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TETRA The pan-European trunking standard

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Παρουσίαση με θέμα: "TETRA The pan-European trunking standard"— Μεταγράφημα παρουσίασης:

1 TETRA The pan-European trunking standard
TErrestrial Trunked RAdio

2 Τι είναι το TETRA? Νέο Ευρωπαϊκό Πρότυπο για ραδιοεπικοινωνίες
Καθορίστηκε από το ETSI (1995, 22 Χώρες) Πλήρως Ψηφιακό Επαγγελματικό Σύστημα Κινητών Επικοινωνιών Παρέχει υψηλό βαθμό ασφάλειας και αξιοπιστίας Υποστηρίζεται από πολλούς κατασκευαστές Θα χρησιμοποιηθεί από τις περισσότερες Ευρωπαϊκές χώρες

3 Τι είναι το ETSI? Ευρωπαϊκό Ινστιτούτο Τηλεπικοινωνιακών προτύπων
Παράγει Τηλεπικοινωνιακά πρότυπα για τις χώρες της Ενωμένης Ευρώπης και τις λοιπές δυτικοευρωπαϊκές χώρες Τα πρότυπα του ETSI είναι προαιρετικά για τις χώρες μέλη

4 Οι Διεπαφές του TETRA AIR IF: Ασύρματη διεπαφή
TEI:Διεπαφή Τερματικών συσκευών (ανάπτυξη εφαρμογών data) ISI: Διασύνδεση δικτύων TETRA DMO: Απ’ευθείας σύνδεση τερματικών AIR IF ISI TEI DMO Open interfaces: Controller Gateway BS

5 TETRA Connectivity LAN/WAN Internet 2B+D 30B+D ISDN ISI TEI PSTN PABX
Public Data Network LAN/WAN Internet 2B+D 30B+D ISDN O K C SERV 69 F B ABC TRAFIK 2 STOCKHOLM ISI TEI PSTN PABX Conventional Base Stations Command & Control Systems Trunking Networks Conventional PMR Networks Customer Care & Billing Systems

6 TETRA Voice + Data Services
Man-machine Interface Man-machine Interface TELESERVICES Terminal Interface Terminal Interface BEARER SERVICES Mobile Termination Network Termination Terminal Equipment Terminal Equipment Tetra Network

7 Inter System Interface
Διεπαφές TETRA 1. System air interface 2. Direct mode air interface 3. Man-machine interface 4. Radio data peripheral interface 5. Local dispatcher 6. Gateway to external network 7. Remote line connected terminal 8. Inter system interface 9. Network management interface 2 4 3 1 Base Station Base Station Base Station Network Manager 5 9 Infrastructure Inf. Gateway Controller Inter System Interface 8 Local Dispatcher System Infrastructure 6 7 Remote Line Dispatcher PSTN/ISDN PABX/PDN ISDN

8 Νέα χαρακτηριστικά του TETRA
Πλήρης αμφίδρομη λειτουργία Ταυτόχρονη μετάδοση φωνής και δεδομένων με μια σύνδεση Κρυπτογράφηση δύο επιπέδων: Βασικού επιπέδου στην (ασύρματη διεπαφή); Κρυπτογράφιση απ’άκρη σ’άκρη (end-to-end encryption) ειδικά για χρήστες του τομέα Δημόσιας Ασφάλειας Λειτουργία Ανοικτού Διαύλου (open channel mode) Λειτουργία Παρακολούθησης (dual-watch mode) Υψηλός ρυθμός μετάδοσης δεδομένων

9 Βασικές Υπηρεσίες TETRA
Φωνητικές Υπηρεσίες: Συνήθης κλήση Ομαδική κλήση Ομαδική κλήση με επιβεβαίωση Κλήση τύπου Broadcast Συνήθης ή κρυπτογραφημένη συνδιάλεξη Υπηρεσίες Δεδομένων:Χωρίς προστασία μέχρι 28,8 kBits/s Με προστασία μέχρι 19,2 kBits/s Με μεταγωγή Κυκλώματος (Circuit Switched) Με μεταγωγή Πακέτου (Packet Switched)

