Training Resource Allocation for User-Centric Visible Light Communication Cooperation Transmission

User-centric applications through visible light communication cooperative transmission constitute an architecture that has emerged in recent years. The resulting user-dependent cooperative clusters arc observed to inevitably overlap. The training signals transmitted from the access points (APs) in each cluster or from the users who select identical APs in their clusters should be mutually orthogonal to avoid pilot contamination. Herein, we study the orthogonal training resource allocation problem for user-centric cooperative networks. Further, we formulate a joint pilot allocation and the user equipment (UE) selection problem to maximize the number of admitted UE with a fixed number of pilots. Finally, the analysis and numerical results denote a remarkable improvement when compared with the existing scheme and denote that the proposed method can effectively avoid pilot contamination and improve the utilization of training resources.