Distributed RAN and backhaul optimization for energy efficient wireless networks

In this study, we address the problem of minimizing the energy consumption in future 5G networks by means of a joint optimization of radio access network (RAN) and multi-hop wireless backhaul network. The objective of the optimization is to operate the network with the smallest set of base stations while meeting the quality of service (QoS) requirements of users. We first pose the optimization problem as a convex optimization problem. We use a Lagrangian decomposition method to separate the problem in smaller subproblems, which are then solved using minimax primal-dual optimization in a distributed manner. By using the proposed method both the primal and dual problems can be solved at each base station with minimal information exchange between the neighboring base stations. Therefore, the solution proposed is suitable for solving the problems of similar nature in a completely distributed manner in large-scale ultra-dense networks (UDNs) with wireless backhaul infrastructure, which are extensively discussed in the context of 5G.