Patent ID: 8649356

Claim:
A method for performing a presence check procedure carried out by a mobile station (MS) during handover in a broadband wireless access system, the method comprising: receiving a first signal for a presence check request from a serving base station (BS); transmitting a second signal to the serving BS in response to the presence check request; receiving a ranging acknowledgement (AAI_RNG-ACK) message indicating a ranging success status from the serving BS; and transmitting a ranging confirmation (AAI_RNG-CFM) message including an identifier (ID) of the MS to the serving B, wherein the first signal is received if the MS has failed a network reentry to a target BS after a lapse of a disconnect time indicating a time point at which the serving BS stops communication with the MS, wherein the first signal is an unsolicited ranging response (unsolicited AAI_RNG-RSP) message in which a specific bit required for requesting a ranging process from the MS is set, and wherein the second signal is a periodic ranging code.