A user equipment (UE) receives, from a base station apparatus (gNB), a radio resource control message including information used for configuring whether a first reference signal is used for uplink transmissions or a second reference signal is used for uplink transmissions. The first reference signal is a demodulation reference signal associated with a physical uplink shared channel. The second reference signal is a demodulation reference signal associated with a physical uplink shared channel. The UE also transmits, based on the information, to the gNB, the first reference signal on an antenna port. The UE transmits, based on the information, to the gNB, the second reference signal on the same antenna port as the antenna port on which the first reference signal is transmitted. The second reference signal is mapped to resource elements in a resource block, which are different from resource elements in a resource block to which the first reference signal is mapped.