Research On PAPR Performance Optimization Algorithm Of GFDM System

Generalized Frequency Division Multiplexing(GFDM),GFDM is based on data block modulation of a non-orthogonal multi-carrier technology,which is different from Orthogonal Frequency Division Multiplexing(OFDM).The difference of OFDM technology is that it has the characteristics of small out-of-band radiation range,high spectral efficiency,strong multi-frequency focusing and high multi-service reliability.The application of GFDM multi-carrier technology to satellite mobile communication network can greatly improve the signal quality,promote the combination of satellite communication network and earth cellular mobile communication network,and achieve the integration of heaven and earth communication system.However,the Peak-to-Average Power Ratio(PAPR)of GFDM multi-carrier system is overtop the peak power of the system.The Bit Error Rate(BER)performance of the system and the efficiency of High-Power linear Amplifier(HPA)are greatly affected.In order to meet the demand for multi-carrier technology in current and future practical applications,this paper improves the existing PAPR suppression technology in the current multi-carrier system,and proposes the following algorithm to solve the problem of high PAPR in the system.In GFDM system,for the sake of settling a matter of high PAPR,in this paper proposes Cos nonlinear distributed compression expansion suppression algorithm and DHT precoding combined compression expansion suppression algorithm.The Cos nonlinear distributed compression and expansion algorithm is different from the existing compression and expansion algorithm.By defining the specific probability distribution of the new signal amplitude distribution after compression and expansion,the corresponding compression and expansion function is derived in reverse.It only transforms the amplitude of the signal and keeps the phase constant,so that the small amplitude signal can be properly amplified and the large signal can be compressed,which can effectively reduce the PAPR of GFDM system and ensure the BER performance of the system as much as possible.DHT precoding algorithm in frequency domain and Cos function compression and expansion algorithm in time domain can achieve better PAPR suppression effect.In order to reduce the PAPR performance of GFDM system,a PAPR suppression algorithm based on the allocation of different filters of parity and parity carriers is proposed,which has low computational complexity.Since the GFDM system can flexibly select filters,this method assigns RC filters to odd carriers and RRC filters to even carriers after determining odd carriers and even carriers.This method can adjust the consistency of each subcarrier phase when transmitting signals in the GFDM system,thus reducing the PAPR of the system.The Matlab simulation experiment shows that the proposed algorithm does not add unnecessary calculation in the calculation aspect,the complexity is low,and has good practicability.