SS7 ISUP TO SIP BASED CALL SIGNALING CONVERSION GATEWAY FOR WIRELESS VOIP E911
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.
1 . (canceled)
2 . A call protocol conversion gateway comprising one or more computing devices, the call protocol conversion gateway having machine executable instructions causing the call protocol conversion gateway to:
receive Signaling System Number 7 (SS7) call signaling for a Voice over Internet Protocol (VoIP) call from a mobile switching center (MSC);
convert the SS7 call signaling into session initiation protocol (SIP) call signaling;
send the SIP call signaling to a VoIP positioning center (VPC);
receive routing information for the VoIP call from the VPC, the routing information including an emergency services query key (ESQK) and an emergency services routing number (ESRN);
determine routing elements for the VoIP call based on the routing information for the VoIP call, wherein the routing elements includes an emergency services routing key (ESRK) and a trunk select code for the VoIP call; and
send the routing elements for the VoIP call to the MSC.
3 . The call protocol conversion gateway of claim 2 , wherein:
the routing elements further include a Public Switched Telephone Network (PSTN) number for the VoIP call.
4 . The call protocol conversion gateway of claim 3 , wherein:
the PSTN number is a last routing option for the VoIP call.
5 . The call protocol conversion gateway of claim 4 , wherein:
the last routing option corresponds to a contingency routing number.
6 . The call protocol conversion gateway of claim 4 , wherein:
the last routing option corresponds to a routing number associated with a national call center.
7 . The call protocol conversion gateway of claim 2 , wherein:
the routing elements are Wireless E9-1-1 elements.
8 . The call protocol conversion gateway of claim 7 , wherein:
the routing information comprises National Emergency Number Association (NENA) i2 standard elements.
9 . The call protocol conversion gateway of claim 2 , wherein:
the VoIP call is a wireless 911 call.
10 . The call protocol conversion gateway of claim 2 , wherein:
the VoIP call originates from a local area network (LAN).
11 . The call protocol conversion gateway of claim 10 , wherein:
the VoIP call originates from a WiFi network operating on the LAN.
12 . The call protocol conversion gateway of claim 2 , wherein:
the converting includes translating the SS7 call signaling for the VOIP call into SIP INVITE parameters.
13 . The call protocol conversion gateway of claim 12 , wherein:
the SIP INVITE parameters includes a callback number for the VoIP caller.
14 . The call protocol conversion gateway of claim 12 , wherein:
the SIP INVITE parameters includes a TO field addressed to 911.
15 . A method comprising:
converting Signaling System Number 7 (SS7) call signaling for a Voice over Internet Protocol (VoIP) call into session initiation protocol (SIP) call signaling;
receiving routing information for the VoIP call from a VoIP Positioning Center (VPC), the routing information including an emergency services query key (ESQK) and an emergency services routing number (ESRN);
determining routing elements for the VoIP call based on the routing information for the VoIP call, wherein the routing elements includes an emergency services routing key (ESRK) and a trunk select code for the VoIP call; and
sending the routing elements for the VoIP call to a Mobile Switching Center (MSC).
16 . The method of claim 15 , wherein:
the routing elements further include a Public Switched Telephone Network (PSTN) number for the VoIP call.
17 . The method of claim 16 , wherein:
the PSTN number is a last routing option for the VoIP call.
18 . The call protocol conversion gateway of claim 15 , wherein:
the routing elements are Wireless E9-1-1 elements.
19 . A system comprising:
a mobile switching center (MSC) that receives a Voice over Internet Protocol (VoIP) call with Signal System Number 7 (SS7) signaling;
a gateway that:
converts the SS7 call signaling for the VoIP call to Session Initiated Protocol (SIP) call signaling;
receives routing information for the VoIP call from a VoIP Positioning Center (VPC), wherein the routing elements comprises National Emergency Number Association (NENA) i2 standard elements;
determines Wireless E 9-1-1 elements for the VoIP call based on the routing information for the VoIP call; and
sends the Wireless E 9-1-1 elements to the MSC.
20 . The system of claim 19 , wherein the E 9-1-1 elements include an emergency services routing key (ESRK) and a trunk select code for the VoIP call.