Joint cross-layer resource allocation and interference avoidance with QoS support for multiuser cognitive radio systems

We consider joint cross-layer resource allocation and inter-system interference avoidance in OFDMA-based multiuser cognitive radio (CR) systems, where the secondary users (SU) can share spectrum with the primary users (PU) without causing unacceptable interference. The objectives are to provide quality of service (QoS) to both real-time and non-real-time services for SUs, and optimize the system throughput. Based on aggressive sharing method, we quantify these goals by analyzing (i) a joint power control and interference cancellation to guarantee the performance in primary system; (ii) a cross-layer and dual problem method to transform MAC-layer QoS requirements to PHY-layer; (iii) the convex optimization to solve the problem of the system. The joint cross-layer solution is effectively achieved. Simulation results show that, compared to the conventional designs, the performance of proposed algorithm has significantly higher throughput and guarantees the performance in primary system and the QoS in secondary system as well.