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Between a rock and a hard place
Comment Between a rock and a hard place Olof Lundberg The forthcoming Mobile WARC to be held in Geneva in September 1987 is likely to determine the way in which mobile services develop for the foreseeable future. The impact of the WARC on international maritime and aeronautical mobile satellite communications is likely to be particularly crucial. In this article, Mr Lundberg outlines INMARSAT’s views on the future of mobile satellite services. Mr Olof Lundberg is Director General of INMARSAT, 40 Melton Street. London NW1 2EO. UK.
‘Mobile satellite services are likely to be the source of contentious debate at the Mobile WARC’
The World Administrative Radio Conference (WARC) for the Mobile Service, to be held in Geneva, for five weeks from 14 September 1987, will have a far-reaching impact on the development of mobile services for many years to come. It faces many difficult decisions, notably with regard to the disposition of the mobile satellite services in the L-band. The first three items on the agenda instruct the Conference to: (1) review, and revise as necessary,
The competence of the 1987 Mobile WARC, however, is limited to the mobile services within the scope of the agenda. It does not have the competence to allocate spectrum for mobile services from other bands. The focus of this article is on items 1 and 3. and in particular to the mobile satellite services, which are likely to be the source of most contentious debate at the Mobile WARC. Currently. there is a provision for maritime and aeronautical mobile satellite services at L-band (1.5-1.6 GHz). as follows: 0
0
The
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provisions of the Radio Regulations for the mobile services, the mobile-satellite services and the radionavigation and radiodetermination-satellite services; (2) include in the Radio Regulations any provisions required for the implementation of the Future Global Maritime Distress and Safety System (FGMDSS); (3) examine the requirement for the use of public correspondence by aircraft and make appropriate provisions if necessary
Maritime: 1530-1544 MHz (satellite to mobile) and 1626.5-1645.5 MHz (mobile to sarellite). Aeronautical: 1545-1559 MHz (satellite to mobile) and 1646.51660.5 (mobile to satellite). aeronautical
POLICY March 1987
band
has
an
‘R’
designation, meaning that only communications relating to the safety and regularity of flight can be accommodated within the band. Public correspondence (passenger communications) is not permitted. A one megahertz slot between the maritime and aeronautical bands is for distress and safety communications. INMARSAT’s second generation satellites will operate across the whole of the maritime band and its Notifying Administration, the UK, has filed an amendment with the International Frequency Registration Board (IFRB) notifying it of INMARSAT’s intent to cover up to 2 X 3 MHz in the AMSS (R) band in these satellites, the first of which is scheduled for launch in 198% 89, an increase of 2 X 2 MHz over the original specification for the second generation satellites. The only other spectrum allocated internationally for mobile satellite services below 3 GHz was referenced in a footnote to the International Table of Frequency Allocations at the 1979 WARC. Radio Regulation No 700 allows the use of the band 806-890 MHz. on a primary basis, for MSS in Region 2 (the Americas) and at 806890 MHz and 942-960 MHz in part of Region 1 (for Norway and Sweden). The maritime mobile satellite service (MMSS) bands are being used by INMARSAT. and several administrations have notified the IFRB of intent to use the AMSS (R) band as follows (see also Figure 1):
0
0
The USSR’s Volna lite networks cover the AMSS band. Japan’s Engineering (ETS V), scheduled August 1987, will
global satelthe whole of Test Satellite for launch in operate at
3
m i
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Comment
l
0
‘FCC to seek international recognition on the use of bands for MSS through freauencv allocation &angeS’ -sl
The Soviet networks use global beam satellites, as does INMARSAT, while the Japanese, Canadian and US satellites would provide regional coverage. It is important to note, in the context of the discussion which follows, that these spot beams would cover much of the Atlantic and Pacific Oceans. Much of the debate at the 1987 WARC will flow from decisions taken within the USA and Canada to open up the AMSS (R) band domestically for all forms of mobile satellite communications, land, aeronautical and maritime. In January 1985, the US Federal Communications Commission (FCC) issued a Notice of Proposed Rulemaking (NPRM) in which it proposed an allocation of the above-mentioned 8 MHz in the 800 MHz band and possibly an allocation in the AMSS (R) band for a mobile satellite service. It also invited applications for a licence and subsequently received 12 such applications. In September 1986, the FCC released its Report and Order, which allocated spectrum for MSS domestically as follows: 0
0
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1540.5-1543.5 and 1642.5-1645.5 MHz within the maritime band and 1545-1548 MHz and 16471650 MHz within the AMSS (R) band. ETS V is an experimental satellite with a design life of five years. Canada’s proposed Mobile Satellite (MSAT), now planned for launch in the early 199Os, would operate in the 800 MHz band, at 821-825 and 866-870 MHz, and would also cover the AMSS (R) L-bands. The US has notified the IFRB of three mobile satellite networks (designated as ACS 1, 2 and 3), which would also cover the whole of the AMSS (R) bands at Lband.
Two 4.5 MHz band segments will remain allocated for AMSS (R) on a primary basis (ie 15451549.5/1646.5-1651.0 MHz) with MSS permitted on a secondary basis. Two 9 MHz segments will be set aside for shared use by AMSS (R)
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l
and MSS (1549.5-15X5/16511660 MHz) with a footnote indicating that AMSS (R) will have priority over MSS use. The current two 0.5 MHz segments at 1558.5-1559/1660.01660.5 MHz will remain unchanged.
