Opportunistic splitting algorithm for underlay cognitive radio networks

Dynamic Resource Allocation (DRA) is one of the essential enabling techniques for Cognitive Radio (CR) technology. In this paper, the Opportunistic Splitting Algorithm (OSA), previously proposed for conventional systems, is exploited to allocate the resources in a CR system. The CR system is allowed to underlay the sub-carriers of an OFDM-based primary system. Several modifications are proposed to the OSA to suit a CR system without losing the main advantages of the OSA. The proposed CR-OSA can allocate resources without the need of a centralized controller and the decision is taken on the average in less than 2.5 mini-slots regardless of the number of users in the CR system. These results are shown analytically and using simulations. Different scenarios based on the nature of the rate needed by the CR system are also compared.