Consultation on Allocation Changes and Revisions to Spectrum Utilization Policy and Technical Rules in the 5 GHz Band

3. Proposed Revisions to Spectrum Utilization Policy and Technical Rules in the 5 GHz Range

The use of the frequency bands 5150-5250 MHz, 5250-5350 MHz and 5725-5825 MHz for licence-exempt wireless local area networks (LE-LANs) is currently governed under Spectrum Utilization Policy for Licence Exempt Wireless Local Area Networks in the 5 GHz Range (SP-5150 MHz).

In accordance with SP-5150 MHz, LE-LANs can be characterized as local transmission devices which provide a wide range of applications for high-speed broadband digital distribution applications comprising voice, video and data. These systems promise to provide high-speed connectivity for computers and multimedia neighbourhoods and will mainly consist of point-to-point and point-to-multipoint high-speed digital wireless services.

Industry Canada is providing funding to the Broadband for Rural and Northern Development initiative to help bring publicly available broadband access to Canadian communities, with priority given to First Nations, northern, remote and rural communities. The Broadband initiative is part of the Canadian government's commitment to ensuring broadband access for all Canadian communities by 2005. Along with other frequency bands, use of the 5 GHz band for LE-LANs provides valuable spectrum to assist Canadians in achieving this goal.

The Department intends to permit, in addition to the bands 5150-5250 MHz, 5250-5350 MHz and 5725-5825 MHz, the operation of local area networks in the band 5470-5725 MHz under appropriate policies, regulations and technical standards. In that regard, SP-5150 MHz will be revised accordingly.

In order to ensure the compatibility between all the existing and proposed radio services in the 5 GHz band, a number of technical and operational restrictions on LE-LAN devices are necessary. The following sections discuss the technical and operational requirements in each sub-band.

3.1 Sub-band 5150-5250 MHz

The band 5150-5250 MHz is currently allocated to the aeronautical radionavigation service on a primary basis. The band 5091-5250 MHz is also allocated to the fixed-satellite service (FSS) on a primary basis in the Earth-to-space direction, limited to feederlinks for non-geostationary systems in the mobile-satellite service. In addition, under Canadian Footnote C39A, the band 5150-5250 MHz is designated for use by LE-LANs based on not interfering with, nor claiming protection from, licensed services. The technical and operational limits are stated in Radio Standards Specification 210, Low Power licence-exempt Radiocommunication Devices (All Frequency Bands) (RSS-210).

International studies have concluded that, with appropriate power levels as well as technical and regulatory provisions, the sharing of spectrum among LE-LAN devices, existing aeronautical radionavigation service, and FSS feeder links for non-geostationary mobile-satellite service networks is feasible.

WRC-03 provided a global mobile service allocation for wireless access systems including radio local area networks in this band. Furthermore, stations in the mobile service shall not claim protection from earth stations in the fixed-satellite service. In addition, technical limits were imposed on the mobile service in order to ensure compatibility with other services.

A comparison between the existing domestic and newly adopted international technical and operational constraints on LE-LANs is provided in Table 1 below:

Table 1: Brief Summary of Technical and Operational Limits in the Band 5150-5250 MHz 6
Document Constraints
RSS-210

The maximum e.i.r.p. shall not exceed 200 mW or 10 + 10 log10 B, dBm, whichever power is less. B is the 99% power bandwidth in MHz. The power spectral density shall not exceed 10 dBm in any 1.0 MHz band (e.i.r.p.).

The band 5150-5250 MHz is restricted to indoor-only operation and the transmitter must be equipped with an integral antenna.

WRC-03 decisions

(see Appendix 3)

Maximum e.i.r.p. of 200 mW and a maximum e.i.r.p. density of 10 mW/MHz in any 1 MHz or equivalently 0.25 mW/25 kHz in any 25 kHz. The band 5150-5250 MHz is restricted to indoor only operation.

Administrations may monitor whether the aggregate power flux-density levels given in Recommendation ITU-R S.1426 7 have been, or will be exceeded in the future, in order to enable a future world radiocommunication conference to take appropriate action.