10 TETRA Voice + Data Services
Bearer services: Circuit mode data 7.2/14.4/21.6/28.8 kbit/s Circuit mode protected data 4.8/9.6/14.4/19.2 kbit/s Circuit mode heavily protected data 2.4/4.8/7.2/9.6 kbit/s Connection oriented packet data Connectionless packet data Teleservices: Speech for individual call, group call, acknowledged group call, broadcast call Status and short data messages

11 Essential Supplementary Services
Call Authorised by Dispatcher Dispatcher verifies call request before allowing call to proceed. Area Selection Defined areas of operation for users. Can be redefined on a call by call basis. Access Priority Radio Unit uplink access prioritisation during congested periods. Priority Call Access to network resources can be prioritised Late Entry Latecomers may join a call in progress. Pre-emptive Priority Call This call has the highest uplink priority and highest priority access to network resources. If system is busy the lowest priority communication will be dropped to allow this call to continue. Equivalent to an "Emergency Call" in PMR terms. Discrete Listening Authorised RU may monitor a communication without being identified. Ambience Listening Dispatcher may turn on the transmitter of a RU without any indication being provided on RU. Can be used in hijack situations to listen what is happening in the car. Dynamic Group Number Assignment Allows the dispatcher to program new group numbers into the RUs over the air. Can also be used to group participants in an ongoing call.

12 Optional Supplementary Services
Calling Line Identification Present Displays the unit ID of calling party Connected Line Identification Present Displays the unit ID of the called party Calling/Connected Line Identification Restriction Either party may prevent display of unit ID Call Report Displays calling party ID on a busy RU Talking Party Identification RU automatically identifies itself whilst in a group call Call Forward Unconditional Allows an RU to forward all calls to another RU Call Forward on Subscriber Busy Allows an RU to forward calls if RU busy Call Forward on Subscriber Not Reachable Allows an RU to forward calls when out of service or switched off Call Forward on No Reply Allows an RU to forward all unanswered calls List Search Call Incoming call will sequence through a user defined list until call is answered Short Number Addressing Short number dialling Call Waiting Notification of an incoming call to a busy RU Call Hold Allows user to interrupt existing call and re-establish when required Call Completion Busy Subscriber Incoming call will wait until subscriber is free before calling back Call Completion No Reply Incoming call will wait until subscriber has made a call before calling back Transfer of Control Initiator of a group call can transfer ownership to another party Include Call Ability to include an RU in an existing call Advice of charge Call charge information at start, during or end of call Call Barring Ability to bar a call from/to a user defined list Call Retention Ability to prevent call being pre-empted

13 Χρήστες συστημάτων TETRA
Επιχειρήσεις κοινής Ωφέλειας Υπουργεία και Αστυνομία Αγροτικές περιοχές Ιδιωτικές Εταιρείες με μεγάλο στόλο οχημάτων Network operators

14 Τομέας Δημόσιας Υγείας και Ασφάλειας
Αστυνομία (Τελωνεία,, Τροχαία κ.λ.π.) Στρατός Πυροσβεστική και οργανισμοί Διάσωσης Πρώτες Βοήθειες και Ιατρικές υπηρεσίες έκτακτης ανάγκης

15 Τυπικό δίκτυο TETRA για τον Τομέα Δημόσιας Ασφάλειας

16 Υπηρεσίες TETRA για τον Τομέα Δημόσιας Ασφάλειας
Service Dispatcher Clear and ciphered voice PABX/PSTN manual access PABX/PSTN automatic access Image transmission Host database access Radio Local Network (RLN) Computer Aided Despatching Dual watch R.L.N. + + G.P.S. dead Reckoning TETRA Network Automatic + + G.P.S. dead Reckoning PABX PSTN T HOST Digital Map PABX PSTN T + + G.P.S. dead Reckoning Manual Command & Control Centre


Δίκτυα Παροχή Ενέργειας (Αέριο, Πετρέλαιο, Ηλεκτρική Ενέργεια κ.ά.) Μεταφορές (Τραίνα, Στόλοι οχημάτων κ.ά.)

