Method for performing initial ranging in cognitive radio network and system thereof

The initial ranging perform a method and system are disclosed in the cognitive radio network. Performing ranging method in that the radio network in accordance with one embodiment of the present invention includes the steps of detecting a signal received on the one or more ranging interval; Estimating a first time offset on the basis of the correlation between the sub-carrier index of the signal detected from the one or more ranging interval relationship; Wherein estimating the one or more second time offset based on the correlation of the signals with a plurality of pre-determined codes detected by the ranging interval, and detects the initial ranging code of the plurality of codes; And characterized in that it comprises the step of estimating a time offset of the terminal that performs the initial ranging (initial ranging) to the initial ranging code, the detected using the first time offset and the second time offset the estimated It shall be.