With the publication of Industry Canada RSS-220 in March of this year, manufacturers are now able to certify and market their UWB (Ultra-Wideband) equipment in Canada. Following the publication of FCC (Federal Communications Commission) UWB rules in Part 15 Subpart F by 7 years, the new RSS-220 rules largely follow FCC equipment categories and limits. However, the Industry Canada limits are more stringent in part than the FCC’s for hand held and indoor communication devices. Test methods and equipment labeling also differ somewhat between the FCC and IC rules.
BACKGROUND
Ultra-wideband technology offers the promise of high bandwidth communications over short distances, using simple nanosecond pulse techniques. First developed for military applications, UWB is finding a variety of applications such as wireless personal area networks (WPANs), vehicular radar and ground penetrating radar (GPR). It offers system simplicity, relative immunity from interference and secure communications.
In operation, UWB spreads its low-power emissions over a very large frequency bandwidth, often greater than 500 MHz. This presents a threat of harmful interference to existing radio users. As an unlicensed service, any number of UWB transmitters could be concentrated in a small area, causing elevation of the local radio noise floor and potentially hindering operation of sensitive receivers.
UWB IN THE UNITED STATES
Mindful of both the potential benefits and drawbacks of UWB, the FCC in 2000 and 2001 sought public comment on allowing UWB operation under Part 15 (unlicensed) rules. It also sought comments on NTIA (National Telecommunications and Information Administration) studies on the potential interference to government systems from UWB operation. Hundreds of comments were received from radio equipment manufacturers, satellite service providers, the US Departments of Defense, Navy and Transportation, NAV Canada, local law enforcement and public safety agencies and radio amateurs, among others.
The result of these considerations was the adoption in February 2002 of Part 15 Subpart F rules for Ultra-Wideband Transmission Systems, FCC 02-48. The emission limits are lower than existing Part 15 general limits in 15.209 in most cases, and take into account the directionality of such uses as GPR and wall-penetrating radars to reduce the threat of interference to nearby receivers. The 2002 UWB rules have been modified several times since their publication, to account for specific technical issues such as gated transmissions.
To date, the FCC has issued about 180 Grants of Authorization for UWB devices of all types. Authority to issue UWB Grants has not yet been given to TCBs (Telecommunication Certification Bodies), accredited, independent certification bodies. The FCC will likely release the UWB certification authority to TCBs, as with other new technologies, once sufficient experience has been gathered and necessary test procedures have been defined.
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Figure 1: Typical UWB pulse and resulting emission profile |
UWB IN CANADA
In February 2005 Industry Canada published a “Consultation Paper on the Introduction of Wireless Systems Using Ultra-wideband Technology” (SMSE-002-05). The paper provides a concise statement of the potential benefits and problems associated with UWB devices. It surveys other UWB rules and drafts at the time of publication, including CEPT (European Conference of Postal and Telecommunications Administrations), ETSI (European Telecommunications Standards Institute), FCC, and IEEE (Institute of Electrical and Electronics Engineers). It contains simulations of the aggregate interference from multiple UWB devices, and observes from the simulations that the cumulative interference effect rises slowly after a sufficient number of UWB emitters (approximately 20 in the charts) are represented. The consultation paper also invited public comment on a number of specific procedural and technical questions.
On May 28, 2009 the radio equipment certification standard RSS-220 “Devices Using Ultra-Wideband (UWB) Technology” came into force. Prior to that date no UWB device could be certified for operation in Canada. Now, UWB equipment for use in Canada can be certified by the Canadian Certification and Engineering Bureau, and by the numerous accredited, independent Canadian Certification Bodies (CBs).
COMPARING FCC AND INDUSTRY CANADA UWB RULES
Structure
Here we compare the structures of the two sets of rules, noting differences in definitions, limits and test procedures. As many of the emission limits are identical, we will note only where differences exist.
Table 1 indicates the correlation between the two sets of rules.
Some of the key non-technical differences are:
- FCC Subpart F groups all definitions into section 15.503. RSS-220 distributes the definitions among the relevant subclasses, plus general definitions in the Annex.
- RSS-210 contains special requirements for test reports; FCC Subpart F does not.
- FCC Subpart F prohibits UWB use in toys and onboard aircraft; RSS-220 does not.
- Some labeling requirements differ; these are discussed below.
- The FCC UWB measurement procedures are found in Annex F of FCC 02-28. RSS-220 contains its own measurement procedures.
- FCC Subpart F imposed coordination requirements on UWB imaging device users. RSS-220 contains no coordination requirements.
