Researches On Frequency Domain Equalization In TD-SCDMA System

With the developments in communications industry, various new technologies and standards appear continuously. Proposed by our country, TD-SCDMA is one of the three standards of third generation (3G) mobile communication systems. Since proposed and recognized by the International Telecommunication Union, TD-SCDMA standard keeps on improving and developing. Especially with the increase of people's demands on high data rate services, TD-SCDMA introduces HSDPA (High-Speed Downlink Packet Access) into the Release 5 (R5) version. After several years of development, HSDPA standard has become one of the most competitive technologies in 3.5G standards.Based on the introduction and analysis of the physical-layer key technologies of TD-SCDMA, the thesis builds the link-level simulation platform under the HSDPA standard framework of TD-SCDMA system.Secondly, the signal detection technologies at the receiver side of HSDPA are investigated. The performance of signal detection technologies decides the capability of system against poor channel condition involving multipath, multiple-access and noise, which determines the link error rate directly. The joint detection algorithm used in HSDPA and the channel estimation technology affecting the performance of joint detection are investigated and simulated. The simulation results show that the algorithm exhibits good performance.The main purpose of the thesis is to investigate the frequency domain equalization (FDE) signal detection algorithm and apply it to HSDPA to improve the receiving performance. The thesis focuses on the comparison researches on FDE with guard interval (GI), Overlap FDE and iterative FDE with interference cancellation(IC). The algorithm is simulated under the framework of HSDPA, the results of which show that the algorithm outperforms the joint detection algorithm in the context of several typical conditions. In addition, the complexity of the algorithm is analyzed, which shows that the algorithm possesses low complexity and is feasible for implementing at receiver.The final part concludes the work in the thesis and point out the future direction of the related technologies.