TETRA AGA

TETRA Air - Ground - Air services (TETRA AGA) have been developed to provide the same TETRA services to air mobiles as to land mobiles for emergency services. These TETRA services include Mobility Management and all normal TETRA voice and data (V+D) services, but do not include TETRA High Speed Data services (TAPS/TEDS).

TETRA Air - Ground - Air services are delivered by a TETRA AGA overlay network. This AGA overlay network consists of slightly modified TETRA base stations serving modified mobile stations. The modifications are mainly related to cell reselection methods caused by the better propagation conditions between land mobile and air mobile. The other modification is that the TETRA Air - Ground - Air base stations support an extended cell range (radius) of about 83 km.

Based on cells with a range (radius) of 83 km, a seven cell frequency reuse cluster allows for operating heights up to about 3 000 metres. A typical TETRA Air - Ground - Air base station contains only 1 carrier, delivering one control channel and three traffic channels. This capacity is considered to be sufficient for rural areas, villages and average cities. Metropolitan areas and/or airport regions may require more capacity and thus more than one carrier.

The TETRA AGA overlay network has to be accomodated in the 380 - 430 MHz range to allow integration with the existing land based TETRA networks for emergency services. These are typically accomodated in the 380-385/390-395 MHz band.