Vulnerabilities of cognitive radio MAC protocols and countermeasures

Cognitive Radio (CR) is a promising technology for opportunistically accessing underutilized licensed spectrum to achieve higher spectrum efficiency and communication throughput. These performance gains are contingent upon the efficient coordination of channel access to the idle portion of the spectrum, an operation performed at the Medium Access Control (MAC) layer. In this article we identify various vulnerabilities of state-of-the-art CR MAC protocols, exploited by selfish/malicious CR users for gaining an unfair share of the available network resources. Furthermore, possible countermeasures for detecting and mitigating these vulnerabilities are discussed.