Closing date for comments: March 10, 2023
Closing date for reply comments: April 14, 2023
Expand all content / collapse all content Annexes
Through the release of this document, Innovation, Science and Economic Development Canada (ISED), on behalf of the Minister of Innovation, Science and Industry (the Minister), is hereby initiating a technical consultation on the Standard Radio System Plan SRSP-520, issue 3, Technical Requirements for Fixed and/or Mobile Systems, Including Flexible Use Broadband Systems, in the Band 3450-3900 MHz (the SRSP) and the Radio Standards Specification RSS-192, issue 5, Flexible Use Broadband Equipment Operating in the Band 3450-3900 MHz (the RSS).
In spring 2020, ISED published two technical standards, SRSP-520, issue 1, Technical Requirements for Fixed and/or Mobile Systems, Including Flexible Use Broadband Systems, in the Band 3450-3650 MHz and RSS-192, issue 4, Flexible Use Broadband Equipment Operating in the Band 3450-3650 MHz, based on the Policy and Licensing Framework for Spectrum in the 3500 MHz Band. These standards were published in preparation for the 3500 MHz spectrum auction, which was held in June 2021. The standards provide co-existence and coordination requirements between flexible use operations and other in-band and adjacent band services and certification requirements for 3500 MHz flexible use equipment.
In May 2021, ISED published SLPB-002-21, Decision on the Technical and Policy Framework for the 3650-4200 MHz Band and Changes to the Frequency Allocation of the 3500-3650 MHz Band (the 3800 MHz Policy Decision). This 3800 MHz Policy Decision sets rules around the treatment of incumbents, including wireless broadband services (WBS), fixed services (FS) and fixed satellite services (FSS).
Following the publication of the 3500 MHz technical rules and the 3800 MHz Policy Decision, spectrum and aviation regulators around the world, including ISED, became aware of studies that showed the possibility of interference to radio altimeters (which are crucial safety-of-life aviation sensors) operating in the 4200-4400 MHz band from signals outside their band of operation, which could include signals from flexible use 5G systems in both the 3450-3650 MHz (3500 MHz) and 3650-3900 MHz (3800 MHz) bands.
In order to protect radio altimeters, on November 18, 2021, ISED published the Decision on Amendments to SRSP-520, Technical Requirement for Fixed and/or Mobile Systems, Including Flexible Use Broadband Systems, in the Band 3450-3650 MHz, which included mitigation measures to protect radio altimeter operations from potential harmful interference from flexible use systems in the 3500 MHz band, as set forth in issue 2 of SRSP-520.
The main protection measures included:
- exclusion and protection zones to mitigate interference to aircraft around certain airport runways where automated landing is authorized;
- a national antenna down-tilt requirement to protect aircraft used in low altitude military operations, search and rescue operations and medical evacuations throughout the country.
On December 23, 2021, Transport Canada released a Civil Aviation Safety Alert to raise awareness of the potential risk of 5G interference and to recommend precautionary operational measures before confirmation of the impact of 5G systems on radio altimeters. Transport Canada’s recommendations included advising operators to identify all possible indications that might be evidence of possible radio altimeter disturbance in their aircraft and ensure that this information is provided to flight crews, to perform risk assessments and if required, to implement procedures and operational restrictions.
In June 2022, ISED published SPB-002-22, Policy and Licensing Framework for Spectrum in the 3800 MHz Band (the 3800 MHz Licensing Framework Decision), which extended the mitigation measures for the 3500 MHz band to the 3650-3900 MHz band while international and domestic studies were still underway to further assess the potential adjacent band interference to radio altimeters from flexible use operations. The aforementioned document also provided the timeframe of October 2023 for the start of the 3800 MHz spectrum auction.
ISED has now completed its studies on the co-existence between radio altimeters and 5G operations. Through the release of this document, ISED is hereby consulting on the technical requirements for the 3500 MHz and 3800 MHz bands. Proposed updates to the technical requirements in the SRSP and RSS reflect the results of new studies, in addition to requirements that reflect the policy decisions in the 3800 MHz Policy Decision and the 3800 MHz Licensing Framework Decision.
