In December 2005 the 3rd Generation Partnership Project (3GPP) standardization body for Universal Mobile Telecommunication Standard (UMTS) decided to make a new technology the core of an evolving universal terrestrial radio access network: Orthogonal Frequency Division Multiplexing (OFDM). This book explores the success of this new technology and provides a comprehensive treatment of physical layer topics such as basic transmission principles, channel impairment analysis, channel estimation and synchronization, use of multiple antennas, and peak power reduction techniques. Particular emphasis is placed on the multi-user capacity region and development of “close-to-capacity” transmission schemes in the context of general coding problems, involving trade off analysis with respect to different performance criteria useful in practice. These physical layer driven aspects are accompanied by medium access layer topics such as user scheduling, rate and power control, sub-channel assignment and access techniques, focusing on multi-user techniques, including development of new delay and utility optimization schemes. The interaction and optimization “across layers” and “across systems” are also discussed in-depth.