降低OFDM信号峰均功率比的非线性压缩扩张技术

Nonlinear Companding Transform for Reducing Peak-to-Average Power Ratio in OFDM Systems

提出了一种新的用于减小OFDM信号峰均功率比(Peak-to-AveragePowerRatio,PAPR)的非线性压缩扩张技术.该技术不仅减小大幅值信号的幅值,同时也增大小幅值信号的幅值,从而增强小幅值信号抗噪声的能力.通过与传统压缩扩张技术的对比,详细介绍了新压缩扩张技术的方法、计算复杂度以及分析了对PAPR的改善幅度及其用于OFDM系统时对系统误比特率的改善等方面的性能.实验仿真结果说明,新的非线性压缩扩张技术可以获得更为高效的系统性能增益.

A new companding transform scheme is proposed to reduce the Peak-to-Average Ratio (PAPR) of Orthogonal Frequency Division Multiplexing (OFDM) signals. By exploiting statistical distribution of transmitted OFDM signals, the proposed scheme effectively reduces the PAPR by compressing the peak signals and expanding the small signals, while maintaining the average power unchanged by properly choosing transform parameters. The characteristics and performance of system with conventional and new companding scheme are compared. The proposed scheme is illustrated in detail and analyzed in terms of reducing PAPR, computational complexity and improvement in BER performance in OFDM system. The simulation results confirm that the suggested scheme exhibits a good ability to reduce PAPR and a good BER performance with a Solid State Power Amplifier (SSPA) and in an Additive White Gaussian Noise (AWGN) channel.