AERONAUTICAL MOBILE COMMUNICATIONS PANEL (AMCP)
Working Group C – 4th meeting
Montreal, Canada
27-30 May 2002
Agenda Item 4: Report to AMCP/8
Draft WGC Report to AMCP/8
"Communication scenarios
from present until and beyond 2010"
Presented by the Rapporteur
SUMMARY
This working paper contains a strawman version of the report under development by WGC as an input to AMCP/8.
AMCP WGC4/WP2
AMCP-WG C report
Communication scenarios from present until and beyond 2010
The need to achieve a common interoperable communication infrastructure beyond 2010
1
Executive Summary 3
1.0 Background 4
Comments to: 4
2.0 Introduction to report 4
Comments to: 4
3.0 Scope of report 5
Comments to: 5
4.0 The events since the 10th Air Navigation Conference 5
Comments to: 5
5.0 Present Situation 5
Comments to: 5
Introduction 5
Systems under consideration 5
General Systems overview 6
Functional description matrices 8
Service types for communications 1
Phase of movement: 3
Status of ongoing activities 4
Programs and future activities 5
Issues raised 6
6.0 The problem statement 7
Comments to: 7
7.0 Determining the future Need 7
Comments to: 7
The perceived need 7
The Optimum Infrastructure. 8
8.0 Operational Communication Requirements 8
Introduction 8
Operating Concept 8
Existing Communication Operating Concept 9
Required Communication Performance 12
Quality of Service 12
Users 13
User Information 13
Human - Machine Requirements 14
Capacity 14
Technologies 15
9.0 Communication Service Requirements 15
Comments to: 15
Introduction: 15
Communication service characteristics 15
Communication precedence, priority and access 15
RF Characteristics 15
Emissions 15
Signal Acquisition and tracking 15
Communication loading 15
Communication acknowledgement requirements for voice and data 16
Voice communication set-up and processing delay 16
Packetized data transmission 16
ATN Compatibility and standardized voice interfaces 16
10.0 Future alternatives 16
Comments to: 16
INTRODUCTION 16
SYSTEMS TO BE INTRODUCED IN THE FUTURE COMMUNICATION ARCHITECTURE 16
POINTS/CONSTRAINTS TO BE CONSIDERED IN A FUTURE COMMUNICATION ARCHITECTURE 1
11.0 Scenarios 2
Comments to: 2
SCENARIO 1 3
SCENARIO 2 6
SCENARIO 3 8
12.0 Institutional Aspects 9
Comments to: 9
Standardisation 9
Certification 10
Radio Spectrum Allocation 10
Implementation planing 10
Service provisions 10
Costs considerations 10
Intellectual Property 10
13.0 Summary and Conclusion 10
14..0 Recommendations to AMCP/8 10
Appendices 10
Appendix X: Definitions and Acronyms 10
Appendix Z: Info 10
References 11
Executive Summary
1.0 Background
Comments to:
The lack of a clear global operational ATM concept increases the technologic and investment risk to the aviation community for the necessary supporting communication, navigation and surveillance infrastructure. Not having clear stated operational requirements causes the development of the various CNS variants to meet perceived operational requirements in the anticipation that it will at least meet a subset of the overall requirements. For the communication element this has led to the development and standardisation of competing technologies for voice and data link services with complementary and overlapping characteristics.
Initially these systems might bring early benefits, however it could result in a patchwork of different Regional and National communication networks increasing the overall infrastructure costs whilst reducing the quality of service. AMCP/7, recognizing the risk of the proliferation of system solutions, has assigned the following tasks to ICAO WG-C:
a) to explore the long-term system requirements for aeronautical VHF systems in the light of the ATM concept, scenarios for all flight and operational requirements for implementation for beyond 2010 to be developed by the ATMCP, and;
b) to explore the likely airspace user needs for aeronautical VHF systems beyond 2010.
The tasks are related to the VHF systems after 2010, however they can’t be properly addressed without due consideration to aeronautical communications services in other radio frequency bands.
Improved communication is the enabler and not the end-goal, hence communication is a pure cost element within the overall CNS/ATM system concept. Therefore the introduction of the future communication infrastructure should be guided by:
a) The operational need in terms of performance and capacity and
b) The optimum infrastructure to meet this need.
Considering the lead-time required deploying the necessary infrastructure for a successful implementation transition planning is essential to provide a road map towards a common global interoperable communication infrastructure which can evolve in capacity and services with the air traffic growth.
