一种降低OFDM信号PAPR的新方法

A New PAPR Reduction Method of OFDM Signals

正交频分复用(OFDM)技术的一个缺点是信号的高峰值平均功率比(PAPR)大大降低了系统中线性功放的效率。本文提出一种新的基于Nyquist脉冲成形的PAPR抑制方法。这种方法基于选择适当的Nyquist脉冲波形集合对OFDM的各个子载波进行脉冲成形。分析论证了该方法的PAPR上限值和所用的脉冲成形波形集合。仿真结果表明该方法能有效降低任意子载波数目的OFDM信号的PAPR值,而且与已有方法相比应用更为简单。因此脉冲成形技术不仅能对传输信号进行频谱成形来提高系统的频带利用率,而且还可以减小信号的PAPR值。

One of drawbacks of orthogonal frequency division multiplexing （OFDM） technique is the high peak-to-average power ratio（PAPR） of signals ,which substantially degrades the efficiency of a linear power amplifier. A novel technique based on Nyquist pulse shaping is proposed for PAPR reduction. The method is based on a proper selection of the Nyquist pulses for shaping the different subcarriers of the OFDM modulation scheme. The maximum PAPR and the used pulse shaping waveform is derived and proved. It is shown by computer simulation that the proposed technique can achieve significant improvement in PAPR reduction of OFDM signals for any number of carriers and its implementation complexity is much low in comparison to the previous published methods. Thus pulse shaping technique can be used not only shape the spectrum of the transmitted signal to increase the bandwidth efficiency but also to reduce its PAPR.