基于子空间的无线光通信副载波盲均衡算法研究

文中基于Gamma-Gamma光强起伏分布大气湍流信道模型,对无线光副载波相移键控调制系统进行了子空间盲均衡算法的研究。对比分析了经过大气湍流信道盲均衡前后的副载波调制信号星座图聚敛性,给出了均衡后不同光强起伏方差下的误码率曲线,当R2=0.1,信噪比为20 dB时,误码率从4.710-1降低到1.5610-3,均衡后误码率明显改善。同时采用两种典型实测天气数据(阴、中雨)模拟大气信道进行了子空间盲均衡实验,均衡后调制信号星座图聚敛性与相位可识别性明显优于均衡前。仿真结果表明,子空间盲均衡算法对大气湍流信道下的副载波调制信号有良好的均衡效果。

Blind equalization algorithm of wireless optical communication using subcarrier modulation based on subspace

In this paper, subspace blind equalization algorithm of wireless optical communication using subcarrier modulation was studied based on Gamma-Gamma optical intensity scintillation distribution model. The constellations of the subcarrier multiple phase shift keying modulation signal through the atmospheric turbulence channel before and after the blind equalization was compared, and the bit-error-rate(BER) curves of the system under different scintillation distributions was given. When R=0.1 and SNB=20 dB,the BER was reduced from 4.710-1 to 1.5610-3. The BER performance was obviously improved. At the same time, measured data in two kinds of weather conditions(cloudy,rainy) which were described to atmospheric channel, was used in the experiment of subspace blind equalization. Clustering performance and phase identifiability of the constellation after equalization are obviously better than before equalization. The simulation results show that the subspace blind equalization algorithm has a good effects on equalization of subcarrier modulation signal under the atmospheric turbulence channel.