Modeling and analysis of cognitive radio networks with different channel access capabilities of secondary users

Abstract

Cognitive radio technology deals with the problem of spectrum scarcity. Such technology allows the secondary users (SUs) to access the primary users’s (PUs) channels without causing harmful interference to the PU’s transmission. In this paper, a novel multi-class SU cognitive radio model is introduced where each SU class has the ability to sense and operate on a subset of the network channels. Such multi-class SUs’ network could exist due to hardware limitations or network regulations. The model is analysed based on the mixed preemption/nonpreemption resume priority M/M/1 queueing model. First, the analysis is carried out assuming no priority between the SU classes. Next, a priority scheme is introduced to balance the performance between the different classes. The numerical results show the delay performance trade-off between the different classes and the overall delay enhancement to the network after prioritizing the classes. Moreover, comparative studies to related work in literature and simulation results for the effect of sensing errors on SU and PU networks are introduced. Based on these results, it is recommended to apply the priority-based model for low and medium PU’s loads when the system time is considered as a performance metric. As far as we know, the case of different channel access capabilities between the SUs has not been analysed in literature before.