This book presents the description of 4G mobile and IMS networks. Different procedures are described: attachment and registration, deregistration and detachment, establishment and release of VoLTE and ViLTE sessions in different cases (interconnection, roaming). eSRVCC mechanism, that allows the transfer of the communication from a 4G mobile network to 2G/3G networks, is also given.
Supplements functions are also provided: ROHC, SPS, DRX, TTI Bundling for the radio interface, SMS, ICS, Roaming, Emergency call, conversational services.