adaptive frequency hopping (Bluetooth, 802.11) (AFH)

The ISM band in the 2.4 GHz frequency range is used by a wide variety of radio technologies, including 802.11b and Bluetooth. Since the various radio technologies interfere with each other, reduce performance and create interference, a technique called adaptive frequency hopping (AFH) has been developed that can be activated in the event of mutual interference.

AFH technology can be used to change the transmission channel and frequency hopping sequence when an 802.11WLAN using spread-spectrum technology( DSSS) interferes with Bluetooth transmission frequencies. The AFH method then selects the transmission channel with the lowest interference risk. As for the hopping frequency, the hopping frequency can be reduced from 75 frequency hops per second to 15 hops per second.

The AFH method was adopted in the Bluetooth standard in version 1.2 and is used in Bluetooth Low Energy( BLE). AFH can be implemented in a wide variety of ways, each with its own advantages and disadvantages.