Decisions on a Band Plan for Broadband Radio Service (BRS) and Consultation on a Policy and Technical Framework to License Spectrum in the Band 2500-2690 MHz
Part A – Decisions on Band Plan and Mapping of Incumbents to the New Band Plan (continued)
1. Band Plan (continued)
1.3 Realigned Spectrum Blocks (continued)
TELUS, in its comments and reply comments, objected to the amount of returned spectrum set out in DGSO-001-10. TELUS stated that "the 2006 Policy [Decision] precisely specifies the return of 50% of the FDD spectrum created via the mobile conversion and adoption of the FDD/TDD band plan." As well, TELUS made the following observations and proposals:
|Translation||Description||Incumbent retained FDD||Returned FDD|
|Baseline||2006 Policy/US Band plan||66 MHz (6 of 12 pairs)||66 MHz|
|1||Pro Rata||70 MHz (7 of 14 pairs)||70 MHz|
|2||DGSO-001-10 Proposed||80 MHz (8 of 14 pairs)||60 MHz|
|3||TELUS Proposed||60 MHz (6 of 14 pairs)||80 MHz|
TELUS argued that changing the 2006 Policy Decision with respect to the amount of returned spectrum would result in providing incumbents with a "21% increase in retained incumbent FDD spectrum (from 33 MHz to 40 MHz)," which "comes at the expense of band entrants and tax payers and is not in keeping with the in-force policy in the band." As an alternative, TELUS recommended that the Department "give band entrants as a group the opportunity to bid on 21% more FDD spectrum at auction and reduce the incumbent's retained FDD spectrum by 9%" (See Translation 3 in Table 2 above). MTS Allstream and EastLink, in reply comments, supported TELUS' proposal. EastLink also recommended that the Department reconsider the spectrum return and reallocation in light of the proposed harmonization with the international band plan. SaskTel objected to TELUS' proposal, stating that it was narrowly focused on FDD spectrum and failed to take into account the entire 2500 MHz spectrum. Inukshuk also objected to TELUS' proposal and recommended that Industry Canada adopt Inukshuk's alternate incumbent mapping proposal instead (to be discussed in Section 1.4 below).
The 2006 Policy Decision indicated that the Department would harmonize the Canadian band plan to be compatible with the U.S. band plan. Similar to the licensing process in the United States, Canadian MCS and MDS licences were issued based on a technology-flexible band plan in which no distinction was made between FDD or TDD operations. Licensees were free to deploy either TDD or FDD within their authorized licensed spectrum. Furthermore, licences were issued on an unpaired basis. In accordance with the 2006 Policy Decision, calculation of the amount of returned spectrum was based on the amount of originally authorized spectrum, and not based on whether the spectrum is paired.
As shown in Figure 4 above, if the returned spectrum were to have remained as the bands 2535–2568 MHz and 2657–2690 MHz (as per the 2006 Policy Decision), the incumbents would have retained 2 x 37 MHz (2500–2535 MHz and 2568–2570 MHz; and 2620–2657 MHz) of paired spectrum under the ITU band plan. In comparison, the proposal to amend the returned spectrum to 2540–2570 MHz and 2660–2690 MHz (as per DGSO-001-10) would provide the incumbents with 2 × 40 MHz (2500–2540 MHz and 2620–2660 MHz) of paired spectrum. This would represent an increase in paired spectrum to incumbents of 8%, and not 21%.
The Department notes that the 2006 Policy Decision has been in place for more than four years and that it has provided regulatory guidance to incumbents and other potential band entrants on their operational and business plans. Thus, major changes to the implementation of the 2006 Policy Decision are not appropriate at this point and would fundamentally undermine such business plans based on the Department's previous determinations (i.e. the return to the Department of roughly one third of the spectrum).
Therefore, consistent with the 2006 Policy Decision, the Department maintains that it is appropriate to require that returned spectrum constitute 2 × 30 MHz of spectrum (i.e. 2540–2570 MHz and 2660–2690 MHz) as set out in DGSO-001-10.
