This page shows what a Wi-Fi system looks like from a hardware and software perspective. On the right side in red is a Wi-Fi (and in this case Bluetooth as well) transceiver device, for example the TI WL1271. The larger light gray box represents a Wi-Fi module, which may include additional RF components like a front end module, filter, clock, and antenna connecter. The transceiver will pair up with a host controller via an SDIO connection for Wi-Fi. The reason a microprocessor is required, is shown on the software portion of the diagram. A number of software components are required in a wireless system and thus require a processor to run them. The software includes an operating system, hardware drivers, stacks, profiles, and applications. The Wi-Fi device itself will also host some software, but typically only the firmware and MAC/PHY software.