Abstract: A method, apparatus and computer program product are provided to facilitate the handover from a packet switched network to a circuit switched network while an Internet protocol (IP) multimedia subsystem (IMS) session is ongoing. In the context of a method, a notification is received of the handover from a packet switched network to a circuit switched network while an IMS session is ongoing. The method also receives an indication that an emergency call service is active in the IMS session and determines that media resources in the circuit switched network are required to support the emergency call service, as supplemented by a minimum set of emergency related data, that is active in the IMS session. The method may further include causing the media resources to be reserved in the circuit switched network to support the emergency call service that is active in the IMS session.

Abstract: Methods and apparatus, including computer program products, are provided for power optimization. In one aspect there is provided a method. The method may include receiving, at a user equipment, configuration information including an active time wherein the active time is less than an allowed clock drift of a clock at the user equipment; and receiving, at the user equipment, data sent in advance by an application server, wherein the advance comprises a time based on at least the allowed clock drift. Related apparatus, systems, methods, and articles are also described.

Abstract: A method, apparatus and computer program product are provided to facilitate the handover from a packet switched network to a circuit switched network while an Internet protocol (IP) multimedia subsystem (IMS) session is ongoing. In the context of a method, a notification is received of the handover from a packet switched network to a circuit switched network while an IMS session is ongoing. The method also receives an indication that an emergency call service is active in the IMS session and determines that media resources in the circuit switched network are required to support the emergency call service, as supplemented by a minimum set of emergency related data, that is active in the IMS session. The method may further include causing the media resources to be reserved in the circuit switched network to support the emergency call service that is active in the IMS session.

Abstract: A method, apparatus and computer program product are provided for determining IMS connectivity through non-3GPP access networks. A method is provided for receiving, in response to an access network query, an available public land mobile network (PLMN) list; wherein the PLMN list comprises an IP multimedia subsystem access point name (IMS APN) indication for the respective PLMNs with IMS connectivity; determining, using a processor, if a connection to a home PLMN (HPLMN) can be established using an IMS APN associated with a PLMN from the PLMN list; and prioritizing available wireless local area networks (WLAN) based on the determining if a connection to the HPLMN can be established using the IMS APN for the respective PLMNs of the PLMN list associated with the respective WLANs.

Abstract: A method and apparatus are provided for facilitating communication session continuity. A method may include receiving, at a terminal, an identifier associated with an EATF (emergency access transfer function). The method may further include determining that the terminal has undergone a reverse SRVCC (Single Radio Voice Call Continuity) handover from a circuit switched access to a packet switched access while engaged in an active emergency session. The method may additionally include, responsive to the determination, using the identifier to set up an emergency session transfer request to the EATF to cause creation of a bearer for the emergency session on the packet switched access. A corresponding apparatus is also provided.

Abstract: Methods and apparatus, including computer program products, are provided for power optimization. In one aspect there is provided a method. The method may include receiving, at a user equipment, configuration information including an active time wherein the active time is less than an allowed clock drift of a clock at the user equipment; and receiving, at the user equipment, data sent in advance by an application server, wherein the advance comprises a time based on at least the allowed clock drift. Related apparatus, systems, methods, and articles are also described.

Abstract: An example apparatus is caused to receive a message inviting a user equipment (UE) to participate in an emergency communication session with an originating node, where the user equipment is registered with an Internet Protocol Multimedia Subsystem (IMS). The apparatus is caused to identify a type of registration of the UE with the IMS, and 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 transfer function may be a domain transfer function or emergency access transfer function of the IMS. The apparatus is also caused to 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.

Abstract: Various methods for implementing a wait period for single radio continuity transfers are provided. One example method includes obtaining a timer value, where the timer value is based on a communications delay to a far end device. The communications delay to the far end device may be determined during session establishment with the far end device. The example method also includes implementing a wait period for a duration of the timer value, and, in response to completion of the wait period, triggering a single radio continuity network transfer. Similar and related example methods and example apparatuses are also provided.

Abstract: A method and apparatus are provided for facilitating communication session continuity. A method may include receiving, at a terminal, an identifier associated with an EATF (emergency access transfer function). The method may further include determining that the terminal has undergone a reverse SRVCC (Single Radio Voice Call Continuity) handover from a circuit switched access to a packet switched access while engaged in an active emergency session. The method may additionally include, responsive to the determination, using the identifier to set up an emergency session transfer request to the EATF to cause creation of a bearer for the emergency session on the packet switched access. A corresponding apparatus is also provided.

Abstract: An example apparatus is caused to receive a message inviting a user equipment (UE) to participate in an emergency communication session with an originating node, where the user equipment is registered with an Internet Protocol Multimedia Subsystem (IMS). The apparatus is caused to identify a type of registration of the UE with the IMS, and 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 transfer function may be a domain transfer function or emergency access transfer function of the IMS. The apparatus is also caused to 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.

Abstract: Various methods for implementing a wait period for single radio continuity transfers are provided. One example method includes obtaining a timer value, where the timer value is based on a communications delay to a far end device. The communications delay to the far end device may be determined during session establishment with the far end device. The example method also includes implementing a wait period for a duration of the timer value, and, in response to completion of the wait period, triggering a single radio continuity network transfer. Similar and related example methods and example apparatuses are also provided.