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4C/338 (Annex 14)-E
Radiocommunication Study Groups /Subject:WRC-12 Agenda item 1.7
Source:Document 4C/TEMP/165
Reference:Documents 4C/190, 276, 298, 309, 317,327,329,330 / Annex 14 to
Document 4C/338-E
8 October 2009
English only
Annex 14 to Working Party 4C Chairman’s Report
Working document toward draft CPM text on
WRC-12 Agenda item 1.7
In applying Resolution 222 (Rev.WRC-07)in the current coordination meeting:
−How the requirements of AMS(R)S are accommodated?
−How the priority referred to in RR No.5.357A is afforded?
−How the protection of AMS(R)S from unacceptable interference is ensured?
−How the decision is made in that coordination meeting, e.g. on a consensual basis, on the majority basis or else?
In order to resolve some of the problems mentioned in this document, similar course of actions as contained in Resolutions 608 (WRC-03), 609 (Rev.WRC-07) and 610 (WRC-03) may need to be examined as appropriate, at the next meetings of WP 4C. This should not be interpreted to replace any method.
Questions and clarifications regarding the existing AMS(R)S systems
Provide a general background on the existing AMS(R)S systems. In particular it is needed to be explained and clarified how many systems exist that provide AMS(R)S services, what is the coverage area of each system and what is the spectrum available per system per coverage area e.g. (spectrum available for each AMS(R)S in ITU R2, ITU R1 and 3 and regional within ITURRegions, if any).Additionally, it is required to clarify how the overall objectives of Resolution222 (Rev.WRC-07) are achieved between Region 2 on the one hand and Regions1 and3 on the other hand (e.g. how coordination among the three ITU-R Regions is conducted for AMS(R)S systems, how spectrum is efficiently shared between Region 2 and Regions 1and3, including AMS(R)S systems).
AGENDA ITEM 1.7
(WP4C/WP5C,(WP4B),(WP 7B), (WP 7C), (WP 7D))
1.7to consider the results of ITUR studies in accordance with Resolution222 (Rev.WRC07) in order to ensure long-term spectrum availability and access to spectrum necessary to meet requirements for the aeronautical mobile-satellite (R) service, and to take appropriate action on this subject, while retaining unchanged the generic allocation to the mobile-satellite service in the bands 15251559MHz and 1626.5-1660.5MHz;
Resolution 222 (Rev.WRC07): Use of the bands 1525-1559 MHz and 1626.5-1660.5 MHz by the mobile-satellite service, and studies to ensure long-term spectrum availability for the aeronautical mobile-satellite (R) service
5/1.7/1Executive summary
[Text of the executive summary, not more that half a page]
5/1.7/2Background
The International Civil Aviation Organization (ICAO) standardized the use of the 1.6/1.5 GHz band in 1995 as an essential element of aeronautical mobile satellite systems to enable safety communications, and spectrum demand will increase for the next generation of aeronautical satellite communication systems. ICAO has also standardized the use of 1.6 GHz band by NGSO satellite systems to provide alternative satellite communication capability for provision of aeronautical mobile-satellite systems, including communication safety messages.
At WRC-97, the sub-bands 1 545-1 555 MHz (space-to-Earth) and 1 646.5-1 656.5 MHz (Earthtospace), were made generic mobile-satellite service (MSS) allocations with the provision RR No.5.357A, to prioritize and protect AMS(R)S. These bands had previously been exclusively allocated to the aeronautical mobile-satellite service (AMS(R)S) for communications relating to thesafety and regularity of flights (messages with priority 1 to 6 as per Article 44 of the Radio Regulations). For the sub-bands 1555-1559 MHz and 1656.5-1660.5 MHz, see also RRNo.5.362A.The use of these bands for provision of aeronautical mobile-satellite services [hadbeen small, but] is anticipated to increase with projected growth in aviation traffic and evolution of aeronautical services.
WRC-2000 adopted Resolution 222 (WRC-2000) resolving that, administrations shall ensure that the spectrum needed for AMS(R)S communications within priority categories 1 to 6 of RRArticle44 is accommodated. This could be achieved in advance through the coordination process, and when necessary and where feasible, through prioritization and real-time pre-emptive access. However, studies included in Report ITU-R M.2073 has concluded that prioritization and inter-system pre-emption between different mobile-satellite systems is not practical and, without a significant advance in technology, is unlikely to be feasible for technical, operational and economical reasons. WRC-07 revised Resolution 222 to remove the request for studies into the “inter system real-time pre-emption” issue, but added other areas of study instead.
