Providing Some Minimum Guarantee for Real-Time Secondary Users in Cognitive Radio Sensor Networks

Previous studies of real-time traffic in Cognitive Radio Sensor Network (CRSN) were done using reservation-based method and absolute priority method. These studies were done under the assumption that primary user's traffic arrive at a low rate. However, under high arrival rate of primary user traffic, real-time secondary user traffic is starved. In this paper, we developed an analytical model of source-to-sink delay in a Cognitive radio sensor network (CRSN) that differentiates the service of users into primary and secondary and further partitions secondary user's traffic into real-time and best effort. During service, primary traffic is given priority over real-time secondary user traffic which in turn has higher priority over best effort secondary traffic. Furthermore, a threshold is introduced on the number of primary user packets served to reduce the starvation of real-time secondary users under high arrival rate of primary user traffic. The numerical results obtained from the derived models show that real-time secondary users experience a reduction in source-to-sink delay as a result of introducing a threshold on the number of primary user packets served without over degrading the service of primary user traffic.