International Civil Aviation Organization 2011-09-16
AERONAUTICAL COMMUNICATIONS PANEL (ACP)
WORKING GROUP OF THE WHOLE
Montreal, 14 to 16 September 2011
REPORT OF THE FOURTH MEETING
2. AGENDA ITEM 2: FUTURE COMMUNICATION INFRASTRUCTURE, PROGRESS
UPDATE AND RECOMMENDATIONS
2.1.1 Seven working papers and nine information papers were presented under this agenda
2.2 Request for Support on Guidance Material on ATN/IPS
2.2.1 WP#04 was presented by the Secretary. This paper referred to Major Task 1 of the ACP
Work Programme agreed at WGW/03, which called upon WG-I to develop guidance material for the
ATN/IPS. Specifically, this item called for the development of: an IPV6 Addressing Scheme, a DNS
naming convention, security protocols and architectural guidance.
2.2.2 It was explained that the current membership of WG-I did not have the technical skills
nor adequate knowledge of the institutional framework supporting the global internet to complete this
task. Hence it was necessary to request States to provide further support in the form of personnel
possessing these skills and knowledge.
2.2.3 Some key points which made this both an urgent and difficult task were as follows:
Accommodation of the ICAO 24-bit code will require a large address space.
Securing a large address block requires lengthy justification, involving various
administrative bodies, ICANN, IANA, etc.
Opportunities for Domain name applications are limited and also involve negotiation
with various administrative bodies.
The selection of the domain name must to the greatest extent possible replicate current
naming conventions or provide similar utility while respecting internet naming
conventions, ie; matching aircraft registrations and flight IDs during the lifetime of a
On-going maintenance of the standards and guidance material will require liaison with
and understanding of the work of the Internet Engineering Task Force (IETF).
2.2.4 The nature of the problem facing WG-I and the need for support was accepted by the
meeting with various members stating that support would be forthcoming if a request was made.
2.2.5 In response to this it was agreed that the Secretary would draft a memo to ACP members
carrying a request for support along with an explanation of the tasks to be completed.
ACTION ITEM 4-1: Secretary to draft memo to ACP members requesting additional personnel to
support the development of guidance material on the implementation of ATN/IPS.
2.3 Proposed modifications to support future implementations of ATN/IPS standards in
2.3.1 WP05 was presented by the Secretary this paper called for Standards on the ATN/OSI to
be modified into a Recommended Practice.
2.3.2 This WP05 was the result of a Working Paper submitted to and accepted at WG-
M/18.The proposal was justified by the fact that the Internet Protocol Suite has superseded the OSI
protocols. WP05 contained suggested text for an amendment to Annex 10 Volume 3.
2.3.3 Many points were made opposing the proposal made in WP05. The first of which was
that for the foreseeable future only ground-ground communication would be IP-based. It was also stated
that some ground-ground communications systems had been implemented using OSI.
2.3.4 It was also stated that the suggested text was blunt to the point that it may cause some
States to cancel plans to implement facilities using the OSI protocols pending the development of an IPS-
based equivalent, which may take some years.
2.3.5 In light of the above it was agreed that the ATN/OSI should remain as a Standard
however notes should be appended explaining the following:
That at present the use of the IPS is the de-facto system used for ground-ground
That all new technologies being considered (AeroMACS, LDACS and future SATCOM)
for air-ground communications be IP-compatible.
This resulted in an action item being levied upon the Secretary.
ACTION ITEM 4-2: The Secretary to re-draft the proposal in WP05 so that the ATN/OSI remains as a
Standard while adding the Notes given in 2.3.5 above.
2.4 Progress report on SESAR project P15.2.4 ET
2.4.1 Two papers were presented on this subject by Nikos Fistos, namely: WP14, WP15. Luc
Deneufchatel then presented WP16.
2.4.2 SESAR project P15.2.4 (Future Mobile Data Link System Definition) is a key project
leading the definition of the future communication system that should meet the future COM requirements
for all phases of flight. Project P15.2.4 is expected to interact and provide input to various other SESAR
projects addressing other components of the FCI.
2.4.3 WP14 began with a general overview of the project, which is summarised as follows.
Project 15.2.4 project is split in two steps. The first step is referred to as the “Early Tasks” (ET) and has
started in March 2010 and the second step is referred to as the “Full Project” (FP) and is planned to start
in Q4 2011. The ET part is planned to continue until the start of the FP. This is currently expected to take
place at the end of October, 2011.
