An Analysis And Improvement On Algorithms Of Reducing High PAPR In OFDM System

Orthogonal Frequency Division Multiplexing (OFDM) is getting more and more attention for its advantage over against multi-path time delay extension in wireless channel. But it also has some disadvantages and problems. A great obstacle of applying OFDM is the high Peak-to-Average Power Ratio (PAPR). This article is mainly concerned with the high PAPR problem in OFDM and compares reduction methods of PAPR. First give out a summary about history of Telecommunication system development. Then discuss theory of OFDM, provide OFDM system model realization and bring the issue of high PAPR in OFDM.From the third chapter, the article focuses on theory and cause of high PAPR in OFDM and gives out the theory of high PAPR. Then begins to discuss various methods using to reduce PAPR currently, which divide into three categories—distortion method to reduce PAPR by signal distortion, coding method, and non-distortion method. The realization of distortion method is simple but will cause serious signal distortion and bring down the BER performance. The coding method can bring good PAPR performance on the cost of increasing system bandwidth and transmitting bit power. The non-distortion can reduce PAPR efficiently but is complicated in realization. Based on those analyses, the article gives out an improved method which combines Gold code with SLM. The theory will be introduced and performance will also be presented. Moreover, gives out an improved algorithm of traditional PTS. Last charpter is a summary of this article.