Your very own IoT: Let's talk WiFi

by Andrey Katsman - Embedded.com, Sept. 17, 2015 – 

Welcome back! In today's post, we will talk about WiFi -- a few general concepts about it, its relationship to the CC3200, some practical ways to use it, and lastly, a little step-by-step project.

WiFi (a.k.a wireless LAN) is a way to connect multiple clients in a wireless network. It is so common nowadays that we hardly even think about it anymore unless we are away from home and must go into "hunting" mode to find it wherever we can. Even though we take WiFi for granted, the internals of it are quite interesting and complicated. The set of protocols to describe the MAC (or media access control) and physical layers of this communication is specified by the IEEE 802.11 standard, which was first introduced in 1997 and has seen a magnificent amount of improvement since then. The standard covers multiple variations (and some that even account for future applications), but I will focus on the most relevant ones today. In consumer networking products, you will encounter these four common varieties of the IEEE 802.11 standard:

• 801.11b: This operates in the microwave 2.4GHz frequency range and allows throughput of 11 Mbit/s.
• 802.11g: This operates in same range (2.4GHz) and allows a rate of 54 Mbit/s.
• 802.11n: This introduces MIMO (multiple input, multiple output) antenna technology and operates mainly in same 2.4GHz range but adds optional support for the 5GHz frequency range. This version supports data rates up to 600 Mbit/s.
• 802.11ac: This improved version of 802.11n supports wider channels in the 5GHz range and adds a more advanced MIMO variation, allowing the increased maximal throughput of 1.3 Gbit/s.