3. International context
Over the last few years, spectrum regulators around the world have released or are planning to release mid-band spectrum in the 3 GHz range to support the next generation of commercial mobile services, known as fifth generation (5G). At the same time, given concerns regarding the potential for interference from 5G services to radio altimeters in the adjacent bands, regulators have also been assessing the potential impact and determining appropriate measures to address such concerns. Aviation organizations have also been conducting studies on this potential impact to radio altimeters.
3.1 United States
In the United States (US), the Federal Communications Commission (FCC) completed the auction of the 3700-3980 MHz and 3450-3550 MHz bands for 5G operations in February 2021 and January 2022, respectively. Technical rules were established to enable the co-existence of different services in-band and in adjacent bands, including equipment certification requirements. These rules include flexible use base station equivalent isotropically radiated power (e.i.r.p.) limits of 62 dBm/MHz in urban areas and 65 dBm/MHz in rural areas, an e.i.r.p. limit of 30 dBm for mobile and portable devices, unwanted emission limits of -13 dBm/MHz (conducted power), a power flux density (pfd) limit of 16 dBW/m2/MHz as measured at the earth station antenna and receiver performance thresholds for earth stations required for co-existence between FSS and 5G services.
In December 2021, prior to the official launch of their 5G services in the 3800 MHz band, A&T and Verizon agreed to limit deployments around airports through voluntary measures that would remain in place until July 2022. Following discussions with the US Federal Aviation Agency (FAA), they later committed to keeping these measures in place until July 2023.
In January 2022, the FAA began imposing restrictions on flight operations using certain types of radio altimeters at airports with low-visibility approaches. For helicopters, the FAA allowed for air ambulance operators to continue using safety-enhancing night vision goggles in areas where the aircraft’s radio altimeter could be unreliable due to 5G operations. In June 2022, the FAA released a statement introducing a phased retrofit approach, requiring operators of regional aircraft with radio altimeters most susceptible to interference to be retrofitted with radio frequency filters by the end of 2022. The retrofit of remaining commercial aircraft with susceptible radio altimeters would need to be completed by July 2023. After July 2023, mobile network operators would be able to operate their networks with minimal restrictions. However, discussions are still on-going in the US on these restrictions.
In October 2022, the US National Telecommunications and Information Administration (NTIA) published a report on the Measurement of 5G New Radio Spectral and Spatial Emissions for Radar Altimeter Interference Analysis. The work described in the report entailed:
- Measurements of the wideband, wide dynamic range emission spectra of all three models of 5G base station transmitters that are being deployed in the US in 3700–3980 MHz; and
- Three-dimensional airborne measurements of actual emission patterns of 5G multiple-input multiple-output (MIMO) arrays for those same radio models, plus a fourth model that operates in slightly lower frequency spectrum.
One conclusion drawn in the report was that the low measured 5G spurious emission power levels (between -37.5 dBm/MHz and -48.5 dBm/MHz) from macro-cell base stations reduced the potential for harmful interference to radio altimeters in the 4200-4400 MHz band which would be associated with 5G unwanted emissions. Another finding was that airborne 5G emission patterns showed measurably, significantly less power compared to 5G base station main antenna beams directed toward user terminals at ground level. In addition, airborne field strength data showed that all 5G MIMO arrays have significantly reduced power relative to the main antenna-beam levels at the skyward zeniths above the arrays. A final conclusion was that emissions from closer base stations were dominant in a receiver, with emissions from further base stations rapidly fading to insignificance.
In France, the 3490-3800 MHz band was auctioned for commercial mobile services in the fall of 2020. Commercial outdoor base stations can operate up to 78 dBm e.i.r.p., with unwanted emission limits for these base stations harmonized with ECC CEPT Report 67. Shortly after the auction, in November 2020, France mandated measures to protect radio altimeters until more studies could be completed. These measures include zones (available only in French) around certain airports and around certain heliports, and a national antenna down-tilt requirement. The antenna down-tilt requirement was scaled back in March 2021, once more information was obtained on the types of radio altimeters used on military and emergency services helicopters. France noted that these mitigation techniques would not protect the most sensitive category 2 and 3 radio altimeters found on regional aircraft and helicopters. Protecting these radio altimeters would restrict any deployments of 5G over their national territory.
