IWF Working Group

Interworking Function (IWF) Working Group

The Interworking Function (IWF) is an important consideration for those contemplating operating hybrid mission critical narrowband and mission critical broadband networks and services.

At the crossroads of moving from LMR systems like TETRA, P25 and GSM-R over to the broadband 3GPP world, an interface to facilitate the transition and co-existence between heterogenous systems is needed. TCCA’s IWF Working Group will, in line with TCCA ideology, facilitate between parties a way forward to identify and later develop interworking functions.

The ETSI TETRA and 3GPP broadband IWF specifications are all published and available for download from the websites www.3gpp.org and www.etsi.org

TCCA’s IWF task force has already created and published a TETRA IWF Service Overview, which can be found here.

With these specifications now available, stakeholders and vendors need to come together to determine the optimum solution for the evolution narrowband to broadband networks, using the IWF capabilities.

A white paper authored by the IWF Working Group and published in August 2025: ‘Interworking Function (IWF) Interworking of LMR networks with 3GPP Mission Critical Services’ can be found here.

IWF Working Group Terms of Reference

Contacts:

Michel Duits, Senior Principal Engineer / Product Manager ISI at DSB Norway – michel.duits@dsb.no

Harald Ludwig, TCCA Technical Forum Chair – harald.ludwig@tcca.info

Meetings:

The interworking function (IWF) Working Group was established on 2 December 2024, continuing as a dedicated forum to bring IWF from theory and standards into deployable solutions. The IWF WG is open to all TCCA members that want to work and develop, test and deploy IWF solutions in a community with focus on open standards, verification of standards by testing and support a multivendor domain for mission critical interworking solutions to connect LMR with 3GPP systems.

The IWF WG meets at a regular basis online and meets once per year in person to organise a workshop to discuss and agree on the work streams that are seen as needed in the community.

We have a registered member mailing list to update on meetings and ongoing events inside the WG. With a very practical focus on deployment, an internal goal is to provide a Focus Forum on the status with IWF at TCCA’s annual Critical Communications World event.

If you want to join the IWF WG and stay tuned via the mailing list, joint the team – contact details above.