A terminal device using carrier aggregation, whereby multiple component carriers are configured for the terminal device, the terminal device comprising: means for receiving downlink control information sent by an access network device, and receiving a data channel scheduled by using the downlink control information, DCI; means for determining an uplink subframe used for sending feedback information corresponding to the received data channel, wherein a first downlink subframe set associated with the uplink subframe comprises a first subset and a second subset, wherein the first subset corresponds to an n-resource-element channel format determined by the number of downlink subframes in the first subset and the second subset corresponds to an m-resource-element channel format determined by the number of downlink subframes in the second subset, m>n; means for determining a channel resource; and means for sending the feedback information on the channel resource in the uplink subframe by using one channel format, wherein: when scheduled downlink subframes constitute the first subset, the channel format is the n-resource-element channel format, and the channel resource is a first uplink channel resource corresponding to the first subset; when scheduled downlink subframes constitute the second subset, the channel format is the m-resource-element channel format, and the channel resource is a second uplink channel resource corresponding to the second subset, wherein a channel resource of the m-resource-element channel format includes a channel resource of the n-resource-element channel format on a same component carrier of the carrier aggregation. means for receiving downlink control information sent by an access network device, and receiving a data channel scheduled by using the downlink control information, DCI; means for determining an uplink subframe used for sending feedback information corresponding to the received data channel, wherein a first downlink subframe set associated with the uplink subframe comprises a first subset and a second subset, wherein the first subset corresponds to an n-resource-element channel format determined by the number of downlink subframes in the first subset and the second subset corresponds to an m-resource-element channel format determined by the number of downlink subframes in the second subset, m>n; means for determining a channel resource; and means for sending the feedback information on the channel resource in the uplink subframe by using one channel format, wherein: when scheduled downlink subframes constitute the first subset, the channel format is the n-resource-element channel format, and the channel resource is a first uplink channel resource corresponding to the first subset; when scheduled downlink subframes constitute the second subset, the channel format is the m-resource-element channel format, and the channel resource is a second uplink channel resource corresponding to the second subset, wherein a channel resource of the m-resource-element channel format includes a channel resource of the n-resource-element channel format on a same component carrier of the carrier aggregation. when scheduled downlink subframes constitute the first subset, the channel format is the n-resource-element channel format, and the channel resource is a first uplink channel resource corresponding to the first subset; when scheduled downlink subframes constitute the second subset, the channel format is the m-resource-element channel format, and the channel resource is a second uplink channel resource corresponding to the second subset, wherein a channel resource of the m-resource-element channel format includes a channel resource of the n-resource-element channel format on a same component carrier of the carrier aggregation. <EOS>