A terminal device, comprising: a transmission unit configured to transmit, to a base station device, a Rank Indicator, RI, determined by the terminal device, the RI corresponding to a number of useful layers and corresponding to Physical Downlink Shared CHannel, PDSCH, transmission in a first downlink component carrier corresponding to a first bandwidth class of a first band in a first band combination; and a reception unit configured to receive a PDSCH from the base station device, wherein the transmission unit is configured to transmit, to the base station device, capability information, the capability information including first information, second information and third information, or the capability information including the first information and the second information, the reception unit is configured to receive, from the base station device, fifth information for the first downlink component carrier corresponding to the first bandwidth class of the first band in the first band combination, the first information indicates a User Equipment, UE, category corresponding to a first maximum number of the layers supported by the terminal device in a downlink, the second information indicates the first bandwidth class of the first band in the first band combination and corresponding to a number of downlink component carriers supported by the terminal device, the third information indicates a second maximum number of the layers supported by the terminal device in the downlink, the second maximum number of the layers being for all of one or more downlink component carriers corresponding to the first bandwidth class of the first band in the first combination, the fifth information indicates a fourth maximum number of the layers configured for the terminal device, in a case that the fifth information for the first downlink component carrier corresponding to the first bandwidth class of the first band in the first band combination is not received, a fifth maximum number of the layers assumed for determining a bit width for the RI is given by referring to any one of the first information and the third information, and in a case that the fifth information for the first downlink component carrier corresponding to the first bandwidth class of the first band in the first band combination is received, the fifth maximum number of the layers assumed for determining the bit width for the RI is given by referring to the fifth information. a transmission unit configured to transmit, to a base station device, a Rank Indicator, RI, determined by the terminal device, the RI corresponding to a number of useful layers and corresponding to Physical Downlink Shared CHannel, PDSCH, transmission in a first downlink component carrier corresponding to a first bandwidth class of a first band in a first band combination; and a reception unit configured to receive a PDSCH from the base station device, wherein the transmission unit is configured to transmit, to the base station device, capability information, the capability information including first information, second information and third information, or the capability information including the first information and the second information, the reception unit is configured to receive, from the base station device, fifth information for the first downlink component carrier corresponding to the first bandwidth class of the first band in the first band combination, the first information indicates a User Equipment, UE, category corresponding to a first maximum number of the layers supported by the terminal device in a downlink, the second information indicates the first bandwidth class of the first band in the first band combination and corresponding to a number of downlink component carriers supported by the terminal device, the third information indicates a second maximum number of the layers supported by the terminal device in the downlink, the second maximum number of the layers being for all of one or more downlink component carriers corresponding to the first bandwidth class of the first band in the first combination, the fifth information indicates a fourth maximum number of the layers configured for the terminal device, in a case that the fifth information for the first downlink component carrier corresponding to the first bandwidth class of the first band in the first band combination is not received, a fifth maximum number of the layers assumed for determining a bit width for the RI is given by referring to any one of the first information and the third information, and in a case that the fifth information for the first downlink component carrier corresponding to the first bandwidth class of the first band in the first band combination is received, the fifth maximum number of the layers assumed for determining the bit width for the RI is given by referring to the fifth information.