Framework for the Use of Certain Non-broadcasting Applications in the Television Broadcasting Bands Below 698 MHz
7. Television White Space Implementation
Comments were sought on several proposals regarding the technical provisions for TVWS devices in Canada, which included defining TVWS categories, identifying operating channels, protecting other services and developing general technical provisions for the operation of TVWS devices near the Canada-United States border.
7.1 Television White Space Categories
The consultation proposed the following definitions for TVWS service categories:
Fixed white space device: A white space device that transmits and/or receives radiocommunication signals at a specified fixed location. The fixed device selects radio frequency channels for operation from a list of available channels provided by a TV band database.
Mobile white space device: A white space device that transmits and/or receives radiocommunication signals while in motion or at unspecified fixed points.
- Mode I mobile white space device: A mobile white space device that does not use an internal geo-location capability and does not directly access a TV band database to obtain a list of available radio frequency channels. Mode I mobile devices may also be referred to as "slave" devices. A Mode I device must obtain a list of available channels on which it may operate from either a fixed device or a Mode II mobile device. A Mode I device does not initiate a network of white space devices or provide a list of available radio frequency channels to another Mode I device for use by such a device.
- Mode II mobile white space device: A mobile white space device that uses an internal geo-location capability and accesses a TV band database for a list of available radio frequency channels. Mode II devices may also be referred to as "master" devices. Access to the database may be through a direct connection to the Internet or through an indirect connection via another fixed or Mode II white space device. A Mode II device may provide its list of available radio frequency channels to another mobile device for use by that device.
7.1.1 Summary of Comments
- Not all respondents comment on the TVWS categories. Of those who do, most respondents suggest harmonization with the U.S. definitions.
- Nokia does not believe that device implementation or innovation should be bound or restricted by predefined device categories.
- Neul does not see a need to distinguish between fixed and mobile devices, but prefers the convention used in the United Kingdom of having two classes: a "master" and a "slave."
- Some respondents are not clear on the use of the term "mobile" in the proposed definitions and sought clarification regarding its meaning. Shure and the WRAN Alliance recommend that Industry Canada use the term "personal/portable" rather than mobile, as it may allude to a TVWS device moving at vehicular speeds. Devices moving at high speeds would not be able to update through databases quickly enough to avoid interfering with other users. Also, high-speed mobile operations are particularly problematic for wireless microphones that may be operating in/near mobile TVWS devices.
Industry Canada agrees with the majority of respondents that the definitions of the categories of TVWS devices should be generally harmonized with those in the United States. Although this terminology would be different from that used in the United Kingdom, the proposed definitions make an explicit link to the "master" and "slave" nomenclature.
In response to concerns about the use of the term "mobile" in the proposed definitions, it should be noted that this term does not imply that vehicular operation will be permitted. Vehicular operation would be precluded in practice by the need to reconfirm available channels when a device is moved regardless of whether the term "mobile" is used in these definitions. Nomadic and transportable operations are permitted under this definition of mobile TVWS devices.
The final wording of these category definitions will be determined following the release of this decision during the development of the technical standard. This will allow for an opportunity for improvements to the originally proposed wording. In addition, this will ease future updates if required, and will ensure that these category definitions do not restrict the potential for future innovation.
Decision related to TVWS categories:
Industry Canada will generally harmonize with the U.S. definitions of TVWS categories, with the exact wording to be determined by Industry Canada through its established processes, including consultation with stakeholders.
7.2 Operating Channels
With some restrictions, the consultation proposed that TVWS devices be permitted to operate on available channels throughout the TV broadcasting bands below 698 MHz. In order to prevent harmful interference, TVWS devices would not be permitted to operate on TV channel 37, which is used by medical telemetry devices and radio astronomy operations at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, British Columbia.
The consultation also noted that TVWS devices in the United States are subject to additional restrictions on operating channels, depending on whether a fixed or mobile TVWS device is being used.Footnote 2
7.2.1 Summary of Comments
- Respondents generally agree with the proposal to broadly harmonize available operating channels for fixed and mobile TVWS devices with the United States, as well as the proposed operating channel restrictions.
- Some RABC members suggest that Industry Canada consider allowing the operation of mobile TVWS devices on any available channels, including below TV channel 21. In their opinion, the geo-location and database query approach will provide adequate interference protection without the need for additional restrictions. Other RABC members believe that mobile devices should not be permitted below channel 21.
- Motorola also requests that Industry Canada not restrict the use of mobile TVWS devices below TV channel 21. This rule was developed to protect public safety and commercial land mobile radio systems on TV channels 14 to 20, which only exist in the United States.
