强背景光下LED交通灯的可见光通信误码率分析

LED交通灯的可见光通信将成为室外智能交通系统的发展方向。为了研究和克服信道中强背景光噪声对LED交通灯的可见光通信系统的干扰,对其通信信道建立强背景光噪声模型,分别构建了脉冲位置调制(PPM)、扩频(Gold码)、Gold码+PPM三种不同调制下的通信系统。首先分析了强背景光的相关参数,然后对PPM、Gold码、Gold码+PPM三种不同调制下系统误码率性能进行了比较。结果表明,接收机的视场角越小,接收机的直径越小,则通信系统受到背景光噪声的干扰就越小;在相同检测面信号功率下,太阳直射背景光噪声比扩展背景光更加影响系统通信性能;在同一背景光下,误码率最低的是PPM调制,其次是Gold码,Gold码+PPM的系统误码率最高。以扩展背景光的误码率达到10~(-4)作为参考,PPM通信系统分别比Gold码、Gold码+PPM通信系统低0.125和0.5 W的检测面信号功率。

Research on visible light communication's BER of LED traffic light under strong background noise

LED traffic light's visible light communication may become the good choice for the outside intelligent transportation system.In order to research and overcome the strong background noise's interference on LED traffic light's visible light communication, a strong background noise model for its communication channels is established.Under three different modulations which are PPM, Gold and Gold+PPM, communication system models are established.Firstly, the relative parameters of strong background light are analyzed, and then the system's BER qualities are compared under PPM, Gold and Gold+PPM.The results show that the smaller field of view of the receiver, the smaller the diameter of the receiver, the smaller interference of the communication system by the background light noise.When detection signal power is the same, the background noise from directed sun light is more influential for system's communication qualities than extension background light.Besides, under the same background noise, the lowest BER is PPM.Gold's BER is middle while system BER of Gold+PPM is the highest.Take extension background light's BER as a reference, when it is 10-4, PPM communication system's detection signal power is 0.125 W and 0.5 W lower than those of Gold and God+PPM, respectively.