| 摘要 |
<p>A technique for the handover of a mobile station (30, 31, 44, 45) between base stations (32, 33, 39, 40) in a radio communications system in which the mobile stations and base stations each derive an encryption key (DCK) for encrypting their communications to each other. On handover, the key derivation parameters used by a mobile station to derive the encryption key are passed to the new base station, which then uses the parameters to re-derive the encryption key. The mobile station can then communicate with the new base station using the original encryption key for that call. Preferably the new base station seeks the key derivation parameters for a particular mobile station from a database. The key derivation parameters passed to the new base station on handover preferably comprise only parameters previously transmitted over the air-interface. In this way handover of a mobile station between base stations is achieved, without passing of the air-interface encryption key over the air-interface.</p> |
