In a first time interval Tl a first frequency band FB is pseudorandomly selected from a designated spectrum, and a first analysis result is determined by sensing the first FB during the first Tl and then transmitted. In a second Tl a second FB is pseudorandomly selected from the designated spectrum, and a second analysis result is determined by sensing the second FB during the second Tl and then transmitted. Where multiple devices do this the entire spectrum is sensed, each band by a subset of devices that changes at each Tl, and so any unused or underutilized spectrum is searched by the collaborative spectrum sensing, which avoids propagation problems such as fading. Also, a central node can assure various collaborating users report different FBs in different TIs such that the subset of reporting users changes for at least one of the bands in each subsequent reporting Tl. Sensing and communication can be performed in different portions of the same network defined transmission time interval.