In the present invention, a demodulation reference signal is transmitted using a plurality of settings in which demodulation reference signals occupy different positions in at least a density or time-frequency resource region of the demodulation reference signals. A base station can transmit, to the user device, information indicating a setting related to a downlink signal or a setting related to an uplink signal from among the plurality of settings, and the user device can receive the demodulation reference signal with the downlink signal or transmit the demodulation reference signal With the uplink signal according to the indicated setting.