1. Introduction

Mobile phones are the technology success story of the 21st century.

They started life back in the 1980's and have seen an astounding growth - no one predicted how successful they were going to be.

Did you know that in 2015 (latest global survey, enquiring in 2017), mobile phones and their apps accounted for 4% of the entire economy of the world - a contribution of $3 trillion.

This section will explain how the technology works and how it relates to its technology cousin - the satellite phone.