Acknowledgements

List of Abbreviations

1 Background

2 VoLTE Deployment Strategies

2.1 Common Networks Everywhere

2.2 GSM/WCDMA View

2.3 CDMA View

3 VoLTE System Architecture

3.1 Overview

3.2 LTE Radio

3.2.1 LTE Radio Background

3.2.2 LTE Radio Architecture

3.3 Evolved Packet Core

3.3.1 What is the Evolved Packet Core?

3.3.2 EPC Entities and Functionalities

3.3.3 EPS Mobility Management

3.3.4 EPS Session Management and QoS

3.4 Control

3.4.1 What is an IP Multimedia Subsystem?

3.4.2 IMS Development History

3.4.3 IMS Fundamentals

3.4.4 IMS Entities

3.4.5 Home Subscriber Server

3.4.6 Policy and Charging Rule Function

3.5 Summary

4 VoLTE Functionality

4.1 Overview

4.2 Radio Functionalities

4.2.1 Bearers and Scheduling

4.2.2 Mobility

4.2.3 Circuit Switched Fallback Handover

4.2.4 Mobility from 2G/3G Back to LTE

4.2.5 Power Saving Features

4.2.6 Positioning Solutions

4.2.7 UE Radio Access Capabilities for VoLTE

4.3 EPC Functionalities

4.3.1 LTE subscriber identification

4.3.2 PDN Connectivity Establishment for the VoLTE User

4.3.3 EPS Dedicated Bearer Setup

4.4 IMS Identification

4.4.1 IP Multimedia Services Identity Module

4.4.2 Public User Identity

4.4.3 Private User Identity

4.4.4 Relationship between Private and Public User Identities

4.4.5 Identification of User’s Device

4.4.6 Identification of Network Entities

4.4.7 Identification of Services (Public Service Identities)

4.4.8 Identification Without ISIM

4.5 IMS Service Provisioning

4.5.1 Enforcement of Allowed Services

4.5.2 Service-Triggering Information

4.5.3 Selection of AS

4.5.4 AS Behaviour

4.5.5 Service Provisioning in Action

4.6 IMS Multimedia Telephony

4.6.1 Introduction

4.6.2 Multimedia Communication

4.6.3 Supplementary Services

5 VoLTE End to End and Signalling

5.1 Overview

5.2 VoLTE Subscription and Device Configuration

5.3 EPS Attach for CSFB/IMS VoIP and Default Bearer Activation

5.4 IMS Registration

5.4.1 Constructing the REGISTER Request

5.4.2 From the UE to the P-CSCF

5.4.3 From the P-CSCF to the I-CSCF

5.4.4 From the I-CSCF to the S-CSCF

5.4.5 S-CSCF Challenges the UE

5.4.6 UE’s Response to the Challenge

5.4.7 Registration at the S-CSCF

5.4.8 The 200 (OK) Response

5.4.9 Third-Party Registration to Application Servers

5.4.10 Subscription to Registration Event Package

5.4.11 Re-Registration and Re-Authentication

5.4.12 De-Registration

5.4.13 Related Standards

5.5 IMS VoIP Session

5.5.1 Constructing the INVITE Request

5.5.2 Routing

5.5.3 Media Negotiation

5.5.4 Media Resource Reservation and Policy Control

5.5.5 Charging

5.5.6 Session Release

5.5.7 Related Standards

5.6 Voice Continuity

5.6.1 PS-PS Intersystem Handover

5.6.2 Single Radio Voice Call Continuity

5.6.3 Summary

5.7 IMS Emergency Session

5.7.1 PDN Connection Setup for Emergency Session

5.7.2 Emergency Registration

5.7.3 Emergency Session

5.8 CS Fallback for Evolved Packet System Call Case(s)

5.8.1 Architecture of CS Fallback for EPS

5.8.2 Description of SGs Interface

5.8.3 Idle Mode Signalling Reduction and Use of CS Fallback for EPS

5.8.4 Idle Mode versus Active Mode UE with CS Fallback for EPS

5.8.5 CS Fallback Attachment

5.8.6 Mobile Originating Call Using CSFB

5.8.7 Mobile Terminating Call Using CSFB

5.8.8 Call Unrelated CSFB Procedures

5.8.9 Mobile Terminating Roaming Retry and Forwarding

5.8.10 Summary

5.9 VoLTE Messaging

5.9.1 Native IMS Messaging

5.9.2 SMS Interworking

5.9.3 Multimedia Messaging Service

5.9.4 Unstructured Supplementary Services Data Simulation in IMS

5.9.5 Summary

6 IMS Centralized Services

7 VoLTE Radio Performance

7.1 Coverage

7.2 Capacity

7.3 Latency

7.4 Summary

8 HSPA Voice over IP

References

Index