Cooperation Strategies and Optimal Precoding Design for Multi-User Multi-Cell VLC Networks

This paper investigated the comparative performance of different cell cooperation strategies for multi-cell multi-user visible light communications (VLC) networks. In practical deployment of VLC, multiple LED arrays are deployed to provide sufficient illumination for large rooms/offices. As a consequence, multi-cell configurations are a natural progression for indoor VLC networks. In this study, to support multiple users simultaneously by means of precoding technique, each VLC cell is formed by 4 separated LED arrays. In such multi-cell networks, a user can be severely interfered not only by the signals that are intended to other users within the cell (intra-cell interference) but also by the signals for users of the other cells (inter-cell interference). In order to suppress these interferences, cell cooperation can be applied for precoder designs. We consider several strategies of cell cooperation and investigate the design of optimal precoding matrix corresponding to each cooperative strategy to maximize the achievable sum capacity of users. Comprehensive numerical results are shown to compare the performance of the considered cooperation strategies.