Resolution 222 also (resolves 3) requires that “administrations shall ensure that MSS operators carrying nonsafety-related traffic yield capacity, as and when necessary, to accommodate the spectrum requirements for AMS(R)S communications within priority categories 1 to 6 of Article44” and to the GMDSS.
In coordinating MSS systems, in addition to the procedure of RR Article 9, the administrations having MSS systems in the above bands have agreed to a multilateral process by which assignments across the bands 1 525-1 559/1 626.5-1 660.5 MHz are coordinated and reviewed annually so as to ensure fair and efficient use of the radio spectrum. This multilateral process recognises the Radio Regulatory provisions and the communications needs of GMDSS and AMS(R)S and the resulting spectrum needed to accommodate their requirements.
[It is noted that additional 2 x 7 MHz for the MSS was allocated at WRC-03, this allocation does not appear to properly respond to the needs of safety communications for AMS(R)S communications since it is unable to use for the seamless worldwide operations due to the regional limitations and difficult sharing conditions in those bands]. {Editor’s note: to be placed elsewhere, perhaps}
[Views of some administrations:
One AMS(R)S operator has encountered difficulty several times in the ORM process for access to spectrum since 2003 since their spectrum requirements are treated on an equal basis with the other MSS operators. In particular, despite of the priority given by RR No. 5.357A their spectrum requirements were only satisfied for no more than 70% of their needs in the framework of one MLM group (Regions 1 and 3). When then considering the additional constraints coming from the other operators in Region 2 the overall resulting assignments for the AMS(R )S network were less than 50%. This is because the spectrum assigned in one MLM group (Regions 1 and 3) is not reusable with the other MLM group (Region 2).
In the past, at the ORM (Regions 1 and 3) there has not been a consensual agreement on the request of new assignments which resulted in no new assignments being made to any of the operators. Hence, as it is important for AMS(R)S safety communications needs to be accommodated in the long-term with stable access to spectrum, the disagreements in the ORM framework which may result in freeze of assigned spectrum between operators can cause undue operational constraints to the AMS(R)S network.
Moreover, the ORM assignments agreed under the provisions of the MoU of the MLM are not available in the public domain. This makes it very difficult for the aviation community to develop long-term plans for spectrum access in order to serve their safety communication needs.
The process is not sufficiently transparent to all parties.Consequently, there is a need to add some openness and transparency in the process.
Te current mechanism does not address in which unacceptable interference is caused to AMS(R)S.
Due to the above reasons, the view of some Administrations is that the provisions of RRNo.5.357A and Resolution 222 (Rev.WRC-07) have not been put into practice within the current framework of the multilateral frequency coordination meetings and in order to resolve such matter, Agenda item 1.7 was adopted by WRC-07.]
[Views of some other administrations:
The multilateral coordination process is conducted under Article 9 of the Radio Regulations and was established by the notifying Administrations of MSS networks to facilitate the coordination of these networks.
In line with the normal practice in frequency coordination for all types of satellite networks, the Administrations involved in the bilateral and multilateral processes conducted for the 1.5/1.6 GHz bands MSS networks have agreed to keep the coordination agreements confidential.
The current coordination process includes a validation process of requested spectrum assignments. In this process, AMS(R)S spectrum requirements should be clearly identified in accordance with RR Article 44categories 1 to 6.
To date, the coordination process has satisfied the spectrum requirements of the AMS(R)S operators. No dissatisfaction with the coordination outcome for an AMS(R)S operator has been raised to the level of the notifying Administrations resulting in an administration invoking the priority provision of RR No 5.357A.
Disagreement on the spectrum assignments for one MSS operator does not prevent required spectrum assignments from being made to an AMS(R)S operator.]
Taking into account the number of aircraft (more than 2000 globally equipped) already equipped with standardized AMS(R)S technology, the life cycle of the AMS(R)S systems spread over [several decades] and the technical and operational advantages of using the bands identified in RRNo. 5.357A, the preference of ICAO is for the AMS(R)S spectrum needs under this Agenda item to be accommodated in those bands.