In 2019, Brazil identified segments in the 3300-3700 MHz range for commercial mobile operation (available only in Portuguese), with base stations limited to a maximum e.i.r.p of 65 dBm/10 MHz (or 55 dBm/MHz). In addition, the spurious emission limit for base stations without active antenna system (non-AAS) is ‑30 dBm/MHz and -21 dBm/MHz for base stations employing AAS. In June 2022, Brazil imposed, through the publication of Act No. 9064 (available only in Portuguese), power restrictions and antenna down-tilt requirements around certain aerodromes to protect radio altimeters from 5G operations in the 3300-3700 MHz range. These mitigation measures have been put in place until December 31, 2022, while domestic and international developments on the radio altimeter issue progress.
In Australia, commercial 5G services have been in operation since early 2019 in the 3400–3700 MHz band and arrangements are being developed to support 5G services up to 4000 MHz. To date, there have not been any confirmed reports of radio altimeter interference from 5G operations. The Australian regulator, Australian Communications and Media Authority (ACMA), has been collaborating with the telecommunications and aviation sectors in Australia to examine the issue further and determine how to achieve co-existence between 5G and radio altimeters, with initial compatibility studies conducted in 2020. With respect to managing the radio altimeter issue, ACMA has cited its well-established practices to ensure that when new services are introduced into a spectrum band, the potential for interference with existing services is managed, including close engagement with all potentially affected parties, the conduct of appropriate technical studies and monitoring of developments internationally.
In Japan, commercial 5G services have been in operation since 2018. The frequency range of operation is 3600-4100 MHz, where the maximum e.i.r.p. limits are set at 48 dBm/MHz for macro-cell base stations and 25 dBm/MHz for small-cell base stations. According to a working paper within the International Civil Aviation Organization - Frequency Spectrum Management Panel (ICAO FSMP), in order to mitigate interference to radio altimeters, the location of macro-cell 5G base stations should be avoided within 200 metres from the approaching route of an aircraft. For heliports, the working paper indicates that 5G base stations should be kept at a physical distance of at least 50 metres for a macro-cell station and at least 20 metres for a small-cell station.
While other countries across Europe and elsewhere in the world have released parts of the 3 GHz range for 5G commercial mobile services, this issue continues to be studied by some countries; ISED is not aware of any restrictions being imposed in those countries to protect radio altimeters from potential interference from adjacent band 5G services.
In addition to these developments around the world, in October 2020, the Radio Technical Commission for Aeronautics (RTCA) published a report outlining the potential for harmful interference to radio altimeters operating in the 4200-4400 MHz band from 5G operations in the 3800 MHz band. In April 2022, Aerospace Vehicle Systems Institute (AVSI) published a report with additional data, drawing similar conclusions to those in the RTCA 2020 report.
To address concerns of potential interference, the RTCA formed a committee (SC-239) designated to update the current Minimum Operational Performance Standards (MOPS) for Low Range Radar Altimeters, DO-155A, in order to protect future radio altimeters from interference. This update is intended to enable the efficient use of near-band spectrum by setting a standard for new radar altimeters that provides state-of-the-art, near-band rejection while maintaining the current intended functions of radar altimeters. The MOPS is scheduled to be completed by December 2023.
4. Domestic context
Similar to other countries (see section 3), ISED has released mid-band spectrum in the 3 GHz range for 5G commercial mobile services. This includes the 3450-3650 MHz band, where 5G operations have already been deployed in Canada since June 2022.
As mentioned above, in the 3500 MHz band, ISED currently has technical requirements in place to enable the co-existence of 5G with other in-band and adjacent band services. These requirements, amongst others, include mitigation measures to protect radio altimeters in the 4200-4400 MHz band – exclusion and protection zones around certain airport runways where automated landing is authorized and a national antenna down-tilt requirement to protect aircraft used in low-altitude operations across the country. Outside of the exclusion and protection zones, 5G systems can operate at a maximum e.i.r.p. of 68 dBm/5 MHz (or 61 dBm/MHz) for non-AAS systems and a maximum total radiated power (TRP) of 47 dBm/5 MHz (or 40 dBm/MHz) for AAS systems in urban and rural areas, with an unwanted emission limit of -13 dBm/MHz (TRP or conducted).
