Preface

Last two decades have seen two major transformations in the syllabus of Digital Communication at the undergraduate level. Techniques like QAM, MSK, OQPSK, etc. entered the realm of classroom discussions from technical journals. This was the first transformation that happened in the mid- nineties in the Indian universities and engineering institutions. The second transformation came mainly during the last five years with the onset of telecom revolution, particularly the mobile telephone s penetration to commoners. Every serious electronics student started relating the abstract digital communication techniques, hitherto known only in classrooms, to the making of the tiny phone in his or her pocket. This rejuvenated the interest in the so-called ‘stochastic” (i.e. arbitrary!) subject of Digital Communication’. Hence, this was the appropriate time for teachers to bring in the advanced concepts of geometrical representation of signals and underscoring the unity and diversity of various modern modulation techniques.

A new textbook of Digital Communication addressing these emerging pedagogical issues was in order and this book is aimed at being just that. The underpinning in this text is the optimisation between the bandwidth efficiency and power efficiency of a communication system, without losing the goal of its applicability to the ongoing telecom revolution.

The emphasis in this book is on clarifying the concept from the basics, not on the implementation of a functional block. It is my belief that implementation of a particular functional block should be emphasised in circuit courses, particularly the courses on RF design. Also, due to the modern state-of-the-art technology, most of the implementation issues are becoming trivial with the advent of generalised implementation block in hardware as well as firmware and software (software radio!).