Performance study of a novel selective cooperative spectrum sensing scheme for secondary radios

In order to opportunistically utilize the licensed frequency band, secondary radios need to sense the spectrum for the presence of the primary radio. Non-cooperative and cooperative sensing schemes have been reported in the literature. In this paper, an improved spectrum sensing scheme, where cooperative sensing is performed only selectively according to a predefined criterion, is proposed. Our studies show that by introducing such intelligence between a pair of secondary radios, a significant improvement when performing primary radio detection can be achieved. We extend our study to the case when primary radio is a multiband (or multicarrier) system with multiple secondary radios each transmits through one subcarrier. A cross-band selective cooperation scheme, which takes the advantage that a radio can be the relay to multiple secondary radios, is proposed. Through analytical studies and simulations, we show that further improvement in primary user detection can be achieved.