In addition, it is envisaged that UWB will be integrated into a variety of applications including consumer devices and vehicular radar. Therefore the traditional approaches of radio and spectrum licensing may not be adequate for some UWB applications.
2. A Licence-exempt Approach
   • The Radiocommunication Act (section 6(2)) and the Radiocommunication Regulations provide a regulatory scheme whereby licence exemptions on the basis of a technical standard for certain radio apparatus may be articulated in appropriate equipment standard specifications. Such radio apparatus are exempt from the requirement to operate under a radio licence, but are instead authorized by way of certification to appropriate Industry Canada Radio Standards Specifications (RSS). Such radio apparatus are operated in accordance with the Department's policies.
   • A new RSS could be developed to permit UWB devices to operate on a licence-exempt basis under technical conditions that would provide a level of interference protection for licensed radiocommunication systems. Licence-exemption requirements for UWB devices could also be included into an existing standard such as RSS-210^{[ref. 2]}.
3. A User-eligibility Based Approach
   This option would allow some user groups to operate specific UWB equipment on a licence-exempt basis under certain conditions. The UWB equipment would have to comply with specific radio standards specifications and be certified. UWB devices operated under this option would have to bear a statement specifying the eligible user groups (e.g. law enforcement agencies, scientific research institutes, fire and emergency rescue organizations). Under such an option, the Radiocommunication Regulations would have to be amended to allow specific user groups to operate certain UWB systems without the requirement of a licence. A potential consequence of this option is that it may be difficult to find a flexible regulatory framework to address future requirements to include additional user groups and /or additional UWB equipment.

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5. Invitation to Comment

Industry Canada wishes to identify public interests and issues relevant to the introduction of various types of UWB devices in Canada. Interested parties are invited to respond to the following questions:

• (Q1) Sections 3.1 and 3.2 of this consultation describe potential benefits and concerns relevant to the introduction of wireless devices using ultra-wideband (UWB) technology. Please provide additional interests and/or concerns that you may have.
• (Q2) The Department proposes to use the set of definitions and terminology in Section 4.1 in reference to UWB technology. Is this set adequate and if not, what would be the appropriate alternative(s)?
• (Q3) The Department is proposing guidelines in Section 4.2.3 for measuring emissions from devices which use UWB technology. Please provide your comments regarding these guidelines.
• (Q4) The Department is of the view that licensing is a valid approach to authorize ground penetrating radar, wall imaging, and through-wall imaging devices that use UWB technology. The Department is considering limiting the use of these devices to specialized user groups (e.g. law enforcement agencies, scientific research institutes, fire and emergency rescue organizations) and of limiting area(s) of operation. Please provide your comments regarding this licensing approach.
• (Q5) UWB will be integrated into various wireless applications including consumer devices (e.g. lap-tops, home theatre, etc.) and into transportation vehicles (e.g. vehicular radars, road sensors, etc.). These applications will be mass distributed in markets and may be acquired both in Canada and abroad. Consequently the Department is of the view that a licence-exempt approach is a valid regulatory option to authorize these devices. These devices must comply with specific radio standards specifications and be certified. Please provide your comments on the use of an appropriate approach for authorizing UWB consumer devices, UWB communications and measurement devices, UWB vehicular radars, and UWB field disturbance sensors.
• (Q6) Considering the FCC and the proposed CEPT emission masks for UWB systems, what emission masks and what other, if any, measures (operational restrictions, etc.) would protect authorized radiocommunication services from harmful interference and would not impede the development of UWB devices?

Please supply the rationale with technical studies as appropriate with your comments or response to the above questions. Please consider the feasibility of implementing and enforcing various licensing options, as well as their implication on the market and trade. Please show how your proposal is in the public interest and explain the implication on the UWB industry (e.g. cost of producing UWB devices and marketability) and on radiocommunication services (e.g. quality of service and additional costs for radiocommunication services).

6. Next Step

In developing the appropriate regulatory tools for ultra-wideband, the Department will consider the status of ultra-wideband wireless communication applications in the market, standardization developments within the ultra-wideband industry, other regional and international regulatory and technical developments, as well as the results of ongoing compatibility studies. The cost and feasibility of implementing and enforcing various regulatory and licensing options and their implication on trade, the ultra-wideband industry, and on radiocommunication services will also be taken into consideration.

Based on these factors and considering public comments on this consultation, the Department anticipates that it will develop policies, standards, certification and/or licensing requirements to oversee the introduction and use of ultra-wideband technology in Canada. These factors and comments may also provide a basis for further consultations.

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7. References

¹ First Report and Order on ultra-wideband (UWB) technology, ET Docket 98-153, Federal Communications Commission, Washington, D.C., USA, April 2002.
² Radio Standards Specifications 210: Low Power Licence-Exempt Radiocommunication Devices (All Frequency Bands), Industry Canada, Issue 5, November 2001, http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf01320.html
³ Suitability of some propagation models to analyse interference from ultra wideband transmitters in outdoor environments, Q. Zeng, Communications Research Centre Canada, IEEE Conference on Ultra Wideband Systems and Technologies, Reston, Virginia, USA, November 2003, pp. 488-492.
⁴ Radiocommunication Act, Industry Canada, Issue 5, September 1996, http://laws.justice.gc.ca/en/R-2/index.html
⁵ Radiocommunication Regulations, Industry Canada, Issue 7, January 2002, http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf01265e .html

Issued under the authority
of the Radiocommunication Act

January 28, 2005

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Annex:  Acronyms

BPSK: Binary Phase Shift Keying

CEPT: European Conference of Post and Telecommunications Administrations

CITEL: Inter-American Telecommunication Commission

E.I.R.P. / e.i.r.p.: Effective isotropic radiated power

ETSI: European Telecommunications Standards Institute

FCC: Federal Communications Commission

GPR: Ground Penetrating Radar

GMSK: Gaussian Minimum Shift Keying

IEEE: Institute of Electrical and Electronics Engineers

ISM: Industrial, Scientific, and Medical

ITU-R: International Telecommunications Union (Radiocommunications Bureau)

NTIA: National Telecommunications and Information Administration

OFDM: Orthogonal Frequency Division Multiplexing

PSD: Power Spectral Density

PPM: Pulse Position Modulation

QPSK: Quadrature Phase Shift Keying

QAM: Quadrature Amplitude Modulation

RABC: Radio Advisory Board of Canada

RF: Radiofrequency

RLAN: Radio Local Area Network

RSS: Radio Standards Specifications

UWB: Ultra-wideband

WPAN: Wireless Personal Area Network