Subject: Mobile Communication and Computing

Topic: Third and Fourth Generation Systems

Difficulty: High

TETRA (Terrestrial Trunked Radio)

Introduction:

1. Trunked radio systems
2. many different radio carriers
3. assign single carrier for a short period to one user/group of users
4. taxi service, fleet management, rescue teams
5. interfaces to public networks, voice and data services
6. very reliable, fast call setup, local operation
7. TETRA - ETSI standard – formerly: Trans European Trunked Radio – point-to-point and point-to-multipoint – encryption (end-to-end, air interface), authentication of devices, users and networks – group call, broadcast, sub-second group-call setup – ad-hoc (“direct mode”), relay and infrastructure networks – call queuing with pre-emptive priorities

Advantages:

1. Very long reach because of up to 20W power emission
2. End-2-End security using strong encryption
3. Direct Mode allows infrastructure free operation
4. Good for fleet-control systems

Disadvantage:

1. Relative old radio approach (standardization started ~1990)
2. Cellular networks have already a full coverage
3. Expensive new infrastructure for emergency service network operators.

Services offered by TETRA

1. Voice+Data(V+D) and Packet Data Optimized (PDO)
2. Short data service (SDS)