TETRA and LTE – fact and fiction – Reposted from Tetra Today
TETRA Today talks to Phil Kidner, chief executive officer of the TCCA, about the part TETRA and LTE technology have to play in the future of critical communications
The annual TETRA World Congress is now known as Critical Communications World, incorporating the TETRA World Congress. The event in Paris this year attracted the highest number of visitors in its 15 year history, due in part to the showcasing of the potential of LTE for public safety broadband applications in the future.
While the future is unknown, the presence of concept applications and devices created much interest, and there were concerns that the focus was shifting from TETRA, which is the dominant mission critical communications technology in the world.
We asked Phil Kidner, chief executive officer of the TETRA & Critical Communications Association, to set out the fact and the fiction regarding mission critical communications.
Are the manufacturers of TETRA switching to LTE?
Some TETRA manufacturers are planning to add LTE capability to their portfolio whilst continuing to fully support TETRA. The development of the TETRA standard continues, with new features, devices, applications and infrastructure, demonstrating TETRA’s continued leading position in the PMR market.
The availability of TEDS for wideband data enables organizations to deploy wideband data services throughout their TETRA networks with the same levels of coverage, security and resilience they already enjoy. TETRA networks already support the majority of applications used by public safety and mission critical users today, and the increasing number of applications is catalysing significant growth in the availability of end-to-end solutions that deliver operational efficiencies to end-user organizations via their existing TETRA network.
So why are the manufacturers promoting LTE?
LTE as a broadband data service will complement TETRA, offering the ability to stream high quality video and transport very large data files. A private LTE service working with TETRA will give users a win-win situation with TETRA as the wide area or nationwide voice and narrowband data service, and LTE available as an overlay to offer broadband data/video services in selected areas as determined by need, finance, and availability of spectrum.
Why not simply use commercially available LTE?
The use of commercial LTE makes sense as an interim capability to carry non-critical and everyday data to enhance operations and efficiency. However, the LTE standards do not currently support any of the services considered vital for critical users, such as for example group working and direct mode. LTE does not provide the coverage, enhanced resilience and security required by mission critical users.
It is important to realize that commercial operators are driven by their business models – they need to generate revenue from the mass market for mobile communications. It is costly and of limited benefit for them to fully replicate the features required by public safety and mission critical users.
In addition, service is imperative for these users in times of emergency or major events, the very times when commercial networks are highly stressed and sometimes have to be limited or even closed down.
What is being done to bring LTE up to scratch for public safety users?
The TCCA and many of its members are working in the standards development organizations, such as 3GPP and ETSI, to lobby for key and fundamentally required additional features to be incorporated into future releases of the LTE standards.
Several releases of the LTE standard will be needed to meet the needs of public safety. It is also not clear yet either whether manufacturers will have the incentive to build new products that incorporate the new features.
If and when the required features for public safety become available over LTE, and are incorporated into commercially available equipment, the TCCA is proposing the use of private LTE systems dedicated to handling broadband data for mission critical and business critical users, working alongside TETRA for mission critical voice services.
Will TETRA eventually be replaced by LTE?
That is up to the manufacturers delivering the technology to meet the users’ demands, but certainly not for a decade or so for the following reasons:
it will take many years for LTE to duplicate the features built up in TETRA over two decades, particularly in such areas as group working, voice, pre-emptive services, network resilience, call set-up times and direct mode;
LTE does not define group communication services so they need to be implemented;
even in commercial LTE networks, voice service is still in the process of being standardised, and is some time away from commercial availability at an acceptable quality; nationwide deployments of either commercial or private LTE will take some time, whilst TETRA is already deployed widely, and continues to be implemented for national networks.