In a wireless communication system, when a transmission node has data to be transmitted to a reception node, it checks an acknowledgement slot of the current communication frame and transmits information regarding a reception available acknowledgement slot to the reception node through a request-to-send (RTS) slot in the current communication frame, and the reception node transmits information regarding the data slot available for receiving among at least one data slot corresponding to the reception available acknowledgement slot to the transmission node through a clear-to-send (CTS) slot corresponding to the data request slot in the current communication frame. Thereafter, the transmission node transmits data to the reception node through a reservation data slot of the subsequent communication frame until the message transmission fails or finishes.