LTE Air Interface

Overview

The adoption of the LTE air interface, E-UTRA, is a long-term evolutionary path for many network operators. It is therefore vitally important that engineers and technical staff have the knowledge necessary to plan for its introduction. This Wray Castle course is designed to provide engineering and technical management staff with a technical description of the technologies and techniques employed in E-UTRA, and to explain how it operates within an EPS network.

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

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

• explain the significance of the EPS and the LTE air interface in the continued progression towards converged telecommunication and entertainment services.
• characterize the performance aims and capabilities of the LTE air interface and identify the network elements and interfaces that form the EPS
• describe how data packets for traffic and service-related signalling are mapped into and carried through appropriate EPS bearers relating to a single UE
• explain a number of options for handling real-time services in, or in association with, the EPS
• describe the key functions and procedures provided by the RRC protocol and relate this to UE activity
• describe the key functions, operation and structures for the layer 2 protocols PDCP, RLC and MAC including flow control, scheduling, traffic prioritization, channel mapping and security functions
• define the property of orthogonality in sine waves and relate this to the operation of an OFDMA-based radio interface.
• explain how QAM modulation, the Fourier Transform, channel adaptation and MIMO are brought together in the realization of the OFDMA downlink and SC-FDMA uplink for the LTE air interface
• describe the physical layer structure and implementation options for E-UTRA
• describe the operations cell selection/reselection, random access, resource scheduling, measurement control, handover control and power control

In addition to gaining a good understanding of the LTE air interface, 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 a system’s capabilities effectively 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   Introduction to LTE
Broadband access with LTE
Architecture terminology
LTE development and design goals
LTE standards development
LTE key technologies
Access networks and the eNB (evolved Node B)
X2 interface
The EPC (Evolved Packet Core)
S1 interface
Evolved packet core ‘S’ interfaces
Data rates and services
E-UTRA protocols

Section 2 – 1.5 hour   UE Bearers and Connectivity
The EPS as an IP-CAN
EPS bearer QoS class identifiers
Allocation and retention priority (ARP)
QoS levels
EPS bearer composition and establishment
EPS area and subscriber identities
LTE state management and EPS service concepts
EPS initial attach and IMS registration
Tracking area update and paging
Service requests
IMS connection establishment
CS fallback call setup
CS service provision via a GANC
S1 interfaces for HeNBs (Home eNB)

Section 3 – 2 hours   OFDM Principles
Defining radio carrier orthogonality
Resilience to time dispersion and multipath fading
Principles of QAM
The Fourier Transform
The OFDM transmitter and receiver
The cyclic prefix
Scalability in OFDM
OFDMA resource allocation strategies
Channel adaptation and Turbo coding
OFDM peak to average power ratio
SC-FDMA principles of operation
MIMO concept and benefits
Multi-user MIMO

Section 4 – 2.5 hours   Physical Layer Structure
Channel bandwidths and subcarriers
Frequency bands and radio channel organization
OFDMA parameter summary
Modulation and error protection
Physical channels
The physical layer timing unit
Type 1 and Type 2 frame structure
Resource blocks
Downlink cell and UE-specific reference signals
Uplink demodulation reference signals
Uplink sounding reference signals
Synchronization signals
PBCH transmission
Downlink control channels and resources
Resource allocation options
PUCCH resource allocation
Resource allocation for PUSCH and PRACH

Section 5 – 2 hours   Layer 2 Protocols
L2/L1 channel mapping
PDCP architecture and PDU formats
PDCP sequence numbers in handover
PDCP message integrity protection
PDCP ciphering
RLC general functions and modes
RLC UM and AM frame structures
RLC retransmission and resegmentation
MAC general architecture and PDU structure
Scheduling functions and prioritized bit rates
RACH procedure for MAC
RNTI types
Downlink HARQ principles and operation
Management of DRX for connected mode

Section 6 – 1 hour   Radio Resource Control
RRC functions and states
RRC I-RAT state transitions
Signalling radio bearers
System information broadcasting and paging
RRC connection establishment
UE capability enquiry
Security mode setting
Data radio bearer establishment
Measurement configuration
Intra-LTE handover
Handover from LTE (IRAT)
NAS information transfer

Section 7 – 2 hours   Lower Layer Procedures
Cell search procedure
PLMN selection
Idle mode
Cell selection
Cell reselection
DRX operation
E-UTRA radio measurements
Measurements for RRC connected mode
Measurement gaps
Trigger events for E-UTRA
Uplink power control
Timing advance
CQI reporting and reporting options
MIMO options for LTE

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.

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.

Delegates involved in network planning and optimization may progress onto Cell Planning for LTE Networks or Introduction to LTE E-UTRA Optimization. It may be useful for some delegates to combine this course with either one, or both, of the Flexicourse options for the LTE RAN and LTE EPC. Others may use this course as part of a more complete study including the full LTE Radio Access Network or LTE Evolved Packet Core Network courses.

Since its introduction, UMTS has evolved considerably, especially with HSPA and the beginnings of a move towards an all-IP architecture. Release 8 specifications introduce the Evolved Packet System (EPS) – the next very important evolutionary step for 3GPP-based networks. The EPS includes a new access network and the EPC (Evolved Packet Core). This course focuses on the structure and operation of the new LTE air interface, E-UTRA.
E-UTRA improves on UMTS air interface performance and efficiency
with higher data rates, reduced latency and improved spectral
efficiency on a flatter IP-based architecture.

This detailed two-day course comprises seven sections. The first section provides delegates with an introduction to the E-UTRAN. This is followed by a more detailed section introducing service provision, connectivity and EPS bearer concepts. Next, the functionality and procedures for the RRC protocol are examined. This is followed by a section covering the functions, procedures and structures of the layer 2 protocols PDCP, RLC and MAC. The focus then turns to the physical layer; one section is used to introduce the technologies and techniques that enable OFDM operation and a second describes the specific structure of the LTE physical layer. The final section draws together the complete protocol stack in order to describe UE activity.

Prerequisites

Delegates attending this course are assumed to have a good understanding of radio systems and protocol concepts. Ideally, delegates will already have some knowledge of the EPS network and its architecture. Experience and knowledge of the GSM/UMTS air interface and GSM/UMTS network operation would also be beneficial.