68P66500U01-D Sect1_Intro_R3_0
Short Description
Download 68P66500U01-D Sect1_Intro_R3_0...
Description
Compact TETRA Section 1 Introduction and System Overview
68P66500U01-D
Issue Sept 2004
Intentionally Blank
Issue Sept 2004
Contents 1.
Introduction
1.1. 1.2. 1.3.
What is TETRA? Compact TETRA Design Concept System Elements
2.
System Overview
2.1. 2.2. 2.3.
System Elements Interfaces Actors
3.
System Components
3.1. 3.1.1. 3.2.
Base Station CTS100/200/300 Base station details System Equipment
4.
Call Features
4.1. 4.2. 4.3. 4.4. 4.5. 4.6.
Speech Services Data Services Short Data Service (Type 1 - Status) Short Data Service (Type 4 – Text Messages) Packet Data Service Voice Call Capabilities
5.
System Configurations
5.1. 5.2. 5.3. 5.4.
Basic configurations Stand-alone System Single-Site System Multi-Site System
6.
Resilience
6-1
7.
The System Signalling Path
7-1
7.1. 7.2. 7.3. 7.3.1. 7.3.2. 7.3.3. 7.3.4. 7.4. 7.5. 7.6.
Overview Radio Air Interface Software Applications OSI Layers The system Voice Path MS/BS Air Interface Protocol (DLL – Layer 2) Overview of the CSCIs on the Base Station. Transceiver Base Station Controller The Gateway PC.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page: Nr. 6866500U01-D Author: Bryan Simcock
1-1 1-1 1-1 1-2
2-1 2-1 2-2 2-3
3-1 3-1 3-2 3-6
4-1 4-1 4-1 4-1 4-1 4-2 4-2
5-1 5-1 5-1 5-2 5-4
7-1 7-1 7-2 7-2 7-3 7-4 7-5 7-5 7-6 7-6
C-1
7.6.1. 7.6.2. 7.6.3. 7.7. 7.7.1. 7.7.2. 7.8. 7.9. 7.9.1. 7.9.2. 7.9.3. 7.9.4. 7.9.5. 7.9.6. 7.9.7. 7.9.8. 7.9.9. 7.9.10. 7.9.11. 7.9.12. 7.10. 7.11. 7.12. 7.13. 7.14. 7.15. 7.16. 7.16.1. 7.16.2. 7.16.3. 7.16.4. 7.16.5. 7.16.6. 7.17. 7.18. 7.19. 7.20. 7.21. 7.22. 7.23. 7.24. 7.25. 7.25.1. 7.25.2. 7.25.3. 7.26. 7.27. 7.28. 7.29. 7.30.
The Structure of the Gateway PC Functions of the Gateway PC. Gateway Computer Software Configuration Items (CSCIs) Dispatcher Work Station The following diagram shows the structure of the Gateway PC The CSCIs on the Dispatcher Workstation Tetra Air Interface Layer 2 – Overview Tetra Air Interface Layer 3 – Overview Base Site Link Entity (BLE) Circuit Mode Control Entity (CMCE-L) Air-Interface Resource Manager (AIRM) Mobility Management (MM-L) Packet Data (SNDCP-L) U-Plane Switching (USWITCH) Distributed Application – Overview Circuit-Mode Control Entity (CMCE-U) Mobility Management (MM-U) Dynamic Data Distribution (DD) Packet Data Handling (SNDCP-U) Subscriber Profile and Configuration Data Distribution (SPCDD ) Tetra Codecs PABX/PSTN Gateway (ISDNGW) Packet Data Gateway (PDG) Registration of a Mobile/Dispatcher Deregistration of a Mobile/Dispatcher Call Set-up Procedure Inter-Site Call Set-up Calls Originating at the PABX/PSTN Gateway Calls Terminating at the PABX/PSTN Gateway Calls Originating at a Dispatcher Calls Terminating at a Dispatcher Call Restoration Multi Site Call Restoration – Group Call Pre-emptive Priority Call CLIP and TPI Subscriber Data Management Short Data Service (SDS) Packet Data Logging and Tracing System Start-up GPS Interface BSC-Transceiver Interface The Clock Interface. The PCM Highway. The HDLC bus. Inter-Site Interface U-plane Communication Signalling Communication Management Communication Dispatcher Interface (DA-IF)
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page: Nr. 6866500U01-D Author: Bryan Simcock
7-6 7-7 7-7 7-8 7-8 7-9 7-9 7-10 7-10 7-10 7-11 7-12 7-12 7-12 7-12 7-14 7-14 7-15 7-15 7-15 7-16 7-16 7-16 7-17 7-17 7-17 7-18 7-18 7-19 7-19 7-19 7-19 7-20 7-21 7-21 7-21 7-21 7-22 7-22 7-22 7-23 7-23 7-23 7-23 7-23 7-24 7-24 7-24 7-25 7-25
C-2
7.31. 7.32.
BSC Ethernet Interface BSC RS232 Interface
7-25 7-25
8.
Accessing the BSC Locally
8-1
8.1.
Frequency Configuration
9.
Dispatcher Workstation CTD-1
9.1.
Dispatcher operation
10.
Gateway Server CTG-1
10.1. 10.1.1. 10.2.
The NMS.cfg Configuration File The NMS.cfg File Network Management Configuration (NMA)
11.
Packet Data Gateway
11-1
12.
Connecting a Server to the Packet Data Gateway
12-1
12.1. 12.2.
Gateway LAN (Server) Port At the Server:
13.
Connecting a PC to a Radio
13-1
13.1. 13.2. 13.3. 13.4.
PC Configuration Dial-Up Connection Settings Accessing a Server via a Radio/PC Connection Setting Up The Packet Data Connection
13-1 13-6 13-15 13-15
14.
Account Management
14-1
14.1. 14.2. 14.3. 14.4.
Feature Description (Single and Multi-Site) System configuration overview System parameters and specification Base Station Specification
15.
Radio (MS – Mobile Subscriber) Registration
15.1.
Mobile De-registering
16.
Call Release
16-1
17.
Reasons for Call failure
17-1
18.
Group Attachment / Detachment
18-1
19.
Transmission Control
19-1
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page: Nr. 6866500U01-D Author: Bryan Simcock
8-1
9-1 9-1
10-1 10-2 10-3 10-4
12-1 12-1
14-2 14-3 14-4 14-5
15-1 15-1
C-3
20.
Call Restoration
20-1
21.
Pre-emptive Priority Call
21-1
22.
CLIP and TPI
22-1
23.
Failure of a Traffic Transceiver
23-1
24.
Failure of the MCCH Transceiver
24-1
25.
Failure of Base Station Controller (BSC)
25-1
26.
The Tetra Air Interface
26-1
27.
Time Division Multiplexed Radio Carriers
27-1
27.1. 27.2. 27.3. 27.4. 27.5. 27.6. 27.7.
Slot Structure Control Channel Traffic Channel Unallocated Channel Single Slot Full Duplex Operation Multi Slot Full Duplex Operation Single Slot Semi Duplex
28.
Uplink Time Slot Structure
28.1. 28.2. 28.3.
The Control Uplink Burst The Linearisation Up link Burst Normal Uplink Burst
29.
Downlink Time Slot Structure
29.1. 29.2. 29.3. 29.4. 29.5. 29.6. 29.7. 29.8. 29.9. 29.10.
The Normal Continuous Downlink Burst The Synchronisation Continuous Downlink Burst Burst Mode Power Ramping The Normal Discontinuous Downlink Burst The Synchronisation Discontinuous Downlink Burst The Linearisation Downlink Burst The Normal Training Sequence Phase Adjustment Bits Synchronisation Training Sequence The Broadcast Block
30.
Transmission Power Levels
30.1.
Mobile Station (MS) Output Power Levels
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page: Nr. 6866500U01-D Author: Bryan Simcock
27-1 27-3 27-3 27-3 27-4 27-4 27-4
28-1 28-1 28-2 28-2
29-1 29-1 29-2 29-2 29-3 29-4 29-4 29-4 29-5 29-5 29-5
30-1 30-1
C-4
30.2.
Base station Output Power Levels
31.
Communication Channels
31.1. 31.2. 31.3. 31.4. 31.5. 31.6.
Traffic Channel Assignment The Broadcast Control Channel The Linearisation Channel The Signalling Channel The Access Assignment Channel The Stealing Channel
32.
Control Channel Assignment
32.1. 32.2. 32.3.
Control Channels The Common Control Channel The Dedicated Control Channel
33.
Traffic Control
33-1
34.
Mobility Management
34-1
34.1. 34.2. 34.2.1. 34.2.2. 34.2.3. 34.3. 34.4. 34.4.1. 34.4.2. 34.4.3. 34.4.4. 34.5. 34.5.1. 34.5.2. 34.5.3.
Cell Acquisition at Power Up Channel Selection RSSI - RxLev_Access_Min = > 0 Radio Improvable Radio Relinquishable. Cell Optimisation Acquiring an Adjacent Cell C2 – Radio Improvable C2 – Radio Relinquishable C2 - Radio Usable *Typical System Settings for Cell Coverage MS Actions at Cell Reselection Announced Unannounced Undeclared
35.
Miscellaneous
35.1.
Ethernet 10/100Base-T Straight Through Cable.
36.
Interoperability Test for Compact TETRA
36-1
37.
Motorola Terminals used for Compact TETRA
37-1
38.
Glossary of terms and abbreviations
38-1
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page: Nr. 6866500U01-D Author: Bryan Simcock
30-2
31-1 31-1 31-2 31-2 31-2 31-2 31-2
32-1 32-1 32-1 32-2
34-1 34-1 34-2 34-2 34-2 34-3 34-3 34-4 34-5 34-5 34-5 34-6 34-6 34-7 34-7
35-1 35-1
C-5
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page: Nr. 6866500U01-D Author: Bryan Simcock
C-6
1.
Introduction This system overview explains the Motorola solution for a compact trunked radio system conforming to the European ETSI - TETRA standard. Compact TETRA provides speech and data communication and suits a wide range of users.
1.1.
What is TETRA? Terrestrial Trunked Radio (TETRA) is the modern digital Private Mobile Radio (PMR) and Public Access Mobile Radio (PAMR) technology for police, security services, military, public access, fleet management, transport services, closed user groups, business and industry services etc. TETRA offers fast call set-up time, addressing the critical needs of many user segments, excellent group communication support, direct mode operation between radios, sophisticated data services, full duplex communication, frequency economy and excellent security features. TETRA uses Time Division Multiple Access (TDMA) technology with 4 user channels on one radio carrier and 25kHz spacing between carriers. This makes it inherently efficient in the way that it uses the frequency spectrum.
1.2.
Compact TETRA Design Concept Compact TETRA is a new design using distributed intelligence and latest state-of-the-art technology. The system provides a high degree of resilience through inherently distributed architecture. It can tolerate the failure of individual components and links without employing expensive centralized redundancy concepts. Equipment failures have only a limited effect on system operation; should a transceiver fail, another one will take over the operation. The switching intelligence is distributed across the sites without the need of a central controller. Should one site fail or be interrupted the system will continue to operate with the remaining sites. This system behavior is called graceful degradation. The system uses digital voice coding throughout the network. This results in the best possible end-to-end voice quality and the fastest possible call set up times. The system also operates in multi-site configurations. In the maximum network configuration, the system provides 128 simultaneous channels and supports up to 8 sites. Compact TETRA is easy to set up and to configure. Extensive monitoring and control facilities ease initial system set-up and reduce cost of ownership. Online monitoring functions and extensive logging and tracking facilities are also offered. Applications Specific Interfaces (API’s) such as the Packet Data and Short Data Service Gateway and the Peripheral Equipment Interface allow a wide range of customer specific applications.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:1-1 Nr.: 6866500U01-D Author: Bryan Simcock
1.3.
System Elements Transceiver - this handles one Tetra AI carrier and is composed of one frequency pair, the Uplink and Downlink. Base Station – this is a single Tetra cell and it can have up to 8 transceivers, 1 Base Station Controller (or 2 to meet redundancy requirements), an antenna subsystem with associated supporting infrastructure including racks, PSUs etc. Gateway PC - this is the interface between the tetra network, dispatchers and external networks such as PABX/PSTN and other external data networks. It is responsible for voice transcoding and the inter working at upper network layers and also fulfil the rolls for both system and subscriber management, allowing: •
The viewing and the updating of the static and dynamic system data.
The monitoring and maintenance of the system Dispatcher Workstation - this is a specially equipped multi functional PC that primarily enables the dispatcher to co-ordinate mobile users and also has the capability to:
•
•
Monitor and participate in multiple group activities.
•
Have both voice and SDS access to the network.
The workstation can also fulfil the rolls for both system and subscriber management, allowing: •
The viewing and the updating of the static and dynamic system data.
•
The monitoring and maintenance of the system.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:1-2 Nr.: 6866500U01-D Author: Bryan Simcock
2.
System Overview The following figure (Fig. 2-1) shows the system components and their interfaces. The circle indicates the system boundary. Objects within the circle are part of the distributed system (some of them are optional). The objects outside the circle are not part of the system and are referred to as ACTORS (see paragraph 2.3). Double-ended arrows denote logical interfaces whereas physical interfaces are indicated by straight connections between the objects. Interfaces that cross the system boundaries are open and committed to the customer or approved application partner.
Fig. 2-1:
2.1.
Real World Object Model and System Interfaces
System Elements ●
Base Station (BS): Handles a single TETRA cell and all layers of the TETRA AI. The BS consists of up to 8 transceivers, one BS Controller, an antenna subsystem, and supporting infrastructure (racks, power supply, etc.)
●
Transceiver: Handles one TETRA AI carrier consisting of a frequency pair (uplink / downlink).
●
Gateway Server: (Not part of the stand-alone system) is the interface between the TETRA network, external networks (PABX/PSTN and data networks), and Dispatchers. It is responsible for the voice transcoding and interworking at upper network layers.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:2-1 Nr.: 6866500U01-D Author: Bryan Simcock
From the internal network point of view, the gateway server is just an additional node in the E1 ring.
2.2.
●
Dispatcher Workstation: (Not part of the stand-alone system) Is a specially equipped workstation that primarily serves the dispatcher user in cocoordinating mobile users. It provides extended capabilities to: ● Monitor and participate in up to 5 group activities ● Support voice and SDS access to the TETRA network ● Provide access to the system management and subscriber management application ● Allow viewing and updating of system static data ● Provide system monitoring and maintenance applications
●
Stand-alone Configuration PC: This is any standard PC using MS Netmeeting that provides access to the stand-alone system management and subscriber management interfaces.
Interfaces ●
Air Interface: TETRA standard air interface
●
E1 link:
●
Dispatcher Workstation Interface: (Not part of the stand-alone system) The Dispatchers are connected to the Gateway Server via 100Mbps Ethernet links. There must be a Switch in case more than one workstations are connected.
●
Configuration Interface: Is a logical interface that provides the ability to change the system parameters and static subscriber data.
●
Monitoring Interface: (Not fully supported by the stand-alone system) Is a logical interface that provides monitoring of the system status and its sub-elements.
●
Logging and Tracing Interface: Is a logical interface on the Gateway Server which provides log files with the following information about the system usage: ● Call logs, listing calling and called party with timestamp and call duration ● Mobility logs, listing the movements of mobiles ● SDS (Short Data Service) logs, listing a sender and a receiver with the timestamp for user defined messages ● Debug logs, listing system information
Compact TETRA COPYRIGHT Motorola 2002
(Not part of the stand-alone system) Each BS can be connected to 1 or 2 other BS or the Gateway Server via 2Mbits E1 links. The topology used is either ring or a daisy chain. The structure within the E1 links is proprietary to the system.
Intro & System Overview R3_0.doc Page:2-2 Nr.: 6866500U01-D Author: Bryan Simcock
2.3.
●
Dispatcher User Interface: (Not part of the stand-alone system) Is the HMI (Human Machine Interface), with which the dispatcher interacts. It displays the actual status of selected ongoing calls, the messages addressed to the dispatcher, etc. It allows the dispatcher to communicate with the system.
●
Packet Data Interface: This interface provides IP (Internet Protocol) connectivity between the mobiles and an external IP network with access to several external applications.
●
SDS Transport Service Interface: (Not part of the stand-alone system) This interface provides SDS transport to/from mobiles from/to an external server via a TCP connection.
