Functional Overview of Wi‐Fi
Keunwoo Lim · 2024
This chapter introduces the basic functions of Wi-Fi's physical layer and the medium access control layer. It mostly concerns the fundamental functions and architecture of the legacy Wi-Fi or IEEE802.11 legacy version. The physical layer of Wi-Fi defines the methods of representing raw bits through the accessible wireless frequency. This includes frequency modulation, channel allocation usage and digital-analog modulation. Distributed coordination function is the mandatory feature for medium access using Wi-Fi devices. It adopts the carrier sense multiple access with collision avoidance (CSMA-CA) strategy, where CSMA represents the “Listen before send” strategy while the CA mechanism is used to alleviate the hidden terminal problem. The CA can be optionally turned on/off depending on the situation of the network.