19 Εφαρμογές πελατών Operational Services: Voice Radio Communications with remote areas (extraction wells, booster stations, etc) and Mobile Operators (maintenance and emergency squads, etc). Telephone Communications between peripheral offices, headquarters, and PSTN. Operational Services: Data Efficient Informatic Networks for transmission of data regarding Company’s activities (ex: Energy Production, Treatment Processes, etc.) Administration and Management. Computer applications for production forecast and accounting. On - line tasking and job control.

20 Εφαρμογές (συνέχεια) Operational Services: Remote Control Radio Remote Control of Gas Oil fields, Booster Stations, Oil Treatment Plants, Power Substations, Railways Stations, etc. Telesurveillance for Remote Sites to prevent fires, intrusions and terrorist attacks. Remote metering. Commercial Services: (Service Providing) Voice: - Mobile Communications (Radio Telephony) - Fixed Communications (PABX Network) Data: - Electronic Payment - Others (fax facilities ...)

21 Υπηρεσίες Κέντρου Ελέγχου υποστηριζόμενες από το TETRA
Data acquisition (Gateway towards external Data Banks). GPS SATELLITE models and statistics Satellite Antenna OPERATION MANAGEMENT AND SUPERVISION EXTERNAL DATA BANK Data transfer toward operative locations Data INTERVENTION MANAGEMENT Vehicles localisation TYPE OF ALARM BSC/BCF GPS Satellite Antenna Voice Communications between centre and periphery. CONTROL CENTRE TETRA NETWORK (voice/data) On-board sub-system RADIO OPERATORS EVENT

22 Σύστημα TETRA : Τηλεεπιτήρηση
Remote Video Control of critical areas. Anti-intrusion Systems. Fire-alarm Systems. Access Control.

23 TETRA System: Telesurveillance example CCTV network
M = Optical modulator D = Optical demodulator MI = Management interface CSM = Central system management Remote Area Videocameras M M M M D CENTER Local Control T/R T/R CSM Radio TETRA Network

24 Μονοκυψελωτό σύστημα TETRA

25 Πολυκυψελωτό σύστημα TETRA
System Controller System Controller

26 Ζώνες Συχνοτήτων στην Ευρώπη
380 390 400 383 385 395 393 NATO military use MoU on common frequency allocation has been signed by most European countries Non-NATO countries may allocate military band for civil use (plans for commercial use atleast in Austria and Finland) Plans for civil TETRA networks in MHz band in many European countries (already 2 licences in UK) Other planned frequencies: and / MHz

27 Τεχνικά Χαρακτηριστικά TETRA
Channel Spacing: 25 kHz Modulation: PI/4 DQPSK Channel Data Rate: 36 kBits/s Speech Code Rate: appr. 4,8 kBits/s Access Method: FDMA/TDMA, 4 Timeslots User Data Rate: 7,2 kBits/s per Timeslot Variable Data Rate: 2,4 up to 28,8 kBits/s

28 TDMA Timeslot Channels
"Downlink" Frequency 1 2 3 4 1 2 3 4 1 2 3 4 "Uplink" Frequency 1 2 3 4 1 2 3 4 1 2 3 4 Time Channel = Timeslot sequence (Frequency) 4 Channels per RF carrier occupying 25 kHz Channels may be used for control or traffic Base Station Uplink Downlink

29 TETRA TDMA speech calls use one channel
data calls can use up to 4 channels (multi-slot data)

30 Τεχνικά χαρακτηριστικά TETRA
TDMA Το προσφερόμενο φάσμα χωρίζεται με διαίρεση συχνότητας (FDMA) σε κανάλια με εύρος ζώνης 25KHz το κάθε ένα FDMA f1 f2 Κάθε κανάλι χωρίζεται με διαίρεση χρόνου σε 4 χρονοθυρίδες f3 fn Κάθε χρήστης έχει στη διάθεση του συγκεκριμένη χρονοθυρίδα που είναι χρονικά μετατοπισμένη κατά 2 θυρίδες στην κατερχόμενη ζεύξη

