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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σ2R=0.1,信噪比为20 d B时,误码率从4.7×10-1降低到1.56×10-3,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。
In this paper, based on Gamma-Gamma fluctuating atmospheric turbulence channel model, the sub-spatial blind equalization algorithm for wireless optical subcarrier phase shift keying modulation system is studied. The constellation convergence of subcarrier modulated signals before and after blind equalization of atmospheric turbulence channel is analyzed and compared. The error rate curve of the modulated signals with different light intensity fluctuations is obtained. When σ2R = 0.1 and signal to noise ratio is 20 dB , Bit error rate decreased from 4.7 × 10-1 to 1.56 × 10-3, the bit error rate improved significantly after equalization. At the same time, two typical measured weather data (overcast and mid-rain) were used to simulate the atmospheric channel, and the subspace blind equalization experiment was performed. The convergence and phase identifiability of the modulated signal constellation after the equalization is obviously better than that before the equalization. The simulation results show that the sub-space blind equalization algorithm has a good balance effect on subcarrier modulated signals under atmospheric turbulence channel.