A base station communicating with a user device using multiple antennas in a system where a subframe is composed of multiple slots each composed of multiple basic time units is disclosed. The base station includes a first mapping unit configured to map one or more reference signals used for demodulation of one or more L1/L2 control channels and one or more data channels to be transmitted from one or more of the antennas within a predetermined number of basic time units from the beginning of each subframe; and a second mapping unit configured to map reference signals used for demodulation of data channels to be transmitted from other ones of the antennas to one or more basic time units following the basic time units to which the reference signals used for demodulation of the L1/L2 control channels and the data channels are mapped.