Experimental Design And Data Processing Of Visible Light Communication System Based On MIMO

Visible Light Communication(VLC) which combines lighting and communications does not require electromagnetic spectrum or certifications. This technology is more confidentiality and safer to human health. With the characteristi of high-speed switching response, it provides a new wireless access methods by modulating signals to the LED lights which are used as the transmitting antenna of the system. Compared with the Single-Input Single-Output(SISO) VLC system, the one based on Multiple-input Multiple-output (MIMO) can increase the channel capacity and the utilization of the spectrum by the mode of spatial multiplexing but without increasing the bandwidth of the antenna and the transmission power. For now, the research on MIMO VLC is mainly in the aspect of theory, and system design is still in the primary stage. At the same time, there is few papers can give a solution to the Inter-Symbol Interference (ISI) problem in MIMO VLC system. So, this issue needs further discussion and study.In this paper, the main contents of the research on VLC system based on MIMO are presented as follows:(1) It introduces the principle and the hardware components of VLC system based on MIMO, and analyses the differences between traditional fiber optic communication and electromagnetic communication. Then proposed a method of bit synchronization applied for VLC system based on MIMO. This method is a combination of MIMO and SISO system, and easy to implement.(2)It describes the importance of eliminating background light in the algorithm which uses the channel matrix to recover the information, and designs a algorithm of Maximum Likelihood(ML). Then it gives the design method for training sequence of the two algorithm in detail.At last, by analyzing the experimental data, it presents some skills to improving the performance of the ML method and lists the advantages and disadvantages between the two ways.(3)By analyzing the character of channel in VLC system based on MIMO, it proposes a way to achieve channel equalization, and gives the design method for training sequence and discusses the pros and cons about the channel equalization technology.At last, by simulation, the results show the effectiveness of this method.