Surprisingly, it allocated no spectrum in the 800 MHz band for MSS, although it did leave open the possibility of 4 MHz (at 849-851 and 894-896 MHz) as an adjunct to a possible joint Canadian/US MSS system, ‘based on the principle of mutual comity’, but subject to negotiations with the Canadians. In reference to the L-band, the FCC said it would ‘seek international recognition on the use of the bands . . . for MSS at the 1987 Mobile WARC through appropriate frequency allocation changes’. In both its January 1985 NPRM and its September 1986 Report and Order, the FCC noted that the AMSS (R) band has been unused so far. In the NPRM, the FCC said, ‘We are unable to specify the exact amount of spectrum which will be allocated to the Mobile Satellite Service until the longterm spectrum requirements for the AMSS (R) service are identified’. In the Report and Order, the FCC said it believed the ‘L-band provides sufficient spectrum to wholly satisfy the needs of both MSS and AMSS (R)‘. The aviation community, both within the USA and internationally, have taken a different view. The International Civil Aviation Organization (ICAO) established in late 1983 a Special Committee on Future Air Navigation Systems (FANS), which has been looking at, among other things, the spectrum requirements of international aviation for satellite communications, navigation and surveillance (CNS). In its second report, released in April 1985, the FANS Committee concluded, ‘it is essential at the very least that the spectrum currently allocated to the AMSS (R) . . be maintained on an exclusive basis to satisfy the needs of international civil aviation’. In the report of its third meeting, 3-21 November 1986, the FANS Com-
5
‘There is too little spectrum in the AMSS (R) band to accommodate the aeronautical and land mobile communities’
‘A global allocation for AMSS is the only way to provide universal standards for aircraft’
6
mittee went further and recommended ‘that ail ICAO Contracting States ensure their position at the 1987 WARC is supportive of the ICAO viewpoint to retain exclusive use of the spectrum currently allocated to the aeronautical mobile satellite (R) service’. The Committee did, however, add another recommendation, which said that ‘until the aeronautical safety services require access to full spectrum, private correspondence of an organization (aeronautical administrative communications) and public correspondence (aeronautical passenger communications) could take place in the bands’. The US civil aviation community has adopted a similar stance. In a 23 November 1986 petition filed with the FCC, the Air Transportation Association, Aeronautical Radio Inc (Arinc), and others urged the FCC to reconsider its decision for the following reasons: ‘(1) the FCC ignored its own condition precedent in failing to examine aviation’s long-term needs before reallocating L-band spectrum to LMSS; (2) uncontroverted evidence shows AMSS (R) requires exclusive use of the full 28 MHz current allocation to serve the public; and (3) the agency’s action reallocating the Lband was both contrary to law and arbitrary and capricious.’ The FCC did not get any joy from the MSS community either. Five of the 12 applicants joined together as an MSS Coalition and, in a petition dated 24 November 1986, urged the Commission ‘to broaden and strengthen its allocation to the Mobile Satellite Service’. The key problems, as seen by the Coalition, in the FCC’s decision ‘concern its allocation of 9 MHz of the L-band to MSS on only a secondary basis and its adoption of a footnote for the 18 MHz MSS/AMSS(R) coprimary allocation that in effect renders MSS secondary in that portion of the band as well. A secondary allocation, with the prospect that it holds for automatic preemption of an existing MSS system, is simply too risky for an MSS operator. No potential MSS operator will build satellites to use secondary frequencies.’ This debate in North America over the disposition of the AMSS band has
already spilled over into Europe and elsewhere and will certainly reach its crescendo at the Mobile WARC. In my view, there is too little spectrum in the AMSS (R) band to accommodate both the aeronautical and land mobile communities. In the instance of aeronautical communications. the need for the full allocation should be obvious. New air traffic control (ATC) systems are being implemented in the USA and elsewhere. They will need spectrum. Air transport will continue to grow some 500 aircraft cross the Atlantic every day, with a maximum of about 250 aircraft simultaneously in the air at any one time (‘peak instantaneous aircraft count’). The latter figure is expected to increase to about 550 by the year 2010. In comparison, the Pacific currently has a peak instantaneous aircraft count of about 1300, which is forecast to rise to 3400 by the year 2010. Additional spectrum will be needed to provide for air safety around the world. A global allocation for AMSS is the only way to provide universal standards so that aircraft can circumnavigate the globe using the same antenna and avionics no matter where they are. High quality world-wide communications are equally important to commercial airlines if they are to improve the efficiency and effectiveness of their operations. The explosive growth of ACARS (Arinc Communications and Reporting System) in the USA and of the AIRCOM system operated by the SociCtC Internationale de Telecommunications Aeronautiques (SITA) in other parts of the world has resulted from the value to airline operators of the ability to control their systems flexibly and to adjust their operations to rapidly changing conditions. The current use of VHF radio limits the availability of these services to terrestrial and adjacent areas. Satellite communications would provide equivalent capabilities worldwide. During 1987, SITA, in cooperation with INMARSAT, will be demonstrating the expansion of the AIRCOM capabilities that can be achieved through the use of global satellite communications. The ICAO