●
PSTN/PABX Interface: (Not part of the stand-alone system) This interface links the TETRA network to a public (PSTN) or private (PABX) telephone network. It allows for individual voice calls between the TETRA network subscribers and external subscribers.
Actors ●
Terminal:
●
Dispatcher: A person using the dispatcher workstation. The dispatcher primarily co-ordinates the mobile users.
●
External subscriber: Anybody who connects to the system via the Gateway PSTN/PABX interface.
●
Maintenance staff: Configures the system parameters, maintains the hardware elements, installs new hardware and software, and performs the second level trouble-shooting.
●
Operator:
●
Packet Data Application: This application uses the system as an IP sub-network to route IP traffic to/from a mobile application.
Compact TETRA COPYRIGHT Motorola 2002
Ordinary TETRA mobile radio or portable radio, which connects to the system over an air interface (AI). It can be used for voice communications, sending status or text SDS messages, or connecting a data application to the system.
A person who collects information about the system status/performance and usage, and performs the first level trouble shooting.
Intro & System Overview R3_0.doc Page:2-3 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:2-4 Nr.: 6866500U01-D Author: Bryan Simcock
3.
System Components
3.1.
Base Station CTS100/200/300 The Compact TETRA base station comprises all necessary hardware and software to control the entire site. The base station includes: Base station controller including switching SW • Interface to the E1 network • Receiver/Transmitter including amplifier and combiner • Power supply The base station sites are linked together through 2Mbps E1 connections in a ring or ‘open ring’ topology. •
The Base Station Controller (BSC) handles all functions related to the operation of the base station and the switching. The BSC also provides internal clocks for time and frequency synchronization. The BSC is equipped with its own crystal oscillator and with a GPS receiver. The synchronization priority will be set in the order: GPS, E1 reference, internal clock. Accurate time base is needed for synchronization in Multisite Systems only. The BSC is driven by a Pentium Processor, which controls the TETRA protocol, the subscriber database, the network management and all multi-site switching functionality. The base stations provide the following features: TX output power 25W TETRA (10W after combiner) • Freq. bands 380-400, 410-430, 450-470 MHz, 806-870MHz • Dual Receiver Diversity • Optional Redundant Base Station Controller (BSC) • Advanced remote diagnostics down to module level • Tower Mounted Amplifier (TMA) to save feeder costs • Redundant Power Supplies 110/230VAC and –48VDC. • Antenna Combiners and filters Alarm functions for all Base Stations •
Alarm circuits will supervise all major Base Station circuits. 8 ext. alarm inputs are available from which one is dedicated to the door alarm. All alarms will be forwarded to Dispatcher PC. Antennas for the Base Stations Each base station requires one TX antenna plus one or two RX antennas. The Intelligent Dual Receiver Diversity increases the coverage of the system. Duplexers are not recommended when using several transceivers due to the risk of generating intermodulation. One GPS Antenna per Base Station Controller is required for the synchronization of the Base Stations in Multi-site systems.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:3-1 Nr.: 6866500U01-D Author: Bryan Simcock
3.1.1.
Base station details Three generic base station configurations are available for Compact TETRA. The selection should be made depending on the traffic prediction and the requirements for future channel upgrades. CTS100 - Compact base station with up to 8 channels Tower Mounted Amplifier (TMA) Same Frequency band As Transmitter Filter
2 GPS Antenna Connectors
Remove Cover to access Junction Box
N Type Tx Antenna Connector
AI411 Dual Receiver Multi Coupler Base Station Controller
Battery Unit
Transmitter Filter
2 Transceivers Cooling Fan Tray & LED Indicators Power Supply
Hybrid Combiner
CTS 100 • • • • • • • • • • • • •
Compact TETRA COPYRIGHT Motorola 2002
1 or 2 TETRA-Carriers/Transceivers 8 HU version AC/DC power supply including Battery charge Optional built-in backup battery, 48V/7Ah Optional redundant AC/DC power supply Hybrid Combiner Base Station Controller BSC Optional redundant BSC Tower Mounted Amplifier (TMA), external GPS receiver built-in for synchronization Measures (HxWxD): 476,6x542x520 Weight: 47 kg (fully equipped) Power Consumption: 280 Watts (fully equipped)
Intro & System Overview R3_0.doc Page:3-2 Nr.: 6866500U01-D Author: Bryan Simcock
CTS200 - Compact base station with up to 16 channels.
Note: The TMA is mounted by the antennas.
Antenna Connector Types Tx - ‘7/16 Din’ Tx Rx - ‘N’ Type GPS - BNC
Transmitter Filter TF413 behind rear panel
Junction Box behind Door
Dual Receiver Multi Coupler Base Station Controller
4 Transceivers
RF Test Loop Combiner
Power Supplies
Cooling Fan Tray With LED Indicators
CTS200 • • • • • • • • • • • • •
Compact TETRA COPYRIGHT Motorola 2002
1-4 TETRA-Carriers/Transceivers 22 HU version AC/DC power supply including external battery charge Terminal for external backup battery Optional redundant AC/DC power supply 1 Cavity Combiner (Hybrid Combiner optional) Base Station Controller BSC Optional redundant BSC Tower Mounted Amplifier (TMA), external GPS receiver built-in for synchronization Measures (HxWxD): 1054x542x520 Weight: 97 kg (fully equipped) Power Consumption: 512 Watts (fully equipped)
Intro & System Overview R3_0.doc Page:3-3 Nr.: 6866500U01-D Author: Bryan Simcock
CTS300 - Compact base station with up to 32 channels Note: TMA is mounted by the antennas. Junction Box behind Door
Antenna Connector Types Tx - ‘7/16 Din’ Tx Rx - ‘N’ Type GPS - BNC
Dual Receiver Multi Coupler
8 Transceivers Transmitter Filter Behind rear panel
RF Test Loop Combiner Power Supplies
Cooling Fan Tray with LED Indicators
CTS300 • • • • • • • • •
Compact TETRA COPYRIGHT Motorola 2002
1-8 TETRA-Carriers/Transceivers 37 HU version AC/DC power supply Terminal for external backup battery Optional redundant AC/DC power supply 1 or 2 Cavity Combiners (1 for 4 carriers each) 1 Base Station Controller BSC Optional redundant BSC Tower Mounted Amplifier (TMA), external
Intro & System Overview R3_0.doc Page:3-4 Nr.: 6866500U01-D Author: Bryan Simcock
• • • •
Compact TETRA COPYRIGHT Motorola 2002
GPS receiver built in for synchronization Measures (HxWxD): 1720x542x520 Weight: 147 kg (fully equipped) Power Consumption: 975 Watts (fully equipped)
Intro & System Overview R3_0.doc Page:3-5 Nr.: 6866500U01-D Author: Bryan Simcock
3.2.
System Equipment Equipment
TS100
CTS200
CTS300
Transceiver
4
8
8
Base Station Controller
1
1
1
Base Station Controller (redundant)
1
1
1
Power Supply with Rectifier
1
1+
1+
External Battery Kit
1
1
1
TR Cassette for BS
1
1
1
PS Cassette for BS
1
1
1
Ant. Interface
1
1
1
Tower Mounted Amp.
1
1
1
Hybrid Combiner
1
1 (Optional)
Tx Filter
1
Dual 4/8-way divider
1
1
1
1
1
4 or 4-8 way TX Combiner
1
1
TX Combiner kit 4 or 4-8 ch
1
1
TF411 TX Filter 25dB
1
1
RFTL Combiner Tower Mounted Amp.
Connection Box for 1-2 x BSC
1
1
1
Gateway PC
1
1
1
Gateway PC + Switch (Redundant)
1
1
1
Central Recording Equipment
1
1
1
1 to 8
1 to 8
1 to 8
Tx
‘N’ Type’
‘7/16 Din’ Tx
‘7/16 Din’ Tx
Rx
‘N’ Type
‘N’ Type
Dispatcher Console Antenna Connectors
‘N’ Type
Note: A configuration may have from 1 to 8 carriers per site, 1 or 2 BSCs, and 1 to 5 PSUs and dependant on the type of CTS, the number of carriers and whether or not redundancy is ordered.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:3-6 Nr.: 6866500U01-D Author: Bryan Simcock
4.
Call Features Compact TETRA provides a wide range of call features, which enables a large number of user groups intelligent and efficient ways to communicate. The call features can be subdivided into speech calls (individual calls, group calls, telephone) and data calls (status, short data, packet data).
4.1.
Speech Services The users have a fast and efficient way of communicating with each other while maintaining full privacy. Individual Call Half-duplex call for short precise messages ● Full-duplex call for high quality and comfortable telephony-type calls Group Call ●
Allows the users to communicate with team members spread among the coverage area with fast call set up and late entry facility Pre-emptive Emergency Group Call ●
●
4.2.
Initiated by the subscriber – a pre-emptive function clears a channel with lower priority in case all traffic channels are too busy to operate an emergency call
Data Services This provides the users with a means to get “operational” applications into the field as well as a means to send precise messages between users. The feature allows fast and efficient communication when there is little time to talk. Typical applications are: Text Messaging, Automatic Vehicle Location (AVL), Automatic Vehicle Monitoring (AVM), Short Dispatch Messages, Database enquiries, Telemetry, Fleet Management.
4.3.
Short Data Service (Type 1 - Status) ●
●
4.4.
Allows the user to transmit pre-defined individual status messages, even if subscribers are engaged in a speech call Provides for up to 250 status messages (also depends on subscribers)
Short Data Service (Type 4 – Text Messages) ●
●
Allows the user to transmit and receive text messages, even if subscribers are engaged in a speech call Up to 140 characters can be transferred in one message (also depends on subscribers)
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:4-1 Nr.: 6866500U01-D Author: Bryan Simcock
4.5.
Packet Data Service ●
4.6.
With IP-based Packet Data a mobile user can be permanently connected to a central database or the Internet
Voice Call Capabilities Terminal-to-Terminal call: Full duplex individual call • Half duplex individual call • Group Call including Late Entry feature • Short Data Service (Status and Text up to 140 Characters) • Packet Data Calls Terminal to Dispatcher call: •
Full duplex individual call • Half duplex individual call • Group Call including Late Entry feature • Short Data Service (Status and Text up to 140 Characters) Dispatcher to Terminal call: •
Full duplex individual call Half duplex individual call • Group Call including Late Entry feature • Short Data Service (Status and Text up to 140 Characters) Dispatcher-to-Dispatcher call: • •
Full duplex individual call • Half duplex individual call • Group Call including Late Entry feature • Short Data Service (Status and Text up to 140 Characters) Dispatcher to Telephone call: •
Full duplex individual call Terminal to Telephone call (PABX or PSTN): •
Full duplex individual call Telephone to Terminal call •
Full duplex individual call with Direct-Dialing-In feature Telephone to Dispatcher call •
Full duplex individual call All calls directed to terminals will be queued in case of busy resources (transceivers). Calls from terminals to telephone subscribers will be blocked if all telephone lines are busy. •
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:4-2 Nr.: 6866500U01-D Author: Bryan Simcock
5.
System Configurations
5.1.
Basic configurations The system is flexible and extendible and supports the following basic configurations:
5.2.
•
Stand-alone system (without telephone interconnect, without external Packet Data and Short Data interconnect and without dispatcher)
•
Single site system with up to 32 channels, 8 or 30 ISDN channels and a maximum of 8 Dispatchers supporting up to 2.500 subscribers
•
Multi site network with up to 8 sites, up to 128 channels, 8 or 30 ISDN lines and a max. of 8 Dispatchers supporting up to 10.000 subscribers
Stand-alone System The Stand-alone system configuration is focused on customer groups needing local coverage without dispatch functionality and gateways. It supports Individual and Group Calls as well as Short Data and Packet Data Services among subscribers. The Stand-alone Compact TETRA can be configured by means of a standard PC connected to the Base Station Controller (BSC). For online monitoring of the system status and load conditions, the PC needs to be permanently attached to the system. Because this system configuration requires no supporting infrastructure or networking other than power supply and the antenna, this configuration is most suitable for transportable and quick installable applications.
Stand-alone System
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:5-1 Nr.: 6866500U01-D Author: Bryan Simcock
The stand alone system can be either of the 3 types of base station, CTS100,200 or 300, with: •
Up to 8 Transceivers giving 32 virtual channels
•
2,500 Subscriber radios in 256 Groups
•
A redundant BSC
•
Redundant power supplies
•
Battery charging capabilities
It has no connectivity to the outside world (ISDN or Packet Data Gateway).
5.3.
Single-Site System Besides the Basestation the single site system provides a Gateway Server with the following interfaces: ●
Interface to PABX/PSTN following the Euro-ISDN standard for up to 8 full duplex individual speech calls (4xISDN)
●
Interface to external customer IP network for Packet Data and Short Data Service.
●
Interface to connect up to 8 Dispatcher Workstations Dispatcher Workstations with On-line monitoring, control of system status and health and subscriber management user interface. The single-site system is targeted primarily at customers who need local TETRA coverage and additionally dispatch functionality and/or gateways. The connection between the Site and the Gateway is a single fractional E1 link. The connections to the Dispatcher Workstations or the IP-networks require 100Mbps Ethernet LAN infrastructure.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:5-2 Nr.: 6866500U01-D Author: Bryan Simcock
Single –site System The single site system can be either of the 3 types of base station and it can have: • Up to 8 Transceivers giving 32 virtual channels •
2,500 Subscriber radios in 256 Groups.
•
A redundant BSC
•
Redundant power supplies
•
Battery charging capabilities
The system has a Gateway PC (GWPC) that provides connectivity to the outside world via an ISDN Gateway for Telephone links and a Packet Data Gateway for data linking. The Gateway acts as the master node of the system for: All data base files, subscriber management etc. All base stations check their files against the GWPC files on power up. Up to 8 Dispatcher consoles may be connected to the Gateway PC via a switch with the equivalent (or better) specification to that of the HP Procurve Switch 2512
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:5-3 Nr.: 6866500U01-D Author: Bryan Simcock
5.4.
Multi-Site System The Multi-site system offers all of the features of the single-site system with, additionally, multi-site individual and group calls, including call restoration of all individual and group calls (seamless handover from one site to another one). An intelligent paging strategy conserves air interface resources yet ensures that subscribers may be reached for group communications at all sites. Subscribers are only attached to group calls at Basestations where at least one subscriber of the called group is registered. The multi-site system supports up to 10,000 subscribers. The system tracks the location and group attachment status of the registered subscribers in a distributed database that allows fast local access to the information on call set-up. The multi-site system uses a chain of E1 links to interconnect the sites and the Gateway Server. When the chain is closed (ring configuration) a break of a single link would not cause any communication error. For reduced cost of ownership, smaller system configurations can use fractional E1 using multiplexers. The system can be configured to limit the E1 time-slots used for communication to a certain range.
Multi-site System
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:5-4 Nr.: 6866500U01-D Author: Bryan Simcock
This has the features of the single site system and can have up to a further 7 base stations giving a maximum total of 32 Transceivers that give 128 virtual channels, supporting 10,000 Subscriber radios in 256 Groups.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:5-5 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:5-6 Nr.: 6866500U01-D Author: Bryan Simcock
6.
Resilience Distributed intelligence Because of the de-centralized structure of the entire system and the distributed intelligence, the basic TETRA features can be performed on each site independently. This allows local site fallback in the case of failures in the infrastructure. All sites can work in local trunking mode without gateway and dispatchers. Redundant power supplies and Base Station Controller The site can be equipped with redundant power supplies and a redundant Base Station Controller (BSC). In the case of a failure of the operational BSC all ongoing calls will be lost but the stand-by controller will take over and start operating without the need of reconfiguration. Inter site links The chain of base stations can be either open, or closed with one additional E1 link. This additional link affords system fault-tolerance against single link failures; if one of the links fails, all system services will continue unimpaired. Even in the open-chain configuration, the multi-site system performs graceful degradation in the case of link failures. If the network is partitioned, each of the sub-networks will continue to function and allow unhindered communication between all subscribers in the sub-network. The speech transmission will be interrupted for a maximum of 1 second during switchover. E1-Ring-Configuration:System capabilities, parameters and specifications
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:6-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:6-2 Nr.: 6866500U01-D Author: Bryan Simcock
7.
The System Signalling Path This section explains the following:
7.1.
●
The OSI protocol layer structure of the system.
●
The interaction of the different layers.
