The PDF walks you through the historical evolution of modulation:
: Building complex communications from individual samples, a key focus for SDR practitioners. 3. Wireless Channel Challenges wireless communications from the ground up pdf
This sparked the "Cellular" revolution. Engineers realized they could divide a city into small "cells," each with its own tower. This allowed thousands of people to use the same frequencies simultaneously without crashing the system. The Modern Symphony The PDF walks you through the historical evolution