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Commenl
‘In the fixed satellite service, a high degree of frequency re-use is possible’
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FANS Committee recognized the value of these types of services when they supported the use of the AMSS (R) band for aeronautical administrative communications until the aeronautical safety services required access to the full spectrum. In short, the AMSS band should remain exclusivelv for aeronautical including. public correspurposes, pondence with the condition added by ICAO. Although there may be doubts, especially in the minds of the land mobile proponents, about how fast the aviation community’s requirements will grow and how much spectrum it will need to accommodate those requirements, it is inevitable that the aviation community will eventually require the whole of the AMSS band. It would be short-sighted to accommodate the land mobile community until such time as the aviation community required the full band and then to expect that the land mobile community would willingly be pre-empted after having made an investment in the order of billions of dollars. The MSS Coalition notes that ‘for an MSS system to attract the necessary investment it is imperative that the L-band allocation be both large enough to provide sufficient spectrum and secure enough to eliminate the risk that the system, once launched, might be forced to cease operation. The necessary assurance can be provided only by allocating the full 28 MHz available at L-band to MSS on a co-primary basis with AMSS (R).’ Yet, as noted elsewhere in the MSS petition, the MSS system would not use the full 28 MHz since it would have to be shared with the Canadian MSAT (the notification for which went to the IFRB before the US notification). Additionally, as noted above, the USSR, Japan and INMARSAT have previously notified the International Frequency Registration Board of their intent to use a part or the whole of the band. Technically, it is very difficult to share the band, without chopping it up into small, discrete segments. As the FCC itself noted in its NPRM, ‘existing and incipient technology does not allow discrimination between two
March 1987
or more like MSS systems operating on the same frequencies’. In the fixed satellite service, a high degree of frequency re-use is possible. Two-degree or even less spacing between satellites is possible. The fixed satellite services and the mobile satellite services are, however. very different. It is extremely difficult, in fact virtually impossible, to share or re-use mobile satellite spectrum using today’s technology. Thirty-degree spacing in the orbital arc is not sufficient to avoid interference from omni-directional or even quasi-directional antennas between systems operating in the same frequency bands. Such antennas, either on the ground or in space, illuminate the whole hemisphere. Many of the land mobile satellite proponents in the USA have postulated, for their second generation satellites, use of nine-metre antennas, or even larger, to generate multiple spot beams which would enable frequency re-use. Such an arrangement would certainly give rise to the potential for frequency re-use due to the spatial separation of beams, but not, I believe, based on the use of orthogonal senses of polarization. It has also been claimed that the use of satellite spot beam antennas can lead to frequency re-use between neighbouring MSS networks. In the area where the coverage of the two networks overlap, however, and particularly where small mobile earth station antennas are to be employed. frequency re-use cannot be achieved. The problem is not one associated with the spacecraft antenna but is a function of the discrimination of the mobile earth station to the interfering transmission. Thus, there are serious difficulties in sharing and/or coordinating satellite systems operating in the same mobile satellite frequency bands. In the several notifications to the IFRB so far, from the USSR, Japan, INMARSAT, Canada and the USA (and more may follow), it is apparent that the footprints of the various systems would significantly overlap in the Atlantic and Pacific Ocean regions. If technical coordination of the spectrum and orbital locations were successful (an improbable if), one could see a scenario where the 28 MHz would be divided
7
‘Sharing the maritime band is no more feasible than sharing the aeronautical band’
‘As two examples: The Hughes application, dated 30 April 1986, to the FCC, on p 3-l 0 gives a target market of 342 000 rural telephones of a total of 1 026 000 (ie about one-third); rural telephony would consume 96.6 million minutes per month of a total 196.6 million minutes (almost half): and would use 6835 erlangs during the busy hour of a total 14 220 erlangs (almost half). All figures for 1991. The Skylink application, dated 30 April 1986, on p 44 of Vol 1, shows that rural and remote telephony would account for
106 000 terminals of a total 553 000 terminals. If the projected markets of 50 000 SCADA and 10 800 remote security terminals are added, this amounts to more than 20% of users. Rural and remote telephones would use 613 channels of a total of 3005 channels. SCADA would take 25 channels and remote security 9 of that total. All figures for 1988. Both Hughes and Skylink are members of the MSS Coalition.
