Performance analysis of indoor MIMO visible light communication systems

In this paper, we study the performance of Repetition Code (RC) and Spatial Multiplexing (SMP) applied to Visible Light Communication (VLC) in indoor scenarios with non-direct line-of-sight (LOS) characteristics. Considering a VLC MIMO system with 4 transmitters within a typical 5 m × 5 m × 3 m room, by means of simulation, we investigate the distribution of Bit-error-rate (BER) when the receiver moves around the room. For various transmitter separations, the normalized area at which the system performance does not satisfy a required BER level is illustrated. The optimal values of transmitter separation for RC and SMP are 1.5 m and 3.5 m, respectively. Comparing between RC and SMP, the results show that RC outperforms SMP at low spectral efficiency. However, at relatively high spectral efficiency RC does not perform well since it requires a very high constellation size, while SMP with its spatial multiplexing gain can offer a much better performance.