Both documents define the key UWB parameters identically:
- UWB bandwidth (> 500 MHz)
- Fractional bandwidth (> 0.2)
- fM (Frequency of maximum UWB transmission)
- fH (Highest frequency at which the power spectral density of the UWB transmission is –10 dB relative to fM
- fL (Lowest frequency at which the power spectral density of the UWB transmission is –10 dB relative to fM
The –10 dBm bandwidth for UWB is used because the spectral power density is already so low that the more commonly used –20 dB points could be impossible to measure.
| Subject | FCC Part 15 section | Industry Canada RSS-220 section |
| Scope | 15.501 | 1 |
| Definitions | 15.503 | 2, 4, 5.2, 5.3, 6, 6.2, 6.3, 6.4, 6.5, Annex |
| Certification required | 15.201 | 3 |
| Cross-references | 15.505 | 3.1, RSS-Gen |
| Test reports | – | 3.2, note UWB subclass and any data port |
| Transmitter with external frequency selection controls | – | 3.3 |
| Marketing of UWB equipment | 15.507 | – |
| Ground-penetrating and wall imaging systems | 15.509 | 6.2, term “in-wall” used |
| Through-wall imaging systems | 15.510 | 6.3 |
| Surveillance systems | 15.511 | 6.4 |
| Medical imaging systems | 15.513 | 6.5 |
| Vehicular radar systems | 15.515 | 4 |
| Indoor UWB systems | 15.517 | 5.2 |
| Hand held UWB systems | 15.519 | 5.3 |
| General requirements | 15.521; also, operation of toys and onboard aircraft prohibited. | Annex |
| Measurement procedures | 15.523 (FCC 02-48 Annex F) | Annex |
| Coordination requirements | 15.525 (Imaging devices only) | – |
| Label or User Manual text | 15.510(e), 15.511(f), 15.517(f) | 6.2, 6.3, 6.4, 6.5 |
Table 1: Correlation between FCC and Industry Canada UWB rules
Limit Differences
Most of the limit values specified in RSS-220 are identical to those in FCC Subpart F. The general limits of 15.209 (identical to RSS-220 clause 3.4) apply below 960 MHz. In the GPS protection band 1164-1610 MHz, both compliance standards specify a > 1 kHz resolution bandwidth; the limits in this band are identical between standards (but differ among UWB device types) and can be as low as –85.3 dBm EIRP.
However, there are two cases where RSS-220 limits are more stringent than FCC Part 15 Subpart F, and the frequency breakpoints differ from Subpart F.
- Indoor UWB systems, FCC 15.517, RSS-220 clause 5.2.
The RSS-220 emission limit is more severe than the FCC Subpart F limit over the range 1.61 – 4.75 GHz (Table 2). The largest difference is 28.7 dB. The lower limit represents a measurement challenge, as the FCC Part 15 general limit (15.209) is the equivalent of –41.3 dBm EIRP in one MHz above 960 MHz. - Hand held UWB systems, FCC 15.519, RSS-220 clause 5.3.
| Frequency | FCC 15.517(c) EIRP in 1 MHz | IC RSS-220 clause 5.2.1(d) EIRP in 1 MHz |
| 960-1610 MHz | -75.3 dBm | -75.3 dBm |
| 1.61-1.99 GHz | -53.3 dBm | -70 dBm |
| 1.99-3.1 GHz | -51.3 dBm | -70 dBm |
| 3.1-4.75 GHz | -41.3 dBm | -70 dBm |
| 4.75-10.6 GHz | -41.3 dBm | -41.3 dBm |
| Above 10.6 GHz | -51.3 dBm | -51.3 dBm |
Table 2: Indoor UWB System Limit Comparison
Once again the RSS-220 emission limit is more severe than the FCC Subpart F limit over the range 1.61 – 4.75 GHz (Table 3). The largest difference is 28.7 dB, as with Table 2. The FCC Part 15 general limit (15.209) is the equivalent of –41.3 dBm EIRP in one MHz above 960 MHz.
| Frequency | FCC 15.519(c) EIRP in 1 MHz | IC RSS-220 clause 5.3.1(d) EIRP in 1 MHz |
| 960-1610 MHz | -75.3 dBm | -75.3 dBm |
| 1.61-1.99 GHz | -63.3 dBm | -70 dBm |
| 1.99-3.1 GHz | -61.3 dBm | -70 dBm |
| 3.1-4.75 GHz | -41.3 dBm | -70 dBm |
| 4.75-10.6 GHz | -41.3 dBm | -41.3 dBm |
| Above 10.6 GHz | -61.3 dBm | -61.3 dBm |
Table 3: Hand-held (outdoor) UWB System Limit Comparison
The Canadian limits for these two UWB types differ from FCC UWB limits in order to protect Canadian radio services such as WiMAX (2300 MHz, 3500 MHz) and Fixed-Satellite Service (FSS) communications in the C-band (3700-4200 MHz), which are different from US allocations.
Measurement Procedures
Industry Canada RSS-220 contains its own UWB measurement procedures in its Annex. By contrast, FCC Part 15 Subpart F addresses its measurement procedures by reference in clause 15.523. The procedures are found in FCC 02-48 Annex F, and agree with the procedures in RSS-220 on these major points:
- Measurements at and below 960 MHz are made with a CISPR quasi-peak detector
- Measurements above 960 MHz are made with an RMS detector having 1 MHz resolution bandwidth and < 1 ms averaging time.
