TETRA has evolved from slow-speed data in its first release and integrates wideband data / TEDS today. TEDS gives higher data rates with up to several hundred kbit/s and very well fits into existing PMR frequency landscape.

The TETRA standard fulfills all important requirements of mission critical communications. It addresses Public Safety organisations, but TETRA is also the primary standard for private organisations needing a radio system with integrated voice and data capability.

The integration of broadband technologies in TETRA is the next big technological step and will provide even higher data rates than with TETRA and TEDS today. Even the transmission of high resolution video can be realized with today's broadband technologies.

Today LTE already became the dominant standard for broadband data communication in public mobile radio business and is already accepted as the standard for the future evolution of TETRA. LTE is a data pipe where all kind of services are realized on top in a service oriented architecture. Similar to TEDS, LTE provides a packet data channel and delivers feature rich multimedia applications to end user devices.

Drivers for broadband PMR

Especially public safety organizations but also utility and transport companies are asking for multimedia data applications in order to optimize their day-to-day operations.

The IP based broadband data service is basis for all kinds of mobile data applications which increase productivity. In a public safety scenario broadband helps to increase the situational awareness of an officer in the field or at the command center.

Similar to the public mobile radio industry, "apps" will also enter the PMR segment and are the basis to develop customer tailored tools which support day-to-day operations.

What is specific about Mission Critical Communications?

PMR specific services (group call, status messages,...) and a high level of security and privacy are essential to satisfy the daily business demands of TETRA users today. PMR networks require highest network and service availability, therefore redundancies and stand alone modes are standard. Even in case the network infrastructure is not available, direct peer-to-peer communication between end-user devices has to be supported.

This means that public networks can only be used for applications which are non mission critical. Technologies intended for public use have to be adapted and modified to satisfy PMR users and operators. Especially the end user equipment has to be robust, fit for purpose and built for intensive use.

Spectrum situation

lthough wideband and broadband systems are typically using advanced and adaptive channel coding techniques, higher data rates go hand in hand with the need of more RF spectrum. As LTE currently does not fit into existing PMR frequency bands and requires at least 2 x 10 MHz to provide reasonable performance in typical public safety scenarios, new spectrum has to be found and allocated. The USA selected 700 MHz LTE primarily for mission critical data applications for public safety organizations.

Other regions not yet decided on the frequency bands for broadband PMR, but it is likely that they will also follow and allocate channels in the 700 MHz band.

Why not use public networks?

Public Safety networks have a high demand on network availability, especially in times of disaster. Public network operator optimise their investments based on the expected revenue. Especially radio coverage is planned in areas which have a high user density.

In contrast to public networks, PMR networks have to provide a high degree of radio coverage. Network security is an important topic as well, especially for public safety organisations which typically need full network control and as reliable communication as possible.

Hytera's broadband vision

Hytera Mobilfunk GmbH has more than 30 years of experience in the development of PMR systems and base station equipment. The extremely reliable and robust TETRA system ACCESSNET-T IP fits very well to the different application scenarios of our customers. The ACCESSNET-T IP core consists of computing platforms that provide PMR features to the network and radio users as well as all kinds of interfaces to other networks and applications. ACCESSNET-T IP also provides the necessary tools for system and radio terminal management.

Similar to TEDS, LTE is an additional radio access which fully integrates into the ACCESSNET-T IP core network. Especially data-centric services are delivered over LTE. In many cases broadband will be used as an overlay network to supplement the narrowband system with higher data rates where seamless mobility between different radio accesses is ensured.