Joint dynamic access points grouping and resource allocation for coordinated transmission in user-centric UDN.

We consider the resource allocation problem in user-centric ultradense network, where each user equipment (UE) is served by its own access points group (APG), and the APG will be dynamically adjusted to support UE's movement. In this context, our scheme is to jointly design dynamic APs grouping and the resource allocation for coordinated transmission in user-centric ultradense network. First, a user-centric dynamic APs grouping approach is considered, where the APGs are formed based on cooperation benefits that UEs experience to different access points (APs). Accordingly, due to resource allocation constraints unbounded among the overlapped APGs, which result in the resource allocation optimization problem being nonconvex. To address this issue, the resource allocation problem is divided into the subchannel (SC) allocation subproblem and the power allocation subproblem. With the SC allocation results, an iterative power allocation algorithm is carried out over all SCs at each AP to get an optimal power allocation. The performance of the proposed scheme is also demonstrated through simulations.