8
amongst the five players - ie each gets 5.6 MHz. at least until other countries wanted a slice. Certainly, Australia, Indonesia. Europe. Mexico, Brazil and the Arab countries could reasonably be expected to want some of the spectrum at some point. Thus, one could foresee the AMSS band being chopped into many pieces, with perhaps 2 MHz for each player. This would be a disaster for the future of international mobile communications. particularly since some of those players want to use the scarce international mobile spectrum for fixed communications. ’ Are there alternatives to this scenario? I believe there are, but thev do not include a proposal referenced-in a 29 September 19S6 Meeting Notice from the FCC, with regard to the 19S7 WARC, for an MSS allocation in a wider frequency band - 1530-1559 MHz and 1626.5-1660.5 MHz - that is, across both the aeronautical and maritime bands. In their 24 November 1986 petition to the FCC, Arinc et al make reference to this current thinking and comment that ‘geographic separation of land and maritime mobile facilities . will facilitate sharing. Aircraft, by contrast, fly over land and oceans, making geographic sharing between aeronautical and other mobile satellite services impracticable.’ This comment, however, fails to recognize that sharing the maritime band is no more feasible than sharing the aeronautical band for the reasons given above: several of the networks notified to the IFRB operate global beam systems which are just that global. The beams do not neatly follow the coastline - in fact. INMARSAT’s beams cover much of the world’s land mass (with the notable exception of the polar regions). In any event, omnidirectional antennas, such as INMARSAT’s Standard C or those proposed by the Canadian and US MSS proponents, would illuminate the whole hemisphere making interference inevitable. point in suggesting My starting alternatives is to recognize the primacy of the international aviation and maritime communities. These two communities operate globally, need universal standards and global inter-
connectivity, and consequently need global frequency allocations. which are scarce. Erosion of their spectrum allocations would undermine the ability of these communities to operate on a world-wide basis, and by extension, hinder the free flow of trade and commerce. One alternative would be to consider a secondary allocation of perhaps 500 kHz for a low-speed data service for land mobile in the maritime band. The maritime community would not and could not object to such a secondary allocation which. while tiny, could accommodate several hundred thousand land mobile users globally. These calculations are based on use of technology similar to INMARSAT’s Standard C. Each Standard C 600 bits/s channel can provide up to about 200 000 characters per hour. Taking the example of a truck fleet management system, each truck may only have one or two brief messages per day, say 200 characters per day in total. Under these assumptions and the assumption that 10% of traffic occurs in the busy hour, a single Standard C channel could support some 10 000 trucks. Twenty Standard C channels occupying just 100 kHz could then support some 200 000 trucks providing an economical service using marginal satellite capacity. If it is assumed that the vast majority of land mobile communications in a developed area will eventually be provided through cellular radio, then 500 kHz might well be sufficient to support global land mobile message based communications. My recommendation would be to see what level of demand is generated by land mobile via a low-speed data service first. A land mobile satellite telephony service, however, would require a significant amount of spectrum, much more than could be accommodated in the aeronautical or maritime satellite bands. If there is. however, a clear demand for land mobile satellite telephoq service, an allocation should be made elsewhere in the L-band. The second alternative then would be somewhat along the lines of proposals which now appear to be considered within the Conference of European Post and
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Comment ‘It may, however, be less unpopular than might immediately be supposed. The CEPT, for example, has established a Groupe Special Mobile (GSM) which is developing the standards for a panEuropean cellular system. Administrations within CEPT have agreed to reserve the frequencies 905-915 MHz and 95C-960 MHz for the initial introduction of the GSM system. (Subsequently these bands are to be expanded to 890-915 MHz and 935960 MHz.) Eventually, there may well be a global allocation for a world-wide cellular standard. It is also interesting to note in the MSS Coalition’s petition of 24 November 1986, the note on p 13 in which they say, ‘Because the MSS Coalition believes that the Commission’s failure to allocate UHF spectrum [ie in the 800 MHz band] to MSS is not supported by the record, its members may seek judicial review of the Spectrum Allocation Order at the appropriate time’. Hughes and Mobilesat, two members of the MSS Coalition, have now filed petitions for review by the US Court of Appeal of the FCC’s spectrum allocation order. Court review will probably be held in abeyance pending FCC actipn on petitions for reconsideration. In its 24 November 1986 Petition for Partial Reconsideration (of the FCC spectrum allocation order) NASA said it is ‘concerned that the Commission’s total reliance upon L-band spectrum may be preinature at this point, in view of the uncertainty as to the outcome of the 1987 Mobile WARC at which such an allocation will be considered internationally. NASA thus urges the Commission to maintain its flexibility with respect to the use of the 800 MHz spectrum for the MSS service, at least pending the outcome of the 1987 Mobile WARC.
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Telecommunications (CEPT) administrations. These proposals suggest retaining separate aeronautical and maritime allocations and making new allocations at L-band for land mobile satellite telephony, in bands close to the existing maritime and aeronautical allocations. The 1987 Mobile WARC could make a recommendation to convene another WARC at the earliest opportunity, probably 1992, which would have the competence to allocate additional spectrum for mobile satellite services. In so doing, the 1987 WARC could resolve to find more spectrum for MSS, perhaps at L-band, and thus give advance warning to spectrum managers that other users, such as fixed or broadcasting, would have to move out over the longer term. In other words, the 1987 WARC need not be seen as the last chance to accommodate land mobile. It will probably take 5 years or longer before either the US or Canadian mobile satellites are launched anyway. A third alternative would be to reconsider the possibility of an allocation for land mobile satellite services in the 800 MHz band, which already has some standing internationally as noted above. This may not be popular with cellular radio operators’ who want more, rather than less spectrum, but it would be better than opening up the international maritime and aero-
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nautical bands. Satellite use of the 800 MHz band in North America would offer the opportunity, in theory at least, to have integrated satellite and terrestrial radio sets, so that users could switch from one system to the other, depending on the availability of each system in a given area, using only one mobile radio. The international maritime and aviation communities have no alternative to satellite communications. Land mobile does. Cellular radio, for example, is much cheaper, of higher quality and much more spectrum efficient by orders of magnitude. Even in remote and rural areas of the world, terrestrial systems can be erected. (In the remotest areas, such as the Sahara and northern Canada, the traffic would be very thin in any event, and what little traffic is generated could easily be accommodated by INMARSAT.) You cannot, however, erect microwave towers over the oceans. For that reason, international maritime and aviation needs should always have priority over land mobile’s needs. The stakes at the 1987 Mobile WARC are high indeed - they involve nothing less than the future of international maritime and aeronautical mobile satellite communications. We at INMARSAT hope that those holding the cards play their cards in favour of international cooperation, for now and in the years to come.
