π/2相移非正方形M-QAM调制方式  

π/2 phase shift non-square M-QAM modulation

作　　者：刘昌清[1] 杨知行 郭兴波[1] 

机构地区：[1]清华大学电子工程系微波与数字通信技术国家重点实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2006年第10期1688-1690,1694,共4页Journal of Tsinghua University(Science and Technology)

摘　　要：为了降低非线性信道对正交幅度调制(QAM)信号的频谱和误码性能的影响,根据消除连续星座点间180°相位跳变可以降低信号功率峰均比的原理,提出了一种新的π/2相移非正方形M-QAM调制方式,以及一种简化的调制端实现方法。仿真结果表明,和常用的非正方形M-QAM调制方式相比,对于信道非线性引起的高阶频率扩散,该文提出的方法有5 dB的改善;在不同的非线性强度下,误码性能也有不同程度的改善,在平均误码率(BER)为10-3时,改善均大于1dB,而且随着信道信噪比的提高,改善更为明显。A simplified π/2 phase shift non-square M-QAM modulation method was developed to reduce the effect of nonlinear channels on the spectrum and bit error rate performance of quadrature amplitude modulation （QAM） signals. The peak-average power ratio of the signal can be reduced by removing all 180° phase transitions between continuous signal points. Simulation results show that compared with the conventional M-QAM modulation, the frequency spread caused by＇nonlinear channels is improved by 5 dB, while the bit error rate performance is improved as a function of the size of the nonlinearities in the channel. The method gives an improvement of more than 1 dB at BER = 10^-3, and the improvement will increase as the signal to noise ratio increases.

关 键 词：调制 π/2相移非正方形M-QAM 非线性信道 

分 类 号：TN911.3[电子电信—通信与信息系统]