Performance Evaluation of Cognitive Radio VoIP Users in Fading Environment

In this paper we investigate three channel allocation algorithms for multi-channel cognitive radio networks: SNR-based allocation (SA), queue-based allocation (QA), and queue-based SNR-aware allocation (QSA). The efficiency of the proposed algorithms is investigated for VoIP cognitive radio users (CRs). The resource allocation in the SA and QA schemes is performed based on the channel quality status seen by each CR and its queue length, respectively. The channel allocation in the QSA scheme is based on both the queue length and the SNR status. The mean packet loss rate (PLR) as the main quality-of-service (QoS) parameter is scrutinized for each algorithm. Novel analytical structures together with new analyses are developed, by which the level of provisioning QoS of VoIP traffic in each of the proposed algorithms can be evaluated. Numerical results and comparisons are also presented. In particular, the QSA algorithm is shown to present the best QoS level and yield the least PLR among the three allocation schemes.