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INTRODUCTION TO RADIO TRUNKING Digital Radio Trunking Systems – TETRA
What is Radio Trunking ?
Trunking stands for “sharing”.
Whenever resources are in short supply, they will have to be shared.
In Radio Communications Trunking System a fixed number radio frequencies are used and are shared by large number of remote/ mobile subscribers.
The frequency spectrum is a Scare resource.
This is commonly known as Radio Trunking System.
INTRODUCTION TO RADIO TRUNKING Digital Radio Trunking Systems – TETRA
Advantage of Digital Trunking System over Analogue
Trunking System:
More reliable .
Flexible .
Low noise and Provides internet connectivity.
Disadvantages of Digital Trunking System over Analogue
Trunking System:
Only the low coverage range as compared with Analogue Trunking System. This can be overcome by more repeaters.
TETRA -INTRODUCTION
What is TETRA
TETRA stands for “Terrestrial Trunked Radio” initially it is
called as “Trans European Trunked Radio”.
TETRA –New standard from ETSI for digital trunked radio system .
TETRA is the first truly open digital PMR standard.
TETRA standard contains high functionality for Emergency services.
Frequency Range:
380 - 400 MHz for public safety systems,
410 - 430 MHz & 870-876 MHz 915-921MHz for commercial applications
TETRA -INTRODUCTION
Provides individual, group and direct mode communications between radios.
Packet data and fast data transfer services .
Frequency economy.
Fast call set-up time (300 m sec) .
Security features & Encryption .
TETRA provides Voice and Data Services .
Video application in future TETRA-TEDS .
TETRA SPECIFICATIONS
DATA RATES with DIFFERENT PROTECTION LEVELS
TETRA FRAME STRUCTURE.
Four time slot TDMA technology was adopted in TETRA .
One carrier with 25 KHz spacing provides 4 channels using TDMA (Time Division Multiple Access) .
TETRA FRAME STRUCTURE.TDMA Structure of the voice + data system
TETRA FRAME STRUCTURE.BIT RATE OF TETRA SYSTEM
1 Time Slot =510 modulating bits duration=255 symbols
TETRA –SPECTRUM EFFICIENCYCOMPARISION WITH OTHER STANDARDS
TETRA CALL TYPES
TETRA call types
Private call (individual call) .
Phone call (PSTN or PABX call).
Group call .
Emergency call .
Broadcast call .
TETRA Traffic case - Trunking options
Trunking options only apply to simplex calls .
Applies to private simplex calls and group calls .
Trunking type is controlled by the Base Station.
Message Trunking .
Transmission Trunking .
What about commercial digital networks?GSM / CDMA 2000
Public mobile networks do not fulfil all public safety requirements.
Public mobile networks are developed to meet the demands of consumers, which are very different from those of public safety organisations.
It cannot guarantee service during emergencies and disasters.
It cannot provide FAST call set-up time(<300 m sec).
It cannot provide special terminal functionality .
Difference between GSM and TETRA System
Divisions in INDIA using TETRA radio system
The DELHI Metro project.
The HYDERABAD police .
The Delhi Airport.
INDIAN Parliament.
Digital Radio Trunking Systems – TETRA Summary
In order to tackle terrorism, all the user agencies of Govt. and Private Organizations need to upgrade and integrate their communication infrastructure for secure, faster & reliable communications.
This integrated network should be capable of providing unified command and control channels for voice, data and video applications in future.
Digital Radio Trunking Systems – TETRA Summary
Disasters – both natural and man-made .
Major Incidents/ fires .
Incidents .
RTA (Road Traffic Accidents) .
Routine policing .
CONCLUSION
TETRA is emergent digital PMR technology.
Characteristics like consistent voice quality, greater call privacy , fast call set-up ,high speed data transfer and outstanding spectral efficiency etc .reflects the dominance of TETRA over other PMR and PAMR systems.
It is modern technology for police ,fire service ,military ,etc.
Future success of TETRA depends on network operators to deliver benefits of TETRA services cost effectively to end users.