| 主权项 |
1. An apparatus for ciphering uplink data in a mobile communication system, the apparatus comprising:
a Radio Network Controller (RNC) for, when receiving a Radio Bearer Setup Complete after a ciphering activation time, determining a Hyper Frame Number (HFN) value of a User Equipment (UE) and changing an HFN value of the RNC to the determined HFN value of the UE, wherein, the changing of the HFN value of the RNC comprises determining, by the RNC, an HFN modification value and changing the HFN value of the RNC to the determined HFN value of the UE using the HFN modification value, wherein the RNC determines the HFN modification value by using a difference between an RNC Frame Number (RFN) corresponding to the ciphering activation time and an RFN corresponding to a movement time to a physical channel, and wherein the RNC determines the RFN of the ciphering activation time based on an RFN corresponding to when the Radio Bearer Setup Complete is received, a Connection Frame Number (CFN) of the ciphering activation time from the Radio Bearer Setup Complete, a CFN of when the Radio Bearer Setup Complete is received, and a predefined CFN range value. |
