Fuzzy Logic Based Spectrum Handover Approach in Cognitive Radio Network: A Survey

The demand of wireless application is increasing day by day but there is crunch in availability of spectrum band as spectrum bands are in limited amount. Cognitive Radio Network (CRN) is an advanced technique that utilize licensed spectrum bands that are available. Cognitive function cycle has mainly four functions such as, sensing of spectrum, spectrum decision, sharing of spectrum and spectrum mobility. Here the emphasis is on spectrum handover which is performed when licensed user returns to its channel or if channel condition become worst then SU will have to vacate the channel for the primary users having higher priority. In this survey paper, the utility of fuzzy logic in spectrum handover is discussed. Furthermore, the spectrum handover techniques using fuzzy logic in cognitive radio network have been discussed such as; spectrum handover based on fuzzy logic controller, spectrum handover based on power control, channel reservation based spectrum handover, spectrum handover based on underlay power sharing, hierarchical FLS based handover, handover decision based on SU priority, spectrum handover based on negotiation approach are described briefly. The decision making is the main challenge for CRN, so concept of fuzzy logic is introduced in spectrum handover for efficient decision making to reduce handover delay, optimizing power consumption, unwanted handover is reduced.