INVITED PAPER

Cognitive Radio and Networking Research at Virginia Tech
A large research team with a wide range of expertiseVfrom ICs and reconfigurable computing to wireless networkingVworks to achieve the promise of cognitive radio.
By Allen B. MacKenzie, Senior Member IEEE , Jeffrey H. Reed, Fellow IEEE , Peter Athanas, Senior Member IEEE , Charles W. Bostian, Fellow IEEE , R. Michael Buehrer, Senior Member IEEE , Luiz A. DaSilva, Senior Member IEEE , Steven W. Ellingson, Senior Member IEEE , Y. Thomas Hou, Senior Member IEEE , Michael Hsiao, Senior Member IEEE , Jung-Min Park, Member IEEE , Cameron Patterson, Senior Member IEEE , Sanjay Raman, Senior Member IEEE , and Claudio R. C. M. da Silva, Member IEEE

ABSTRACT

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All of these techniques require radios to behave intelligently. In the case of secondary markets, radios must engage in negotiations with a spectrum broker to obtain access to spectrum appropriate to their needs. In a spectrum commons, radios must be aware of and respond to other users also using the commons. In the case of a secondary license, users must be alert for the appearance of primary users (PUs) as well as avoid other secondary users. Extraordinary progress has been made on applying cognitive techniques to obtain seamless adaptation of radio link parameters, opportunistic use of underutilized spectrum, and increased flexibility in modulation and waveform selection to better fit the current wireless environment. Increasingly, however, there is the realization that such intelligent radios, when placed in a network, might bring about unexpected and undesirable results unless network considerations are carefully explored. We have termed a network that intelligently takes end-to-end goals into account a cognitive network (CN) [7]. While this paper reflects the broad scope and interdisciplinary nature of the Wireless @ Virginia Tech efforts to address the challenging problems raised in the creation of CRs and CNs, it is not a complete catalog of our related work. In particular, we have omitted significant work on the use of