A Power Constrained Multi-Channel MAC Protocol for a Cooperative Spectrum Access

The Cognitive Radio (CR) is a recent technology that aims at increasing the spectrum utilization under the current static spectrum management. With appropriate CR MAC protocols, the unlicensed users, also called secondary users (SUs), are able to access the unused portion of spectrum in an opportunistic way. These protocols should also provide a coordinated access between the SUs and protect the licensed users (or primary users PUs) from the induced interference. In this paper, we propose a novel multi-channel cognitive MAC protocol based on a cooperative spectrum access, and which enhances the throughput of the cognitive radio network (CRN) subject to a SU transmit power constraint. Our protocol, the RMC-MAC protocol, introduces a new reactive sensing period and a novel recovery scheme to instantly detect the presence of a PU while preserving the continuity of the SU transmission. Simulation results show that the bandwidth utilization is increased up to 25% as compared to the buffering based MAC protocol and up to 45% as compared to a more typical protocol without any handoff mechanism. The forced termination probability is also considerably reduced which improves the overall network throughput. KeywordsCognitive radio networks, detection scheme, opportunistic spectrum access, cooperative spectrum access, reactive sensing period, multi-channel MAC protocol.