17 December Manager, Emerging Networks DGSO Industry Canada 300 Slater Street Ottawa, Ontario K1A 0C8. Dear Sir or Madam:

Transcription

1 17 December 2012 Manager, Emerging Networks DGSO Industry Canada 300 Slater Street Ottawa, Ontario K1A 0C8 Dear Sir or Madam: Re Canada Gazette, Part I, Vol. 146, no. 42, p. 2942, October 20, 2012 Notice No. DGSO Consultation on Renewal Process for 2300 MHz and 3500 MHz Licences I. Introduction 1. Ciel Satellite Limited Partnership ( Ciel ) is pleased to offer the following comments in connection with Industry Canada s Consultation on Renewal Process for 2300 MHz and 3500 MHz Licences (DGSO ) (the Consultation ). 2. Ciel is a licensed Canadian satellite operator. Ciel is majority-owned by SES S.A. ( SES ), a global satellite operator with a fleet of more than 50 geostationary satellites that collectively reaches 99% of the world s population. Ciel has operated the Ciel-2 BSS satellite at the Canadian 129 W geostationary orbital position since 2008 and currently provides broadcasting-satellite services throughout the North American market. Ciel also holds approvals in principle from Industry Canada to develop seven additional Canadian BSS and FSS frequency assignments. 3. The matters raised in the Consultation are of concern to both Ciel and SES due to the impact the decisions made in this Consultation could have on the future integrity of the Fixed-Satellite Service (FSS) in Canada. Recent studies have identified a Ciel Satellite LP Suite 410, 116 Lisgar Street, Ottawa, Ontario, Canada K2P 2K1 tel. (613)

2 DGSO December 2012 Page 2 significant potential for interference into the FSS in the band MHz (Standard C-band space-to-earth) arising from Fixed Service WiMAX operations in the 3500 MHz band. Moreover, examples of such interference have been reported in other jurisdictions. Although there have been no publicised cases of such interference occurring yet in Canada (which is perhaps not surprising given the limited roll-out of the 3500 MHz licences) Ciel nonetheless urges the Department to proceed with caution in considering the renewal and future implementation of these licences. II. Context 4. The Department notes in paragraph 45 of the Consultation that the Canadian Table of Frequency Allocations identifies the Radiolocation, Mobile, Fixed and Fixed-Satellite Services as having primary allocations or co-primary allocations, or both, in various sub-ranges of the band MHz. It is important to stress at the outset that the FSS in the Table has a co-primary allocation with only the Fixed Service in the band MHz. The MHz band is the space-to-earth segment of the Standard C-Band, which is used extensively throughout Canada by satellite operators and customers. In Canada (as is the case in the United States and Brazil) there has been no allocation to the mobile service in the Standard C-band in the National frequency allocation table. 5. The Standard C-band was allocated to and has been in continuous use by the Canadian satellite industry since the first satellite networks were deployed more than 40 years ago. Sharing between the Fixed and Fixed-Satellite Services has been common over that period and has proven in most cases to be problem-free. However, in recent years, interference issues have started to appear in some jurisdictions as use of the 3500 MHz band for WiMAX applications has increased. 6. The growing problem of interference into the C-band FSS from 3500 MHz band WiMAX applications was studied and documented in a recent white paper, 1 a copy of 1 J. Christensen, P. Hovstad, and R. Zhang, Interference from Broadband Wireless Access into Satellite C-Band FSS Applications. In IEEE Globecom 2012, Anaheim, California, 3-7 December 2012.

3 DGSO December 2012 Page 3 which is attached to this submission as Appendix A. The authors of the paper examine the potential for interference from broadband wireless access systems into the C-Band FSS, and conclude, inter alia, that: Terrestrial signals in any part of the GHz band therefore can saturate satellite LNA s and LNB s or bring them into non-linear operation and thus block reception of signals anywhere in the entire GHz band, even if the terrestrial signal is not overlapping with the FSS signal. (emphasis added) 2 7. Cases of interference have been reported in many countries which have authorised fixed or mobile services in parts of the C-band shared with or adjacent to parts of the C-band used for Fixed-Satellite Service. Public reports of interference have been recorded in Bolivia, Fiji and Indonesia, and field trials in Hong Kong have confirmed this interference. At the beginning of 2012, the British Broadcasting Corporation (BBC) confirmed that FSS earth stations operating in the C-band and used for their international satellite distribution network of radio and TV content had been affected by harmful interference in the following countries: D.R. of the Congo, Gabon, Guinea, Morocco, Nigeria, Tanzania, Uganda, Burkina Faso, Burundi, Rwanda, Pakistan, Cambodia, Trinidad, South Sudan and Jamaica. Furthermore, Bangladeshi broadcasting, cable and satellite TV operators, in co-ordination with the international satellite communications industry, recently called for the Government of Bangladesh to take rapid action to halt the disruption of TV services in the MHz band suffered by millions of citizens due to the operation of WiMAX services in the 3.5 GHz band. 8. Ciel is also concerned about references in the Consultation to potential future modifications to the current allocations in the Canadian Table of Frequency Allocations to harmonize with those of other countries. Although it is true, as the Department notes in the Consultation, that other jurisdictions are considering the use of spectrum up to 3800 MHz to support the introduction of new mobile services, it should be clear that such an approach is not an option for Canada. The exclusion of 2 Ibid, p. 3