31 TETRA Οικονομική Τεχνολογία
Four-channel TDMA gives excellent spectrum economy - 4 channels in one 25 kHz carrier TDMA makes cost-effective base stations Trunking technology supports controlled use of shared networks

32 TETRA Αξιόπιστη τεχνολογία
Effective priority schemes ensure delivery of important messages Direct mode communications, mobile repeater and gateway functions give added reliability and availability REPEATER DMO GATEWAY

33 Speech Codec & TDMA Frame
A/D ACELP speech coding 4.56 kbit/s Channel 7.2 kbit/s Speech in 4:1 TDMA Frame MUX Gross Bit Rate 36 kbit/s D/A decoding Speech out DEMUX

34 Vocoder Principle Analog Speech 60 ms Framelength Transformation using
a Codebook Samples DA Conversion of Speech Radio Transmisson .

35 Speech Compression "Inbound" Frequency T S 2 T S 3 T S 4 TS 1 T S 2 T S 3 T S 4 TS 1 Speech frame 1 Speech frame 2 Transmitting Radio Micro 60 ms of real speech are coded and compressed for transmission in 14 ms Allows four voice channels to be time multiplexed on carrier frequency

36 Speech Expansion "Outbound" Frequency Receiving Radio Speech frame 1
TS 1 T S 2 T S 3 T S 4 TS 1 T S 2 T S 3 T S 4 Speech frame 1 Speech frame 2 Receiving Radio Laudspeaker 14 ms of digitally coded speech is decoded and expanded back to the original 60 ms analog voice signal

37 TDMA Frame Structure Slow Associated Control CHannel (SACCH).
Hyperframe (61.2s) 1 2 3 4 17 18 508 509 510 5 60 control frame Multiframe (1.02s) TDMA frame (56.67ms) Time slot (14.167ms) = 510 modulating bits Slow Associated Control CHannel (SACCH). Gross bit rate 17 x 510 bits / 1.02 s = 8.5 kbits/s/channel

38 Essential Supplementary Services for Public Safety Application
Call Authorised by Dispatcher CAD Area Selection AS Access Priority AP Priority Call PC Late Entry LE Pre-emptive Priority Call PPC Discreet Listening DL Ambience Listening AL Dynamic Group Number Assignment DGNA

39 Existing TETRA Public Safety Plans
UK Home Office: users from police & fire Germany: users from police & rescue Netherlands Home Office: users from police, fire & ambulance Belgian Home Office: users from police, fire & ambulance Finland: users from police, fire & rescue, border guard + some other offices Austria, Switzerland, Spain, Portugal, Italy, Greece, Sweden, Norway, Hungary, Romania, Estonia, ...

40 TETRA vs. Cellular Systems
Different use requires different tools GSM is excellent system for cellular telephony Professional mobile radio needs appropriate technology O K C SERV 69 F B ABC TRAFIK 2 STOCKHOLM

41 Build PMR by GSM? Technical reasons Direct mode
300 millisecond call setup semi-duplex group communication Cost reasons Only high volumes make cellular phones cheaper compared with professional radios Easier to develop a TETRA system than modify GSM Market strategy reasons Too small volumes for cellular phone industry Too small volumes for GSM infra industry Too risky for GSM operators

42 Spectrum Efficiency TETRA 200kHz bandwidth GSM Half-rate GSM
Traditional PMR 25 kHz PMR 12.5 kHz TETRA 200 kHz carrier 8 channels 16 channels 25 kHz channel 8 channels / 200 kHz 12.5 kHz channels 16 channels / 200 kHz 25 kHz carrier 4 channels / carrier 32 channels / 200 kHz

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