Unsaturated Throughput Analysis of a Novel Interference-Constrained Multi-channel Random Access Protocol for Cognitive Radio Networks

Opportunistic access of licensed spectrum using a cognitive radio network (CRN) is getting research attraction due to its ability to improve utilisation of this scarce resource without affecting the primary users (PUs). To improve wide acceptability of CRN, it must be equipped with efficient protocols to deal with multiple primary networks to provision QoS guarantee for demand-driven applications by the secondary users (SUs). In this paper, an accurate unsaturated throughput analysis is presented for our novel CSMA/CA-based multi-channel cognitive radio medium access control (MCR-MAC) protocol. Developed by modifying the 4-way handshaking-based IEEE 802.11 DCF, MCR-MAC dynamically assigns contending SUs to free channels using an innovative random arbitration scheme while keeping cognitive interference to the PUs in check by attenuating the packet size. Not only has the analytical model covered the full spectrum, from very light load to saturation, extensive simulation results have validated the accuracy of the analysis.