4 DGSO December 2012 Page 4 a mobile allocation in the Standard C-band has made it possible for Canada to avoid the interference issues that have been encountered in many other jurisdictions, and has allowed Canadian satellite operators to build robust Standard C-band networks in urban and other highly-populated areas, as well as in rural and less denselypopulated areas. This is a policy approach that has worked well and should continue. Further, it should be recognized that the Extended C-band (3400 MHz 3700 MHz) is heavily used for critical satellite services in many countries outside of Canada, in particular in many developing countries, and that this band is becoming particularly vulnerable to encroachment from rapidly growing terrestrial services. 9. The purpose of raising these concerns in the context of the present Consultation is twofold: to ensure that there is a recognition by Canada in the licence renewal process for the 3500 MHz licences that the potential exists for these operations to create harmful interference into the Standard C-band; and to emphasize the importance of maintaining and protecting existing FSS operations in this band. III. Specific Comments 10. As a satellite operator, Ciel is not in a position to offer detailed comments concerning the commercial or operational aspects of the two renewal options proposed in the Consultation. However, Ciel does wish to provide some specific suggestions with respect to the proposed length and conditions of the proposed renewal terms, in light of the concerns identified above. 11. If the Department elects to renew the licences in the 3500 MHz band, Ciel would recommend that Industry Canada adopt Option 1. The licence terms should be extended to a fixed date for all licensees, to provide greater clarity and simplicity in dealing with future renewals or changes to the band plan. However, Ciel suggests that December 2016, rather than December 2017, would be a more appropriate extension date. One of the key inputs to the Department s assessment of the band plan and future renewals of the licences will be the decisions of WRC-15 concerning, among other things, future mobile allocations, and the Department should maintain as much flexibility as possible to address those decisions in a timely manner.

5 DGSO December 2012 Page Given the minimal deployment to date that has occurred under the existing licences, the Department should also ensure that it retains the maximum flexibility to renew, reassign, or cancel existing licences as may be appropriate on the next renewal date (i.e. December 2016). The associated deployment requirements should be assessed with this concern in mind. 13. Finally, as noted above, Ciel urges Industry Canada to always be mindful of the negative impact that future modifications to the allocations in the Canadian Table of Frequency Allocations in the band MHz may have on the Fixed-Satellite Service. Although Ciel recognizes that the present Consultation does not make any specific proposal for modifications to the Table at this time, the Consultation does refer in a number of instances to future consideration of changes to the band plan and an intention to modify current allocations in the Table to harmonize with those of other countries. It should be made clear to all stakeholders that those modifications will not, under any circumstances, encroach on the Standard C-band in Canada. All of which is respectfully submitted. Sincerely, Scott Gibson Vice President & General Counsel Ciel Satellite Limited Partnership encl.

6 Appendix A Interference from Broadband Wireless Access into Satellite C-Band FSS Applications Jorn Christensen, Per Hovstad, Rui Zhang December 2012