2.4.4 The meeting was told that there are 10 members participating in P15.2.4 including
ANSPs, the ground and airborne industry and EUROCONTROL.
2.4.5 In the ET part there were four group of activities addressing the following:
Refinement of operational requirements – EWA01
Multilink Operational Concept and Com Architecture – EWA02
Upper layers and QoS mechanisms – EWA03
LDACS selection facilitation activities – EWA04
It was pointed out that the “Early Tasks” only considered LDACS1 and not LDACS2.
2.4.6 WP14 focussed on EWA04 which had the following deliverables:
Interference mitigation techniques
Interference Scenarios and Compatibility Criteria for systems in L band
LDACS Testing Plan
2.4.7 The meeting was then told that the Full Project (FP) had two key objectives:
The specification of the new general elements of the Future Communication
The specification of one of the new data links the L-Band Digital Aeronautical
Communication System (LDACS).
2.4.8 The meeting was then told that the FP is expected to have four work areas:
WA1 - Operational Concept and Operational Requirements for the FCI
WA2 - Functional requirements, Logical Architecture, Interface specifications,
Protocol specifications, and identify a Physical Architecture
WA3 - verification and potentially validation activities (if operational projects in
SESAR with such requirement are identified with a compatible timeframe.
WA4 - the development of mock-up(s) for the selected candidate(s) for the new
terrestrial air-ground data link (LDACS1 and/or LDACS2) and undertake the
execution of laboratory measurements on mock-up(s) in order to propose one
LDACS system for the subsequent endorsement by ICAO.
2.4.9 It was explained to the meeting that when the first of the WA4 work is complete, ICAO’s
endorsement would be sought for the chosen system and the development of ICAO SARPS and Guidance
Material could begin with continuing support from P15.2.4.
2.4.10 WP15 described the “Mulitlink Concept”, a notion of concurrently using multiple data
links to support the time-critical communication exchanges in future operations.
2.4.11 The scope of the “Multilink Concept”, is currently limited to just the three future
technologies (LDACS, AeroMACS, and SATCOM) and the ATN/IPS-based network layer. This does not
preclude that some other data link technologies be used within the overall future FCI, supported by the
common ATN/IPS network layer.
2.4.12 Two key items for consideration were explained, i) trade-offs and ii) handover
2.4.13 The trade-offs were as follows:
Trade-off 1: Data link (DL) usage (Traffic over a single DL vs. Parallel duplicated traffic
over multiple DL)
Trade-off 2: Logon (Parallel logon vs. Sequential logon)
Trade-off 3: Number of DL (Use of 2 DL vs. Use of all available DL)
Trade-off 4: CoS selection (on per transaction basis or on a per message basis)
Trade-off 5: DL selection
Trade-off 6: Load balancing between DL
2.4.14 Given the emphasis on LDACS, the Secretary asked what would drive LDACS
implementation. Would it be new Services or an increase in traffic beyond a certain threshold? Nikos
Fistas and Luc Deneufchatel responded that for initial 4D operations, VDL Mode-2 would be satisfactory
however the QoS requirements for datalink applications supporting Full 4D operations would require the
improved performance of LDACS. It was also pointed out that the transition to full 4D Operations would
not make VDL Mode-2 obsolete in all airspace.
2.4.15 WP16 provided the status of work on Quality of Service (QoS) management and gave a
proposition for various Classes of Service (CoS).
2.4.16 The meeting was told that there is a clear need to define the way the air/ground data
exchanges, will meet the expected end-to-end performance in the future system. The assurance of this
performance will depend on Quality of Service (QoS) management. This covers the entire communication
chain linking end system ATM applications between ground and aircraft.
2.4.17 Five metrics were defined to measure the communication performance:
Packet flow degradation;
2.4.18 These were further defined by more complex parameters such as Expiration Time and
Continuity of Service, which were further discussed in WP16.
2.4.19 CoSs are attributes associated with each transaction that can be used by the air/ground
communication infrastructure to provide the required Quality of Service (QoS). Three CoSs were defined:
Multi link cos family (ML CoS) - for the most critical
ATS services/applications that would qualify for the
multi link concept. ,
Medium cos family (ML CoS) - for the remaining ATS
Best effort cos family (ML CoS) - for AOC
2.4.20 For WPs 14, 15 and 16, the meeting was asked to provide feedback and comments to
support the continuation of these activities. For LDACS it will be necessary to consider liaison with the
NSP for consideration of the DME issues (especially compatibility criteria). Annex 6 of WP14, provides
an initial consideration of the compatibility criteria to be considered and this could be used as a starting
point for discussion with the NSP. For WP16 there was also an additional requirement for the Secretary to
establish a liaison with the OPLINK Panel to ensure that the interface between systems is addressed in a
consistent and complementary way within the two panels. It is expected that in future meetings of the
WGW there will be a standing agenda item to discuss these issues. WGW participants were encouraged to
provide feedback on this item as soon as possible.
