Determining the geographical location from which an emergency call originates in a packet-based communications network

• US 20050190892A1
• Filed: 06/04/2004
• Published: 09/01/2005
• Est. Priority Date: 02/27/2004
• Status: Active Grant

• Current Assignee: Avaya Incorporated
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Broda, Maciej, Dawson, Martin C., Lewis, Mark
• Granted Patent: US 7,177,399 B2
• Time in Patent Office: Days
• US Class Current: 379/37
• CPC Class Codes: H04M 2242/04 for emergency applications
• CPC Class Codes: H04M 2242/30 Determination of the location of a subscriber
• CPC Class Codes: H04M 3/42229 Personal communication services, i.e. services related to one subscriber independent of his terminal and/or location diverting calls from one subscriber to another subscriber, i.e. two different subscriptions H04M3/54; selecting arrangements in intelligent networks H04Q3/005
• CPC Class Codes: H04M 3/42348 Location-based services which utilize the location information of a target
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

In order that emergency service vehicles can be dispatched to the correct destination promptly, accurate information about the location of the caller is needed. Another problem concerns routing emergency calls to the correct destination. For emergency calls a universal code is used such as 911 in North America and 112 in Europe. This universal code cannot be used to identify the destination of the call. These problems are particularly acute for nomadic communications systems such as voice over internet protocol communications networks. That is because user terminals change network location. These problems are solved by enabling the geographical location of the emergency caller to be determined by entities within a packet-based network without the need for modification of existing emergency services network infrastructure.

Claims

1. A method of providing a routing key for routing an emergency call from a packet-based communications network node to an emergency services network node in a switched telephone network, said method comprising the steps of:

(i) at a node in the packet-based communications network, receiving information about the geographical location from which the emergency call originates;

(ii) generating a routing key on the basis of the received information and pre-specified information about geographical locations served by particular emergency service network nodes.

2. A method as claimed in claim 1 wherein said step (i) further comprises receiving at the node a call-back number from which the emergency call originates.

3. A method as claimed in claim 1 which further comprises storing said generated routing key together with the received information about geographical location at the node in the packet-based communications network.

4. A method as claimed in claim 3 which further comprises providing the stored information to the switched telephone network for receipt by a public safety answering point (PSAP).

5. A method as claimed in claim 4 wherein said stored information is provided via an E2 interface.

16. A computer program stored on a computer readable medium and arranged to control a location gateway server in a packet-based communications network in order to carry out the method of claim 1.

6. A packet-based communications network node for providing a routing key for routing an emergency call from the packet-based communications network to an emergency services network node in a switched telephone network, said node comprising:

(i) an input arranged to receive information about the geographical location from which the emergency call originates;

(ii) a processor arranged to generate a routing key on the basis of the received information and pre-specified information about geographical locations served by particular emergency service network nodes.

7. A packet-based communications network comprising a node as claimed in claim 6.

8. A method of routing an incoming emergency call in a packet-based communications network to an appropriate emergency services answering point in a switched telephone network, said method comprising:

(i) at a packet-based call server, receiving the emergency call;

(ii) at a location gateway server, receiving a geographical location from which the call originated and using that to generate a routing key;

(iii) at the call server, routing the emergency call using the generated routing key.

9. A method as claimed in claim 8 wherein said geographical location information is received at the location gateway server as a result of polling a location information server.

10. A method as claimed in claim 8 wherein said geographical location information is received at the location gateway server from the call server.

11. A method as claimed in claim 8 wherein said emergency call comprises a geographical location from which the call originated.

12. A method as claimed in claim 8 wherein said packet-based communications network is a voice over internet protocol network.

13. A method as claimed in claim 8 wherein said emergency call originates from a nomadic entity.

14. A method as claimed in claim 8 which further comprises, at the location gateway server, storing the generated routing key together with the determined geographical location.

15. A method as claimed in claim 14 which further comprises making the stored information accessible to an automatic location identification node in an emergency services network.