Adaptive MIMO-VLC System for High Data Rate Communications

In this paper, we describe a high-speed indoor MIMO-VLC system that adapts the number of MIMO channels and data rate according to channel conditions at user locations. At each user location across the room, the number of MIMO transmission channels is varied (by grouping different transmitters and sending the same data stream), and the data rate on each channel group is then separately maximised. The system also employs the angle diversity receiver, zero-forcing MIMO equalisation and decision-feedback equalisation to mitigate spatial crosstalk and temporal interference. The performance of the proposed system is evaluated considering a practical indoor MIMO-VLC setup. For the configuration considered a peak overall data rate of 660 Mbps is achieved, and on average the overall data rate is 120 Mbps higher than a conventional spatial multiplexing approach. This shows the potential of this simple allocation scheme, compared with more complex precoding approaches.