As shown in Table 1 above, Industry Canada's RSS-210 has already imposed the indoor-only operational restriction on LE-LANs in order to ensure compatibility with the FSSs operating in the same band. In addition, power limits, consistent with those adopted by the WRC, are also specified in the RSS. Provisions to allow mobile-satellite service operators to monitor emissions from LE-LAN devices in the band were also included in RSS-210.

The Department proposes that the existing technical rules as contained in RSS-210 pertaining to the band 5150-5250 MHz be maintained. The Department seeks views on this proposal.

3.2 Sub-band 5250-5350 MHz

The band 5250-5350 MHz is currently allocated to the Earth exploration-satellite, radiolocation, and space research services on a primary basis. In addition, under Canadian Footnote C39A, the band 5250-5350 MHz is designated for use by LE-LANs based upon not interfering with, nor claiming protection from licensed services.

This band has been designated for both indoor and outdoor LE-LAN products since 1999. Outdoor LE-LAN products have been used to provide broadband wireless access to customers for high-speed Internet applications. Prior to WRC-03, Canada was active in the international forum in ensuring that outdoor LE-LAN applications were accommodated while providing protection to the operation of other services operating in this band. A number of technical and operational restrictions were required in order to achieve this objective.

The Canadian Space Agency (CSA) operates a RADARSAT satellite in this band, which provides imagery data services to customers around the world.

The band 5250-5350 MHz is also used globally by military radiolocation systems.

As discussed in Section 2, WRC-03 made a global mobile service allocation for wireless access systems including Radio Local Area Networks in this band. Under the WRC provisions, stations in the mobile service shall not claim protection from the radiolocation, Earth exploration-satellite (active) and the space research (active) services. In addition, technical limits were imposed on the mobile service in order to ensure compatibility with other services.

The decisions of the WRC-03 represent a compromise among the various competing spectrum needs of the international community.

Specifically, due to the potential for interference into sensitive international Earth exploration-satellite instruments, there were strong representations from many countries to restrict the operation of LE-LAN to indoor-use only. A number of other countries were of the view that other mitigation techniques could be used to ensure compatibility between systems in the Earth exploration-satellite service and LE-LAN devices. These techniques include the use of an e.i.r.p. elevation angle mask as discussed below.

In addition, technical compatibility studies conducted by the International Telecommunications Union, in which Canada was an active participant have shown that sharing between LE-LAN devices and systems in the radiolocation service is possible provided certain technical constraints on the LE-LAN devices are adopted. These constraints include the use of dynamic frequency selection, as well as emission limits on LE-LANs. These constraints were adopted by WRC-03 in ITU Resolution 229 (WRC-03) as shown in Appendix 3 of this document.

Studies have shown that the e.i.r.p. elevation angle mask can be an effective mitigation technique to ensure compatibility with the EESS. Technologies such as the use of tilt sensors that vary the output power as a function of tilt angle of the device have demonstrated success in ensuring compliance with the e.i.r.p. elevation angle mask.

It was also stated by the WRC-03 that administrations could exercise some flexibility in adopting other mitigation techniques, provided that they develop national regulations to meet their obligations to achieve an equivalent level of protection to the EESS (active) and the SRS (active) based on their system characteristics and interference criteria as given in ITU-R SA.1632. 8

Furthermore, the requirement to use Dynamic Frequency Selection (DFS) as a mitigation technique to ensure compatibility with the radiolocation was adopted by WRC-03. The specific requirements are given in Recommendation ITU-R M.1652. 9 An excerpt from this recommendation is given in Appendix 2 of this document. In summary, the DFS mechanism is required to detect interference signals above a minimum DFS detection threshold of
-62 dBm for devices with a maximum e.i.r.p. of less than 200 mW and
-64 dBm for devices with a maximum e.i.r.p. of 200 mW to 1W averaged over 1 µs. The LE-LAN device should be able to perform a channel availability check on a particular channel for 60 seconds to identify whether a radar is operating on that radio channel. The LE-LAN device should also be able to perform in-service monitoring to detect the presence of radars. As well, a channel that has been flagged as containing a radar signal, either by a channel availability check or in-service monitoring, is subject to a 30-minute non-occupancy period where it cannot be used by the LE-LAN device in order to protect scanning radars.

