AMCP/WGC-WP/10

4 October 2000

AERONAUTICAL MOBILE COMMUNICATIONS PANEL

Working Group C

FIRST MEETING

Montreal, Canada

22 – 30 March 2000

Agenda Item 6:Review of the Annex 10 radiotelephony procedures

REVIEW OF ANNEX 10 RADIOTELEPHONY PROCEDURES

Presented by Brent Phillips

Prepared by Dave Sim & Andy Pickens

AMCP WG-A/15 WP-617

1999 09 09

Aeronautical Mobile Communications Panel (AMCP)

Working Group A, Meeting No. 15

Toulouse, France

September 14-24, 1999

Agenda Item 9:Review of Annex 10 Radiotelephony Procedures

Prepared by Dave Sim & Andy Pickens

1. Introduction

1.1 This paper presents an update of material previously presented in WP-482 at AMCP WG-A/11, in response to AMCP/6 task CNS-7402: Review Annex 10 radiotelephony procedures to include AMS(R)S and digital communications.

1.2 It had been noted at the tenth meeting of WG-A, in WP-471, that Annex 10, Volume II, contains SARPs and procedures for aeronautical telecommunications which do not reflect the introduction of data link communications in Annex 10.

1.3 The WG agreed at that time, and again at AMCP/6 to review Annex 10, and to develop proposed amendments, as appropriate, by 2000.

2. Discussion

2.1 Several paragraphs of Annex 10 were identified in WP-471 presented by the Secretariat where amendments could be considered in order to reflect new technologies used for air-ground data link communications, including AMSS voice communications.

2.2 The appendix to this paper includes those considerations that were developed by the Secretariat and proposed text that may be reviewed for inclusion in the Annex.

2.3 Each consideration is addressed and in some cases amendments to the text are proposed. In keeping with ICAO practices, new text is highlighted and removed text is struck through.

3. Action

3.1 The meeting is invited to consider the material presented in the appendix for further discussion.

Appendix

Proposed amendments to Annex 10, Volume II

A.1 Considerations (WP-471):

  1. Add new text which will present to the reader an indication that the provisions apply to all forms and types of aeronautical communications, including satellite communications.
  1. Add definition for aircraft earth station and ground earth station.
  1. Add *(R) Route.

Proposals:

  1. In the Introduction, at the end of the first paragraph, add the following:

Telecommunications in Annex 10 refers to the exchange voice and data information between aircraft, between ground stations, and between aircraft and ground stations, utilizing analog and digital techniques. Among the digital systems are the High Frequency Data Link (HFDL), the Very High Frequency Digital Link (VDL), the Aeronautical Mobile Satellite Service (AMSS), the Microwave Landing System (MLS) data link and the Secondary Surveillance Radar Mode Select (SSR Mode S) data link . Among the analog systems are the High Frequency and Very High Frequency voice services.

  1. In 1.2 Stations, add the following definitions (that also appear in Volume III, Part I):

Aircraft earth station (AES). A mobile earth station in the aeronautical mobile-satellite service located on board an aircraft (see also “GES”).

Ground earth station (GES). An earth station in the fixed satellite service, or in some cases, in the aeronautical mobile-satellite service, located at a specified fixed point on land to provide a feeder link for the aeronautical mobile-satellite service (see also “AES”).

Note. - This definition is used in the ITU’s Radio Regulations under the term “aeronautical earth station.” The definition herein as “GES” for use in the SARPs is to clearly distinguish it from an aircraft earth station (AES), which is a mobile station on an aircraft.

  1. In 1.1 Services, after the definition for Aeronautical mobile (R) service, add the following note:

Note. - (R) means Route

A.2 Consideration:

Consider the need for a definition for data link communications (as proposed by ADSP), “Data link communications are intended for the exchange of messages via data link.”

Proposal:

In 1.3 Communications methods add the following definition:

Data link communications. The exchange of digital data between aircraft, between ground stations, and between aircraft and ground stations by means of satellite, air-ground radio, and terrestrial networks.

A.3 Consideration:

Consider the need for a definition of “channel” (in view of the introduction of 8.3 kHz spacing and the variance between frequency and channel).

Proposal:

In 1.7 Miscellaneous add the following definition (that also appears in Volume V):

Frequency channel. A continuous portion of the frequency spectrum appropriate for a transmission utilizing a specified class of emission.

Note. - The classification of emissions and information relevant to the portion of the frequency spectrum appropriate for a given type of transmission (bandwidth) are specified in the Radio Regulations, Article 4 RR 264 to RR 273 inclusive.

