Method and apparatus for managing hyper frame number for ciphering/deciphering in mobile communication system

摘要

A method and an apparatus for managing an HFN for ciphering/deciphering at an RNC of a mobile communication system are provided. In the method, a Timing Adjustment (ToA) value is received from a base station, and a Connection Frame Number (CFN) is corrected. Whether correction of the CFN has been generated within the same cycle is determined by comparing the correction CFN with an absolute CFN serving as a reference. An HFN value is changed or maintained depending on whether the CFN correction has been generated within the same cycle.