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‘Mobile satellite services are likely to be the source of contentious debate at the Mobile WARC’
The World Administrative Radio Conference (WARC) for the Mobile Service, to be held in Geneva, for five weeks from 14 September 1987, will have a far-reaching impact on the development of mobile services for many years to come. It faces many difficult decisions, notably with regard to the disposition of the mobile satellite services in the L-band. The first three items on the agenda instruct the Conference to: (1) review, and revise as necessary,
The competence of the 1987 Mobile WARC, however, is limited to the mobile services within the scope of the agenda. It does not have the competence to allocate spectrum for mobile services from other bands. The focus of this article is on items 1 and 3. and in particular to the mobile satellite services, which are likely to be the source of most contentious debate at the Mobile WARC. Currently. there is a provision for maritime and aeronautical mobile satellite services at L-band (1.5-1.6 GHz). as follows: 0
0
The
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the
provisions of the Radio Regulations for the mobile services, the mobile-satellite services and the radionavigation and radiodetermination-satellite services; (2) include in the Radio Regulations any provisions required for the implementation of the Future Global Maritime Distress and Safety System (FGMDSS); (3) examine the requirement for the use of public correspondence by aircraft and make appropriate provisions if necessary
Maritime: 1530-1544 MHz (satellite to mobile) and 1626.5-1645.5 MHz (mobile to sarellite). Aeronautical: 1545-1559 MHz (satellite to mobile) and 1646.51660.5 (mobile to satellite). aeronautical
POLICY March 1987
band
has
an
‘R’
designation, meaning that only communications relating to the safety and regularity of flight can be accommodated within the band. Public correspondence (passenger communications) is not permitted. A one megahertz slot between the maritime and aeronautical bands is for distress and safety communications. INMARSAT’s second generation satellites will operate across the whole of the maritime band and its Notifying Administration, the UK, has filed an amendment with the International Frequency Registration Board (IFRB) notifying it of INMARSAT’s intent to cover up to 2 X 3 MHz in the AMSS (R) band in these satellites, the first of which is scheduled for launch in 198% 89, an increase of 2 X 2 MHz over the original specification for the second generation satellites. The only other spectrum allocated internationally for mobile satellite services below 3 GHz was referenced in a footnote to the International Table of Frequency Allocations at the 1979 WARC. Radio Regulation No 700 allows the use of the band 806-890 MHz. on a primary basis, for MSS in Region 2 (the Americas) and at 806890 MHz and 942-960 MHz in part of Region 1 (for Norway and Sweden). The maritime mobile satellite service (MMSS) bands are being used by INMARSAT. and several administrations have notified the IFRB of intent to use the AMSS (R) band as follows (see also Figure 1):
0
0
The USSR’s Volna lite networks cover the AMSS band. Japan’s Engineering (ETS V), scheduled August 1987, will
global satelthe whole of Test Satellite for launch in operate at
3
m i
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POLICY March 1987
Comment
l
0
‘FCC to seek international recognition on the use of bands for MSS through freauencv allocation &angeS’ -sl
The Soviet networks use global beam satellites, as does INMARSAT, while the Japanese, Canadian and US satellites would provide regional coverage. It is important to note, in the context of the discussion which follows, that these spot beams would cover much of the Atlantic and Pacific Oceans. Much of the debate at the 1987 WARC will flow from decisions taken within the USA and Canada to open up the AMSS (R) band domestically for all forms of mobile satellite communications, land, aeronautical and maritime. In January 1985, the US Federal Communications Commission (FCC) issued a Notice of Proposed Rulemaking (NPRM) in which it proposed an allocation of the above-mentioned 8 MHz in the 800 MHz band and possibly an allocation in the AMSS (R) band for a mobile satellite service. It also invited applications for a licence and subsequently received 12 such applications. In September 1986, the FCC released its Report and Order, which allocated spectrum for MSS domestically as follows: 0
0
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1540.5-1543.5 and 1642.5-1645.5 MHz within the maritime band and 1545-1548 MHz and 16471650 MHz within the AMSS (R) band. ETS V is an experimental satellite with a design life of five years. Canada’s proposed Mobile Satellite (MSAT), now planned for launch in the early 199Os, would operate in the 800 MHz band, at 821-825 and 866-870 MHz, and would also cover the AMSS (R) L-bands. The US has notified the IFRB of three mobile satellite networks (designated as ACS 1, 2 and 3), which would also cover the whole of the AMSS (R) bands at Lband.
Two 4.5 MHz band segments will remain allocated for AMSS (R) on a primary basis (ie 15451549.5/1646.5-1651.0 MHz) with MSS permitted on a secondary basis. Two 9 MHz segments will be set aside for shared use by AMSS (R)
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and MSS (1549.5-15X5/16511660 MHz) with a footnote indicating that AMSS (R) will have priority over MSS use. The current two 0.5 MHz segments at 1558.5-1559/1660.01660.5 MHz will remain unchanged.