A.4 Consideration

Consider the addition of a definition for HFDL, VDL.

Proposal:

In 1.1 Services add the following definition:

High frequency data link (HFDL). An aeronautical mobile (R) service in the aeronautical mobile HF frequency band 2.8 - 22 MHz, between aircraft stations and aeronautical stations, reserved for digital data communications relating to safety and regularity of flight primarily along major world air routes and regional and domestic air routes. The HFDL is a constituent mobile subnetwork of the aeronautical telecommunications network (ATN) which may in addition provide non-ATN functions such as, for instance, data link service (DLS).

Note. - HFDL frequencies and operating areas are defined in the Appendix 27 Aer2 to the Radio Regulations.

In 1.1 Services add the following definition (which includes some existing text from Volume III, Part I):

VHF digital link (VDL). An aeronautical mobile (R) service in the aeronautical mobile VHF frequency band 117.975 - 137 MHz, both between aircraft stations and between aircraft stations and aeronautical stations, reserved for digital data communications relating to safety and regularity of flight. The VDL is a constituent mobile subnetwork of the aeronautical telecommunications network (ATN) which may in addition provide non-ATN functions such as, for instance, digitized voice.

A.5 Consideration

Consider the addition of “ 3) Aeronautical Mobile Satellite (R) Service” in paragraph 2.1 Division of service.

Proposal:

Reject this consideration. The AMS(R)S is a subset of the aeronautical mobile service (AMS) which is already listed in 2.1, 2) aeronautical mobile service. In addition to the AMS(R)S, the AMS includes the AM(R)S in various frequency bands.

A.6 Consideration

Confirm the validity of the Recommendation in paragraph 2.2 Telecommunications - charges, within the AMS(R)S environment.

Recommendation. - The exchange of communications necessary for ensuring safety of air navigation and the regularity of air traffic between aeronautical fixed stations of different States and between aeronautical stations and aircraft stations should be handled without specific message charge unless otherwise provided.

Proposal:

In 2.2 Telecommunications - charges, add after the recommendation:

Note. - Where a cost per message has been established in lieu of, or in addition to, a cost for service, this message cost may be recovered from telecommunications service users.

Further discussion:

In the report of the second meeting of the ATN Panel, 4-15 November 1996, the report on Agenda Item 3, Appendix B - Draft Detailed SARPs, Sub-Volume V, Internet Communications Service, states, in Paragraph 5.3.5.2.2.2 Emergency Use of a Mobile Subnetwork:

5.3.5.2.2.2.1 In the case of Air-Initiated Mobile Subnetworks, an Air/Ground Router shall not refuse a Call Indication or refuse to establish a BIS-BIS connection with an ATN Airborne Router, when a Call Indication from the ATN Airborne Router is received less than 5 minutes after a Call Indication was rejected, or a call was terminated by Systems Management.

5.3.5.2.2.2.2 The Air/Ground Router shall permit, through the implementation of an appropriate routing policy, the use of a so established connection for emergency and distress data.

Note. - This situation arises when the Airborne Router has no other Air/Ground connectivity, and refusal to accept a connection may cause a safety hazard. An Air/Ground Router may limit the use of such connections through routing policy, or permit full access, as a local matter.

In order to address the need for communications where local administrative or commercial arrangements could restrict the use of a communications sub-network to delinquent or non-customers, the following paragraph is proposed:

Proposal:

Add the following paragraph:

2.2.1 Where charges for messages or telecommunications services have been established, no message relating to the safety of air navigation or the regularity of air traffic shall be rejected by any telecommunications service provider based on an inability or unwillingness by the service user to remit payment.

A.7 Consideration

Review the wording of paragraph 3.3.1 .

3.3.1 Only those messages coming from within the categories specified in 4.4.1.1 shall be accepted for transmission by the aeronautical telecommunication service.

4.4.1.1 Categories of messages. Subject to the provisions of 3.3, the following categories of message shall be handled by the aeronautical fixed telecommunication network:

a) distress messages;

b) urgency messages;

c) flight safety messages;

d) meteorological messages;

e) flight regularity messages;

f) aeronautical information services (AIS) messages;

g) aeronautical administrative messages;

h) service messages.

The reference to categories of messages in 4.4.1.1 are for AFTN only. Should reference to AMS and AMSS be included?

Further consideration:

In paragraph 5.1.8, message categories are again discussed in relation to the aeronautical mobile service for voice telephony. Are the six categories and order of priority valid in AMS(R)S and data link communications?

