摘要 |
<p>A security procedure for a Universal Mobile Telephone Service (UMTS) mobile communication system includes detecting a communication failure between a Radio Network Controller (RNC) which controls radio coverage within a prescribed geographical area and a Mobile Station (MS) in the geographic area, authenticating the MS and setting a new security parameter in response to the communication failure. The security parameter to be changed may be a ciphering key CK or an integrity key IK. Moreover, the steps of authenticating and setting a new security parameter may be performed separately or simultaneously.</p> |