SS7 MAP/Lg+ to SIP based call signaling conversion gateway for wireless VoIP E911

• US 8,208,461 B2
• Filed: 05/04/2006
• Issued: 06/26/2012
• Est. Priority Date: 04/04/2006
• Status: Expired due to Fees

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Inventors: Mitchell, Don
• Primary Examiner(s): Nawaz, Asad M
• Assistant Examiner(s): HAMEL, JOEL A
• Application Number:
  US11/417,126
• Publication Number:
  US 20070263610A1
• Time in Patent Office: 2,245 Days
• Field of Search: 370352-356, 370466-467, 455/414.4, 455/521, 379/45
• US Class Current: 370/352
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04M 7/127 where the session control protocols comprise SIP and SS7
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]

Abstract

An SS7-based call protocol conversion gateway that translates between circuit-switched SS7 protocols and session initiation protocol (SIP) oriented protocol, allowing an E911 call initiated over a switched network to be routed by a VoIP network. The SS7-based call protocol conversion gateway provides a PSAP with MSAG quality (street address) information about a VoIP dual mode phone user without the need for a wireless carrier to invest in building out an entire VoIP core. Thus, wireless carriers may continue signaling the way they are today, i.e., using the J-STD-036 standard for CDMA and GSM in North America, yet see benefits of a VoIP network core, i.e., provision of MSAG quality location data to a PSAP.

Claims

1. A call protocol conversion gateway between an SS7 MAP/Lg+ based communication network and a physical voice over Internet (VoIP) positioning center, comprising:

a first physical interface adapted to receive signaling system number 7 (SS7) MAP/Lg+-based call signaling;

a software module adapted to convert said SS7 MAP/Lg+ based call signaling into session initiation protocol (SIP)-based call signaling; and

a second physical interface adapted to pass said SS7 MAP/Lg+-to-SIP converted SIP call signaling to said physical voice over Internet (VoIP) positioning center;

wherein the gateway receives a routing instruction from a VoIP positioning center (VPC), including an emergency services query key (ESQK) and a trunk select code; and

translates said ESQK into an emergency services routing key (ESRK).

2. The call protocol conversion gateway according to claim 1, wherein:

said SS7 call signaling relates to a wireless 911 call.

3. The call protocol conversion gateway according to claim 2, wherein:

said SS7 call signaling relates to a VoIP wireless 911 call.

4. The call protocol conversion gateway according to claim 1, wherein:

said SS7 call signaling relates to a VoIP wireless call made via a local area network.

5. The call protocol conversion gateway according to claim 4, wherein:

said local area network is a wireless fidelity (WiFi) network.

6. A method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP), comprising:

receiving, at an intermediate call protocol conversion gateway between an SS7 MAP/Lg+ based communication network and a physical voice over Internet (VoIP) positioning center, a voice over Internet protocol (VoIP) call from a VoIP phone;

converting, at said intermediate call protocol conversion gateway, SS7 MAP/Lg+ based call signaling into session initiation protocol (SIP) call signaling; and

passing, from said intermediate call protocol conversion gateway, said SS7 MAP/Lg+-to-SIP converted SIP call signaling to said voice over Internet (VoIP) positioning center;

receiving a routing instruction from a VoIP positioning center (VPC), including an emergency services query key (ESQK) and a trunk select code; and

translating said ESQK into an emergency services routing key (ESRK).

7. The method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 6, wherein:

said local area network is a wireless fidelity (WiFi) network.

8. The method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 6, wherein:

said VoIP phone is a wireless phone.

9. The method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 6, wherein:

said VoIP phone is a dual mode phone.

10. The method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 9, wherein:

said dual mode phone has a first mode operable in a cellular phone network, and a second mode operable in a wireless fidelity (WiFi) network.

11. The method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 6, wherein:

said SIP-based call signaling includes use of a SIP INVITE command.

12. The method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 6, further comprising:

assigning routing based upon a location retrieved from a location information service/subscriber line database (LIS/SLDB).

13. A method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP), comprising:

receiving, at an intermediate call protocol conversion gateway between an SS7 MAP/Lg+ based communication network and a physical voice over Internet (VoIP) positioning center, a voice over Internet protocol (VoIP) call from a VoIP phone;

converting, at said intermediate call protocol conversion gateway, SS7 MAP/Lg+ based call signaling into session initiation protocol (SIP) call signaling;

passing, from said intermediate call protocol conversion gateway, said SIP call signaling to said voice over Internet (VoIP) positioning center;

receiving a routing instruction from a VoIP positioning center (VPC), including an emergency services query key (ESQK) and a trunk select code; and

translating said ESQK into an emergency services routing key (ESRK).

14. The method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 13, wherein:

said trunk select code is further translated into a public switched telephone network phone number to provide a last routing option (LRO).

15. The method of converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 13, further comprising:

egressing said VoIP call based upon said ESRK and said trunk select code to a proper PSAP.

16. A method for converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP), comprising:

receiving a voice over Internet protocol (VoIP) call from a VoIP phone via a local area network;

routing said VoIP call using signaling system number 7 (SS7) MAP/Lg+ based call signaling;

converting said SS7 MAP/Lq+ based call signaling into session initiation protocol (SIP) call signaling;

passing said SIP call signaling to a voice over Internet (VoIP) positioning center;

receiving a routing instruction from a VoIP positioning center (VPC), including an emergency services query key (ESQK) and a trunk select code;

translating said ESQK into an emergency services routing key (ESRK).

17. The apparatus method for converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 16, wherein:

said trunk select code is further translated into a public switched telephone network phone number to provide a last routing option (LRO).

18. The method for converting a VoIP call, passed over a switched telephone network, into a VoIP call for presentation to a public safety access point (PSAP) according to claim 16, further comprising:

egressing said VoIP call based upon said ESRK and said trunk select code to a proper PSAP.