瑞利衰落信道下QAM-OFDM可见光信号传输特性的研究

Research on transmission characteristics of QAM-OFDM visible signals in rayleigh fading channel

为了分析在单径和多径瑞利信道下可见光信号的收发特性,研究了基于白光LED作为光源、采用瑞利衰落信道传输以及应用三种不同QAM-OFDM信号的室内可见光通信系统。首先,采用MATLAB软件搭建了支持三类QAM-OFDM信号实现可见光通信系统仿真的模型;然后,分析了三类QAM-OFDM信号在单径和二径瑞利衰落信道下的误码率(BER)与接收信号信噪比(SNR)的关系;最后,综合频带利用率和数字信号处理过程考虑,建议实际应用中选用8QAM-OFDM信号进行收发。此外,还基于照度分析结果验证了8QAMOFDM信号的实际应用可行性。

In order to analyze the transmission and reception characteristics of visible light signals in single-path and multi-path Rayleigh channels,we design an indoor visible light communication system based on white LED,in which three kinds of QAM-OFDM signals are used under Rayleigh channel condition.Firstly,the simulation model of visible light communication system supporting three types of QAM-OFDM signals is built by using MATLAB software.And then,the relationship between the bit error rate(BER) and the received signal-to-noise ratio(SNR) of three types of QAM-OFDM signals in single-path and two-path Rayleigh fading channels are analyzed.It is suggested that 8 QAM-OFDM signals should be selected in the transceiver in practical application,if the bandwidth utilization and digital signal processing are considered.At last,the feasibility of 8 QAM-OFDM signal is verified by illumination analysis.