Resolution 222 invites the ITU-R to study other appropriate methods to ensure long-term and stable spectrum availability and priority access for AMS(R)S in these bands, and to provide appropriate regulatory and operational provisions.
Only if the long-term requirements of the AMS(R)S cannot be met “within the existing allocations with respect to RR No. 5.357A while retaining unchanged the generic allocation for the mobile-satellite service in the bands 1525-1559 MHz and 1626.5-1660.5 MHz, and without placing undue constraints on the existing systems operating in accordance with the Radio Regulations” (invitesii) should “existing MSS allocations or possible,new allocations only for satisfying the requirements of the AMS(R)S for communications with priority categories1 to6 of Article44” (invitesiv) be studied.
[Also, depending on decisions taken by WRC-12, consequential action may be required to ensure that the provisions contained in Resolution 222 (Rev.WRC-07) that clarify the protection of AMS(R)S in the bands 1525-1559MHz and 1626.5-1660.5MHz are retained.]
5/1.7/3Summary of technical and operational studies and relevant ITU-R Recommendations
3.1Long term AMS(R)S spectrum requirements
Resolution 222 (Rev.WRC07) invites the ITU-R to study, as a matter of urgency, and among other things, the existing and future spectrum requirements of the aeronautical mobile-satellite (R) service. For that purpose, spectrum requirements have been estimated using certain methodologies. The results, contained in the draft new Report ITU-R M.[AMS(R)S SPECTRUM ESTIMATE], are derived from the aviation needs and existing and future satellite systems characteristics.
3.1.1Aviation needs
Flight movements
Information on flight movements is required to evaluate the number of aircraft located within a given airspace at any given time. The information can be based on the actual air traffic statistics, and/or on forecasts of future air traffic over a given airspace. Such statistics and trends are normally compiled by the relevant aviation authorities, e.g. by ICAO, IATA for worldwide data and by
Eurocontrol for the European region (e.g. Eurocontrol compiles long-term statistics of flight movements for 20 years ahead). A copy of the Eurocontrol long-term forecast (2008-2030) is provided in the following link
Communication needs of a single aircraft
The AMS(R)S communication needs of a single aircraft will in general depend on several factors, such as the airspace, operational concept, air traffic services provided for each different aircraft flight phase and position.
The identification and quantitative characterization of these communication needs is a complex matter. The ICAO Aeronautical Communication Panel (ACP) has recommended as guidance for the assessment of future communication requirements the “Communications Operating Concept and Requirements for the Future Radio System” (COCR, currently in Version 2), developed by Eurocontrol and FAA. The COCR describes in detail the aviation communication services required by single aircraft in each airspace domain and flight phase, and is a suitable basis for the purpose of the assessment of the needs of multiple aircraft. A copy of this document can be found at the following link
The COCR does not however define some important elements of the system design, forexample whether the communication requirements are carried by satellite or terrestrial means. Factors such as the determination of the communication requirements by satellite, whether point-to-multipoint transmission mode is used and the satellite system design will impact the spectrum requirements.
Communication needs of multiple aircrafts
The cumulative communication needs over a given airspace and a given time frame can be obtained by combining the information on flight movements in that area and time frame with the information on the communication needs of a single aircraft.
Two procedures were agreed by ICAO for assessing spectrum needs using a combination of the above information. One based on a simulated statistical approach which derives aviation requirements and then adapts these to satellite technologies and the second a deterministic approach based on a Peak Instantaneous Aircraft Count (PIAC) also adapted to satellite technologies. Thedifference between these two procedures occurs at the level of derivation of aviation requirements inputs, i.e. one considers a flight by flight and time iterated simulation and the other relies on estimation of the maximum number of aircraft over agiven airspace and the average communication information volume per aircraft.
The statistical simulated model works at a lower level of detail and should ensure that the specified message priority and latency of safety communication messages are taken into consideration.
3.1.2Satellite system characteristics and methodology
In order to derive the spectrum requirements from the aviation needs, a set of satellite characteristics are needed for the calculation. Some of these are the beam configuration (number and size of beams), the service area configuration per beam, the capacity per carrier, the data delay, the carrier separation, the band efficiency, the access scheme, the protocol inefficiencies, modulation, the satellite/terrestrial split of avionics traffic and so on.