●
The sub divisions, where appropriate, of each layer.
●
The functionality of the different protocols running on each layer.
●
Where, on the system hardware, these layers/protocols sit.
Overview The hardware construction is based on the transceiver and Base Station Controller. The Cells and Gateway are linked through 2Mbit E1 connections in a ring or linear topology with drop and insert functionality. Sub-rated (fractional) E1 can be used to scale the number of E1 channels required for the size of the system. The ring topology can offer a high grade of redundancy if routing is provided in both directions. The gateway is used for system connection to PABX/PSTN/IP network(s) and for dispatcher console connectivity to the system and supports the following functions: ●
Network Management
●
Subscriber Management
A dispatcher console may support the following functions:
7.2.
●
Dispatcher
●
Network Management
●
Subscriber Management
Radio Air Interface This consists of the transceivers and the antenna combining system. The transceivers have an output power of up to 25W Tetra, giving approximately 10W Tetra after combining. The antenna branching system contains the following: ●
A cavity or hybrid combiner.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-1 Nr.: 6866500U01-D Author: Bryan Simcock
●
Tx filter.
●
Antenna interface.
●
Rx filtering.
●
Tower Mounted Amplifier (TMA). The Hybrid combiner is only used for combining 2 transceivers (Carriers), if more carriers are used, then a cavity combiner is used. Note: Only the system designed combiners can be used, no other combiner has the capability to work with the system and give the same functionality.
7.3.
Software Applications The OSI layers are software applications running on the system that inter re-act. The receive information from one application (a lower layer), is passed to a higher layer application. The application may action the information and pass it back to the previous layer, or it can pass the information on to the layer ‘above’ and/or to its peer at another node.
7.3.1.
OSI Layers End User B
End User A
Higher Level Protocols
Application Layer Presentation Layer
Application Layer End User Functions
Session Layer
Session Layer
Transport Layer
Network Services
Transport Layer
Network Layer Data Link Layer
Presentation Layer
Network Functions
Physical Layer
7
Layer Number
6 5 4
Network Layer
3
Data Link Layer
2
Physical Layer
1
Physical Medium
The OSI model showing its 7 functional layers, is now accepted for description and specification of layered communication architectures. The bottom 3 layers of the protocol stack are associated with the network services and have to be implemented in every node of the network, both infrastructure and MS.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-2 Nr.: 6866500U01-D Author: Bryan Simcock
The upper 4 layers of the protocol stack provide services to the end users and are thus associated with end users, not the network. The philosophy of layered architecture is based on each layer being independently specified in terms of the services it provides to its immediately higher level and the services it relies on from its immediately lower level. The Layer architecture provides ‘Peer to Peer’ exchanges, in which each layer exchanges information with its peer entity at the remote end. Note: The Tetra Standard defines the network protocol only up to layer 3.
7.3.2.
The system Voice Path
Transceiver
Transceiver A1
MAC
Transceiver
MAC
MAC A1
A1
8KbitsTetra Coded Head Set E1
E1
E1 Loud Speaker Mic
8Kbits/s Tetra Coded in E1 Time Slots Gateway PC E1 Card
Pentium H.100
Pentium
VoIP VoIP
ISDN Card
DSP Tetra Codec
G711
Compact TETRA COPYRIGHT Motorola 2002
Ethernet Card
Packetised G711 Over PCI
Ethernet Card
Analogue I/O
Packetised G711
Dispatcher PC
Intro & System Overview R3_0.doc Page:7-3 Nr.: 6866500U01-D Author: Bryan Simcock
7.3.3.
MS/BS Air Interface Protocol (DLL – Layer 2) C-Plane (Control Plane)
U-Plane (User Plane)
MM
PD
CMCE
Layer 3 MLE – Mobile/Base Link Control Entity
LLC – Logic Link Control Layer 2
MAC – Medium Access Control
Layer 1
Physical Layer
C-Plane Traffic: MM Mobility Management – Controls roaming, migration and handover. CMCE Circuit Mode Control Entity – CC – call control, – SS – supplementary services & short data service (SDS). PD Packet Data - CONS – connection oriented network service CLNS – connectionless network service Note: MM, CMCE & PD are collectively called Sub-network access functions (SNAFS) U-Plane Traffic: Responsible for: Clear/encrypted speech, Circuit mode unprotected data, Circuit mode protected data (low), Circuit mode protected data (high), End to end user specific data.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-4 Nr.: 6866500U01-D Author: Bryan Simcock
7.3.4.
Overview of the CSCIs on the Base Station. Distributed Application (Site)
SPCDD D B
Message Router MM-U
SNDCP -U
CMCE-U
To other sites and GWPC
AI L3
U SWITCH A I R M
MM-L
CMCEL
SNDCPL
BLE
AI L2
LLC MAC
7.4.
Transceiver The transceiver handles one Tetra air interface carrier, i.e., one uplink and one downlink frequency. It handles all layers of the Tetra air interface up to and including the upper MAC. It is responsible for: Routing of Tetra U-plane traffic between the Air Interface and the PCM Highway leading to the BSC. Routing of Tetra C-plane traffic between the Air Interface and the HDLC bus leading to the BSC. Handling of modulation and synchronisation for receiving and transmitting over the radio interface
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-5 Nr.: 6866500U01-D Author: Bryan Simcock
7.5.
Base Station Controller The functions of the BSC are: ●
Control the transceivers of the Base Station
●
Handle all layers of the Tetra air interface from LLC upwards
●
Switches the PCM sub-timeslots between the internal communication paths to/from the transceivers and the external E1 links.
●
Alarm reporting
●
Operations and Maintenance
Communicate with other base station controllers and the Gateway PC for the following purposes: ●
Inter-site call control
●
Distribution of global status information about the status of the nodes in the distributed application
●
Distribution of subscriber-related static data (subscriber profiles)
●
Distribution of subscriber-related dynamic data (current registration status and location of subscribers).
7.6.
The Gateway PC.
7.6.1.
The Structure of the Gateway PC
Inter-Site Links
H.100 Bus
E1 Card
DSP Card
PSTN/PABX Gateway Dispatcher LAN
PDG
ISDN Card
Ethernet Card
Ethernet Card
PCI BUS Compact TETRA COPYRIGHT Motorola 2002
Pentium Motherboard Windows NT
Hard Disk
CD ROM
Intro & System Overview R3_0.doc Page:7-6 Nr.: 6866500U01-D Author: Bryan Simcock
7.6.2.
Functions of the Gateway PC. It contains commercial off-the-shelf (COTS) components and is the:
7.6.3.
●
Speech gateway for the inter working between TETRA speech calls and an external telephone network. Two types of gateway are available: ● A 4-fold ISDN-BR gateway offering 8 simultaneous speech calls over four Euro Isdn basic rate links. ● An ISDN Primary Rate gateway offering 30 simultaneous speech calls over a G.703 2048kbit/s link.
●
Packet data gateway for the inter working between TETRA SNDCP packet data and an external IP-based network.
●
Dispatcher Gateway for the connection of Dispatcher Workstations.
●
Tetra Codecs for PABX/PSTN and Dispatchers
●
Operations and Maintenance Server
●
Subscriber Management Server
Gateway Computer Software Configuration Items (CSCIs) Distributed Application (Gateway PC)
SPCDD
D B
E1 Message Router
CMCE-U
To Sites
U-SWITCH
DA-IF
Codecs
OMSA
Switch
SMSA
canceller
DISPS
To Dispatcher Work Stations
Compact TETRA COPYRIGHT Motorola 2002
SNDCPU
ISDNGW
To PSTN or PABX
MMU
PDG
To External IP Network
Intro & System Overview R3_0.doc Page:7-7 Nr.: 6866500U01-D Author: Bryan Simcock
7.7.
Dispatcher Work Station The Dispatcher Workstation HWCI is a standard PC containing commercial offthe-shelf (COTS) components and provides the human interface to the Tetra system. The following applications are accessed at this PC: ●
The dispatcher client application that allows dispatchers to set up and receive calls, and send and receive SDS.
●
The Operations & Maintenance client application that allows users to monitor and control the operation of the system.
●
The Subscriber Management client application that allows users to manage the subscriber data base of the system. The Dispatcher Workstation uses a standard headset connected at the sound card (PC SoundBlaster compatible).
7.7.1.
The following diagram shows the structure of the Gateway PC
MIC Headset
Sound Card
Loudspeaker Dispatcher LAN
Ethernet Card
PCI BUS
Pentium Motherboard Windows NT Hard Disk
Compact TETRA COPYRIGHT Motorola 2002
CD ROM
Intro & System Overview R3_0.doc Page:7-8 Nr.: 6866500U01-D Author: Bryan Simcock
7.7.2.
The CSCIs on the Dispatcher Workstation
Dispatcher WS
OMCA
HMI SMCA
DISPC
To Dispatcher Work Stations
7.8.
Tetra Air Interface Layer 2 – Overview The Tetra Air Interface Layer 2 consists of the MAC CSCI and the LLC CSU. MAC ●
The MAC SW is running on the transceiver cards and handles the lower layers of the Tetra Air Interface Layer 2.
LLC ●
The LLC is running on the BSC HWCI as part of the AI CSCI.
●
The LLC handles the upper layer of the Tetra Air Interface Layer 2.
●
It provides basic the link for CMCE, MM, and SNDCP signalling and the advanced link for SNDCP data transmission.
Compact TETRA
Intro & System Overview R3_0.doc Page:7-9 Nr.: 6866500U01-D Author: Bryan Simcock
COPYRIGHT Motorola 2002
7.9.
Tetra Air Interface Layer 3 – Overview The Tetra Air Interface Layer 3 consist of the BLE, the CMCE-L, the AIRM, the MM-L and the SNDCP-L CSUs. Together with the LLC CSU, they make up the AI CSCI. Structure of Tetra Air Interface Layer 3
Distributed Application
AI Layer 3
MM-L
CMCEL
SNDCP -L
AIRM
BLE
LLC
7.9.1.
7.9.2.
Base Site Link Entity (BLE) ●
The BLE is running on the BSC HWCI and is the SwMI-side counterpart of the MLE in the MS.
●
It routes messages between the LLC and the other Layer 3 entities, and it handles the MLE protocol.
Circuit Mode Control Entity (CMCE-L) The CMCE-L CSU is running on the BSC HWCI as part of the AI CSCI and is the SwMI-side counterpart of the CMCE in the MS. It handles the protocol for circuitmode calls and SDS transmissions. Its main responsibilities are: ●
PDU encoding and decoding
●
Protocol timer handling
●
Interaction with the AIRM for air interface resource management
●
Mediation between the air interface and the CMCE-U.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-10 Nr.: 6866500U01-D Author: Bryan Simcock
It cooperates with the Air Interface Resource Manager (AIRM) to allocate and deallocate air interface channels and queues calls when these resources are not immediately available. It passes all uplink call signalling to the higher layers and is not concerned with: ●
The routing of calls or the decisions as to whether or not a call may proceed.
●
Call log generation. For downlink call signalling, all call setup requests are received from CMCE-U and there is no “shortcut” for single-site calls. For SDS transmissions, it converts the uplink PDUs to internal primitives and passes them on to CMCE-U and it converts the downlink primitives to downlink PDUs.
7.9.3.
Air-Interface Resource Manager (AIRM) The AIRM CSU is running on the BSC HWCI as part of the AI CSCI. It handles the allocation and de-allocation of both Traffic Channels (TCH) and Packet Data Channels (PDCH) and is responsible for the: ●
Air Interface Stack start up and shutdown.
●
Allocation and de-allocation of TCH on behalf of CMCE-L.
●
Allocation and de-allocation of PDCH on behalf of SNDCP-L.
●
Queue management for as-of-yet unfulfilled requests for resources by CMCE.
●
Management of transceiver failures.
For single-site semi-duplex individual calls, it is responsible for merging the allocation requests of the independent CMCE-L entities into a single channel allocation and for this purpose, the AIRM keeps a reference count for each allocated TCH and de-allocates the TCH only when the last reference goes away.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-11 Nr.: 6866500U01-D Author: Bryan Simcock
7.9.4.
Mobility Management (MM-L) The MM-L CSU is running on the BSC HWCI as part of the AI CSCI and is the SwMI counterpart of the MM in the MS. It handles the protocol for registrations, de-registrations, and group management and its main responsibilities are: ●
PDU encoding and decoding
●
Mediation between the air interface and the MM-U It is a stateless protocol converter that sends and receives all uplink/downlink signalling to/from the MM-U.
7.9.5.
Packet Data (SNDCP-L) The SNDCP-L CSU is running on the BSC HWCI. It handles the Tetra SNDCP protocol and passes context activation and deactivation commands to the SNDCP-U. It routes datagrams between BLE and SNDCP-U and manages AI resources for Packet Data channels.
7.9.6.
U-Plane Switching (USWITCH) The U-Plane switch runs on the Base Sites and Gateway PC. On the inter-site links, Tetra speech is transmitted in 8kbit/s channels. On the LAN, to the Dispatchers, speech is transmitted via IP and on the speech gateway, speech is transmitted in G.711 format The channels on the inter-site links are always present on all nodes of the system. The U-Plane switch is a software layer that can locally switch speech channels and has the following functionality: It hides the details of the physical implementation of the switch, which is different on the sites and the Gateway PC. It handles re-switching of speech connections when a system component fails.
7.9.7.
Distributed Application – Overview The distributed application consists of a number of CSUs, each of which is responsible for one group of functions. There is one instance of the distributed application running on each site and Gateway PC. The peer instances communicate with each other using the inter-site communication protocol. The distributed application also contains two databases:
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-12 Nr.: 6866500U01-D Author: Bryan Simcock
●
The global static subscriber data base (GSDB) holds the static subscriber profile.
●
Each node holds one copy.
●
The GSDB is only updated by subscriber management actions.
●
The global dynamic subscriber data base (GDDB) holds the dynamic subscriber information, i.e., location information and group attachment status.
●
It is updated dynamically by user actions (roaming, registration, deregistration, and group management actions). Structure of Distributed Application
Distributed Control, Management &
r
CMCE-U
GSDB
w
SPCDD
MM-U w GDDB r SNDCP-U
AI Layer 3 / PSTN/PABX GW / Dispatcher Server
Compact TETRA COPYRIGHT Motorola 2002
Inter-site Communication
Intro & System Overview R3_0.doc Page:7-13 Nr.: 6866500U01-D Author: Bryan Simcock
7.9.8.
Circuit-Mode Control Entity (CMCE-U) The CMCE-U runs on the Sites and on the Gateway PC and it handles the protocol-independent aspects of the Tetra CMCE functionality. On the sites, it cooperates with the Air Interface Layer 3, and on the Gateway PC, it cooperates with the PABX/PSTN Gateway and the Dispatcher Server application. It communicates with its peer entities in other nodes via the Inter-site communication layer. For calls originating on the local node, it is responsible for: ●
Call validation.
●
Location lookup.
●
Routing of the call setup signalling to one or several remote nodes, and/or to one or several local protocol stacks (CMCE-L, DISP-GW, PABX/PSTNGW).
●
Handling of call duration timers and call inactivity timers (for semi-duplex calls).
For calls terminating at the local node, it is responsible for: ●
routing the call setup signalling to one or more local protocol stacks.
In either case, the CMCE-U is responsible for: ●
Mediation between the local protocol stacks and the peer entities for call maintenance procedures.
●
Generation of call logs.
●
Failure management.
If a network node fails or becomes unreachable, each CMCE-U instance is responsible for locally disconnecting all ongoing individual calls with that node.
7.9.9.
Mobility Management (MM-U) The MM-U runs on the Sites and on the Gateway PC and is responsible for the protocol-independent aspects of the Tetra MM functionality. It acts as a server for the local protocol stacks. During mobility management requests on the local site, MM-U is responsible for the following: ●
Validating the request and rejecting it if the validation fails
●
Updating the local copy of the dynamic subscriber data base
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-14 Nr.: 6866500U01-D Author: Bryan Simcock
●
7.9.10.
Triggering the transmission of the updated information to all peer entities for registration and deregistration requests.
Dynamic Data Distribution (DD) The DD is responsible for maintaining a global up-to-date and consistent view about the location of the subscribers in the face of user actions and system component failures. The peer entities of the DD communicate with each other via Inter-site communication layer. If a node becomes connected again after being disconnected, or after a reboot, the DD is responsible for synchronising the state of the dynamic subscriber data with the global state. For requests coming in from a local stack, the DD is responsible for distributing the information to its peers. For requests coming in from a peer entity, the DD is responsible for updating the local copy of the dynamic subscriber data.
