Call performance in a frequency reuse digital portable radio system

A discrete-event stochastic simulation of many concurrent calls was used to generate signal-to-interference ratio (S/I) time histories and statistics on a time-division multiple-access (TDMA) uplink. The simulation integrates portable radio multiple access, uplink/downlink signal modeling, and the traffic process. Calls were held to completion, enabling observation of the effects of cochannel interference on time-dependent S/I statistics. It was found that the improvement obtained from measurement-based time-slot assignment in uplink S/I at access partially erodes over the life of a call, if it retains the time-slot assigned at the start. The amount and speed of erosion of S/I at the first percentile suggests that good transmission quality can be maintained for stationary users, with low overhead in the fixed radio network.<
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