Public safety radio system (BOS) - basic principles

Germany’s public safety radio system gives authorities and organisations with safety responsibilities, such as the fire brigade, police, rescue services and Federal Agency for Technical Relief, access to their own nationwide digital radio network based on the Terrestrial Trunked Radio (TETRA) standard. The analogue radio networks that were previously used, with frequency ranges between 70 and 450 megahertz (MHz), have been gradually superseded. Work on building the public safety radio network is now complete.

TETRA was standardised as a professional mobile communications standard by the European Telecommunications Standards Institute (ETSI). It is a digital, cellular mobile trunked radio system for speech and data transmission and is used for the tamper-proof exchange of information within closed user groups. Trunked mobile networks have a similar structure and similar technical data to the GSM networks.

The construction and operation of the network, as well as ensuring its reliability, are the responsibility of the Federal Agency for Public Safety Digital Radio (BDBOS). The network was put into service area by area in a phased process that has now been completed. However, it may be necessary to build further individual base stations in order to adapt the network to current requirements.

Regulations for stationary radio transmitters for the public safety radio network

In Germany, the limit values for emissions from stationary high-frequency installations at locations with an installed radiated power of 10 watts EIRP or more are regulated in the 26th Ordinance Implementing the Federal Immission Control Act (26th BImSchV). The regulations of the 26th BImSchV also apply to stationary installations for the public safety radio network.

In accordance with the Ordinance concerning the Controls of the Limitation of Electromagnetic Fields (BEMFV) of 14 August 2013, a site certificate from the Federal Network Agency is also required for the individual transmitters.

Frequencies and transmitting power

Frequencies between 380 and 395 megahertz are currently available for the public safety digital radio system. Like the GSM mobile communications standard, TETRA uses a time-division multiple access (TDMA) technique, and the signal of the mobile terminal equipment is therefore pulsed (at a pulse frequency of 17.65 hertz). The TETRA standard defines classes of transmitting power for the stationary base stations and the mobile terminal equipment. Accordingly, the base stations have a maximum transmitting power of 40 watts (W) per channel and the mobile base stations have a maximum transmitting power of 30 watts. The transmitting power of the terminal equipment is generally comparable with that of commercial mobile terminal equipment.

Public safety digital radio networks in other European countries

In addition to Germany, there are already 15 other European countries – including Belgium, Denmark, Finland and the United Kingdom – with a nationwide TETRA network, and such networks are currently under construction in other European countries, such as Austria, Italy and Croatia. (Source: BDBOS; as of May 2019).