- The RABC and broadcasters recommend that channels 3 and 4 in which consumer electronic devices operate, along with channel 37 in which medical telemetry and radio astronomy operate, be explicitly identified in any future documents as prohibited channels for any form of TVWS devices in Canada due to significant risk of interference.
- Rogers comments that TVWS devices should not be permitted to operate on TV channels 2 to 20, 37 or 51. TVWS devices should be prohibited in channels 2 to 13 in particular because VHF TV receivers are more susceptible to interference from electronic devices than UHF TV receivers.
- Neul does not see a need to restrict access to channels according to device type and prefers the approach taken in the United Kingdom to allow use on output power levels, both in-band and out of band, to be determined dynamically on a case-by-case basis, rather than in a static manner through predefined channel restrictions.
- Shure feels that mobile TVWS devices should not be permitted to operate below channel 21, that there should be no fixed operation on channels adjacent to broadcast stations and that no operation of TVWS devices should be permitted on channel 37. Allowing only fixed TVWS operation on certain channels would ease sharing with LPA such as wireless microphones, as it would be easier to plan around the relatively static environment associated with fixed TVWS operation.
- Ericsson recommends that Industry Canada consider possible ways to mitigate or minimize the potential interference on channel 51 to avoid adjacent channel interference. Rogers proposes that licensed commercial mobile above TV channel 51 be protected from TVWS devices by limiting the power in channel 51 and adopting rules for minimum distances from commercial mobile base stations.
A majority of respondents support harmonization with U.S. rules, including a restriction that mobile TVWS devices only be allowed to operate on TV channel 21 and above. Although there are some comments that propose either greater or lesser restrictions, Industry Canada believes that the advantages of such harmonization by providing a common market for equipment with its resulting benefits for equipment cost and availability outweigh the stated concerns.
Industry Canada agrees with respondents that the heavy use of TV channels 3 and 4 by consumer electronic devices and the risk of harmful interference to those devices from TVWS devices warrant a restriction from operation on these channels, as the United States has also concluded. Radio astronomy observations on TV channel 37 are limited to a single location in Canada and could be protected through the TVWS databases. However, licence-exempt wireless medical telemetry operating on TV channel 37 is used throughout Canada and therefore also warrants a restriction on TVWS operation on this channel, similar to the restriction in the United States.
As the proposed transmitted power for TVWS will be much lower compared to that of the commercial mobile service, the likelihood of adjacent channel interference from TVWS devices will also be lower than the likelihood of interference from adjacent mobile systems. As such, Industry Canada will not restrict TVWS devices from using TV channel 51; however, technical measures for mitigation of adjacent band interference may be considered during the development of technical rules if sufficient technical justification is provided.
Decision to set operating channels:
Industry Canada will broadly harmonize with the U.S. rules regarding channels available to fixed and mobile TVWS devices. Detailed rules will be developed regarding available operating channels for different categories of TVWS devices using Industry Canada’s established processes, including consultation with stakeholders.
7.3 Protection of TV Broadcasting
TV broadcasting in Canada has transitioned from an analog to a digital signal format in CRTC-defined mandatory markets; however, there may be continued analog TV broadcasting operations outside these areas. For this reason, protection criteria for both analog and digital TV broadcasting were proposed.
The consultation paper noted that the United Kingdom has proposed a different approach for interference protection from that used in the United States. Rather than specify minimum separation distances as the U.S. has done, the United Kingdom has proposed that TVWS devices in the United Kingdom continuously adjust their transmitter power levels under database control to ensure that TV broadcast interference protection requirements are met. This approach allows for TVWS devices to access additional spectrum at the cost of a significant increase in computational and regulatory complexity.
Comments were sought on the interference protection criteria proposed for TV broadcasting operations to ensure the protection of over-the-air TV broadcasting services. Comments were also sought on whether provisions should be made for TVWS devices using power control to have additional flexibility in selecting frequencies, as in the United Kingdom.
7.3.1 Summary of Comments
Protection Criteria for TV Broadcasting
- All respondents agree with the need to protect broadcasting reception and that the proposed criteria would be adequate. The RABC notes that protection is needed for the full range of broadcasting system types, including full power stations, low-power stations, very low-power stations and receive stations (i.e. cable TV head-ends and TV translator receive sites).
- Rogers is also of the view that certain TV receivers, such as cable television head-ends, could be protected beyond the edge of a TV service contour by registering those receivers in the databases.
