ABSTRACT
This chapter presents a carrier sense medium access with collision avoidance (CSMA-/CA)-based MAC protocol called CM-MAC for cognitive radio ad hoc networks (CRAHNs). The protocol involves spectrum sensing in the handshaking procedure, and thus, the spectrum information updates on Cognitive radios (CRs) are highly dependent on the primary user (PU) traffic and the CR data traffic. Moreover, the effectiveness of CM-MAC is demonstrated through the analytical link throughput performance. There are two advantages to using a common control channel (CCC) in CRAHNs. First, possible collisions of control frames and data frames can be avoided. Second, when spectrum availability changes, assigning a CCC can alleviate the communication efforts required to consult other CRs in a new spectrum band for exchanging control information. Since CRs in a CRAHN are able to move in the network and cause significant interference to PU traffic, it is important to consider the case that CRs may move into a primary exclusive regions.
