British Telecommunications Public Limited Company

Alistair Gomez

Ruth Brown

Francisco Faus Gregori

Maria Cuevas Ramirez

A user entity (UE) such as a smartphone is configured to connect to both Wi-Fi and a Long Term Evolution (LTE) cellular network for voice and data services. For voice, the UE supports both Voice over LTE (VoLTE) and Voice over Wi-Fi (VoWiFi). When the UE is connected to VoWiFi and roaming from a first Wi-Fi access point to a second Wi-Fi access point, the UE and Mobility Management Entity in the cellular network carry out a preparatory handover to VoLTE to prevent service loss in the event of an unsuccessful VoWiFi connection from the second Wi-Fi access point.

Voice service handover

A user entity (UE) such as a smartphone is configured to connect to both WiFi and a Long Term Evolution (LTE) cellular network for voice and data services. For voice, the UE supports both Voice over LTE (VoLTE) and Voice over WiFi (VoWiFi). When the UE is connected to VoWiFi and roaming from a first WiFi access point to a second WiFi access point, the UE and Mobility Management Entity in the cellular network carry out a preparatory handover to VoLTE to prevent service loss in the event of an unsuccessful VoWiFi connection from the second WiFi access point.

A wireless access point is configured to regularly monitor the status of WLAN, WAN and ePDG data links to determine whether the current connections are sufficient to support VoWiFI services. When a device connects to the WLAN of the hub and attempts to switch from its VoLTE service to VoWiFi via the hub, the hub is configured to determine whether the current conditions can satisfy a VoWiFi connection. If the VoWiFi service can support the connection, the request is routed to the ePDG associated with the mobile device's subscriber LTE network. However, if the current conditions cannot satisfactorily support a VoWiFi connection such that incoming calls may be missed or the quality of active calls would not be clear, then the hub is configured to block the request so that the client device will time out and remain connected to VoLTE.

Access control to a voice service by a wireless access point

A mobile device capable of connecting to a voice service using Voice over LTE (VoLTE) via a cellular network and Voice over Wi-Fi (VoWiFi) via a wireless local area network is connected to VoWiFi and arranged to receive notifications from a wireless access point when the voice service via VoWiFi is disrupted and to disconnect from VoWiFi and connect to VoLTE to maintain the voice service. The mobile device is operable to test the connection to the cellular network and if the cellular network connection is insufficient to support VoLTE, the mobile device ignored the notification and remains connected to VoWiFi.

Voice service client device

A VoWiFi service monitor monitors the logical data path to the ePDG of a MNO as an indication of whether VoWiFi service is possible for subscribers of the MNO network. Due to the standard configuration of UEs in preferring WLAN connectivity over LTE cellular connectivity, if the VoWiFi service is unavailable the UEs will not automatically switch to VoLTE while a WLAN connection is available between the UE and a hub. When a change in the status of an ePDG is detected, the VoWiFi service monitor informs any connected hubs. The hubs receive notifications from the VoWiFi service monitor and for each notification determine whether the ePDG status change affects one or more of the VoWiFi capable UEs connected to the hub. If at least one such device is affected by the change, the hub notifies the affected UE with instructions to handover from VoWiFi to VoLTE.

Growing community of inventors

London, United Kingdom

Alistair Gomez