Power Control vs. Separation Distance
- Some respondents believe that the U.K. approach should be considered, as it could enable the development of a wider range of devices and applications. They also believe that the U.K. approach will enable access to more white space than the U.S. approach without increasing the risk of interference to broadcasting reception, and that the U.S. approach is too restrictive.
- Nokia notes that flexible power control will benefit TVWS devices in that it will allow operation in additional areas where reduced transmit power is required in order to prevent interference.
- Other respondents prefer the U.S. approach. For example, the RABC prefers commonality with the United States, even though power control may prove useful in the United Kingdom, where TV transmitters are much more tightly packed in order to serve a denser population. In their view, the currently wider geographic TV spacings employed in Canada may not require such measures. Some wireless manufacturers and research and development entities also recommend the harmonization of TVWS technical rules with the United States.
Although there is agreement on the need to protect TV broadcasting reception, opinions are divided on whether the U.S. or U.K. approach would be best. More respondents prefer the U.S. approach for reasons of harmonization and all agree that it would provide sufficient protection for TV broadcasting reception. However, there is agreement that flexible power control as in the U.K. approach has significant potential to improve spectral efficiency.
Industry Canada notes that, because of differences in TV broadcasting regulation, the United Kingdom’s flexible power control approach would require extensive technical work to be adapted for use in North America. For instance, North American TV coverage areas are specified based on a particular broadcast signal strength whereas in the United Kingdom, TV broadcast coverage areas are specified on a statistical basis taking into account the fact that the locations of all TV sets in the United Kingdom are known due to a legal requirement in these for TV sets to have a licence. For these reasons, the adoption of this approach in Canada would require extensive technical reworking that would likely result in significant delays in the availability of TVWS devices in this country.
Industry Canada will adopt protection criteria to protect the full range of broadcasting systems from harmful interference from TVWS devices as part of its technical rule development. This will include consideration of the possibility to register certain TV receiver stations, such as cable television head-ends, outside of the TV service contour.
In general, for reasons of harmonization and timing, the initial protection criteria will be based on broadcasting service coverage contours and defined separation distances that are harmonized with the United States. That said, Industry Canada will monitor developments in the United Kingdom and will consider updates to its technical rules once experience is gained with the United Kingdom’s flexible power control approach. In any case, North American harmonization will remain an important goal.
Decision related to the interference protection criteria for TV broadcasting operations:
Detailed interference protection criteria, based on the full range of analog and digital TV transmitters, will be developed in accordance with Industry Canada’s established processes, including consultation with stakeholders.
7.4 Protection of Radio Astronomy
In the consultation paper, Industry Canada proposes to adopt provisions to protect radio astronomy operations from the potential for interference from TVWS devices. In Canada, the only location at which radio astronomy observations are made is the DRAO in Penticton, British Columbia.
7.4.1 Summary of Comments
The comments received unanimously agree that the radio astronomy service should be protected from harmful interference caused by TVWS devices.
Industry Canada agrees with the need to protect radio astronomy observations at DRAO, which provide an important contribution to scientific research in Canada. Although TVWS devices will be restricted from operating on TV channel 37, on which most of these observations are made, the high level of sensitivity of the receivers used at DRAO makes them extremely sensitive to radio emissions throughout the TV bands, and not just on TV channel 37. Therefore, in line with past decisions, Industry Canada will adopt provisions through its technical rules for the protection of observations at the DRAO site from TVWS devices operating in nearby channels.
Decision related to the protection of radio astronomy:
Detailed provisions to protect radio astronomy observations made by the DRAO in Penticton, British Columbia, will be developed in accordance with Industry Canada’s established process, including consultation with stakeholders.
7.5 Technical Parameters
Industry Canada sought comments on the technical parameters for TVWS devices, noting that these parameters would be developed in more detail following future decisions.
7.5.1 Summary of Comments
- Most respondents believe that technical parameters should generally be harmonized with those in the United States; however, some respondents suggest that harmonization with the United Kingdom would be preferable. Some additional TVWS proponents suggest that Industry Canada should be technology neutral.
- Broadcasters propose that TVWS fixed device transmitter power output should be limited to 1 watt maximum.
- The Institute of Electrical and Electronics Engineers 802 Local Area Network / Metropolitan Area Network Standards Committee believes that the location accuracy should be verified during certification of a TVWS device.
Harmonizing technical parameters with those of the United States will promote a common market for TVWS equipment, with resulting benefits for equipment cost and availability. For this reason, Industry Canada will broadly harmonize its technical rules for TVWS devices with those of the United States, including areas such as transmitter power limits, location accuracy, minimum frequency of database checks and cessation of operation rules if a TVWS device cannot make contact with an approved database. As part of the technical rule development process, Industry Canada will consider proposals for technical variations should sufficient justification be provided and on the condition that broad harmonization is maintained. As is normal practice, any technical provisions that are specified in Industry Canada’s rules will be subject to testing and certification.
