0
1
Radio Trunking
• Trunking stands for sharing. Whenever resources are in
short supply, they will have to be shared.
• In Ra...
Advantage of Digital Trunking System over Analogue
Trunking System:
• More reliable
• Flexible
• Have connectivity with in...
What is TETRA ? TErrestrial Trunked RAdio
•

Advanced Digital Radio Communications System for
Public Safety Services, Util...
TETRA – The New European Standard for Digital Trunking
TETRA: TErrestrial Trunked Radio
• It is the first truly open digit...
FREQUENCY RANGE:
1. 400 MHz
380 - 400 MHz for public safety systems
410 - 430 MHz for commercial applications
2. 800 MHz f...
Milestones in the TETRA
standard
• 1990:
• 1991:
• 1995:
• 1996:
• 1997:
• 1998:
• 2000:

standardisation start
standard b...
8
TETRA is superior PMR
technology
• Individual and group communications
• Direct mode communication between radios
• Packet...
TETRA Voice + Data Services
• Bearer services:

• Circuit switched mode
• Connection oriented packet data
• Connectionless...
To ensure an open multivendor market, TETRA
specifies the following essential interfaces:
• Air Interface ensure the inter...
Open interfaces:
DMO

AIR IF
TEI

ISI

Infrastructure (Base Station, Switch, Base Station Controller etc.)
12
WORLD USAGE

13
TETRA TDMA
• 4:1 TDMA (Time Division Multiple Access)
• 25 kHz carrier spacing
• Digital modulation, π/4 DQPSK at 36 kbits...
Air Interface - TDMA Illustrated
Hyperframe (61.2s)
1

2

3

4

5

60

Multiframe (1.02s)
1

2

3

4

1

2

17

TDMA frame...
TETRA is the Cost - Effective
Technology
Four-channel TDMA gives
excellent spectrum economy 4 channels in one 25 kHz
carri...
TETRA Connectivity
Public
Data
Network

Internet
2B+D
30B+D

LAN/WAN

ISDN
ISI

SERV
69
STOCKHOLM
TRAFIK 2
F ABC B
O
K
C

...
TETRA call types
• Private call (individual call)
• Phone call (PSTN or PABX call)
• Group call
• Emergency call
– Any of ...
TETRA Traffic case - simplex calls
• Simplex Calls
– Mobile is either transmitting or receiving
– Requires operation of PT...
TETRA Traffic case - duplex calls

• Duplex Calls
– Mobile is transmitting and receiving (like GSM phone
call)
– Does not ...
TETRA Traffic case - Trunking options
• Trunking options only apply to simplex calls
– Applies to private simplex calls an...
TETRA Traffic case - Message trunking
• A traffic channel is allocated for the duration of the call
• Bandwidth is being w...
TETRA Traffic case - Transmission trunking
 A traffic channel is allocated on demand for each ‘over’
 Mobiles return to ...
TETRA Traffic case - Private call
• Private call (individual call)
– A call between 2 parties within the TETRA network
– M...
TETRA Traffic case - Phone call
• Phone call (PSTN or PABX call)
– A call between a TETRA user and a fixed or mobile
phone...
TETRA Traffic case - Group call
• Group call
– A call between more than 2 parties
– Call is always simplex, direct set-up
...
TETRA over IP (ToIP):
• A new development in this field is TETRA over IP (ToIP)
system.
• ToIP system has no central switc...
ADVANTAGES OF TETRA OVER IP
• Future technology: Industry Standard IP Hardware and
Software. Multimedia technology,combini...
Difference between GSM and TETRA System
GSM System

TETRA System

Designed for public cellular
telephony.

