July 2014
Beginner to intermediate
486 pages
15h 25m
English
book
An Introduction to LTE: LTE, LTE-Advanced, SAE, VoLTE and 4G Mobile Communications, 2nd Edition
by Christopher Cox
Content preview from An Introduction to LTE: LTE, LTE-Advanced, SAE, VoLTE and 4G Mobile Communications, 2nd Edition
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Chapter 22VoLTE and the IP Multimedia Subsystem
In this chapter, we discuss the likely long-term solution for LTE voice calls, namely the delivery of voice over IP streams that are controlled by the IP multimedia subsystem (IMS). The IMS is not part of LTE: instead it is a separate network whose relationship with LTE is the same as that of the Internet. Despite this, it is valuable to cover the IMS as part of this book, because LTE voice calls are important and because the IMS illustrates several aspects of LTE's operation. The delivery of voice calls over LTE and the IMS is often known as Voice over LTE (VoLTE).
In the course of the chapter, we review the history of the IMS and VoLTE, and discuss the architecture and protocols of the IMS and the procedures for registration and call setup. We then cover three aspects of interoperation between the IMS and the 2G/3G circuit switched domain, namely access domain selection, single radio voice call continuity and IMS centralized services, and conclude by discussing IMS emergency calls and SMS. There are some excellent accounts of the IP multimedia subsystem for those who need further detail, notably References [1–3].
22.1 Introduction
22.1.1 The IP Multimedia Subsystem
The IP multimedia subsystem (IMS) was originally designed for the management and delivery of real-time multimedia services over the 3G packet switched domain. It was first defined in 3GPP Release 5, which was frozen in 2002. The specifications attracted a great deal ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.