4 Description

(U)SIM Application Toolkit (USAT)22.0383GPPRelease 17Service descriptionStage 1TS

USAT provides a standardised execution environment for applications stored on the UICCand the ability to utilize certain functions of the supporting mobile equipment. USAT provides mechanisms which allow applications, existing in theUICC, to interact and operate with any ME which supports the specified mechanism(s) thus ensuring interoperability between a UICC and an ME, independent of the respective manufacturers and operators. A transport mechanism is provided enabling applications to be down-loaded and/or updated.

A significant aspect of USAT is the highly secure environment provided by the UICC. This is further enhanced by the fact that the subscriber and the issuer of the UICC and also the USAT applications have a "trusted relationship" (e.g. the subscriber trusts the issuer of the UICC to charge correctly for the resources used). This allows certain features, such as call control, to be implemented with a degree of freedom which would not be acceptable in a "non-trusted relationship".

The introduction of the USAT execution environment into UEs (i.e. ME+USIM) is a significant step forward in their evolution. The ability of UEs to support USAT represents an extension of the UE’s and PLMN capabilities. In order to allow current and future technologies to exploit and benefit from this, a standardized means of exchanging the MEs’ and USIMs capability profiles is supported.

This Technical Specification defines an enhancement of the USIM/ME interface.