Base station, terminal, system and methods for transmitting data in time division duplex (TDD) system

The invention provides a base station, a terminal, a system and methods for transmitting data in a time division duplex (TDD) system. One of the methods comprises the following steps that: the base station transmits an uplink scheduling authorization signaling to the terminal on a carrier m and transmits an acknowledgement / negative acknowledgement (ACK/NACK) feedback signaling corresponding to a physical uplink shared channel (PUSCH) to the terminal on the carrier m after receiving uplink data transmitted by the terminal using the PUSCH on a carrier n, wherein the m is not equal to the n; and timing relationship, which is transmitted by the base station, between the sub-frame of uplink scheduling authorization signaling and/or the ACK/NACK feedback signaling and the sub-frame in which the PUSCH is positioned is equal to the time relationship of a hybrid automatic repeat request (HARQ) corresponding to any uplink and downlink allocation in the carrier m or the carrier n. By the technical scheme provided by the invention, cross carrier modulation can be realized by utilizing the conventional time relationship of the HARQ, enhanced inter-cell interference coordination (EICIC) can be realized and lower equipment complexity can be kept simultaneously.