Surprisingly, it allocated no spectrum in the 800 MHz band for MSS, although it did leave open the possibility of 4 MHz (at 849-851 and 894-896 MHz) as an adjunct to a possible joint Canadian/US MSS system, ‘based on the principle of mutual comity’, but subject to negotiations with the Canadians. In reference to the L-band, the FCC said it would ‘seek international recognition on the use of the bands . . . for MSS at the 1987 Mobile WARC through appropriate frequency allocation changes’. In both its January 1985 NPRM and its September 1986 Report and Order, the FCC noted that the AMSS (R) band has been unused so far. In the NPRM, the FCC said, ‘We are unable to specify the exact amount of spectrum which will be allocated to the Mobile Satellite Service until the longterm spectrum requirements for the AMSS (R) service are identified’. In the Report and Order, the FCC said it believed the ‘L-band provides sufficient spectrum to wholly satisfy the needs of both MSS and AMSS (R)‘. The aviation community, both within the USA and internationally, have taken a different view. The International Civil Aviation Organization (ICAO) established in late 1983 a Special Committee on Future Air Navigation Systems (FANS), which has been looking at, among other things, the spectrum requirements of international aviation for satellite communications, navigation and surveillance (CNS). In its second report, released in April 1985, the FANS Committee concluded, ‘it is essential at the very least that the spectrum currently allocated to the AMSS (R) . . be maintained on an exclusive basis to satisfy the needs of international civil aviation’. In the report of its third meeting, 3-21 November 1986, the FANS Com-
5
‘There is too little spectrum in the AMSS (R) band to accommodate the aeronautical and land mobile communities’
‘A global allocation for AMSS is the only way to provide universal standards for aircraft’
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mittee went further and recommended ‘that ail ICAO Contracting States ensure their position at the 1987 WARC is supportive of the ICAO viewpoint to retain exclusive use of the spectrum currently allocated to the aeronautical mobile satellite (R) service’. The Committee did, however, add another recommendation, which said that ‘until the aeronautical safety services require access to full spectrum, private correspondence of an organization (aeronautical administrative communications) and public correspondence (aeronautical passenger communications) could take place in the bands’. The US civil aviation community has adopted a similar stance. In a 23 November 1986 petition filed with the FCC, the Air Transportation Association, Aeronautical Radio Inc (Arinc), and others urged the FCC to reconsider its decision for the following reasons: ‘(1) the FCC ignored its own condition precedent in failing to examine aviation’s long-term needs before reallocating L-band spectrum to LMSS; (2) uncontroverted evidence shows AMSS (R) requires exclusive use of the full 28 MHz current allocation to serve the public; and (3) the agency’s action reallocating the Lband was both contrary to law and arbitrary and capricious.’ The FCC did not get any joy from the MSS community either. Five of the 12 applicants joined together as an MSS Coalition and, in a petition dated 24 November 1986, urged the Commission ‘to broaden and strengthen its allocation to the Mobile Satellite Service’. The key problems, as seen by the Coalition, in the FCC’s decision ‘concern its allocation of 9 MHz of the L-band to MSS on only a secondary basis and its adoption of a footnote for the 18 MHz MSS/AMSS(R) coprimary allocation that in effect renders MSS secondary in that portion of the band as well. A secondary allocation, with the prospect that it holds for automatic preemption of an existing MSS system, is simply too risky for an MSS operator. No potential MSS operator will build satellites to use secondary frequencies.’ This debate in North America over the disposition of the AMSS band has
already spilled over into Europe and elsewhere and will certainly reach its crescendo at the Mobile WARC. In my view, there is too little spectrum in the AMSS (R) band to accommodate both the aeronautical and land mobile communities. In the instance of aeronautical communications. the need for the full allocation should be obvious. New air traffic control (ATC) systems are being implemented in the USA and elsewhere. They will need spectrum. Air transport will continue to grow some 500 aircraft cross the Atlantic every day, with a maximum of about 250 aircraft simultaneously in the air at any one time (‘peak instantaneous aircraft count’). The latter figure is expected to increase to about 550 by the year 2010. In comparison, the Pacific currently has a peak instantaneous aircraft count of about 1300, which is forecast to rise to 3400 by the year 2010. Additional spectrum will be needed to provide for air safety around the world. A global allocation for AMSS is the only way to provide universal standards so that aircraft can circumnavigate the globe using the same antenna and avionics no matter where they are. High quality world-wide communications are equally important to commercial airlines if they are to improve the efficiency and effectiveness of their operations. The explosive growth of ACARS (Arinc Communications and Reporting System) in the USA and of the AIRCOM system operated by the SociCtC Internationale de Telecommunications Aeronautiques (SITA) in other parts of the world has resulted from the value to airline operators of the ability to control their systems flexibly and to adjust their operations to rapidly changing conditions. The current use of VHF radio limits the availability of these services to terrestrial and adjacent areas. Satellite communications would provide equivalent capabilities worldwide. During 1987, SITA, in cooperation with INMARSAT, will be demonstrating the expansion of the AIRCOM capabilities that can be achieved through the use of global satellite communications. The ICAO
