A MAC protocol for cognitive radio networks with reliable control channels assignment

In cognitive radio network, control information dissemination is critical. Secondary users need to exchange control information for utilizing the available channels efficiently, to maintain connectivity, to negotiate for data communication such as sender-receiver handshakes, for neighbor discovery etc. In currently proposed MAC protocols for cognitive radio networks, control information are disseminated among users by using two famous mechanisms. The first one is the use of common control channel (CCC) and the second one is using channel hopping. However, both methods have their own drawbacks. The use of CCC may not be feasible in cognitive radio networks as the available channels, including control channel, are dynamically changing according to primary users activities. Channel hopping approaches cause significant amount of channel access delay which is known as time to rendezvous (TTR). In this paper, we propose a hybrid protocol of these two mechanisms. This hybrid protocol can maintain connectivity among secondary users by using multiple control channels. The use of multiple control channels guarantees the secondary users to be able to exchange control information in dynamic environment. Channel hopping is performed only for control channels, so it provides relatively small amount of channel access delay.