Analysis of QoS Provisioning in Cognitive Radio Networks: A Case Study

Abstract

Dynamic Spectrum Access (DSA) is a promising solution to the problem of spectrum inefficiency. Based on Cognitive Radio (CR) technology, DSA allows a CR device to opportunistically access unused or less crowded spectrum while ensuring protection for the incumbents. Though DSA shows great potential to enhance network performance, its adverse side-effects on application QoS may limit its usefulness. QoS support in a DSA-based network is not trivial due to the fact that in addition to unfavorable characteristics of the wireless medium, the secondary devices must face additional interference and interruption from incumbents that have to be protected. In this paper, we present a case study of key DSA protocol characteristics necessary for QoS provisioning. Specifically, we consider a personal/portable CR system that supports high quality multimedia (including HDTV) streaming over UHF frequency bands. We model and evaluate the QoS-oriented CR system together with the underlying QoS-Provisioned DSA Protocol (called QPDP) through extensive simulations. The results show the effectiveness of the proposed DSA QoS provisioning approach in sustaining high levels of QoS, e.g., supporting HDTV streaming in TV bands. This outcome is significant as FCC has recently approved UHF bands for unlicensed operations in the USA, and various DSA-based CR systems are being actively designed by the wireless industry. The techniques outlined in this work can be generalized to be applicable to generic DSA design in various spectrum bands.