International Journal of Engineering Sciences & Research Technology (IJESRT)
As wireless communication increases day-by-day the available spectrum becomes scarcer as the demand for spectrum usage increasing day-by-day for all wireless applications. The major cause is significant amount of the spectrum leads to underutilization. To mitigate this problem effective utilization of spectrum is must. For this Cognitive Radio (CR) was introduced. Cognitive radio enables secondary users to sense which portions of the spectrum are available, select best available channel, coordinate spectrum access with other users and vacate the channel when a primary user reappears for spectrum usage rights.