Research And Implementation Of Peak-to-average Power Ratio Reduction Technique For OFDM Systems Using USRP

Software radio uses software programming to realize the rapid construction and deployment of communication systems,subverting the dependence of communication modes on hardware in traditional wireless communication,which can greatly reduce the development cost of communication systems and accelerate the update of wireless communication technologies.The software radio platform combining GNU Radio and USRP is one of the widely used platforms in the field of wireless communication.Orthogonal Frequency Division Multiplexing(OFDM)technology is widely used in various wireless communication systems such as 4G-LTE and WiFi due to its advantages in spectrum efficiency,multipath fading,and low implementation complexity.However,OFDM technology also has many shortcomings.The peak-to-average power ratio will reduce the linear range of the power amplifier,affecting the efficiency and performance of the entire communication system.This paper focuses on the peak-to-average power ratio reduction technology of OFDM system and the implementation of USRP.The main research work includes:1.Aiming at the problem that the traditional PTS algorithm reduces PAPR performance,a suboptimal PTS-Clipping joint algorithm is proposed.The algorithm reduces the computational complexity of the phase factor search process by setting a reasonable threshold,and combines signal clipping to reduce the noise interference caused by the threshold being too low.The simulation results show that the algorithm can reduce PAPR more effectively and its computational complexity is also improved.2.Aiming at the problem of multi-subblock number of traditional PTS algorithm,an improved PTS algorithm based on hybrid modulation map-ping is proposed.The algorithm introduces BPSK/QPSK/8PSK/ 16 PSK multiple hybrid modulation methods in the data source code mapping process,and reduces the number of OFDM subcarriers to 1/3-1/2.The simulation results show that the algorithm can effectively reduce the PAPR effect of the system.3.The software radio platform based on GNU Radio and USRP X310 is built to realize the transmission and reception of OFDM signals.The system test of the joint algorithm of reducing the peak-to-average power ratio PTS is completed,and the effectiveness of the algorithm and the system transmission performance are verified.