1、ITU-T RECP!N*F*LL#L 94 I 4862591 0592364 477 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU OPERATIONS AND QUALITY OF SERVICE MOBILE SERVICE F.141 (06/94) INTERNATIONAL TWO-WAY MULTIPOINT TELECOMMUNICATION SERVICE VIA SATELLITE ITU-T Recommendation F.141
2、(Previously “CCITT Recommendation”) ITU-T RECMN*F.L4L 94 M 48b259L 05923b.5 303 = FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (IT). The -T is responsible for studying technical, operating and tariff questions and iss
3、uing Recommen- dations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the IT-T Study Groups which, in their turn, produce Recommendations on
4、 these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki. March 1-12, 1993). ITU-T Recommendation F.141 was prepared by IT-T Study Group 1 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure
5、 on the 1st of June 1994. NOTE In this Recommendation, the expression ?Administration? is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1994 All rights reserved. No part of this publication may be reproduced or utilized in any form
6、or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the IT. CONTENTS 1 scope Definition of service . 2 Service description . 2.1 Functional elements of service provision . 2.2 Service provision 2.3 Types of service 2.4 Area of service I
7、 . 1 2.5 Service configuration 3 Quality of Service 4 Service availability . 5 Class of space segment capacity Recommendation F.141 (W94) Page 1 1 1 1 1 1 1 2 3 3 3 i SUMMARY This Recommendation provides service and operational guidelines for the provision of international two-way multipoint telecom
8、munication service via satellite. International two-way multipoint telecommunication service via satellite is defined as a service provided to customers by Recognized Operating Agencies (ROAS) for the two-way transmission of information via satellite, between a central facility and a multiplicity of
9、 points where transmiheceive earth stations are located. ii Recommendation F.141 (W4) Recommendation F.141 INTERNATIONAL TWO-WAY MULTIPOINT TELECOMMUNICATION SERVICE VIA SATELLITE (Geneva, 1994) 1 scope This Recommendation provides operational guidelines and a service description including quality o
10、f service requirements for international two-way multipoint telecommunication service via satellite. 1.1 Definition of service international two-way multipoint telecommunication service via sateHite is defined as a service provided to customers by Recognized Operating Agencies (ROAs) for the two-way
11、 transmission of information via satellite, between a central facility and a multiplicity of points where transmit/receive earth stations are located. 2 Service description 2.1 Functional elements of service provision An international two-way multipoint telecommunication service via satellite genera
12、lly includes the following nine elements (see Figure 1): i ) 2) the customer central facility equipment; the links between the customer central facility equipment and the service provider command and control management centre; the service provider command and control management centre; the link betw
13、een the master earth station and the service provider command and control management centre; the master earth station (hub); 3) 4) 5) 6) the space segment capacity; 7) 8) 9) the user terminal equipment. the remote earth station antennas; the link between transmitheceive remote earth station antenna
14、and user terminal equipment; 2.2 Service provision The service may be provided on either a full-time (24-hour) basis, a scheduled part-time basis or an occasional basis. Where the hub and one or more of the remote earth stations are in different countries, the provision of service is governed by the
15、 appropriate national and intemational regulations and subject to agreement between the ROAs. The ROA in each country should be made aware of their scope of the service coverage and the traffic routing capabilities. 2.3 Types of service The service may be digital or analogue, provided in the form of
16、 inbound (remote to hub) and outbound (hub to remote) channels at rates depending on the application and within the capacity available. The data rates, bandwidths, and frequencies of the outbound channels and those of the inbound channels may be different. Recommendation F.141 (W94) 1 2.4 Area of se
17、rvice The service may be provided on a national and/or international basis in accordance with relevant national regulatory requirements. 2.5 Service configuration 25.1 way multipoint telecommunication service via satellite. As illustrated in Figure 1, there are generally nine functional elements in
18、the provision of an international two- I I IO 1 I I I I I I I I I i I I l I I I I I I I I I I I I I I I l I L r I I I I I L II I I FIGURE 1E.141 Memational twcway miltipant tdeconaunicaion service via satellite 2.5.2 account the regulations governing the operation of the space segment providers and
19、ROAS involved. Owing to the need for flexibility, the service may be adapted to meet a variety of requirements taking into 2.5.3 a customers private network and/or by other arrangements designed to meet specific customer requirements. Subject to national regulatory arrangements, interconnection may
20、be offered with the public switched network, 2.5.4 The two-way operation is in a star configuration enabling communications between several remote locations and the hub, and communications among remote locations through the hub. The two-way operation can be achieved under proven multiple access proc
21、edures, such as those defined in G-. M-, and N-Series Recommendations. 2.5.5 The master hub, consisting of a master earth station and a service provider command and control management centre, may be dedicated to a single customer or may be shared by a number of customers; it may be located either on
22、 a customers site or may be remotely connected. 2 Recommendation F.141 (06.44) 2.5.6 provider command and control management centre (3) and the links (2.4) are a national matter. The conditions for use of the master earth station (5). the remote transmit/receive earth stations (7), the service 2.5.7
23、 providers. The conditions for the use of the space segment capacity (6) are defined by the satellite system space segment 2.5.8 equipment; but the user equipment may also be remotely connected by a link (8) to the transmitheceive earth stations. The remote transmitheceive earth stations (7) would n
24、ormally be located at the user premises near the user 3 Quality of Service I The efficiency of operation and therefore the quality of service provided to the customers are linked to the relationship of all parties which contribute to the provision of the service, i.e. the technical equipment and the
25、 entities in charge of the operation. 4 Service availability The service availability, as definel in CCMT Recommendation X.140, is the ratio of aggregate time, during which satisfactory or tolerable service is or could be provided, to the total observation period. Service availability depends on the
26、 class of space segment capacity, the earth station configuration and interference effects, and the bit error rate required. It is not possible to specify a service availability requirement for all two-way multipoint telecommunication services implementations via satellite. The availability for each
27、 implementation will have to be calculated on an individual basis considering all the points mentioned above. 5 Class of space segment capacity Services offered may take account of classes of space segment capacity available from the space segment provider. The following classes of space segment cap
28、acity may be utilized to provide services: a) Non-pre-emptible - A service which may not be interrupted or terminated for the provision of a service to another customer. There are two types of non-pre-emptible services: 1 ) protected - A service for which restoration is guaranteed; and 2) unprotected - A service for which restoration is not guaranteed and which may only be restored subject to availability of an alternate facility. b) Pre-emptible - A service which may be interrupted to provide a service of higher priority. Recommendation F.141 (06/94) 3 Printed in Switzerland Geneva, 1994
