Max‐min energy‐efficient subchannel assignment and power allocation in interference‐limited OFDMA heterogeneous networks with QoS guarantee

Abstract

Abstract This paper investigates fairness among all small‐cell users (SCUs) in terms of energy efficiency for the uplink transmission of interference‐limited orthogonal frequency‐division multiple access–based heterogeneous networks. Each SCU is treated by a minimum data rate. In addition, a maximum tolerable interference for the macro base station has been considered. The resulting resource allocation problem is formulated as a nonconvex mixed‐integer nonlinear problem. In order to solve the mixed‐integer nonlinear problem, the subchannel assignment and the power allocation are applied separately; an efficient subchannel assignment algorithm has been proposed where the co‐tier and cross‐tier interference in the most general form has been taken into account. Then, to solve the power allocation subproblem, an iterative algorithm has been proposed by applying generalized fractional programming and sequential convex programming when a specified subchannel assignment is in hand. Performance of the proposed model has been evaluated, and simulation results indicate a fair resource allocation with a very high energy efficiency among SCUs comparing the state‐of‐the‐art solutions.