降低OFDM系统PAPR的低复杂度ACE-C算法

A low-complexity ACE-C algorithm for PAPR reduction in OFDM system

针对现有凸集映射星座扩展算法(ACE-POCS)在OFDM信号峰均功率比(PAPR)抑制过程中存在收敛速度慢、复杂度高等问题,提出一种基于ACE-POCS算法与限幅算法(Clipping)的ACE-C算法。新算法通过对输入数据序列进行分组处理,使得在运算过程中只进行低点数的IFFT和FFT变换,有效降低了运算复杂度。在4QAM调制的OFDM系统模型中对新算法的PAPR、复杂度及误码率(BER)性能进行研究分析,结果表明,与ACE-POCS算法相比,ACE-C算法的复杂度减小了1/2以上,收敛速度也得到了一定的提高,且不需要传送边带信息,实现了在PAPR抑制效率、复杂度、误码率三方面性能的折中。

Since the available active constellation extension of projection onto convex sets(ACE-POCS) algorithm has low convergence speed and high complexity in the process of peak-to-average power ratio(PAPR)suppression of orthogonal frequency division multiplexing(OFDM) signal,a new ACE-C algorithm based on ACE-POCS algorithm and clipping algorithm is proposed.The input data sequence is divided into two groups by means of the new algorithm to perform the less-point IFFT and FFT only in calculation process,which can reduce the algorithm complexity.The PAPR,complexity,bit error rate(BER) and performance of the new algorithm are studied and analyzed in OFDM system model modulated with 4QAM.The results show that,in comparison with ACE-POCS algorithm,the complexity of ACE-C algorithm is reduced by more than a half,the convergence speed is improved greatly,and the ACE-C algorithm needn′ t transmit the sideband information.Besides,the new algorithm has a compromise-balanced capability in the aspects of PAPR suppression efficiency,complexity and BER.