Cooperating base station set selection and network reconfiguration in limited backhaul networks

Managing interference by Coordinated Multi-Point (CoMP) transmission/reception is an effective mechanism to achieve high data rates in future cellular networks, like Long Term Evolution (LTE)-Advanced. For CoMP, sets of Base Stations (BSs) have to be selected to jointly serve User Equipments (UEs). These sets are typically selected based on wireless characteristics only. However, using CoMP also poses strict capacity and latency requirements on the backhaul network, which are difficult to fulfill even with future optical technologies. Hence, these requirements additionally need to be taken into account when deciding which BSs jointly serve a given UE. We have developed a BSs selection heuristic for CoMP that takes into account both aspects: the wireless channels and the backhaul network status. This heuristic can also identify, for a particular wireless channel situation, which bottlenecks in the backhaul network make a desired BSs selection infeasible. We exploit this to dynamically adapt the backhaul network to the wireless requirements. We call this network reconfiguration. Our simulations show that the heuristic's solution quality is close to the optimum while execution time and memory consumption are reduced by multiple orders of magnitude compared to solving the problem via mathematical optimization. This allows real-world deployment of the heuristic. In addition, we simulate the network reconfiguration in a future backhaul network scenario based on Passive Optical Networks (PONs). The results illustrate how our approach helps to better exploit available backhaul resources.