Adaptive Uplink MAC for CDMA-Based Cognitive Radio Networks

This paper proposes an adaptive code division multiple access (CDMA) based cognitive medium access control (MAC) scheme for uplink cognitive radio networks. The proposed scheme addresses the joint channel sensing and data transmission, power and rate assignments, and long-term fairness. Under our proposed scheme, the secondary users (SUs) can adaptively select either the intrusive spectrum sharing or non-intrusive spectrum sharing operations to transmit data to secondary basestation (SBS) based on the channel utilization, traffic load, and the interference constraints. Our proposed scheme enables the SUs to efficiently utilize the frequency spectrum which is licensed to the primary users (PUs) while rigorously limiting the interference to the PUs. Also conducted are simulations to validate and verify our proposed scheme.