1. A method for categorizing a candidate signal as one of an incumbent signal and not an incumbent signal, the candidate signal having been detected on a candidate frequency channel by at least one node of a wireless regional area network (“WRAN”) of cognitive radios, the method comprising: each of a plurality of nodes in the WRAN sensing its surrounding frequency environment; each of the plurality of nodes preparing a sensing report at least reporting if the candidate signal has been detected; each of the plurality of nodes conveying its sensing report to a signal authenticator; and the signal authenticator categorizing the detected candidate signal as one of a valid incumbent and not a valid incumbent, the categorizing being according to an evaluation of the sensing reports that includes a synthesis of information from at least two of the sensing reports.