System and method of passing encryption keys after inter-exchange handoff

摘要

A system and method in a radio telecommunications network of passing a mobile station's encryption keys from an anchor Mobile Switching Center (MSC (11)) to a serving MSC (12) after the mobile station (MS (14)) has been handed off (25) from the anchor MSC to the serving MSC. If the need arises to perform an inter-system handoff of the MS before the encryption keys are sent from the Home Location Register/Authentication Center (HLR/AC (17)) to the anchor MSC, the MS may be handed off, and the invention enables the keys to be forwarded to the serving MSC. The anchor MSC modifies an ANSI-41 Information Forward (INFOFWD(27)) Invoke message to carry the encryption keys, and sends the message from the anchor MSC to the serving MSC. The message also includes a Confidentiality Modes (Desired) parameter. The serving MSC sends an activation order (28) to the MS to activate the confidentiality modes desired, and then sends an INFOFWD Return Result message (30) to the anchor MSC reporting the confidentiality modes that were actually activated.