Method and apparatus for implementing uplink transmission in flexible frequency division duplex system

A user equipment (UE) in a flexible frequency division duplex (FDD) system, the UE comprising:

• a configuration obtaining unit;
• and
• a sending and detection unit;
• wherein the configuration obtaining unit is configured to receive signaling of a base station eNB, and obtain an uplink carrier configuration of a FDD cell configured to indicate an uplink/downlink sub-frame distribution on an uplink carrier of the FDD cell, the uplink carrier configuration comprising positions of the fixed uplink sub-frames and flexible sub-frames, and
• wherein the sending and detection unit is configured to:
• detect an uplink grant based on the uplink carrier configuration obtained by the configuration obtaining unit,
• send PUSCH data and/or detection of PHICH data,
• for sub-frame n that is located in a position of a flexible sub-frame on the uplink carrier of the FDD cell, if the sending and detection unit detects the uplink grant corresponding to the sub-frame n, determine to not detect a downlink grant corresponding to the sub-frame n on a downlink carrier of the FDD cell, and
• if the sending and detection unit has not detected the uplink grant corresponding to the sub-frame n, determine to detect a downlink grant corresponding to the sub-frame n on the downlink carrier of the FDD cell.