MAC layer Cooperation Analysis in Cognitive Wireless Networks

Cognition and cooperation are two concepts closely connected in Cognitive Wireless Networks. In such distributed networks, where there is not any central node responsible for retrieving/forwarding the information from/to all the users, the monitoring of the spectrum availability must be carried out also in a distributed fashion. However, there exists a trade-off between the amount of monitoring information shared among the users and the overhead introduced to the network, particularly when users are equipped with a single antenna. As primary users may suddenly transmit on any licensed channel, all secondary users should monitor periodically alternative idle channels where to resume the ongoing communications in case such a situation occurs. In this paper we analyze the minimum spectrum monitoring frequency required for users to have a number of alternative idle channels.