Channel Assignment in Cognitive Radio Networks: A Joint Utility and Stable Matching Approach

Channel assignment is a key problem in Cognitive Radio Networks. The channels are leased to the secondary users when the licensed or primary users are OFF, provided that the secondary users will leave those channels as soon as the primary users are reactivated. Therefore, to achieve a high performance of the network, we should lease a channel to a secondary user while both of them achieve the best possible utility. In this paper, we first define two utility functions, one for the secondary user and another for the channel. Then, in the pre-matching stage, we find a trade-off between these two utilities for each secondary user-channel pair by defining a joint utility function. Next, using the maximal secondary user utility and the maximal channel utility corresponding to the trade-off point as a measure of their preference for each other, we match secondary users and channels to each other by the Gale-Shapley stable marriage algorithm. We also obtain the optimal transmission power of the secondary user and the optimal bandwidth of the channel. Finally, we provide numerical results by computer simulation of our scheme.