7 Interference from Broadband Wireless Access into Satellite C-Band FSS Applications Jorn Christensen 1, Per Hovstad 2, Rui Zhang 2 1 CASBAA, Hong Kong, 2 AsiaSat, Hong Kong Abstract In many countries terrestrial broadband wireless access (BWA) in the 3.5 GHz band are presently causing harmful interference into C-band satellite links. This interference can be caused even if there is a separation in frequency between the BWA and the C-band fixed-satellite service (FSS) link. This paper will examine the three types of interference: cochannel, adjacent channel and saturation of LNB. In addition, the paper will briefly outline the regulatory decisions of the World Radiocommunication Conferences in 2007 (WRC-07) which adopted footnotes that allowed such operation in some countries and take note that C-band will be under further attack at the upcoming WRC-15. Keywords-broadband wireless access; interference; satellite C- band; fixed-satellite service I. INTRODUCTION In many parts of Asia and Africa with heavy rain C-band satellite links are depended upon for many telecom applications including connection to the Internet backbone. Unlike the Ku- and Ka-bands there is virtually no rain attenuation and hence no outage in the C-band even during very heavy rain. However, in many countries terrestrial broadband wireless access (BWA) applications in the 3.5 GHz band are presently causing harmful interference into C-band satellite links. This interference can be caused even if there is a separation in frequency between the BWA and the C-band fixed-satellite service (FSS) link. This paper will examine the three types of interference: cochannel, adjacent channel and saturation of LNB. The paper will give calculations of the relative strength of the terrestrial and satellite signals and show why this type of interference is so serious. The paper will also briefly summarize the regulatory decisions of the World Radiocommunication Conferences in 2007 (WRC-07) which adopted footnotes that allowed such operation in some countries. Finally, the countries that rely on C-band satellite communications should take note that the C- band will be under further attack at the upcoming WRC-15. At this conference terrestrial interests will be looking for more spectrum for International Mobile Telecommunication (IMT) and 4G terrestrial applications and the C-band has not been excluded from consideration.. II. TECHNICAL STUDY This section presents the analysis on the potential interference caused by the deployment of BWA systems in the GHz band ( 3.5 GHz band ) to FSS networks in the GHz band. Technically, the potential impact caused by BWA on FSS earth stations have been identified in three categories, namely, (a) co-channel emissions from BWA causing in-band interference to FSS networks; (b) out-of-band emissions from BWA causing adjacent-channel interference to FSS; and (c) signals from nearby BWA transmitters causing saturation of LNA/LNBs of FSS earth station receiving antennas. The impact will not only be for FSS reception in 3.5 GHz, but also for all FSS networks with operating range in the entire GHz band. A. Assumptions and Methodology Typical technical parameters of BWA and FSS networks are used for evaluating in-band interference, out-of-band emissions and saturation of LNA/LNBs. A deterministic approach is employed to assess the concerned interference and the potential of sharing between BWA and FSS in the same or adjacent frequency bands in the GHz range. The approach is to calculate the separating distances between an FSS earth station and a BWA base station/user terminal to enable sharing between the two types of systems in the 3.5 GHz band. B. Categories of Interference In-band interference Typical technical parameters of BWA and FSS networks used for evaluating in-band interference are given in Figure 1. The typical pass loss of the power transmitted from a GEO satellite to an earth station is calculated by: L sat (R ) = 10 log (4πR /λ) 2 where R is the distance from the GEO satellite to the earth station, λ is the free-space wavelength of the satellite downlink in the C-band. The propagation of interference signal from a BWA base station/user terminal to an FSS earth station is based on a clear-air line-of-sight model provided in Recommendation ITU-R P.452 [1]. The path loss is calculated by the following: L BWA (d ) = log (f) + 20 log (d) + Ah db where d in km is the distance from a BWA base station/user terminal to an FSS earth station, f is the frequency of signal in GHz and Ah is the clutter loss which is 0 db for free air propagation and 18.5 db for dense urban areas. By calculation, L sat is around 98dB larger than L BWA in the C-band.

8 zone will depend on the technical parameters. The chosen parameters are representative for BWA systems and possibly also for IMT systems. Interference from out-of-band emissions Typical technical parameters of BWA and FSS networks used for evaluating interference from out-of-band emissions are given in Figure 3. Fig.1 Typical technical parameters of BWA systems and FSS networks used for evaluating in-band interference Due to the long distance to the satellite and the power limitations of the satellite, the incoming power flux density at the earth station location is very low. Terrestrial equipment which will be much closer to the earth station may produce significantly higher power levels. Total difference of signal levels is as high as 52 db at FSS earth station receiving antenna. As a result, exclusion zones around earth stations would be required if they were to be protected. Analyses indicate that a protection zone in the order of several hundred km may be required. As such kind of geographical separation may not be achievable in a dense urban environment, it is considered that co-frequency sharing between BWA and FSS in the 3.5 GHz band is not feasible. Fig.3 Typical technical parameters of BWA systems and FSS networks used for evaluating interference from out-of-band emissions Due to the very large difference in incoming signal levels, BWA emissions in one part of the GHz band can create interference in other parts of the band due to out-ofband emissions. In particular emissions close to the edge of a sub-band would seem likely to create interference to the band just on the other side if due care is not taken. Appendix 3 of the Radio Regulations provides limits for such out-of-band emissions [3]. Fig.2 Exclusion zones for protection of FSS earth stations from BWA in-band interference Figure 2 shows an example of what such required exclusions zones for protection of FSS earth stations in the same frequency band would look like. The dt/t values are compared to the 6% value allocated for the aggregation interference from all other co-primary services in Recommendation ITU-R S.1432 [2]. The size of the exclusion Fig.4 Exclusion zones for protection of FSS earth stations from BWA out-of-band emissions Also this effect can be mitigated by exclusion zones around the earth stations. The results of the required size of

