1、 Recommendation ITU-R M.1081-1(03/2012)Automatic HF facsimile and data systemfor maritime mobile usersM SeriesMobile, radiodetermination, amateurand related satellite servicesii Rec. ITU-R M.1081-1 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and
2、 economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are perform
3、ed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to
4、be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be foun
5、d. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radi
6、odetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management S
7、NG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2012 ITU 2012 All rights reserved. No part of thi
8、s publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R M.1081-1 1 RECOMMENDATION ITU-R M.1081-1Automatic HF facsimile and data system for maritime mobile users (1994-2012) Scope This Recommendation provides the automatic HF facsimile and data system f
9、or maritime mobile service using digital selective calling (DSC) messages; it specifically describes system characteristics and operational procedures for setting up calls and passing messages. These include the contents of DSC messages used to establish initial contact between the maritime mobile u
10、ser and gateway, protocols and structures of messages used to pass data over the working channel between the maritime mobile user and the gateway, and the characteristics of DSC and HF modems. The ITU Radiocommunication Assembly, considering a) the increasing importance of non-voice telecommunicatio
11、n services, e.g. high-speed data transfer and facsimile services; b) that maritime mobile users may be equipped with MF/HF radio equipment to satisfy the requirements of the GMDSS; c) that a high-speed data service over HF radio may be useful for updating Electronic Chart Display and Information Sys
12、tems (ECDIS); d) that vessels already use personal computers to run application software to manage ships stores, staff, etc.; e) that Article 52 of the Radio Regulations (RR) does not permit coast stations to emit identification or marking signals on idle radiotelephone working channels; f) that sys
13、tem compatibility is necessary for international operation, and that commonality is desirable to ensure that system cost per mobile user is minimized; g) that most ship stations are not able to simultaneously use their radio transmitter and receiver for duplex operation; h) that vessels equipped wit
14、h the global distress safety system (GMDSS) have fewer qualified radio operators with detailed knowledge of HF propagation operating the radio equipment; j) that the digital selective-calling (DSC) system described in Recommendations ITU-R M.493 and ITU-R M.541 can be used for signalling over the ra
15、dio path to enable common channels to be used for initial signalling purposes prior to transfer to a working channel; k) that the data transfer rate that can be achieved over the radio path is significantly lower than that which can be achieved over the PSTN, recommends 1 that the gateway which prov
16、ides the interface at the coast station between the radio and PSTN paths should include store-and-forward facilities; The Director, Radiocommunication Bureau, is invited to bring this Recommendation to the attention of the Telecommunication Standardization Sector and the International Maritime Organ
17、ization (IMO). 2 Rec. ITU-R M.1081-1 2 that the system characteristics and operational procedures for setting up calls and passing data messages, including facsimiles, between maritime mobile users and fixed users on the PSTN should be in accordance with Annex 1; 3 that the frequencies used for a ra
18、dio contact between a maritime mobile user and the gateway should be automatically determined by a frequency prediction program; 4 that calling channels should be used, employing digital selective-calling techniques based on the technical and operational characteristics in accordance with Recommenda
19、tion ITU-R M.493, for establishing the initial contact between the mobile user and the gateway; 5 that the transfer of the data (including facsimile images) should be conducted on working channels employing data modems specifically designed to cope with HF propagation characteristics and capable of
20、a user data rate, after error correction, on a typical HF telephony-bandwidth channel, of approximately 1 000 bit/s; 6 that the contents of the DSC messages used to establish the initial contact between the maritime mobile user and the gateway should be in accordance with Annex 2; 7 that the error c
