The paper describes spectrum sensing using single-radio switched-beam arrays with reactance-loaded parasitic elements. At a given frequency, the antenna's loading conditions (reactive loads) are optimized for maximum average beamforming gain in the beampattern look direction. Circular permutations of the reactive loads rotate the narrowband beampattern to different angular positions dividing the whole space around the cognitive receiver into several angular subspaces. The beampattern directionality leverages the performance of spectrum sensing algorithms like the energy detection by enhancing the receive signal-to-noise ratio. Moreover, the selection combining across the weakly correlated beampatterns gives rise to a diversity action further boosting the probability of detection.
Proceedings of the 2012 7th International Icst Conference on Cognitive Radio Oriented Wireless Networks and Communications: Crowncom 2012, 2012, p. 118-123
7th International ICST Conference on Cognitive Radio Oriented Wireless Networks and Communications (CrownCom), 2012