OFDM削波噪声迭代消除算法

Iterative clipping noise cancellation for OFDM signals

高峰均功率比(PAPR)的OFDM信号通过功率放大器的时候会产生非线性干扰,同时降低了放大器的工作效率。传统削波算法可以降低信号的PAPR,但是会带来较大的频谱扩展。作为一种新的削波算法,误差削波可以在降低OFDM信号PAPR值的同时不带来任何频谱扩展。但是这种削波会给信号带来更大的带内干扰噪声。提出了一种OFDM削波噪声迭代估计和消除算法,它能有效的消除由于误差削波带来的噪声。新方法通过建立削波噪声模型,在接收端根据该噪声模型用迭代的方法重新产生削波噪声。仿真结果表明,使用削波噪声消除算法后,使得系统的误码率性能接近未削波信号的水平。

Orthogonal frequency division multiplexing （OFDM） signals with high peak-to-average power ratio （PAPR） are distorted nonlinearly by the high power amplifier （HPA）. The traditional clipping method can reduce PAPR of OFDM signals, but causes large unwanted out-of-band radiation. As a new clipping technique, error clipping can reduce PAPR of OFDM signals without any out-of-band radiation. However it will cause more in-band distortion. In this paper, an iterative receiver is proposed to estimate and cancel the distortion caused by error clipping. It can effectively reduce clipping noise by reconstructing error clipping noise based on the noise model. Simulation results show that the system performance can be restored to the ideal unclipped signal level with only moderate complexity.