Digital Communication Systems

CHAPTER

1

Introduction

1.1  Historical Background

In order to provide a sense of motivation, this introductory treatment of digital communications begins with a historical background of the subject, brief but succinct as it may be. In this first section of the introductory chapter we present some historical notes that identify the pioneering contributors to digital communications specifically, focusing on three important topics: information theory and coding, the Internet, and wireless communications. In their individual ways, these three topics have impacted digital communications in revolutionary ways.

Information Theory and Coding

In 1948, the theoretical foundations of digital communications were laid down by Claude Shannon in a paper entitled “A mathematical theory of communication.” Shannon’s paper was received with immediate and enthusiastic acclaim. It was perhaps this response that emboldened Shannon to amend the title of his classic paper to “The mathematical theory of communication” when it was reprinted later in a book co-authored with Warren Weaver. It is noteworthy that, prior to the publication of Shannon’s 1948 classic paper, it was believed that increasing the rate of transmission over a channel would increase the probability of error; the communication theory community was taken by surprise when Shannon proved that this was not true, provided the transmission rate was below the channel capacity.

Shannon’s 1948 paper was followed by three ground-breaking advances ...