LTE Signalling

Course overview:

The course contains detailed information about the interfaces, protocols and procedures of the Evolved Packet System (EPS) with evolved radio access network (E-UTRAN). Special attention is given to the layer 3 protocols defined for NAS and X2, S1, S11, S5-interfaces. The radio interface layer 3 and layer 2 protocols as well as the physical layer control channels are also covered. The EPS bearer and QoS concepts are introduced. The scheduling mechanisms and Hybrid-ARQ (HARQ) functionality are described. Message flows for selected important signalling procedures are investigated step by step. The course also contains a description of some expected interworking scenarios (e.g. E-UTRAN to UTRAN handover). Basic message-level traffic cases are shown throughout the course to demonstrate important functions and concepts.

Pre-requisites:

General knowledge about the architecture, terminology and modes of operation of the E-UTRA radio interface is recommended. Knowledge about UMTS High Speed Packet Access is useful. For required background knowledge, the Apis course LTE/SAE System Overview (or equivalent) is recommended.

Course contents

EPS Introduction

• Mobile network evolution: GSM to EPS

• New network nodes, areas, bearer concepts and identity numbers introduced for EPS

• EPS interfaces and protocols

• E-UTRA frequency bands and UE capabilities

• Current status of the EPS standardisation process

E-UTRAN Protocol Architecture

• Logical, Transport and Physical channels and their relation to the radio interface protocol stack

• X2, S1 and S11-interface protocol stacks

NAS

• Non Access Stratum protocols and procedures (EMM and ESM)

• Idle mode mobility mechanisms

• NAS security mechanisms

S1AP and GTP

• EPS QoS mechanisms: default and dedicated bearers, Traffic Flow Templates and QCI values

• S1 Application Protocol (S1AP) UE Identities

• GTP-C and GTP-U, TEID

• S1AP and GTP procedures

RRC

• Radio Resource Control (RRC) procedures

• UE states and state transitions (NAS and RRC)

• System information

• Radio Bearer concept

PDCP and RLC

• PDCP functionality for Control and User Plane

• Robust Header Compression (RoHC)

• PDCP ARQ functionality at handover

• RLC modes and functionality

• RLC ARQ mechanism

MAC and E-UTRA Scheduling

• Medium Access Control(MAC)functionality in UE and eNodeB

• MAC control procedures

• Scheduling Requests

• Dynamic scheduling and semi-persistent scheduling

• Hybrid-ARQ

E-UTRA Physical Layer

• E-UTRA refresh: modulation, OFDM basics and channel-to-resource mapping

• Channel coding for the DL-SCH, including Turbo coding and HARQ rate matching

• UL and DL physical channels for data and L1/L2 control signalling

• UL and DL physical layer control procedure and HARQ data transfer

The X2 Interface

• X2 Application Protocol (X2AP) procedures

• Inter cell interference cooperation

• Data forwarding and in-order delivery of data PDUs at handover

Interworking

• Interworking with legacy R8 or pre-R8 3GPP networks

• Interworking with non-3GPP access networks

• Overview of various solutions for interworking with the CS domain

E-UTRAN Signalling Procedures

• The random access procedure

• RRC connection establishment

• Attach procedure, including establishment of Default EPS bearer and security associations.

• Dedicated EPS bearer establishment and interaction with Policy and Charging Control (PCC)

• Handover with data forwarding via X2-interface

• Inter-RAT handover with data forwarding via the S12-interface (Direct Tunnel)

Return to list of training courses