Patent ID: 9143989
Filing Date: 2015-09-22
Classification: H04W

Abstract:
1. An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to at least: receive a message inviting a user equipment to participate in an emergency communication session with an originating node, the user equipment being registered with an Internet Protocol Multimedia Subsystem (IMS), the originating node comprising a public safety answering point inviting the user equipment to participate in an emergency callback session, or an application server inviting the user equipment to participate in an emergency click-to-dial session, wherein another message inviting the user equipment to participate in the emergency communication session is received in response to an inadvertent release of the emergency communication session; identify a type of registration of the user equipment with the IMS; select a transfer function of the IMS to anchor the emergency communication session based on the identified type of registration of the user equipment with the IMS, the selected transfer function comprising a domain transfer function or an emergency access transfer function of the IMS; and prepare the message for transmission to the selected transfer function to thereby enable the selected transfer function to anchor the emergency communication session and further communicate with one or more other components of the IMS to establish the emergency communication session with the user equipment.