Date Added: Jan 2013
With the rapid increase in the number of wireless enabled devices, contention for wireless spectrum has never been higher. Cognitive radios have been seen as the way to minimize the congestion by allowing multiplexing between primary users of a piece of spectrum with other opportunistic secondary users of the same spectrum. This allows each radio to look out for less congested spectrum to move to and possibly improve its communication performance. The Cognitive Radio (CR) technique has mainly dealt with how spectrum can be sensed, the co-existence of primary and secondary users, and the channel access aspect.