A comparison between the existing domestic and newly adopted international technical and operational constraints on LE-LANs is provided in Table 2 below:

Table 2: Brief Summary of Technical Limits in the Band 5250-5350 MHz 10
Document Constraints
RSS-210

The maximum transmitter power shall not exceed 250 mW or 11 + 10 log10 B, dBm, whichever power is less. B is the 99% power bandwidth in MHz. The power spectral density shall not exceed 11 dBm in any 1.0 MHz band.

The maximum e.i.r.p. shall not exceed 1.0 watt or 17 + 10 log10 B, dBm, whichever power is less. B is the 99% power bandwidth in MHz.

WRC-03 decisions

(See Appendix 3)

Maximum e.i.r.p. shall be limited to 200 mW and a maximum e.i.r.p. density of 10 mW/MHz in any 1 MHz band.

Administrations are requested to take appropriate measures that will result in the predominant number of stations being operated in an indoor environment.

Furthermore, stations which are permitted to be used either indoors or outdoors may operate up to a maximum e.i.r.p. of 1W and maximum e.i.r.p. density of 50 mW/MHz in any 1 MHz. When operating above an e.i.r.p. of 200 mW, stations shall comply with the following e.i.r.p. elevation angle mask where θ is the angle above the local horizontal plane (of the Earth): 

-13 dB(W/MHz) for 0° ≤ θ < 8°
-13 - 0.716 (θ-8) dB(W/MHz) for 8° ≤ θ < 40°
-35.9 - 1.22 (θ-40) dB(W/MHz) for 40° ≤ θ < 45°
-42 dB(W/MHz) for 45° < θ

Administrations may exercise some flexibility in adopting other mitigation techniques, provided that they meet their obligations to achieve an equivalent level of protection to the EESS (active) and SRS (active) services based on their system characteristics and interference criteria as given in Recommendation ITU-R SA.1632.

Systems in the mobile service shall either employ transmitter power control to provide, on average, a mitigation factor of at least 3 dB on the maximum average output power of the systems, or, if transmitter power control is not in use, then the maximum e.i.r.p. shall be reduced by 3dB. Stations shall implement dynamic frequency selection.

The Department believes that the decisions taken at WRC-03 represent a well-balanced compromise among the competing spectrum needs. Of particular importance to Canada was the provision to allow the use of outdoor LE-LANs. As discussed previously, the Department is of the view that the capability for LE-LANs to operate outdoors will be essential to connect rural and remote communities. At the same time, the Department recognizes that LE-LANs, consistent with Canadian Footnote C39A, shall not cause harmful interference into other licensed services, such as the Earth exploration-satellite service and radiolocation service operating in the same band. With all elements of sharing considered, the Department believes that the decision taken by WRC-03 will protect the incumbent services appropriately while allowing LE-LANs to operate in indoor and outdoor environments.

In light of the above discussion, the Department is proposing to revise, where appropriate, a Radio Standard Specification, to incorporate the following technical rules on LE-LANs: 

  1. Stations are permitted to be used both indoors or outdoors; and
  2. The maximum e.i.r.p. shall not exceed 1.0 watt or 17 + 10 log10 B, dBm, whichever power is less. B is the 99% power bandwidth in MHz; and
  3. When operating above an e.i.r.p. of 200 mW, stations shall comply with the following e.i.r.p. elevation angle mask where θ is the angle above the local horizontal plane (of the Earth): 

    -13 dB (W/MHz) for 0° ≤ θ < 8°
    -13-0.716 (θ-8) dB(W/MHz) for 8° ≤θ < 40°
    -35.9 - 1.22 (θ-40) dB(W/MHz) for 40° ≤ θ < 45°
    -42 dB(W/MHz) for 45° < θ

  4. Systems in the mobile service shall either employ transmitter power control to provide, on average, a mitigation factor of at least 3 dB on the maximum average output power of the systems, or, if transmitter power control is not in use, then the maximum e.i.r.p. shall be reduced by 3dB.
  5. Stations shall implement dynamic frequency selection.