1.4 Alternate Incumbent Mapping Proposals
Inukshuk, in its comments, stated that the 2006 Policy Decision did not provide incumbents with paired blocks of spectrum and thus presented incumbents with the prospect of being stranded with only one of two paired blocks in the FDD portion of the band. Inukshuk submitted that the 2006 Policy Decision has been overtaken by technological developments and that the Department's proposal for mapping incumbents has been unnecessarily constrained by that Decision. Inukshuk contended that, by limiting the amount of paired spectrum which incumbent licensees may retain, the Decision forced incumbents to hold both paired and unpaired spectrum. Inukshuk also stated that the 2006 Policy Decision arbitrarily and unreasonably limits the amount of contiguous paired spectrum that incumbents may retain, thereby impeding the maximal spectral efficiency and data speeds that will be required to satisfy the demand for mobile broadband services. Inukshuk proposed alternate incumbent mapping proposals, which would result in additional contiguous spectrum in the paired spectrum for incumbents under the new BRS band plan. More specifically, Inukshuk recommended that, in areas where it holds only MCS or only MDS licences, it would obtain new BRS licences based on 30 + 30 MHz of paired contiguous spectrum (2530–2560 MHz paired with 2650–2680 MHz) with no unpaired spectrum. In areas where Inukshuk holds both MCS and MDS licences, it recommended that it should obtain new BRS licences based on 60 + 60 MHz of contiguous spectrum (2500–2560 MHz and 2620–2680 MHz) with no unpaired spectrum. Inukshuk submitted that such an exchange would provide it with an opportunity to acquire additional spectrum in order to satisfy future demand for mobile broadband services and to achieve larger spectral efficiencies, faster data speeds and more reliable service levels. In reply comments, MTS Allstream and TELUS objected to Inukshuk's proposal, stating that it is inconsistent with the Department's goal of fostering competition and with the objective of maximizing FDD availability.
Pacomm recommended that Industry Canada "shift the MCS paired spectrum to the top of the FDD uplink and downlink bands, to facilitate coexistence between MCS FDD uplinks and MCS unpaired bands and possible elimination of lower TDD guard or restricted band." Similarly, EastLink proposed that the Department "allocate the upper part of the FDD paired spectrum to the same licensee that would operate in the TDD part of the band." EastLink also indicated that "the spectrum returned by the incumbents should be reallocated as largely TDD spectrum with paired FDD from the upper portion of the band. This would allow the incumbents to minimize the impact on their systems, and on consumers, while freeing up the maximum amount of FDD spectrum for the auction."
SSI claimed that if the new band plan required SSI to operate in FDD rather than TDD, "its operations would be crippled." SSI stated that it operates in 54 of the most remote communities in Canada and that a change in band plan would require significant changes to its wireless equipment in these areas. SSI therefore urged the Department to make its band plan determination sufficiently flexible to accommodate such constraints.
Industry Canada recognizes that permitting incumbents to choose which portions of the spectrum the Minister should authorize for BRS licences would provide them with the flexibility to choose the spectrum that is best suited for their needs on an individual basis. However, the Department notes that, in allowing such flexibility, the 2500 MHz band could be fragmented on a nationwide basis, potentially affecting the value of all authorizations within the band. Apart from the necessary amendment to align with the ITU band plan, the specific frequency range of spectrum to be treated as returned spectrum has been known since 2006. This has provided regulatory guidance to incumbents, as well as potential new entrants, as to the future availability of spectrum. The Department therefore considers that it is not beneficial to consider an alternative set of licensed versus returned spectrum at this point. Therefore, the returned spectrum will be 2540–2570 MHz and 2660–2690 MHz, as indicated in DGSO-001-10.
1.5 Operation of Non-FDD Systems in Paired Blocks
In the event that the ITU band plan was adopted, the Department sought comments on whether the operation of TDD systems should be permitted in the paired portion of the band plan (2500–2570 MHz and 2620–2690 MHz) and, if so, under what conditions.
GSMA, MTS Allstream, QMI, and SaskTel were of the view that permitting TDD systems in the paired spectrum blocks would lead to significant interference. GSMA, RABC, SaskTel and TELUS stated that interference is very likely to happen both with base stations and terminals. These parties stated that TDD systems operating in the paired spectrum blocks would generate interference to FDD systems operating in the same geographical area in the adjacent FDD blocks, as well as to FDD systems operating in the same frequency block (or in a frequency block overlapping with the block of the TDD system) and in an adjacent geographical area. SaskTel also indicated that, in some cases, mitigation measures would be very costly to implement and that there would be cases where interference would be extremely difficult or even impossible to eliminate. Inukshuk, Ericsson, MTS Allstream and QMI pointed out that permitting TDD operation in the paired spectrum would require the use of additional guardbands, resulting in an inefficient use of the spectrum.
