TETRA Air Interface

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 that this course will satisfy their complete requirements, while for others it will provide a steppingstone to further research and study based on primary material and associated Wray Castle courses. This course is also very 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 ETSI documentation relating to the TETRA air interface
• describe the functions of each key function within the TETRA air interface protocol stack
• identify the endpoints of the standardized TETRA air interface and relate these to the protocol stack
• list and describe the realistic performance of the teleservices and bearer services available in TETRA
• describe the data capabilities of TETRA
• justify and explain the operation of π/4DQPSK as the TETRA modulation scheme
• describe TETRA radio transmission and reception performance characteristics
• describe the physical layer structure in terms of bursts, timeslots, frames and multiframes
• list the TETRA physical and logical channels and identify their mapping relationships
• describe the functions of the MAC layer in relation to call procedures and error protection coding
• describe the functions of the MLE in controlling TETRA air interface activity and the LLC in handling media flow across the air interface
• describe the functions of CMCE and the MM entity in key signalling scenarios
• describe the capabilities, procedures and air interface structures for direct mode operation in TETRA

In addition to gaining a good understanding of the TETRA air interface and its capabilities, 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   Air Interface Capabilities and Structure
The TETRA standards
The TETRA standard interfaces
TETRA identities
TETRA bearer services
TETRA teleservices
Supplementary services
Public Safety Partnership Project (PSPP)
TETRA air interface protocol stack

Section 2 – 2 hours   TETRA Radio and Modulation
TETRA frequency allocation
Modulation and demodulation
Square waves
Quadrature Phase Shift Keying (QPSK)
Coherent and non-coherent demodulation
π/4 Differential Quadrature Phase Shift Keying (π/4DQPSK)

Section 3 – 2 hours   Physical and Logical Channels
Time Division Multiplexing (TDM)
Physical channels
Burst structures
Logical channels
Traffic Channels (TCH)
Control Channels (CCH)
The Broadcast Control Channel (BCCH)
The Linearization Channel (LCH)
TETRA CCHs
MCCH sharing
Carrier sharing
Logical channels and packet data
Logical to physical channel mapping
TETRA transmit power levels
MS receiver classes

Section 4 – 1.5 hour   The MAC Layer
Medium Access Control (MAC) layer
MAC sublayers and related logical channels
The lower MAC layer functions
Block coding in the lower MAC
The convolutional process
The interleaving process
Logical channels and error protection
The upper MAC layer
MAC signalling
Signal strength measurements
The C1 and C2 calculation
Using C1 and C2
Upper MAC layer procedures
Random access
Random access procedure
MAC-ACCESS
SwMI response to random access
MAC-RESOURCE
Mobile adaptive power control
MS open loop power control
Mobile closed loop power control

Section 5 – 1.5 hours   Logical Link Control (LLC)
Logical Link Control (LLC) layer
LLC services
LLC procedure
LLC basic link
Operation of basic link data transfer
Examples of basic link Protocol Data Units (PDUs)
Advanced link
Advanced link set-up
Selective retransmission

Section 6 – 2 hours   Network Layer
TETRA network layer location
Mobile Link Entity (MLE)
Circuit Mode Control Entity (CMCE)
Individual call set-up
Supplementary Service (SS) protocol
SS PDU format
Short Data Service (SDS) protocol
PDUs for CC, SS and SDS
TETRA Mobility Management (MM) protocol
Authentication and ciphering
Authentication Key (K)
MS authentication
Network authentication
Encryption
Authentication signalling sequence – MS by SwMI

Section 7 – 2 hours   Direct Mode Operation (DMO)
TETRA Direct Mode Operation (DMO)
Frequency of operation
The DM channel
Air interface signalling procedures
DMO services
DMO equipment types
The Dual Mode Mobile Station (DM-MS)
Dual Watch DMO (DW-MS)
DMO Repeater (DM-REP)
DMO Gateway (DM-GATE)
Direct Mode Repeater/Gateway Combination (DM-REP/GATE)
DM-MS protocol stack
DMO security features
DMO authentication and confidentiality
Managed DMO (M-DMO)

This course has been developed for engineering staff requiring detailed knowledge of a specialist area of technology. It assumes some underlying knowledge in broader, related topic areas on which the detailed content is built. 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.

Post-Course Support

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.

Those wishing to extend their technical knowledge into other mobile systems can do this through our courses covering technologies such as GSM, GPRS or UMTS. We also offer planning and optimization courses in other technologies, which are useful for those working on TETRA systems. Those involved with technologies relating to TETRA operation should also consider our courses covering IP and MPLS.

The Terrestrial Trunked Radio (TETRA) system has been designed to meet the varied requirements of private mobile users. This requires a fully scalable air interface supporting multiple call types and multiple media types. This very broad capability requirement for a single technology results in an extensive technical specification.

This Wray Castle course provides a detailed description of the key aspects of the radio link between a TETRA mobile and a TETRA base station. The course includes higher-layer signalling, protocol interactions and media processing aspects as well as lower-layer functions such as modulation, radio performance and channel coding. All commonly used TETRA air interface identities, capabilities and operational scenarios are covered. TETRA voice and data capabilities are also explained with consideration given to security and performance characteristics.

Prerequisites

In order to achieve the maximum benefit from attending this course, it is recommended that you are familiar with the architecture and general operation of a TETRA network. This is most readily obtained through attendance on our TETRA System Overview course.