Research Of PTS For Papr Reduction Of OFDM Signals

Due to its extensible network, its good filter performance and robustness to multipath interference, its high transmission speed and its high spectrum efficiency, Orthogonal Frequency Division Multiplexing (OFDM) is considered as a key role in the fourth generation wireless mobile communication systems (4G). And OFDM has found its wide applications in asymmetric digital subscriber loop (ADSL), wireless local loop (WLL), digital audio and video broadcasting (DAB, DVB), wireless local area network (WLAN), Long Term Evolution (TD-LTE) and the global microwave Internet Access (WiMax). But one defect of OFDM system is high Peak to Average Power Ratio (PAPR). After researching reducing PAPR of OFDM signal with Partial Transmit Sequence(PTS) technique, two directions'improvements of PTS have being proposed: 1) in other performances basically unchanged condition, improving the ability of inhibiting OFDM signal's PAPR; 2) under the same performance of inhibiting PAPR, reducing the algorithm complexity of PTS.In the first part of this dissertation, the basic principle and key technologies of OFDM system are introduced, then PAPR's statistic characteristic and its impact on OFDM system are studied, and the existing techniques of inhibiting OFDM signal's PAPR, especially PTS, PS and SLM, are analyzed.In the analysis of the principle advantages and disadvantages of PTS and PS, PS-PTS Joint-technique is proposed, and then is improved properties of raising the bandwidth efficiency and reducing the algorithm complexity. The simulation results show that, compared to PTS having basically the same bandwidth efficiency, PS-PTS Joint-technique improves the performance on inhibiting PAPR of OFDM system and reduces the algorithm complexity; compared to PS having the same bandwidth efficiency, PS-PTS Joint-technique enhances the capability of Inhibition of inhibiting PAPR of OFDM signals. Finally, the principle of PAPR's inhibition of PTS technique based on improved discrete binary particle swarm optimization (DPSO) is studied in this dissertation. The simulation results show that, compared with DPSO, PTS based on the improved DPSO has a high-performance on inhibiting PAPR of OFDM signals with the same searching times.