Research On PAPR Reduction Technology In OFDM High Speed Data Transmission System

In recent years,the wireless high-speed-data transmission system is of great significance in both military-use and civil-use field.OFDM is increasingly being the main technology of wireless high-speed data transmission system for its high spectral utilization,high performance of resistance to multipath fading channel,strong ability of frequency selective fading resistant performance,and so on.However,there are many difficulties and problems.For example,OFDM is sensitive to frequency deviation and phase noise,and the Peak Average Power Ratio(PAPR)is relatively larger.The PAPR reduction,as the key technical problem in OFDM systems,is crucial to the promotion of the adoption of OFDM in various fields and applications.While in high speed wireless transmission systems,due to the stringent demands on the power efficiency,the PAPR reduction is particularly important in the implementations of the whole system.This paper takes the development of the OFDM high-speed data transmission system in the satellite-to-ground link as the researching background.The solution of the OFDM high-speed data transmission system of satellite and ground transmission environment was studied,which focuses on the problem of PAPR reduction in the system was studied.A comprehensive research from the generation mechanism of PAPR to the statistical properties and measurements of PAPR was conducted,and the relevant parameters which influence the PAPR performance was analyzed,various solutions to this kind of problem were also studied.Finally an improved algorithm of the PAPR reduction of the satellite OFDM high-speed data transmission system was proposed,and FGPA implementation of the proposed algorithm was conducted.Several PAPR suppression methods,the Clipping method,the Pressure expansion transformation method,the Selective Map(SLM)and the Partial Transmit Sequence(PTS)method,were intensively studied.Theoretical analysis and simulations prove that the PTS algorithm outperformed others compared in PAPR suppression performance,implementation complexity and high speed realization.Thus the PTS algorithm is chosen for the OFDM high-speed data transmission system.The traditional PTS algorithm is of relatively high computational complexity.In order to facilitate its application in this system,the improvements and optimization of the PTS algorithm was being deeply researched,and the iterative algorithm of interweaving segmentation and the optimized PTS algorithm combined with interleaving method were proposed.This two modified algorithms are analyzed and compared with traditional PTS method.The first improved algorithm greatly reduces the required hardware resources and the amount of calculation of the OFDM high-speed data transmission system,while the second optimization algorithm has a great effect on the performance of PAPR suppression,and the computational complexity of the system has a certain degree of improvement.Aiming at the high speed realization of the PAPR algorithm,the paper puts forward the hardware implementation scheme of the iterative PTS algorithm of interweaving segmentation.The algorithm greatly reduces the complexity of the algorithm of hard ware implementation,and can reduce PAPR of the system 2.4dB(CCDF=0.1%).Finally,based on the satellite high-speed data transmission system hardware platform,hardware implementations of the algorithm was designed,which proves that the algorithm can meet the requirements of processing speed and the implementation complexity of high-speed data transmission system.