QoS-aware Spectrum Sensing in White-Fi Cognitive Radio Networks

With the massive and growing number of wireless devices, the scarcity of the available frequency spectrum is a serious concern. The QoS requirements of most contemporary networking applications exacerbate this issue. Through opportunistic utilization of the available frequency spectrum, Cognitive Radio (CR) technology can offer some appropriate solutions to this problem. Unlicensed spectrum is shared very efficiently by Wi-Fi devices. To improve the availability of frequency spectrum and their efficient use, integration of CR and Wi-Fi technologies appear to be a promising approach. This combination forms the so-called White-Fi. This paper discusses the relevant spectrum assignment and sensing issues in White-Fi implementations. We also report the results of our simulation studies on the effects of sensing variations in the QoS levels of several typical applications. These studies show the effects of an intelligent sensing strategy that is aware of the application requirements on White-Fi QoS. Based on those, we propose some sensing improvements that may mitigate such effects on QoS. Our works indicate that while such an approach can result in a more efficient use of the available spectrum, the burden of sensing and the inevitable delays may result in some QoS degradations.