Research On OFDM Peak-to-Average Power Ratio Reduction Technology

Orthogonal frequency division multiplexing technology has been widely used in 4G,5G,WIFI and DVB standards or systems,and it will also play an important role in the future air-space integration network.Although OFDM technology has superior performance in combating multipath fading and increasing data transmission rate,the problem of high peak-to-average power ratio in OFDM systems has still not been solved well,and the problem of peak-to-average power ratio is particularly prominent in satellite networks.Although there are many researches on OFDM PAPR reduction,it is still a big problem to find a method that guarantees BER performance,low complexity and good peak-to-average ratio suppression.The research on PAPR reduction technology can not only improve existing satellite transmission technologies,but also improve the performance of terrestrial cellular network greatly.Therefore,the research on PAPR reduction technology is of great significance to the development of communication technology.In this paper,two existing researches on the Selective Mapping and Clipping of the PAPR reduction technology are studied.The shortcomings of these two technologies are analyzed.We propose effective solutions for the method of non-side information transmission in Selective Mapping technology and Clipping Distortion Recovery in Clipping technology.For the research on the method of non-side information transmission in Selective Mapping technology,we propose a semi-HSLM method based on the semi-Hadamard matrix without side information.First of all,for the problem of tightly coupled phase information,we decouple the phase information to phase rotation information and side information,and design them separately.The decoupling design enables peak-to-average ratio suppression and side information hiding to be studied separately.Secondly,for the redundancy of the Hadamard matrix as the phase rotation information,we propose a semi-Hadamard matrix generation method,so that the proposed scheme can obtain the same PAPR reduction performance and use half of the phase information in Hadamard matrix.The complexity of the phase information recovery in receiver is reduced.Aiming at the problem of side information hiding,we propose an interval increasing cyclic shift matrix to hide the side information.The proposed scheme can effectively reduce the PAPR,and realize the side information hiding with little loss of bit error performance.Aiming at the research of Clipping Distortion Recovery method in Clipping technology,we propose a signal-aided Clipping Distortion Recovery method based on compressed sensing.For the problem that the OMP algorithm is difficult to obtain the sparseness information in the actual system,we propose a scheme for transmitting the sparseness information by using auxiliary signal,and the proposed auxiliary signal method can not only transmit the sparseness information of peak clipping distortion,but also transmit the non-zero position information of sparse signal.Using the non-zero position information transmitted by the auxiliary signal,we improved the OMP algorithm and proposed a location-assisted OMP algorithm.At the same time,an iterative recovery receiving scheme is also proposed,which uses the recovered Clipping Distortion information to improve the accuracy of the auxiliary signal recovering.The proposed transmission scheme effectively solves the problem that the compressed sensing algorithm cannot be used at high clipping rate.The proposed modified algorithm greatly simplifies the complexity of the OMP algorithm.Finally,the iterative recovery algorithm can be performed in fewer iterations and get excellent error performance improvement.Finally,we have summarized the whole paper,and put forward the problems of the existing schemes and the directions that can be improved in the future.