Voice in LTE/EPS Networks

Voice in LTE/EPS Networks

The Voice in LTE/EPS Networks course describes in a comprehensive – yet easily understandable – way how voice and SMS services are realized in LTE/EPS networks. The course is focused on IMS-based calls/sessions as described in 3GPP specifications and GSMA (GSM Association) documents. However, also the non-IMS CS Fallback scenario is described.

Basic message-level signalling flows are shown to illustrate various traffic cases, procedures and scenarios.

PREREQUISITES:
General knowledge about the architecture, terminology and modes of operation of the GSM/UMTS/EPS radio access and core networks is highly recommended. Basic knowledge of IP networks and protocol stack is recommended. For required background knowledge, we recommend Apis’ LTE/EPC System Overview.

Note: the course is under development and the content is subject to changes.

LTE/EPS System Overview
•    LTE/EPS nodes and architecture
•    Basic procedures: Network Attach, PDN Connection Setup
•    Relation to legacy 3GPP networks and other networks

EPS Bearers
•    Default and Dedicated Bearers
•    QoS for Bearers
•    Bearer Setup procedures

IMS – the IP Multimedia Subsystem
•    Multimedia over IP using SIP
•    IMS nodes and architecture
•    IMS subscriber identities
•    Basic traffic cases; Registration and Invitation
•    IMS vs basic SIP – a comparison

IMS Voice Call/Session setup in LTE/EPS
•    The IMS Profile for Voice and SMS
•     Requirements on UEs and networks
•    Call setup traffic case
•    MMTel (AS, ICSI etc...)
•    PCC - Policy and Charging Control

Subscriber profiles and UE capabilities/settings
•    Subscriber profiles in HSS etc
•    UE capabilities, profiles and settings
•    Storage/handling  of profiles, context etc

Idle Mode Mobility handling
•    Registration procedures
•    Cell and RAT selection procedures
•    Info to UE from the network
•    Area updates and ISR scenarios

Inter RAT handovers
•    PS Handovers between E-UTRAN  and UTRAN
•    Requirements on UTRAN
•    Measurement control

IMS - Interworking with the Circuit Switched Domain
•    SR-VCC: Single Radio Voice Call Continuity
•    The Sv and I2 interfaces
•    ISC – IMS Service Continuity
•    Breakout to CS Domain
•    Incoming call from CS Domain
•    ICS – IMS Centralized Services

Circuit Switched Fallback (CS Fallback)
•    CS Fallback principles
•    Requirements on UE and network
•    The SGs interface
•    Call setup for Mobile Originating and Termination calls

SMS handling in LTE/EPS
•    SMS over SGs
•    SMS over IP with IMS Interworking

Security
•    LTE/EPS Security
•    IMS Security

IMS Emergency calls
•    E-CSCF
•    Emergency call principles

Roaming Scenarios
•    Local breakout vs home routed traffic
•    IMS in visited network
•    No IMS in visited network