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Commenl
‘In the fixed satellite service, a high degree of frequency re-use is possible’
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FANS Committee recognized the value of these types of services when they supported the use of the AMSS (R) band for aeronautical administrative communications until the aeronautical safety services required access to the full spectrum. In short, the AMSS band should remain exclusivelv for aeronautical including. public correspurposes, pondence with the condition added by ICAO. Although there may be doubts, especially in the minds of the land mobile proponents, about how fast the aviation community’s requirements will grow and how much spectrum it will need to accommodate those requirements, it is inevitable that the aviation community will eventually require the whole of the AMSS band. It would be short-sighted to accommodate the land mobile community until such time as the aviation community required the full band and then to expect that the land mobile community would willingly be pre-empted after having made an investment in the order of billions of dollars. The MSS Coalition notes that ‘for an MSS system to attract the necessary investment it is imperative that the L-band allocation be both large enough to provide sufficient spectrum and secure enough to eliminate the risk that the system, once launched, might be forced to cease operation. The necessary assurance can be provided only by allocating the full 28 MHz available at L-band to MSS on a co-primary basis with AMSS (R).’ Yet, as noted elsewhere in the MSS petition, the MSS system would not use the full 28 MHz since it would have to be shared with the Canadian MSAT (the notification for which went to the IFRB before the US notification). Additionally, as noted above, the USSR, Japan and INMARSAT have previously notified the International Frequency Registration Board of their intent to use a part or the whole of the band. Technically, it is very difficult to share the band, without chopping it up into small, discrete segments. As the FCC itself noted in its NPRM, ‘existing and incipient technology does not allow discrimination between two
March 1987
or more like MSS systems operating on the same frequencies’. In the fixed satellite service, a high degree of frequency re-use is possible. Two-degree or even less spacing between satellites is possible. The fixed satellite services and the mobile satellite services are, however. very different. It is extremely difficult, in fact virtually impossible, to share or re-use mobile satellite spectrum using today’s technology. Thirty-degree spacing in the orbital arc is not sufficient to avoid interference from omni-directional or even quasi-directional antennas between systems operating in the same frequency bands. Such antennas, either on the ground or in space, illuminate the whole hemisphere. Many of the land mobile satellite proponents in the USA have postulated, for their second generation satellites, use of nine-metre antennas, or even larger, to generate multiple spot beams which would enable frequency re-use. Such an arrangement would certainly give rise to the potential for frequency re-use due to the spatial separation of beams, but not, I believe, based on the use of orthogonal senses of polarization. It has also been claimed that the use of satellite spot beam antennas can lead to frequency re-use between neighbouring MSS networks. In the area where the coverage of the two networks overlap, however, and particularly where small mobile earth station antennas are to be employed. frequency re-use cannot be achieved. The problem is not one associated with the spacecraft antenna but is a function of the discrimination of the mobile earth station to the interfering transmission. Thus, there are serious difficulties in sharing and/or coordinating satellite systems operating in the same mobile satellite frequency bands. In the several notifications to the IFRB so far, from the USSR, Japan, INMARSAT, Canada and the USA (and more may follow), it is apparent that the footprints of the various systems would significantly overlap in the Atlantic and Pacific Ocean regions. If technical coordination of the spectrum and orbital locations were successful (an improbable if), one could see a scenario where the 28 MHz would be divided
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‘Sharing the maritime band is no more feasible than sharing the aeronautical band’
‘As two examples: The Hughes application, dated 30 April 1986, to the FCC, on p 3-l 0 gives a target market of 342 000 rural telephones of a total of 1 026 000 (ie about one-third); rural telephony would consume 96.6 million minutes per month of a total 196.6 million minutes (almost half): and would use 6835 erlangs during the busy hour of a total 14 220 erlangs (almost half). All figures for 1991. The Skylink application, dated 30 April 1986, on p 44 of Vol 1, shows that rural and remote telephony would account for
106 000 terminals of a total 553 000 terminals. If the projected markets of 50 000 SCADA and 10 800 remote security terminals are added, this amounts to more than 20% of users. Rural and remote telephones would use 613 channels of a total of 3005 channels. SCADA would take 25 channels and remote security 9 of that total. All figures for 1988. Both Hughes and Skylink are members of the MSS Coalition.
