Referring to the radio portion of the link between wireless devices, such as a cellular telephone and a base station. In the context of the OSI Reference Model, the air interface operates at the Physical Layer and the Data Link Layer. See also cellular radio, Data Link Layer, link, OSI Reference Model, Physical Layer, radio, and wireless.
The technology used for the radio transmission between mobile devices and the base station in a cellular network. It is the wireless counterpart of the physical layer 1 in the OSI model (see OSI model). Also called a "radio interface," the air interface defines the frequency, channel bandwidth and modulation scheme. For example, TDMA and CDMA modulation are used in GSM and CDMA cellular networks respectively, while OFDMA is used for LTE. OFDMA was also used for WiMAX. See air card, CDMA, TDMA, OFDMA, LTE and WiMAX.