21、orrecting protocol and structure of the messages that are used to pass data between the maritime mobile user and the gateway over the working channel should be in accordance with Annex 3; 8 that the operation of the maritime mobile users equipment should be simple and should not require detailed kno
22、wledge of HF radio propagation; 9 that the maritime mobile users equipment should be capable of receiving data messages during unattended operation; 10 that fixed users on the PSTN should be able to use their normal data and facsimile equipment as used for communication with other users on the PSTN;
23、 11 that data transmission over the working channel should have a very low residual error rate; 12 that the technical characteristics of the DSC and HF data modems should be in accordance with Annex 4; 13 that data compression techniques should be used on the data files transferred across the radio
24、path to reduce the amount of data to be transferred; 14 that the mobile users terminal should include an interface to a navigation system which provides on-line position information; 15 that the characteristics and procedures described in the annexes are equally applicable when the connection betwee
25、n the gateway and fixed users is via a Public Switched Data Network instead of via the PSTN. Rec. ITU-R M.1081-1 3 Annex 1 System characteristics and operational procedures for setting up calls and passing data messages 1 General 1.1 A typical configuration of a complete communication system is show
26、n in Figure. 1. 1.2 The gateway, through which all messages pass, is basically a store-and-forward message switch which provides an interface between the radio and PSTN message paths. The gateway communicates with maritime mobile users over the radio path and with fixed users over the PSTN. 1.3 To f
27、acilitate automatic calling of the mobile and to enable billing, all mobile and fixed users wishing to send messages should be registered on a database in the gateway. Mobile users should be identified by their name and unique nine-digit Maritime Mobile Service Identity (MMSI). Fixed users should be
28、 identified by their name and a ten-digit Personal Identification Number (PIN). The gateway checks the users MMSI or PIN number before allowing them to send messages into the gateway. The gateways database also maintains an up-to-date record of mobile users positions (see 2.1 and 3.2 below). 4 Rec.
29、ITU-R M.1081-1 FIGURE 1 Automatic HF facsimile and data system (typical configuration) M.1081-01MobileuserPCFaxDSCmodemHFmodemTX/RXMobileuserRadioCallset-uponDSC callingchannelFax/datacommunicationviaHFmodemonworkingchannelGateway(Coaststation)DSCmodems(6)DSCRX(6)HFRX(2)HFmodems(2)TX (2)Controlandme
30、ssageswitchFixeduser(PSTN)FaxPC/dataterminalRec. ITU-R M.1081-1 5 1.4 The call set-up over the radio path between the gateway and maritime mobile user terminal uses standard digital selective-calling techniques on the DSC calling channels allocated for public correspondence in the maritime mobile HF
31、 bands in a similar way to that for automatic MF/HF radiotelephony according to Recommendation ITU-R M. 1082. The gateway and mobile stations therefore need only to monitor a small number of DSC calling channels instead of all working channels when waiting for an incoming call. 1.5 The frequency ban
32、d to be used to make the initial contact between the maritime mobile user and the gateway is determined by a frequency prediction program which makes use of the date, time, positions of the mobile user and gateway, solar activity indices, propagation data and radio noise data to determine the best,
33、if any, of the frequency bands available. 1.6 Following the exchange of a DSC call and acknowledgement on the calling channel, both the mobile and the gateway establish contact on a working channel. This contact, and all further communication on the working channel, uses HF data modems designed in a
34、ccordance with Annex 4. 1.7 The contents of the DSC messages during calling and acknowledgement sequences by the mobile user and the gateway are described in Annex 2. 1.8 The messages passing over the working channel comprise command and data messages used within a protocol which controls the link a
35、nd passes data with minimum end-to-end residual errors. The command and data messages and the protocol used for a communication exchange on the working channel are described in Annex 3. 2 Mobile to gateway 2.1 When the mobile calls the gateway it indicates its position (latitude and longitude) in th
