Interference coordination in CoMP with transmission scheduling and game theoretical power reallocation

In LTE-A (3GPP LTE-Advance) systems, CoMP (Cooperative Multi-Point) is adopted to enhance the performance of edge users. To maximize the edge user throughput, it is very crucial to properly determine the set of simultaneously served users in the same PRB (physical resource block) and cooperating BSs (base stations) for each selected user, as well as the transmit power of the BSs. In this paper, we first propose a simple scheduling algorithm to choose cell-edge mobile stations (MSs) and cooperating BSs for each PRB according to the RSRP (reference signal receiving power) of each MS, based on which the classic Water-Filling (WF) is applied at each BS to allocate transmit power over all PRBs. However, the objective of single cell power allocation is to maximize the throughput of each individual cell without considering interference among different cooperating BS sets. Therefore, we further formulate a power reallocation mechanism using non-cooperative game theory to refine the single cell WF result for interference coordination, which maximizes the total edge user throughput over all BSs and PRBs by properly taking CCI (co-channel interference) into account. Based on proving the existence of a unique Nash Equilibrium for the formulated game, we design an algorithm to find the Nash Equilibrium and demonstrate the performance gain through extensive simulation studies.