User terminal, radio base station and radio communication method

Abstract

The present invention is designed so that it is possible to feed back HARQ-ACKs adequately even when a plurality of component carriers are configured in a radio communication system. The present invention provides a receiving section that receives DL signals transmitted from a plurality of component carriers (CCs), and a control section that controls transmission of an HARQ-ACK in response to a received DL signal based on a counter DAI included in the downlink control information, and the counter DAI is configured to three or more bits in predetermined downlink control information. Also, the counter DAI can be comprised of varying numbers of bits depending on the number of CCs configured in the user terminal or the number of CCs where listening is applied to DL transmission.

Dependencies are inferred from the claim text.