ITU-R QUESTION 37-55-2007 Digital land mobile systems for dispatch traffic《用于调度通信的数字陆地移动系统》.pdf

1、QUESTION ITU-R 37-5/5*Digital land mobile systems for dispatch traffic(1978-1982-1992-1995-1997-2007)The ITU Radiocommunication Assembly,consideringa) that the number of radio stations in the land mobile service is increasing very rapidly;b) that in several geographical areas the growing demand for

2、radio channels in the land mobileservice has resulted in a serious congestion in the frequency bands allocated to this service;c) that in order to alleviate this congestion as well as that expected in the future, it is desirablefor land mobile services to employ spectrum saving techniques;d) that im

3、proved spectrum efficiency might be achieved, taking into account essential systemcharacteristics like traffic density, grade of service, etc. and costs: by employing automatic techniques for the sharing of radio channels, for example by meansof trunking systems covering one or more radio zones; by

4、making an increased number of traffic channels available within a given bandwidth; by optimizing the size of base station coverage areas, to the traffic demand; by combining these techniques and others;e) that systems based on digital technology may offer a higher traffic capacity or improvedquality

5、 compared to analogue systems;f) that systems using digitally encoded speech transmission are being used widely;g) that the digital technology applied in such systems may require channel widths other thanthose used in the existing land mobile services;h) that systems based on digital technology offe

6、r a high degree of privacy and security;j) that these systems may provide services required by users of private mobile radio, publicaccess mobile radio and public safety services;k) that, particularly for systems operating in border areas of neighbouring countries, it isdesirable to reach internatio

7、nal agreement on certain system characteristics in order to come tomaximum usage flexibility,decides that the following Questions should be studied1 What are, with regard to frequency efficiency, the optimum characteristics of these systems,taking into account factors like system capacity, base stat

8、ion coverage area, complexity ofequipment, propagation factors and performance objectives?2 How can these systems meet the user demand and what are the operational requirements?_* Former Question ITU-R 37-5/8.- 2 -3 What are the services and facilities offered by these systems, which fulfil the spec

9、ificrequirements of users of private mobile radio, public access mobile radio and public safetyservices?4 What are the system parameters on which international agreement is desirable to ensurecompatibility between systems and/or operation of differing systems in neighbouring coverageareas?further decides1 that the results of the above studies should be included in one or more Recommendations,Reports or Handbooks;2 that the above studies should be completed by 2010.Category: S2