7.9.11.
Packet Data Handling (SNDCP-U) The SNDCP-U CSU is running on the Sites and on the Gateway PC and is responsible for the transmission of Tetra packet data among sites, and between the sites and the packet data gateway. It sits on top of SNDCP-L on the sites, and on top of the packet data gateway in the Gateway PC. On reception of a datagram from the lower protocol (SNDCP-L in the case of the site, the Packet Data Gateway in the case of the Gateway PC), the SNDCP-U CSU looks at the destination IP address. If the net mask indicates that the datagram is for a Tetra subscriber, SNDCP-U looks up the SSI of the destination subscriber, otherwise, it uses the Packet Data Gateway SSI. On reception of a datagram from another node, it checks whether the subscriber is reachable on the node. ●
If not, it sends back an ICMP “Host unreachable message”.
●
If yes, it passes the datagram to the lower protocol stack.
Tetra packet data is transferred through the system as signalling data, not as standard IP traffic.
7.9.12.
Subscriber Profile and Configuration Data Distribution (SPCDD ) This is running on the Sites and on the Gateway PC and it consists of a server application running on the Gateway PC and of client applications running as part of the distributed application. It handles the distribution of the following: ●
Subscriber profiles.
●
Static configuration data.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-15 Nr.: 6866500U01-D Author: Bryan Simcock
●
Software updates. All static configuration data is kept in files containing a timestamp and version number and all master copies are kept on the Gateway PC. The distribution server keeps a record of the file version that should be on each of the sites and if the version of a file changes on the Gateway PC, it is distributed to the clients. On reception of an updated configuration file (e.g. for subscriber profiles), the clients DD reads the new version of the file into internal data structures and switches over to the new version of the configuration data. If a site becomes connected again after being disconnected and after a reboot, the local SPCDD instance will send a message to the distribution server to notify it of its local current versions of all configuration files. The server will then inform the site of any new versions of configuration files that have been created in the meanwhile.
7.10.
Tetra Codecs The Tetra Codecs are implemented on DSPs in the Gateway PC The Tetra Codecs convert speech between the 8kbit/s Tetra encoded format and 64kbit/s G.711 (A-law) encoded format.
7.11.
PABX/PSTN Gateway (ISDNGW) The ISDN Gateway is a feature of the Gateway PC and it enables the inter working of individual full-duplex speech calls between the Tetra System and either a PABX or the ISDN. It has the following main responsibilities:
7.12.
●
Inter working of Basic Call signalling between the ISDN and the Tetra system
●
Control of U-Plane transcoding and switching
●
Employment of echo cancellation to attenuate the reflected echo from the PABX/ISDN. This is needed as a result of the speech delay introduced in the Tetra system imposing more stringent requirements for attenuation of echoes.
Packet Data Gateway (PDG) The PDG is a feature of the Gateway PC and it enables the inter working of IPv4 between the Tetra System and an external IP network. The Tetra network appears as one Class B subnet to the IP network. Within the system the packets are routed using the mobility information of the mobiles. The packets are transported via the signalling interface between the sites. All packets with external IP addresses are routed to the Gateway. The translation between internal packet representation and IP is done at the Gateway.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-16 Nr.: 6866500U01-D Author: Bryan Simcock
7.13.
Registration of a Mobile/Dispatcher Registration of a mobile at a site is handled locally by the site and triggers an update of the distributed dynamic subscriber databases. For the registration of a mobile to the local site, the main operational steps map to the CSCIs as follows: ●
The MM-L receives a U-LOCATION UPDATE DEMAND PDU from the BLE and signals the registration to MM-U.
●
The MM-U consults the local copy of the static subscriber data base to check the permission of the subscriber to register.
●
The MM-U updates the local copy of the dynamic subscriber database, sends an update request to all peer entities and creates a log entry.
●
The MM-U acknowledges the registration to MM-L.
●
The MM-L then sends a D-LOCATION UPDATE ACCEPT PDU to the BLE.
If the permission check is unsuccessful, MM-U rejects the registration to the MML, which sends out a D-LOCATION UPDATE REJECT. The MM-U also creates a log entry. On reception of an update request from a peer:
7.14.
●
The MM-U will update the local copy of the dynamic subscriber database.
●
If the peer was previously registered at the local site, the MM-U will inform the MM-L of the deregistration.
Deregistration of a Mobile/Dispatcher Deregistration of a mobile at a site is handled locally by the site and triggers an update of the distributed dynamic subscriber databases. For the deregistration of a mobile from the local site, the main operational steps map to the CSCIs as follows: ●
The MM-L receives a U-ITSI DETACH from the BLE, clears all AI L3 context for the mobile and signals the deregistration to the MM-U.
●
The MM-U then updates the local copy of the dynamic subscriber database, sends an update request to all peer entities and creates a log entry. On reception of an update request from a peer:
●
7.15.
MM-U updates the local copy of the dynamic subscriber database.
Call Set-up Procedure The main operational steps are as follows: ●
The CMCE-L receives a U-SETUP via the BLE and signals the call to the CMCE-U.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-17 Nr.: 6866500U01-D Author: Bryan Simcock
●
The CMCE-U consults the GDDB, detects that the call is local, and signals the call back to CMCE-L.
●
The CMCE-L then sends a D-SETUP to the BLE for the outgoing half-call.
Further call-related signalling is routed along the same path. The CMCE-L consults the AIRM, for allocation of air interface resources, at through connect and for half-duplex calls The AIRM will re-use the allocated channel for both the outgoing and incoming half-call.
7.16.
Inter-Site Call Set-up Individual calls between two mobiles registered at different sites are handled by the two sites without intervention of external central equipment. The main operational steps are as follows: ●
The CMCE-L at the originating site receives a U-SETUP from its BLE and signals the call to its local CMCE-U.
●
The CMCE-U consults the GDDB, detects that the call is an inter-site call and signals the call, via the inter-site communication platform, to its peer on the destination site.
●
The CMCE-U at the destination site signals the call to its local CMCE-L.
●
The CMCE-L then sends a D-SETUP to its BLE.
Further call-related signalling is routed along the same path between the CMCELs. The CMCE-Ls consult their AIRMs, for allocation of air interface resources, at through-connect.
7.16.1.
Calls Originating at the PABX/PSTN Gateway The PABX-GW receives a SETUP request from either the PABX or PSTN and signals the call to its local CMCE-U, which handles the distribution of the call as per the call set-up procedure. PABX-GW is responsible for the inter working of the signalling between the ISDN and the internal signalling protocol. On through-connect the switching layer at the Gateway PC allocates a Tetra codec to transcode the voice. If a mobile modifies a call to be half-duplex, the PABX-GW will clear down the call in both directions.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-18 Nr.: 6866500U01-D Author: Bryan Simcock
7.16.2.
Calls Terminating at the PABX/PSTN Gateway When the PABX-GW receives a call from its local CMCE-U, it signals the call to the ISDN. The PABX-GW is responsible for the inter working of signalling between the ISDN and the internal signalling protocol. At through connect, the switching layer at the Gateway PC allocates a Tetra Codec to transcode the voice and connects the inputs/outputs of the Codec to the appropriate channels on the ISDN. If a mobile modifies a call to be half-duplex, the PABX-GW will reject the call attempt .
7.16.3.
Calls Originating at a Dispatcher When the DISPSERV CSCI receives a call from a dispatcher, it signals the call to its local CMCE-U, which then handles the call set up. The DISPSERV CSCI is responsible for the inter working of the signalling between the Dispatcher access protocol and the internal signalling protocol. On through connect, the switching layer at the Gateway PC allocates a Tetra Codec to transcode the voice and sets up a VoIP connection between the dispatcher and the Gateway.
7.16.4.
Calls Terminating at a Dispatcher The DISPSERV CSCI receives a call from its local CMCE-U and signals the call to the Dispatcher. The DISPSERV CSCI is responsible for the inter working of the signalling between the Dispatcher access protocol and the internal signalling protocol. On through-connect the switching layer at the Gateway PC allocates a Tetra Codec to transcode the voice and sets up a VoIP connection between the dispatcher and the Gateway. Also the system allocates only one Tetra Decoder for all dispatchers monitoring a group call.
7.16.5.
Call Restoration Multi Site Call restoration is handled by the CMCE-U application at each sites. Up to three sites may be involved: ●
The old site where the moving subscriber previously held the call.
●
The new site where the call will be restored.
●
The peer site which hosts the other party in an individual call.
The main operational steps for restoration of an individual call are as follows:At the new site:
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-19 Nr.: 6866500U01-D Author: Bryan Simcock
The CMCE-L receives a U-CALL RESTORE indication from LLC and signals this to CMCE-U. To reduce the length of the speech break, the AI resource allocation may proceed in parallel with inter-site signalling. The CMCE-U uses the call identifier to locate the “old” site and signals the call restoration request to the old site. At the old site: The CMCE-U looks up the context related to the call and sends the call parameters, which includes information about the used E1 sub-channels and the peer site, back to the “new” site. It then checks to see if the call still has local participants, if not, it clears the call locally. At the new site: The CMCE-U signals the call restoration to the “peer” site, including information about the new E1 sub-channel bearing the speech of the moved subscriber. If the restored call is queuing for resources at this point, then this signalling will be delayed until resources become available. At the peer site: The CMCE-U updates the information and switches the downlink speech channel to the new E1 sub-channel. In the above, the “old” and “peer” may be the same site, as may the “new” and “peer”.
7.16.6.
Call Restoration – Group Call The restoration of a group call is as follows: The CMCE-L receives a U-CALL RESTORE indication from LLC and signals this to CMCE-U. To reduce the length of the speech break, the AI resource allocation may proceed in parallel with inter-site signalling. The CMCE-U uses the call identifier to locate and signal the call restoration request to the old site. At the old site: The CMCE-U looks up the context related to the call and sends the call parameters, which includes information about the used E1 sub-channels and the peer site used by the talking party back to the new site. At the new site: If the moving party is currently transmitting, the CMCE-U signals the information about the new E1 sub-channel bearing the speech of the moved subscriber to all peer entities participating in the group call.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-20 Nr.: 6866500U01-D Author: Bryan Simcock
If the restored call is queuing for resources at this point, then this signal will be delayed until resources are available. Otherwise, if another party is currently transmitting, it switches the downlink speech channel to read the E1 sub-channel of the talking party.
7.17.
Pre-emptive Priority Call Pre-emption Does Not place a call at the top of a queue. If someone with preemption wishes to talk to person ‘A’ who is already in a call, pre-emption will override this call and set the call up with person ‘A’. If a call is made with pre-emptive priority, the AIRM may clear down a call to free resources for the pre-emptive priority call. This applies to initial call set up, as well as to call restoration. There is no announcement of the imminent pre-emption to the pre-empted parties. At the dispatcher, a call with pre-emptive priority is indicated as an incoming call with dedicated signalling. If the incoming call queue at the dispatcher is full, one call is immediately preempted and the priority call is displayed.
7.18.
CLIP and TPI All signalling interfaces in the system carry Calling Line Identification Presentation (CLIP) and Talking Party Identification (TPI) information for presentation to the user. No other provisions exist for CLIP and TPI. If a call is to an external number, the PSTN/PABX Gateway builds the calling party information element, into the outgoing SET UP, from a decimal representation of the calling party’s SSI and an optionally configured prefix string.
7.19.
Subscriber Data Management Subscriber Management is used to define both the Short Subscriber Identity (SSI) and the user rights for each MS. The subscriber data is distributed through out the system as text files. The synchronisation of the subscriber data is controlled by the Gateway. The user interface for changing the subscriber data is implemented at the Gateway & Dispatcher PCs. The Base Stations are updated via the Subscriber Profile and Configuration Data Distribution.
7.20.
Short Data Service (SDS) There are 2 types of service available: ●
Status messages (16 bit integer)
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-21 Nr.: 6866500U01-D Author: Bryan Simcock
●
SDS messages (140 characters) SDS messages can be exchanged between mobiles and dispatchers. At the dispatcher, the content of SDS message will be displayed in plain text, status messages are also converted to text. The SDS is distributed internally between the different Base Stations and to/from the Gateway PC, via the signalling interface (inter-site communication layer). Between the Gateway-PC and Dispatchers, the SDS messages are transferred via IP connectivity.
7.21.
Packet Data Packet data is handled by the SNDCP-L, SNDCP-U, and PDG CSCIs. Packet data routing in the system is based on the SSI of the subscriber being associated with a unique IP address. The system supports the mobility for subscribers engaged in packet data transmissions. At the packet data gateway, the Tetra system appears as a Class B IP subnet.
7.22.
Logging and Tracing Each node in the system (cells and Gateway PC), as well as mobility management and group management actions, creates log files for all successful and unsuccessful calls. Collation and filtering of log files is not implemented at the sites. The sites provide automatic log file rotation and will delete old log files after a configurable time. If the data base is full, the oldest file is deleted to allow the new file to be added. There is no warning when the data base is full.
7.23.
System Start-up Each system component enters operational mode autonomously after a powerup. The inter-site communication protocol provides an up-to-date view of the current state of the system to all components and to the Operations and Maintenance application. If a site powers up, it will attempt to synchronise its configuration data and software versions with those stored at the Gateway PC. If a site comes up while the Gateway PC is unreachable, it will use its locally stored configuration.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-22 Nr.: 6866500U01-D Author: Bryan Simcock
7.24.
GPS Interface This provides an accurate measure of real time to the system for the time stamping of call logs and system synchronisation.
7.25.
BSC-Transceiver Interface It consists of three interfaces:
7.25.1.
7.25.2.
The Clock Interface. ●
It drives three clock lines with frequencies of 2048kHz, 8kHz, and 1Hz respectively.
●
The 1Hz second tick is synchronised with the external time base derived from either the GPS Interface, E1 link or internal oscillator.
●
If the clock is derived from either the E1 link or the internal oscillator, it will not be absolute and it would need setting for summer time etc.
The PCM Highway. This is used for the transmission of Tetra U-plane data. The BSC provides four bi-directional PCM highways, each with a data rate of 2048kbit/s. The PCM links are clocked with the 2048kHz signal from the clock interface. A frame structure with a frame rate of 8kHz is imposed on the bit stream by the 8kHz signal from the clock interface to give a capacity of 32 timeslots per PCM link. In the transceiver, the Tetra U-plane data of one traffic channel is rate-adapted to 8kbit/s and transmitted in the least significant bit of a 64kbit/s timeslot on the PCM highway. As each transceiver uses four timeslots on the PCM highway, a maximum number of eight transceivers can be connected to one PCM link. In the BSC, the PCM links lead to a cross-connect that is capable of switching 8kbit/s sub-timeslots and is controlled by software.
7.25.3.
The HDLC bus. This is for the transmission of control information and Tetra C-plane data. The BSC provides four bi-directional HDLC busses at a data rate of 2048kbit/s each. The busses are clocked with the 2048kHz signal from the clock interface. The retransmission features of HDLC are not used. In the direction from the BSC to the transceivers, the BSC is master and addresses the transceivers using HDLC addressing, either individually or using broadcast.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-23 Nr.: 6866500U01-D Author: Bryan Simcock
In the direction from the transceiver to the BSC, a contention control protocol makes sure that messages are not lost due to simultaneous transmission attempts by two or more transceivers. The HDLC interface carries all Tetra C-plane data and all control messages between the transceivers and the BSC.
7.26.
Inter-Site Interface This is provided by E1 links and Depending of the size of the system, the number of used timeslots in the E1 links will vary. A rough estimation of the necessary timeslots can be found with the following formula: TS = carriers/2 + 1 + (sites-1)/2 + packet data channels (64 max)/8
7.27.
Carriers …
number of carriers in the system
Sites …
number of base stations in the system
Packet data channels …
number of AI slots used concurrently for data
U-plane Communication Tetra coded voice is exchanged between all nodes on the E1 links in dedicated sub slots of 64 kBit/s channels. All slots are available at all Base Stations and the Gateway at any time. The necessary switching between slots on the E1 links and the Air Interface is performed locally.
7.28.
