SS7 ANSI-41 to SIP Based Call Signaling Conversion Gateway for Wireless VoIP E911

• US 20120282881A1
• Filed: 07/18/2012
• Published: 11/08/2012
• Est. Priority Date: 04/04/2006
• Status: Active Grant

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Inventors: Mitchell, Don
• Granted Patent: US 8,774,171 B2
• Time in Patent Office: Days
• US Class Current: 455/404.1
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04M 7/0066 Details of access arrangements to the networks where the access arrangement is a PSTN/ISDN access H04M7/122
• 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 88/16 Gateway arrangements

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

1-18. -18. (canceled)

19. Apparatus 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:

means for receiving a VoIP 911 originating call to be converted to signaling system number 7 (SS7) ANSI-41 J-STD-036 transaction capability application part (TCAP)-based call signaling;

means for converting said VoIP 911 call using SS7 ANSI-41 J-STD-036 TCAP-based call signaling into session initiation protocol (SIP) call signaling; and

means for transmitting said SS7 ANSI-41 J-STD-036 transaction capability application part (TCAP)-to-SIP converted call signaling associated with said VoIP 911 originating call to a physical VoIP positioning center to retrieve routing information associated with said VoIP 911 originating call;

means for receiving routing instruction including an emergency services query key (ESQK) and a trunk select code; and

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

20. The apparatus 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 19, wherein:

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

21. The apparatus 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 19, wherein:

said physical VoIP phone is a dual mode wireless phone.

22. The apparatus 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 19, 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.

23. Apparatus 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:

means for receiving a voice over Internet protocol (VoIP) call from a VoIP phone;

means for routing said VoIP call using signaling system number 7 (SS7) ANSI-41 J-STD-036 transaction capability application part (TCAP)-based call signaling;

means for converting said SS7 ANSI-41 J-STD-036 TCAP-based call signaling into session initiation protocol (SIP) call signaling;

means for passing said SIP call signaling to a VoIP positioning center;

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

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

24. The apparatus 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 23, further comprising:

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