TETRA

TErresterial Trunked RAdio (TETRA) is a digital TDMA system developed to an ETSI (European Telecommunication Standards Institute) standard. TETRA is specifically designed for use by government agencies, emergency services, (police forces, fire departments, ambulance), rail transportation staff, transport services and the military. It offers voice and data communication with data bandwidth on demand and direct mode facility (mobile to mobile). Additionally, Group mobility with Dynamic Groups, Broadcast, Priority and Emergency calls, makes the system ideal for multiple services or organisations sharing the same network.

TETRA provides Authentication Mechanisms of Terminals towards Infrastructure and vice versa. For protection against eavesdropping, over the air encryption and end-to-end encryption is available.

Four channels per carrier are supported, allowing up to 4 simultaneous voice circuits over a simple single-carrier base station (and up to 32 simultaneous voice circuits over our 8-carrier equipment), from any one site.

TETRA is scalable from small to very large systems to cover from single sites up to international networks. Various frequency ranges within the VHF and UHF bands (with the 410-430 MHz band as the standardised range for civil users). Contact us for consultancy on whether your organisation should implement or utilise a TETRA network for your mobile radio applications.

ADVANTAGES

• The much lower frequency used gives longer range, which in turn permits very high levels of geographic coverage with a smaller number of transmitters, thus cutting infrastructure costs.
• High spectral efficiency - 4 channels in 25 kHz and no guard bands, compared to GSM with 8 channels in 200 kHz with guard bands.
• Very fast call set-up - a one to many group call is generally set-up within 0.5 second (typical less than 250 ms for a single node call) compared with the many seconds (typically 7 to 10 s) that are required for a GSM network.
• Works on moving vehicles at high speeds >400 km/h. TETRA was used during the French TGV train speed record on 3 April 2007 at 574.8 km/h.
• The system contains several mechanisms, designed into the protocols and radio parameters, to ensure communication success even during overload situations (e.g. during major public events or disaster situations), thus calls will always get through unlike in cellular systems. The system also supports a range of emergency calling modes.
• The TETRA infrastructure is usually separate from (but connected to) that of the public (mobile) phone networks, resulting in (normally) no call charges for the system owners, substantially more diverse and resilient communications and it is easy to customise and integrate with data applications (vehicle location, GIS databases, dispatch systems, etc.).
• In the absence of a network mobiles/portables can use 'direct mode' whereby they share channels directly (walkie-talkie mode).
• Gateway mode - where a single mobile with connection to the network can act as a relay for other nearby mobiles that are out of range of the infrastructure.
  Equipment is available from many suppliers around the world, thus providing the benefits of competition.

DEDICOM supplies TETRA voice and data systems, from single base stations, including handsets and mobile units, system design and integration, to complete turnkey packages.

Our TETRA infrastructure is based on IP technology, integrating the site controller, base stations, dispatchers, and network management in one state-of-the-art infrastructure. In this way, TETRA equipment supplied by Dedicom integrates easily into EoSDH or MPLS-TP type of fibre-borne networks, which represent another core business activity for DEDICOM.

We can supply scaled solutions, ranging in implementation from a single-carrier complete base station to more complex 8-carrier, rack-mounted equipment. RF units can be tower or mast mounted, reducing cabling costs and losses. Closed internal networks as well as networks with PSTN, ISDN and PDN telephone interconnectivity are supported.