Designed for pr...
THANK YOU

30
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  1. 1. 1
  2. 2. Radio Trunking • Trunking stands for sharing. Whenever resources are in short supply, they will have to be shared. • In Radio Telephone Trunking System a fixed number of telephone lines and radio channels are installed in base and are shared by large number of remote/ mobile subscribers. This Radio Telephone Trunking System is commonly known as Radio Trunking System. • First trunked radio standard introduced was analogue MPT 1327 from ROHDE & SCHWARZ 2
  3. 3. Advantage of Digital Trunking System over Analogue Trunking System: • More reliable • Flexible • Have connectivity with internet • Low noise Disadvantages of Digital Trunking System over Analogue Trunking System: • Only disadvantage is that they have low coverage range as compared with Analogue Trunking System 3
  4. 4. What is TETRA ? TErrestrial Trunked RAdio • Advanced Digital Radio Communications System for Public Safety Services, Utilities, Transport, Local Government, Military • Operational throughout Europe, Asia-Pacific, Africa, South America and Middle East • Standard promoted by ETSI • Multi-vendor supply / interoperation 4
  5. 5. TETRA – The New European Standard for Digital Trunking TETRA: TErrestrial Trunked Radio • It is the first truly open digital Private Mobile Radio (PMR) standard. • The standard is defined by the European Telecommunications Standards Institute (ETSI). • The essential parts of the TETRA standard have been approved in national votings at the end of 1995 (22 countries voted for the approval and none against it). • Emergency Service users have contributed strongly in the creation of the standard. 5
  6. 6. FREQUENCY RANGE: 1. 400 MHz 380 - 400 MHz for public safety systems 410 - 430 MHz for commercial applications 2. 800 MHz for commercial applications 6
  7. 7. Milestones in the TETRA standard • 1990: • 1991: • 1995: • 1996: • 1997: • 1998: • 2000: standardisation start standard based on TDMA technology with 4 timeslot and 25 kHz band standard first phase completed frequency armonisation in Europe (CEPT/NATO) standard second phase completed first systems installation presence of 32 TETRA network in 21 countries 7
  8. 8. 8
  9. 9. TETRA is superior PMR technology • Individual and group communications • Direct mode communication between radios • Packet data and fast data transfer services • Over-the-air programming of radios • Frequency economy • Fast call set-up time • Security features • Encryption 9
  10. 10. TETRA Voice + Data Services • Bearer services: • Circuit switched mode • Connection oriented packet data • Connectionless packet data • Teleservices: • Speech for individual call, group call, acknowledged group call, broadcast call • Status and short data messages 10
  11. 11. To ensure an open multivendor market, TETRA specifies the following essential interfaces: • Air Interface ensure the interoperability of terminal equipment from different manufacturers. • Terminal Equipment Interface (TEI) facilitates the independent development of mobile data applications. • Inter-System Interface (ISI) allows the interconnection of TETRA Networks from different manufacturers. • Direct Mode Operation (DMO) guarantees communication between terminals also beyond network coverage (Pl. refer next slide) in event of Base Station failure. 11
  12. 12. Open interfaces: DMO AIR IF TEI ISI Infrastructure (Base Station, Switch, Base Station Controller etc.) 12
  13. 13. WORLD USAGE 13
  14. 14. TETRA TDMA • 4:1 TDMA (Time Division Multiple Access) • 25 kHz carrier spacing • Digital modulation, π/4 DQPSK at 36 kbits/s • Speech calls use one channel • Data calls can use up to 4 channels ( Data transfer rates up to 7.2 kbit/ s per channel) Four user channels interleaved into one 25 kHz carrier 14
  15. 15. Air Interface - TDMA Illustrated Hyperframe (61.2s) 1 2 3 4 5 60 Multiframe (1.02s) 1 2 3 4 1 2 17 TDMA frame (56.67ms) 3 18 control frame 4 Time slot (14.167ms) = 510 modulating bits 1 2 3 4 5 508 15 509 510
  16. 16. TETRA is the Cost - Effective Technology Four-channel TDMA gives excellent spectrum economy 4 channels in one 25 kHz carrier Trunking technology supports controlled use of shared networks TDMA makes costeffective Base Stations 16
