Band Synchronization in the Control Channel of Cognitive Radio Systems: A Collaboration Game

Control channel design is an important issue in cognitive radio systems. One potential approach is to use licensed frequency bands and opportunistic spectrum access for conveying control messages. Multiple frequency bands should be reserved to meet the requirement of high reliability for control channel. However, the availabilities of these bands may be asymmetric at the transmitter and receiver. A bad design of control channel may cause deadlock, e.g. the transmitter keeps transmitting at one band which is unavailable for the receiver. Therefore, band synchronization for control channel is studied to avoid deadlock and achieve reliable connection. The band synchronization is considered as a two-party collaboration game and is then studied using game theory. For one-stage case, conditions of Bayesian equilibrium are proposed and explicit expressions are obtained for two-band case. For multiple-stage case, a heuristic algorithm is proposed. Numerical results show that the band synchronization algorithms can achieve good synchronization probability and thus yield a reliable control channel.