Method of handover
A method for quickly performing a handover in a wireless access system is disclosed. The method for quickly performing a handover includes transmitting a handover request message to a serving base station (SBS), receiving a handover response message from the serving base station (SBS), and transmitting an uplink sequence generated by authentication-associated information of the serving base station (SBS) to a target base station (TBS). Therefore, a mobile station (MS) can complete the handover without exchanging a ranging message with the target base station (TBS), such that a communication interruption time can be minimized.
1. A method for quickly performing a handover at a mobile station, the method comprising:
performing an authentication process during a registration with a serving base station (SBS), wherein an authentication key is at least received or transmitted by the mobile station during the registration with the SBS;
transmitting a handover request message to the SBS;
receiving a handover response message including a dedicated handover ranging sequence index from the SBS, wherein the dedicated handover ranging sequence index is encrypted by the authentication key and a cipher-based message authentication code (CMAC)-key count;
generating a dedicated handover ranging code corresponding to the dedicated handover ranging sequence index; and
transmitting the dedicated handover ranging code to a target base station (TBS) as a first time transmission for the TBS.
2. The method according to claim 1 , wherein the dedicated handover ranging code is generated when the authentication key is used as a seed of a pseudo random bit sequence (PRBS) generator.
3. The method according to claim 1 , further comprising:
receiving information indicating whether or not the dedicated handover ranging code is supported prior to transmitting the handover request message.
4. The method according to claim 1 , further comprising:
receiving uplink resources or downlink data from the TBS; and
performing authentication for mutually authenticating with the TBS using the uplink resources or the downlink data.
5. The method according to claim 1 , wherein the handover response message includes connection update information of the TBS and information of an action time at which a handover to the TBS is performed.
6. The method according to claim 5 , wherein the connection update information includes at least a basic connection identifier (BCID) for use by the TBS, a primary connection identifier (PCID) for use by the TBS, or a transport connection identifier (TCID) for use by the TBS.
7. The method according to claim 1 , wherein a least significant bit (LSB) of the authentication key (AK) is used when the dedicated handover ranging code is generated.