The exclusion zones were developed to protect radio altimeters when aircraft are operating at 200 feet above ground – where an error in a radio altimeter reading could be catastrophic for automated landing systems. Protection zones were developed to protect radio altimeters when aircraft are operating between 200 feet and 1000 feet above ground – situations in which air crew workload would be high. The protection zones currently include a pfd limit of -38.80 dBW/m2/MHz at 300 feet above ground, which was derived from radio altimeters in RTCA usage category 1— commercial air transport airplanes, both single-aisle and wide-body (see annex C of Addendum to Consultation on Amendments to SRSP-520, Technical Requirement for Fixed and/or Mobile Systems, Including Flexible Use Broadband Systems, in the Band 3450-3650 MHz). Moreover, as outlined in the aforementioned decision, ISED imposed a national antenna down-tilt requirement for 5G base stations similar to the original requirement in France, given that ISED could not confirm all types of radio altimeters in use on helicopters pending the completion of further investigation and study of helicopter scenarios.
Through the release of the 3800 MHz Policy and Licensing Framework Decisions, ISED allowed 5G commercial mobile services in the 3650-3900 MHz band. The 3800 MHz Licensing Framework Decision provided the October 2023 timeframe for the 3800 MHz spectrum auction. As outlined in the 3800 MHz Policy Decision, in order to provide incumbents with time to transition to other spectrum bands, 5G deployments would take place in urban and rural areas in March 2025 and March 2027, respectively. When the 3800 MHz Licensing Framework Decision was released, studies on radio altimeter issues were still ongoing. As an interim measure, ISED decided to extend the mitigation measures applicable to the 3500 MHz band, to flexible use operations in the 3800 MHz band while studies were ongoing.
ISED has now completed a series of studies, including laboratory testing of several radio altimeter models, qualitative and quantitative over-the-air (OTA) testing with the use of various radio altimeters, and a computational analysis. A technical summary on each of these study streams is provided in annex A. The main conclusions are described below.
In the laboratory study, six of the eleven radio altimeters tested were impaired by 5G fundamental emissions operating across the 3450-4000 MHz frequency range for all altitudes tested. However, it was demonstrated that adding band-pass filtering at the input of the radio altimeter receiver can mitigate 5G fundamental interference. Additionally, when considering all radio altimeters tested at all fixed altitudes, a high disparity was observed in terms of susceptibility to spurious emissions.
In the OTA study, no observable anomalies were reported by flight crews during the qualitative assessment. A quantitative assessment was also performed using a fully instrumented research aircraft equipped with seven radio altimeters to further assess 5G susceptibility. Three radio altimeters, two of which were the same model, were found to be susceptible to 5G fundamental emissions. Susceptibility events were identified across the 3500 MHz, 3800 MHz and 3900 MHz bands and at all fixed-flight altitudes. These susceptibility events ranged from approximately 0.5 to 9 seconds, with an average duration of approximately 2.3 seconds. Based on a voluntary survey performed by Transport Canada in January 2022 and ISED’s engagements with the Department of National Defence (DND) and air ambulance operators, these two radio altimeter models, classified as category 2 and 3, are commonly installed on regional aircraft and helicopters in Canada. These models are part of the first phase of the US FAA’s retrofit plan described in section 3.
Finally, in the computational analysis study, results demonstrate that specific isosceles trapezoidal-shaped exclusion and protection zones would be necessary to provide protection to category 1 aircraft using instrument landing systems (ILS) runways. The antenna down-tilt requirement would provide additional protection to helicopters in rural areas but would have minimal impact in urban centres due to clutter and building shadowing. Further, for category A helicopters landing or departing from H1 classified heliports, specific exclusion zones and protection zones would protect these aircraft from outdoor base stations. Additionally, a spurious emission level of -33 dBm/MHz was deemed sufficient to protect radio altimeters.
