为降低可见光通信系统的误码率, 提高系统的传输特性, 研究了可见光通信系统的信道均衡技术。建立了室内可见光通信系统的信道模型, 阐述了信道的直射冲激响应和反射冲激响应。针对多径效应导致的码间串扰问题, 采用一种改进的LMS(最小均方)算法对信道进行补偿。实验结果显示: 采用改进的LMS算法后, 收敛速度更快, 在系统趋于稳定时, 误码率明显降低。均衡器对时变信道跟踪效果更好, 系统稳态误差相对减小。

In order to reduce the bit error rate and improve the transmission performance of the Visible Light Communication (VLC) system, the channel equalization technology is studied in this paper. The channel model of the indoor VLC system is established. The direct impulse response and reflected impulse response of the channel are also analyzed. A new variable-step-size Least Mean Square (LMS) algorithm is used to compensate the Inter-Symbol Interference (ISI) induced by multi-path effects. The experimental results show that the proposed LMS algorithm has faster convergence rate, which can achieve lower bit error rate when the system is stabilized. The adaptive equalizer has a better tracking performance on time-varying channel and system steady-state error is also reduced.