Downlink performance of different soft handover algorithms in 3G multi-service environments

As a crucial technology for seamless communication, soft handover has been investigated in the literature since the emergence of CDMA.. In this paper, triggered by the asymmetric features of 3G Internet and multimedia services, the downlink performances of four typical soft handover algorithms: distance-based, IS-95A, UTRA soft handover algorithms and SSDT are evaluated and compared under various multi-service environments. Results show that the performance of different algorithms in terms of downlink information capacity depends closely on the soft handover overhead. It is also sensitive to the multi-service structure and the radio parameters such as shadow fading. By choosing proper soft handover algorithm and overhead, the downlink capacity can be improved.