Cognitive Radio Sensor Networks
Providing Some Minimum Guarantee for Real-time Secondary Users in Cognitive Radio Sensor Networks
Michael Okopa¹, Changa Andrew², Tonny Bulega²
¹ International University of East Africa, Faculty of Science and Technology, Kampala, Uganda
Previous studies of real-time traffic in Cognitive Radio Sensor Networks(CRSNs) were done using reservation-based method and an absolute priority method. In the absolute priority method, the traffic is classified as primary, real-time secondary user, and Best Effort (BE) secondary user. 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 study, we developed an analytical model of source-to-sink delay in a CRSN that differentiates the service of users into primary and secondary and further partitions secondary user’s traffic into real-time and BE. During service, primary traffic is given higher priority over real-time secondary user which in turn has higher priority over BE secondary traffic. In this model, 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. On the other hand, the primary user packets experience a higher source-to-sink delay. However, the reduction in source-to-sink delay experienced by real-time secondary user is lower than the increase in source-to-sink delay experienced by primary user traffic.