Timeout-Aware Inter-Queuing for QoS Provisioning of Real-Time Secondary Users in Cognitive Radio Networks

Assurance of quality of service (QoS) to secondary users in cognitive radio networks is a challenge as the secondary users have to use the spectrum on an opportunistic basis, which is random. To address this challenge, the secondary users are classified into four priority classes by maintaining a separate queue for each priority class. The assignment of channels to secondary users starts from the highest priority queue towards the least priority queue. Further, the QoS to real-time secondary users is improved by introducing timeout-aware inter-queuing (TAIQ), in which shifting of the secondary user is allowed from low-priority queue to high-priority queue when its time deadline is about to reach the time deadlines of its next high level priority queue SUs. The results showed that the proposed four priorities with timeout-aware inter-queuing mechanism give less blocking to real-time secondary users with respect to conventional real-time and non-real-time secondary users.