Study On Performance Of HSDPA Technology Based On TD-SCDMA

With the rapid development of communication technology and more requirement of high data rate, increasing the peak data rate of communication system is urgently expected in wireless communication. Besides the traditional speech service, the future mobile communication system can also provide the users with multimedia service. The peak data rate of 384Kbit/s is acceptable for most packet services in current 3G system. However, it will be not enough for high speed multimedia wireless communication in which video, voice, pictures should be provided at the same time. Those services strictly need higher throughput and shorter delay. Therefore the High Speed Downlink Packet Access, as an important enhanced wireless communication technology, is introduced into 3GPP specification.HSDPA is the new technology beyond 3G and based on the core net of GSM. It supports higher rate services without changing the whole network structure. At present, most research are based on WCDMA, the thesis deals with the HSDPA technologies in TD-SCDMA system. Compared with WCDMA, TD-SCDMA possesses a specific merit which can utilize separated carriers in the limitation of carrier source.All the research work here is based on the specifications related with HSDPA released by 3GPP. The enhancement technologies brought by HSDPA, such as the new shared channels, Adaptive Modulation and Coding (AMC), Hybrid Automatic Repeat Request (HARQ) are carried out by DSP programming in this thesis. To enhance the performance of HSDPA in TD-SCDMA, two modified techniques are proposed. One is CQI modified algorithm which resolves the problem of time delay. Another is power control of HSDPA which decreases BLER of the whole system. Both algorithms are carried out and the results show that they are feasible. Compared with old algorithms, the new schemes obviously bring better performance.