Call Admission Control Strategy for Cognitive Radio Networks with VoIP-Traffic

In this paper, a novel call admission control (CAC) strategy for a buffered cognitive radio network (CRN) with voice over Internet Protocol (VoIP) traffic is proposed. The main idea of the proposed CAC strategy relies on reducing the weight of the current number of secondary VoIP sessions in the admission/rejection decision criterion, which can potentially allow more efficient spectrum usage. To show this, the maximum VoIP Erlang capacity achieved by the proposed CAC strategy is calculated. Compared to the conventional (occupancy-based) CAC strategy, our proposed "differentiated resource occupancy-aware" CAC scheme increases Erlang capacity without an important increase in the system complexity cost. This indicates that in a CRN with VoIP traffic, system capacity not only depends on the total number of busy channels but also on the proportion of busy channels that are used by primary users.