The methodology to estimate the spectrum requirement over an airspace is in fourgeneral steps as follows:
1)Gather the information on aircraft statistics and communication needs for the chosen area and calculate from all aircraft the maximum communication needs in bits/second.
2)From 1) calculate for the chosen area the spectrum requirements for a satellite beam, taking into account the satellite characteristics (one beam may not cover the complete area).
3)Calculate the total spectrum requirement for the satellite system taking account of all beams over the chosen area.
4)Calculate the global spectrum requirements using frequency re-use between the different satellite networks.
3.1.3AMS(R)S requirements
It is noted that the estimation of AMS(R)S spectrum can be performed separately for the satellite forward link and for the satellite return link. The two components are in general different because of the different communication needs and protocols in both links.
The spectrum requirements for AMS(R)S vary depending on the area being considered, assumptions for the overall system design (e.g. how much traffic is carried by terrestrial means, and how much by satellite means), and the characteristics of the AMS(R)S system.
[Editor’s note: the table which is in Annex 2, summarizing the estimated spectrum requirements studies needs to be captured here.]
[The European airspace can be seen as a worst case in regards of the number of planes, and related communication requirements in 2025. For this area, the spectrum requirements for the year 2025 are estimated in the forward link at between [2.9] MHz and [3.3] MHz and not more than [1.3] MHz in the return link. The larger number is based on an assumption and use of a satellite system with sixspot beams over the European airspace region, the smaller number of an alternative satellite system design with 26spot beams over the European airspace region.
Enhanced analysis based on other assumptions, would lead to smaller spectrum requirements of between [0.4 and 0.7 MHz] in particular, that more traffic is carried by the terrestrial link, that there is the use of point-to-multipoint transmission mode and enhanced terminal performance.
When we consider a global Earth airspace the spectrum requirement is going to be slightly more, driven by the European requirements. European studies have shown that the global spectrum requirements for AMS(R)S in year 2025 will not exceed 5 MHz in the forward link and 2 MHz in the return link.]
3.2Other considerations
[Furthermore, NGSO systemsin a part of the 1610-1626.5 MHz band may deploy AMS(R)S services (subject to RR No. 9.21) which could also be used to satisfy the overall demand for the use of AMS(R)S spectrum.
The estimated spectrum requirement for AMS(R)S resulting from the ITUR studies did not take into account the potential AMS(R)S traffic carried by NGSO systems
From this perspective the current estimation for the RR No. 5.357Abands may [slightly] over estimate the spectrum estimation.]
[The estimated spectrum requirements for AMS(R)S resulting from some of the ITU-R studies did not take into account that most of the AMS(R)S traffic is currently carried out by terrestrial systems. This leads to the resultant spectrum requirements for AMS(R)S being over estimated)]
Regarding UAS spectrum requirements
Under WRC-12 Agenda item 1.7, the studies have assumed that unmanned aircraft operating in Unmanned Air Systems (UASs) will fly and appear as normal aircraft. TheAMS(R)S communication estimate in WRC-12 Agenda item 1.7 studies have included all communications from air traffic control centres to air vehicles, including those related to UASs. This assumption was identified as necessary for the separation of study of spectrum requirements for AMS(R)S between the Working Parties responsible for WRC-12 Agenda item 1.7 and Agenda item 1.3.
[TheWorking Parties also identified that the study of spectrum requirements under WRC-12 Agenda item 1.3 include the separate two way link from the individual UAS to its remote pilot which may be part of the AMS(R)S.Therefore, studies under WRC-12 Agenda item 1.3 may determine that some of these specific UASspectrum requirements fall within AMS(R)S priority categories 1 to 6 of RRArticle 44 for this part of the communication link.If these specific two way UAS remote pilot and UAS linkrequirements were to be used within the bands given in RR No.5.357A, after WRC12 then the spectrum requirements for AMS(R)S under WRC-12 Agenda item 1.7 would have been under estimated and the AMS(R)S inclusive total may exceed the available 2 x 10 MHz. If WRC12 agrees that this possibility exists, then UAS requirements should be considered outside of the provisions of RR No. 5.357A and Resolution 222 (Rev.WRC-07). {Editor’s note: further explanation of post WRC RRs may have to be moved into other considerations paragraph.}]