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amongst the five players - ie each gets 5.6 MHz. at least until other countries wanted a slice. Certainly, Australia, Indonesia. Europe. Mexico, Brazil and the Arab countries could reasonably be expected to want some of the spectrum at some point. Thus, one could foresee the AMSS band being chopped into many pieces, with perhaps 2 MHz for each player. This would be a disaster for the future of international mobile communications. particularly since some of those players want to use the scarce international mobile spectrum for fixed communications. ’ Are there alternatives to this scenario? I believe there are, but thev do not include a proposal referenced-in a 29 September 19S6 Meeting Notice from the FCC, with regard to the 19S7 WARC, for an MSS allocation in a wider frequency band - 1530-1559 MHz and 1626.5-1660.5 MHz - that is, across both the aeronautical and maritime bands. In their 24 November 1986 petition to the FCC, Arinc et al make reference to this current thinking and comment that ‘geographic separation of land and maritime mobile facilities . will facilitate sharing. Aircraft, by contrast, fly over land and oceans, making geographic sharing between aeronautical and other mobile satellite services impracticable.’ This comment, however, fails to recognize that sharing the maritime band is no more feasible than sharing the aeronautical band for the reasons given above: several of the networks notified to the IFRB operate global beam systems which are just that global. The beams do not neatly follow the coastline - in fact. INMARSAT’s beams cover much of the world’s land mass (with the notable exception of the polar regions). In any event, omnidirectional antennas, such as INMARSAT’s Standard C or those proposed by the Canadian and US MSS proponents, would illuminate the whole hemisphere making interference inevitable. point in suggesting My starting alternatives is to recognize the primacy of the international aviation and maritime communities. These two communities operate globally, need universal standards and global inter-
connectivity, and consequently need global frequency allocations. which are scarce. Erosion of their spectrum allocations would undermine the ability of these communities to operate on a world-wide basis, and by extension, hinder the free flow of trade and commerce. One alternative would be to consider a secondary allocation of perhaps 500 kHz for a low-speed data service for land mobile in the maritime band. The maritime community would not and could not object to such a secondary allocation which. while tiny, could accommodate several hundred thousand land mobile users globally. These calculations are based on use of technology similar to INMARSAT’s Standard C. Each Standard C 600 bits/s channel can provide up to about 200 000 characters per hour. Taking the example of a truck fleet management system, each truck may only have one or two brief messages per day, say 200 characters per day in total. Under these assumptions and the assumption that 10% of traffic occurs in the busy hour, a single Standard C channel could support some 10 000 trucks. Twenty Standard C channels occupying just 100 kHz could then support some 200 000 trucks providing an economical service using marginal satellite capacity. If it is assumed that the vast majority of land mobile communications in a developed area will eventually be provided through cellular radio, then 500 kHz might well be sufficient to support global land mobile message based communications. My recommendation would be to see what level of demand is generated by land mobile via a low-speed data service first. A land mobile satellite telephony service, however, would require a significant amount of spectrum, much more than could be accommodated in the aeronautical or maritime satellite bands. If there is. however, a clear demand for land mobile satellite telephoq service, an allocation should be made elsewhere in the L-band. The second alternative then would be somewhat along the lines of proposals which now appear to be considered within the Conference of European Post and
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Comment ‘It may, however, be less unpopular than might immediately be supposed. The CEPT, for example, has established a Groupe Special Mobile (GSM) which is developing the standards for a panEuropean cellular system. Administrations within CEPT have agreed to reserve the frequencies 905-915 MHz and 95C-960 MHz for the initial introduction of the GSM system. (Subsequently these bands are to be expanded to 890-915 MHz and 935960 MHz.) Eventually, there may well be a global allocation for a world-wide cellular standard. It is also interesting to note in the MSS Coalition’s petition of 24 November 1986, the note on p 13 in which they say, ‘Because the MSS Coalition believes that the Commission’s failure to allocate UHF spectrum [ie in the 800 MHz band] to MSS is not supported by the record, its members may seek judicial review of the Spectrum Allocation Order at the appropriate time’. Hughes and Mobilesat, two members of the MSS Coalition, have now filed petitions for review by the US Court of Appeal of the FCC’s spectrum allocation order. Court review will probably be held in abeyance pending FCC actipn on petitions for reconsideration. In its 24 November 1986 Petition for Partial Reconsideration (of the FCC spectrum allocation order) NASA said it is ‘concerned that the Commission’s total reliance upon L-band spectrum may be preinature at this point, in view of the uncertainty as to the outcome of the 1987 Mobile WARC at which such an allocation will be considered internationally. NASA thus urges the Commission to maintain its flexibility with respect to the use of the 800 MHz spectrum for the MSS service, at least pending the outcome of the 1987 Mobile WARC.
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Telecommunications (CEPT) administrations. These proposals suggest retaining separate aeronautical and maritime allocations and making new allocations at L-band for land mobile satellite telephony, in bands close to the existing maritime and aeronautical allocations. The 1987 Mobile WARC could make a recommendation to convene another WARC at the earliest opportunity, probably 1992, which would have the competence to allocate additional spectrum for mobile satellite services. In so doing, the 1987 WARC could resolve to find more spectrum for MSS, perhaps at L-band, and thus give advance warning to spectrum managers that other users, such as fixed or broadcasting, would have to move out over the longer term. In other words, the 1987 WARC need not be seen as the last chance to accommodate land mobile. It will probably take 5 years or longer before either the US or Canadian mobile satellites are launched anyway. A third alternative would be to reconsider the possibility of an allocation for land mobile satellite services in the 800 MHz band, which already has some standing internationally as noted above. This may not be popular with cellular radio operators’ who want more, rather than less spectrum, but it would be better than opening up the international maritime and aero-
POLICY March 1987
nautical bands. Satellite use of the 800 MHz band in North America would offer the opportunity, in theory at least, to have integrated satellite and terrestrial radio sets, so that users could switch from one system to the other, depending on the availability of each system in a given area, using only one mobile radio. The international maritime and aviation communities have no alternative to satellite communications. Land mobile does. Cellular radio, for example, is much cheaper, of higher quality and much more spectrum efficient by orders of magnitude. Even in remote and rural areas of the world, terrestrial systems can be erected. (In the remotest areas, such as the Sahara and northern Canada, the traffic would be very thin in any event, and what little traffic is generated could easily be accommodated by INMARSAT.) You cannot, however, erect microwave towers over the oceans. For that reason, international maritime and aviation needs should always have priority over land mobile’s needs. The stakes at the 1987 Mobile WARC are high indeed - they involve nothing less than the future of international maritime and aeronautical mobile satellite communications. We at INMARSAT hope that those holding the cards play their cards in favour of international cooperation, for now and in the years to come.
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