Definition: 802.11h

Extensions to the physical layer of 802.11 for regulatory compliance in Europe in the 5 GHz band (802.11a). To coexist with signals from licensed carriers, 802.11h adds Transmit Power Control (TPC) and Dynamic Frequency Selection (DFS). These functions enable 802.11 devices to "listen" before transmitting so that they can adjust their power and change channels as required.