System performance analysis with error-controlled data in a voice/data DS-CDMA system

In this paper, we analyze the effect of adopting an ARQ protocol in a voice/data DS-CDMA system. Basically, we consider the IS-95 type reverse link DS-CDMA system which supports two kinds of services, traditional voice and data services. This system includes a 1/3 rate convolutional code for FEC and shortened binary CRC codes for ARQ. First, we find the optimum ARQ code rate which maximizes the number of concurrent users. Average packet transmission time and the normalized system throughput are analyzed for various ARQ protocols. The analysis results show that the number of concurrent users is maximized when the ARQ code rate is about 0.935 and the total system throughput is optimized when the ARQ code rate is about 0.97.