1. An integrated circuit comprising:circuitry, which, in operation, controls
receiving downlink data transmitted on a first component carrier and a second component carrier; and
transmitting a response signal, which is indicative of a plurality of error detection results of the downlink data of the first component carrier and the second component carrier, on either one of a first physical uplink control channel (PUCCH) resource indicated by a first PUCCH resource index or a second PUCCH resource indicated by a second PUCCH resource index,
wherein the first PUCCH resource index is determined based on a value of a transmission power control (TPC) command for an uplink control channel and the second PUCCH resource index is determined based on a value obtained by adding 1 to the first PUCCH resource index.