SS7 ISUP to SIP based call signaling conversion gateway for wireless VoIP E911

• US 8,155,109 B2
• Filed: 05/04/2006
• Issued: 04/10/2012
• 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): Cheng, Joe
• Assistant Examiner(s): HAMEL, JOEL A
• Application Number:
  US11/417,128
• Publication Number:
  US 20070263611A1
• Time in Patent Office: 2,168 Days
• Field of Search: 370352-356, 370466-467, 379/45, 455/414.4, 455/521
• 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: H04L 65/1104 Session initiation protocol [SIP]
• 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
• 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]

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 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 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) ISUP based call signaling;

converting said SS7 ISUP based call signaling into session initiation protocol (SIP) call signaling;

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

receiving 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).

2. 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 1, wherein:

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

3. 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 2, further comprising:

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