A Survey on Spectrum Handoff Algorithm for Continuous Connectivity

Cognitive Radio networks (CR) is a new technique that uses available unlicensed spectrum band this is due to the limited number of fixed licensed spectrum bands [1]. The main features of the CR are spectrum sensing, management, sharing, and mobility [2]. This paper focuses on spectrum mobility for military systems often referred to as spectrum handoff for military systems, which is a process when the CR user changes its frequency of operation due to spectrum occupancy by the licensed user. Spectrum mobility is important in military networks since mission success may depend on reliable communications. In this paper, we propose the use of Fuzzy logic to come up with a decision making handoff scheme. The proposed scheme avoids interruptions caused by the movement of a secondary user and minimizes handoff latency if the SU selects a correct channel. It was observed through the analysis of literature that even though most of the existing schemes can perform handoff successfully, these existing schemes result in slow handoff and are complicated to implement.