ACTION ITEM 4-3: Secretary to establish a liaison with the Oplink panel as required by paragraph
ACTION ITEM 4-4: WGW members to provide feedback on the material contained in the Annexes of
WPs 14, 15 and 16 over the next two months, with the intention of providing clear proposals at the next
ACTION ITEM 4-5: The Secretary to forward Annex 6 of WP14 to the NSP.
2.5 Selection of technology for the LDACS data link
2.5.1 WP19 was presented by Luc Deneufchatel. This paper re-iterated the “two path”
approach to the development of the Future Communication System to help ensure that an optimum
system was chosen. The paper explained that for this work to continue additional resources would be
needed and hence asked the meeting to encourage stakeholders to make additional resources available to
ensure the continuity of this work.
2.5.2 The Future Communications Study (FCS) identified two candidate technologies for
ground based air-ground communications, operating in the L-band (960-1164 MHz), LDACS1 and
LDACS2. It was decided that because of the very challenging RF-environment, the selection would have
to be based on results from tests of LDACS prototypes operating together with legacy systems operating
in the band.
2.5.3 WP19 made the point that, the use of DME-DME navigation as a back-up to GNSS
would result in increased DME implementations thus aggravating the problems of RF interference to
LDACS. Hence the need to assess two technologies becomes more crucial.
2.5.4 The paper called on the meeting to endorse to two-path approach to LDACS selection
and also called upon States to devote sufficient resources to the LDACS evaluation to ensure a sound and
objective evaluation of the technology choices.
2.6 Update of VDL Mode 4 activities
2.6.1 Larry Johnsson delivered WP20 providing an update of VDL Mode-4 activities. A key
point was the fact that ETSI, EUROCAE and ICAO provisions were being updated to accommodate the
latest developments. Among these were such things as improvements to point-to-point and broadcast
performance. It was also pointed out that work was on-going to improve the handover between VDL
Mode 4 cells.
2.6.2 The paper went on to describe developments to allow VDL Mode 4 to act as an effective
ATN/IPS Subnetwork. A special version of mobility, called “Ground NEMO” was developed and proven
to be very efficient in this regard. Consequently Doc 9816 has been updated to included provisions for
Ground NEMO. The success of these efforts has led to VDL Mode 4 being recognised as a suitable media
over which to validate many elements of SESAR.
2.6.3 Work had also been undertaken to expand the frequency planning parameters for VDL
2.6.4 The meeting was asked to note these developments and to also encourage the aviation
community to use VDL Mode 4 and the ATN/IPS transport layer as the initial communication system
when developing new data link services and implementing initial data link services for gaining early
2.7 Future mobile satellite communication
2.7.1 This item was covered by WP 17 and IP4 and 12.
2.7.2 WP17 was introduced by Nikos Fistas. This paper provided information on the purpose
and activities of the EUROCONTROL NexSAT Group (http://www.eurocontrol.int/nexsat/) which
is examining the need to update the existing AMS(R)S SARPS to include stringent performance
requirements to support the emerging SESAR/NextGen operating concepts.
2.7.3 The requirements for satellite communications in Europe are especially stringent as it is
being considered as a complement to terrestrial communications.
2.7.4 The NEXUS group had embarked on the following two step programme:
Step 1 – Development of a consolidated proposal to ICAO for an Update of existing
AMS(R)S SARPs with stringent performance requirements required to support the future
ATM concept in the 2020+ timeframe (technology independent).
Step 2 - Provide a recommendation to ICAO for a candidate system supporting the
updated AMS(R)S SAPRS (new part of the AMS(R)S Manual) ( technology dependent).
2.7.5 The meeting was advised that suitable volunteers had been identified and that work had
begun on Step 1.
2.7.6 WP17 asked the meeting participants to comments on the described process to update the
AMS(R)S SARPS with technology independent performance based requirements suitable for the services
of the future ATM concept
2.7.7 IP04 was presented by Nikos Fistas. This paper discussed SESAR Project 15.2.6, the
objective of which is to define the requirements, for a future safety-of-life satellite communication system
for the European Air Traffic Management System.
