Design and analysis of an under water visible light MIMO communication system with a camera receiver

In this paper, design, implementation and analysis of a new underwater multiple input multiple output visible light communication (VLC) system is presented. The VLC system consists of a transmitter, water channel, and a receiver. The transmitter is made out of light emitting diodes (LEDs'), while a camera based architecture is adopted at the receiver. We present a possible system design and characterize the channel for symbol detection. At the training phase, the underwater channel is characterized using a channel matrix, which presents the relationship between the multiple input LED states and the pixel values of the frame in the video stream obtained from the camera receiver. Thereafter the inverse model of the system is obtained. Then symbol detection is carried out by analysing consecutive frames of the real-time video stream. Also we analyse the performance of this system in terms of the bit error rate (BER), bit rate, behaviour of the system at different transmission distances, and present results using the experimental setup. From our study, it was realised that, reasonable BER performance can be achieved using the proposed system designs at low and medium transmission distances compared to most of the existing underwater communication systems.