  17. 17. TETRA Connectivity Public Data Network Internet 2B+D 30B+D LAN/WAN ISDN ISI SERV 69 STOCKHOLM TRAFIK 2 F ABC B O K C PSTN PABX Conventional Base Stations Command & Control Systems Trunking Networks Conventional PMR Networks Customer Care & Billing Systems 17 TEI
  18. 18. TETRA call types • Private call (individual call) • Phone call (PSTN or PABX call) • Group call • Emergency call – Any of the above types can be an emergency call – Highest level of call priority, may pre-empt other users – Call type and called party are pre-programmed – Operated by pressing dedicated red emergency button – Broadcast calls. 18
  19. 19. TETRA Traffic case - simplex calls • Simplex Calls – Mobile is either transmitting or receiving – Requires operation of PTT switch (Push To Talk) – Talk time is usually limited, typically 1 minute maximum – Group calls are always simplex 19
  20. 20. TETRA Traffic case - duplex calls • Duplex Calls – Mobile is transmitting and receiving (like GSM phone call) – Does not require holding PTT to continue transmission – Recommended for making measurements - no talk timer – Phone calls are usually but not always duplex 20
  21. 21. 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 Above cases explained in subsequent slides 21
  22. 22. TETRA Traffic case - Message trunking • A traffic channel is allocated for the duration of the call • Bandwidth is being wasted when no-one is talking • Guaranteed availability when someone wants to talk Blah Hello blah Hello blah Hello tr a f f ic l anne ch tr a f f i c ch anne TETRA Base Station 22 l Blah Hello blah Hello blah Hello
  23. 23. TETRA Traffic case - Transmission trunking  A traffic channel is allocated on demand for each ‘over’  Mobiles return to the control channel after each ‘over’  Efficient use of bandwidth, channel available for re-use  Channel availability on demand is not guaranteed Hello Hello Hello ic traff l anne ch tr a f f ic ch anne 23 l Hello Hello Hello
  24. 24. TETRA Traffic case - Private call • Private call (individual call) – A call between 2 parties within the TETRA network – May be either simplex or duplex – May be either hook signalling or direct set-up – The mobile may reject or modify some combinations 24
  25. 25. TETRA Traffic case - Phone call • Phone call (PSTN or PABX call) – A call between a TETRA user and a fixed or mobile phone – Call is set up via the TETRA network’s PSTN Gateway – Call is normally duplex, hook signalling – DTMF overdial for end to end signalling 25
  26. 26. TETRA Traffic case - Group call • Group call – A call between more than 2 parties – Call is always simplex, direct set-up – Only possible if one or more groups have been attached 26
  27. 27. TETRA over IP (ToIP): • A new development in this field is TETRA over IP (ToIP) system. • ToIP system has no central switch • It has distributed intelligence at each Radio Site that can process and handle local calls. • Set up inter-site calls and keep track of the registration locations of each subscriber. 27
  28. 28. ADVANTAGES OF TETRA OVER IP • Future technology: Industry Standard IP Hardware and Software. Multimedia technology,combining voice, data and images. Continuous performance improvements driven by IP market. • Efficiency: Call processing is very efficient. • Flexibility: Any combination of Star or Mesh network topology is allowed in order to balance traffic handling •Resilience: Network elements and links can be duplicated for extra resilience. 28
  29. 29. Difference between GSM and TETRA System GSM System TETRA System Designed for public cellular telephony. Designed for professional mobile radio applications. Based on Frequency Division Multiplication Access (FDMA) Based on Time Division Multiplication Access (TDMA) – Economy on frequency spectrum Not suitable for emergency services Suitable for emergency services due (Call set up time ~ a few seconds). to very fast call set up time (300 ms) Do not maintain privacy and mutual security. Maintain privacy and mutual security. Direct Mode Operation(DMO) is not possible. Direct Mode Operation(DMO) is possible, which supports voice and data transmission without a Base Station between Radio Terminals. 29
  30. 30. THANK YOU 30
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