Signalling Communication The inter-site communication layer offers acknowledged and unacknowledged point-to-point transfer, as well as unacknowledged broadcast communication. The communication protocol uses HDLC on a subset of the E1 links. It uses segmentation and reassembly for larger messages to limit the maximum delay for short, urgent messages. It uses a two-level priority scheme. It offers reliable transmission by transmitting each message on both E1 links of a multi site system and removes duplications on reception. The inter-site communication layer also monitors the state of all nodes and links in the system and offers this status information to the distributed application layer. The inter-site communication layer is not concerned with the content of messages.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-24 Nr.: 6866500U01-D Author: Bryan Simcock
7.29.
Management Communication IP is used to transfer management information throughout the network. The IP communication uses HDLC over the E1 links and inter works with the standard Windows NT IP protocol stack. Thus, management applications can make use of standard IP-based protocol, e.g., FTP.
Note: Tetra packet data is not transferred as the inter-site IP datagrams.
7.30.
Dispatcher Interface (DA-IF) The interface between the Gateway and the Dispatcher is based on IP (voice over IP, VoIP) via a 100Mbit/s Ethernet. This uses standard TSAPI software that comes with the Windows OS.
7.31.
BSC Ethernet Interface The BSC supports a standard 100baseT Ethernet interface. This interface is used for the connection of a PC for Local site configuration.
7.32.
BSC RS232 Interface The BSC supports a standard RS 232 interface and is used for standalone site configuration.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-25 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:7-26 Nr.: 6866500U01-D Author: Bryan Simcock
8.
Accessing the BSC Locally The PC being used to configure the BS must have the correct IP address. If the BSC Ethernet address is not on the front panel above the connector, remove the BSC card and look for the number on the mother board between the front panel and the screening cover, i.e. assume the address is 10.10.99.6 Replace the BSC. Configure the PC with an address of: e.g. 10.10.99.70 (any number not 6) and a subnet mask of: 255.255.255.0 Using a crossed cable, connect the PC, via the Ethernet connector, to the BSC. Start Netmeeting and select the telephone (Place Call) icon. Enter the address 10.10.99.6 and check the ‘Require Security for this Call’ box. At the prompt enter ‘administrator’ in both the ‘User’ & ‘Password’ prompt boxes. The PC now displays the active window of the BSC. This shows the main window, with application icons displayed on the left and at the bottom of the window, overlaid with the active Tetra applications – DO Not Close any of these applications. Us the ‘Minimise’ screen option to remove the application screens from the window. Once an option has been actioned using the mouse pointer, the mouse pointer may no longer be visible as the resolution of the PC is different to that set on the BSC. Move the mouse off the NetMeeting window to the PC screen, the pointer will now be visible, click on the PC screen and the pointer will again be visible on the NetMeeting Window. Select the ‘My Computer’ icon (it may be necessary to move the BS1 window to the right to display the icon) and then follow the path: C:\Tetra\Work\Config. Open the ‘bssfactoryparams.txt’ file and start the BSC configuration.
8.1.
Frequency Configuration Each Transceiver frequency is entered, as a step size, in the BSC. The actual frequencies, receiver frequency first, must also be entered into the CONFIG_SBSC file on the BSC. The BSC is able to support frequencies with 25KHz, 12.5KHz and 6.25KHz offsets The Transceivers only support 12.5KHz.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:8-1 Nr.: 6866500U01-D Author: Bryan Simcock
It is not possible to have both 25KHz and 12.5KHz steps running simultaneously on the different Transceivers of one BS. On multi-site systems, all System Transceivers MUST have the same offset of 25KHz to enable correct adjacent site information to be transmitted.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:8-2 Nr.: 6866500U01-D Author: Bryan Simcock
9.
Dispatcher Workstation CTD-1 The Dispatcher’s work includes co-coordinating the communication of users and teams from a command and control center. To do this, a dispatcher carries out individual calls, group calls and sends and receives SDS messages. The Dispatcher video screen provides graphic elements for easy operation:
The Dispatcher workstation comprises the following items and interfaces: Personal computer including 17inch flat screen monitor and Ethernet interface for connection to the Gateway PC. • Keyboard and mouse to operate the states of the dispatcher application program • Monitor loudspeaker to observe speech communication of up to 5 monitored groups. The speech is presented as mixed signal • Headset or handset to communicate to the currently focused call • External PTT Note: A switch (not provided as part of the system deliverables) that technically is equivalent to, or better than the HP Procurve Switch Type 2512 must be used when connecting more than one dispatcher console to a system. •
9.1.
Dispatcher operation The following tasks can be activated at the Dispatcher workstation. Each task is available as a separate application, which can run in parallel with the others. These functions are described in detail in the section “System Configuration”. Call Management This application allows the dispatcher to co-ordinate and monitor terminal users and groups of terminal users. The application allows the dispatcher: •
Handle several Individual Calls in parallel
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:9-1 Nr.: 6866500U01-D Author: Bryan Simcock
Monitor and participate in up to 5 Group Calls in parallel • Send and receive Status SDS messages • Send and receive Text SDS messages The dispatcher application provides high-level status information about the base stations and the network interconnections. •
The following applications are available on the Dispatcher PC, but preferred operation is from the Gateway PC. Each application can run in parallel with the others. Subscriber management This application is used to add Subscriber radios, terminal users IDs (ISSIs) and group IDs (GSSIs), to the network and define the system features available to a radio. System management This application allows remote configuration of all the sites, the interfaces to the E1 network, the ISDN and the Packet Data interface. The system management application also allows the base station software to be updated. System monitoring This application provides detailed information about the operational status of all system components; it details the traffic load and displays the system alarm messages.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:9-2 Nr.: 6866500U01-D Author: Bryan Simcock
10.
Gateway Server CTG-1 The Gateway Server is the interface between the TETRA network (E1-ring) Dispatchers and the PABX/PSTN and IP-Network for Packet Data transfer. From the internal network point of view the gateway PC is just an additional node in the E1 ring. In addition, the Gateway PC holds all the log files of the entire system. Interfaces: • • • •
1 or 2 E1-Links to the base stations 1 ISDN T0 card (4xISDN = 8 Lines) to connect up to 8 PABX/PSTN subscribers to the network 1 x 100Mbps Ethernet interface to connect up to 8 Dispatcher Workstations (using an additional switch) 1 x 100Mbps Ethernet interface to connect IP-based packet data plus SDS applications to the network
The following tasks can now be activated at the Gateway PC. Each task is available as a separate application, which can run in parallel with the others. These functions are described in detail in the section “System Configuration”. Subscriber management This application is used to add Subscriber radios, terminal users IDs (ISSIs) and group IDs (GSSIs), to the network and define the system features available to a radio. System management This application allows remote configuration of all the sites, the interfaces to the E1 network, the ISDN and the Packet Data interface. The system management application also allows the base station software to be updated. System monitoring This application provides detailed information about the operational status of all system components; it details the traffic load and displays the system alarm messages. The monitored system activities are: • • • • • • • • • •
Number of current individual calls in the system Number of current individual calls at a Base Station Number of current group calls in the system Number of current group calls at a Base Station Number of current packet data connections at a Base Station Number of SDS transferred within the last minute at a Base Station Status of the E1 links (up/down) Status of the Base Stations (up/down) Status of the redundant BSCs (main/standby/down) Status of the Transceivers (up/down)
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:10-1 Nr.: 6866500U01-D Author: Bryan Simcock
System Arrangement Showing Gateway PC
10.1.
The NMS.cfg Configuration File The NMS.cfg file contains Topographical information about the system and must be edited to incorporate additions & deletions to the system i.e. Base Stations or Dispatcher Consoles. When a new base station is added to this file, a corresponding folder will automatically be created for it in the Network Management application. The folder is given the name entered in this file i.e. BS1, BS2 etc. This folder is needed for remote configuration of the base station. Follow the path: System C:\Tetra\Work\NWMA\Config Within this folder are several configuration files, the ALS.cfg & NWMC.cfg files are defaults and must not be edited. To open the NMS.cfg file, use the right mouse button, select the file and at the option ‘Open With’ select ‘Notepad’.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:10-2 Nr.: 6866500U01-D Author: Bryan Simcock
10.1.1.
The NMS.cfg File [NetTopology]
(Add or Delete entries here to reflect system changes)
BS1= BS 192.168.0.1 777 23:40:00 00:00:00 (Timers for log download). BS2= BS 192.168.0.2 777 23:30:00 00:00:00 GWPC= GW 192.168.100.16 777 23:50:00 00:00:00 [Long names]
(These names can be anything, i.e. BS1=”Basingstoke”. These long names are used with the network management application and are not to be used anywhere else).
BS1="BS-1“
(Use BS-1, BS-2 etc in the config files (E1 link descriptions), this terminology is used by the system software and does not recognise other terminology).
BS2="BS-2" (BS3=”BS-3”
Add or Delete entries here to reflect system changes).
GWPC="Gateway” (In the nms.cfg file the long name for the Gateway must be gateway and not GW-PC. This failure triggers problems with the network management together with FTP activities). [NMS] Port=2010
(Do Not change this entry)
[Authorization] File=C:\Tetra\Work\Config\passwd
(This defines the FTP password, do not alter)
Note *: BS1= BS 192.168.0.1 777 23:40:00 00:00:00 - This entry sets the time of the base station log downloads to the GWPC. BS1= BS 192.168.0.1 Base Station ID
777
23:40:00
BS IP address Absolute Time Setting Port Number
02:15:00
Delta Time Setting
The Absolute Time defines the one time during the day when the log file download will occur. The Delta Time defines the time interval between repeated log file downloads. These times must have 10 minute intervals between successive base station downloads. Note: If a log file data base becomes full, the log scavenger will automatically download the files to the NWMA.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:10-3 Nr.: 6866500U01-D Author: Bryan Simcock
10.2.
Network Management Configuration (NMA) The NMA must be configured correctly to enable remote configuration of base stations. The configuration is ensuring that the information contained within the sub folders for each base station is also reflected at the corresponding base station. To open the folder follow the path: System C:\Tetra\Work\NWMA
Within the NMA folder will be the BS folders created from the information in the NMS.cfg file. Each BS folder contains two sub folders, the ‘Config & Log’ folders.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:10-4 Nr.: 6866500U01-D Author: Bryan Simcock
Within the ‘Config’ folder are 3 different types of file and each type of file is number sequentially. The bssfactoryparams and TVV files work together for remote base station configuration and it is advisable to rename them similar to those above, bssfactoryparams_bs1_0001.txt and bs1-0001.tvv for your first files. The bssfactoryparams files is a copy of the file from the base station and by numbering them in this manner, it will prevent accidental updating of the wrong base station. The numbering of these files is manually increased when remotely configuring base stations. The dbv files update the subscriber data base information held at each base station. The numbering of the dbv files must also correspond to those held in the SUMZip folder, see below. Ensure dbv file numbers are not higher than those in the SUMZip folder.
All these files are held on the base station (BS1), see below, and if the numbering goes out of sequence (the file numbers are higher at the base station) the files will not be updated from the Gateway.
On successful update to a base station, tvv & dbv file extensions change to cvv & cbv.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:10-5 Nr.: 6866500U01-D Author: Bryan Simcock
If an extension is either ivv or ibv, it is invalid and the update was not successful. Note: If something has not happened/not worked/not started, ALWAYS check the log folder and look at the VCDaemon & Watchdog log files.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:10-6 Nr.: 6866500U01-D Author: Bryan Simcock
11.
Packet Data Gateway With IP-based Packet Data, a mobile user can be connected to a central database. This supports the integration of customer related IP applications. The Tetra-channel is only occupied when data are transmitted over the system. This concept is a “must” for future digital communication systems; it allows the user to be “on-line” anytime, anywhere and enables a wide range of applications as for example: Access to the corporate Intranet • E-mail • Data base enquiry • File transfer • Internet access • Automatic Vehicle Location System (AVL) for optimized fleet management • Telemetry The Packet Data gateway is accessed through a dedicated 100Mbps Ethernet interface at the Gateway PC, which is part of the basic configuration. No extra hardware is required. •
A large number of accredited Motorola application partners have developed and integrated applications for Compact TETRA using the Packet Data Gateway or the Peripheral Equipment Interface (PEI). They are ready to develop more applications on customer needs. The approval process recognizes and certifies the robustness and performance of a partner’s Compact TETRA compact system.
“Information Access Anytime & Anywhere”
Packet-data Gateway
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:11-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:11-2 Nr.: 6866500U01-D Author: Bryan Simcock
12.
Connecting a Server to the Packet Data Gateway
12.1.
Gateway LAN (Server) Port See Section 3, Fig. 5-3 for the port. To find the IP address and Mask of this port select the following route: Start/Settings and at the options right click on ’Networks’ and select open. Four local area connections will be displayed and if there is no cable connected to the LAN (server) port it will have a status description of ‘Network Cable Unplugged’ and its device name is ‘Intel(R) Pro/100 VM Network Connection’. Select this option and double click on it with the left mouse button to open its properties. Select the Internet Protocol (TCP/IP) option and then choose properties to display the IP address and mask for the port. E.G. IP Address = 10.192.96.16 Mask = 255.255.255.0
12.2.
At the Server: If using a PC as the server, select : Start/Run and at the prompt enter to put the PC into DOS mode and then: 1. Enter Where: The 1st address (192.168.200.0 with a mask of 255.255.255.0) is the PDG LAN on the GWPC. The 2nd is the port address (10.129.96.16) of the GWPC LAN (Server) port 2. Enter Where: The 1st address (192.168.0.0) is the WAN (E1) on the GWPC.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:12-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:12-2 Nr.: 6866500U01-D Author: Bryan Simcock
13.
Connecting a PC to a Radio The following information will allow a PC, using the appropriate data interconnect cable, to connect to a radio and access the system. If this does not happen there is a problem with the PC. The PC may be configured to work on the company’s LAN and must now be reconfigured to work on the radio network. As the PC is normally working on the company LAN it contains security software that: •
Restricts access
•
Is anti virus
•
Is a Fire Wall
If the PC is running something like ‘BlackIce’, the PC will never work with the radio, so this application must be stopped for the duration that the PC is connected to the radio. It may also be necessary to either stop other applications or change their default settings. To stop applications follow the path: Start/Settings/Control Panel/Administrative Tools/Services This window displays the applications on the PC.
13.1.
PC Configuration Once the PC has powered up, select the following path: Start/Settings/ Using the mouse, right click on Network Connections to open the application and then select the option ‘Create a New Connection’.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-1 Nr.: 6866500U01-D Author: Bryan Simcock
When the new connection screen opens select the option ‘Next’, to open the Network Connection Type window.
Chose the option for direct connectivity via a cable to another computer, this is normally the bottom option. Select ‘Next’ to open the Advanced Connections Options window and choose the option ‘Connect Directly to another Computer via the serial port.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-2 Nr.: 6866500U01-D Author: Bryan Simcock
Select ‘Next’ to open the ‘Host or Guest’ window and select the ‘Guest’ option, remember this PC will be a ‘guest’ on the system.
Select ‘Next’ to open the ‘Connection Name’ window. Here a name or alias can be entered for the connection, i.e. Tetra Connection.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-3 Nr.: 6866500U01-D Author: Bryan Simcock
Select ‘Next’ to open the ‘Select Device’ window that defines the port that will be used for this connection.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-4 Nr.: 6866500U01-D Author: Bryan Simcock
Select ‘Next’ to open the final window ‘Completing the New Connection’. There is an option here to place a short cut on the desk top(recommended). To create the connection and close the application select ‘Finnish’.
Note: The screen shots shown above are taken from Microsoft XP and may be different for other Microsoft versions, but the connection method will be the same.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-5 Nr.: 6866500U01-D Author: Bryan Simcock
13.2.
Dial-Up Connection Settings Again dependent upon the version of Microsoft running on the PC will be when the modem settings are configured. An easy method of doing this is to select the desktop dial-up icon and open the connection.