2.7.8 This project is part of an overall initiative to integrate the terrestrial and satellite ATM
networks in order to realize a multilink link system and to complement the terrestrial links in terms of
coverage and diversity of the infrastructures and radio spectrum. This “dual link” concept was introduced
as a way to limit the impact of events that are critical such as, Loss of Service
2.7.9 Also given were the following key project activities:
To define the Iris mission requirements (MRD) identifying the satellite link operational
To define the SATCOM system interfaces (ICD) with the overall SESAR infrastructure,
To support the validation of the ESA Iris development from an end-to-end point of view
in collaboration with P15.2.4 for the FCI Operational Concept
To support the standardization processes related to the satellite communication system
and promoting the aviation technical standard to regional and international
2.7.10 One of the key current activities is the definition of an update of the AMS(R)S SARPs for
the future satellite data link (by the Nexus WG).
2.7.11 As this was only an information paper, the meeting was asked to note the contents of the
paper and advised that any interested parties should contact the author for further information.
2.7.12 IP12 was introduced by Nathalie Ricard. This paper described the status of ESA Iris
Programme activities, which aim at designing, developing and validating a new satellite communication
system for air-ground safety communications within the framework of the Single European Sky ATM
Research (SESAR) Programme
2.7.13 It was explained to the meeting that the Iris programme was considering two possibilities;
The possible adaptation of the INMARSAT SwiftBroadband characteristics
The development of new protocols (ANTARES study).
2.7.14 The first item had the benefit of global interoperability with the INMARSAT system,
whereas the second proposal lends itself to the development of a new-generation of low-cost avionics.
2.7.15 ESA is carrying out 3 studies of the business case with satellite operators and candidate
service providers, while SESAR JU is undertaking a Cost-Benefit Analysis.
2.7.16 The system design of ANTARES can be used on any type of orbit. The coverage of the
European core area can be provided with a Geostationary satellite but it was clearly understood that a
Highly Elliptical orbit would provide coverage over the polar-regions.
2.8 Airport Surface Communications
2.8.1 This item was covered by Information Papers 5 and 11. These dealt with the development
activities to provide an Airport Surface Communication solution for the SESAR and NextGen
2.8.2 IP5 specifically described SESAR Project 15.2.7 which covers the ground component of
the system. It was also mentioned that SESAR Project 9.16 covers the airborne component. Both projects
are cooperative projects with industry and are supported by a number of industry partners.
2.8.3 Project 15.2.7 has the following outcomes:
a) Contributions to the development of the required AeroMACS standards in the appropriate
groups in EUROCAE, RTCA and ICAO (MOPS, MASPS, SARPS etc)
b) Pre-industrial prototypes, developed by the SESAR industrial members (Indra, Thales
2.8.4 IP11 specially described the FAA, AeroMACS project which has the following specific
To identify the portions of the IEEE standard best suited for airport surface wireless
communications, identify and develop any missing functionality and propose an aviation
specific standard to appropriate standardisation bodies;
To evaluate and validate the performance of the aviation specific standard to support
wireless mobile communications networks operating in the relevant airport surface
environments through trials and test bed development;
Propose a channelization methodology for allocation of safety and regularity of flight
services in the band to accommodate a range of airport classes, configurations and
Complete business analysis in relation to the FCI components and implementation from
the perspective of the ground infrastructure and the airlines.
2.8.5 One of the key accomplishments to date was the implementation of a trial system at
Cleveland Airport, which had generated some promising results, especially in terms of mobile hand-offs.
2.9 Of special interest to the Meeting was the fact that the AeroMACS profile had been
completed by the RTCA SC223 and EUROCAE WG-82 groups. This would allow the ACP to commence
work on provisions for an airport surface communication system.
3. ACTION ITEMS
3.1 Secretary to draft memo to ACP members requesting for additional personnel to support
the development of guidance material on the implementation of ATN/IPS
3.2 The Secretary to re-draft the proposal in WP05 so that the ATN/OSI remains as a
Standard while adding the Notes given in 2.6.2 above.
3.3 Secretary to establish a liaison with the Oplink panel as required by paragraph 2.4.19.
3.4 WGW members to provide feedback on the material contained in the Annexes of WPs
14, 15 and 16 over the next two months, with the intention of providing clear proposals at the next WGW.
3.5 The Secretary to forward Annex 6 of WP14 to the NSP.
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