Achievable energy efficiency resource allocation in OFDM system with mixed traffic

Energy efficiency is becoming more and more important to the development of wireless communication. In this paper, we study energy-efficient resource allocation in an Orthogonal Frequency Division Multiplexing (OFDM) system with mixed traffic. Considering both the energy efficiency and spectral efficiency, we model the allocation of sub-carriers and power as a mixed integer nonlinear programming (MINLP) problem maximizing the utility per Watt. The formulated problem is non-convex and is computationally forbidden. To simplify the solution of the problem, a two-step resource allocation (TSRA) algorithm is proposed. In the first step, we simplify the problem to a convex one and obtain the sub-carrier allocation using Karush-Kuhn-Tucker (KKT) conditions. On this basis, we solve the power allocation problem in the second step by transforming it into a parametric programming problem and applying Dinkelbach´s theory. Simulation results show that our algorithm can provide 28% energy efficiency improvement compared to conventional algorithms.