Flew

WiFi is the de facto standard for providing wireless access to the Internet using the 2.4GHz ISM band. Tens of billions of WiFi devices were shipped worldwide and WiFi Access Points (APs) are ubiquitous in public, enterprise and personal environments. We have also witnessed the fast growth of IoT (Internet of Things) devices. With more stringent board-space and power requirements, many IoT devices use more power-efficient, lower-cost and smaller wireless chips, such as Bluetooth or proprietary wireless chips. Due to the mismatch of different wireless technologies, these devices access the Internet indirectly via far less ubiquitous IoT gateways. Bluetooth and most proprietary wireless chips are based on FSK (Frequency-Shift Keying) modulation since FSK can be implemented with extremely simple and low-power FM (Frequency Modulation) circuits.