Mobile termination roaming forwarding for mobile devices
View Patent ↗A method for delivering a mobile terminated call to a mobile device communicating with a mobile switching center (MSC) in one example comprises steps of attempting to deliver the mobile terminated call to a mobile device, receiving a message that the mobile device is no longer in the location area served by the visiting MSC and forwarding the mobile terminated call to a different visiting MSC. The mobile terminated call is forwarded directly from one VMSC to another VMSC without requiring two potentially international calls to be placed serially from the GMSC to a VMSC. This method of Mobile Termination Roaming Forwarding can reduce substantial delay in call setup while saving network resources during establishment of the first call.
1. A method for delivering a mobile terminated call to a mobile device, said method, performed by a VMSC/VLR (visiting mobile switching center/visiting location register), comprising the steps of:
receiving an initial address message (IAM) for the mobile device from a gateway mobile switching center (GMSC);
paging the mobile device that is referenced by the IAM;
receiving a cancel location message from the home location register (HLR) assigned to the mobile device, the cancel location message including a mobile termination roaming forwarding (MTRF) flag and addresses of a new VMSC/VLR;
sending a provide roaming number (PRN) message with a MTRF flag to the new VMSC/VLR;
receiving a PRN Response message from the new VMSC/VLR; and
forwarding the IAM to the new VMSC/VLR.
2. The method of claim 1 further comprising steps prior to the first receiving step of:
receiving a provide routing number (PRN) message from the HLR; and
sending a provide routing number acknowledge message (PRN ACK) to the HLR.
3. The method of claim 1 wherein the mobile device initiates a location update procedure after the IAM message is received.
4. The method of claim 1 further comprising the steps of:
if the MTRF flag is not set in the cancel location message, requesting the GMSC to reroute the call to the new VMSC/VLR; and
if the MTRF flag is set in the cancel location message, checking roaming agreements with the new VMSC/VLR in response to the cancel location message and if MTRF is not allowed, requesting the GMSC to reroute the call to the new VMSC/VLR.
5. The method of claim 1 wherein the HLR, old VMSC/VLR and new VMSC/VLR are located in the same Public Land Mobile Network (PLMN).
6. The method of claim 1 wherein the HLR, old VMSC/VLR and new VMSC/VLR are not located in the same Public Land Mobile Network (PLMN) and each checks roaming agreements before performing allowing a MTRF operation.
7. The method of claim 1 wherein the mobile device is an LTE (Long Term Evolution) device, the GMSC is a 2G/3G device, the new VMSC/VLR is an MSC/VLR designated to handle circuit-switched calls for LTE mobile devices and the paging step further comprises the step of sending a circuit-switched page to an LTE radio in the mobile device.
8. A VMSC/VLR (visiting mobile switching center/visiting location register) for use in a telecommunications network for delivering a mobile terminated call to a mobile device, said VMSC/VLR configured to perform the following steps:
receiving an initial address message (IAM) for the mobile device from a gateway mobile switching center (GMSC);
paging the mobile device that is referenced by the IAM;
receiving a cancel location message from the home location register (HLR) assigned to the mobile device, the cancel location message including a mobile termination roaming forwarding (MTRF) flag and addresses of a new VMSC/VLR;
sending a provide roaming number (PRN) message with a MTRF flag to the new VMSC/VLR;
receiving a PRN Response message from the new VMSC/VLR; and
forwarding the IAM to the new VMSC/VLR.
9. An apparatus of claim 8 , said apparatus further configured to perform the following step of:
sending a provide routing number acknowledge message (PRN ACK) to the HLR in response to a PRN message from the HLR in response to the SRI message from the GMSC and wherein the IAM message is received after the PRN ACK message is sent.
10. An apparatus of claim 8 , said apparatus further configured to perform the following steps:
if the MTRF flag is not set in the cancel location message, requesting the GMSC to reroute the call to the new VMSC/VLR; and
if the MTRF flag is set in the cancel location message, checking roaming agreements with the new VMSC/VLR in response to the cancel location message and if MTRF is not allowed, requesting the GMSC to reroute the call to the new VMSC/VLR.
11. An apparatus of claim 8 , said apparatus wherein the HLR, old VMSC/VLR and new VMSC/VLR are not located in the same Public Land Mobile Network (PLMN) and each checks roaming agreements before performing allowing a MTRF operation.
12. An apparatus of claim 8 , said apparatus wherein the mobile device is an LTE (Long Term Evolution) device, the GMSC is a 2G/3G device, the new VMSC/VLR is an MSC/VLR designated to handle circuit-switched calls for LTE mobile devices and the paging step further comprises the step of sending a circuit-switched page to an LTE radio in the mobile device.