Backhaul Design and Controller Placement for Cooperative Mobile Access Networks

Exploiting base station cooperation in wireless mobile access networks leads to benefits in wireless transmission capacity, inter-cell interference management, and cell edge user experience. The clustering of cooperative Base Station (BS) sets, necessary for achieving the desired wireless performance, poses several challenges in the backhaul architecture design. This paper addresses the problem of placing and connecting controller/processing nodes within the backhaul infrastructure, which coordinate and/or process signals of cooperating base stations. We formulated a Mixed Integer Linear Programm (MILP) for this problem and a heuristic algorithm that approximates the optimal solution. While the heuristic's solution quality is close to the optimum, the runtime and memory requirements are multiple orders of magnitude lower compared to solving the MILP. This advantage allows to use the proposed heuristic either for backhaul/core network pre-planning or for on-the-fly network reconfiguration during ongoing mobile network operation.