Energy Fundamentals of Radio

Chapter 1A First Look at a Radio Link

1.1 Introduction

This book is about the magic of radio communications and how we can use our shared resources to serve more people with vital communications infrastructure. For resources, we are specifically interested in spectrum, always a finite resource in communications networks but a special challenge with radio waves that are not easily contained in space. We are also interested in energy, because Nature requires it to move bits through a network, and we are an increasingly energy-constrained world.

When it comes to spectral efficiency, the literature is vast. In the decades since the publication of Shannon’s famous capacity limit in 1949, and likely before, many of the brightest minds in communications have devoted themselves to hitting the absolute maximum number of bits per second in a given slice of spectrum. That single-minded pursuit has driven almost every major trend in radio communications since the author turned to the subject in the late 1990s.

In contrast, the literature on energy efficiency, while also large, has lacked the white-hot intensity of pursuit that has been poured into spectral efficiency. The very clear priority has been maximizing data capacity. System architects, consistent with this objective, set the performance requirements for all the hardware in the signal chains of a communications system accordingly. The hardware efficiency literature very dutifully accepts these specifications as set in stone, ...