Telecommunication network components configured to manage a pre-establishment phase of a communication session of user equipment are described herein. The components may receive a session-failure indication, e.g., during the pre-establishment phase. The components may determine action data based at least in part on the received session-failure indication. In response to the action data indicating a retry, the components may re-initiate the communication session via an access network indicated in the action data. User equipment may transmit a session-failure indication indicative of a detected failure condition preventing establishment of the communication session.

Telecommunications Network Non-Establishment Response

Telecommunication network components configured to manage a handover of a communication session of user equipment from a packet-switched access network to a circuit-switched access network are described herein. The components may receive a handover request from user equipment, allocate circuit-switched access network resources, and request a session transfer. When the session transfer is invalid, e.g., during a pre-establishment phase of a communication session, the components may reject the transfer within a selected time and provide an invalid-handover message. Components may, in response to an invalid handover request, transmit a rejection of the session transfer and a fallback-trigger message.

Telecommunication network pre-establishment service interruption response

An S-CSCF component within an IMS receives a registration request associated with the UE. The registration request is associated with the UE switching from a first network that provides support for a first feature set to a second network that provides support for the second feature set. Instead of performing registration actions and deregistration actions with an application server in response to the registration request, the S-CSCF compares the feature tags of the registration request with previous feature tags that are associated with currently registered features. The S-CSCF causes a registration action to be performed in response to determining that the current registration request includes a feature tag that is not currently registered. The S-CSCF causes a deregistration action to be performed in response to determining that the current registration request does not include a feature that is currently registered.

Suppressing Third Party Registration and Third Party Deregistration Actions

User equipment communicating with a telecommunications network may be configured to selectively initiate a communication session with another device via a first access network of a first type. During a pre-establishment phase, the user equipment may measure the first access network to provide a first measurement. In response to the first measurement corresponding to a first service-interruption condition, the user equipment may cancel the communication session, tune a radio of the user equipment to communicate with a second access network of a second, different type, and re-initiate the communication session with the other device via the second access network. The user equipment may, after the canceling, receive a retry invitation to the communication session via the second access network, tune the radio thereto, and re-initiate the communication session with the other device via the second access network.

Telecommunication Equipment Measuring Pre-Establishment Service Interruptions

Telecommunications network components configured to manage a handover of a communication session, e.g., an emergency communication session, of user equipment are described herein. A core network device may transmit respective handover queries to a plurality of anchoring network devices following a handover request from user equipment. Each anchoring network device can provide a respective indication of whether the emergency communication session is being proxied by that anchoring network device. The core network device may transmit an invitation message to an anchoring network device in response to a positive indication from that anchoring network device. An anchoring network device may store in a memory an address of the anchoring network device in association with an address of the user equipment. The core network device may retrieve from memory the address of the anchoring network device and transmit an invitation message to the anchoring network device using the retrieved address.

Telecommunications network emergency-call handover

A method of handling the failure of a Service Centralization and Continuity Application Server (SCC-AS) within an IP Multimedia Subsystem (IMS) network implementing a Single Radio Voice Call Continuity function. The method comprises, following the failure of an SCC-AS for a given end user, replacing at an Access Transfer Control Function (ATCF) serving the user, a first Access Transfer Update Session Transfer Identification (ATU-STI) that identifies said SCC-AS, with a further ATU-STI that identifies a redundant SCC-AS. This allows the ATCF to subsequently notify the redundant SCC-AS of an access transfer request in respect of the user.

Johan Roelof Kolner

Papers

Failure handling within a network implementing srvcc