Patent ID: 8532057

Claim:
A method of supporting handover, the method performed by a mobile station (MS) and comprising: transmitting a handover request message to a serving base station (SBS); receiving a handover response message, which includes handover related information and authentication information, from the SBS, wherein the authentication information is generated based on an authentication key (AK) of the MS, a CMAC (Cipher-based Message Authentication Code) key count of the MS, and a dedicated code index (DCI), and the authentication information is generated by a target base station (TBS); deriving the DCI based on the AK, the CMAC key and the authentication information; obtaining a dedicated code index (DCI) indicating a dedicated ranging code indicated by the DCI; transmitting the dedicated ranging code to the TBS for performing a non-contention based ranging; and receiving a ranging response message from the TBS in response to the dedicated ranging code.