SaskTel stated that operation of TDD and FDD systems in the same or adjacent spectrum blocks in different geographical areas would place future restrictions on the geographic expansion of the networks for both FDD and TDD operators. RABC and TELUS noted that permitting TDD operation in paired spectrum would especially affect global roaming for portable/mobile equipment and would result in the loss of most of the benefits of adopting the ITU band plan. Further, 3G Americas maintained that allocation of separate frequency ranges for use by FDD and TDD would be more efficient given that guardbands would not be required. 3G Americas added that the equipment currently in development for this band is based on globally recognized standards and, therefore, that an allocation reflecting a globally harmonized recommendation would enable rapid, affordable deployment of infrastructure, devices and innovative applications within Canada. MTS Allstream was of the view that the unpaired spectrum block should be more than sufficient to support any existing and anticipated TDD system demand.
As such, the majority of respondents (3G Americas, EastLink, Ericsson, GSMA, Inukshuk, MTS Allstream, QMI, RABC, SaskTel, TELUS and YourLink) submitted that new TDD operation should not be permitted in the paired spectrum blocks. Inukshuk, RABC, and TELUS added that continued TDD operation could be permitted in the paired spectrum blocks on a transitional basis only (i.e. during the migration period to the new band plan). RABC and TELUS further argued that, in the event where an incumbent would need to operate TDD systems in the paired spectrum block for an extended period of time, the incumbent should provide the necessary guardbands to avoid interference.
Inukshuk and YourLink argued that incumbent TDD operators should not be required to migrate their systems unless and until other BRS licensees require access to that spectrum. In particular, it was submitted that TDD systems in remote areas should be permitted to continue to operate until new FDD systems are licensed in those areas.
Intel maintained that TDD systems should be permitted to operate in the paired spectrum blocks. Intel argued that this would allow the most flexibility for technological innovation and permit operators to deploy the technology that best suits their customers' needs. Similarly, Pacomm recommended that the Department permit TDD operation in the paired spectrum and stated that some TDD applications may be able to coexist with FDD in the same spectrum (e.g. indoor underlays). In other cases, however, there would be inefficiency in using FDD spectrum for TDD operation due to the requirement for guardbands.
In light of its position as a service provider in remote communities in the Northwest Territories and Nunavut, SSI argued that the continued operation of its TDD systems should be permitted. SSI stated that forced conversion to FDD would be disruptive to its ability to provide service to its customers in 54 of the most remote communities in Canada. As SSI does not intend to install FDD equipment for a considerable period of time, it therefore does not anticipate having to manage the coexistence of its own FDD/TDD operations. Any interference would arise as a result of coexistence with new operators, in which case a guardband may be necessary. In some cases, other mitigation measures could be employed.
In DGSO-001-10, it was noted that the Department created technology-neutral rules in the Personal Communications Services (PCS) and Advanced Wireless Services (AWS) bands, which permitted the operation of TDD systems in paired bands. Any such TDD systems must operate within the technical rules for FDD and must avoid creating any interference to FDD systems. To date, no TDD systems have been deployed in either the PCS or AWS bands.
As noted in DGSO-001-10, FDD and TDD radio systems are not generally interoperable. In the FDD uplink band (2500–2570 MHz), without any interference mitigating techniques, TDD base station to FDD base station interference is high for both co-located and in proximity scenarios. There are a number of actions that can be taken in order to limit the interference between base stations: guardbands, additional front-end filters, restricted channels, deployment restrictions and special site engineering (in the case of co-siting). The Department notes that many of the measures would need to be taken in both FDD and TDD operators' networks in order to be meaningful (e.g. it would be necessary to apply additional front-end filters to both the FDD and TDD systems to suppress adjacent channel interference). Also, the use of guardbands, where appropriate, should not be considered in isolation, but in conjunction with other solutions such as additional front-end filters. Adding filters, however, to the base stations would of course increase the network complexity, partly due to the additional hardware and partly due to installation and maintenance. This would affect quality and coverage of the system where the filters are applied. For co-siting, one may use vertical antenna separation together with front-end filters (applied to both base stations involved) to decrease the interference. This will give sufficiently low interference for the second adjacent channel, but not for the first. The interference mitigating techniques suggested above for the adjacent channel scenario (e.g. filtering, guardbands) are not all applicable to the co-channel case, which may lead to increased separation distances for co-channel situations.
