The Research On Peak-to-Average Power Ratio Reduction For OFDM Systems

As the rapid development in wireless communication, higher and higher data transmission was required in many services. The conventional communication system with single carrier is hard to meet the desired performance of the system. Because of its good performance on anti multi-path interference and optimum spectrum efficiency, Orthogonal Frequency Division Multiplexing (OFDM) is regarded as the key technology of the physical layer in the next generation mobile communication system. However, a major drawback of OFDM technology is its high Peak-to-Average Power Ratio (PAPR), which makes the inter-modulation distortion and severely deteriorates the performance of systems. As so, how to effectively reduce the higher PAPR of the OFDM signals is rather an important issue. In the thesis the research is mainly around this problem.In the dissertation, firstly, the OFDM system including some fundamental theories and its key technologies is introduced. Then, the definition and distribution of PAPR is presented in detail. The paper summarizes the most popular three kinds of PAPR reducing techniques, including clipping technique, coding technique and probability technique. Next, PAPR reduction including Selective Mapping(SLM) and Partial Transmit Sequences(PTS) are reviewed in detail and one PAPR reduction method which combines the Probability and Clipping method is proposed. The simulation shows this method can reduce the PAPR effectively. At last, a deep discussion is presented around how to reduce the calculation complexity with PTS approach, and an improved scheme of the suboptimal iterative algorithm is proposed in the paper. The simulation shows this algorithm can get good PAPR reduction performances with not large calculation complexity.