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

• US 9,197,450 B2
• Filed: 06/25/2012
• Issued: 11/24/2015
• 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 Jr.
• Primary Examiner(s): Jagannathan, Melanie
• Application Number:
  US13/532,344
• Publication Number:
  US 20120263174A1
• Time in Patent Office: 1,247 Days
• Field of Search: 370352-356, 370/401
• US Class Current: 1/1
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04M 7/127 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 method of converting a call, passed over a switched telephone network, into a voice over Internet Protocol (VoIP) call, comprising:

receiving, at an intermediate call protocol conversion gateway, circuit-switched call signaling from a mobile switching center (MSC);

converting, at said intermediate call protocol conversion gateway, said circuit-switched call signaling into session initiation protocol (SIP)-based call signaling;

transmitting, from said intermediate call protocol conversion gateway, said SIP-based call signaling to a physical VoIP positioning center (VPC);

receiving routing instruction back from said VoIP positioning center; and

routing said received routing instruction back to said mobile switching center (MSC).

2. The method of converting a call, passed over a switched telephone network, into a VoIP call according to claim 1, wherein:

said circuit-switched call signaling is signaling system number 7 (SS7) MAP/Lg+-based call signaling.

3. The method of converting a call, passed over a switched telephone network, into a VoIP call according to claim 1, further comprising:

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

4. The method of converting a call, passed over a switched telephone network, into a VoIP call according to claim 1, wherein:

said circuit-switched call signaling relates to a VoIP wireless call made via a local area network.

5. The method of converting a call, passed over a switched telephone network, into a VoIP call according to claim 4, wherein:

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

6. The method of converting a call, passed over a switched telephone network, into a VoIP call according to claim 1, wherein:

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

7. The method of converting a call, passed over a switched telephone network, into a VoIP call according to claim 1, further comprising:

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