Mobile Subscriber Roaming n Different Mobile Networks Using UIM and PASM

During a time when cellular systems are being deployed in massive scale worldwide, international roaming is becoming increasingly important. This paper presents UIM (User Identification Module) for mobility support, authentication, and service portability between different mobile systems. We also introduce network model based on PASM(Portable Authentication and Mobility Service Machine) which will support signaling protocol and user information conversions with database for roaming between different mobile networks. Stored data types and elements in UIM, logical data structure and configuration, and registration procedures are described here in the case of DCN (Digital CDMA (Code Division Multiple Access) Network System) and GSM (Global System for Mobile Communications).