Optimal Design of Energy- and Spectral- Efficient Wireless Backhaul Hetnets: Joint Load Balancing and Interference Management

We design an energy and spectral efficiency evaluation framework for wireless backhaul heterogeneous networks by jointing the load balancing and interference management. Instead of achieve rate in the conventional association, the proposed load balancing strategy utilizes the effective rate with imperfect channel state information, which comprehensively considers the number of associated users, bandwidth allocated to wireless backhaul, and the achieve rate. Moreover, the proposed interference management combines the reverse time division duplexing with power optimization control. The formulated problem is a multi-objective optimization problem, maximizing the energy efficiency and spectral efficiency simultaneously. With the scalarization approach, the original problem is then converted into a single-objective optimization problem, but it is still a nonconvex problem and generally NP-hard. To deal with it, a novel global lower bound maximization algorithm is developed, which iteratively solves the convex approximated problem until convergence. Finally, the convex approximated problem can be decoupled into smaller sub-problems by the alternating direction method to develop a distributed algorithm. Simulation results demonstrate that the proposed algorithms can significantly improve energy and spectral-efficient performance, and are superior to other algorithms.