Network Coding and Wireless Physical-layer ... - Jacobs University

Chapter 1
Motivation and Overview
This thesis consists of a series of topics which are divided into three parts. We decide to
do so with the aim that each part will be self-contained, i.e., the reader may choose to
read or skip one part without any serious damage. For example, those who have sound
knowledge in communication systems and networks as well as network coding may skip
Part I, those who are interested solely in network coding may read only Part II, and those
who only wish to know the relationship between network coding and WPSG may read
only the last part.
This first part is the introductory part consisting of three chapters. Chapter 2 discusses
the basic knowledge of digital communication systems and networks. Chapter 3 discusses
some aspects of graph theory related to network coding, as well as network coding itself,
which is the major focus of this thesis.
At the beginning of the millennium, Ahlswede et al. [55] made a breakthrough in
information theory by inventing network coding, which significantly increased network
throughput by means of coding. The idea related information theory to graph theory,
providing a means to reach the graph-theoretic max-flow limit in data networks. It stated
that when many sources transmitted different data to many sinks, or when one source
transmitted the same data to many sinks (multicast), the maximum amount of data flow
(max-flow) could not be achieved by means of routing alone. Network coding was needed
to achieve the max-flow.
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