Following the concerns regarding the availability and interoperability of VoLTE emergency calls in both the US and Europe, the GSMA and our members have come together to update and align technical specifications to resolve the issues, which will be available soon.

Acting swiftly, the GSMA board ordered the creation of a new VoLTE Emergency Task Force to address the problem, since it’s a major cause of concern as 2G/3G sunsetting removes the availability of circuit-switched emergency calling (the technology that’s typically used for emergency calling in VoLTE deployed markets).

The new VoLTE Emergency Task Force

Made up of senior representatives from leading Mobile Network Operators (MNOs) covering all regions and collaborating with relevant existing GSMA Network and Terminal Steering Working Groups, the task force began its work in September 2022, and has already agreed on requirements and success criteria for Emergency Calling, VoLTE Interoperability and VoLTE Roaming.

Gaining feedback from device manufacturers

Initially, to gauge the extent of the problem, the GSMA investigated the issues and carried out a poll among UE vendors. The insights showed that devices were a mix of compliant and non-compliant with the 3GPP VoLTE Emergency Call specifications that already exist, which state that VoLTE Emergency Calls are distinct and separate from “normal” VoLTE.

So, a device should always attempt to initiate an emergency call (either via circuit-switch or packet-switch technology, dependent on local network capability) irrespective of whether a normal voice service is available.

Ensuring a smooth transition

Currently, the GSMA Network and Terminal Steering Working Groups are updating the technical specifications that will ensure VoLTE emergency calls are handled correctly in both devices and networks, enabling a smooth transition from circuit-switched to packet-switch-based emergency call support. They are also engaging with GSMA members to align both networks and devices with the specifications.

The GSMA will also continue to support VoLTE interoperability via the promotion of IMS Profile #4 and #6, through the GSMA VoLTE Interoperability Testing service.

VoLTE Roaming should become the default choice for voice roaming. So, MNOs should no longer request device manufacturers to disable IMS when roaming, rather they should enable IMS and allow VoLTE if there is a VoLTE Roaming agreement in place (as indicated by the Voice Over PS Indicator signalled to the UE from the Network).