车间2×2 MIMO可见光通信模型优化研究

Optimization of 2×2 MIMO Vehicular Visible Light Commonications Model

本文提出了一种车与车空间分集接收的2×2多输入多输出(Multiple Input Multiple Output,MIMO)可见光通信模型.该2×2MIMO模型以基于市场加权灯束模型的汽车前照灯作为2个发射器,以光电探测器作为2个接收器,分别考虑了沥青和水泥两种类型路面对接收光功率的影响,对2个光电探测器接收的信噪比进行最大比合并处理.在不同类型路面以及不同光电探测器高度下研究了两车相对位置与光电探测器接收到的光功率之间的关系,并分析了光电探测器最优接收高度时车间通信范围和误码率性能之间的关系.研究结果表明:真实路面反射对通信质量有较大影响,在评估通信质量时不可忽略,且沥青路面对通信质量的影响大于水泥路面.当两个光电探测器安装在接收信号车辆尾部距离路面的垂直高度为0.2 m,误码率小于10^(-4)时,以5 Mbps的数据速率车间通信距离可以达到28 m.相比于同样条件下单输入多输出(Single Input Multiple Output,SIMO)可见光通信模型,本文模型不同车间通信距离下的垂直平面宽度最大增加了3 m,车间通信距离至少增加了0.5 m.本文提出的可见光通信模型考虑了真实汽车前照灯模型和路面反射特性,为车间2×2MIMO可见光通信的研究提供了可靠的理论依据和实验指导.

A 2×2 multiple input multiple output(MIMO)vehicular visible light communication model with spatial diversity reception is proposed in the paper.In the model,the automotive headlights based on the market-weighted model are considered as two transmitters and the photodetectors as two receivers,and the influence of asphalt road and cement road on the received optical power is considered respectively.The signal to noise ratio received by two photodetectors is combined by maximum ratio processing.The relationship between the relative position of two vehicles and optical power received by photodetectors under different road types and photodetectors'heights is studied.The relationship between com-munication range and bit error rate performance at optimal photodetectors'height is analyzed.The study results show that the reflection of real pavement has a great influence on communication quality,which cannot be ignored when evaluating communication quality,and the impact of asphalt pavement on communication quality is greater than cement pavement.When the two photodetectors are installed at the rear of the vehicle receiving the signal,the vertical height from the road sur-face is 0.2 m and the bit error rate is less than 10^(-4),the communication distance can reach 28 m at a data rate of 5 Mbps.Compared with the single input multiple output(SIMO)vehicular visible light communication model under the same condi-tion,the maximum vertical plane width increases by 3 m under different communication distances,and the communication distance increases by at least 0.5 m.The visible light communication model proposed in the paper takes into account the real automobile headlamp model and road reflection characteristics,providing a reliable theoretical basis and experi-mental guidance for vehicular 2×2 MIMO visible light communication research.