Select Properties:
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-6 Nr.: 6866500U01-D Author: Bryan Simcock
Select the ‘General’ tab and ‘Configure’.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-7 Nr.: 6866500U01-D Author: Bryan Simcock
Select the above options:
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-8 Nr.: 6866500U01-D Author: Bryan Simcock
Set the above options and then select the Security tab:
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-9 Nr.: 6866500U01-D Author: Bryan Simcock
Select the above option and then choose the Networking tab:
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-10 Nr.: 6866500U01-D Author: Bryan Simcock
Select the ‘Settings’ option.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-11 Nr.: 6866500U01-D Author: Bryan Simcock
Ensure none of the PPP settings are checked, select OK to return to the main Networking screen. Ensure the Internet Protocol (TCP/IP) option is highlighted, then select Properties.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-12 Nr.: 6866500U01-D Author: Bryan Simcock
Ensure the above options are checked. Select OK and the Sharing tab.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-13 Nr.: 6866500U01-D Author: Bryan Simcock
Ensure nothing is checked in this window. Select ‘OK’, return to the main screen and choose cancel to close the application.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-14 Nr.: 6866500U01-D Author: Bryan Simcock
13.3.
Accessing a Server via a Radio/PC Connection The object of connecting a PC to a radio is to allow data connectivity to a LAN (Server). To enable this, the address route for the server must be added to PC’s routing table To enable through system connectivity, PC to Radio to CT System to Server, the PC must have the server ‘Route’ added to its ‘Routing Table’. E.G. On the Laptop connected to a Radio: Open window and enter Where: The 1st address (10.192.96.0 with a mask of 255.255.255.0) correlates to the IP address of the Gateway LAN (Server) Port (see 11.0 below). The 2nd is the IP address assigned to the connected radio in the System Database.
13.4.
Setting Up The Packet Data Connection With the PC powered up, connect the appropriate data cable, for the radio being used, to the serial port of the PC. Ensure the radio is powered up before connecting to the data cable. When connect the radio to the data cable, it will sound a confirmation tone that the connection is ‘good’. Select the ‘Dial-Up’ icon on the desk top and when it is open select ‘Connect’, Password entry is not required.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-15 Nr.: 6866500U01-D Author: Bryan Simcock
The Connecting Direct Connection window will be displayed on top of the PreDial Screen. Click on the Pre-Dial Screen and the cursor will be shown under ‘OK’. Enter the command ‘ATO’ (this will not be visible in the window) and press enter.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-16 Nr.: 6866500U01-D Author: Bryan Simcock
The Pre-Dial Screen will now be active, select ‘Continue’. The radio will display the prompt ‘Attempting to Register on the System’ and on successful completion will display the prompt ’Connected to the System’. The radio is now registered on the system in data mode and ready to pass data.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-17 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:13-18 Nr.: 6866500U01-D Author: Bryan Simcock
14.
Account Management If an account management application is being used with the system, it is assumed that it will be running on a separate PC connected to the Gateway PC. In which case if a LAN (Server) is connected to the Gateway, a switch will be required as both will be using the same port on the gateway. Requirements: •
Crossed Ethernet cable.
•
PC configured to GWPC.
The IP address of the GWPC port is: 10.192.96.16 (see 11.1 above) therefore the TCP/IP address of the PC must be: 10.192.96.?? where ?? is any number other than 16 Once the PC has been configured and connected to the GWPC map network drives. During this process a prompt will be displayed asking for the ‘User & Password’, this is the same for connectivity to a base station, i.e. ‘administrator’ Note: It is also possible to back up files to a PC using the above method Follow the path: c:\Tetra\Work\NWMA\BS1\Log to download the files from BS1.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:14-1 Nr.: 6866500U01-D Author: Bryan Simcock
14.1.
Feature Description (Single and Multi-Site) Release
Feature/ Function
Description
R1
Individual Call
Full duplex and semi-duplex calls from and to terminals, dispatchers and telephone subscribers
R1
Group Call
Semi-duplex call to terminals and dispatchers
R2
Pre-emptive Emergency Group Call
This feature provides a pre-emptive function to clear a channel with lower priority in case all traffic channels are too busy to operate an emergency call
R1
SDS
Short Data Services using pre-defined text messages or alphanumeric text with up to 140 Characters using the Main Control Channel (MCCH). Text according to ISO/IEC 88591 Latin.
R2
Packet Data
Single slot packet data using the traffic channels to connect the terminals to IP based 3rd party applications
R1
Call Queuing
Call will get through without the end-user having to retry if the network is busy - high quality of service
R1
Late Entry Group call
The group call is sent over the air periodically during the lifetime of the call, users that were not originally in the group call can join the call as they become available
R1
Extended Call Timer
If required the call timer can be set to infinite
R2
Cell Reselection and Call Restoration
This system feature of TETRA lets a terminal roam between cells while engaged in a call without releasing the call.
R1
CLIP (limited)
Calling Line Identification Presentation. The identification of the calling party will be shown at the terminal of the called party (not via ISDN)
R2
Dynamic Paging Area for Group Calls
An intelligent paging strategy activates only those base station where the terminals are located
R2
Fractional E1
In order to save cost on smaller systems only a fraction of the 2 MBit E1 link need to be assigned to the infrastructure
R1
Dispatcher Language
Dispatcher capable of multi-language support
R2
Remote SW download
New SW-releases can be downloaded from the Dispatcher/Network Mgmt workstation to the base stations. No need to visit the site for SW upgrades.
R1
Call Capacity
The switching capacity is not a limiting factor – even with max. number of subscribers and base stations
R1
Digital Audio
The audio specifications are in line with established best practices
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:14-2 Nr.: 6866500U01-D Author: Bryan Simcock
14.2.
System configuration overview Configuration Item
Transceivers per BS BS per system Transceiver per system Gateway PC Dispatchers Subscribers per system ISDN Interface (4xISDN) provides 8 PABX/PSTN channels SDS Gateway Interface Packet Data Interface Tolerance against Link Failures
Compact TETRA COPYRIGHT Motorola 2002
Standalone
Single Site
1–8 1 1–8 0 0 2.500
1–8 1 1–8 1 0–8 2.500
Multi Site, Open E1 chain 1–8 2–8 2 – 32 1 0–8 10.000
Multi Site, Closed E1 chain 1–8 2–8 2 – 32 1 0–8 10.000
No
Yes
Yes
Yes
No
1
1
1
No N/A
1 No
1 No
1 Yes
Intro & System Overview R3_0.doc Page:14-3 Nr.: 6866500U01-D Author: Bryan Simcock
14.3.
System parameters and specification The table below describes the important system capabilities and parameters Item Speech delay (unloaded system)
Echo cancellation at PABX/PSTN Gateway Failure recovery time
Standards and R&TTE Climatic Environment
IOP Dispatcher LAN Packet Data Gateway MTBF
Compact TETRA COPYRIGHT Motorola 2002
Specification The delay is measured when the speech enters the system via microphone and ends when the speech leaves the system: 50.000 hours
Intro & System Overview R3_0.doc Page:14-4 Nr.: 6866500U01-D Author: Bryan Simcock
14.4.
Base Station Specification Item
Specification
Standards
ETS300 394-1
Frequency Bands
380 - 400MHz 410 – 430 MHz 450 – 470 MHz 805 – 870 MHz
Transceiver Bandwidth
10Mhz
Duplex Separation
10MHz, 45MHz (805-870MHz)
Carrier Separation
25KHz (when using Cavity Combiner the minimum space between 2 carriers should be >175KHz)
TX power
2,5 – 25W TETRA before combiner 1-10W after combiner
Receiver Diversity
Dual Receiver Diversity
Combiner System
Hybrid combiner for CTS100 (1 or 2 carrier) and optional for CTS200 Cavity combiner for high capacity base station (1-8 carrier)
Power source
-48V/-60V DC input voltage (positive pole grounded) and 90-269VAC, 47-63Hz including battery charge function for 48 VDC external batteries
Temperature range
-20°C to +55°C Operational temperature range
Base Station Controller
High performance low-power Pentium PC with solid-state flash disk. Windows NT-E Operating system. Automatic switchover to redundant BSC at failure. GPS receiver build-in for time and frequency synchronization. Ext. GPS antenna to be provided by customer.
E1 Interface
2 x E1 with 120 Ohm Impedance
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:14-5 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:14-6 Nr.: 6866500U01-D Author: Bryan Simcock
15.
Radio (MS – Mobile Subscriber) Registration At power up or when roaming between cells, the MS automatically sends a registration request to the system so that it can be logged onto the network and use the available services. The registration transmission may include a request to attach to one group, identified by its GSSI. e.g. the last group to which the mobile was attached. The system can either accept or reject the registration and can also accept or reject the group affiliation with the same message. If the mobile is already registered in a cell, the system resends the registration result. The system does not support multiple registrations, i.e. the size of the registration area (RA) is always one LA. The maximum time that a mobile will wait for a registration response is 30 seconds. If nothing comes back during this time it means the system has internal trouble in that cell. If possible, the mobile will try to register on another cell. The system is able to answers a registration request within 300 milliseconds if the system is not loaded. Note: This does not allow for the delay, both ways, through the subscriber unit (MS).
15.1.
Mobile De-registering A mobile may request de-registration when: ●
It is switched off.
●
User specific information, including its Individual Tetra Subscriber Identity (ITSI or ISSI), is removed from the radio.
●
The mobile may optionally inform the system that it is leaving the trunking mode before selecting direct mode operation and will no longer be reachable.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:15-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:15-2 Nr.: 6866500U01-D Author: Bryan Simcock
16.
Call Release The call lasts until one party actively releases the call. In case of a semi-duplex call, the call will be released by the system when the inactivity timer expires. In case of a full-duplex call the system starts a configurable call timer after through connect and clears the call on expiry of the timer.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:16-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:16-2 Nr.: 6866500U01-D Author: Bryan Simcock
17.
Reasons for Call failure The called party is unknown or not registered or not reachable. System internal resources are exhausted. In case of break-down of a participating remote system component, i.e. another base station or the gateway PC, the system will release the call autonomously.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:17-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:17-2 Nr.: 6866500U01-D Author: Bryan Simcock
18.
Group Attachment / Detachment If the mobile wishes to operate with no selected group (private mode), it is able to send the null group identity (FFFFFF16) as part of the attachment message. The null group attachment is always acknowledged positively by the system. The mobile may leave the group to which it is attached by sending a UAttach/Detach-Group-ID detachment message. The detachment is always acknowledged positively by the system. The maximum time a mobile waits for a response to an attachment request is 10 seconds. The system will acknowledge a received U-Attach/Detach-Group-ID message within 1 second in a no load condition.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:18-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:18-2 Nr.: 6866500U01-D Author: Bryan Simcock
19.
Transmission Control The system supports Transmission Control of semi-duplex individual calls and group calls. Transmission requests may come from both mobiles and dispatchers. The system will reject any transmission requests for duplex calls if the caller’s transmission request permission is set to ‘not allowed to request permission to transmit’. The system does not support queuing of transmission requests and it will either be immediately granted or rejected. Transmission control has the following states: •
Idle, this means that no party is currently transmitting and on reception of a Tx-Demand, the system will immediately grant transmit permission.
Transmitting, this means that one party is transmitting and on reception of a Tx-Demand the system will either reject the request or interrupt the currently transmitting party and grant transmission to the demanding party. The following table shows the decision matrix for either rejecting the request or •
interrupting the transmitting party.
Tx Priority
0
Request
1
2
3
R
R
R
Priority
R
0
R
R
R
R
1
I
I
R
R
2
I
I
I
I
3
I
I
I
I
Tx Priority = Transmit priority of currently transmitting party. Request Priority = Priority of requesting party. R = Reject. I = Interrupt.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:19-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:19-2 Nr.: 6866500U01-D Author: Bryan Simcock
20.
Call Restoration This Tetra system feature enables a mobile, while engaged in a call, to roam between cells without releasing the call. The mobile leaves the serving cell, selects the new cell (as it does for cell reselection) and, if necessary, performs registration. The system supports unannounced cell reselection. The system provides the information to the mobile, for call restoration, on the MCCH of the new cell. In case of queuing conditions at the new cell, the system will give priority to the restored call over all other queued calls.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:20-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:20-2 Nr.: 6866500U01-D Author: Bryan Simcock
21.
Pre-emptive Priority Call The system supports individual pre-emptive priority calls originating from a subscriber unit to a Dispatcher. All other combinations of source and destination subscribers are not supported. In case of contention at the AI, the system will gain the necessary resources by releasing a call without prior indication to the involved subscribers. At the Dispatcher HMI, all pre-emptive priority calls are placed at the top of the incoming call queue and the dispatcher is alerted to its presence. Even if requested in the U setup, the system will not through connect the call to the dispatcher.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:21-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:21-2 Nr.: 6866500U01-D Author: Bryan Simcock
22.
CLIP and TPI The system provides the following: Identification of the calling party to the called party (CLIP). In a semi-duplex group call, identification of the talking party to all listening parties (TPI). Full implementation is not until phase 3 release, 2004.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:22-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:22-2 Nr.: 6866500U01-D Author: Bryan Simcock
23.
Failure of a Traffic Transceiver The system frees all resources associated with the failed transceiver and the Base Station does not attempt to use the transceiver for further communication. The base station remains operational, but with reduced carrier capability and an error log entry is produced. If the Base Station finds a transceiver is not available at startup (checked against configuration data), then an error log-entry is produced.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:23-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:23-2 Nr.: 6866500U01-D Author: Bryan Simcock
24.
Failure of the MCCH Transceiver The system frees all resources associated with the failed transceiver and the Base Station does not attempt to use the transceiver for further communication. The base station remains operational, but with reduced carrier capability and an error log entry is produced. The Base Station assigns the MCCH to one of the remaining transceivers, reconfigures all transceivers accordingly and resumes operation. An error log-entry is produced. All local registrations and all communication at the Base Station are lost due to this action.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:24-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:24-2 Nr.: 6866500U01-D Author: Bryan Simcock
25.
Failure of Base Station Controller (BSC) In case of failure of the Base Station Controller, the TETRA application will automatically start up on the 2nd Base Station Controller (if available) and reintegrate into the system. All local registrations and communications at the Base Station are lost due to this action. If there is not a standby BSC, the system will loose the base station completely.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:25-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:25-2 Nr.: 6866500U01-D Author: Bryan Simcock
26.
The Tetra Air Interface Tetra is a ETSI standard, developed in Europe, that enables a subscriber to roam between networks Internationally. Tetra Modulation Tetra uses the p/4 DQPSK modulation technique. This is a phase shifting technique used in narrow band radio systems and is the standard used in American digital cellular systems. 36kbps can be transmitted over 25kHz channel spacing with little adjacent channel interference if the transmitted spectrum is very tight and there is good filtering. The TETRA standard has mandatory and optional elements, of which Compact TETRA does all the mandatory aspects and some of the optional ones. Tetra is supported by the following Pan European frequency bands. Public Safety 380MHz
390MHz
400MHz
Uplink
Downlink 10MHz Duplex Spacing
Public Access 410MHz
420MHz
430MHz
Uplink
Downlink 10MHz Duplex Spacing
General PMR 450MHz
460MHz
Downlink
Uplink
470MHZ
10MHz Duple Spacing
870MHZ
888MHz
915MHz
Uplink
933MHz Downlink
45MHz Duplex Spacing
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:26-1 Nr.: 6866500U01-D Author: Bryan Simcock
APAC/LACR 425MHz
806MHZ
851MHz
Uplink
870MHz Downlink
45MHz Duplex Spacing
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:26-2 Nr.: 6866500U01-D Author: Bryan Simcock
27.
Time Division Multiplexed Radio Carriers What used to be referred to as a radio channel is now called a Tetra Carrier. The term carrier always relates to 25kHz bandwidth frequency i.e 1 TETRA Carrier = 1 x 25kHz analogue channel. Each carrier is divided into 4 virtual channels or time slots and these are either Uplink or Downlink carriers dependent on direction of transmission. Tetra radio carriers are allocated in duplex pairs, each downlink timeslot being matched to its uplink peer. The uplink and downlink slots are numbered identically, but are offset by a 2 slot time period which avoids the necessity for full duplex radio hardware and a frequency difference of either 10MHz or 45MHz, dependent on frequency band used. The complexity of the Air Interface enables a very flexible use of these carriers for different call making activities. 1 Hyper frame = 60 multi frames = 61.2secs 1
2
3
4
60
5
1 multi frame = 18 TDMA frames = 1.02secs 1
2
3
4
5
18
1 TDMA frame = 4 timeslots = 56.67ms 1
1
2
3
4
5
2
3
4
Control Frame
510
1 timeslot = 510 modulation bits duration = 14.167ms
27.1.
