Method of performing HARQ in wireless communication system

1. A method of performing hybrid automatic repeat request (HARQ) in a wireless communication system, carried in a mobile station (MS), the method comprising:

receiving a system configuration signal,

wherein the system configuration signal comprises frame configuration information and HARQ delay information,

wherein the frame configuration information comprises a ratio of a plurality of downlink (DL) subframes to at least one uplink (UL) subframe in a frame,

wherein the frame comprises only 8 subframes and at least one subframe in the frame is an UL subframe,

wherein each subframe in the frame comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols,

wherein a number of the OFDM symbols of at least one subframe in the frame is different from a number of the OFDM symbols of the other subframes in the frame,

wherein the plurality of DL subframes and the at least one UL subframe are allocated at different times in the frame,

wherein the HARQ delay information comprises an association between the at least one UL subframe and at least one DL subframe in the plurality of DL subframes for HARQ,

wherein the HARQ delay information further comprises a delay value indicating the association between the at least one UL subframe and the at least one DL subframe,

wherein the delay value is represented by an absolute time unit, and

wherein every UL subframe in the frame is associated with the at least one DL subframe;

receiving a DL signal in the at least one DL subframe; and

transmitting an acknowledgement (ACK)/not-acknowledgement (NACK) signal for the DL signal in a corresponding UL subframe that is associated with the at least one DL subframe in which the DL signal is received.

2. The method of claim 1 , wherein the system configuration signal is received as a part of system information.

3. The method of claim 2 , wherein the system information is received through a superframe header.

4. The method of claim 1 , wherein the system configuration signal further comprises UL-MAP information, the UL-MAP information comprising information about an UL subframe associated with an UL-MAP included in one of the plurality of DL subframes.

5. An apparatus for wireless communication, the apparatus comprising:

a radio frequency (RF) unit for receiving and transmitting a radio signal; and

a processor coupled with the RF unit or:

receiving a system configuration signal,

wherein the system configuration signal comprises frame configuration information and hybrid automatic repeat request (HARQ) delay information,

wherein the frame configuration information comprises a ratio of a plurality of downlink (DL) subframes to at least one uplink (UL) subframe in a frame,

wherein the frame comprises only 8 subframes and at least one subframe in the frame is an UL subframe,

wherein each subframe in the frame comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols,

wherein a number of the OFDM symbols of at least one subframe in the frame is different from a number of the OFDM symbols of the other subframes in the frame,

wherein the plurality of DL subframes and the at least one UL subframe are allocated at different times in the frame,

wherein the HARQ delay information comprises an association between the at least one UL subframe and at least one DL subframe in the plurality of DL subframes for HARQ,

wherein the HARQ delay information further comprises a delay value indicating the association between the at least one UL subframe and the at least one DL subframe,

wherein the delay value is represented by an absolute time unit, and

wherein every UL subframe in the frame is associated with the at least one DL subframe;

receiving a DL signal in the at least one DL subframe; and

transmitting an acknowledgement (ACK)/not-acknowledgment (NACK) signal for the DL signal in a corresponding UL subframe that is associated with the at least one DL subframe in which the DL signal is received.