Patent ID: 8660088

Claim:
A method in a serving Radio Network Controller, SRNC, for controlling inter RAT handover to E-UTRAN of a User Equipment, UE, with E-UTRA capability operating in a serving network comprising said SRNC, wherein the SRNC receives, from a Serving GPRS Support Node, SGSN, security keys generated at authentication and key agreement, AKA, upon attachment of the UE to the serving network; comprising the steps of: determining which type of UICC (Universal Integrated Circuit Card) the UE is equipped with by analyzing the security keys received from SGSN; and using the knowledge of which type of UICC the UE is equipped with to base a decision on whether to allow handover of the UE to E-UTRAN, wherein the Inter RAT handover is a handover from UTRAN to E-UTRAN, wherein security keys defined for UTRA access, generated by a UICC of type USIM, are a ciphering key (CK) of 128 bits and an integrity protection key (IK) of 128 bits, whereby a ciphering key (Kc) generated by a UICC of type SIM may be converted to said security keys defined for UTRA access by the following conversion functions: CK=Kc∥Kc (equation c4) IK=Kc1xorKc2∥Kc∥Kc1xorKc2 (equation c5)