Abstract: When a user equipment is roaming in a visited network, mid-call handover from VoWiFi to VoLTE is controlled by policies enforced in the user equipment and the home network. An inter-operator policy and a subscription policy are stored in the home network and a user equipment policy is stored in the user equipment. The roaming user equipment registers in a visited network. Later, when mid-call handover to VoLTE on the visited network is desired, and also permitted by its user equipment policy, the user equipment sends a request containing a call-specific identifier which the responsible network entity in the home network compares with the registered handover parameter having regard to the inter-operator and subscription policies. If compliance with the policies is found, then the mid-call handover is proceeded with.

Abstract: A method of registering a subscriber in an IP Multimedia Subsystem (IMS), said subscriber being associated with an IMS Private User Identity (IMPI) and an IMS Public User Identity (IMPU) and further being associated with a 4G or 5G conforming User Equipment (UE). The method comprises: at the UE, generating a Temporary IMS Private User Identity (TIMPI) and a Temporary IMS Public User Identity (TIMPU) from a Globally Unique Temporary Identifier (GUTI) allocated by and received from a 4G or G network to temporarily identify the UE; sending an IMS registration request containing the TIMPI and the TIMPU from the UE to the IMS; at the IMS, using the TIMPI and the TIMPU to determine the GUTI, and communicating with the 4G or 5G network to determine, using the GUTI, an International Mobile Subscriber Identifier (IMSI) associated with the UE; at the IMS, using the IMSI to determine said IMPI and IMPU; and completing IMS registration of the subscriber using the IMPI and the IMPU.

Abstract: The embodiments herein relate to a method, performed by an IMS core network node (140), for handling end-to-end, E2E, delays for voice calls in a communication network (100). The communication network (100) comprises a packet core network node (130), the IMS core network node (140) and a radio network node (110). The radio network node (110) is serving one or more UEs (120). The IMS core network node (140) obtains a Packet Delay Budget, PDB, for the IMS core network node (140). The IMS core network node (140) estimates a packet delay related to a first voice call, wherein the packet delay is caused by the IMS core network. The IMS core network node (140) determines a PDB for a packet core network node (130) related to the first voice call, taking the estimated packet delay caused by the IMS core network into account. The IMS core network node (140) provides, to the packet core network node (130), the determined PDB for the packet core network node (130).

Abstract: A method of registering a subscriber in an IP Multimedia Subsystem (IMS), said subscriber being associated with an IMS Private User Identity (IMPI) and an IMS Public User Identity (IMPU) and further being associated with a 4G or 5G conforming User Equipment (UE). The method comprises: at the UE, generating a Temporary IMS Private User Identity (TIMPI) and a Temporary IMS Public User Identity (TIMPU) from a Globally Unique Temporary Identifier (GUTI) allocated by and received from a 4G or G network to temporarily identify the UE; sending an IMS registration request containing the TIMPI and the TIMPU from the UE to the IMS; at the IMS, using the TIMPI and the TIMPU to determine the GUTI, and communicating with the 4G or 5G network to determine, using the GUTI, an International Mobile Subscriber Identifier (IMSI) associated with the UE; at the IMS, using the IMSI to determine said IMPI and IMPU; and completing IMS registration of the subscriber using the IMPI and the IMPU.

Abstract: When a user equipment is roaming in a visited network, mid-call handover from VoWiFi to VoLTE is controlled by policies enforced in the user equipment and the home network. An inter-operator policy and a subscription policy are stored in the home network and a user equipment policy is stored in the user equipment. The roaming user equipment registers in a visited network. Later, when mid-call handover to VoLTE on the visited network is desired, and also permitted by its user equipment policy, the user equipment sends a request containing a call-specific identifier which the responsible network entity in the home network compares with the registered handover parameter having regard to the inter-operator and subscription policies. If compliance with the policies is found, then the mid-call handover is proceeded with.

Abstract: A method of operating a Proxy Call Session Control Function, P-CSCF, of an IP Multimedia Subsystem network. The method comprises maintaining a counter for each of a plurality of IP address domains containing IP addresses reachable via the P-CSCF, each IP address domain being associated with one of a plurality of packet gateways. A counter is updated in the event of the failure to deliver a SIP request to a User Equipment, UE, associated with an IP address within the associated IP address domain, at least until the counter reaches a predefined threshold. In the event that a counter reaches a predefined threshold, the P-CSCF responds to a received IMS request addressed to an IP address within the associated IP address domain by returning an indication that the associated terminating UE is unreachable.

Abstract: A method of managing an Evolved Packet System (EPS) fallback procedure in a 5GS network. The method comprises making available to the Access Mobility Function (AMF), a configuration parameter per Public Land Mobile Network (PLMN) indicating if early or late PCRF/PCF interaction with the IMS is used. Then, upon receipt by the network of a 5GS network registration request from a UE, the home PLMN of the UE is identified as is the configuration parameter for that PLMN. The identified parameter is then used to determine for the UE whether or not EPS fallback is available to the UE, and an indication of the determination is sent to the UE.

Abstract: A network node controls communication of user equipment in a mobile network with cellular network access and wireless local area network access. The network node receives from a further network node, information concerning a wireless local area network access to which the user equipment is attached and information concerning a cellular network access to which the user equipment is attached. On the basis of the received information, the network node controls whether to provide at least one service via the wireless local area network access or via the cellular network access.

