Identity management for mobile devices

1. A method of managing identities for use in a mobile telecommunications device in a telecommunications network, the method comprising:

triggering an identity management process based on a decision trigger detected by a Subscriber Identity Module (SIM);

detecting one or more parameters of a set of parameters of a currently available mobile telecommunications network;

identifying the decision trigger from a set of decision triggers; said set of decision triggers comprising changes to the contents of configuration files in the SIM and commands received via the mobile telecommunications device by the SIM; wherein the identity of each of the decision triggers in the set defines a specific corresponding identity management process to be implemented;

determining a network identifier by the identity management process determined by the identified decision trigger and by the detected one or more parameters of the mobile telecommunications network; and

selecting a selected identity in accordance with the network identifier determined and modifying an active identity of the mobile telecommunications device to be the selected identity when the active identity is not already the selected identity; wherein selecting the selected identity comprises searching an identity database comprising one or more entries of Mobile Country Codes to find the entry of a Mobile Country Code in the identity database that corresponds to a Mobile Country Code of the network identifier determined and selecting an International Mobile Subscriber Identity of the entry.

2. The method as claimed in claim 1 , wherein each identity comprises an International Mobile Subscriber Identity IMSI and said one or more parameters of the mobile telecommunications network comprise a Mobile Country Code and a Mobile Network Code.

3. The method as claimed in claim 2 , wherein selecting the International Mobile Subscriber Identity IMSI comprises searching through an ordered list in the identity database to find the entry in which the Mobile Country Code and Mobile Network Code in the identity database match the Mobile Country Code and Mobile Network Code of the network identifier determined, and selecting the International Mobile Subscriber Identity of the entry.

4. The method as claimed in claim 3 , wherein selecting the International Mobile Subscriber Identity further comprises, if there is no entry in the identity database for which the Mobile Country Code and the Mobile Network Code match the Mobile Country Code and Mobile Network Code of the network identifier determined, selecting a first entry in which the Mobile Country Code matches the Mobile Country Code of the network identifier determined, and selecting the International Mobile Subscriber Identity of the first entry.

5. The method as claimed in claim 4 , wherein selecting the International Mobile Subscriber Identity further comprises, if there is no entry in the identity database for which the Mobile Country Code matches the Mobile Country Code of the network identifier determined, selecting a default International Mobile Subscriber Identity.

6. The method as claimed in claim 1 wherein when the identified decision trigger is a command received by the SIM, the identity management process includes the step of submitting a further request for one or more parameters of the set of parameters of the currently available mobile telecommunications network.

7. A subscriber identity module for use in a mobile telecommunications device and having a plurality of identities for use in a mobile telecommunications network, the subscriber identity module (SIM) comprising a memory and a processor, wherein the memory comprises an identity management process for execution by the processor and an identity database, wherein the processor is adapted to:

trigger an identity management process based on a decision trigger detected by the SIM;

detecting one or more parameters of a currently available mobile telecommunications network;

identifying the decision trigger from a set of decision triggers; said set of decision triggers comprising of changes to the contents of configuration files in the SIM and commands received via the mobile telecommunications device by the SIM; wherein the identity of each of the decision triggers in the set defines a specific corresponding identity management process to be implemented;

determining a network identifier by a process determined by the identified decision trigger and by the detected one or more parameters of the mobile telecommunications network; and

selecting a selected identity in accordance with the determined network identifier and modify an active identity of the mobile telecommunications device to be the selected identity when the active identity is not already the selected identity, wherein selecting an identity comprises searching an identity database comprising one or more entries of Mobile Country Codes to find the entry of a Mobile Country Code in the identity database that corresponds to a Mobile Country Code of the network identifier determined, and selecting an International Mobile Subscriber Identity of the entry.

8. The subscriber identity module as claimed in claim 7 , wherein each identity comprises an International Mobile Subscriber Identity and said one or more parameters of a mobile telecommunications network comprise as Country Code and Mobile Network Code.

9. The subscriber identity module as claimed in claim 8 wherein the memory comprises the identity database, and wherein each record in the identity database comprises an International Mobile Subscriber Identity and Mobile Country Code and a Mobile Network Code for that International Mobile Subscriber Identity.

10. The subscriber identity module as claimed in claim 9 , wherein the identity database comprises a plurality of records with the same Mobile Country Code.