A Case Study of QoS Provisioning in TV-Band Cognitive Radio Networks

Dynamic Spectrum Access (DSA) MAC protocols allow a Cognitive Radio (CR) device to opportunistically access unused or less crowded spectrum while ensuring protection for the incumbents. Though DSA shows great potential to enhance spectrum efficiency, the associated constraints on 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 are subject to additional interference and interruption from incumbents. In this paper, we present a case-study of key QoS provisioning techniques in DSA protocol design that facilitate the required application QoS. Specifically, we consider a 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 (referred as QPDP) through extensive simulations. The results show the effectiveness of DSA coupled with QoS provisioning, in supporting QoS-demanding consumer- oriented network applications in TV bands. This outcome is significant as FCC has recently approved UHF bands for unlicensed operations in the second Report and Order in the USA, and various DSA-based personal/portable CR systems are being actively considered by the consumer wireless industry.