TETRA / TETRA 2

Technology Overview

In practice, the open TETRA standard is a suite of standards covering different technology aspects, e.g. air interfaces, network interfaces and their services and facilities.

TETRA mobile stations (MS) commonly communicate using the radio trunking infrastructure (switching & management infrastructure, SwMI) made of TETRA base stations (TBS). Alternatively, direct communications between mobile terminals are possible in situations where network coverage is not available, e.g. in emergency situations.

The common mode of operation is a group calling mode, immediately connecting the user to selected call groups and/or a dispatcher. Additionally, half- and full-duplex direct connections can be established to other TETRA mobile users or clients in the public and private telephone networks (PSTN and PBX), much like using mobile phones (cell phones).

Access to network resources is automatically managed using multiple priority levels providing different grade of service levels (or tariff structures) to the user, but it also considers emergency calls or pre-emptive priority calls. Several data transmission possibilities as well as the dynamic creation of unique temporary call groups further round out the TETRA service portfolio and are used to handle various communications needs.

TETRA-based products can facilitate built-in encryption features to ensure the privacy and confidentiality of sensitive data and voice communications. Different levels of security are provided by standardized security mechanisms such as authentication, air interface encryption (AIE) and end-to-end encryption (E2EE).

With TETRA Release 2, high-speed data (HSD) enhancements are incorporated, commonly referred to as TETRA enhanced data service (TEDS). Basically, the TEDS specification enhances the throughput capabilities of the TETRA packet data service. Overall, TETRA 2 specifications introduce additional new modulation schemes, channel coding, various coding rates as well as three new channel bandwidths (50 kHz, 100 kHz and 150 kHz) to the standard. TETRA 2 is fully compatible with TETRA Release 1 for ease of migration.

Deployment Scenario

Communications technology conforming to the TETRA standard is tailored for use in what is generally referred to as professional mobile radio (PMR). In this environment, especially for mission-critical applications, the availability and robustness of the technology are of primary importance. Apart from organizations from the public safety sector, the groups of users include those in the fields of transport and traffic (local public transport, railway companies, shipping companies, seaports and airports), military users, utilities (power, oil & gas and water), as well as industrial facilities.

Rohde & Schwarz infrastructure and test solutions

With the digital TETRA trunked radio system – ACCESSNET®-T – Rohde & Schwarz offers a scalable mobile radio solution for all applications in the field of professional mobile radio. Rohde & Schwarz TETRA infrastructure products include the DMX switching unit, which significantly contributes to the performance and reliability of the entire system. Interconnection opens the door to the creation of large nationwide networks.

In the Rohde & Schwarz ACCESSNET®-T mobile radio system, base stations of the DIB series provide air interface resources ensuring wireless communications between subscribers equipped with a TETRA terminal.

The NMS network management system of ACCESSNET®-T is designed for comprehensive network configuration, monitoring of system components and administration of subscriber data.

Rohde & Schwarz also provides dedicated test solutions for TETRA. Standard-conforming signals are easily generated with the R&S^®SMx-K8 software option applicable to the R&S®SMU200A, R&S®SMJ100A and R&S®SMATE200A vector signal generators. Detailed signal analysis is performed with the Rohde & Schwarz signal analyzer family including the R&S®FSU Spectrum Analyzer and the R&S®FSQ Signal Analyzer. The R&S^®FSQ-K70 software option is applicable to TETRA signal analysis, and the R&S^®FS-K110 option enables detailed measurements of TETRA Release 2/TEDS signals.

Key Parameters

Standardization

TETRA is a standard of the European Telecommunications Standards Institute (ETSI); the first version was published in 1995. TETRA 2 was released at the end of 2005. TETRA is endorsed by the European Radio Communications Committee (ERC).