2.0 Introduction to report
Comments to:
The report is intended to make an inventory of the problems the aviation community is facing with the introduction of communication technology with the objective to provide guidance towards a harmonized global communication infrastructure.
The report provides and overview of the present situation that is being used as the basis for the various implementation scenarios towards 2010 through an assessment of already ICAO standardized systems. These scenarios are analyzed on their merits in conjunction with the developments in the mobile communication industry of 2.5, 3 and possibly 4th Generation systems.
3.0 Scope of report
Comments to:
The report is basically constrained to communication service for Air Traffic Management (ATM) with the VHF communication as the initial focal point. Where frequency, increased services and capacity needs or integration aspects are involved other aeronautical communication services and systems will be included in the considerations.
Within the ATM CNS service elements only the communication service element and the surveillance service element are considered. Furthermore, the surveillance service element is only considered to the extent that is supported through a data communication system.
The report is written as a self-contained document with the caveat that appropriate qualitative and quantitative statements are documented in reference material.
4.0 The events since the 10th Air Navigation Conference
Comments to:
5.0 Present Situation
Comments to:
Introduction
Considering the difficulty to state future operational performance requirements for mobile communication and surveillance, an evolutionary way has to be sought to improve the aeronautical communication capability and capacity. Before this, an inventory of presently operating systems and ongoing and planned trials for newly standardized technologies is needed. However, the picture of the first step toward a new communication infrastructure is becoming more clear, namely: in addition to the present operating voice systems, AMSS and HF data link for long range communications and VHF VDL Mode 2 for non-priority communications.
This chapter intends to make an inventory on the status of presently ICAO standardized systems mobile communication systems, as part of the Annex 10, Volume III.
At present almost every communication exchange is conducted by voice: ATC, ATS (ATIS, VOLMET…). The infrastructure supporting them is mainly based on the 25 kHz and 8.33 kHz VHF DSB-AM technologies. HF is also used in oceanic and remote regions.
For ATS, limited use is made of data communication using ACARS, ARINC 622 Protocols over VHF, and AMSS.
Systems under consideration
This section provides a high level technical and operational description of the ICAO standardized mobile communication systems. Besides a brief introduction for each of them, the main technical information is categorized as a set of tables. The structure, scope and content of the tables have been defined in accordance with the objectives of this report.
General Systems overview
VHF 25 kHz and 8.33 kHz DSB-AM
25 kHz
VHF 25 kHz DSB-AM has been implemented for all international flights and supports all current voice communications between controllers and pilots. Transmission is made on a double side band (DSB) amplitude modulation (AM) carrier. The frequencies are selected within the band 118 – 137 MHz.
[TBC: spectrum allocations]
8.33 kHz
8.33 kHz channel spacing was recognized as the only medium term solution to alleviate the European congestion in VHF communication band and was implemented 7th October 99 within the FIR/UIR of the core Europe (Austria, Belgium, France, Germany, Luxembourg, Netherlands, Switzerland). Carriage of 8.33 kHz channel spacing R/T equipment is then mandatory for all aircraft when operating or capable of operating above FL 245.Projects for horizontal (ie outside core area) and vertical (ie above FL 195) exist
Note: in some regions of the World, aircraft are still flying with 50 kHz or even 100 kHz VHF radios.
[TBC: spectrum allocations]
HF SSB
HF SSB (single side band) is operated in the band 2.8 MHz - 22 MHz, which is allocated to the aeronautical mobile (route) service. This system supports voice communication exchanges in oceanic and remote regions.
[TBC: spectrum allocations]
HF Data Link
ICAO SARPs for HF data-link are applicable from 1999. HF data link uses bands between the 2.85 MHz - 22.00 MHz range. This system uses a bit-oriented air-ground protocol which conforms to the open system interconnection (OSI) model and is designed to function as a sub-network of the ATN. Also operating in ACARS mode
The data link appears to offer a practical means of data communications that could be utilized to backup or complement to satellite data link. HF data-link can provide coverage at high latitudes, where satellites are unusable.
[TBC: spectrum allocations]
AMSS
In this part of the document only the 1st generation satellites system will be addressed. A number of types of satellite communications are in existence or proposed for implementation to support air-ground data link communications as one of their functions (satellite systems can support a very wide range of communications requirements). Most of these systems are proposed to operate on one of three main principles:
a) geo-stationary orbit satellite (GEOS);
b) medium earth orbit satellite (MEOS); and
c) low earth orbit satellite (LEOS).
