Antenna Systems and Propagation for Cognitive Radio

Cognitive radio systems are quickly reshaping the future of wireless communications, sensing, and data sharing. Wireless data traffic is projected to double every year and this will impact spectrum availability in all sectors of our society. Various research communities, however, have differing definitions of cognitive radio (CR) and each community has unique views as the defining features of CR. Communication theorists view CR as primarily about dynamic spectrum sharing, while networking/IT researchers interpret CR as a device capable of cross-layer optimization. Computer scientists picture CR as a device capable of learning and adapting, with assumed capabilities, while the hardware/ RF community often views it as an evolutionary step from Software Defined Radio. Amid all of these conceptions of cognitive radio, the possibilities for antenna systems and related propagation issues to play more active role in system-level performance are often lost.