Common control channel design for cognitive radio wireless ad hoc networks using adaptive frequency hopping

Cognitive radio (CR) technology enables the opportunistic use of the portions of the licensed spectrum by the CR users, while ensuring low interference to the primary user (PU) activity in the licensed bands. The spectrum is sensed locally by the CR users, and a specific channel that is acceptable to both the end nodes of the communication link is chosen. However, this necessitates a common control channel (CCC) for exchanging the sensing information and reserving the channel before actual data transfer. In this paper, a common control channel design for CR ad hoc networks is proposed, called as adaptive multiple rendezvous control channel (AMRCC) based on frequency hopping. Our scheme is scalable, and allows continuous connectivity between the CR users under dynamic PU activity. The contribution made in this paper is threefold: (i) a frequency hopping scheme is proposed that allows altering the hopping sequence based on the PU activity in the channels, (ii) a simple and low-overhead procedure is developed to aid new node-join and leave events, and (iii) a slot duration optimization is given that avoids a significant performance degradation with the number of available channels. Performance evaluation proves that our solution achieves better performance than the other classic CCC solutions in terms of time to rendezvous (TTR) and the resulting throughput, specifically in CR ad hoc networks.