The Department invites comments on these proposals.

The Department also invites comments on the following: 

  1. Recognizing that mitigation techniques such as dynamic frequency selection and e.i.r.p.elevation angle mask are required to ensure compatibility with the EESS (active) and radiolocation services, what are the technical implications and feasibility of implementing these techniques in the design of LE-LANs in this band?
  2. The Department notes that, under the ITU Radio Regulations, administrations may exercise some flexibility in adopting other mitigation techniques, provided that they meet their obligations to achieve an equivalent level of protection to the EESS (active) and SRS (active) services based on their system characteristics and interference criteria as given in Recommendation ITU-R SA.1632. The Department seeks views and evidence on other mitigation techniques that may be available.
  3. The Department also seeks comments on appropriate test and certification procedures to ensure compliance by mobile devices and systems with dynamic frequency selection, automatic power control and e.i.r.p. elevation angle mask in this band.
  4. Given that the current technical rules for this band have been in place since 1999, the Department proposes that the new technical requirements be effective a year from the date of publication of the appropriate spectrum utilization policy.

3.3 Sub-band 5470-5725 MHz

The band 5470-5725 MHz is, or will be, shared by a number of radio services (see Appendix 1) including the radiodetermination service, Earth exploration-satellite (active) service, and space research (active) service in various sub-bands within this frequency range.

As discussed before, the United States has recently amended their rules governing the operation of unlicensed National Information Infrastructure (U-NII) devices, including Radio Local Area Networks (RLANs), and has made available an additional 255 MHz of spectrum in the band 5470-5725 MHz.

Also, as discussed in Section 2, WRC-03 made a global mobile service allocation for wireless access systems including Radio Local Area Networks in this band. Under the WRC provisions, stations in the mobile service shall not claim protection from the radiodetermination service. In addition, technical limits were imposed on the mobile service in order to ensure compatibility with other services.

Similar to the band 5250-5350 MHz, Earth exploration-satellite systems will utilize the band 5470-5725 MHz for many synthetic aperture radar-related applications. However, sharing between LE-LANs and the Earth exploration-satellite systems is less restrictive in the band 5470-5725 MHz than in the band 5250-5350 MHz. The wide-band synthetic aperture radars (SARs), which will operate in the band 5250-5725 MHz are less susceptible to interference than the SARs that operate in the band 5250-5350 MHz. This will enable the LE-LANs to operate with higher power and less operational restrictions compared to the band 5250-5350 MHz.

Furthermore, as discussed in the previous section, the use of dynamic frequency selection as a mitigation technique to ensure compatibility with the radiolocation was adopted by WRC-03.

The band 5600-5650 MHz is used heavily in Canada for national meteorological radars. These radars provide weather related data for Environment Canada. Their operation is different than conventional terrestrial scanning radars. In order to protect their operation from aggregate emissions of LE-LAN devices, the ITU-R had developed special provisions in Recommendation ITU-R M.1652 for the band 5600-5650 MHz. An excerpt from this recommendation is given in Appendix 2 of this document. In this Recommendation, it is stated that "in the band 5600-5650 MHz, if a channel has been flagged as containing a radar, a 10-minute continuous monitoring of the flagged channel is required prior to use of that channel. Otherwise, other appropriate methods such as channel exclusion would be required." This 10-minute continuous monitoring requirement may be performed during the 30-minute non-occupancy period. The non-occupancy period is described in Section 3.2 of this document.

A comparison between the existing domestic and newly adopted international technical constraints on LE-LANs is provided in Table 3 below:

Table 3: Brief Summary of Technical Limits in the Band 5470-5725 MHz 11
Document Constraints
RSS-210 Not applicable.
WRC-03 decisions

(See Appendix 3)
Stations shall be restricted to a maximum transmitter power of 250 mW with a maximum e.i.r.p. of 1W and a maximum e.i.r.p. density of 50 mW/MHz in any 1 MHz band.

