Wi-Fi is a technology that allows many electronic devices to exchange data or connect to the internet wirelessly using radio waves. The Wi-Fi Alliance defines Wi-Fi devices as any "Wireless Local Area Network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards".
The key advantage of IEEE 802.11 devices is that they allow less-expensive deployment of Local Area Networks (LANs). For places where running cables to every device is not practical, such as outdoor areas and airports, they can host wireless LANs. Products from every brand name can interoperate at a basic level of service thanks to their products being designated as "Wi-Fi Certified" by the Wi-Fi Alliance.
Today, millions of IEEE 802.11 devices are in use around the world and they operate in the same frequency bands, this makes the need for their coexistence critical. Even though over time older devices will be retired, some consumers and businesses will still be using the old standards for years. For some businesses the original 802.11b devices meet their needs and the need to change has not occurred. Wider bandwidth 802.11 deployments must therefore be able to "play nicely" with the older standards, both by limiting their impact on nearby legacy WLANs and by enabling communication with legacy stations.
This primer provides a general overview for each of the 802.11 standards, their PHY layer characteristics and their testing requirements. In this document, we use 802.11 and IEEE 802.11 interchangeably.
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