16 Compatibility of USAT ME’s and applications

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

16.1 USAT Classification

Given the wide ranging hardware capabilities of UICCs and MEs, together with the development of USAT applications and applets, a USAT classification shall be supported to determine their respective capability and compatibility. The USAT classification shall apply both to UICCs, MEs and applications and applets.

The objective is to:-

– classify the requirements of a USAT UICC/applications and

– identify the commands and features supported by the ME

The development and maintenance of the USAT specification is done in accordance to the ETSI/3GPP release procedures. . I.e. annual releases of the specifications are done providing support for new commands and enhancements of existing commands. The annual Release may both contain commands that are mandatory for that Release and commands that are optional.

The classification of the optional commands and features in a given Release may be done with the concept of “Letter Classes”. A Letter Class identifies a subset of functionality of the Release, which will provide the user, USAT serving environment and application writer with a consistent set of commands and features.

The concept of a USAT Letter Classes is introduced to help identify the ME, and the UICC /USAT application compatibility within a given Release. The USAT Letter Class is distinct and unrelated to the existing PLMN UE Classmark. The USAT Letter Classes are not used during capability negotiations, but are intended to assist in designing applications by provision of a means for an application designer to identify which combinations of USAT features are supported by the MEs. Capability negotiations between the UICC and the ME are performed at the feature level, independent of the USAT Letter Class.

In addition to classifying the ME as conforming to a specific Release and if applicable one or several Letter Classes within the release, an ME manufacturers declaration shall be provided. This shall indicate in detail the commands and features supported by the ME. Any conformance testing shall be performed in accordance to this declaration.

The support of a given Letter Class doesn’t require the support of another Letter Class.

USAT applications will be developed to execute on USAT UE´s in one or more classifications. In order for USAT applications to be properly supported by a USAT UE, the application shall be designated by the same classification of USAT UE’s on which they are intended to be executed.

16.2 ME/USIM operation

In the case of an ME not supporting SAT/USAT or not supporting a certain SAT/USAT feature the following shall apply:

– the USIM shall control (i.e. allow or prevent) the access to the network.
This allows the USIM to prevent the use of a subscription (which may rely on the support of USAT features for correct operation) in an uncontrolled manner.

– if access to a PLMN is not prevented the ME shall support the non-USAT PLMN features without restriction.

16.3 ME/UICC capability information exchange

If supported, the UICC and the ME shall exchange USAT capabilities when the card session is initiated.

This exchange of information is important since the UICC then knows what the ME is capable of, and the UICC can thus adapt the service made available to the user accordingly. If the UICC does not receive any ME capability information it shall assume that the ME does not support USAT.

A UICC that supports USAT shall not attempt to invoke USAT functions in the ME if the ME has not indicated USAT support.

An ME that supports USAT shall not attempt to invoke USAT functions in the UICC if the UICC has not indicated that USAT is supported and is active.

16.4 ME and compatibility

For compatibility testing the ME manufacturers shall provide a declaration of the Release and if applicable the Letter Class(es) supported by the ME including the detail of all commands and features supported by the ME. It can be envisaged that ME implementations will exist that are compliant to a given release and which support commands and features from later releases.

16.5 Void