Provided are methods and systems of using division-free duplexing (DFD) to reduce rendezvous time between two or more cognitive radio devices. The cognitive radio devices may opportunistically use available frequency spectra by communicating over available channels. To communicate, a first device may rendezvous with a second device by transmitting a beaconing signal over a frequency on which the second device is listening. DFD techniques may enable each of the devices to listen to a channel while concurrently transmitting beacon signals over the same channel. As periods of listening and periods of transmitting over the same channel need not be separated due to the transmitter cancelling approach used in DFD techniques, rendezvous time may be significantly reduced. Further, embodiments include a generalized DFD (GDFD) approach wherein devices listen to a broad band of frequencies, thus further reducing rendezvous time.