It is expected that TVWS device technology will continue to improve. As such, Industry Canada expects to revisit and update the technical rules for TVWS devices as needed to reflect these improvements.
Decision related to technical parameters:
Detailed technical rules will be established using Industry Canada’s established processes, including consultation with stakeholders.
7.6 Out-of-Band Emissions
Comments were sought on appropriate limits for out-of-band radio emissions of TVWS devices. This included comments on whether Industry Canada should include the use of flexible out-of-band emission masks similar to those expected to be implemented in the United Kingdom, or if it would be better for Canada to harmonize with the U.S. approach by specifying a fixed emission mask.
7.6.1 Summary of Comments
- Opinions are divided with regard to the approach on the out-of-band emissions. Some respondents prefer the United Kingdom’s adaptable approach and others prefer the U.S. approach. Most TVWS proponents and Axia NetMedia note that the United Kingdom’s approach provides additional flexibility; however, they acknowledge that the registration databases could support either type of approach.
- Shure comments that wireless microphones have proved to be more susceptible than TV receivers to the out-of-band emissions generated by first adjacent channel TVWS devices, and relaxing the mask would therefore be unacceptable. Along with Shure, Rogers and Motorola believe that deviating from the U.S. approach would stymie the development of TVWS devices and recommended harmonization of the TVWS technical rules with the United States.
Comments are evenly split between the U.S. and U.K. approaches as to which would be best in terms of harmonization, interference protection and cost implications. All respondents agree that the U.S. approach could be implemented and would provide adequate interference protection for other radio services. However, many respondents also believe that this mask might be unduly restrictive and that more flexibility could be permitted without an undue increase in interference risk through the inclusion of compensatory measures in the database protection algorithms.
Industry Canada notes that concerns have been expressed on whether the United Kingdom’s approach could be implemented without increasing the risk of interference to adjacent channel systems.
Industry Canada will specify criteria for out-of-band emissions as part of its development of technical rules. For reasons of harmonization and interference risk, the initial emission masks will be harmonized with U.S. rules. Once again, Industry Canada will continue to monitor developments in the United Kingdom and elsewhere, and may consider updates to its technical rules once experience is gained showing that there is no increased interference risk due to the United Kingdom’s use of multiple emission masks. In any case, North American harmonization will remain an important goal.
Decision related to the out-of-band emissions:
Industry Canada will initially harmonize its out-of-band emission masks and adjacent frequency protection criteria with the United States. The detailed technical standards will be developed in accordance with Industry Canada’s established processes, including consulting with stakeholders.
7.7 Cross-border Protection
The use of the broadcasting spectrum is covered by the Agreement Between the Government of Canada and the Government of the United States of America Relating to the TV Broadcasting Service and the Associated Working Arrangement, the Letter of Understanding, which covers the areas within 400 km of the border, and the Interim Agreement Between Canada and the United States Concerning Digital Television (DTV). The Letter of Understanding does not deal with non-broadcasting system use of the broadcast spectrum. Regardless, non-broadcasting use within 400 km of the Canada-United States border must be on a no-protection, no-interference basis with respect to broadcast services in both Canada and the United States. As well, Industry Canada currently enforces a mandatory 121 km border distance within which RRBS stations are not permitted to operate until such time as a new bilateral agreement is reached.
Comments were sought on Industry Canada’s proposal to protect U.S. stations operating near the Canada-United States border by including these stations in the Canadian TVWS databases, thereby ensuring the protection of these stations to the same level as stations in Canada.
7.7.1 Summary of Comments
- Comments received support Industry Canada’s proposal to use the same protection criteria that will be applied in Canada, which will require Canadian TVWS devices to protect active U.S. broadcasting stations within the United States.
- Shure and RIM both recommend that Industry Canada work with the United States to ensure that TVWS devices near the Canada-United States border are coordinated with LPA and other incumbent services requiring appropriate protection from interference from TVWS devices radiating across the border.
- Some broadcasters agree that the bilateral protection measures mentioned in the consultation should suffice until such time as there is a need to reopen existing agreements or create new ones covering specific unlicensed uses in both countries, as TVWS users will receive equal treatment on both sides of the border.
- Rogers notes that if Canadian TVWS device rules are more stringent than the U.S. rules and the databases are interconnected, then U.S. licensees will be protected adequately.
