One of the first adopters of the ISM bands that the FCC freed for unlicensed use was the IEEE 802.11 technology. The IEEE 802.11 is a suite of protocols with a rich history and different use cases. 802.11 is the specification defining the Media Access Controller (MAC) and physical layer (PHY) of a networking stack. The definition and specifications are governed by the IEEE LAN/MAN Standards Committee. Wi-Fi is the definition of WLAN based on the IEEE802.11 standards but maintained and governed by the non-profit Wi-Fi Alliance. 

802.11 owes its creation to NCR in 1991 who first developed the wireless protocol as a means of networking cash registers. It wasn't until 1999 when the Wi-Fi Alliance was formed that the technology became ubiquitous and pervasive in the burgeoning PC and notebook market. The original protocol is vastly different than modern 802.11 b/g/n/ac protocols. It only supported a 2 Mbps data rate with forward error correction.

The success of IEEE802.11 can be attributed to the layered stack approach of the OSI model. Simply replacing the MAC and PHY layers with IEEE802.11 layers allowed existing TCP/IP infrastructure to seamless be used. Today, nearly every mobile device, notebook, tablet, embedded system, toy, and video game incorporate an IEEE802.11 radio of some kind. That said, 802.11 has had a storied past, particularly in the security model. The original 802.11 security model was based on the UC Berkeley Wired Equivalent Privacy security mechanism that was later proven to be unreliable and easily compromised. Several notable exploits including the TJ Maxx data breach through 802.11 WEP in 2007 resulted in 45 million stolen credit cards. Today, Wi-Fi Protected Access (WPA) and WPA2 using AES 256-bit pre-shared keys have certainly tightened up security and WEP is rarely used. 

This section will detail some of the differences in the 802.11 protocols and particular information relevant to the IoT architect. We will detail the current IEEE802.11ac design and then examine 802.11ah HaLow and 802.11p V2V, as all three are relevant to the internet of things.