08 November 2018

Francesco Pasquali, chair of TCCA’s TETRA Industry Group, says TETRA needs connectivity to other bearers, particularly LTE.

The TCCA (TETRA and Critical Communications Association) has set out options for what it describes as the “efficient co-existence” of LMR/PMR/LTE networks.

In its TETRA Connectivity to LTE white paper published in September, the association provides an overview of the different approaches to enabling TETRA/LTE interworking, with several methods described. The key issue addressed is interworking between the LMR/PMR and LTE worlds, particularly the interworking and evolution of PTT services, as group communications capability is the key service in LMR/PMR.

TCCA board member and chair of its TETRA Industry Group, Francesco Pasquali, says TETRA networks are expected to be operational for many years to come. He says: “TETRA will therefore need connectivity to other bearers, particularly LTE, to facilitate long term co-existence, safe migration from TETRA to LTE or as a hybrid communications solution.”

The TCCA says there will be a standard available for interworking between TETRA and LTE that will meet the needs of critical communications users in the 2019 timeframe. But that standard will then need to be converted to products and implemented in LTE networks. The association believes that through using standards-based approaches, users will have the benefit of open competitive markets for their solutions and the ability to use products from different suppliers.

It adds that for those that need solutions now, there is a range of company-specific proprietary solutions that will give various levels of interworking and may in time conform to new standards. 

“The deployed commercial LTE systems deliver very good, but best effort, service until hardened, updated to the latest 3GPP Release, and potentially having their area coverage expanded,” states the TCCA.

3GPP has started standardisation work on the LMR/PMR/LTE interworking functions in Release 15, and the TCCA expects to have this functionality specified in Release 16 which is currently planned for completion by December 2019.

The TCCA goes on to point out that for interworking with another technology, 3GPP can only standardise half of the solution, and work is therefore in progress in ETSI Technical Committee TCCE (TETRA and Critical Communications Evolution) to standardise the equivalent functionality needed by TETRA to achieve a workable solution. 

It says that with there being a “significant” gap between the release of standards and the availability of the associated functionality in products for operational use, it is not expected that there will be a full range of 3GPP compliant interworking solutions deployed until 2021/2022.