Characterizing reliability in cognitive radio networks

Future wireless communications will require an increasing opportunistic use of the licensed radio frequency spectrum. The cognitive radio (CR) paradigm provides a suitable framework for this purpose. However, the phenomena of channel fading and primary cum secondary interference in cognitive radio networks does not guarantee application demands to be achieved continuously over time. In this paper, we consider the problem of analytically evaluating the reliability of a general multi-hop, multi-channel, multi-radio, multi-rate cognitive radio network, serving a given multi-application demand vector. We define reliability as the probability that a given demand vector is achieved. Each element in the vector is the desired flow rate of an application. We give a detailed simulation study to support our theory, and analyze the effect of the number of channels, radios, and simultaneous flows on the reliability of a CR network. Our quantitative measure of reliability is indicative of the effectiveness of a CR network, and will help network engineers to tune the network for better performance.