Photodetector Selection Aided Multiuser MIMO Optical OFDM Imaging Visible Light Communication System

Abstract

While playing an important role in radio frequency (RF)-based wireless systems, multiple-input multiple-output (MIMO) techniques have also found viable applications in visible light communication (VLC) systems. However, how to effectively reduce the inherent strong correlations between optical MIMO channels remains a typical issue for VLC. In this paper, we propose an MIMO-aided multiuser optical orthogonal frequency division multiplexing VLC system employing an imaging receiver (ImR). The proposed new scheme efficiently mitigates the optical MIMO channel correlations across the multiple photodetectors (PDs) of the same user equipment (UE) or those between different UEs, through invoking a new technique called photodetector selection (PDS). Two possible PDS designs, namely random PDS and modified maximum minimum singular value PDS are investigated. Through both analytical analysis and numerical simulations, we show that the proposed PDS-aided ImR system is capable of outperforming its conventional non-imaging receiver and non-PDS ImR counterparts, especially when UEs are close to each other. Results demonstrate that the proposed system offers a stably low bit error rate in most areas of the room.