一种新的OFDM峰均功率比抑制算法

New OFDM peak-to-average power reduction scheme

峰均功率比(PAPR)过高是OFDM系统的一个主要缺点,由于OFDM发射端功率放大器的非线性,高的峰均功率比会导致信号的频谱扩展,同时降低了放大器的工作效率。传统的削波算法虽然能够简单有效地降低信号的峰均功率比,但是会带来较大的额外频谱增益。为了克服传统削波算法的缺点,文中提出一种新的削波算法,该算法在降低PAPR的同时做到零频谱增益。并基于传统削波产生误差信号,通过对误差信号的滤波,以牺牲信号的EVM实现了零频谱增益。但又会带来较大的带内干扰,仿真表明配合相应的噪声消除算法,其误码性能接近未削波的原始信号水平。

A main drawback of frequency division multiplexing （OFDM） system is the high peak-to-average power ratio （PAPR）. High PAPR leads to amplifier nonlinearity, inter-modulation and low inefficiency. As a simplest approach, traditional clipping method can reduce PAPR of OFDM signals, but it causes large unwanted out-of-band radiation. In this paper, a new clipping method is proposed, which can reduce PAPR without out-of-band radiation. It is based on the traditional clipping to generate the error signal. Zero outof-band radiation is achieved by filtering the error signal. Although the proposed method produces more inband noise, by using noise cancel algorithm, the ideal unclipped signal＇s BER performance can be achieved.