There were no objections to Industry Canada’s proposal for the protection of U.S. TV broadcasting reception in the vicinity of the Canada-United States border. The proposed measures mirror current provisions in the United States for the protection of Canadian TV reception near the border. There is no need to provide protection to TV allotments that are not currently in use in the other country, as the database update process will automatically provide this protection as new stations are brought on the air in the other country.
As per its normal practice, Industry Canada will continue to work with the U.S. Federal Communications Commission (FCC) to implement cross-border protection measures for TV broadcasting reception, LPA and RRBS stations. To the extent possible, Industry Canada will work with the FCC and stakeholders to encourage the development of measures to simplify operation of all services using TV broadcasting spectrum in the border area, for example, through the development of common registration processes.
Decision related to cross-border protection:
Industry Canada will require Canadian TVWS devices to protect active U.S. broadcasting operations based on the same protection criteria as will be applied to broadcasting operations within Canada.
8. Remote Rural Broadband Systems
Remote rural broadband systems (RRBS) provide wireless service in remote rural communities in Canada, using TV channels that are unallotted and unassigned. Unlike TVWS devices, these systems are technically evaluated by Industry Canada before they can receive a licence, in order to prevent harmful interference to other spectrum users, in particular, TV broadcasters. RRBS are licensed on a no-protection, no-interference basis in relation to the TV broadcasting service, and must not constrain the provision of existing or future broadcasting services.
The technical rules for RRBS equipment provide for higher transmitter power levels than for TVWS devices. In addition, no spectrum sensing or database access is required. Protection to other radio services from harmful interference is provided through departmental evaluation during the licensing process. Because of the constraints of the evaluation process, RRBS are limited to fixed station operation only.
Comments were sought on the potential for improvements to the framework for RRBS, including the possibility of phasing out licensed RRBS in favour of licence-exempt TVWS devices, with existing deployed RRBS being grandfathered. The consultation proposed that if this phasing out were to occur, TVWS devices could be permitted under database control to use higher power levels when in remote rural areas in order to prevent a gap in capability between the new licence-exempt TVWS devices and the currently licensed RRBS in those locations.
8.1 Summary of Comments
- TVWS proponents have no concerns about including RRBS in their databases so that they can be protected from harmful interference.
- The WRAN Alliance supports the idea of providing grandfather protection to deployed RRBS in Canada, and maintaining their licensed status with their operation registered in the database service to assure protection from interference from licence-exempt devices. The WRAN Alliance does not believe that RRBS should be phased out, but that new RRBS applications should be granted to facilitate deployment of broadband access in underserved areas.
- TELUS believes that RRBS seem to already address the needs that TVWS devices are proposing, and therefore encourages Industry Canada to take a "wait-and-see" approach with respect to the introduction of TVWS devices until a proof of concept is demonstrated and there is a viable commercial rollout, while continuing to license RRBS in the meantime.
- Shure is concerned that if higher powered TVWS devices are permitted as an alternative to RRBS, they may interfere with wireless microphones at a range of many kilometres. Shure comments that if higher power levels are needed in rural areas, it would be preferable that this be done in a licensed manner as currently done with RRBS.
- No comments were received from RRBS operators; however, Axia NetMedia believes that the status of RRBS should not change and that Industry Canada should continue to issue and renew RRBS licences under the current rules.
The consultation paper proposed to gradually phase out RRBS in the belief that TVWS devices, which are expected to be built for a mass market, would become a less expensive alternative for providing broadband connectivity in remote rural areas and that this would make up for the loss of certainty associated with the current licensing process for RRBS.
Many respondents to the consultation do not agree with this conclusion and argue persuasively regarding the continued importance of RRBS and that RRBS could successfully operate in parallel with TVWS devices. Industry Canada will therefore continue to issue and renew licences for RRBS for the time being. Industry Canada may revisit this decision if there are changes in the future to available TV broadcast spectrum below 698 MHz.
Incumbent licensees of RRBS will be protected from harmful interference caused by TVWS devices, and Industry Canada will adopt protection criteria for RRBS from TVWS devices by using existing RRBS-to-RRBS protection criteria as a starting point for discussion.
Decision related to the potential improvements to the framework for RRBS:
Industry Canada will continue to license RRBS.
Protection criteria will be determined through Industry Canada’s established processes, including consultation with stakeholders.
- Footnote 2
For instance, in the United States, mobile white space devices are limited to operating only on available channels above 512 MHz (i.e. TV channels 21-36 and 38-51) and operation of fixed white space devices may not be permitted on TV channels 3 and 4 (band 60-72 MHz) given that those channels are heavily used by consumer electronic devices.
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