Network architecture

Abstract

A telecommunications system is provided comprising a mobile device and an IP Multi-media Sub-system (IMS), the mobile device being connected to a Public Land Mobile Network (PLMN). The mobile device is adapted to: identify if the PLMN supports Customised Applications for Mobile network Enhanced Logic (CAMEL) and, upon receiving an attempt to initiate a call to a dialled number, if the PLMN supports CAMEL, allow the call to proceed. The PLMN is adapted to: receive a request to connect a call from the mobile device; invoke a CAMEL service trigger indicating that the call should be routed to the IMS; and, route the call to the IMS. The IMS is adapted to: control the call; and, refer the call to a call storage system for call storage. A mobile device, IP Multi-media Sub-system and method in a mobile device are also provided.

1 . A mobile telecommunications device configured to connect to a Public Land Mobile Network (PLMN), wherein the device is adapted to facilitate creation of a record of an original Short Message Service (SMS) message sent or received by the device, by:
 sending an IP data message corresponding to the original SMS message towards an SMS storage system, where the connected PLMN is a home PLMN and where IP data coverage is available, and,   sending a replica of the original SMS message towards the SMS storage system where the device is roaming or where IP data coverage is not available.   
     
     
         2 . A device according to  claim 1 , in which, if an origination or destination of the SMS matches one of a predetermined list of originations or destinations stored on the mobile device, the device does not store the SMS. 
     
     
         3 . A device according to  claim 1 , in which the device is further adapted to:
 identify if the connected PLMN supports Customised Applications for Mobile network Enhanced Logic (CAMEL); and,   upon detecting an attempt to initiate a call to a dialled number, if the connected PLMN does not support CAMEL, prevent the call from proceeding.   
     
     
         4 . A device according to  claim 1 , in which the device is further adapted to:
 identify if the connected PLMN supports Customised Applications for Mobile network Enhanced Logic (CAMEL); and   upon detecting an attempt to initiate a call to a dialled number, if the connected PLMN does not support CAMEL, the device is adapted to:
 send a data message to an IP Multi-media Sub-system (IMS), including the dialled number; 
 receive a pseudo-roaming number; and, 
 initiate a call to the pseudo-roaming number. 
   
     
     
         5 . A device according to  claim 4 , in which the data message is a session-based data message. 
     
     
         6 . A device according to  claim 5 , in which the data message is a Unstructured Supplementary Service Data (USSD) message. 
     
     
         7 . A device according to  claim 3 , in which the identifying if the connected PLMN supports CAMEL comprises evaluating the connected PLMN against a list of PLMNs that support CAMEL stored on the mobile device. 
     
     
         8 . A device according to  claim 7 , in which the mobile device is adapted to store the list upon receipt of the list from an IMS. 
     
     
         9 . A device according to  claim 3 , in which, if the dialled number matches one of a predetermined list of numbers stored on the mobile device, the mobile device is adapted to allow the call to proceed irrespective of whether the PLMN supports CAMEL. 
     
     
         10 . A method of creating a record of an original Short Message Service (SMS) message sent or received by a mobile device connected to a Public Land Mobile Network (PLMN), the method comprising:
 sending an IP data message corresponding to the original SMS message towards an SMS storage system, where the connected PLMN is a home PLMN and where IP data coverage is available, and,   sending a replica of the original SMS message towards the SMS storage system where the device is roaming or where IP data coverage is not available.   
     
     
         11 . A method according to  claim 10 , wherein an SMS distribution server receives the replica SMS message, and the method further includes:
 the SMS distribution server normalising the replica SMS message into an SMS message exactly corresponding to the original SMS message and then sending the normalised SMS message to the SMS storage system.   
     
     
         12 . A method according to  claim 10 , in which, if an origination or destination of the SMS matches one of a predetermined list of originations or destinations stored on the mobile device, not storing the SMS. 
     
     
         13 . A method according to  claim 10 , further comprising:
 identifying if the connected PLMN supports Customised Applications for Mobile network Enhanced Logic (CAMEL); and,   upon detecting an attempt to initiate a call to a dialled number, if the connected PLMN does not support CAMEL, preventing the call from proceeding.   
     
     
         14 . A method according to  claim 10 , further comprising:
 identifying if the connected PLMN supports Customised Applications for Mobile network Enhanced Logic (CAMEL); and,   upon detecting an attempt to initiate a call to a dialled number, if the connected PLMN does not support CAMEL:
 sending a data message to an IP Multi-media Sub-system (IMS), 
   including the dialled number;
 receiving a pseudo-roaming number; and, 
 initiating a call to the pseudo-roaming number. 
   
     
     
         15 . A method according to  claim 14 , in which the data message is a session-based data message. 
     
     
         16 . A method according to  claim 13 , in which the data message is an Unstructured Supplementary Service Data (USSD) message. 
     
     
         17 . A method according to  claim 12 , in which the identifying if the connected PLMN supports CAMEL comprises evaluating the connected PLMN against a list of PLMNs that support CAMEL stored on the mobile device. 
     
     
         18 . A method according to  claim 17 , further comprising storing the list upon receipt of the list from an IMS. 
     
     
         19 . A method according to  claim 12 , further comprising, if the dialled number matches one of a predetermined list of numbers stored on the mobile device, allowing the call to proceed irrespective of whether the PLMN supports CAMEL. 
     
     
         20 . A computer readable medium comprising instructions which when executed by a processor of a mobile device being connected to a Public Land Mobile Network (PLMN), cause the mobile device to carry out the method of  claim 10 .