9 the exclusion zone are shown in Figure 4. It can be seen that if all interference allowance was assigned to one single BWA transmitter, a separation distance of about 5 km would be required to provide the required dt/t = 6% protection of the FSS receiver. If it is assumed that a 200 MHz bandwidth is filled up with BWA transmitter (each with a used bandwidth of 3.5 MHz), an exclusion zone of several kilometers would be required. Saturation of LNA/LNB s of FSS earth station receiving antennas Typical technical parameters of BWA and FSS networks used for evaluating saturation effect of LNA/LNB s of FSS earth station receiving antennas are given in Figure 5. adverse impacts on FSS reception will apply also for IMT emissions. To avoid this happening, exclusion zones around the earth stations will be required. Figure 6 shows the results of the study. This study indicates that exclusion zones in the order of excess of a kilometer with respect to the base stations and several hundred meters with respect to user terminals are required around earth stations to ensure linear operation of the LNA s and LNB s. Although in principle adding a filter in front of the FSS receiver may mitigate the problem, this can only provide limited reduction of overdrive effects by about 10 db. In addition, insertion a filter reduces earth station figure of merit and may require use of larger antennas leading to increased cost. The filter itself is expensive which becomes a significant cost as well. Fig.6 Exclusion zones for protection of FSS earth stations from saturation of LNA/LNB s Fig.5 Typical technical parameters of BWA systems and FSS networks used for evaluating saturation effect of LNA/LNB s of FSS earth station receiving antennas Satellite LNA s and LNB s are designed for reception of very low satellite signals and the dynamic range is designed accordingly. Typically, an LNA or LNB will be saturated with a total incoming power of around -50 dbm. Accordingly, the LNA s or LNB s will start to show a non-linear behavior, creating intermodulation products and suppression of carriers at a total incoming power about 10 db lower than the saturation power, about -60 dbm. Traditional LNA s and LNB s receive the entire GHz band. LNA s and LNB s specified for reception of only the GHz band normally have the filtering at the IF side. Terrestrial signals in any part of the GHz band therefore can saturate satellite LNA s and LNB s or bring them into non-linear operation and thus block reception of signals anywhere in the entire GHz band, even if the terrestrial signal is not overlapping with the FSS signal. The C. Summary of the Technical Study Sharing studies have been performed to assess the technical feasibility of deploying BWA systems in the 3.5 GHz that are utilized by FSS (amongst other services). Based on the assessment, introduction of BWA or IMT in portions of the GHz band is seen to have implications on FSS reception in the entire GHz band. To provide protection of the FSS receiving earth stations, some technical constraints must be observed, for example some separation distance relative to the stations of the mobile terrestrial network is required. The magnitude of this separation distance depends on the parameters of the networks and the deployment of the two services. These constraints would imply significant costs to be incurred by both BWA operators and FSS users. III. REGULATORY ASPECTS At WRC-07 agenda item 1.4 sought global allocations for additional spectrum for IMT in the C-band frequencies used for FSS applications. Traditionally virtually all administrations have favored FSS in the C-band. WRC-07 did not adopt global allocations in the C-band but it did adopt opt-in footnotes in the GHz bands (3.5 GHz band) and administrations from all ITU Regions did sign such footnotes

