1、 INTERNATIONAL TELECOMMUNICATION UNION CCITT Series GTHE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE Supplement 30(11/1988) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS TRANSMISSION PLAN ASPECTS OF LAND MOBILE TELEPHONY NETWORKS Reedition of CCITT G Series
2、Recommendation Supplement 30 published in the Blue Book, Fascicle III.1 (1988) NOTES 1 CCITT G-series Recommendation Supplement 30 was published in Fascicle III.1 of the Blue Book. This file is an extract from the Blue Book. While the presentation and layout of the text might be slightly different f
3、rom the Blue Book version, the contents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below). 2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized ope
4、rating agency. ITU 1988, 2007 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Fascicle III.1 Supplement 30 1 Supplement No. 30 TRANSMISSION PLAN ASPECTS OF LAND MOBILE TELEPHONY NETWORKS Draft Recommendation G.
5、173 (This Supplement is proposed for study during the present study period with the aim to convert it into a Recommendation.) 1 General This Recommendation is primarily concerned with the special planning aspects which pertain to analogue or digital land mobile systems. Such systems, due to technica
6、l or economic factors, will prevent a full compliance with the general characteristics of international telephone connections and circuits recommended by CCITT. The scope of this Recommendation is thus to give guidelines and advice to Administrations as to what kind of precautions, measures and mini
7、mum requirements which are needed for a successful incorporation of such networks in the national PSTN. The performance objectives of such systems may vary between different groups of customers. For normal customers the objective should be to reach a quality as close as possible to CCITT standards.
8、For other groups of very disciplines customers other performance objectives might be acceptable. 2 Network configurations Under study. Under this headline Administrations should be advised to use 4-wire transmission to avoid problems when accessing inherently 4-wire mobile links. 3 Nominal transmiss
9、ion loss of mobile links Under study. Under this headline the problems with the application of loudness ratings and the correct loading of the radio channels should be discussed. The recommended LR values in CCITT Recommendation G.121 are not directly applicable due to the fact that the background n
10、oise level is higher in a car than what is assumed in Recommendation G.121. What is the design objective for the speech levels from the radio path and what levels should be delivered to the network? 4 Stability Under study. 5 Echo Under study. Under this headline the need for echo control devices sh
11、ould be discussed. 6 Noise Under study. (Can the European group give indications of the inherent noise performance of the codec algorithms being considered?) 2 Fascicle III.1 Supplement 30 7 Delay Under study. 8 Effects of errors in digital systems Several coding methods, such as SBC, ATC, RELP and
12、APC-AB with transmission bit rates 16 kbit/s have been proposed to achieve spectrum utilization efficiency and quality comparable with conventional analog FM systems. However, the application of such highly efficient speech coding methods to land mobile radio can lead to a significant degradation in
13、 quality because of transmission errors. Mobile radio links are not always error-free. Burst errors occur frequently due to multipath fading. It has been reported that the average bit error rate (BER) performance of diversity reception is 10-2-10-4in the 10 to 20 dB range of the average carrier to n
14、oise power ratio (CNR), and burst error length reaches 20 to 100 bits in case of 16 kbit/s digital signal transmissions. Therefore, robustness against burst error is an important characteristic for speech coding applied to mobile communication. Speech CODECs in mobile radio links should involve erro
15、r control techniques so as to provide robustness in multipath fading channels. Thus, the transmission bit rate includes redundancy bits for error control. Concerning quality evaluations, it may be better to use the average CNR as the receiving level for comparisons among analogue and digital systems
16、. This is because it can present the receiving level as a normalized unit for both analog FM and digital systems. In quality evaluations between digital systems, the average signal energy per bit to noise power density ratio (Eb/No) is suitable for the presentation of the receiving level. This is be
17、cause it can describe the receiving level as a normalized unit for any transmission bit rate and receiving bandwidth. 9 Quantizing distortion Under study. 10 Effect of transmission impairments on voiceband data performance Under study. ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, D
18、IGITAL SYSTEMS AND NETWORKS For further details, please refer to ITU-T List of Recommendations. INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS General definitions G.100G.109 General Recommendations on the transmission quality for an entire international telephone connection G.110G.119 General char
19、acteristics of national systems forming part of international connections G.120G.129 General characteristics of the 4-wire chain formed by the international circuits and national extension circuits G.130G.139 General characteristics of the 4-wire chain of international circuits; international transi
20、t G.140G.149 General characteristics of international telephone circuits and national extension circuits G.150G.159 Apparatus associated with long-distance telephone circuits G.160G.169 Transmission plan aspects of special circuits and connections using the international telephone connection network
21、 G.170G.179 Protection and restoration of transmission systems G.180G.189 Software tools for transmission systems G.190G.199 INTERNATIONAL ANALOGUE CARRIER SYSTEM GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS Definitions and general considerations G.210G.219 General Rec
22、ommendations G.220G.229 Translating equipment used on various carrier-transmission systems G.230G.239 Utilization of groups, supergroups, etc. G.240G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES Carrier telephone systems on unloaded symmetric cable pair
23、s, providing groups or supergroups G.320G.329 Carrier systems on 2.6/9.5 mm coaxial cable pairs G.330G.339 Carrier systems on 1.2/4.4 mm coaxial cable pairs G.340G.349 Additional Recommendations on cable systems G.350G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-R
24、ELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES General Recommendations G.400G.419 Interconnection of radio-relay links with carrier systems on metallic lines G.420G.429 Hypothetical reference circuits G.430G.439 Circuit noise G.440G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPH
25、ONY Radiotelephone circuits G.450G.469 Links with mobile stations G.470G.499 TESTING EQUIPMENTS TRANSMISSION MEDIA CHARACTERISTICS General G.600G.609 Symmetric cable pairs G.610G.619 Land coaxial cable pairs G.620G.629 Submarine cables G.630G.649 Optical fibre cables G.650G.659 Characteristics of op
26、tical components and subsystems G.660G.699 Printed in Switzerland Geneva, 2007 ITU-T RECOMMENDATIONS SERIES Series A Organization of the work of the ITU-T Series B Means of expression: definitions, symbols, classification Series C General telecommunication statistics Series D General tariff principl
27、es Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital netwo
28、rk Series J Transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M TMN and network maintenance: international transmission systems, tel
29、ephone circuits, telegraphy, facsimile and leased circuits Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching
30、and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks and open system communications Series Y Global information infrastructure and Internet protocol aspects Series Z Languages and general software aspects for telecommunication systems
