SS7 ANSI-41 to SIP based call signaling conversion gateway for wireless VoIP E911

摘要

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.

主权项

1. A call protocol conversion gateway, comprising:
a mobile switching center to receive a VoIP call over signaling system number 7 (SS7)—based call signaling; a SS7-to-SIP gateway to convert said SS7 ISUP based call signaling into session initiation protocol (SIP)—based call signaling, and to pass said SIP call signaling to a voice over Internet (VoIP) positioning center (VPC);wherein the VoIP positioning center (VPC) assigns routing based upon the location retrieved from a location information service/subscriber line database (LIS/SLDB)
wherein said SS7-to-SIP gateway converts an emergency services query key (ESQK) into an emergency services routing key (ESRK), and provides said converted ESRK to said mobile switching center for passage to an appropriate selective router.