Abstract: A method of anchoring a packet switched session of a subscriber comprises receiving a packet switched request for a session setup, and anchoring the packet switched session in a control node (MSC-S) of a visited network of the subscriber.

Abstract: An interruption of a call which is established or which is currently being established via an internet protocol domain of a mobile network may be avoided during a handling of a circuit switched signaling service to be terminated to a terminal and being different from a mobile terminating location request service.

Abstract: A telecommunications network has a packet switched domain for handling packet based calls and a circuit switched telephony domain for handling circuit switched calls. A node of the packet switched telephony domain decides whether to terminate a call to a user equipment using a packet based connection to the user equipment or using a circuit switched connection to the user equipment. In response to deciding to terminate the call using the circuit switched connection, the node sends, to a further node controlling routing of calls between the packet switched telephony domain and the circuit switched telephony domain, an indication that services related to the call are controlled in the packet switched telephony domain. In accordance with the indication, the further node may then adapt its control signalling with respect to a node of the circuit switched telephony domain.

Abstract: A method in an IP multimedia subsystem, IMS, of a telecommunications network. The loss of a secure association between a P-CSCF of the IMS and a user equipment, UE, served by the P-CSCF is detected, or a UE is relocated from a further P-CSCF to the first mentioned P-CSCF. The first mentioned P-CSCF sends a reregistration request to the UE; receives a SIP REGISTER message from the UE; and performs P-CSCF registration with the UE including establishing a new secure association with the UE.

Abstract: A mobile network provides first accesses implemented by a first radio access technology and second accesses implemented by a second radio access technology, which is different from the first radio access technology. A network node controls one or more of the first accesses records at least one mobility event. The mobility event corresponds to movement of a user equipment from one of the first accesses controlled by the network node to one of the second accesses. Further, the network node receives a query from a further network node. Depending on the recorded at least one mobility event, the network node responds to the query with an indication whether voice communication over packet switched access is supported for the user equipment.

Abstract: An interruption of a call which is established or which is currently being established via an internet protocol domain of a mobile network may be avoided during a handling of a circuit switched signaling service to be terminated to a terminal and being different from a mobile terminating location request service.

Abstract: A network node controls communication of user equipment in a mobile network with cellular network access and wireless local area network access. The network node receives from a further network node, information concerning a wireless local area network access to which the user equipment is attached and information concerning a cellular network access to which the user equipment is attached. On the basis of the received information, the network node controls whether to provide at least one service via the wireless local area network access or via the cellular network access.

Abstract: Methods, nodes, a terminal, a communication system and computer programs to be used in association with terminating a circuit switched signaling service to a terminal (108) via a circuit switched access of a mobile network (100) are described. In one method, the signaling service is different from a voice call via the circuit switched access and from a mobile terminating location request service. A call via an internet protocol domain of the mobile network (100) and a packet switched access of the mobile network (100) is or is being established for the terminal (108). The method is performed by a control node (104) of the mobile network (100) and comprises receiving (112) a paging request for paging the terminal (108) via the packet switched access. The paging request is for the circuit switched signaling service.

Abstract: A method in an IP multimedia subsystem, IMS, of a telecommunications network. The loss of a secure association between a P-CSCF of the IMS and a user equipment, UE, served by the P-CSCF is detected, or a UE is relocated from a further P-CSCF to the first mentioned P-CSCF. The first mentioned P-CSCF sends a reregistration request to the UE; receives a SIP REGISTER message from the UE; and performs P-CSCF registration with the UE including establishing a new secure association with the UE.

Abstract: A telecommunications network has a packet switched domain for handling packet based calls and a circuit switched telephony domain for handling circuit switched calls. A node of the packet switched telephony domain decides whether to terminate a call to a user equipment using a packet based connection to the user equipment or using a circuit switched connection to the user equipment. In response to deciding to terminate the call using the circuit switched connection, the node sends, to a further node controlling routing of calls between the packet switched telephony domain and the circuit switched telephony domain, an indication that services related to the call are controlled in the packet switched telephony domain. In accordance with the indication, the further node may then adapt its control signalling with respect to a node of the circuit switched telephony domain.

Abstract: A telecommunications network has a packet switched domain for handling packet based calls and a circuit switched telephony domain for handling circuit switched calls. A node of the packet switched telephony domain decides whether to terminate a call to a user equipment using a packet based connection to the user equipment or using a circuit switched connection to the user equipment. In response to deciding to terminate the call using the circuit switched connection, the node sends, to a further node controlling routing of calls between the packet switched telephony domain and the circuit switched telephony domain, an indication that services related to the call are controlled in the packet switched telephony domain. In accordance with the indication, the further node may then adapt its control signalling with respect to a node of the circuit switched telephony domain.

Abstract: One aspect includes a method of operating a user terminal adapted for wireless telecommunications using any of a plurality of different radio access technologies including a Circuit Switched, CS, access and a Packet Switched, PS access. The PS access includes access via a Long Term Evolution, LTE, network and WiFi access via a Wireless Local Area Network, WLAN. The method includes: (i) making a determination to switch from a PS LTE access to a WiFi access, (ii) switching to WiFi access, and (iii) ignoring or rejecting a command received to hand over to a CS access. Other aspects include a user terminal, a telecommunications network entity, and a method of operating a telecommunications network entity.