ABSTRACT
In many ways, the most important aspect of an Internet Protocol (IP) Multimedia Subsystem (IMS) application is placed in users’ hands. The mobile device, also known as user equipment (UE) in Third Generation Partnership Project (3GPP™) specifications, and the IMS applications it contains are the parts of an IMS-based service that end users will experience. It will be used to judge the overall success of any service offering. A well-designed, robust implementation in the UE is therefore critical to any IMS application deployment. The IMS architecture of the UE and some of the unique issues that come up when realizing an IMS application will be discussed in this chapter.
