1. A base station device for communicating with a terminal device, the base station device comprising:radio resource control (RRC) processing circuitry configured to transmit RRC configuration information to the terminal device,
transmission processing circuitry configured to transmit downlink control information (DCI) on a physical downlink control channel (PDCCH) and transmit downlink data on a physical downlink shared channel (PDSCH), and
transmission signal generation circuitry configured to take encoded bits in the downlink data as input and produce modulation symbols, wherein
in a case that the RRC configuration information includes first information for superposition coded modulation and one of a first plurality of DCI formats is used, the DCI includes second information indicating that an interference with the modulation symbols is included and indicating transmission power ratio,
in a case that the RRC configuration information includes the first information and one of a second plurality of DCI formats is used, the DCI does not include the second information,
in a case that the second information indicates a first value, the modulation symbols are produced without including an interference signal, and
in a case that the second information indicates a value other than the first value and the value other than the first value indicates that the transmission power ratio is less than 0.5, the modulation symbols are produced with including the interference signal.