Following the work described above, ISED has determined that there continues to be a risk of harmful interference to certain radio altimeters. ISED remains committed to ensuring the safety of Canadians. Efforts are underway by some aircraft operators and radio altimeter manufacturers to retrofit and replace specific radio altimeters. Until susceptible radio altimeters are replaced, ISED, through the results of these studies and in consultation with Transport Canada, has developed revised measures required to protect the operation of radio altimeters for different aviation scenarios, while allowing the deployment of 5G systems in Canada. As such, ISED is proposing updated requirements to apply to flexible use systems in both the 3450-3650 MHz and 3650-3900 MHz bands, as described in section 5 and section 6, below. Following the consultation period, as discussed in section 7, new requirements will be published by spring 2023, well in advance of the start of the 3800 MHz auction in October 2023.
5. Proposed amendments to SRSP-520
Proposed changes to SRSP-520 are provided in annex B. As discussed above, the frequency range for fixed and mobile systems, including flexible use broadband systems has been extended from 3450-3650 MHz to 3450-3900 MHz, based on the 3800 MHz Policy Decision which allows flexible use services in the 3650 MHz-3900 MHz band.
Based on the results of domestic studies outlined in section 4 and annex A, proposed mitigation measures to be imposed on 5G operation in the 3500 MHz and 3800 MHz bands to protect radio altimeters have been revised accordingly.
The proposed exclusion zones, currently rectangular and extending 910 metres on either side of the runway edge and 2100 metres from the runway thresholds, have been revised to be formed of two segments: a rectangle having the same length as the runway and a width of 640 metres centred on the centreline of the runway; and an isosceles trapezoid, with a starting base width of 640 metres centred around the runway centreline and extending 2100 metres from the runway threshold, with an ending base width of 1269 meters, as per the red shapes below in figures 1a) and 1b).
It was found that different protection zones are required for the 3500 MHz and 3800 MHz bands. Specifically, the protection zones that currently extend from the edge of each exclusion zone to 6100 metres, with a width of 1000 metres, have been revised as follows:
- for 3500 MHz, an isosceles trapezoid extending 1000 metres from the edge of the exclusion zones, with an ending base width of 1568 metres, as per the blue shape in figure 1a) below;
- for 3800 MHz, an isosceles trapezoid extending 2500 metres from the edge of the exclusion zones, with an ending base width of 2017 metres, as per the blue shape in figure 1b) below; and
- if a base station operates in both the 3500 MHz and 3800 MHz bands, the 3800 MHz protection zone in figure 1b) would apply.
Figure 1: Revised exclusion zones (red) and protection zones (blue) for 3500 MHz (figure 1a) and 3800 MHz (figure 1b)
Figure 1 description:Figure 1 illustrates the protection zones around airport runways. It illustrates two figures: the protection and exclusion zones for the 3500 MHz frequency band (above) and 3800 MHz frequency band (below). Both figures illustrate a runway surrounded by an exclusion zone. The exclusion zones are red unfilled shapes composed of two segments. The first segment is a rectangle having the same length as the runway and a width of 640 metres centred on the centreline of the runway. The second segment is an isosceles trapezoid centred on the centreline of the runway that extends 2100 metres from the runway threshold. The width of the red trapezoid at the runway threshold is 640 metres and the width of the trapezoid 2100 metres from the runway threshold is 1269 metres. For the 3500 MHz frequency band figure, the protection zones are blue unfilled isosceles trapezoids centred on the centreline of the runway with a length of 1000 metres, extending from the edge of the exclusion zones (i.e. the exclusion zone boundary). The width of the blue trapezoid at the exclusion zone boundary is 1269 metres, and the width of the blue trapezoid is 1568 metres at a distance of 1000 m from the exclusion zone boundary. For 3800 MHz frequency band figure, the protection zones are blue filled isosceles trapezoids centred on the centreline of the runway with a length of 2500 metres, extending from the edge of the exclusion zones (i.e. the exclusion zone boundary). The width of the blue trapezoid at the exclusion zone boundary is 1269 metres, and the width of the blue trapezoid is 2017 metres at a distance of 2500 m from the exclusion zone boundary.
