Analysis of an interruption-based priority for multi-class secondary users in cognitive radio networks

Abstract

In cognitive radio networks, delay requirements for secondary users are not homogeneous. In this paper the secondary user traffic is classified into M prioritized classes based on delay requirements in order to support the delay-sensitive secondary user applications. Moreover, after each interruption from the primary user the priority of the secondary user increases within the same class in order to reduce the handoff delay. A mixed preemptive/non-preemptive resume priority M/G/1 queuing model is used to analyze the multiple spectrum handoffs. The analytical results are applied to evaluate the latency performance of the proposed system and compare it with existing spectrum handoff systems for prioritized and unitary secondary user networks. This comparison is performed based on the target channel sequences mentioned in the IEEE 802.22 wireless regional area networks standard. Numerical results show that the proposed system outperforms existing systems in terms of average handoff delay and extended data delivery time under various traffic parameters. Then, to reduce the average extended data delivery time, a classifying technique for the secondary users with the same delay constraint is suggested, which assigns the priority based on the arrival rates. Simulation results are given to validate the analytical results.