Specification and test of a mobile data system

Specifying and testing a land-mobile-radio system to be used for data communications presents a series of problems to the user and to the designer. The probability of a successful message transaction from any point in the coverage area is a function of the length of the message, the number of attempts allowed and the bit-error-rate (BER) on the channel. The traffic which can be supported by the channel is a function of the same parameters in addition to contention on the mobile-to-base portion of the communications link. Testing of the coverage can be accomplished by selection of test points, identification of the length of the test message and determination of the allowed number of attempts. Busy hour traffic which can be supported by the channel is simulated by computer programs and in a live environment. This paper presents the specification and test of the Los Angeles Police Department mobile data system.