MIMO-OFDM可见光通信系统的自适应信道估计  

Adaptive Channel Estimation for MIMO-OFDM Visible Light Communication System

作　　者：陈勇[1] 尹辉[1] 刘焕淋[2] 

机构地区：[1]重庆邮电大学工业物联网与网络化控制教育部重点实验室,重庆400065 [2]重庆邮电大学光纤通信技术重点实验室,重庆400065

出　　处：《中国激光》2016年第9期217-223,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(61071117);重庆市研究生科研创新项目(CYS15172);重庆市基础与前沿研究计划(cstc2015jcyjA40024)

摘　　要：针对LED通信系统中信道估计性能低的问题,提出了将正交频分复用(OFDM)系统与多输入多输出(MIMO)技术相结合的可见光通信系统及其基于信噪比的自适应信道估计算法。通过对最小二乘法(LS)、最小均方误差(MMSE)、离散傅里叶变换改进最小二乘法(LS-DFT)、离散傅里叶变换改进最小均方误差(MMSE-DFT)以及分布式压缩感知同步正交匹配追踪(DCS-SOMP)5种信道估计方法的研究,确定了信噪比的临界阈值。当信噪比低于临界阈值时,采用MMSE-DFT算法进行信道估计;当信噪比高于临界阈值时,选用DCS-SOMP算法进行数据重构并恢复信道脉冲响应矩阵。仿真结果表明,当信噪比为1dB^40dB时,所提算法的均方误差得到有效降低(2.95dB^15dB),且LED通信系统的通信质量得到提高。To solve the low channel estimation performance of LED communication system, a visible lightcommunication system which combines the orthogonal frequency division multiplexing （OFDM） system with themultiple input multiple output （MIMO） technology and its adaptive channel estimation based on signal-to-noise ratio（SNR） are proposed. The critical threshold of SNR is determined when the five algorithms, i.e., least squares（LS）, minimum mean square error （MMSE）, least squares-discrete Fourier transform （LS-DFT）, minimum meansquare error-discrete Fourier transform （MMSE-DFT） and distributed compressed sensing synchronous orthogonalmatching pursuit （DCS-SOMP）, are analyzed. When SNR is lower than the critical threshold, the MMSE-DFTalgorithm is used for the channel estimation, and when SNR is higher than the critical threshold, the DCS-SOMPalgorithm is applied to the data reconstruction and the recovery of channel impulse response matrix. Simulationresults show that when SNR is 1 dB-40 dB the proposed algorithm can reduce the mean square error （MSE） from2.95 dB to 15 dB, and improve the LED communication quality.

关 键 词：光通信 可见光通信 自适应信道估计 信噪比阈值 通信质量 

分 类 号：TN911.7[电子电信—通信与信息系统]