Abstract: The invention relates to a method for authenticating a radio communication network vis-à-vis a mobile station. In such a method, batches of authentication vectors that each contain an authentication token with a pertaining sequence number are generated on the network side. At the mobile station side an identity module of the mobile station decides whether a sequence number contained in a previously selected authentication vector is accepted for authentication or rejected. The identity module is informed by the radio communication network which authentication tokens with the pertaining sequence numbers are present in the same batch. One sequence number per batch is stored by the identity module and is used to decide whether the sequence number received is accepted or rejected.

Abstract: According to the inventive method, a message is transmitted from an operating mobile radio network (NW2) to a terminal (MS1a) that identifies coding techniques (UEA-NW) supported by the operating mobile radio network in order to establish a connection between the terminal (MS1a) that supports a number (UEA-MS) of coding techniques and the operating mobile radio network (NW2). The terminal selects, if available, a coding technique (UEA) that is supported by the terminal and the operating mobile radio network (NW2), and the connection is operated using the coding technique selected by the terminal. If no coding technique is available that is supported by the terminal and the operating mobile radio network, the connection is operated uncoded only upon prior authorization.

Abstract: According to the inventive method, a message is transmitted from an operating mobile radio network (NW2) to a terminal (MS1a) that identifies coding techniques (UEA-NW) supported by the operating mobile radio network in order to establish a connection between the terminal (MS1a) that supports a number (UEA-MS) of coding techniques and the operating mobile radio network (NW2). The terminal selects, if available, a coding technique (UEA) that is supported by the terminal and the operating mobile radio network (NW2), and the connection is operated using the coding technique selected by the terminal. If no coding technique is available that is supported by the terminal and the operating mobile radio network, the connection is operated uncoded only upon prior authorization.

Abstract: The interoperation between UMTS and GSM in the handover context includes the following method steps. An authentication vector is first generated by the UMTS HLR/AuC and various UMTS authentication parameters (XRES, CK, IK and AUTN) are derived. The authentication vector is distributed, depending on the type of VLR that requests authentication vectors, whether it is a UMTS VLR or a GSM VLR. The UMTS user is authenticated either in UTRAN or in GSM BSS. When a UMTS user is attached through a UTRAN, the controlling VLR initiates UMTS authentication and key agreement. When a UMTS user is attached through a GSM BSS, the controlling VLR initiates GSM authentication and key agreement. This is done using a UMTS authentication vector or a GSM authentication vector, depending on the type of VLR controlling the GSM BSS. The user is then handed over from one system to the other.