tetra

TETRA, or Terrestrial Trunked Radio, is an ETSI-standardized professional mobile radio (PMR) system designed for mission‑critical communications. It provides secure, reliable voice and data services for public safety agencies, transportation operators, utilities, and other organizations with demanding communications needs.

Technical overview: TETRA uses a TDMA scheme on 25 kHz channels, with four time slots per channel, enabling multiple simultaneous calls within a single channel. It supports private, group, and broadcast voice calls, as well as emergency calls with pre‑emptive priority. Data services include short data messaging and packet data, allowing applications such as status updates, telemetry, and field data. The system emphasizes fast call setup, encryption options, and resilient operation suitable for challenging environments.

Architecture: The TETRA network consists of radio base stations, a core system for call control and mobility management, and interfaces to public or IP networks as needed. The network supports roaming and interworking with other networks through standardized interfaces, facilitating cross-site and cross-border communications. Management and diagnostics tools support deployment, maintenance, and security.

Frequency bands and deployment: TETRA operates in licensed PMR bands, with regional variations often found in VHF or UHF spectra and, in some regions, extended allocations in 700/800 MHz. It has been deployed globally, with widespread use in Europe, the Middle East, Africa, and parts of Asia, notably by police, fire, ambulance services, railways, and utilities.

Evolution: Since its inception in the 1990s, TETRA has evolved through releases that enhanced data capabilities, interworking with IP networks, and overall performance. TETRA remains a cornerstone for mission-critical communications where reliability and security are paramount.