Systems in the mobile service shall either employ transmitter power control to provide, on average, a mitigation factor of at least 3 dB on the maximum average output power of the systems, or, if transmitter power control is not in use, then the maximum e.i.r.p. shall be reduced by 3 dB.

Stations shall implement dynamic frequency selection, including special provisions (described previously) pertaining to the band 5600-5650 MHz.

In light of the above discussion, the Department is proposing to revise, where appropriate, a Radio Standard Specification, to incorporate the following technical rules on LE-LANs: 

  1. Stations are permitted to be used both indoors or outdoors.
  2. The maximum transmitter power shall not exceed 250 mW.
  3. The maximum e.i.r.p. shall not exceed 1.0 watt or 17 + 10 log10 B, dBm, whichever power is less. B is the 99% power bandwidth in MHz.
  4. Systems in the mobile service shall either employ transmitter power control to provide, on average, a mitigation factor of at least 3 dB on the maximum average output power of the systems, or, if transmitter power control is not in use, then the maximum e.i.r.p. shall be reduced by 3 dB.
  5. Stations shall implement dynamic frequency selection, including the special provisions pertaining to the band 5600-5650 MHz. The special provisions pertaining to the band 5600-5650 MHz require that in the band 5600-5650 MHz, if a channel has been flagged as containing a radar, a 10-minute continuous monitoring of the flagged channel is required prior to use of that channel. Otherwise, other appropriate methods such as channel exclusion are required.

The Department invites comments on these proposals.

The Department also invites comments on the following:

  1. Recognizing that mitigation techniques, such as DFS, are required to ensure compatibility with EESS (active) and the radiolocation service, what are the technical implications and the feasibility of implementing these techniques in the design of LE-LANs in this band?
  2. The Department also seeks comments on appropriate test and certification procedures to ensure compliance by mobile devices and systems with dynamic frequency selection, and automatic power control.

4. Conclusion

Based upon the results of the public consultation initiated by this discussion paper, a revised Canadian Table of Frequency Allocations will be prepared and issued. As well, appropriate spectrum utilization policy and technical standards will be revised and published.

Issued under the authority
of the Radiocommunication Act

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Robert McCaughern
Director General
Spectrum Engineering Branch

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Larry Shaw
Director General
Telecommunications Policy Branch


Footnotes

  1. back to footnote reference 6 Information contained in this table is a summary only. Further restrictions may apply. Consult SP-5150 MHz, RSS-210, ITU Resolution 229 (WRC-03), or appropriate domestic/international footnote(s) for detailed descriptions of the technical and operational limits applicable to this frequency band.
  2. back to footnote reference 7 The maximum aggregate power flux-density given in Recommendation ITU-R S.1426 is: 
    -124 - 20 log10 (hSAT/ 1 414) dB(W/(m2 · 1 MHz)), or equivalently,
    -140 - 20 log10 (hSAT / 1 414) dB(W/(m2 · 25 kHz)), at the FSS satellite orbit,
    where hSAT is the altitude of the satellite (km).
  3. back to footnote reference 8 Recommendation ITU-R SA.1632:  Sharing in the band 5 250-5 350 MHz between the Earth exploration-satellite service (active) and wireless access systems (including radio local area networks) in the mobile service.
  4. back to footnote reference 9 Recommendation ITU-R M.1652:  Dynamic frequency selection in wireless access systems including radio local area networks for the purpose of protecting the radiodetermination service in the 5 GHz band.
  5. back to footnote reference 10 Information contained in this table is a summary only. Further restrictions may apply. Consult SP-5150 MHz, RSS-210, ITU Resolution 229 (WRC-03), or appropriate domestic/international footnote(s) for detailed descriptions of the technical and operational limits applicable to this frequency band.
  6. back to footnote reference 11 Information contained in this table is a summary only. Further restrictions may apply. Consult SP-5150 MHz, RSS-210, ITU Resolution 229 (WRC-03), or appropriate domestic/international footnote(s) for detailed descriptions of the technical and operational limits applicable to this frequency band.
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