一种改进的降低OFDM信号PAPR的虚拟序列插入方法

An Improved DSI Method for PAPR Reduction of OFDM Signal

OFDM（正交频分复用）系统在时域上的高PAPR（峰值平均功率比），会导致OFDM信号在传输过程中引入互调噪声，严重降低系统的BER性能。文章研究了一种改进的虚序列插入（DSI）方法，可以得到更好的PAPR性能。该方法的特点在于使用时频域交换算法来改变所有时域信号的预定相位系数，从而优化每一个虚拟子载波的相位，并降低系统的PAPR。文章给出的计算机仿真结果表明，与传统的DSI方法相比，该方法可以在降低系统复杂度的同时得到更好的PAPR性能。

The high PAPR（Peak to Average Power Ratio） of OFDM signal in time-domain will cause intermodulation noise during transmission, which will degrade the BER （bit error rate） performance of the system heavily. In this paper, an improved DSI （Dummy Sequence Insertion） method is analyzed. This method can achieve a better PAPR performance. The time-frequency domain swapping algorithm is adopted to change the predetermined phase coefficients of all time-domain signals. Thus the phase of each dummy subcarrier is optimized, and the PAPR performance of the system is degraded. Simulation results show this method can get better PAPR performance while the complexity of the system is less, comparing with traditional methods.