面向5G三大应用场景的F-OFDM系统PAPR抑制算法研究

曾作为5G候选波形技术的基于子带滤波的正交频分复用(Filtered-Orthogonal Frequency Division Multiplexing,F-OFDM)是基于正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)发展而来的,和OFDM一样存在峰值平均功率比(Peak to Average Power Ratio,PAPR)的问题。高PAPR的信号在发送时对系统功率放大器的性能要求很高,容易发生信号失真,并且会直接影响整个系统的运行成本和效率。为了提高F-OFDM系统在5G三大应用场景中的PAPR抑制性能,引入一种基于迭代限幅滤波的次优PTS抑制算法。该算法主要分为两个过程,先对F-OFDM系统的各子带的高PAPR值信号进行线性抑制,然后待各子带的信号经过各自的数字子带滤波器合并后再进行迭代限幅滤波处理,从而完成对F-OFDM信号PAPR的抑制。仿真表明,该算法相对于单独使用次优PTS算法或迭代限幅滤波算法,能提高F-OFDM系统的PAPR抑制性能。

PAPR Suppression Algorithm for F-OFDM System Facing Three Major Application Scenarios of 5G

F-OFDM(Filtered OFDM),once as a candidate for 5G waveform technology,is developed from OFDM(Orthogonal Frequency Division Multiplexing)and has the same problem of PAPR(Peak to Average Power Ratio)as OFDM.High PAPR signals have high requirements for the performance of the system power amplifier when transmitted,prone to signal distortion,and this will directly affect the operating cost and efficiency of the entire system.In order to improve the PAPR suppression performance of the F-OFDM system in the three major application scenarios of 5G,a sub-optimal PTS suppression algorithm based on iterative clipping filtering is introduced.The algorithm is mainly divided into two processes,that is,firstly the high PAPR signals of each sub-band of the F-OFDM systems are linearly suppressed,and then the signals of each sub-band merged by their respective digital sub-band filters,thereby the iterative clipping filtering process is performed to complete the PAPR suppression of the F-OFDM signal.Simulation results indicate that this algorithm can improve the PAPR suppression performance of F-OFDM system compared to suboptimal PTS algorithm or iterative clipping filtering algorithm alone.