Dynamic Spectrum Access with Prioritized Secondary Users in Cognitive Radio Networks

Dynamic Spectrum Access (DSA) has got tremendous attention and research, but most of the existing dynamic spectrum access schemes assume that all Secondary Users (SUs) are of the same priority. In this paper, prioritized SU traffic is considered. The SU traffic in the system is classified into two priority classes based on Quality of Service (QoS) requirements, namely delay-sensitive SU and delay-insensitive SU. Considering that the higher priority users can preempt the transmission of the lower priority users, we develop the analytical model by applying Preemptive Repeat Priority (PRP) M/G/1 queueing theory. Based on the model, we evaluate the overall system time of the prioritized SUs and separately design different spectrum access strategies for them. The results demonstrate that the proposed dynamic spectrum access schemes can simultaneously reduce the overall system time of SUs with different priority classes significantly.