The shapes of the exclusion and protection zones have been adapted to account for the flight path of an aircraft when descending towards an ILS surface, which has been found to deviate from a straight line in the middle of a runway. Moreover, in order to protect an aircraft at an altitude of 1000 feet or less from a base station operating at 68 dBm/5 MHz e.i.r.p., new pfd limits have been derived for protection zones. Base stations within protection zones would be required to meet a skyward pfd limit of -34.21 dBW/m2/5 MHz at 350 feet above ground and a pfd limit of -23.45 dBW/m2/5 MHz at the boundary of exclusion zones (at 325 feet above ground) to protect aircraft in the critical phase of final descent. In addition, a maximum e.i.r.p. of 77.5 dBm per carrier will apply.
ISED will continue to protect the same 26 airports and 43 runways, identified in ISED’s Map of Exclusion Zones and Protection Zones, where automated landing has been authorized, based on the most susceptible category 1 radio altimeter.
As mentioned in section 4, ISED imposed a national antenna down-tilt requirement for 5G base stations to protect low altitude military operations, search and rescue and medical evacuation operations, while the susceptibility of radio altimeters on helicopters was studied further. During the previous consultation on issue 2 of SRSP-520, ISED heard from telecommunication stakeholders that base station antennas may be up-tilted to serve mid- and high-rise buildings (e.g. multi-dwelling units) that are usually located in built up urban areas. ISED’s computational analysis, together with available information on radio altimeter models installed on helicopters in Canada, has since shown that an antenna down-tilt requirement is still warranted for low altitude military operations, search and rescue and medical evacuation operations, which would typically take place outside core centres. ISED’s computational analysis study also showed that up-tilting 5G base station antennas has minimal impact on co-existence with radio altimeters when a base station is pointed at a building, due to building shadowing, as well as in certain dense urban areas where clutter is a factor. As such, ISED is proposing to remove the antenna down-tilt requirement in large population centres (LPCs)1. With some building shadowing and clutter loss possible in medium population centres (MPCs)2, the antenna down-tilt restriction could potentially be removed in those areas as well, although low altitude helicopter operations may be more likely in MPCs than in LPCs. Additionally, ISED found that limiting the vertical scanning below the horizon had little impact when the combined digital and mechanical tilts were already kept below the horizon. Therefore, ISED is proposing to remove vertical scanning from its definition of down-tilt and base down-tilt restrictions solely on the combination of mechanical and digital tilt.
For category A helicopter operations in core city centers, ISED determined that exclusion and protection zones around H1 classified heliports (see annex D) would protect the critical phases of departure and landing, posing the strictest performance requirements at these aerodromes. As such, ISED is proposing exclusion zones of 80 metres in radius, measured from the centre of the final approach and take-off area (FATO), around H1 heliports where the deployment of outdoor base stations would not be permitted. Moreover, ISED has determined that protection zones of 500-1000 metres in radius, depending on clutter, are needed around H1 heliports, also measured from the centre of FATOs. Within these protection zones, outdoor base stations would be required to limit their emissions towards heliports by meeting a pfd limit of -41 dBW/m2/5 MHz at the heliport surface, within the 50-metre circular boundary measured from the FATO’s centre. The zone sizes are based on analysis of St. Michael’s Hospital heliport (CTM4), in downtown Toronto, which is one of the heliports in Canada with the strictest landing and departing constraints for helicopter performance, due to the heliport height and congested building surroundings. ISED will continue to study the impact of clutter and decide on more precise sizes for these protection zones.
All of the above proposed requirements for 5G operations in the 3450-3900 MHz band to protect radio altimeters will be put in place until March 31st, 2025. After this date, mitigation measures imposed on 5G operations are intended to be removed. The 2025 sunset date will provide approximately two additional years from the US FAA’s July 2023 date to replace or upgrade susceptible radio altimeters. Moreover, it will provide time for aircraft to be retrofitted based on the RTCA’s MOPS (DO-155A standard), which is planned to be released by end of 2023.
Notwithstanding the above, ISED will closely monitor domestic and international activities related to the co-existence between 5G operations and radio altimeters, and in discussion with Transport Canada and other stakeholders, may adjust the sunset date, if required. If the sunset date is extended beyond 2025, ISED could consider extending mobile network operators’ flexible use licence terms accordingly.
While the proposed mitigation measures outlined above are similar to the mitigation measures imposed in other countries (see section 3), ISED is seeking comments on whether additional mitigation measures on 5G operations should be considered to protect radio altimeters.
