CORRELATION-BASED DETECTION IN A COGNITIVE RADIO SYSTEM

A user equipment senses a plurality of wireless signals it receives; estimates cyclic correlation of the received signals using a multi-variate sign function; determines from the estimated cyclic correlation which ones of the signals are detected based on cyclostationarity present at known cyclic frequencies; and a frequency resource is selected for opportunistic communications based on the frequencies over which were received the signals that were determined to be detected. In specific embodiments, the multi-variate sign function is bivariate; the detected signals are primary user signals and the selected frequency resource avoids frequencies on which they were received; and/or the detected signals are secondary user signals and the selected frequency resource can either avoid those frequencies on which they were received or use those frequencies for the UE's own opportunistic communications.