This invention relates to a transmitter apparatus, a receiver apparatus, a transmission method and a notification method that, when a switching between MIMO communication and non-MIMO communication is performed, can suppress the increase of an SRS (Sounding Reference Signal) resource, while suppressing the degradation of trackability of temporal variation of a channel. In a terminal (200), a mapping unit (212) maps an SRS sequence, which is received from a pilot, generating unit (216), on the basis of information related to an SRS hopping pattern, received from a base station (100). For this SRS hopping pattern, the frequency of the SRS transmissions via a first one of a plurality of antennas of the terminal (200) is higher than that of the SRS transmissions via a second one of the plurality of antennas of the terminal (200).