Review of Spectrum Handoff Schemes in Cognitive Radio Networks

Cognitive radio networks (CRN) are a new technology that offers a promising solution to the problem of spectrum scarcity. To ensure optimal spectrum utilization, when the primary user (PU) is detected to be present on the channel or there is a decrease in spectrum quality, the secondary user (SU) must switch or remain on the channel, this condition is known as spectrum mobility. One of the problems related to spectrum mobility is spectrum handoff, where this handoff plays an important role in supporting the availability and performance of spectrum mobility. This paper presents various schematic handoff modeling techniques for secondary users in performing spectrum handoffs. Apart from channel efficiency, minimizing the number of handoffs is also a challenge. In the future, it is necessary to strive for a handoff algorithm that can adapt to these conditions.