Interference Analysis of TV-Band Whitespace

Cognitive radio (CR) has been suggested as a method for promoting more efficient spectrum usage through the principles of spectrum sensing and dynamic spectrum management. The IEEE 802.22 working group in particular is developing a wireless regional-area network (WRAN) standard that will employ unlicensed CR devices operating on a noninterfering basis in the commercial broadcast television (TV) bands. Before such TV-band CR networks can be deployed, the maximum levels of first adjacent and taboo channel interference that a digital television (DTV) receiver can tolerate must be determined. In this context, we will first provide an overview of the IEEE 802.22 WRAN system. Afterwards, we will report on an experimental study that was undertaken to characterize IEEE 802.22 WRAN interference limits into Advanced Television Systems Committee (ATSC) based DTV receivers. Lastly, we will discuss the implications of these WRAN interference limits in terms of the maximum allowable radiated power and out-of-band emission limits that are imposed on WRAN end-user devices.