Modeling for spectrum handoff based on secondary users with different priorities in cognitive radio networks

Storaci-Cognitive radio (CR) can improve spectrum utilization by allowing the secondary users to temporarily access the primary user´s unutilized licensed spectrum. In fact, the secondary users´ delay requirements for data transmission would be not unitary. Some secondary users´ communications may be delay-sensitive such as VoIP service while some others may not such as uploading a large file. In this paper, secondary users are divided into two classes, class-1 secondary user denoted by SUI and class-2 secondary user denoted by SU2. Suppose SUI has a higher priority than SU2 to occupy the channels. In order to characterize the cumulative handoff delay of the secondary users with different priorities, a Markov transition model integrating with the preemptive resume priority (PRP) M/M/2 queuing network is investigated. The numerical results compare the handoff delay between the unitary secondary users and different priorities secondary users. The analysis of the admission region for SUI and SU2 can also facilitate the designs of admission control rules according to the latency delay requirements of different transmission services.