Research And Application Of HSDPA In WCDMA System

WCDMA is one of advanced standards of 3G. It can support all kinds of services in 5MHz bandwidth and achieve 384kbit/s for downlimk packet data service in 3GPP specification Release 99. This is acceptable for most packet services at present, but it will be not enough for some data services such as video, streaming and download big files which are in strictly demands of higher throughput and shorter time delay. High speed downlink packet access (HSDPA) has been introduced into 3GPP specification in Release 5 to meet the requirement for higher speed data transmission.HSDPA includes a number of performance enhancing features such as Adaptive Modulation and Coding (AMC), Hybrid ARQ (HARQ), Fast Scheduling algorithm and etc. Based on these new features, HSDPA not only achieved a peak data rate of 14.4Mbit/s in the downlink but also could be implemented in the same carrier frequency as DCH in 3GPP Release 99. The thoughput is increased and the efficiency of frequency bandwidth is improved.HSDPA is compatible with the function entities and logical layers which are defined in Release 99. A new HS-DSCH channel is added in the physical layer of Uu interface as an evolution of DSCH and a new entity named MAC-hs is also introduced in Node B to enhance the function of the relative operation signaling in application layer.The introduction of HSDPA enabled Release 5 support higher rate serveices without changing the whole WCDMA network structure. The performance of downlink data services such as best effort is enhanced.The paper firstly studied the architecture of WCDMA system and the protocol stacks of Iu, Iur and Iub interface. The impact of these interfaces are also analysed through an actual signaling flow of PS domain services. To analyse the influence of the whole network performance after HSDPA is introduced, a series of test cases are carried out. These test cases focused on...