  Today's wireless networks are characterized by fixed spectrum assignment
policy. The limited available spectrum and the inefficiency in the spectrum
usage necessitate a new communication paradigm to exploit the existing wireless
spectrum opportunistically. Cognitive radio is a paradigm for wireless
communication in which either a network or a wireless node changes its
transmission or reception parameters to communicate efficiently avoiding
interference with licensed or unlicensed users. In this work, a fuzzy logic
based system for spectrum management is proposed where the radio can share
unused spectrum depending on some parameters like distance, signal strength,
node velocity and availability of unused spectrum. The system is simulated and
is found to give satisfactory results.
