可见光MIMO通信中金字塔型接收机角度分集优化

Optimization of angle diversity for a pyramid receiver in MIMO visible light communications

为增强室内可见光多输入多输出(MIMO)通信系统的空间复用增益并降低信道相关性,提出一种优化的金字塔型角度分集接收模型.首先采用光线追踪分析方法建立室内系统模型及码间干扰模型,分析了MIMO系统接收平面码间干扰(ISI)以及光功率分布.在此基础上,对接收机分集维度、旋转角、倾斜角以及发光二极管(LED)和光电检测器(PD)的空间布局等参数通过控制变量法进行了优化.数值仿真结果表明,最佳的分集维度是4×4结构;同时,对于传输速率为100Mbps的4×4MIMO系统而言,当水平旋转角为45°,倾斜角为50°和LED间距为1.7m时,系统可获得最大信道容量.通过对分集参数的优化,可有效增强信道分集增益,减少码间干扰,提升接收系统整体性能.

In order to enhance the spatial multiplexing gain and reduce the channel correlation in indoor visible multiple input multiple output(MIMO)communications,an optimized pyramid angle diversity receiver model is proposed.Ray tracing method is adopted to establish the channel model and intersymbol interference(ISI)model.The ISI and optical power distribution of the receiving plane in MIMO system are analyzed,respectively.The diversity dimension,rotation angle,tilt angle,and spatial layout of light-emitting diodes(LEDs)and photodetectors(PDs)are optimized by the control variable method.The numerical results show that the best diversity dimension is the 4×4 structure.Meanwhile,in the case of the transmission rate of 4×4 MIMO system is 100 Mbps,the LED spacing is 1.7 m and the horizontal rotation angle is 45°and the tilt angle is 50°,the channel capacity can reach the maximum value.It is verified that the spatial multiplexing gain can be effectively enhanced,and the overall reception performance can be improved via optimizing the diversity parameters.