Terminal device, base station device, communication method, and integrated circuit

A terminal device comprising:

• transmission circuitry configured to transmit a first Rank Indicator (RI) associated with a first CSI-RS resource in a first Channel State Information (CSI) process in a first downlink component carrier of a first bandwidth class of a first band in a first band combination and a second RI associated with a second CSI-RS resource in the first CSI process;
• and
• reception circuitry configured to receive a Physical Downlink Shared CHannel (PDSCH) in the first downlink component carrier, wherein
• each of the first RI and the second RI is an RI for PDSCH transmission in the first downlink component carrier, and corresponds to a quantity of useful layers,
• the transmission circuitry is configured to transmit capability information including first information and second information,
• the reception circuitry is configured to receive third information indicating a first maximum quantity of layers for the first downlink component carrier,
• the first information indicates the first bandwidth class corresponding to a quantity of contiguous downlink component carriers in the first band to be supported by the terminal device,
• the second information indicates second maximum quantities of layers supported by the terminal device, the second maximum quantities corresponding to respective ones of bandwidth classes of the first band, and the bandwidth classes including the first bandwidth class,
• in a case that the third information is configured, a third maximum quantity of layers assumed for determining a bit width for the first RI and a fourth maximum quantity of layers assumed for determining a bit width for the second RI are determined according to the third information,
• in a case that the third information is not configured, the third maximum quantity of layers assumed for determining the bit width for the first RI and the fourth maximum quantity of layers assumed for determining the bit width for the second RI are determined according to a smallest one of a first number and a second number,
• the first number is maximum of the second maximum quantities of the layers, and
• the second number is a largest one of a quantity of antenna ports of the first CSI-RS resource and a quantity of antenna ports of the second CSI-RS resource.

A base station device comprising:

• reception circuitry configured to receive a first Rank Indicator (RI) associated with a first CSI-RS resource in a first Channel State Information (CSI) process in a first downlink component carrier of a first bandwidth class of a first band in a first band combination and a second RI associated with a second CSI-RS resource in the first CSI process;
• and
• transmission circuitry configured to transmit a Physical Downlink Shared CHannel (PDSCH) in the first downlink component carrier, wherein
• each of the first RI and the second RI is an RI for PDSCH transmission in the first downlink component carrier, and corresponds to a quantity of useful layers,
• the reception circuitry is configured to receive capability information including first information and second information,
• the transmission circuitry is configured to transmit third information indicating a first maximum quantity of layers for the first downlink component carrier,
• the first information indicates the first bandwidth class corresponding to a quantity of contiguous downlink component carriers in the first band to be supported by the terminal device,
• the second information indicates second maximum quantities of layers supported by the terminal device, the second maximum quantities corresponding to respective ones of bandwidth classes of the first band, and the bandwidth classes including the first bandwidth class,
• in a case that the third information is configured, a third maximum quantity of layers assumed for determining a bit width for the first RI and a fourth maximum quantity of layers assumed for determining a bit width for the second RI are determined according to the third information,
• in a case that the third information is not configured, the third maximum quantity of layers assumed for determining the bit width for the first RI and the fourth maximum quantity of layers assumed for determining the bit width for the second RI are determined according to a smallest one of a first number and a second number,
• the first number is maximum of the second maximum quantities of the layers, and
• the second number is a largest one of a quantity of antenna ports of the first CSI-RS resource and a quantity of antenna ports of the second CSI-RS resource.

A communication method to be used by a terminal device, the communication method comprising:

• transmitting a first Rank Indicator (RI) associated with a first CSI-RS resource in a first Channel State Information (CSI) process in a first downlink component carrier of a first bandwidth class of a first band in a first band combination and a second RI associated with a second CSI-RS resource in the first CSI process;
• receiving a Physical Downlink Shared CHannel (PDSCH) in the first downlink component carrier, wherein
• each of the first RI and the second RI is an RI for PDSCH transmission in the first downlink component carrier, and corresponds to a quantity of useful layers;
• transmitting capability information including first information and second information;
• and
• receiving third information indicating a first maximum quantity of layers for the first downlink component carrier, wherein
• the first information indicates the first bandwidth class corresponding to a quantity of contiguous downlink component carriers in the first band to be supported by the terminal device,
• the second information indicates second maximum quantities of layers supported by the terminal device, the second maximum quantities corresponding to respective ones of bandwidth classes of the first band, and the bandwidth classes including the first bandwidth class,
• in a case that the third information is configured, a third maximum quantity of layers assumed for determining a bit width for the first RI and a fourth maximum quantity of layers assumed for determining a bit width for the second RI are determined according to the third information,
• in a case that the third information is not configured, the third maximum quantity of layers assumed for determining the bit width for the first RI and the fourth maximum quantity of layers assumed for determining the bit width for the second RI are determined according to a smallest one of a first number and a second number,
• the first number is maximum of the second maximum quantities of the layers, and
• the second number is a largest one of a quantity of antenna ports of the first CSI-RS resource and a quantity of antenna ports of the second CSI-RS resource.

A communication method to be used by a base station device, the communication method comprising:

• receiving a first Rank Indicator (RI) associated with a first CSI-RS resource in a first Channel State Information (CSI) process in a first downlink component carrier of a first bandwidth class of a first band in a first band combination and a second RI associated with a second CSI-RS resource in the first CSI process;
• transmitting a Physical Downlink Shared CHannel (PDSCH) in the first downlink component carrier, wherein
• each of the first RI and the second RI is an RI for PDSCH transmission in the first downlink component carrier, and corresponds to a quantity of useful layers;
• receiving capability information including first information and second information;
• and
• transmitting third information indicating a first maximum quantity of layers for the first downlink component carrier, wherein
• the first information indicates the first bandwidth class corresponding to a quantity of contiguous downlink component carriers in the first band to be supported by the terminal device,
• the second information indicates second maximum quantities of layers supported by the terminal device, the second maximum quantities corresponding to respective ones of bandwidth classes of the first band, and the bandwidth classes including the first bandwidth class,
• in a case that the third information is configured, a third maximum quantity of layers assumed for determining a bit width for the first RI and a fourth maximum quantity of layers assumed for determining a bit width for the second RI are determined according to the third information,
• in a case that the third information is not configured, the third maximum quantity of layers assumed for determining the bit width for the first RI and the fourth maximum quantity of layers assumed for determining the bit width for the second RI are determined according to a smallest one of a first number and a second number,
• the first number is maximum of the second maximum quantities of the layers, and
• the second number is a largest one of a quantity of antenna ports of the first CSI-RS resource and a quantity of antenna ports of the second CSI-RS resource.