Research On Reducing PAR In TD-SCDMA System

With the sharply increasing data transmission business in modern communications, a new communication system supporting multimedia services, data transmission of higher rate, more efficient spectrum utilization and mass capacity is required. The TD-SCDMA, as one of 3G standards, meets to the requirements of techniques and market. Furthermore, as the independent intellectual property communication standard of China, the Chinese government and many domestic enterprises have been paied much attention to the TD-SCDMA and it becomes the hot field in recent years.Although TD-SCDMA has a good performance, the way of its modulation and some other reasons cause high Peak-to-Average Ratio (PAR). The problem reduces the efficiency of power amplifier and leads to signal distortion hence reduce all the performance of the system. Based on the principles of TD-SCDMA system, this paper explains the determinants of PAR in the TD-SCDMA system. Then, several methods are discribed to reduce it and a best method is adopted by considering the characteristics of TD-SCDMA system. The paper mainly focuses on the kind of amplitude limit. Firstly, the basic methods of limiting algorithm are introduced. Then, the way of Peak Windowing and Pulse counteract to reduce the PAR across intermediate frequency is explained. At last, a MATLAB simulation programe is developed to analyze the principle and performance of these methods in details.