In the FDD downlink band (2620–2690 MHz), TDD terminal station to FDD terminal station adjacent-channel interference in the same geographic area can be severe regardless of frequency separation. Saturation, or "blocking," where a terminal station becomes overloaded by the high power levels of the adjacent channel interferers, would prevent the receiver from processing the wanted signal. In this case, an FDD terminal station (on any FDD channel across the entire downlink band) will typically receive interference if within approximately 10 metres (assuming other losses or physical blockage) of a transmitting TDD terminal station operating in any particular channel within the downlink band. The FDD terminal station is also susceptible to radiation spectral leakage, as the pass-band of the FDD front-end filter would nominally cover the frequency range 2620–2690 MHz in order to allow the terminal station to receive signal from base stations transmitting in any of the paired (FDD) downlink blocks. In addition to the preceding effects, it is also possible for signals received at adjacent channels to result in interference through intermodulation (IM) products caused by non-linear behaviour at the FDD receiver. The IM products can be a significant source of co-channel interference when the FDD receiver is exposed to multiple unattenuated adjacent-channel TDD interferers.
The Department also notes that some incumbent operators have already deployed non-FDD systems in the paired blocks. Some of these operations are in rural or remote areas where the probability of interference with other systems is relatively low. The comments received generally supported the continued operation of such incumbent systems provided that they do not cause interference to new BRS systems. There was general agreement that incumbents should be displaced only if necessary and, even then, should be given sufficient notice before being required to do so. MTS Allstream was of the view that Industry Canada should give incumbents as much time as is reasonably necessary to migrate to the new band plan. TELUS, Motorola and RABC stated that incumbents should be given a period of 12 months starting from the issuance of a displacement notice by Industry Canada. The Department should issue displacement notices after having reviewed and approved displacement requests from BRS licensees. Inukshuk provided similar comments, except it stated that incumbents should be given a minimum period of 12 months starting from the issuance of a displacement notice by the Department. EastLink and QMI preferred using the auction date as a reference point. EastLink urged Industry Canada to set a hard deadline for transition based on the auction date, whereas QMI proposed that migration be completed no later than 12 months before the beginning of the auction. EastLink further indicated that a period of less than 12–36 months from the date of displacement notice would be preferable.
It is the general policy of Industry Canada to effect the displacement of frequency assignments only when and where required, so as to minimize disruption. The Department recognizes the significance of providing reasonable notice to inform spectrum users of any conditions or circumstances that might result in the displacement of services. In addition, the Department recognizes the challenges associated with the physical migration of existing systems and their impact on users, particularly in northern areas of Canada, i.e. Yukon, the Northwest Territories and Nunavut, where a longer migration time may be necessary. The Department also recognizes that FDD operation could potentially be affected by non-FDD operation in the paired blocks.
Therefore, the Department has decided that incumbents may continue to operate their non-FDD systems in their existing licensed bands within the paired spectrum blocks subject to the decisions included in Section 1.9. Accordingly, incumbent non-FDD operators are herewith advised to take the above into consideration and, if necessary, begin planning and implementing their migration plan in a timely manner.
In accordance with the band plan adopted in this decision, it is intended that FDD systems are to be deployed within the paired spectrum blocks.
New non-FDD systems may be deployed within the paired spectrum blocks in exceptional cases subject to the policy provisions contained in this paper. As discussed previously, it is noted that a non-FDD operation could potentially affect not only FDD systems operating in the same area in the same frequency channel, but also frequency channels anywhere in the paired blocks in the same or nearby areas in which the non-FDD system operates. Even after a non-FDD system is deployed, it could be subject to future displacement or termination due to the requirement of any existing or future FDD operators. Non-FDD operators are advised to take the above into consideration should they decide to deploy a non-FDD system in the paired spectrum blocks.
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