Impact of the primary resource occupancy information on the performance of cognitive radio networks with VoIP traffic

In this paper, the relevance of considering the primary network resource occupancy information on the admission criterion of new secondary VoIP sessions in cognitive radio networks (CRNs) is investigated. In particular, the performance of two different call admission control (CAC) strategies whose admission criterion is based either on the total number of primary and secondary sessions or only on the number of sessions of secondary users is compared. System performance is evaluated in terms of the most relevant quality of service metrics for VoIP traffic at both call and packet level. Numerical results clearly show that including primary resource occupancy information on the CAC strategy is an effective mean to improve system performance, especially for low to moderate traffic loads. For instance, assuming that voice toll quality is required, packet dropping probability is reduced more than 30% when primary resource occupancy information is additionally used on the CAC strategy.