Interference analysis for MIMO-OFDM based indoor visible light communication

Visible Light Communication (VLC) is an emerging wireless optical communication technology based on white light-emitting diode. VLC can fulfill lighting and communication needs; however, when illuminated, it produces reflections in the room, leading to a multipath effect that affects the signal quality of optical communication, thereby affecting user experience and system performance. This paper proposes a VLC system combining Multiple Input Multiple Output and Orthogonal Frequency Division Multiplexing (OFDM) using theoretical analysis. Firstly, the OFDM signal is modulated to compare the constellation distortion with the signal to noise ratio (SNR) of 25 dB and 30 dB. Experimental results show that the lower the bit error rate (BER), the more serious the distortion. Secondly, an optimal MMSE detection algorithm is proposed based on the minimum mean squared error (MMSE) signal detection algorithm and the least-squares method. Furthermore, the BER of the signal is verified by using zero forcing, MMSE and an optimized MMSE detection algorithm at the receiver of the system. The findings indicate that the optimized MMSE linear detection algorithm provides higher performance, with a BER of less than 10(-4) at 20 dB SNR. The overall experiment results illustrate that the proposed method in this work provides the system with low BER and high reliability, improving overall system performance.