1. Federal Communications Commission, , Spectrum Policy Task Force Report, ET Docket No. 02-135, Nov. 2002.
2. Wellens, M., J. Wu, and P. Mähönen, "Evaluation of spectrum occupancy in indoor and outdoor scenario in the context of cognitive radio," Proc. 2nd Intl. Conf. on Cognitive Radio Oriented Wireless Networks and Commun., 420-427, Aug. 2007.
doi:10.1109/98.788210
3. Mitola, III, J., G. Q. Maguire, and Jr., "Cognitive radio: Making software radios more personal," IEEE Pers. Commun., Vol. 6, No. 4, 13-18, Aug. 1999.
doi:10.1109/JSAC.2004.839380
4. Haykin, S., "Cognitive radio: Brain-empowered wireless communications," IEEE J. Sel. Areas in Commun., Vol. 23, No. 2, 201-220, Feb. 2005.
doi:10.1109/JSEN.2010.2058097
5. Sharma, R. K. and J. W. Wallace, "Correlation-based sensing for cognitive radio networks: Bounds and experimental assessment," IEEE Sensors J., Vol. 11, No. 3, 657-666, Mar. 2011.
6. Urkowitz, H., "Energy detection of unknown deterministic signals," Proc. IEEE, Vol. 55, No. 4, 523-531, Apr. 1967.
doi:10.1109/SURV.2009.090109
7. Yucek, T. and H. Arslan, "A survey of spectrum sensing algorithms for cognitive radio applications," IEEE Communications Surveys and Tutorials, Vol. 11, No. 1, 116-130, First Quarter 2009.
8. Hall, P. S., P. Gardner, and J. Kelly, "Reconfigurable antenna challenges for future radio systems," Proc. 3rd Intl. Conf. on Antennas and Propag., 949-955, Mar. 2009.
doi:10.1049/el.2009.0935
9. Ghanem, F., P. S. Hall, and J. R. Kelly, "Two port frequency reconfigurable antenna for cognitive radios," Electronics Letters, Vol. 45, No. 11, 534-536, May 21, 2009.
10. Tawk, Y., J. Costantine, and C. G. Christodoulou, "A rotatable reconfigurable antenna for cognitive radio applications," IEEE Radio and Wireless Symposium (RWS), 158-161, Jan. 16-19, 2011.
11. Al-Husseini, M., A. El-Hajj, Y. Tawk, K. Y. Kabalan, and C. G. Christodoulou, "A simple dual-port antenna system for ognitive radio applications," 2010 International Conference on High Performance Computing and Simulation (HPCS), 549-552, Jun. 28-Jul. 2, 2010.
doi:10.1109/TAP.2011.2122293
12. Hamid, M. R., P. Gardner, P. S. Hall, and F. Ghanem, "Switched-band vivaldi antenna," IEEE Trans. Antennas Propag., Vol. 59, No. 5, 1472-1480, May 2011.
13. Zamudio, M. E., Y. Tawk, J. Costantine, S. E. Barbin, and C. G. Christodoulou, "Reconfigurable filter embedded into an antenna for UWB cognitive radio environment," Proc. IEEE --- APS Topical Conf. on Antennas and Propag. in Wireless Commun., 714-717, Sep. 2011.
doi:10.1109/JPROC.2012.2187140
14. Reed, J. H., J. T. Bernhard, and J. Park, "Spectrum access technologies: The Past, the present, and the future," Proc. IEEE, Vol. 100, 1676-1684, May 2012.
15. Nishimori, K., R. D. Taranto, H. Yomo, P. Popovski, Y. Takatori, R. Prasad, and S. Kubota, "Spatial opportunity for cognitive radio systems with heterogeneous path loss conditions," Proc. Vehicular Techn. Conf., 2631-2635, Apr. 2007.
doi:10.1109/TWC.2009.081541
16. Zhao, G., J. Ma, G. Y. Li, T. Wu, Y. Kwon, A. Soong, and C. Yang, "Spatial spectrum holes for cognitive radio with relay-assisted directional transmission," IEEE Trans. Wireless Commun., Vol. 8, No. 10, 5270-5279, Oct. 2009.
17. Taranto, R. D., K. Nishimori, P. Popovski, H. Yomo, Y. Takatori, R. Prasad, and S. Kubota, "Simple antenna pattern switching and interference-induced multi-hop transmissions for cognitive radio networks," Proc. IEEE 2nd Intl. Symposium on New Frontiers in Dynamic Spectrum Access Networks , 543-546, Apr. 2007.
doi:10.1049/ic:20080091
18. Mirkimali, A. and P. S. Hall, "Log periodic printed dipole array for wideband frequency reconfiguration," IET Seminar on Wideband, Multiband Antennas and Arrays for Civil or Defence Applications, 95-110, Mar. 2008.
doi:10.1049/el:19920954
19. Freeman, J. L., B. J. Lamberty, and G. S. Andrews, "Optoelectronically reconfigurable monopole antenna," Electronics Letters, Vol. 28, No. 16, 1502-1503, Jul. 1992.
doi:10.1109/TAP.2005.863398
20. Nikolaou, S., R. Bairavasubramanian, C. J. Lugo, I. Carrasquillo, D. C. Thompson, G. E. Ponchak, J. Papapolymerou, and M. M. Tentzeris, "Pattern and frequency reconfigurable annular slot antenna using PIN diodes," IEEE Trans. Antennas Propag., Vol. 54, No. 2, 439-448, Feb. 2006.
21. Krah, A., M. Grimm, N. Murtaza, W. Kotterman, M. Landmann, A. Heuberger, R. Thom, and M. Hein, "Over-the-air test strategy and testbed for cognitive radio nodes," 2011 XXXth URSI General Assembly and Scientific Symposium, 1-4, Aug. 13-20, 2011.
22. Murtaza, N., M. A. Hein, and E. Zameshaeva, "Reconfigurable decoupling and matching network for a cognitive antenna," Proc. of European Microwave Conference, 874-877, Oct. 2011.
doi:10.1109/LAWP.2011.2168937
23. Yong, C. and Y. J. Guo, "A frequency-agile compact array with a reconfigurable decoupling and matching network," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 1031-1034, 2011.
24. Murtaza, N., A. Krah, M. Grimm, A. Heuberger, R. Thoma, and M. Hein, "Multi-band direction-sensitive cognitive radio node," Proc. IEEE ---S Topical Conf. on Antennas and Propag. in Wireless Commun., 251-254, Sep. 2011.
25. Ettus Research, Online Available: http://www.ettus.com.
doi:10.1109/MVT.2012.2190219
26. Tandur, D., J. Duplicy, K. Arshad, D. Depierre, K. Moessner, J. Lehtomaki, K. Briggs, L. Goncalves, and A. Gameiro, "Cognitive radio systems evaluation: measurement, modeling, and emulation approach ," IEEE Vehicular Technology Magazine, Vol. 7, No. 2, 77-84, Jun. 2012.
27. Vodafone D2, Online Available: http://www.vodafone.de.
28. Winner II Spatial Channel Model, Online Available: http://www.ist-winner.org/phase-2-model.html .
29. Balanis, C. A., Antenna Theory: Analysis and Design, 3rd Ed., Wiley-Interscience, May 2005.
30. Belfiori, F., S. Monni, W. V. Rossum, and P. Hoogeboom, "Side-lobe suppression techniques for a uniform circular array," Proc. 7th European Radar Conf., 113-116, Sep. 2010.