TETRA System Overview

Overview

This course is primarily designed for engineers working for equipment vendors and for network operators who are involved in equipment design, manufacture, network planning, network optimization, strategy determination or deployment of TETRA technology. Some may find this course is all they need to know; for others it will provide a steppingstone to further study on an appropriate Wray Castle Technical Level 3 course.

This course is also useful for engineers and scientists working in areas related to TETRA operation. This includes base station management, antenna or transmission line design, Government security or forensic work, service developers, legal professionals supporting operators or local authorities, support staff and those in technical management roles.

On completion of this course the delegate will be able to:

• identify potential users and services that are suited to TETRA’s capabilities
• list the standardized TETRA interfaces and identify the location and types of non-standardized interfaces that may be required
• use traffic theory to justify the use of a trunked radio system in a range of mobile radio scenarios
• list and describe the realistic performance of the teleservices and bearer services available in TETRA
• describe the circuit-switched and packet-switched data capabilities of TETRA including TETRA Advanced Packet Services (TAPS)
• explain how the TETRA radio channel can be adapted in terms of error protection for the highest reliability
• relate cellular radio principles to the design of large-scale TETRA networks
• describe the fundamental radio characteristics of TETRA base station and mobile station equipment
• discuss digital signal processing techniques in TETRA systems and identify where they are applied
• describe network architecture possibilities for TETRA and state the functions of key network elements
• describe the general structure and operation of the TETRA air interface
• identify and characterize the mobility management functions that are required in a TETRA network
• describe the capabilities and options for direct mode operation in TETRA

In addition to gaining a good understanding of the TETRA system, attending this course will enable the delegate to deliver operational improvements and generate cost savings or reduce project timelines by:

• improving network design, planning, operations and maintenance
• avoiding the laborious search through specifications, standards and white papers, while benefiting from a
• practical analysis and interpretation of such documentation by experienced engineers
• knowing better where to look to accelerate research and fact finding and facilitate earlier project completion
• improving the equipment procurement process by better analysis and challenge of technical specifications and supplier responses, thus giving greater certainty to on-target performance and value-for-money purchasing
• shortening the learning curve and speeding productive inputs from new team members and freeing more experienced employees’ time
• evaluating better a system’s capabilities through improved knowledge, leading to superior operations and maintenance performance
• providing greater confidence in the sale of equipment by anticipating customers’ technical requirements and
• being able to promote relevant superior equipment performance

and, after the course, Wray Castle’s unrivalled post-course support comes into effect.

Section 1 – 1 hour   TETRA Introduction
TETRA development work
Users of TETRA
The TETRA standards
The TETRA standard interfaces

Section 2 – 2 hours   Trunked Radio Systems and Traffic Principles
Trunked radio systems
The benefits of trunking
Trunked system facilities
Traffic principles
Offered, carried and blocked traffic
Grade of Service (GoS)
The Erlang
Trunking efficiency (channel utilization)
Erlang’s traffic models
Trunking gain

Section 3 – 1.25 hours   TETRA Services
TETRA bearer services
Data rates and protection
TETRA teleservices
TETRA data services
TETRA packet data solutions
TETRA Enhanced Data Service (TEDS)
Supplementary Services (SS)

Section 4 – 1.5 hours   Cellular Principles
Radio resource sharing
Providing radio coverage
Traditional coverage methods
The cellular philosophy
Frequency reuse
Adjacent channel interference
Co-channel interference
Interference in cellular systems
Carrier to Interference Ratio (C/I)
Interference rejection
Acceptable quality in cellular systems

Section 5 – 1.5 hours   An Introduction to Digital Communications
Why go digital?
Security
Integrated services
Comparison of analogue and digital systems
Pulse Code Modulation (PCM)
TETRA codec
Speech decoding
Noise in digital systems
Audio channel noise
Channel cut-off

Section 6 – 1 hour   Network Architecture
General trunked network architecture
Call processing
TETRA user terminals
Receiver types and performance
Reference sensitivity
The Line Station (LS)
Transmit power levels
Mobile adaptive power control
A medium-sized TETRA system
A nationwide TETRA network
The Inter-System-Interface (ISI)
The LS interface
The gateway interface
Public Switched Telephone Network (PSTN)
Integrated Services Digital Network (ISDN)
Public Data Networks (PDN)

Section 7 – 1 hour   The TETRA Radio Interface
TETRA frequency allocation
Multiplexing on the radio channel
Time Division Multiple Access (TDMA) in TETRA
TETRA physical channels
Duplex/simplex working
Full duplex operation single-slot
Full duplex operation multislot
Semi-duplex single-slot
Semi-duplex multislot
Logical channels
Control channels in TETRA
Normal Control Mode (NCM)

Section 8 – 1.25 hours   TETRA Mobility Management
Mobility management
Procedures at switch-on
Cell selection
Idle mode
Cell reselection and reselection types

Section 9 – 1.5 hours   Direct Mode Operation (DMO)
TETRA Direct Mode Operation (DMO)
Frequency of operation
Frequency efficient mode
DMO services
Teleservices
DMO bearer services and intrinsic services
DMO equipment types and connections
Managed DMO (M-DMO)

This course has been developed for staff requiring a broad overview of a technology area. It assumes some underlying technical ability and may require general knowledge of telecommunications and of network operation. It also assumes general engineering skills and knowledge appropriate to the course topic.

Along with a paper copy of comprehensive course notes the delegate will receive an electronic version on CD. This provides delegates with an easily transportable and fully searchable reference tool, including all the colour detail of the course presentation.

Following attendance on any Wray Castle course the delegate will automatically become eligible for free post-course support. If a delegate has any questions relating to the course content, this service puts the delegate in direct e-mail contact with a Wray Castle expert.

This course is designed for instructor-led training. The practical and/or complex nature of the course is best delivered in a class where the Wray Castle expert trainer can demonstrate and explain the content using a variety of specialist delivery techniques.

For those wishing to extend the depth of their technical knowledge in TETRA the Wray Castle Technical Level 3 TETRA Air Interface course is recommended. Those involved with technologies relating to TETRA operation should also consider our courses covering IP and MPLS. Delegates may also benefit from other Wray Castle Technical Level 2 courses covering mobile technologies such as GSM, GPRS and UMTS.

The Terrestrial Trunked Radio (TETRA) system has been designed to meet the varied requirements of private mobile users. This encompasses networks as diverse as basic radio-to-radio communication between two users and a fully data capable switched infrastructure providing national coverage for thousands of users. This very broad capability requirement for a single technology results in an extensive technical specification.

This Wray Castle course provides a wide ranging and easy to follow tour of all the important features, technologies and operational modes in a TETRA system. The course includes descriptions of defined aspects such as the radio link and configuration possibilities; all of this based on the ETSI specifications. Additionally, undefined aspects such as the potential structure and features of the supporting switching infrastructure, transmission architecture, potential user organizations and service possibilities are also covered.

Prerequisites

In order to achieve the maximum benefit from this course, it is recommended that delegates are familiar with the architecture and general operation of typical VHF or UHF mobile networks. Some understanding of radio techniques would also be useful. However, most people with an ability to understand technical information will benefit from this course.