ISED is seeking comments on the proposed exclusion and protection zones to protect category 1 aircraft landing at the 26 airports and 43 runways where automated landing is authorized, identified in ISED’s Map of Exclusion Zones and Protection Zones.
ISED is seeking comments on the proposal to maintain the antenna down-tilt requirement outside of LPCs to protect low altitude military operations, search and rescue operations and medical evacuations. ISED is also seeking comments on whether MPCs should also be excluded from the antenna down-tilt requirement.
ISED is seeking comments on the proposed exclusion and protection zones around 58 H1 classified heliports, as listed in annex D, to protect helicopters.
For protection zones around the 58 H1 classified heliports, as ISED continues its analysis of zone sizes and given that that heliport heights and clutter can differ from one heliport to the next, ISED is seeking comments on whether the same protection zone sizes should be applied across Canada or whether different sizes should be applied at each heliport, despite potential operational complexity for 5G operators.
ISED is seeking comments on whether additional mitigation measures should be imposed on 5G operations in the 3500 MHz and 3800 MHz bands.
In addition to the proposed changes above and in line with the 3800 MHz Policy Decision, the SRSP also introduces new technical requirements for flexible use licensees to facilitate co-existence with other incumbent services in-band and in adjacent bands, including FSS and FS. For co-existence with FSS earth stations, the technical requirements were derived assuming a co-channel (in-band) interference-to-noise (I/N) protection threshold of -10 dB, an adjacent-band I/N protection threshold of -12 dB, an FSS earth station receiver noise temperature of 70K, and an earth station antenna height of 5 metres. For new and transitioned earth stations operating in the 4000-4200 MHz band, it was assumed that these earth stations would meet the FSS receiver filter parameters in annex G of the draft revision to SRSP-520 to receive protection, as well as a -59 dBm saturation limit.
ISED is seeking comments on the proposed technical requirements for flexible use licensees to facilitate co-existence with FSS and FS, as outlined above and specified in annex B.
6. Proposed amendments to RSS-192
Proposed changes to RSS-192 are provided in annex C. These changes are consistent with the frequency range for flexible use equipment, which is being extended from 3450-3650 MHz to 3450-3900 MHz based on the 3800 MHz Policy Decision.
Based on the results of ISED’s domestic studies (see section 4 and annex A), the RSS includes a proposed spurious emission limit of -33 dBm/MHz in the 4200-4400 MHz band, the operating band of radio altimeters, to minimize the potential for harmful interference to these aviation sensors. Existing base stations generate spurious emission levels well below the current -13 dBm/MHz spurious emission limit. Therefore, the new proposed limit should be easily achievable, without the need for manufacturers to modify existing 5G base station equipment currently available on the Canadian market and operating in the 3500 MHz band, nor have 3800 MHz equipment specifically developed for Canada.
In addition to the above changes, the proposed e.i.r.p. limit for indoor base stations was increased from 33 dBm to 39 dBm TRP and subscriber equipment other than fixed subscriber was revised from 23 dBm/10 MHz to 30 dBm e.i.r.p. These proposed power limits are closely harmonized with the US requirements for the certification of equipment operating in a similar frequency range. ISED considered increasing the power limits for non-AAS and AAS equipment. However, no changes were made to these power limits considering the potential for interference to susceptible radio altimeters. Once the retrofit of susceptible radio altimeters has been completed, ISED could consider revising these power limits to align with the US base station ecosystems and other global markets.
ISED is seeking comments on the proposed changes to RSS-192, as outlined above and specified in annex C.
7. Next steps
ISED will review the comments received and publish an updated SRSP and RSS after the closing of the technical consultation.
8. Submitting comments
Respondents are requested to provide their comments in electronic format (Microsoft Word or Adobe PDF) by email no later than March 10, 2023. Soon after the comment period, all comments received will be posted on ISED’s Spectrum Management and Telecommunications website.
ISED will also provide interested parties with the opportunity to reply to comments from other parties. Reply comments will be accepted until April 14, 2023.
9. Obtaining copies
All spectrum-related documents referred to in this paper are available on ISED's Spectrum Management and Telecommunications website.