Td-scdma Uplink Synchronization Algorithm And Dsp Implementation

To the emergence of cellular systems as a starting point, with development of integrated circuit technology, computer and Communication technology,mobile communication have developed in time of 3G. The 3G mobile communication system is forward to globalization,integration and personalization, WCDMA, CDMA2000 and TD-SCDMA as the main representatives of 3G.TD-SCDMA is a Chinese 3G mobile communication wireless interface standard, which is submitted to ITU, accepted as a part of CDMA-TDD in international norms. This is a major breakthrough in the history of Chinese telecommunications, and important milestone in the development for mobile communications in China. Differ from WCDMA and CDMA2000 which implement with FDD, TD-SCDMA combines advantages of CDMA and TDD, With a flexible air interface, use smart antennas, joint detection and other advanced technologies, have a very high technical features. It has the highest spectral efficiency in the three mainstream standard.The key technologies of TD-SCDMA mainly are concentrated in the baseband part, such as smart antenna, joint detection, uplink synchronization, dynamic channel allocation, relay switching, the wireless network, power control, software radio, channel estimation and so on. TD-SCDMA is a synchronous CDMA, synchronization technology is an important technology to reduce multiple access interference, enhance system capacity and simplify the receiver. In the CDMA system, the downlink is always synchronized, so in general said, synchronous CDMA means uplink synchronization, which requires uplink signals from different distances and different user terminals to arrive at base station the same time.Uplink synchronization algorithm in TD-SCDMA is based on the good auto-correlation of the sequence which is used for synchronization, and has greatly computation. In this article, according to sub-frame structure of TD-SCDMA, we adopt an algorithm based on detect-window, which greatly reduces the computation of synchro sequence search algorithm. Furthermore, some improvement methods based on TD-SCDMA features and correlation has been proposed in order to improve the performance of the algorithm. The results from MATLAB simulation show that the improved algorithm is valid. In order to implement the algorithm on DSP effectively, fix-point simulation for this algorithm has been done in this article. Although floating-point calculation has better accuracy, fixed-point calculation requires cheaper platform and costs less.This article is based on DSP implementation TD-SCDMA uplink synchronization algorithm.Based on the structural characteristics of MSC8144 multi-core DSP, optimized and improved the algorithm.To improve efficiency of program,have improved the implementation approach on data storage, complex multiplication,and so on.By researched on task distribution, data communication and interactive about multi-core DSP,improve utilization and efficiency of DSP.The result,form the improved uplink synchronization algorithm run on MSC8144,show that the time, which spend on completing uplink synchronization, satisfy the demand of system.