METHOD AND APPARATUS FOR TRANSMITTING DATA IN WIRELESS COMMUNICATION SYSTEM

The present invention relates to a method and apparatus for transmitting data in a mobile communication system and, more particularly, to a method and apparatus for transmitting data by a base station in an unlicensed frequency. To achieve the above described problem, a method for transmitting data by a base station in a wireless communication system according to an embodiment of the present invention may comprise the steps of: transmitting a first signal for determining whether a data transmission is possible in an unlicensed frequency band; transmitting a second signal for reserving a data transmission in the unlicensed frequency band when the data transmission in the unlicensed frequency band is possible; and transmitting first data to a terminal through the unlicensed frequency band after transmitting the second signal. According to an embodiment of the present invention, a base station determines whether other communication devices do not use the unlicensed frequency band, and transmits a channel reservation signal having a period shorter than a resource allocation period during a predetermined period of time, thereby pursuing coexistence with other communication devices and improving the performance of a communication system at the same time.