This book paves the path toward fourth generation (4G) mobile communica-
tion by introducing mobility in heterogeneous IP networks with both third
generation (3G) and wireless local area networks (WLANs), which is seen as
one of the central issues in the becoming 4G of telecommunications networks
and systems. This book presents a thorough overview of 3G networks and
standards and discusses interworking and handover mechanisms between
WLANs and the Universal Mobile Telecommunication System (UMTS).