- Peak EIRP measurements for comparison with the 0 dBm limit are made with any resolution bandwidth (RBW) from 1 MHz to 50 MHz, and scaled to a 50 MHz bandwidth using the formula 20 log10(RBW/50).
- Peak EIRP limit can be converted to field strength using the formula E(dBmV/m) = P(dBm EIRP) + 95.2.
- Emissions from digital circuitry not directly associated with operation of the UWB transmitter are subject to the respective limits for digital devices.
RSS-220 measurement procedures anticipate the desirability of making low-level UWB measurements in anechoic or semi-anechoic chambers. Several provisions for this, that are not found in FCC procedures, are:
- Below 960 MHz, assess the ground screen reflection contribution, if any, and correct the radiated emission measurements accordingly.
- Above 960 MHz in a semi-anechoic chamber, place RF absorbers between the EUT and the measurement antenna to remove the influence of the ground screen.
- For Ground Penetrating Radars, place the EUT over at least 50 cm of sand (same as FCC), or use a combination of ferrite tiles and dielectric cones placed directly below the EUT. If use of the bed of sand precludes a ground screen, the data must be adjusted to account for the absence of the ground screen.
FCC measurement procedures are more specific than RSS-220 in specifying a 4.7 dB correction factor for the absence of a ground screen, and in calling for a ½” thick gypsum or drywall to be used for testing through-wall imaging systems.
Labeling and User Manual Text Differences
For the manufacturer seeking to market the same UWB devices in both the USA and Canada, technical differences between the UWB standards in these two countries represent the first challenge. Not to be overlooked, however, are any differences in requirements in device labeling and user manual instructions. Fortunately, there are no conflicting requirements between RSS-220 and FCC Part 15 Subpart F in this area. Use restrictions in the FCC UWB rules that are required to be placed on the device label, are reflected in RSS-220 requirements for similar text in the user manual. In both cases the manufacturer must add the label and user manual text specified elsewhere in the Part 15 or RSS-Gen rules. Table 4 summarizes label and user manual requirements.
| Device type | FCC Subpart F text | RSS-220 text |
| Ground Penetrating Radar (GPR) and In-wall Imaging Systems | 6.2 GPR User Manual This Ground Penetrating Radar Device shall be operated only when in contact with or within 1 m of the ground. This Ground Penetrating Radar Device shall be operated only by law enforcement agencies, scientific research institutes, commercial mining companies, construction companies, and emergency rescue or firefighting organizations. 6.2 In-wall Imaging Systems User Manual This In-wall Radar Imaging Device shall be operated where the device is directed at the wall and in contact with or within 20 cm of the wall surface. This In-wall Radar Imaging Device shall be operated only by law enforcement agencies, scientific research institutes, commercial mining companies, constructyion companies, and emergency rescue or firefighting organizations. |
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| Through-wall imaging systems | 15.510(e) Label Operation of this device is restricted to law enforcement, emergency rescue and firefighter personnel. Operation by any other party is a violation of 47 U.S.C 301 and could subject the operator to serious legal penalties. | 6.3 User Manual This Through-wall Radar Imaging Device shall be operated only by law enforcement agencies or emergency rescue or firefighter organizations that are under a local, provincial or federal authority. The equipment is to be operated only in providing services and for necessary training operations. |
| Radar surveillance systems | 15.511(f) Label Operation of this device is restricted to law enforcement, fire and rescue officials, public utilities and industrial entities. Operation by any other party is a violation of 47 U.S.C 301 and could subject the operator to serious legal penalties. | 6.4 User Manual This Radar Surveillance Device shall be operated only by military, law enforcement, emergency rescue or firefighting organizations that are under a local, provincial or federal authority. The equipment is to be operated only in providing services and for necessary training operations. |
| Indoor UWB Systems | 15.517(f) Label or User Manual This equipment may only be operated indoors. Operation outdoors is in violation of 47 U.S.C 301 and could subject the operator to serious legal penalties. | |
| Medical Imaging Systems | 6.5 User Manual This Medical Radar Imaging Device shall be operated only in hospitals and health-care facilities, and only at the direction or under the supervision of a health-care practitioner. |
Table 4: Label and user manual text requirements for UWB devices
CONCLUSION
The Canadian equipment certification standard RSS-220 for UWB devices is very similar to the FCC technical requirements of UWB devices under 47 CFR Part 15 Subpart F. In many cases limits and methods are identical. However, there are significant differences between these rules for indoor and hand held UWB systems. Manufacturers seeking to market their UWB equipment in Canada, or in both countries, need to be aware of these differences, and of details in the standards that are beyond the scope of this overview. 
