Hybrid cognitive radio communication system and method thereof

PURPOSE: A hybrid recognition radio communication system and method thereof are provided to reduce the burden of an interference channel by protecting a first user terminal from the interference of a second user terminal. CONSTITUTION: A determination unit(420) determines the usage state of frequency in a first user terminal. The first user terminal performs communication by preferentially using the frequency. If the determination unit determines the non-usage state of the frequency in the first user terminal, a control unit(430) changes an operation mode into an overlay mode. If the determination unit determines the usage state of the frequency in the first terminal, the control unit changes the operation mode into an underlay mode.