1、CCITT RECMN*Me3340 92 = qBb2593 0578737 773 I NTE R NATI ON AL TE LEC0 M MU N IC AT1 ON U N I ON CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CON SU LTATI VE COM M ITT E E M.1140 (1 0/92) MAINTENANCE: MOBILE TELECOMMUNICATIONS SYSTEMS AND SERVICES MARITIME MOBILE TELECOMMUNICATION SERVICES VIA SA
2、TELLITE Recommendation M.1140 CCITT RECMN*M-LL40 92 Y862531 05787L8 b2T FOREWORD The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is responsible for studying technical, operating and tariff que
3、stions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approval of Recommendations by
4、the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). Recommendation M.1140 was prepared by Study Group N and was approved under the Resolution No. 2 procedure on the Sth of October 1992. CCIT NOTE In this Recommendation, t
5、he expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized private operating agency. O ITU 1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, inclu
6、ding photocopying and microfilm, without permission in writing from the ITU. CCITT RECMN*M*3340 92 4862593 0578739 566 1 2.1.5 ship earth station (SES) A ship earth station in the maritime mobile-satellite service is a mobile earth station which provides a 4-wire analogue interface for connection of
7、 a maritime satellite circuit to a maritime local system and a 4-wire circuit test access point. Recommendation M.1140 MARITIME MOBILE TELECOMMUNICATION SERVICES VIA SATELLITE (1 992) Abstract: This Recommendation describes general maintenance aspects of satellite maritime mobile systems predominant
8、ly based on INMARSAT-A maintenance requirements. Keywords: Satellite Maritime Mobile, Maintenance Aspects, INMARSAT-A. 1 Purpose The purpose of this Recommendation is to describe general maintenance aspects of satellite maritime mobile systems and define interrelationship and intenvorking issues of
9、such systems with terrestrial voice and data networks taking into consideration criteria, procedures and facility standards specified in the M- and O-Series Recommendations. This Recommendation is predominantly based on the maintenance requirements of the INMARSAT-A maritime satellite system which i
10、s the prevailing operational maritime service. Other maritime systems such as the digital INMARSAT-C, -B and -M will be addressed in Recommendations, specific to each type. However, the following sections are equally relevant to other INMARSAT maritime systems. 2 General maintenance aspects of satel
11、lite maritime mobile systems 2.1 Definitions 2.1.1 maritime mobile service via satellite Mobile service via satellite in which mobile earth stations are located on-board ships. This can include mobile earth stations on-board rescue vessels and radio buoys (or other devices) used to locate shipwrecks
12、, 2.1.2 maritime satellite system In the maritime mobile-satellite service, all of the temporary connections between a telephone at a ship earth station (SES) and the maritime virtual switching point at a coast earth station (CES) constitutes a maritime satellite system. It comprises a maritime sate
13、llite circuit and a maritime local system. The general arrangement is shown in Figure 1M.1140. 2.1.3 maritime satellite circuit Maritime satellite circuit is a 4-wire circuit between a maritime virtual switching point at a coast earth station and the 4-wire circuit test access point at a ship earth
14、station, via a satellite repeater. 2.1.4 maritime local system All the equipment between the 4-wire test circuit access point on a ship earth station and a 2-wire or 4-wire telephone served by that ship earth station constitutes a maritime local system. It may include 4-wire to 2-wire termination se
15、ts, echo control equipment, data interfaces, and 4- or 2-wire switching devices. Recommendation M.1140 (10/92) 1 CCITT RECMN*M.LLYO 92 4862593 0578720 288 International switching centre (W e mobile unit e.g. ship . -. -. -. -. Coast earth station (CES) (Note 4) iMi , ._ , -I I I I Ship earth station
16、 (SES) Maritime system I j + local LA Maritime satellite circuit LA I- b T W Signalling termination/conversion 4-wire test access fxt Switch % Optional switch L. I4 Maritime satellite system bl TO403080-92 IF Intermediate frequency (equipment) CP CTE Channel translating equipment RF Radio frequency
17、(equipment) MTT Maritime test terminal NCS Network coordination station M Network supervision and monitoring MVSP Maritime virtual switching point Channel processing (equipment) including signalling terminating equipment, etc. Noie 1 - A maritime virtual switching point should always be established
18、for transmission planning purposes. However, a switch at the coast earth station is optional. Note 2 - The actual frequencies used are 4/6 GHz (C-band) and 1.5/1.6 GHz (L-band). Noie 3 - Certain coast earth stations are also network coordination stations; their functions are described in 0 3.1.3 Noi
19、e 4 - Coast earth station functions are described in 0 4.1. Noie 5 - 4-wire test access point G is equivalent to 4-wire test access point F. FIGURE UM.1140 Constitution of a maritime satellite system (INMARSAT-A) 2.1.6 coast earth station (CES) A coast earth station in the maritime mobile-satellite
20、service is an earth station, which provides a 4-wire analogue interface for connection of a maritime satellite circuit to the international public switched telephone network. It also provides circuit test access points and test facilities. (See 4 4.1 for the functions of a coast earth station.) 2.1.
