Patent ID: 8254295

Claim:
A method of performing hybrid automatic repeat request (HARQ) by a user equipment in a time-division-duplex (TDD) mobile communication system, the method comprising: receiving configuration information of a radio frame from a base station, the configuration information indicating which subframe in the radio frame is reserved for uplink or downlink; receiving data over a plurality of downlink sub frames from the base station; detecting an error from the received data; and transmitting an acknowledgement/non-acknowledgement (ACK/NACK) signal corresponding to the detection of an error from the data received over an uplink subframe to the base station, the uplink subframe being configured by the configuration information, wherein the radio frame is configured by the table as follows: Downlink- Uplink- to-Uplink downlink Switch-point Subframe number configuration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U D S U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D D D 6 5 ms D S U U U D S U U D wherein ‘D’ denotes a downlink subframe, ‘U’ denotes a uplink subframe, and ‘S’ denotes a special subframe.