Study On Application Of Indoor Visible Light Communication System Utilizing LED

With the rapid development of mobile phones, tablet PCs and other intelligent terminal equipment, the demand of the radio access network is rising up. And the shortage of the radio spectrum resources will inevitably influence the development of radio access networks. Because the visible light spectrum is not within the conventional communication, and LED has fast response speed, high speed light twinkling can be utilized to transmit signal. So visible light communication combined with the lighting and communication will produce high research value and broad application prospects.This paper focuses on some issues which will be encountered in practical applications of visible light communication system. The work are as follows:(1) Considering the optical characteristics of system and indoor environmental factors, a visible light communication channel model is established based on the classical channel model. And the details, which are on the number of light reflections and the relative position of the devices and so on, are optimized. Four indicators are established to make sure channel performance: the receiving optical power distribution, the channel impulse response, RMS delay spread, 3dB bandwidth.(2) The LED arrays of visible light communication system are simplified to varying degrees. The influence of the source simplification to system is analyzed by simulation. The results show that all modeling schemes provide approximately same power distribution, and the difference in modeling schemes does not yield notable impact on the received optical power. There is a significant effect on the RMS delay spread of the distribution. Especially the location of minimum is changed. The channel impulse response delay spread significantly reduced. Impact on 3dB bandwidth depends on the number of reflections and the position of the receiver.(3) This paper analyze the influence of correlation on the system channel capacity of MIMO channel space theoretically, and the impact of spatial correlation parameters are determined. Then formulas are derived. The relationship between spatial correlation with these parameters is clear. Through simulation analysis, spatial correlation of MIMO channel in indoor visible light communication decreases with increasing distance of PDs and LEDs, increases with the increasing distance between LED and PD.Study shows that, in a visible light communication system, the location of the transmitter and receiver positions relative to each other and the room has a great impact on system performance. The internal structure of the LED arrays also has a great influence on the accuracy of the channel model. The study of these problems on practical application of visible light communication plays a certain reference value.