Delay analysis of multihop cognitive radio networks using network of virtual priority queues

In this paper, we characterize the average end-to-end delay and maximum achievable per-node throughput in an opportunistic secondary cognitive radio network coexisting with a primary network where both networks consist of static nodes that use random medium access schemes. Assuming an ideal sensing mechanism, we first model the secondary network as a two-class priority queuing network and use queuing approximation techniques to obtain a set of relations involving the mean and second moments of the inter-arrival time and service-time of packets at a secondary node. Then, utilizing these parameters in an equivalent open G/G/1 queuing network, we obtain closed form expressions for average end-to-end delay of a packet in the secondary network and the maximum achievable throughput of a secondary node. The results are validated against extensive simulations.