Effects of UE capabilities on high speed downlink packet access in WCDMA systems

High speed downlink packet access (HSDPA) is specified in the 3GPP to cope with the increasing demand of high-speed Internet-based multimedia services. HSDPA is based on techniques such as base station scheduling, adaptive modulation and coding, hybrid automatic repeat request, and advanced receiver design. This work presents system-level simulation results on the HSDPA performance to reveal the effects of user equipment (UE) capabilities such as the maximum number of multicodes and receive diversity. The results show that a 15- and 10-multi-code UE and the receive diversity significantly improve the cell capacity. Experiments using the HSDPA test-beds are conducted to investigate the true HSDPA performance. Furthermore, TCP/IP-level simulation results show the application-level throughput, i.e. end-user throughput, in the HSDPA system. The results indicate that reduction of the round trip time, a higher uplink data rate, and low uplink block error rate are required to achieve the high TCP-level throughput.