Low complexity subcarrier and power allocation for utility maximization in uplink OFDMA systems

We consider the joint subcarrier and power allocation problem with the objective of maximizing the total utility of users in the uplink of an OFDMA system. Our formulation includes the problems of sum rate maximization, proportional fairness and max-min fairness as special cases. Unlike some previous algorithms, which are iterative and time consuming, our proposed one is non-iterative and with time complexity of only O(KN log₂ N), where K and N are the number of users and subcarriers respectively. We prove that it provides a solution that is Pareto optimal within a large neighborhood of itself. Besides, we derive an efficiently computable upper bound of the optimal solution. Simulation results show that our algorithm is nearly optimal.