Research On PAPR Reduction Technology In OFDM System

Orthogonal Frequency Division Multiplexing(OFDM) is a parallel transmission scheme of MCM(Multi-Carriers Modulation).It transmits information through orthogonal sub-carriers and has very high utilization of frequency spectrum and good capability of countering multi-path interference.This technology is very fit to the transmission of high-rate and multimedia service.However,the high peak-to-average power ratio is always one of the main drawbacks of OFDM.This paper mainly focuses on the analysis to the PAPR reduction algorithms,and then proposes two design schemes based on the algorithms analyzed above.The paper firstly analyzes the conventional clipping algorithm,followed by two kinds of improved algorithms named CF and RCF respectively for the reason of the re-growth of the peak value after the D/A convention in the conventional clipping algorithm.Because of the serious deterioration of the bit error ratio induced by the clipping noise introduced by the non-linearly operation of the algorithm,this paper analyzes two clipping-noise estimation algorithms,which will improve the performance significantly when combined with the clipping algorithms according to the computer simulation result.Secondly,this paper analyzes a reduction method called Active Constellation Extension(ACE),followed by the analysis to a improved method of ACE named ACE_BD.According to the simulation result,the method is proven to be a very good reduction scheme when it applies the algorithms of POCS and SGP.At last,theμcompanding reduction papr algorithm is introduced,and computer simulation result is presented.The paper also introduces the performance of the SLM and PTS of PAPR reduction and compares the PAPR algorithms.After the analysis of the algorithms mentioned above,this paper proposed two schemes of the transceiver with the function of the control to PAPR.The first scheme, which makes the complexity mainly standing at the base-station and makes the mobile devices esay,it is suitable for the mobile communication systems.This scheme decrease the complexity and cost of the whole system,The second proposed scheme is based on the RCF algorithm,it is very easy to be implemented in the FPGA.