Slot Structure Vocoded voice has a fixed frame size and is the same in the uplink and downlink directions. Due to the need to ramp up of the MS transmitter power and linearise the PA, the down link capacity is slightly greater than that of the up link (approx 30 bits, even allowing for the insertion of an intermediate training sequence). The extra down link capacity is used to transmit lower layer MAC information, this is called:
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:27-1 Nr.: 6866500U01-D Author: Bryan Simcock
•
The ‘Broadcast Block’ at the physical layer, since it is present on every down link slot.
•
The Access Assignment Channel (AACH) at the MAC level.
The AACH is primarily used for the following 2 purposes: On the traffic channel it conveys the ‘user marker’, indicating the intended destination of the down link slot and the allowed user of the uplink slot. Note: Up link and down link channels can be allocated to different calls, or a mix of circuit mode traffic in one direction and signalling, control or packet mode data, in the other direction. On signalling channels (control & user data), the physical broadcast block (AACH at the MAC level) is used to convey the access control elements (Access code & ALOHA) frame length. Independent information on each half slot can be conveyed in the AACH, or a mix of traffic in one direction and signalling in the other.
Frame 56.67ms
3
4
1
2
3
Time slot 14.167ms 510 modulation bits
4
1
Downlink
1
2
3
4
1
2
3
Uplink Carrier
SSN 1 SSN 2
Sub-Slot (Uplink only) 7.08ms = 255 modulation bits (1 bit = 27.78µs)
This describes an allocated time slot of a radio carrier duplex pair. There are 3 types of physical channel: •
Control (Physical) Channel.
•
Traffic (Physical) Channel.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:27-2 Nr.: 6866500U01-D Author: Bryan Simcock
•
27.2.
Unallocated (Physical) Channel.
Control Channel Each cell (base station) will have one allocated Control Channel (CC) and is always slot 1 of the first Tx/Rx carrier. This CC is used for call set up, SDS messaging, system management and passes allocated traffic channel information to subscriber units during call set up. Due to the interconnectivity of the base station, the CC passes information for all the Tetra Carriers of the cell. The cell may be configured (in Compact Tetra this is automatic) to enable slot 1 of its other base station transceivers to become the CC if succeeding transceivers fail.
CC
2
3
4
1
2
3
4
1
Tx/Rx 2
Tx/Rx 1
2
3
4
Tx/Rx 3
3 Tx/Rxers = 1 CC and 11 Traffic Channels
27.3.
Traffic Channel A slot becomes a traffic channel (TC) when a subscriber call has been allocated to it. Channels are defined as either: ●
A traffic channel when used for group or individual calls.
●
A data channel when used to pass data.
Note: It is possible to programme the system to allow it to dynamically assign data channels.
27.4.
Unallocated Channel This is a free channel available for call set up allocation, but while in this operational state, may be used to pass system information.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:27-3 Nr.: 6866500U01-D Author: Bryan Simcock
27.5.
Single Slot Full Duplex Operation Full duplex operation is provided when the corresponding slots of both an uplink and downlink are assigned for a call. Only 2 full duplex calls can be supported in any 1 timeframe by any Transceiver that does not have MCCH responsibility. This channel will also be carrying call related information as back ground signalling which may be monitored by, or relate to, other subscriber units. It can be used for telephony calls, full duplex individual calls or a 7.2kb/s bidirectional data connection.
27.6.
Multi Slot Full Duplex Operation Higher rate data applications are accommodated for by using consecutive time slots to provide a multi slot connection of up to 28.8kb/s. In order to support this, a subscriber unit must be full duplex capable and also be Multi-slot capable . Multi-slot packet data is not supported on Compact TETRA and no MS, as yet, supports multi-slot due to extreme heat dissipation issues.
27.7.
Single Slot Semi Duplex Semi duplex calls can be either individual or group calls. The time slot allocation is the same as that for single slot full duplex, but due to other signalling, it is possible that a different time slot might be used on the down link. I.e. Uplink time slot = 1 Downlink time slot = 3 or 4. Radios have full duplex capability and are able to receive in slots 1 & 2, but may be restricted to half duplex by an accessory.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:27-4 Nr.: 6866500U01-D Author: Bryan Simcock
Again, this channel will also be carrying call related information as back ground signalling which may be monitored by, or relate to, other subscriber units.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:27-5 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:27-6 Nr.: 6866500U01-D Author: Bryan Simcock
28.
Uplink Time Slot Structure A single time slot is capable of containing up to 8 ‘Burst’ structures, all of which are defined in the Tetra specification. The bursts are used to optimise the performance of the MS & BS. The Uplink Bursts are:
28.1.
•
The Control Uplink Burst.
•
The Linearisation Uplink Burst.
•
The Normal Uplink Burst.
•
Guard Period.
•
Training Sequence.
•
Tail Bits.
•
Blocks 1 & 2.
The Control Uplink Burst This occupies either sub slot (7.08ms) of a Time Slot and is used by the subscriber unit to carry control information to the base station transceiver being used for the call. 1
SSN1
2
3
4
1 2
3
SSN 2
Sub-Slot 7.08ms
34 Ramping & PA Linearisation 0.94ms
Compact TETRA COPYRIGHT Motorola 2002
4 15 Bit 4 84 30 84 Tail Scrambled Ext’d trng Scrambled Tail Guard Bits Period Bits Bits Bits Sequence Bits 0.42ms
Intro & System Overview R3_0.doc Page:28-1 Nr.: 6866500U01-D Author: Bryan Simcock
28.2.
The Linearisation Up link Burst This burst will always occur in sub slot 1 and is only used by the subscriber unit for transmitter PA linearisation.
1
2
SSN 1
3
4
1
2
3
SSN 2
Sub-Slot 7.08ms
240 Ramping & PA Linearisation
15 Bit Guard Period
6.66ms
28.3.
Normal Uplink Burst This carries either the subscriber signalling or control channel information to the base station transceiver being used for the call and takes up one complete Time Slot period of 14.167ms.
1
2
SSN 1
3
4
1
2
3
SSN 2
Sub-Slot 7.08ms
34 Ramping & PA Linearisation
4 Tail Bits
216 Scrambled Bits Block 1
22 Training Sequence Bits
216 Scrambled Bits Block 2
4 Tail Bits
14 Bit Guard Period
0.94ms
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:28-2 Nr.: 6866500U01-D Author: Bryan Simcock
Guard Period This period is used to allow for any timing misalignments, due to the increased propagation delays, caused as subscriber units move away from the base station. The Training Sequences There are 3 types of training sequence, one is used in the Control Uplink burst and the other two are used in the Normal Uplink burst. The Extended Training sequence used in the Control Uplink burst is a single fixed bit sequence and is only used for symbol synchronisation and equalisation. The training sequences used in the Normal Uplink burst not only provide symbol synchronisation and equalisation, but are also used to flag the different contents of the information blocks 1 & 2. The Tail Bits These are also used for equalisation, but their main purpose is to reduce the filter transient responses at the beginning and end of a burst and they are always coded 1100. Blocks 1 & 2 All the traffic is carried in these 216 bit blocks. The traffic is error protected and may also be encrypted. The maximum number of useful signalling bits carried by a normal burst is 432, but dependent on the type of information and the error correction, this may be far less.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:28-3 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:28-4 Nr.: 6866500U01-D Author: Bryan Simcock
29.
Downlink Time Slot Structure A single time slot is capable of containing up to 9 ‘Burst’ structures, all of which are defined in the Tetra specification. The Downlink Bursts are:
29.1.
•
The Normal Continuous Downlink Burst (NCB).
•
The Synchronisation Continuous Downlink Burst (SCB).
•
The Normal Discontinuous Downlink Burst (NDB).
•
The Synchronisation Discontinuous Downlink Burst (SDB).
•
The Linearisation Downlink burst (LB).
•
The Normal Training Sequence.
•
The Phase Adjustment Bits.
•
The Synchronisation Training Sequence.
•
The Broadcast Block.
The Normal Continuous Downlink Burst When a base station is in continuous transmission mode, it uses this burst structure to send either traffic or control information to subscriber units during a time slot period.
1 2
3
4
1
2 3
SSN1 SSN2 Sub-Slot 7.08ms
12 2 216 Trng Phase Scrambled Bits Seq. Adj. Block 1
22 216 Scrambled 2 Training 14 16 Bits or Phase Scr’d Sequence Scr’d PA Linearisation Adj. Bits Bits Bits Block 2
10 Trng Seq.
Broadcast Block
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:29-1 Nr.: 6866500U01-D Author: Bryan Simcock
29.2.
The Synchronisation Continuous Downlink Burst When a base station is in continuous transmission mode, it uses this burst structure to send synchronisation and control information to subscriber units in a time slot period.
1
2
3
4
1
2
3
SSN 1 SSN 2 SubSlot 7.08ms
2 12 Trng Phase Seq. Adj.
80 120 Freq. Scrambled Correction Synchro. Bits Bits Block 1
38 Synchro. Training Sequence
30 Scr’d Bits
216 Scrambled Bits or PA Linearisation Block 2
2 10 Trng Phase Seq. Adj.
Broadcast Block
29.3.
Burst Mode Power Ramping Both the base station and the subscriber unit must be able to transmit a controlled information burst during the time slot period. To do this, the transmitter power must ramp up, stabilise and provide constant power for the burst duration and then quickly ramp down. The ramp periods and stabilisation must not interfere with any transmissions in preceding or following time slots. Care must be taken to avoid fast ramping as adjacent and out of band interference will be generated by switching transients. The specification requires that these transients must be below –50dBc at 25kHz spacing from the centre frequency and they may also be limited by using a power mask.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:29-2 Nr.: 6866500U01-D Author: Bryan Simcock
29.4.
The Normal Discontinuous Downlink Burst If the base station’s operation is ‘Time Shared’, it uses a time slot to send this burst of traffic or control information to subscriber units
1 2
3
4
1 2
3
SSN1 SSN2 SubSlot 7.08ms 10 22 14 16 216 2 Ramp 2 Training Scr’d Scr’d rng Scrambled Bits Phase & Bits Bits Seq. Block 1 PA Lin Seq. Adj.
Bits
0.28ms
Compact TETRA COPYRIGHT Motorola 2002
2 216 Scrambled 8 2 Bits or PA Phase Trng Guard Linearisation Adj. Seq. Period Block 2
Broadcast Block
Intro & System Overview R3_0.doc Page:29-3 Nr.: 6866500U01-D Author: Bryan Simcock
29.5.
The Synchronisation Discontinuous Downlink Burst If the base station’s operation is ‘Time Shared’, it sends this burst structure, containing synchronisation and control information, to subscriber units in a time slot period.
1
2
3 4
1 2
3
SSN1 SSN2 SubSlot 7.08ms
10 Ramp & PA Lin.
216 120 2 2 80 30 Scrambled Bits Scrambled 38 2 12 Phase Trng Freq. or PA Synchro. Synchro. Scr’d Phase Trng Adj. Seq. Training Correction Bits Linearisation Bits Seq. Adj. Sequence Bits Block 2 Block 1 Broadcast Block
0.28m
29.6.
8 Guard Period
The Linearisation Downlink Burst This replaces Block 2 of either the Normal Downlink Burst (NDB) or the Synchronisation Continuous Downlink Burst (SCB) and is used by the base station to linearise its own PA.
29.7.
The Normal Training Sequence There are 3 types of training sequence used in the Normal Downlink burst (NDB). The first two training sequences not only provide symbol synchronisation and equalisation, but are also used to flag the different contents of the information sent in blocks 1 & 2. When the base station is in continuous transmission mode, the whole of the third type of sequence is used between bursts, but it is only partially used when the base station is in time sharing operational mode.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:29-4 Nr.: 6866500U01-D Author: Bryan Simcock
29.8.
Phase Adjustment Bits No matter what the content of the blocks, these bits provide a known phase relationship between the different sequences of the burst.
29.9.
Synchronisation Training Sequence This is a single, fixed 38 bit sequence and is used for both synchronisation and equalisation purposes.
29.10.
The Broadcast Block This is set by Layer 2 and contains the assignment information of the Uplink and Downlink slots.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:29-5 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:29-6 Nr.: 6866500U01-D Author: Bryan Simcock
30.
Transmission Power Levels The Tetra power levels are an average taken from the scrambled bits of one transmission burst. There are 4 nominal power classes (1-4) for Tetra subscriber units. Variable power control is available on subscriber units and dependent upon product, can have ranges from levels 1 to 7 where level 7 = 32mW and level 1 = 30W. Class 1 mobiles only have access to all 7 power levels. There are 10 nominal power classes for the Tetra base station equipment, ranging from class 1 = 40W (46dBm) to class 10 = 0.6W (28dBm). The power output of any base station is dependent upon the license and expected coverage with due regard to interference.
30.1.
Mobile Station (MS) Output Power Levels Any of the following power classes and levels may be supported by subscriber units. Step Level
Power
7
45dBm
6
40dBm
5
35dBm
35dBm
4
30dBm
30dBm
3
25dBm
2
20dBm
1
15dBm
Power
Nominal
Class
Power
1 (30W)
45dBm
2 (10W)
40dBm
3 (3W) 4 (1W)
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:30-1 Nr.: 6866500U01-D Author: Bryan Simcock
30.2.
Base station Output Power Levels Note: Compact Tetra supports Power Class 4 (10W)
Compact TETRA COPYRIGHT Motorola 2002
Power Class
Nominal Power Per Carrier
1 (40W)
46dBm
2 (25W)
44dBm
3 (15W)
42dBm
4 (10W)
40dBm
5 (6.3W)
38dBm
6 (4W)
36dBm
7 (2.5W)
34dBm
8 (1.6W)
32dBm
9 (1.0W)
30dBm
10 (0.6W)
28dBm
Intro & System Overview R3_0.doc Page:30-2 Nr.: 6866500U01-D Author: Bryan Simcock
31.
Communication Channels Logical Channel. This is defined as a logical communication pathway between 2 or more parties and it represents the interface between the radio link protocol and the user. There are 2 types of logical channel: 1. The traffic channel. This carries circuit switched speech or data. Vocoded speech is carried at 4.8kbps and data is carried at the following rates (determined by the level of error correct used): •
2.4kbps (highest level of protection)
•
4.8kbps
7.2kbps Traffic channels use the normal Burst structure for both the Uplink and Downlink traffic. •
31.1.
Traffic Channel Assignment Traffic Channel Vocoded Speech – U/D
Data 7.2kbps – U/D
Data 4.8kbps – U/D
Data 2.4kbps – U/D
2. The control channel which carries user information as packet switched data and signalling messages. Control channels are divided into five main sub categories: •
Broadcast control channel.
•
Linearisation channel.
•
Signalling channel.
•
Access assignment channel.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:31-1 Nr.: 6866500U01-D Author: Bryan Simcock
Stealing channel. Note: Some of these may be sub-divided to provide further information. •
31.2.
The Broadcast Control Channel This always uses slot 1 of both the Uplink and Downlink time slots of the controlling transceiver of a base station. It broadcasts general system information to all mobile subscriber units and is further sub divided into the following: The broadcast network channel which carries network information. The broadcast synchronisation channel that carries timing and scrambling information.
31.3.
The Linearisation Channel This has 2 categories: The base station linearisation channel, which is Downlink only and used by the base station to linearise its transmitter. The common linearisation channel, which is Uplink only and is used by all subscriber units to linearise their transmitters.
31.4.
The Signalling Channel This is shared by all subscriber units and carries messages for both individual and groups of subscribers; it provides the following 3 signalling format categories: The full size signalling channel, this is bi-directional and uses Blocks 1 & 2 of a normal burst in either the control or traffic channels. The half size Downlink signalling channel is used for sending half size signalling messages and uses Blocks 1 & 2 of a normal burst in either a control, traffic or unassigned channel. The half size Uplink control channel is used for sending half size messages via the control Uplink Burst in either of the control or traffic channels.
31.5.
The Access Assignment Channel This is used to pass the Uplink and Downlink slot assignment information. The information is only passed in the Broadcast Block of all Downlink Bursts.
31.6.
The Stealing Channel This is always associated with a traffic channel.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:31-2 Nr.: 6866500U01-D Author: Bryan Simcock
It will temporarily ‘Steal’ part of a traffic channel’s signalling capacity to pass fast signalling messages as and when required. If it steals from a traffic channel that is being used for semi duplex operation, it is then, in effect, only unidirectional.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:31-3 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:31-4 Nr.: 6866500U01-D Author: Bryan Simcock
32.