21、7 maritime test terminal (MTT) MTT is a ship earth station along with a maritime local system installed at a coast earth station and used for test purposes. 2.1.8 network coordination stations (NCS) A network coordination station in the maritime mobile-satellite service maintains a pool of frequenci
22、es, assigns frequencies on demand from a coast earth station for temporary use in a maritime satellite circuit, and supervises and monitors the use of the frequencies. The network coordination station is normally located at a coast earth station which is designated by the satellite system operator t
23、o fulfill these functions. (See 4 3.1.3 for the functions of a network coordination station.) 2 Recommendation M.1140 (10192) CCITT RECMN*M.LL40 92 4862593 0578723 334 2.1.9 coast earth station test position A coast earth station test position is used to originate test calls over the maritime satell
24、ite system to the maritime test terminal and to receive test calls from the maritime test terminai. 2.2 General maintenance principles 2.2.1 Responsibilities In an international connection which includes a ship earth station, the maritime satellite system may be regarded, from a transmission point o
25、f view, as analogous to a national network, and the maritime local system as analogous to a subscriber terminal within that network. Nevertheless, it should be noted that the maritime satellite circuit is set up between the coast earth station and the ship earth station on a demand assignment basis.
26、 Therefore, a coast earth station in the maritime satellite system may not have the direct responsibility for the maintenance of a particular maritime satellite circuit and a particular ship earth station all of the time. The operation and maintenance of the overall maritime satellite system is the
27、responsibility of the maritime satellite system operator, e.g. INMARSAT. The maintenance organization in each participating Administration is in general, responsible for the maintenance of the maritime satellite circuits. 2.2.2 Available services The maritime satellite systems in service provide tel
28、ex services to maritime mobile units in addition to telephone, facsimile and voice-band data services. When setting-up maintenance procedures, Administrations should consider the utilization of these services for communication, diagnostic and maintenance purposes, and should also consider that train
29、ed technical staff are generally available at the ship earth station only at the time the ship earth station is commissioned; however, the ship earth station is usually operated by a qualified radio officer who may be only able to assist in carrying out simple test procedures. Special services, high
30、 speed data services, and compressed video are being provided over the maritime satellite systems. The development of new maintenance procedures to support these services will be the subject of future study. 2.3 Interconnection with the international public switched telephone network Interconnection
31、 arrangements are considered with reference to Figure 1/M. 1140. The maritime virtual switching point at the coast earth station is considered to be the interface between test access points D and E (see Figure 2/M. 1140). The circuit between the international switching centre (ISC) and coast earth s
32、tation is considered as equivalent to an international public switched telephone circuit. 2.4 Lining-up and maintaining international public switched telephone circuits The circuit between the international switching centre and the coast earth station in Figure UM.1140 should be lined up and maintai
33、ned in accordance with those M-Series Recommendations appropriate to international public switched telephone circuits, e.g. Recommendations M.580 i and M.610 2. 2.5 Lining-up and maintaining maritime satellite circuits 2.5.1 Control, sub-control and respective responsibilities 2.5.1.1 General The as
34、signment of control and sub-control stations and respective responsibilities must address the configuration of the maritime satellite system. In every case a control station must be assigned for each circuit, and, in addition, sub-control stations are required for efficient maintenance. Recommendati
35、on M.1140 (lOD2) 3 CCITT RECMN*MmLL40 92 48b259L 0578722 050 = Coast earth station (CES) I +R dBr i (Note 1) -S dr 1 (Noie4) O dBr (Note 2) -3.5)dB MVSP 5.5dB -3.5 dBr -5.5 dBr (Noie 4) Ship earth station (SES) 1 l. I +R dBr i (Notes 4 and 5) - Maritime satellite circuit TO403090-92 Noie 1 - +R dBr