ICAO SARPs for 1st generation AMSS are applicable from 1995. With GEOs. Civil Aviation has lost its exclusive allocation but spectrum is still available in the L band. Voice and data channels to aircraft are available now from third party providers (mainly using INMARSAT satellites). Data may be ATN or ACARS compliant
ACARS
Some data-link services use non ICAO standard systems (e.g. ACARS/ARINC 622 in the Pacific and ACARS/ARINC 623 in continental Europe). ACARS is a 25 kHz VHF system which was originally designed for AOC services. Since the introduction of protocols like ARINC 623, it has been increasingly used, for ATS communications in particular.
ACARS extensions exist on HF or AMSS (see above)
Mode 2 Data link
ICAO SARPs and guidance material on this air-ground data-link are applicable from 1997.
VDL Mode 2 is an evolution from ACARS and uses a D8PSK modulation scheme to support improved data rate (31.5 kb/s). It supports data only and is designed to be ATN compliant, but can operate without the full ATN stack.
VDL Mode 2 subnetwork is not designed to support time critical applications. Due to the access mechanism (CSMA) it exhibits a non deterministic behavior and it cannot guarantee a required performance level in terms of transfer delay.
Mode 3 Data link
At SP COM/OPS/95 Meeting, this system was accepted to replace the VHF DSB-AM systems in the long term, whereas the new 8.33 kHz channel spacing would be implemented in Europe. Mode 3 allows four 4.8 kb/s links for voice or data on a 25 kHz channel, using a self organized time division multiple access principle (TDMA). The data capability is a constituent mobile subnetwork of the ATN. In addition, the VDL may provide non-ATN functions.
ICAO SARPs and guidance material were published (76th amendment of Annex 10) by November 2001. Planning criteria in the COM band (117.975 – 137 MHz) are not yet fully defined.
Mode 4 Data link
The SP COM/OPS/95 requested the development of SARPs for data links to support navigation and surveillance elements of CNS/ATM applications. Data links, which were considered by ICAO at that time, were SSR Mode S extended squitter and VDL Mode 4.
VHF DL Mode 4 is based on a self organized time division multiple access principle (STDMA), using a 19.2 kb/s GFSK modulation scheme. Point-to-point and broadcast data surveillance applications are supported, both as a subnetwork of ATN and as non-ATN specific services.
ICAO SARPs and guidance material were published (76th amendment of Annex 10) by November 2001, and Mode 4 has been approved for surveillance applications. Planning criteria in the COM (118 – 137 MHz) and NAV (108 MHz- 117.975 MHz) bands are not yet fully defined. Mode 4 would need two global signaling channels and several local channels.
SSR Mode S
ICAO SARPs are available since 1996. SSR Mode S is the next-generation ground-based radar surveillance system. In addition to its SSR Mode A/C and Mode S surveillance capability, Mode S supports full data link transactions and is defined as an aeronautical telecommunication network (ATN)-compliant sub-network.
Mode S Elementary Surveillance enables the use of the unique 24 bit aircraft address for selective interrogation and to acquire the Aircraft Identity (Call Sign or Registration mark) from the aircraft.
Mode S uses selective interrogation to communicate with aircraft, hence eliminating several problems found with the existing Mode A/C surveillance. However, Mode S is fully compatible with Mode A/C and supports ACAS which uses the same frequencies (1 030 MHz and 1 090 MHz).
Extended squitter is an addition to the Mode S system designed to support ADS-B and SMGCS which will also allow enhancements to ACAS. Extended squitter consists of a set of broadcast messages that provide information on the aircraft position, velocity, identification... It uses the same format as the current Mode S data link and operates on the Mode S down-link frequency.
[TBC: spectrum allocations]
MLS
MLS provides precision approach guidance for all categories of landings. The MLS data link uses differential phase shift keying (DPSK) modulation and cyclic redundancy checking (CRC) to ensure integrity and performance. MLS operates in the 5 030 MHz - 5 091 MHz band with 200 channels spaced on 300 kHz centre frequencies and 200 channels reserved for future use in the 5 091 MHz - 5 150 MHz band.
[TBC: spectrum allocations]
GBAS Data Link
The data link element of GBAS shall be operated in VHF, using a differential 8-phase shift keying (D8PSK) modulation scheme.
The portion of the spectrum that has been considered for the purposes of VHF GBAS is the navigation band currently occupied by the ILS and VOR (108 MHz - 117.975 MHz). It is proposed that the D8PSK data link be designed such that it can fit on 25 kHz channel spacing, allowing the GBAS to be slotted between VOR allocations. The GBAS uses the same D8PSK modulation scheme as VDL Mode 2 yet only operates in the ground data broadcast mode.