Abstract
Spatial and temporal variations in the available spectrum for cognitive devices add additional complexity in designing a medium access strategy for cognitive radio (CR) networks. To ease this complication, a common control channel (CCC) is often used as a common platform to exchange control messages, so the CR users can make decisions concerning resource allocation. Much of the literature in this area opts for forming groups and negotiating a CCC from the available channels rather than considering a dedicated common control channel. However, if a primary user appears on the CCC, all the CR users have to vacate that channel and negotiate another CCC, and thus overhead continues to grow with an agile primary network. We propose a medium access control protocol that can work in the absence of a CCC and reduce the possible overhead to a greater extent. In our proposed protocol, CR users take advantage of similar spectrum availability in their neighborhood for resource utilization. We also propose a contention-based spectrum allocation mechanism that works in a distributed manner over different available channels. Simulation results show that this approach can reduce broadcast overhead significantly while maintaining connectivity success similar to its counterparts.