Bernard Sklar - Digital Communications: Fundamentals and Applications (Communications Engineering & Emerging Technology Series from Ted Rappaport)

This third edition of Digital Communications: Fundamentals and Applications is an updated version of the original and second edition publications. The following key features have been updated and changed:

• We added a chapter dealing with orthogonal frequency-division multiplexing (OFDM). OFDM utilizes closely spaced orthogonal subcarriers. Data are partitioned into groups, such that each group is assigned a subcarrier, which is then modulated in a conventional way. The technique allows for elegant mitigation of intersymbol interference and intercarrier interference. A cyclic prefix is used to trick the channel into performing circular convolution instead of linear convolution, which helps maintain orthogonality. The primary advantage of OFDM is its ability to cope with severe channel multipath conditions, such as frequency-selective fading, without requiring complex equalization filters.

• We also added a chapter on multiple input, multiple output (MIMO) systems. The uniqueness of MIMO stems from time being complemented with the spatial dimension obtained by using several antennas (at the transmitter and receiver). We focus on spatial multiplexing and space-time coding to examine how MIMO can improve BER or increase capacity or bothwithout expending additional power or bandwidth. It involves exploiting any multipath channel conditions. We examine available trade-offs between capacity and robustness and consider multi-user (MU-MIMO) systems where multiple independent users can simultaneously access MIMO base stations.

• In order to keep the book in single-volume format while adding the new OFDM and MIMO chapters, we chose to provide some of the material online. Therefore, in this third edition, the material on encryption and decryption has become .

This third edition is intended to provide comprehensive coverage of digital communication systems for senior-level undergraduates, first-year graduate students, and practicing engineers. Although the emphasis is on digital communications, necessary analog fundamentals are included because analog waveforms are used for the radio transmission of digital signals. The key feature of a digital communication system is that it deals with a finite set of discrete messages, in contrast to an analog communication system, in which messages are defined on a continuum. The objective at the receiver of a digital system is not to reproduce a waveform with precision; it is instead to determine from a noise-perturbed signal which of the finite set of waveforms had been sent by the transmitter. In fulfillment of this objective, there has arisen an impressive assortment of signal processing techniques.

This book describes these signal processing techniques in the context of a unified structure, a block diagram that appears at the beginning of each chapter. In each chapter, applicable portions of the diagram are emphasized. One of the main purposes of this book is to ensure awareness of the big picture, even while delving into the details. Signals and key processing steps are traced from the information source through the transmitter, channel, receiver, and, ultimately, to the information sink. Signal transformations are organized according to functional classes: formatting and source coding, baseband signaling, bandpass signaling, equalization, channel coding, multiplexing and multiple access, spreading, and synchronization. Throughout the book, emphasis is placed on system goals and the need to trade off basic system parameters such as signal-to-noise ratio, probability of error, and bandwidth expenditure.

deals with turbo codes and low-density parity-check