5.1.8 Categories of messages.

The categories of messages handled by the aeronautical mobile communications service and the order of priority in the establishment of communications and the transmission of messages shall be in accordance with the following table.

a) Distress calls, distress messages and distress traffic

b) Urgency messages, including messages preceded by the medical transports signal

c) Communications relating to direction finding

d) Flight safety messages

e) Meteorological messages

f) Flight regularity messages

Discussion:

The aeronautical mobile satellite (R) service and other mobile and mobile (R) services such as HFDL and VDL are sub-sets of the aeronautical mobile service. The aeronautical fixed telecommunication network is a subset of the aeronautical fixed service. All of these are elements of the overall aeronautical telecommunication service.

Volume III, Part I, Chapter 3 (ATN SARPs), Table 3-3 lists the mapping of network priority to mobile subnetwork (AMSS, VDL Mode 1 & 2, SSR Mode S) priority for the Aeronautical Telecommunication Network (ATN). This same map is included in the Manual of Technical Provisions for the Aeronautical Telecommunication Network (Doc 9705-AN/956) in Table 1-3.

The Manual of Technical Provisions for the ATN also discusses subnetwork priority:

5.2.8.5.1.1 When an ATN connection mode subnetwork does not support prioritisation on subnetwork connections, then the ATN Internet Entity shall not attempt to specify a subnetwork connection priority, and NPDUs of any priority may be sent over the same subnetwork connection.

5.2.8.5.1.2 When an ATN connection mode subnetwork does support prioritisation of subnetwork connections, then unless the relationship between ATN Internet Priority and subnetwork priority is explicitly specified by the subnetwork specification, the following shall apply:

a)Subnetwork connections shall be established as either “High” or “Low” priority connections.

b)For the “Low” priority connection type, the priority to gain a connection, keep a connection and for data on the connection shall be the defaults for routine use of the subnetwork.

c)“High” priority connections shall be used to convey NPDUs of priority ten and above. “Low” priority connections shall be used to convey all other NPDUs.

Note. - The above does not apply to the AMSS Subnetwork, which has specified its own priority mapping scheme.

Volume III, Part I, Chapter 4 (AMSS SARPs), Paragraph 4.2.1.1 addresses categories and priorities of messages in the AMS(R)S bands. Table 4.26 lists subnetwork connection priority mapping.

The HFDL SARPs, contained in Amendment 74 to Annex 10, applicable November 4, 1999, to be included in Volume III, Chapter 11, make indirect reference to message priorities in 11.2.6 Quality of service for priorities 7 through 14. There is, then, acknowledgment of categories but no mechanism for handling priorities.

The VDL SARPs do not include a provision for message categories and priorities.

The International Radio Regulations also assign priorities for various categories of messages. These are included in Article S44.1.

Message categories and priority definitions should be considered at the level of the aeronautical telecommunication service, and refined as necessary for each specific service.

Proposal:

Consolidate available information from the references in the Discussion and develop a comprehensive matrix of message types, priorities, and the services supported by each mobile sub-network as below. Include this material in Volume II, Chapter 3 - General Procedures.

