The Analysis Of Multi-path Characteristics For Indoor Visible Light Communication Channel Based On MIMO

Visible Light Communication(VLC) is a new type of optical communication technology which combines lighting and communications. The working principle is transmitting original electrical signal after coding and modulation by the characteristic of high-speed changing in brightness for LED lights. Multiple Input Multiple Output(MIMO) technology is combined with VLC can further increase the transmission bandwidth and communication rate. For now, the most research on MIMO VLC is mainly in aspect of improving transmitting rate, the less research on receiving characteristics and only considers the direct singal, but for receiving characteristics of multipath reflection for MIMO VLC are mentioned in few papers. So, It is necessary for this paper to discuss and research the simulation design for MIMO VLC system, multipath reception characteristics and effective solution to reduce multipath interference.In this paper, the main research work on MIMO VLC system is as follows:(1) It summarizes the working principle of Indoor visible light communication system, Then it expounds the hot technology in application, and by combining MIMO technology with VLC to analyse the model and advantages of current MIMO VLC system.(2) It establishes the MIMO VLC channel model and compares LOS link with non-LOS link. It determines the Lambert radiation model of white LEDs and analyzes the main characteristics of the detector. It introduces the channel parameters of MIMO VLC system by theoretically analysing the channel of SISO system. Finally, it makes modeling and simulation for MIMO VLC system.(3) Based on channel model of non-LOS link, the multipath receiving characteristics of MIMO VLC are analysed. It explores the causes of indoor multipath effects, and concludes the delay effect of multipath receving by the Indoor RMS delay distribution. The Indoor secondary reflection is under consideration, the different detector spacing, and the different receiving position, and the different rotation of receiver are analysed. So, we conclude the effect of detector spacing to receiving, the good reception area and effective rotation range of receiver plane.(4) Through analyzing the transmitter and receiver, it proposes the increasement of the period of the symbol transmission, the reduction of FOV, the introduction of decision feedback equalizer, and imaging receiving to weaken the multipath effect and analyses its feasibility in theory.