This document discusses radio spectrum and wireless networks and protocols. It covers:
- The radio spectrum ranges from 30 Hertz to 300 GHz and is used for technologies like mobile phones, radio, TV and more.
- The spectrum is divided into bands and sub-bands to prevent interference between users.
- Shannon's theorem establishes the maximum possible transmission speed over a channel based on its bandwidth and signal-to-noise ratio.
- Licensed spectrum reserves certain frequencies that individual companies can pay to use exclusively, while unlicensed spectrum allows open use but is more vulnerable to interference.