Service Response Time of Elastic Data Traffic in Cognitive Radio Networks

Quality of service (QoS) support over cognitive radio networks (CRNs) is challenging due to the random spectrum availability. Elastic data traffic is a popular service whose service response time is an important QoS parameter. We analyze the mean response time of elastic data traffic service operating over a single channel time-slotted centralized CRN under three main service disciplines, namely, shortest processing time without preemption (SPTNP), shortest processing time with preemption, and shortest remaining processing time, in comparison with the processor sharing (PS) service discipline. It is shown that the SPTNP is a better choice over the PS service discipline when the traffic load is high, and that the preemption reduces the mean response time when the data file size (service time requirement) follows a heavy tailed distribution. The response time analysis can be used for call admission control to ensure service satisfaction.