Parallel Link Rendezvous in Ad Hoc Cognitive Radio Networks

A Cognitive Radio (CR) network seeks to access and utilize the unused license spectrum portions. These portions have dynamic behavior that introduces challenge for the CR user to allocate and rendezvous on the same portion. In CR Ad-hoc Network (CRAHN), there is difficulty of maintaining a Common Control Channel (CCC); for that, CRAHN requires a protocol able to guarantee users rendezvous without CCC. This paper proposes a distributed Medium Access Control (MAC) protocol using the concept of Balanced Incomplete Block Design (BIBD) to achieve a rendezvous channel without a CCC or synchronization. If the channels of a network are assigned to the BIBD elements and the searching sequence to the BIBD block, there is a guarantee of a rendezvous in at least one channel for each searching sequence. Simulation results confirm that the protocols outperform other protocols with respect to Time to Rendezvous (TTR), channel utilization, network throughput, and percentage of collisions between the SU and the PU network. In addition, the protocols fairly distribute the network load on channels, and share the channels fairly among network nodes.