10 (81 in Europe and Africa, 14 in the Americas and 10 in Asia and Oceania) [4]. Presently fixed wireless access (FWA) applications operating in the new in the 3.5 GHz band such as WiMAX cause interference into C-band FSS applications. In adopting its own table of frequency allocations an administration is free to decide which of the co-primary services to favor on its territory. Therefore an administration that has signed the IMT opt-in footnotes and operates FWA in the 3.5 GHz band is operating in conformity with Radio Regulations (RR) even when such operation may cause interference to FSS operations. New agenda items of WRC-15 seek additional spectrum for terrestrial mobile services including IMT and the C-band is again one of the bands that will be considered. Furthermore, another WRC-15 agenda item may change the definition of the fixed service to allow point-to-multipoint receive/transmit applications. Such applications have the same interference potential into FSS applications as mobile applications and may cause interference into FSS applications. A. WRC-15 Agenda Item 1.1 WRC-15 agenda item 1.1 calls for additional spectrum allocations to the mobile service on a primary basis and identification of additional frequency bands for International Mobile Telecommunications (IMT). This agenda item was expected since the terrestrial interests at WRC-07 obtained only opt-in country footnotes in the C-band and were not successful in obtaining global allocations for terrestrial IMT applications in the C-band. Satellite C-band spectrum is once again under threat. Satellite interest had attempted to exclude the FSS C-band from the review of possible new bands for mobile service including IMT since this band was reviewed under WRC-07 agenda item 1.4. However, WRC-12 decided that no frequency bands would be excluded a priori. The ITU-R Reports on BWA/FSS sharing and IMT/FSS sharing have both concluded that when the BWA/IMT stations and/or FSS earth stations are deployed in a ubiquitous manner co-frequency operation is not feasible [5][6]. As far as interference into FSS is concerned, land point-to-area transmit/receive applications (even when the two-way terminals are stationary) cause interference equivalent to applications in the mobile service. B. WRC-15 Agenda Item 9.1regarding Resolution PLEN/1 (WRC-12) Resolution PLEN/1 (WRC-12) is entitled: Studies towards review of the definitions of fixed service, fixed station and mobile station. This Resolution resulted from WRC-12 agenda item 1.2 which read: 1.2 taking into account the ITU-R studies carried out in accordance with Resolution 951 (Rev.WRC-07), to take appropriate action with a view to enhancing the international regulatory framework; This agenda item (1.2 above) dealt with studies on general spectrum management solutions to enhance the Radio Regulations in order to meet the demands of current and future technologies. One issue addressed under this agenda item concerned the convergence between fixed service (FS) and mobile service (MS). With the advent of new and emerging technologies, it is increasingly difficult to distinguish whether a station should be categorized as fixed or mobile Therefore, this agenda item examined the need or not to modify certain definitions related to the fixed service and/or mobile service in the Radio Regulations. Under this agenda item there were proposals to WRC-12 to broaden the definition of the fixed service to include point-to-area transmit/receive applications. This precludes sharing with FSS since the terrestrial transmit/receive terminals could be placed anywhere within an area and cause interference into FSS applications. This is now happening in the band GHz where broadband wireless access (FWA) applications (e.g. WiMAX) are causing interference into FSS applications. C. WRC-12 Decision on Agenda Item 1.2 WRC-12 decided that for now there would be no change to the definitions. However, to recognize the work that had been done on developing new definitions to address the convergence of terrestrial mobile and fixed services WRC-12 adopted Resolution PLEN/1 (WRC-12) which will review definitions of fixed service, fixed station and mobile station. The Bureau will report the results of these studies under Agenda Item 9.1 of WRC-15. D. Summary of Regulatory Aspects With respect to WRC-15 agenda 1.1 the satellite industry may lose more C-band spectrum for mobile terrestrial application including IMT. With respect to WRC-15 agenda 9.1 the goal of many administrations in reviewing the definitions fixed service, fixed station and mobile station is to allow point-to-area transmit/receive applications under the fixed service. Even if such proposals excluded the satellite bands (as was proposed at WRC-12) such a re-definition would close the door for any future use by the FSS of bands presently allocated on a primary basis to the fixed service but not the FSS. IV. CONCLUSION Sharing studies have been performed to assess the technical feasibility of deploying BWA systems in the 3.5 GHz that are utilized by FSS (amongst other services). Based on the assessment, it concluded that both BWA/FSS sharing and IMT/FSS sharing in the entire GHz band are not feasible. To provide protection of the FSS receiving earth stations, some technical constraints must be observed, for example some separation distance relative to the stations of the mobile terrestrial network is required. These constraints would imply significant costs to be incurred by both BWA operators and FSS users.

11 It has been noted that the concerned interference from BWA to FSS has been increasingly reported in the Asia Pacific region and have been brought to the attention of some industry organisations. The development of any practical solutions should be observed in order for the regulator to make a decision on whether to allocate the 3.5 GHz band for BWA or IMT services. REFERENCES [1] Prediction procedure for the evaluation of microwave interference between stations on the surface of the earth at frequencies above about 0.7 GHz, Recommendation ITU-R P.452. [2] Apportionment of the allowable error performance degradations to fixed-satellite service (FSS) hypothetical reference digital paths arising from time invariant interference for systems operating below 15 GHz, Recommendation ITU-R S [3] Radio Regulations, vol. 3, Appendix 3, 2008, pp [4] Radio Regulations, vol. 1, Article 5, 2008, pp [5] Studies on compatibility of broadband wireless access systems and fixed-satellite service networks in the MHz band, Report ITU-R S [6] Sharing studies between IMT-Advanced systems and geostationary satellite networks in the fixed-satellite service in the and MHz frequemcy bands, Report ITU-R M.2109.