Call-back to a UE that has made an emergency call via a visited IMS network

摘要

Exemplary methods for establishing an emergency call and an emergency call-back for a first User Equipment (UE) communicatively coupled to a visited Internet Protocol Multimedia Subsystem (IMS) network includes establishing an emergency call by the first UE sending an emergency call request to a Proxy Call Session Control Function (P-CSCF) in the visited IMS network. The methods further include providing, from the P-CSCF to a Serving CSCF (S-CSCF) in a home IMS network for the first UE, information comprising an indication that the emergency call has been performed and an equipment identifier of the first UE. The methods further include receiving, in the S-CSCF, an emergency call-back request from an emergency call-center, and using, in the S-CSCF, information comprised in the received emergency call-back and the information provided by the P-CSCF, to route the emergency call-back to the first UE and/or to a second UE.

主权项

1. A method of establishing an emergency call and an emergency call-back for a first User Equipment (UE) communicatively coupled to a visited Internet Protocol Multimedia Subsystem (IMS) network, the method comprising:
establishing an emergency call by the first UE sending an emergency call request to a Proxy Call Session Control Function (P-CSCF) in the visited IMS network, wherein the first UE is a mobile equipment operating in a telecommunication network and having a unique equipment identifier to identify the first UE; sending, from the P-CSCF to an Emergency CSCF (E-CSCF) in the visited IMS network, an invite signal enabling routing of the emergency call through the E-CSCF in the visited IMS network without routing the emergency call through a Serving CSCF (S-CSCF) in a home IMS network of the first UE; providing, from the P-CSCF to the S-CSCF in the home IMS network for the first UE, information comprising an indication that the emergency call has been performed by the visited IMS network and the equipment identifier of the first UE; receiving, in the S-CSCF, an emergency call-back request from an emergency call-centre; and using, in the S-CSCF, information comprised in the received emergency call-back and the information provided by the P-CSCF, to route the emergency call-back to the first UE or to a second UE, or to both UEs.