ABSTRACT
Spectrum maintenance or channel maintenance has been an integral part in modern communication systems. For instance, a seamless handoff from one channel to another is vital for a mobile user. In a broad sense, handoff in conventional systems is initiated when the user’s current channel deteriorates, and thus, it looks for a better one. In cognitive radio networks (CRNs), however, the concept is different due to the existence of two types of users, primary users (PUs) and seconday users (SUs). This has given rise to spectrum handoff where the SU initiates a handoff when the PU returns to one of the bands used by the SU. Thus, the spectrum handoff in CRNs depends on the behavior of PUs, and this is a major challenge, since such behavior is random in nature.
