An IEEE Wi-Fi standard providing low-power, long-range wireless transmission for smart home and IoT (Internet of Things) devices. Employing cognitive radio techniques, 802.11af reaches distances of a few hundred meters indoors and one or more kilometers outdoors. Similar to 802.11ah The 802.11af and 802.11ah standards both penetrate walls like over-the-air TV signals. However, 11af operates in the TV white spaces from 54 to 790 MHz, whereas 11ah transmits in the unlicensed frequency band at 900 MHz. See 802.11ah, 802.22, TV white spaces and cognitive radio.