Harq-ack information feedback method and apparatus

Abstract

An apparatus and method for feeding back hybrid automatic repeat request-acknowledgement (HARQ-ACK) information are provided. The apparatus and method include user equipment (UE) that first receives a downlink grant (DL-GRANT) which schedules downlink HARQ transmission in a time-frequency bundling window corresponding to an uplink subframe used for feeding back HARQ-ACK, obtains a DL downlink assignment index (DL DAI) in the DL-GRANT, and determines a mapping value of each DL DAI. Then, according to the mapping value of the corresponding DL DAI, the HARQ-ACK bit of each HARQ feedback unit is mapped to a corresponding bit of a feedback bit sequence. According to the method and apparatus provided by the present disclosure, useless HARQ-ACK bits may be effectively removed, and efficiency for feeding back HARQ-ACK may be increased. As such, a downlink peak rate of a UE is ensured.

What is claimed is: 
     
         1 . A method for transmitting hybrid automatic repeat request-acknowledgement (HARQ-ACK) information by a user equipment (UE), the method comprising:
 determining a bundling window corresponding to an uplink subframe, wherein the bundling window is a set formed by subframes whose HARQ-ACK is fed back in the uplink subframe, and the subframes in the bundling window are indexed first in increasing order of serving cell index and then in increasing order of subframe index;   generating HARQ-ACK information for data on a physical downlink shared channel (PDSCH), wherein the HARQ-ACK information is for the bundling window; and   transmitting, to a base station, the HARQ-ACK information in the uplink subframe.   
     
     
         2 . The method of  claim 1 ,
 wherein the subframes in the bundling window are indexed, at a first subframe index, in increasing order of the serving cell index and then the subframes in the bundling window are indexed, at a second subframe index, in increasing order of the serving cell index, and   wherein the first subframe index is ahead of the second subframe index in time.   
     
     
         3 . The method of  claim 1 , further comprising:
 receiving, from the base station, control information on a physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH), wherein the control information is used to schedule a HARQ transmission associated with the bundling window.   
     
     
         4 . The method of  claim 1 , further comprising:
 determining a HARQ feedback unit, wherein the HARQ feedback unit is downlink subframe; and   determining a total length of a feedback bit sequence to be fed back in the uplink subframe.   
     
     
         5 . The method of  claim 3 , further comprising:
 mapping a HARQ-ACK bit of the HARQ feedback unit to a bit of the feedback bit sequence.   
     
     
         6 . A method for receiving hybrid automatic repeat request-acknowledgement (HARQ-ACK) information by a base station, the method comprising:
 transmitting, to a user equipment (UE), data on a physical downlink shared channel (PDSCH); and   receiving, from the UE, HARQ-ACK information for the data in an uplink subframe, wherein the HARQ-ACK information is for a bundling window which is a set formed by subframes whose HARQ-ACK is fed back in the uplink subframe,   wherein the subframes in the bundling window are indexed first in increasing order of serving cell index and then in increasing order of subframe index.   
     
     
         7 . The method of  claim 6 ,
 wherein the subframes in the bundling window are indexed, at a first subframe index, in increasing order of the serving cell index and then the subframes in the bundling window are indexed, at a second subframe index, in increasing order of the serving cell index, and   wherein the first subframe index is ahead of the second subframe index in time.   
     
     
         8 . The method of  claim 6 , further comprising:
 transmitting, to the UE, control information on a physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH), wherein the control information is used to schedule a HARQ transmission associated with the bundling window.   
     
     
         9 . A user equipment (UE) for transmitting hybrid automatic repeat request-acknowledgement (HARQ-ACK) information, the UE comprising:
 a transceiver; and   a controller coupled with the transceiver and configured to control to:
 determine a bundling window corresponding to an uplink subframe, wherein the bundling window is a set formed by subframes whose HARQ-ACK is fed back in the uplink subframe, and the subframes in the bundling window are indexed first in increasing order of serving cell index and then in increasing order of subframe index, 
 generate HARQ-ACK information for data on a physical downlink shared channel (PDSCH), wherein the HARQ-ACK information is for the bundling window, and 
 transmit, to a base station, the HARQ-ACK information in the uplink subframe. 
   
     
     
         10 . The UE of  claim 9 ,
 wherein the subframes in the bundling window are indexed, at a first subframe index, in increasing order of the serving cell index and then the subframes in the bundling window are indexed, at a second subframe index, in increasing order of the serving cell index, and   wherein the first subframe index is ahead of the second subframe index in time.   
     
     
         11 . The UE of  claim 9 , wherein the controller is configured to:
 receive, from the base station, control information on a physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH), wherein the control information is used to schedule a HARQ transmission associated with the bundling window.   
     
     
         12 . The UE of  claim 9 , wherein the controller is configured to:
 determine a HARQ feedback unit, wherein the HARQ feedback unit is downlink subframe, and   determine a total length of a feedback bit sequence to be fed back in the uplink subframe.   
     
     
         13 . The UE of  claim 12 , wherein the controller is configured to:
 map a HARQ-ACK bit of the HARQ feedback unit to a bit of the feedback bit sequence.   
     
     
         14 . A base station for receiving hybrid automatic repeat request-acknowledgement (HARQ-ACK) information, the base station comprising:
 a transceiver; and   a controller coupled with the transceiver and configured to control to:
 transmit, to a user equipment (UE), data on a physical downlink shared channel (PDSCH), and 
 receive, from the UE, HARQ-ACK information for the data in an uplink subframe, wherein the HARQ-ACK information is for a bundling window which is a set formed by subframes whose HARQ-ACK is fed back in the uplink subframe, 
   wherein the subframes in the bundling window are indexed first in increasing order of serving cell index and then in increasing order of subframe index.   
     
     
         15 . The base station of  claim 14 ,
 wherein the subframes in the bundling window are indexed, at a first subframe index, in increasing order of the serving cell index and then the subframes in the bundling window are indexed, at a second subframe index, in increasing order of the serving cell index, and   wherein the first subframe index is ahead of the second subframe index in time.   
     
     
         16 . The base station of  claim 14 , wherein the controller is configured to:
 transmit, to the UE, control information on a physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH), wherein the control information is used to schedule a HARQ transmission associated with the bundling window.