10 determines the feedback timing corresponding to the primary carrier as the dedicated feedback timing or when the feedback timing corresponding to the primary carrier corresponds to the tdd uplink downlink configuration 0 or 1 or 2 or 6 see table 1 the prescribed dedicated feedback timing is the feedback timing corresponding to the tdd uplink downlink configuration 2 and when the feedback timing corresponding to the primary carrier corresponds to the tdd uplink downlink configuration 3 or 4 see table 1 the prescribed dedicated feedback timing is the feedback timing corresponding to the tdd uplink downlink configuration 4 it shall be noted that in either of the approaches both the network side apparatus 20 and the user equipment 10 need to use the same dedicated feedback timing which can be particularly prescribed through the protocol or notified of by the network side in an implementation the number of bits of the feedback information can be further determined by the user equipment 10 before sending the feedback information and by the network side apparatus 20 before receiving the feedback information preferably for transmission of ack nack information corresponding to the downlink data the size of an ack nack codebook will be determined according to.