Authors: S. Elsayed Saad; Ibrahim F. Tarrad; A.A. Ammar
Addresses: High Institute for Engineering and Technology, Al-Obour, Cairo, Egypt ' Faculty of Engineering, Al-Azhar University, Cairo, Egypt ' Faculty of Engineering, Al-Azhar University, Cairo, Egypt
Abstract: Cognitive Radio Networks (CRNs) have been recognised as an effective approach for overcoming the problem of spectrum scarcity caused by development of wireless applications. This paper proposes a channel access model for prioritised cognitive radio networks using an iterative method of queuing theory. This model is applicable for multiple channels and multiple priority classes of secondary users. The proposed model formulates an accurate closed form of an expected waiting time in the queue, an expected number of users in the queue, an expected waiting time in the system (waiting time in queue and service time), and an expected number of users in the system. The results show that the waiting time in the queue and the waiting time in the system compared to the basic model without priority will be improved by 58.3% and 20.8% respectively for class one secondary user. The results also show that the waiting time in the queue and the waiting time in the system will be improved by 16.7% and 5.8%, respectively for class two secondary users. The proposed model investigates the desirable schedules of primary and secondary users.
Keywords: cognitive radio; spectrum access; non-preemptive priority; queuing theory.
International Journal of Wireless and Mobile Computing, 2018 Vol.15 No.4, pp.351 - 358
Received: 03 Nov 2017
Accepted: 26 Aug 2018
Published online: 26 Dec 2018 *