36、e DSC message. The gateways acknowledgement indicates the transmit and receive frequencies of the working channel to be used for subsequent communications and data transfer. 3 Gateway to mobile 3.1 When the gateway calls the mobile it indicates, in the DSC message, the transmit and receive frequenci
37、es of the working channel over which subsequent communications and data transfer will take place. 3.2 If the gateway wishes to call the mobile and the position of the mobile is not known or is more than six hours old, the gateway transmits a series of DSC ships position request calls sequentially on
38、 one DSC frequency in each of the HF bands. If no response is received from the mobile then, unless the mobile calls the gateway, the gateway repeats the position request calls six hours later. 4 Fixed user to gateway 4.1 The exact method for fixed users on the PSTN to access the gateway in order to
39、 send facsimile and data to mobile users may vary in different countries since it depends on the type of PSTN signalling system available and the method of routing the call in the PSTN. 4.2 An important consideration is to be able to automatically identify the telephone number of the fixed user for
40、billing purposes. 4.3 One method, which requires fixed users to be registered in advance at the gateway and requires the allocation of a PIN to each user, is outlined below. 6 Rec. ITU-R M.1081-1 4.4 Facsimile calls from fixed users on the PSTN to the gateway use a standard tone dialling telephone a
41、ssociated with a Group 3 facsimile machine to call an appropriate gateway telephone number. When the gateway answers the call, it uses a synthesized or pre-recorded voice message to prompt the fixed user for their PIN number and the MMSI(s) of the mobile users to which the facsimile is to be sent. T
42、he gateway validates the fixed users identity and checks whether the mobile users specified are registered on the gateway before instructing the fixed user to enter their facsimile and attempting any delivery. 4.5 Data calls from fixed users use a data terminal with a communication software package
43、and a suitable ITU-T V-series data modem to access the gateway. When the gateway answers the call, it uses screen messages to prompt the fixed user for their PIN number and the MMSI(s) of the mobile users to which the data messages are to be sent. The gateway carries out validation checks as for fac
44、simile messages. Annex 2 Contents of DSC messages used to establish initial contact between the maritime mobile user and the gateway 1 General The format of all DSC call and acknowledgement messages and the coding of the message fields complies with those detailed in Recommendation ITU-R M.493. A su
45、mmary of the messages used is given below. 2 DSC calling messages originated by mobile user and gateway acknowledgements Mobile calling message DSC field Dot pattern Phasing sequence Format specification Address Category Self-ID Message 1 Message 2 EOS Errorcheck tc-1 tc-2 Length 20 bits 6 DX, 8 RX
46、2 char 5 char 1 char 5 char 1 ch 1 ch 6 char 3 DX1 RX1 ch Content (symbol) 0101 etc. 125 DX 111-104 RX 123 123 GatewayMMSI 100 MobileMMSI 106 113 Position 117(RQ) Gateway acknowledgement message DSC field Dot pattern Phasing sequence Format specificationAddress Category Self-ID Message 1 Message 2 E
47、OS Errorcheck tc-1 tc-2 Length 20 bits 6 DX, 8 RX 2 char 5 char 1 char 5 char 1 ch 1 ch 6 char 3 DX1 RX1 ch Content (symbol) 0101 etc. 125 DX 111-104 RX 123 123 MobileMMSI 100 GatewayMMSI 106 113 Freqs 122(BQ) Rec. ITU-R M.1081-1 7 3 DSC calling messages originated by gateway and mobile acknowledgem
48、ents Gateway calling message DSC field Dot pattern Phasing sequence Format specificationAddress Category Self-ID Message 1 Message 2 EOS Errorcheck tc-1 tc-2 Length 200 bits 6 DX, 8 RX 2 char 5 char 1 char 5 char 1 ch 1 ch 6 char 3 DX1 RX1 ch Content (symbol) 0101 etc. 125 DX 111-104 RX 123 123 Mobi
49、leMMSI 100 GatewayMMSI 106 113 Freqs 117(RQ) Mobile acknowledgement message DSC field Dot pattern Phasing sequence Format specificationAddress Category Self-ID Message 1 Message 2 EOS Errorcheck tc-1 tc-2 Length 20 bits 6 DX, 8 RX 2 char 5 char 1 char 5 char 1 ch 1 ch 6 char 3 DX1 RX1 ch Content (symbol) 0101 etc. 125 DX 111-104 RX 123 123 GatewayMMSI 100 MobileMMSI 106 113 Position 122(BQ) 4 DSC position request messages originated by gateway and mobile acknowledgements Position request call DSC field Dot pattern Phasing sequence Format specificationAddress Category Self-ID
