ABSTRACT
Since the introduction of the basic WiFi technology in 1997, there have been many amendments and advancements to date to address the requirements of new applications and demands. These amendments can be categorized into two groups, mainstream and niche. Mainstream WiFi versions are those that are used by the mass population to access the Internet, while the others target some niche applications to further extend WiFi's utility beyond just Internet access. This chapter systematically examines the evolution in mainstream WiFi covering all the successive amendments including 802.11b, 802.11a, 802.11g, 802.11n (WiFi 4), 802.11ac (WiFi 5), 802.11ax (WiFi 6), and the upcoming 802.11be (WiFi 7). Data rate is the key feature that was consistently pushed to higher and higher limits through these new generations. This chapter explains how factors such as modulation, coding, guard interval, channel width and MIMO streams influence the achievable data rates in WiFi, which helps appreciate the various data rates offered by different WiFi versions. [158 words]