AMCP WG-A/15 WP-617

1999 09 09

Comparison of Priority Structures Among Regulations, Requirements and Systems

Radio Regulations Order of Priority - aeronautical mobile and aeronautical mobile-satellite services (Note 2) / Radiotelephony
Priority Order
(ICAO Annex 10 Volume II, Ch. 5) / Aeronautical Fixed Service Priority Order
(ICAO Annex 10, Volume II, Ch. 4) / ATN Message categories – data
(priority level numbers defined for the CLNP) / ATN
applications / AMSS SNC level
data priority order
(Annex 10, Vol. III, Ch.4) (Note 4) / AMSS
Ckt-Mode (Voice) Priority / SSR Mode S priority / VDL
Mode 1 & 2 priority / HFDL
priority
(Note 3)
14 - Network/systems management / [14] Distress Communications, Urgent Communications, and Network/Systems Management / 1
SARPs:
Distress and Urgency
[MOPS/MASPS:
Distress, Urgency] / high / not applicable / high
1 - Distress calls, distress messages & distress traffic / [a] Distress calls, distress messages and distress traffic / [a] Distress messages / 13 - Distress communications / not applicable
2 - Communications preceded by the urgency signal / [b] Urgency messages, including messages proceeded by the medical transports signal / [b] Urgency messages / 12 - Urgent communications / not applicable
3 - Communications relating to radio direction finding / [c] Communications relating to direction finding / (not defined) / (not defined) / [11] Flight Safety Messages and Communications Relating to Direction Finding / 2
SARPs:
Flight Safety
[MOPS/MASPS:
Direction Finding, Flight Safety] / not applicable
4 - Flight safety messages / [d] Flight safety messages / [c] Flight safety messages / 11 - High-priority flight safety messages / CPDLC / ADS / not applicable
10 - Normal-priority flight safety messages / AIDC / high
5 - Meteorological messages / [e] Meteorological messages / [d] Meteorological messages / 9 - Meteorological communications / [8] Meteorological Communications / 3
SARPs:
Regularity and meteorological
[MOPS/MASPS:
Other Safety & Regularity of Flight] / low / not applicable / low
6 - Flight regularity messages / [f] Flight regularity messages / [e] Flight regularity messages / 8 - Flight regularity communications / CM / ATSMHS / [7] Flight Regularity Communications / not applicable
(not defined) / (not defined) / [f]Aeronautical information services / 7 - Aeronautical information service / ATIS / [6] Aeronautical Information Service Messages (NOTAMs, ATIS, etc.) / not applicable
(not defined) / (not defined) / (not defined) / 6 - Network/systems administration / [5] Aeronautical Administrative Messages and
Network/Systems Administration / not applicable
(not defined) / (not defined) / [g] Aeronautical administrative messages / 5 - Aeronautical administrative messages / not applicable / not applicable
(not defined) / (not defined) / [h*] Service message *priority as appropriate" (see Note 6) / 4 - <unassigned> / (see Note 6) / [see Note 6] / [see Note 6] / not applicable / [see Note 6]
7 - Messages relating to the application of the United Nations Charter / (not defined) / 3 - Urgent-priority administrative and U.N. Charter communications / [3] Urgent Priority Administrative and
UN Charter Communications / 4
SARPs:
Public Correspondence
[MOPS/MASPS:
Non-Safety & Regularity of Flight, Private & Public Correspondence] / not allowed / not applicable / not allowed
8 - Government messages for which priority has been expressly requested / (not defined) / (not defined) / 2 - High-priority administrative and State/Government communications / [2] High Priority Administrative and
State/Government Communications / not applicable
9 - Service communications relating to the working of the telecommunication service or to communications previously exchanged / (not defined) / (not defined) / 1 - Normal-priority administrative / [1] Normal Priority Administrative / not applicable
10 - Other aeronautical communications / (not defined) / (not defined) / 0 - Low-priority administrative / [0] Low Priority Administrative / not applicable
[Public Correspondence, AAC & APC; beyond scope of this def.] / (beyond scope) / (beyond scope) / ?? / ?? / (see Note 7) / not applicable

Notes:

  1. Priorities above the bold line are for communications related to safety and regularity of flight; those below, for "non-safety" communications (including AAC and APC).
  1. Reference ITU RR Article S44.1. Not all message categories and priorities defined by the ITU are matched by the ATN and its subnetworks. Priorities 1-6 are regarded as "safety communications".
  1. ATN priority level numbers are defined at the CLNP. It is a task of the SNDCF to map these to the particular subnetwork's priority structure, including recognition of invalid codes.
  1. Some AMSS subnetworks reserve particular internal link-layer priority codes for circuit-mode signaling and other purposes. Otherwise, the link layer and SNC level codes map 1:1.
  1. Applicable November 4, 1999. The HFDL does not include a definition of categories and priorities of messages, but does specify transfer delay times for two groups of messages priorities. Accordingly, this chart presents HFDL high priority for ATN priorities 11 through 14 and HFDL low priority for ATN priorities 7 through 10.
  1. AFS (AFTN) exemplified messages in this category as being inquiries about previous messages, which would be assigned a priority indicator the same as that of the message being inquired about. Therefore, there is no fixed priority level for these messages; if they exist in a given service, they are to be handled at the level of the related message category which can range between (a) and (g).
  1. RTCA MOPS and MASPS add "(AAC/APC)" to the category definitions. For AMSS SARPs, public correspondence is explicitly defined in the circuit-mode structure, but not in the packet-mode structure. Suggest adding "and public correspondence" to "[0] Low Priority Administrative".

AMCP WG-A/15 WP-617

1999 09 09

A.8 Consideration

Review wording of paragraphs 3.3.7 and 3.3.7.1 . Should reference to AMSS be added?

Proposal:

Reject the consideration.

These paragraphs discuss message transmission between aircraft using the aeronautical mobile service and the aeronautical fixed telecommunication network, or other aeronautical fixed service. The aeronautical mobile satellite service is a subset of the aeronautical mobile service, and is included by implication in these standards. The same is true for the other aeronautical mobile sub-networks.