1

2

• Advanced Digital Radio Communications System for

Police, Public Safety Services, Utilities, Transport, Local

Government, Military and these users have contributed

strongly in the creation of the TETRA standard.• Hundreds of networks are operational throughout Europe,

Asia-Pacific, Africa, South America and Middle East • Standard promoted by ETSI• Multi-vendor supply / interoperation

What is TETRA ? TErrestrial Trunked RAdio

3

Milestones in the TETRA standard

• 1990: Standardisation Began• 1995: Standard first phase completed • 1996: Frequency Harmonisation in Europe

(CEPT/NATO) • 1997: Standard Phase II completed• 1998: First systems installation• 2000: 32 TETRA network in 21countries• 2009 100’s of operating networks worldwide

4

5

TETRA – Taking Military Technology to Law Enforcement

6

TETRA - Superior PMR Technology

• Individual and group communications • Direct mode communication between radios “Walkie

Talkie Mode”• Packet data and fast data transfer services• Over-the-air programming of radios (no need for

field personnel to return to station)• Location Based Services• Fast call set-up time, less <330ms which is critical

for police functions• Security features• Ambient Listening (discussed later)

• Military Grade Encryption

7

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.

8

AIR IF

ISI

TEI

DMO

Open interfaces:

Infrastructure (Base Station, Switch, Base Station Controller etc.)

9

TETRA Call Variants – Extremely More Robust Than Any Other Wireless Technology and Uses Military Grade Encryption

10

TETRA TDMA • 4:1 TDMA (Time Division Multiple Access)• 25 kHz carrier spacing• Digital modulation, /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 interleavedinto one 25 kHz carrier

11

WORLD TETRA USAGE

Additionally, many new TETRA networks are being deployed in the Middle East, Asia and new growth isexpected in Africa. TETRA is the “De facto” technologyof choice for law enforcement.

12

TETRA Networks Deployed as of 2008

Note: The same TETRA type of technology is used in the U.S. but is called APCO-25.The U.S. is moving toward using the TETRA standard for law enforcement.

13

TETRA is 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 cost-effective Base Stations

14

TETRA Connectivity Capabilities

TEIOK

C

SERV 69

F BABC

STOCKHOLMTRAFIK 2

ISI

LAN/WAN

PSTN

PABX

Command &ControlSystems

PublicDataNetwork

Internet

ISDN

TrunkedNetworks

ConventionalPMR Networks

ConventionalGSM Networks

Customer Care & Billing Systems

15

TETRA Call Scenarios

• Private call (individual call)– Note: All calls scenarios are encrypted

• Phone call (PSTN or PABX call)

• Group call

• Emergency call (call setup in less than 300 milliseconds)– Any of the above types can be an emergency call– Highest level of call priority, may pre-empt other users based on level of

authority assigned to user– Call type and called party are pre-programmed– Operated by pressing dedicated red emergency button– Broadcast calls

16

TETRA Call – Simplex Calls• Simplex Calls

– Mobile is either transmitting or receiving (Walkie-Talkie Mode)

– Requires operation of PTT switch (Push To Talk)– Talk time is usually limited, typically 1 minute

maximum– Group calls are always simplex

17

TETRA - Duplex Calls• Duplex Calls

– Mobile is transmitting and receiving (like GSM phone call)

– Does not require holding PTT button to continue transmission

18

TETRA - Message Trunking

• A traffic channel is allocated for the duration of the call• Bandwidth is being wasted when no-one is talking • Guaranteed availability and encryption when someone wants to talk

traffic channel traffic channel

Blahblahblah

Blahblahblah

HelloHelloHello

HelloHelloHello

TETRA Base Station

19

TETRA - 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

20

TETRA - Phone call to / from Commercial network• 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

21

TETRA - 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

22

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.

23

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.

24

The Difference between GSM and TETRA SystemGSM System TETRA System

Designed for public / civilian use. Designed for professional mobile radio applications. Military Grade Encryption

Based on Frequency Division Multiplication Access (FDMA)

Based on Time Division Multiplication Access (TDMA) – Economy on frequency spectrum

Not suitable for emergency services (Call set up time ~ a few seconds).

Suitable for emergency services due to very fast call set up time (<300 ms)

Does not maintain privacy and mutual security.

Maintain privacy and mutual security.Ambient Listening Capability – Location Based Services

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.

25

Final Comments

• TETRA is the communications interface with personnel in the field for dissemination of information• A Robust Computer Aided Dispatch System is required for dispatch of field personnel and field management• A Robust Records Management System is required for tracking cases and “people of interest”• TETRA uses enhanced data transmission capability to allow photographs and fingerprints to be checked against databases directly from field personnel's handheld Terminal• Location Based Services tracks field personnel• “Ambient Listening” function allows HQ to discreetly listen to the Terminal, hearing everything the microphone picks up without the user being aware. This is a privileged function.

26

Thank You for Your Attention