Patent ID: 7609638

Claim:
A method of transmitting and receiving messages to initiate an idle mode of a mobile station in a wireless access system, the method comprising: at the mobile station, transmitting a de-registration request (DREG-REQ) message for requesting the idle mode initiation to a base station, setting a de-registration request retransmission count to a predetermined value and enabling a de-registration command standby timer, wherein the mobile station retransmits the de-registration request message to the base station when the de-registration command standby timer is expired before receiving a de-registration command (DREG-CMD) message from the base station and the de-registration request retransmission count is not exhausted; and at a base station, receiving the de-registration request message, transmitting the de-registration command message acknowledging the idle mode initiation to the mobile station and enabling a management resource holding timer, wherein the base station releases management resources with the mobile station when the management resource holding timer is expired.