Today’s User Equipment (UE) developers must deal with increased complexity on a variety of fronts. For most UE developers, the IMS subsystem is literally new to its very core, creating the added challenge of learning those details of IMS that are most relevant.
The majority of discussions of IMS protocols currently available are general overviews, containing a small minority of content of interest to the UE developer. This reference guide provides an intuitive introduction to IMS procedures and protocols, focusing on those concepts most relevant to the UE designer. To illustrate the concepts being discussed, several sample call flows (including VoLTE) are broken down and described in more detail.