Date Added: May 2012
To analyze scenarios like spectrum handoff in overlay cognitive radio networks, the authors need to capture the status change of the target channels in a more realistic manner. Most of the existing cognitive radio channel models assume target channels to be busy only when occupied by primary users. However, in reality the channel could be occupied by another secondary user in absence of a primary user and hence seen as busy by a secondary user that senses the channel. Actual busy channel consists of either a primary or other secondary user activity as observed by a potential incoming secondary user to the channel. Here, they present a channel model that captures a more realistic behavior of channel occupancy.