  Spectrum scarcity is one of the major challenges that the modern
communication engineers are going through because of inefficient utilization of
allocated frequency spectrum. The spectrum scarcity is a problem because there
is not enough wavelengths/frequency to match the number of channels which are
required to broadcast in a given bandwidth. Therefore, the utilization of
available allocated spectrum when licensed users are not in use offers an
opportunity as well as challenge, also, to increase the efficiency of spectrum
utilization. Cognitive Radio offers a promising solution by reutilisation of
unused allocated frequency spectrum. It helps to fulfil the demand of frequency
requirement for modern communication system to accommodate more data
transmission. In this optimum utilization of reuse of frequency spectrum
required optimising algorithms in all parts of Cognitive Cycle. This paper
focuses on designing a system based on fuzzy logic with a set of input and
output parameters to obtain an optimised solution. A comparative analysis is
also carried out among various types of membership functions of input and
output on Mamdani Fuzzy Inference System and Sugeno Fuzzy Inference System. The
proposed approach is applicable to design a better system model for a given set
of rules.
