5G NG-RAN Architecture

The course starts with a general description of the 5G System elements and principles, various RAN — core and dual connectivity options, followed by a discussion of aspects of the new air interface and the nodes, interfaces and procedures in the NG-RAN. Some interworking aspects with E-UTRA radio and non-3GPP access are also discussed.

This course provides a thorough overview of the Next-Generation Radio Access Network (NG-RAN) which is part of the 3GPP 5G System. Both Non-Stand Alone (NSA) and Stand-Alone (SA) operation options are described.

Prerequisites

Knowledge of LTE/4G is required. Basic knowledge of the overall 5G System is recommended. Good 5G background knowledge is provided e.g. by Apis 5G System Overview course.

Course content

Network Overview

• 5G System introduction, new Network Functions and Service Based Architecture
• E-UTRAN and NG-RAN elements: gNB, eNB, ng-eNB, en-gNB
• NR and E-UTRA Dual Connectivity options
• Non-Stand Alone (NSA) and Stand-Alone (SA) deployment options
• Connectivity to non-3GPP access
• PDU Sessions and QoS flows

New Radio (NR) Fundamentals

• ITU-R requirements on 5G system radio performance
• NR frequency bands, cell bandwidth, carrier aggregation, millimetre waves
• OFDM NR numerologies, frame and slot structure
• Differences between NR and E-UTRA

Non Stand-Alone NR with EPC

• Architecture for NSA NR
• E-UTRA – NR Dual Connectivity (EN-DC)
• Radio Bearers and CN Connections
• Handling of control plane and user plane
• The Xn interface

Stand-Alone NR with 5GC

• Architecture for SA NR
• NR – NR Dual Connectivity (NR-DC)
• Radio Bearers and CN Connections
• Handling of control plane and user plane

NG-RAN Protocols

• Overview of NG-RAN interfaces and protocols
• N2/N3/NG interfaces and NGAP protocol functions
• Xn interface and XnAP protocol functions
• RRC, SDAP, PDCP, RLC and MAC

NR Uu Channel Architecture

• Overview of the radio interface protocol stack
• RRC protocol overview and states: Idle, Connected, Inactive
• Layer 2 protocols: SDAP, PDCP, RLC, MAC
• RLC Channels, Logical Channels, Transport Channels and Physical Channels

RRC and RRC States

• RRC Overview
• RRC States
• Behaviour of network and UE in IDLE, CONNECTED and INACTIVE states
• RAN Notification Areas

C-RAN – Centralized RAN

• Reasons for C-RAN
• Architecture options: gNB Central Units and Distributed Unit
• gNB-CU Control Plane and User Plane separation
• F1-C, F1-U interfaces
• F1AP – F1 Application Protocol
• E1 interface
• E1AP – E1 Application Protocol