System and method of handling emergency calls from roaming mobile stations in a radio telecommunications network

• US 6,240,284 B1
• Filed: 11/06/1998
• Issued: 05/29/2001
• Est. Priority Date: 11/06/1998
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Nguyen, Binh, Bugnon, Jacques
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): LE, LANA N
• Application Number:
  US09/188,070
• Time in Patent Office: 935 Days
• Field of Search: 455/404, 455/414, 455/433, 455/432, 455/436, 455/435, 455/438, 455/439, 379/45
• US Class Current: 455/404.1
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 76/50 for emergency connections
• CPC Class Codes: H04W 8/02 Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks

Abstract

A system and method in a radio telecommunications network for reconnecting an emergency call between a roaming mobile station with an emergency (emergency MS) and a public safety answering point (PSAP) when the call has been disconnected before the call was finished. The network includes a serving mobile switching center (MSC) serving the emergency MS, a border MSC bordering the serving MSC, and a home location register (HLR) that stores features and subscription data for the emergency MS. When the emergency call begins, a hotlining feature for the emergency MS is activated in the HLR which automatically reconnects the emergency MS to the PSAP when the MS accesses the network through a registration or by originating a subsequent call. Inter-exchange messages ensure that the emergency MS is automatically connected to the PSAP, even if the emergency MS accesses the network in the border MSC.

Claims

1. In a radio telecommunications network having a serving mobile switching center (MSC) serving a mobile station with an emergency (emergency MS), and a home location register (HLR) that stores features and subscription data for the emergency MS, a method of reconnecting an emergency call between the emergency MS and a public safety answering point (PSAP) when the call has been disconnected before the call was finished, said method comprising the steps of:

activating in the HLR, a hotlining feature for the emergency MS when the emergency call is begun;

determining that the emergency call was disconnected before the call was finished;

determining that the emergency MS attempts to access the network after the emergency call was disconnected; and

automatically connecting the emergency MS to the PSAP.

2. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 1 wherein the step of activating a hotlining feature includes setting a hotlining category in the HLR to activate the hotlining feature.

3. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 1 further comprising, after the step of determining that the emergency call was disconnected before the call was finished, the step of attempting by the serving MSC to reconnect the emergency call to the PSAP.

4. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 1 wherein the step of determining that the emergency MS attempts to access the network includes determining that the emergency MS attempts to originate a subsequent call.

5. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 4 wherein the step of automatically connecting the emergency MS to the PSAP includes the steps of:

instructing the serving MSC to automatically connect the emergency MS to the PSAP when the emergency MS accesses the network; and

automatically connecting the emergency MS to the PSAP when the emergency MS originates a subsequent call in the serving MSC.

6. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 1 wherein the step of determining that the emergency MS attempts to access the network includes determining that the emergency MS registers with the serving MSC.

7. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 6 wherein the step of automatically connecting the emergency MS to the PSAP includes the steps of:

instructing the serving MSC to automatically connect the emergency MS to the PSAP when the emergency MS accesses the network; and

automatically connecting the emergency MS to the PSAP when the emergency MS registers with the serving MSC.

8. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 1 wherein the step of determining that the emergency MS attempts to access the network includes determining that the emergency MS registers with a border MSC.

9. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 8 wherein the step of automatically connecting the emergency MS to the PSAP includes the steps of:

instructing the border MSC to automatically connect the emergency MS to the PSAP when the emergency MS accesses the network; and

automatically connecting the emergency MS to the PSAP when the emergency MS originates a subsequent call in the border MSC.

10. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 8 wherein the step of automatically connecting the emergency MS to the PSAP includes the steps of:

instructing the border MSC to automatically connect the emergency MS to the PSAP when the emergency MS accesses the network; and

automatically connecting the emergency MS to the PSAP when the emergency MS registers with the border MSC.

11. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 1 wherein the step of activating a hotlining feature in the HLR includes the steps of:

sending a message from the serving MSC to the HLR, the message identifying that the emergency MS has an unfinished emergency call, and providing a PSAP number to the HLR; and

setting a hotlining category in the HLR to activate the hotlining feature.

12. The method of reconnecting an emergency call between an emergency MS and a PSAP of claim 11 further comprising the steps of:

determining in the PSAP that the emergency call has been properly completed;

sending a message from the PSAP to the HLR identifying that the emergency call has been properly completed; and

setting the hotlining category in the HLR to deactivate the hotlining feature.

13. In a radio telecommunications network having a plurality of mobile switching center (MSCs) including a serving MSC, a mobile station with an emergency (emergency MS), and a home location register (HLR) that stores features and subscription data for the emergency MS, a method of reconnecting an emergency call between the emergency MS and a public safety answering point (PSAP) when the call has been disconnected before the call was finished, said method comprising the steps of:

activating in the HLR, a hotlining feature for the emergency MS when the emergency call is begun;

determining that the call was disconnected before the call was finished;

attempting by the serving MSC to reconnect the emergency call;

determining that the emergency MS registered within the service area of a second MSC other than the serving MSC;

sending from the HLR to the serving MSC, a registration cancellation (REGCANC) message identifying the emergency MS;

sending a return REGCANC message from the serving MSC to the HLR identifying that the emergency MS has an unfinished emergency call and providing a PSAP number to the HLR;

sending an instruction from the HLR to the second MSC instructing the second MSC to automatically connect the emergency MS to the PSAP if the emergency MS attempts to access the network in the second MSC;

determining that the emergency MS attempts to access the network in the second MSC; and

automatically connecting the call from the emergency MS to the PSAP.

14. In a radio telecommunications network having a serving mobile switching center (MSC) serving a mobile station with an emergency (emergency MS), and a home location register (HLR) that stores features and subscription data for the emergency MS, a system for reconnecting an emergency call between the emergency MS and a public safety answering point (PSAP) when the call has been disconnected before the call was finished, said system comprising:

means within the HLR for activating a hotlining feature for the emergency MS when the emergency call is begun;

means within the serving MSC for determining that the emergency call was disconnected before the call was finished;

means within the serving MSC for determining that the emergency MS attempts to access the network after the emergency call was disconnected; and

means within the serving MSC for automatically connecting the emergency MS to the PSAP.

15. In a radio telecommunications network having a serving mobile switching center (MSC) serving a mobile station with an emergency (emergency MS), a border MSC bordering the serving MSC, and a home location register (HLR) that stores features and subscription data for the emergency MS, a system for reconnecting an emergency call between the emergency MS and a public safety answering point (PSAP) when the call has been disconnected before the call was finished, said system comprising:

means within the HLR for activating a hotlining feature for the emergency MS when the emergency call is begun;

means within the serving MSC for determining that the emergency call was disconnected before the call was finished;

means for informing the HLR that the emergency call was disconnected before the call was finished;

means wit the border MSC for determining that the emergency MS attempts to access the network in the border MSC after the emergency call was disconnected;

means for instructing the border MSC to automatically connect the emergency MS to the PSAP; and

means within the border MSC for automatically connecting the emergency MS to the PSAP.