Control Channel Assignment Control Channel Broadcast Control Channel Broadcast Network Channel - D Broadcast Synchronisation Channel - D Linearisation
Common Linearisation Channel - U Base Station Linearisation Channel - D
Signalling
Full Size Signalling Channel – U/D Half Size Signalling Downlink Channel - D Half Size Signalling Uplink Channel - U
Access Assignment Channel
Stealing Channel
32.1.
Control Channels There is a need for the system to support general signalling as well as supporting call set up, clear down and the regulation of traffic, especially at times of peak loading. Each Tetra cell will have a certain traffic capacity which is dependent upon the number of carriers available at its base station. To control this traffic, each base station will have a control channel, time slot 1 of its Transceiver number 1, dedicated to the control of all the subscriber units in its coverage area. There are two types of control channel and both are always referred to as the Main Control Channel (MCCH):
32.2.
•
The common control channel.
•
The dedicated control channel.
The Common Control Channel This is used by the base station for the following reasons: •
The transmission of system information.
•
The transmission of synchronisation information.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:32-1 Nr.: 6866500U01-D Author: Bryan Simcock
32.3.
•
Network paging.
•
For the linearisation of both the base station and subscriber units’ transmitters.
•
By subscriber units to access the different system features.
The Dedicated Control Channel This used by both the network and subscriber units to exchange signalling that is exclusive to a particular connection, i.e. registration. Which of the 2 types of control channel, the dedicated or common, that will be used, is passed to the subscriber unit via a dedicated block in the down link transmission.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:32-2 Nr.: 6866500U01-D Author: Bryan Simcock
33.
Traffic Control The ETR 300-1 recommends that a single control channel should be able to support 16 to 20 traffic channels (4 or 5 Carriers). A base station that is supporting light to medium traffic, in its cell, will operate in Normal Mode with all the common and dedicated signalling taking place in slot 1. If the traffic becomes to heavy such that the control channel does not have the capacity to support this increase, then the control channel will extend into another time slot. This is called the Secondary Control Channel and when this happens, all subscriber units in the cell must be informed of the new control channel and how it is to be used. The system may also divide the subscriber units equally between the 2 control channels, or it may only use the secondary control channel for either packet data or additional call set up signalling.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:33-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:33-2 Nr.: 6866500U01-D Author: Bryan Simcock
34.
Mobility Management From the moment users power up their radios they have an expectation of seamless roaming and instant communications. All types of network offer this service and Tetra networks are no different. What is different is the way this service is managed and performed by the system and subscriber units. The Tetra subscriber units are helped in their search for control channels by base station broadcast messages on their MCCH. The control channel information of adjacent cells is broadcast by each base station and instead of wasting time doing a back ground hunt that covers all the frequencies held in its channel lists, the mobile stations are now told which channels to scan for the acquisition of adjacent cells.
34.1.
Cell Acquisition at Power Up Once a subscriber unit is powered up it will go though several procedures to acquire a control channel, especially if it is being powered up for the first time on the system. Assuming this is the case, then the radio will scan its list of control channels looking for a strong enough transmission from which it can synchronise and obtain adjacent cell information. It will then register and send a Location Update which informs the network of its present position. Once this occurs, it will continue to check the control channels of the adjacent cells for the best signal as part of the ongoing process.
34.2.
Channel Selection The radio must select the control channel that offers the best quality of service. This decision is based on the received RSSI and a calculation using defined cell selection parameters (C1) which are obtained from the system information transmitted on the Broadcast Channel. Once the decision is made, the radio registers with the system by sending a location update message which tells the system of its activation and its cell location. C1 is based on the following criteria: The RSSI from the received cell. Pms – the maximum transmit power of the subscriber unit. RxLev_Access_Min. – The minimum usable signal strength received by the subscriber unit.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:34-1 Nr.: 6866500U01-D Author: Bryan Simcock
MS_TxPwr_Max_Cell – The maximum allowed subscriber unit transmit power. Max – Notation means take the highest of the expressions (0 or MS_TxPwr_Max_Cell) used in the bracket. Where C1 = (RSSI - RxLev_Access_Min) - (Max(0 or MS_TxPwr_Max_Cell Pms))
34.2.1.
RSSI - RxLev_Access_Min = > 0 The RxLev_Access_Min entry field in the BSC configuration file is used to define the talk in/out path of a cell. It is the lowest allowed received signal level at the subscriber. As soon as the subscriber receives this level of signal it is a usable cell. The entry level in this field is from 1 to 15 and represents signal levels from -125dBm to –55dBm in 5dBm steps. i.e. 1 = -125dBm & 15 = -55dBm
34.2.2.
Radio Improvable The quality of radio service becomes improvable when the service quality of a neighbouring cell exceeds that of the present cell by a certain amount. When this occurs the radio may select the new cell. If the radio is in the idle mode and the quality is Improvable it will reselect. If the radio is in a call, it may not reselect, but will wait until the present cell is Relinquishable.
34.2.3.
Radio Relinquishable. The service of a cell becomes Radio Relinquishable when it falls below a certain level and the quality of a neighbouring cell downlink exceeds that of the present cell by a specific amount. When this occurs, the radio will use C2 to justify the switch. C2 is based on the transmitted system information in the Broadcast Channel which is set as part of the system optimisation. The transmitted information is the fast and slow values for both the Reselect Hysteresis and the Reselect Threshold.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:34-2 Nr.: 6866500U01-D Author: Bryan Simcock
34.3.
Cell Optimisation Ideal Cell Coverage.
FAST_RESELECT_HYSTERESIS (-80dBm) Acts up to 20dBm above FAST_RESELECT_THRESHOLD FAST_RESELECT_THRESHOLD Theoretical Point at which Service becomes Radio Relinquishable –100dBm (RSSI).
RXLEV_ACCESS_MIN = 4 (-110dBm) Direction of Travel
SLOW_RESELECT_HYSTERESIS setting acts either side of and is centered on the SLOW_RESELECT_THRESHOLD_ABOVE_FAST setting
34.4.
SLOW_RESELECT_ THRESHOLD _ABOVE_FAST Theoretical Point at which Service becomes Radio Improvable –90dBm (RSSI only).
Acquiring an Adjacent Cell As the users move through the cell, their radios not only monitor the control channel down link for paging messages (call set up, SDS messages etc) and system information, but it also monitors the RSSI level. The system information also provides the radio with adjacent cell control channel information and the radio uses this information for its back ground hunt. As it scans this information it will become apparent that the signal strength of one channel will be increasing as the signal strength of its present control channel is decreasing. There will then be a point in time, which has relevance to the radio’s position in its present cell, when it will switch to the control channel of the new cell. To enable the radio to make the decision to switch, it continually uses both the C1 & C2 calculation to compare the control channel signals of its present and proposed cell.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:34-3 Nr.: 6866500U01-D Author: Bryan Simcock
34.4.1.
C2 – Radio Improvable Cell reselection is initiated when the serving cell becomes radio improvable. (C2(NCell) > (C1(SCell)+SRH)) > 5sec (C1(SCell) < SRT) > 5sec Note: The above conditions must be met simultaneously.
* Note: These levels are defined in the bssfactoryparams.txt file.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:34-4 Nr.: 6866500U01-D Author: Bryan Simcock
34.4.2.
C2 – Radio Relinquishable (C2(NCell) > (C1(SCell)+FRH)) > 5sec (C1(SCell) < FRT) > 5sec Note: The above conditions must be met simultaneously.
34.4.3.
C2 - Radio Usable Reselection can be delayed if the new cell does not meet the switch criteria and a situation may occur where the cell is Radio Relinquishable, but no neighbouring cell meets the radio usable criteria, in which case the cell with the highest C2 is selected. (C2(NCell) > (FRT+FRH)) > 5sec
34.4.4.
*Typical System Settings for Cell Coverage The Hysteresis settings allow for cell hand over when the serving cell signal quality is poor due to interference. /base-station/BLE/SLOW_RESELECT_THRESHOLD_ABOVE_FAST = 5; /base-station/BLE/SLOW_RESELECT_HYSTERESIS = 5; /base-station/BLE/FAST_RESELECT_THRESHOLD = 5; /base-station/BLE/FAST_RESELECT_HYSTERESIS = 10; settings are based on the /base-station/SYSINFO/RXLEV_ACCESS_MIN = 4; Ideally all cells would have the same settings with the RXLEV_ACCESS_MIN levels being the same, but due to the topography and other factors this is not the case. the RXLEV_ACCESS_MIN setting is the weakest signal that an MS is allowed to receive on a cell (farthest point of the talk in/out path) say -110dBm. We know that when the received signal is getting down to this level its quality MAY also be poor due to interference, so 2 safeguards ensure that we hand over to another cell before the signal strength/quality gets down to this level. The safeguards are: The FAST_RESELECT_THRESHOLD setting which defines the signal level above the RXLEV_ACCESS_MIN level setting where, with an acceptable quality
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:34-5 Nr.: 6866500U01-D Author: Bryan Simcock
signal being received from the active cell the MS will hand over to the neighbour cell. The FAST_RESELECT_HYSTERESIS setting that enables the MS to select another cell when the quality of the received signal suddenly becomes poor (if the neighbouring cell signal quality is good) and is a level above the FAST_RESELECT_THRESHOLD. Normal cell hand over is controlled by the following: SLOW_RESELECT_THRESHOLD_ABOVE_FAST (RESELECT_HYSTERESIS) level setting, which is equal to the SLOW_RESELECT_THRESHOLD_ABOVE_FAST + the FAST_RESELECT_HYSTERESIS setting and this is the level above the RXLEV_ACCESS_MIN level. The SLOW_RESELECT_HYSTERESIS level allows for quality control and equates to a level either side of the SLOW_RESELECT_THRESHOLD_ABOVE_FAST level. All the level settings in the configuration files are numbers that relate to dBm tables. To enable the hand over where you want, it may be necessary to reduce the power of a cell, which may also be causing problems with other cells.
34.5.
MS Actions at Cell Reselection The subscriber unit may do any of the following actions as it moves into a new cell:
34.5.1.
•
Announced. • Type 1. • Type 2. • Type 3.
•
Unannounced.
•
Undeclared.
Announced As the MS moves into the new cell during a call, it informs the old cell that it is about to leave. The SwMI, on receiving this information may then broadcast late entry signalling on adjacent sites.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:34-6 Nr.: 6866500U01-D Author: Bryan Simcock
This increases the probability of the MS recovering the connections on the new site. There are 3 types of announced Reselection: Type 1 – The old cell provides the MS with the channel (frequency & time slot) that it will use at the new site. This gives a fast switching time with no discernable break in transmission. Type 2 – The MS tries to recover the connection via the control channel of its the new cell, which causes a short break in transmission as the connection is reestablished. The new cell informs the old cell of the move. Type 3 – If back ground scanning is not possible, the MS will suspend the connection so that it can scan, select a new cell and re-establish the link (0.5 – 3seconds).
34.5.2.
Unannounced There may be no need to inform the old cell that it is leaving if the MS is receiving a group call, or is unable to inform its old cell that it is leaving. The radio switches to the new site and monitors the main control channel for the following service information on the Broadcast Network channel: •
Subscriber Class supported (1 – 16).
•
Priority Cell indication (Y/N).
•
Tetra Circuit Mode data supported (Y/N).
•
Connection Orientated Network Protocol (CONP)/Sub-network Dependent Convergence Protocol (SNDCP) supported (Y/N).
•
Air Interface Encryption supported (Y/N).
•
Preferential Cell (MS Subscription).
•
Call in Progress (TCH or Sig.).
•
Cell Traffic Loading (Low, Medium, High or Unknown), sent on the BSCH.
The subscriber unit checks the calls in progress information and:
34.5.3.
•
If there are other radios in the call it will go to the traffic channel and rejoin the call.
•
If there are no radios in the call, it registers in that cell and gets allocated a traffic channel to rejoin the call with late entry procedure.
Undeclared If the MS is in the idle mode, it is able to switch to the new cell with out informing either cell. The Location Update sent by the MS is independent of cell reselection.
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:34-7 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:34-8 Nr.: 6866500U01-D Author: Bryan Simcock
35.
Miscellaneous
35.1.
Ethernet 10/100Base-T Straight Through Cable. This cable works with both 10Base-T and 100Base-T
Name
Pin
Cable Colour
Pin
Name
Tx +
1
White/
1
Tx +
Orange Tx -
2
Orange
2
Tx -
Rx +
3
White/
3
Rx +
Green 4
Blue
4
5
White/
5
Blue Rx -
6
Green
6
7
White/
7
Rx -
Brown 8
Compact TETRA COPYRIGHT Motorola 2002
Brown
8
Intro & System Overview R3_0.doc Page:35-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:35-2 Nr.: 6866500U01-D Author: Bryan Simcock
36.
Interoperability Test for Compact TETRA IOP is InterOPerability test of TETRA subscribers and systems from different manufacturer by an independent test house (Tele Danmark) Status from Mid 2002: Compact TETRA works with terminals from: Motorola, Nokia, Cleartone and Teltronics (Simoco/Sapura terminals have been tested successfully in another unofficial test.)
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:36-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:36-2 Nr.: 6866500U01-D Author: Bryan Simcock
37.
Motorola Terminals used for Compact TETRA All current Motorola TETRA terminals are tested and can be used on Compact TETRA. Currently, these include MTM700, MTP700 and MTH500. For details see the specific terminal documentations. Note that some feature available on the terminals may not be available on the Compact TETRA system.
Dash Mount MTM700
Standard Remote MTM700
Compact TETRA COPYRIGHT Motorola 2002
Databox MTM700
Desktop MTM700
MTP700
MTH800
MTH500
MTH650
Intro & System Overview R3_0.doc Page:37-1 Nr.: 6866500U01-D Author: Bryan Simcock
Intentionally Blank
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:37-2 Nr.: 6866500U01-D Author: Bryan Simcock
38.
Glossary of terms and abbreviations Base station A base station is one or more transceivers at a single site, which is under the control of a BSC (Base Station Controller) Base station controller A base station controller is a unit that controls all transceivers on one site and provides the interface to the other network elements. Trunked, trunking A method of traffic channel organization where channel is allocated automatically for each call transaction AI
Air Interface
ASCII
American Standard Code for Information Interchange
ASSI
Assigned Short Subscriber Identity
BS
Base Station
CLIP
Calling Line Identification Presentation
COTS
Commercial Off The Shelf
CSCI
Computer Software Configuration Item
DSP
Digital Signal Processor
ESN
External Subscriber Number
ETS
European Telecommunications Standard
ETSI
European Telecommunication Standards Institute
FDIC
Full-Duplex Individual Call
FTP
File Transfer Protocol
GPS
Global Positioning System
GSSI
Group Short Subscriber Identity
GUI
Graphical User Interface
HMI
Human-Machine Interface
HW
Hardware
IF
Interface
IOP
Interoperability, specifically, Tetra SwMI/MS interop.
IP
Internet Protocol
ISDN
Integrated Services Digital Network
ISSI
Individual Short Subscriber Identity
ITSI
Individual Tetra Subscriber Identity
ITU-T
International Telecommunications Union
LA
Location Area
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:38-1 Nr.: 6866500U01-D Author: Bryan Simcock
LAN
Local Area Network
LE
Late Entry
MCCH
Main Control Channel
MS
Mobile Station
MTBF
Mean Time Between Failures
PABX
Private Access Branch Exchange
PAMR
Public Access Mobile Radio
PEI
Peripheral Equipment Interface
PMR
Private Mobile Radio
PD
Packet Data
PSTN
Public Switched Telephone Network
PTT
Push-To-Talk
RF
Radio Frequency
SDIC
Semi-Duplex Individual Call
SDS
Short Data Service
SSDD
System/Subsystem Design Document
SSI
Short Subscriber Identity
SUM
Subscriber Management
SW
Software
TAI
TETRA Air Interface
TDMA
Time Division Multiple Access
TCP
Transmission Control Protocol
TETRA Terrestrial Trunked Radio TMA
Tower-Mounted Amplifier
TPI
Talking Party Identification
TX
Transmitter, Transmission
UGC
Unacknowledged Group Call
VAC
Volt Alternating Current
----- END OF DOCUMENT -----
Compact TETRA COPYRIGHT Motorola 2002
Intro & System Overview R3_0.doc Page:38-2 Nr.: 6866500U01-D Author: Bryan Simcock
View more...
Comments
