Group communication technologies enable users to form different types of mobile groups and to interact in real time with the participants of these groups. This book provides an in-depth overview of Multimedia Group Communications in the mobile domain. It specifies multimedia group communication concepts, introduces a range of applications, and proposes an evolution path. The concepts cover the «walkie-talkie» voice over IP service, XML list management, and Presence awareness technologies. The applications section embraces session control for closed professional groups and for open consumer groups. The evolution path includes exciting developments such as ‘infotainment’ and communication with non-human group members. Key Features: Easy to understand explanation of the Push to Talk over Cellular (PoC) service, as specified by the Open Mobile Alliance (OMA) Provides technical description of XML Document Management and SIMPLE Presence services Gives examples on how to deploy group communication services over 3GPP IP Multimedia Subsystem (IMS) and between IMS domains Describes innovative use cases for multimedia group communication through integration with value-added services and through the next generation of OMA enablers Multimedia Group Communications is the first exploration to the field of one-to-many connectivity paradigm. It provides essential information on group communication for engineers, programmers and business managers working in the mobile arena, and will also be useful to business development planners and technically aware users.