Sum throughput maximization in multi-user OFDMA-based cognitive radio systems with secondary users rates requirements guarantee

In this paper, the resource allocation for OFDMA-based cognitive radio (CR) system is considered. We propose a two-step resource allocation algorithm that maximizes the sum throughput of the system while satisfying the quality of service (QoS) requirements for guaranteed users (GUs). By the first step, the sum power of the guaranteed users is minimized as the guaranteed rate is provided. By the second step, the remaining resources are distributed among all users so that the sum throughput is maximized. In both steps, power allocation is performed in a way that the adverse interference on the primary users (PUs) is avoided. Simulation results show that the proposed algorithm is highly efficient in terms of rate guarantee for GUs and sum throughput maximization.