Research On Papr Reduction Techniques In OFDM System

Orthogonal Frequency Division Multiplexing (OFDM) is a parallel transmission scheme of Multi-carriers Modulation (MCM) with very high utilization of spectrum and good capability of countering multi-path interference. However, the high Peak-to-Average Power Ratio (PAPR) is always one of the main bottlenecks of OFDM development. This paper mainly focuses on the analysis to the effective PAPR reduction algorithms and the main contents are as follows:At the first of the thesis, we elaborate the principle of OFDM system, its key techniques, advantages and disadvantages of OFDM, the issue and cause of high PAPR in OFDM is also given.After that, the PAPR reduction techniques for OFDM system are studied, and various algorithms, such as clipping, Selective Mapping (SLM), Partial Transmit Sequences (PTS) and Active Constellation Extension (ACE) are introduced. Then simulation is performed to analyze the performance of these algorithms.Then, the clipping and ACE methods are discussed in detail, and the PAPR reduction performance of ACE algorithm is analyzed. A novel PAPR reduction technique combined with clipping and ACE for OFDM system is proposed.At last, the theory and realization procedure of the union algorithm based on clipping and ACE is described in detail and algorithm computation complexity is analyzed. Simulation result shows that the proposed union algorithm can reduce PAPR effectively, and there is a trade-offs among computation complexity, PAPR reduction and BER performance.