Comparative downlink shared channel evaluation of WCDMA release 99 and HSDPA

In order to avoid downlink channelization code shortage, a DSCH has been specified for WCDMA Release 99 system, and has been designed for enabling high data rate packet transmission. Further, WCDMA Release 5 introduces HSDPA to realize higher speed data rate together with lower round-trip times. In this paper, the performance of the downlink shared channel of Release 99 and HSDPA systems has been presented and compared. The system level simulation results were obtained using a dynamic system simulator. The simulator includes all relevant radio characteristics, WCDMA/HSDPA functions, and realistic models of the downlink traffic generated by Web browsing users. The results show that the HSDPA concept provides a 200% higher capacity gain than Release 99 DSCH and it goes to triple the service throughput when system load is increased. Moreover, the HSDPA concept offers outstanding improvement in the packet call throughput and also significantly reduces the packet call transfer delay as compared with the Release 99 DSCH.