A Discrete Time Queueing Model of Cognitive Radio Networks with Multi-Modal Overlay/Underlay Switching Service Levels
Attahiru Sule Alfa, Haitham Abu Ghazaleh, Bodhaswar T Maharaj · 2018
In an overlay/underlay cognitive radio network the channel can primarily be in two modes; occupied or unoccupied by a primary user, thus being in an overlay or underlay mode for the secondary user. However, during the underlay mode, the channel can present different capacities for the secondary user due to the varying primary user power levels. In this paper we introduce a method for modeling the multi-mode overlay/underlay levels for the secondary users and beyond the traditional 3-mode levels applied in the previous work. We essentially consider the case where the service levels of the channel can switch between the different modes, hence the channel availability and effective capacity to a secondary user are dynamic. We further present a discrete time queueing model that captures this scenario through the use of a discrete time Markov chain for analyzing the behavior of the system.