Non-validated emergency calls for all-IP 3GPP IMS networks

摘要

An emergency call in an all Internet Protocol (IP) network having GPRS access is able to be completed without a valid SIM. A valid Subscriber Identity Module is substituted for the missing or invalid SIM only when an emergency call is attempted. The emergency call is either sent via an IMSI from an embedded SIM provided by the UE making the emergency call, or the emergency call is modified with an IMSI substituted by an Emergency SIM Pool Function prior to being sent to the HLR for validation. The SIM is valid for the UE's emergency call so the emergency call is completed because the UE is considered validated by the network.

主权项

1. A method for completing an emergency call in an all Internet Protocol (IP) network having GPRS access, the method comprising:
implementing, in a node in the IP network, a pool of stored, substitute Subscriber Identity Modules (SIMs) that are designated as an Emergency SIM Pool Function (ESPF); receiving, at the node, an initial emergency call request message from a User Equipment (UE) with no SIM card or an invalid SIM card, the node being remote from the UE; presenting the initial emergency call request message to the UE's home network HLR; upon rejection of the initial emergency call request message as invalid, the ESPF intercepting a subsequent emergency call request message from the UE, the subsequent emergency call request message including an emergency IMSI formed by concatenating a portion of the International Mobile Equipment Identity (IMEI) of the UE with the subsequent emergency call request; substituting a valid IMSI for the emergency IMSI using a SIM from the ESPF; forwarding the subsequent emergency call request message with the valid IMSI to the IP network's HLR, wherein the valid IMSI is authenticated; and completing the emergency call by routing the authenticated emergency request message to a Public Safety Answering Point.