(RRH), performs a radio transceiver function.baseband unit in the radio base station. To minimize attenuation through the antenna cable, Remote Radio Units are attached to the antenna mast, usually directly next to or below the radio antenna. RRU units communicate with the baseband unit via the CPRI interface and with the subscriber
unit via the air interface
. The remote radio unit is controlled by the radio networkcontroller. Both units, the RRU unit and the controller form the radio base station.