A distributed multi-objective optimisation framework for energy efficiency in mobile backhaul networks

Mobile data traffic is experiencing unprecedented growth rates due to the rapid proliferation of devices such as smart phones and tablets. Improving the efficiency of mobile networks, both in terms of services and energy consumption, is thus critical for sustaining this growing demand. While the adoption of new technologies such as small cell networks and cognitive radio reduces deployment and operational costs, challenges remain on how the data traffic can be efficiently processed and transported over the mobile backhaul network. In this paper, we aim to improve the energy efficiency of mobile backhaul networks, while simultaneously balancing the traffic load on its various backhaul nodes, in order to maintain the required service quality. We first formulate a multi-objective optimisation problem, then propose a distributed traffic control algorithm to solve it. We show the convergence of the algorithm through Lyapunov analysis; and numerical simulations illustrate the results. We find that the traffic dynamics pose notable challenges for operators to plan, design and operate mobile backhaul networks when aiming to achieve the desired energy-performance tradeoffs.