Ss7 isup to sip based call signaling conversion gateway for wireless voip e911

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.

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.