A two-step resource allocation in multiuser OFDM-based cognitive radio systems

Development of fair and efficient algorithms for resource allocation to secondary users (SUs) is one of the key issues in the design of cognitive radio (CR) systems. In this paper, we present a two-step resource allocation solution for multiuser based CR systems employing orthogonal frequency division multiplexing (OFDM). The solution allocates the subcarriers to SUs in the first step, considering proportional fairness. In the second step, the solution allocates the power to the subcarriers to maximize sum capacity of all SUs, without causing excessive interference to the primary users (PUs). Simulation results and performance analysis show that our proposed solution can offer a beneficial efficiency-versus-fairness tradeoff, while largely reducing computation cost compared to the existing solution.