Apparatus and method for adaptive transmission based on interference termperature cognition in the cognitive radio system

The present invention provides a method for ensuring an optimal transmission rate for a CR user while minimizing interference to a main user in a cognitive radio (CR) communication system. The CR user performs spectral idle detection at all times, selects a channel having the lowest interference temperature level, calculates a distance from the main user based on the interference temperature level measured at the CR user's receiver in a given channel environment , Calculates a transmission power of a CR user by performing a power control process, and performs adaptive modulation to obtain an optimal transmission rate performance by obtaining an interference signal power (SINR: Signal-to-Interference and Noiser Ratio) Determine the modulation scheme. Then, a signal is finally transmitted using the determined transmission power and modulation scheme. Cognitive Radio, Interference Temperature, Transmit Power Control, Adaptive Modulation, SINR