36、and 4 dBr in the coast earth station correspond to the levels +R dBm and 4 dBm using a modulation signal with a level of O dBmO. Note 2 - The levels of O dBr are given as an example. Note 3 - +R dBr and S dBr in the ship earth station correspond to the levels of +R dBm and S dBm using a modulation s
37、ignal with a level of O dBmO. Note 4 - See Figure 1/M.1140 for 4-wire test access points. Note 5 - The levels at test access point Fare those given in Recommendation G.473 3. Note 6 - For the abbreviations used in this figure see Figure 1/M.1140. FIGURE 2/M.1140 Levels at the coast earth station and
38、 ship earth station (INMARSAT-A) 2.5.1.2 Assignment of control stations The coast earth station will be the contra. station for the maritime satellite circuit. 2.5.1.3 Assignment of sub-control stations 2.5.1.3.1 In principle, the ship earth station should act as the maritime satellite circuit sub-c
39、ontrol station. However, the required staff and facilities may not be available to meet the circuit sub-control responsibilities, and special measures may need to be taken. 2.5.1.3.2 A maritime test terminal may be used to enhance fault location and maintenance in the maritime satellite system. In t
40、his regard the maritime test terminal may carry out some tests normally considered to be within the province of a sub-control station on behalf of a ship earth station. Whether or not a maritime test terminal should be assigned as a sub-control station is left for further study when the operation of
41、 a maritime test terminal is further defined. 2.5.1.4 Responsibilities of control and sub-control stations Control stations dealing with maritime satellite circuits should fulfill the responsibilities of control stations as defined in the M-Series Recommendations in general. The same will apply to s
42、ub-control stations. However, the maritime satellite systems present new concepts which require guidelines in as much as a maritime mobile unit is essentially a subscriber location (see 4 4.2.2). 2.5.2 Transmission characteristics The transmission design characteristics for maritime satellite circui
43、ts are given in Recommen- dation G.473 3. 4 Recommendation M.1140 (10D2) CCITT RECMN*M*3340 92 4862.593 0578723 T97 2700 to 3000 Hz 3000 to 3400 Hz The setting-up, lining-up and maintenance limits of the maritime satellite circuit between test access points E and F of Figure 2M.1140 should be as def
44、ined in Table 1N.1140 both for the case where no switch is located at the coast earth station and where a switch is located at the coast earth station. -1.2 to +4.4 -1.2. to not specified The attenuatiodfrequency limits in Table 1h.1140 are those which should be met with the compandors disabled. The
45、 measurements to be carried out with the compandors in circuit are a subject for further study. Idle noise The relative levels at the coast earth station and the ship earth station are shown in Figure 2h4.1140. - Not yet specified. See Annex A for further information. TABLE 1M. 1140 Provisional sett
46、ing-up, lini Transmission parameters Attenuation frequency relative to the attenuation at reference frequency I- Below 300 Hz 300 to 400 Hz 400 to 600 Hz 600 to 2400 Hz I 2400 to 2700 Hz n ig-up and maintenance limits Maintenance limits (dB) (See Note) Not specified -1.2 to +4.4 -1.2 to +2.6 -1.2 to
47、 +1.2 -1.2 to +2.6 2.5.3 Lining-up procedures 2.5.3.1 Measurement of the attenuation at the reference frequency The control station (coast earth station) sends a reference frequency form 4-wire test access E in Figure 2N.1140 at a level of -10 dBmO. The sub-control station (ship earth station) measu
48、res the level at 4-wire test access point F in Figure 2/M.1140 (the -5.5 dBr point). The receive level should be -15.5 dBm. The sub-control station (ship earth station) applies a reference frequency at the 4-wire test access F in Figure 2h4.1140 (the -3.5 dBr point) at a level of -13.5 dBm, i.e. -10
49、 dBmO. The control station (coast earth station) measures the level at the 4-wire test access point. This should be -10 dBmO at 4-wire test access point E in Figure 2hl.1140. The tolerance of the attenuation measurements shall be as specified in Recommendation M.580 i. Recommendation M.1140 (10B2) 5 2.5.3.2 Measurement of attenuatiodequency response The attenuation/frequency characteristic should be measured and recorded at the following frequencies to check that the limits contained in Table 1/M. 1140 are met: 420, 1020,2500,2800,3000 Hz. The attenuation/freque
