Method and apparatus for reporting a channel quality in a wireless communication system

Abstract

The present invention provided a method and apparatus for reporting a channel quality in a wireless communication system. A terminal receives an uplink grant from a base station via one of a plurality of downlink component carriers (CCs). The uplink grant includes a channel quality indicator (CQI) request for instructing uplink allocation and CQI reporting. The terminal reports the CQI of the downlink CC being linked to the base station. The downlink CC being linked is one of the plurality of downlink CCs, which is linked to the uplink CC for which the uplink allocation is scheduled.A method and an apparatus for reporting channel quality are discussed. The method according to an embodiment includes receiving, by a terminal configured with a plurality of downlink component carriers (CCs), control information from a base station, the control information including an uplink allocation and a CQI request, the control information including a carrier indicator field (CIF) indicating an uplink CC in which the uplink allocation is scheduled; and transmitting, by the terminal to the base station, the CQI through an uplink CC. The CQI request indicates one of: a triggering of CQI reporting for one downlink CC linked to the uplink CC, indicated by the CIF, among the plurality of downlink CCs; and a triggering of CQI reporting for a first group of downlink CCs among the plurality of downlink CCs.

The invention claimed is: 
     
       1. A method for reporting channel quality by a device in a wireless communication system, the method comprising:
 receiving, by the device, an uplink grant on control information via a physical downlink control channel (PDCCH) through one of a plurality of downlink component carriers (CCs), the uplink grant the control information including an uplink allocation and, a channel quality indicator (CQI) request indicating a triggering of CQI reporting and a carrier indicator (CI) indicating an uplink CC in which the uplink allocation is scheduled, 
 wherein, when a value of related to the CQI request is set to a first value, the CQI request indicates the triggering of CQI reporting is a CQI reporting is triggered for the one downlink CC of the plurality of downlink CCs linked to the uplink CC, which is linked to the uplink CC indicated by the CI, 
 wherein when the value of related to the CQI request is set to a second value, the CQI request indicates the triggering of CQI reporting is the CQI reporting is triggered for a first set of downlink CCs of the plurality of downlink CCs, and 
 wherein when the value ofrelated to the CQI request is set to a third value, the CQI request indicates the triggering of CQI reporting isthe CQI reporting is triggered for a second set of downlink CCs of the plurality of downlink CCs; and 
 reporting, by the device, a CQI for a downlink CC indicated by the CQI request through an via a physical uplink shared channel (PUSCH) of the uplink CC based on the CQI request and the uplink allocation of the PDCCH. 
 
     
     
       2. The method of  claim 1 , wherein the uplink grant further includes a carrier indicator field (CIF) indicating the uplink CC in which the uplink allocation is scheduled. 
     
     
       3. The method of  claim 1 , wherein a number of bits for the CQI request is two. 
     
     
       4. The method of  claim 1 , further comprising:
 receiving information on the first set of downlink CCs and the second set of downlink CCs. 
 
     
     
       5. The method of  claim 1 ,
 wherein a linkage between the one of the plurality of downlink CCs linked to downlink CC and the uplink CC is received via system information. 
 
     
     
       6. The method of  claim 1 , wherein the first value is “1,” the second value is “2,” and the third value is “3.” 
     
     
       7. An apparatus configured for reporting channel quality in a wireless communication system, the apparatus comprising:
 a radio frequency (RF) unit configured to transmit and receive a radio signal; and 
 a processor coupled to the RF unit and configured to:
 receive an uplink grant on control information via a physical downlink control channel (PDCCH) through one of a plurality of downlink component carriers (CCs), the uplink grant control information including an uplink allocation and, a channel quality indicator (CQI) request indicating a triggering of CQI reporting; and a carrier indicator (CI) indicating an uplink CC in which the uplink allocation is scheduled,  
 
 wherein, when a value of related to the CQI request is set to a first value, the CQI request indicates the triggering of CQI reporting is a CQI reporting is triggered for the one downlink CC of the plurality of downlink CCs linked to the uplink CC, which is linked to the uplink CC indicated by the CI, 
 wherein when the value of related to the CQI request is set to a second value, the CQI request indicates the triggering of CQI reporting is reporting is triggered for a first set of downlink CCs of the plurality of downlink CCs, and 
 wherein when the value ofrelated to the CQI request is set to a third value, the CQI request indicates the triggering of CQI reporting isreporting is triggered for a second set of downlink CCs of the plurality of downlink CCs;, and
 report a CQI for a downlink CC indicated by the CQI request through an via a physical uplink shared channel (PUSCH) of the uplink CC based on the CQI request and the uplink allocation of the PDCCH.   
 
     
     
       8. The apparatus of  claim 7 , wherein the uplink grant further includes a carrier indicator field (CIF) indicating the uplink CC in which the uplink allocation is scheduled. 
     
     
       9. The apparatus of  claim 7 , wherein a number of bits for the CQI request is two. 
     
     
       10. The apparatus of  claim 7 , wherein the processor is configured to receive information on the first set of downlink CCs and the second set of downlink CCs. 
     
     
       11. The apparatus of  claim 7 , wherein a linkage between the one of the plurality of downlink CCs linked to the uplink CC is received via system information. 
     
     
       12. The apparatus of  claim 7 , wherein the first value is “1,” the second value is “2,” and the third value is “3.” 
     
     
       13. The method of claim 1, wherein the CQI reporting based on the CQI request corresponds to an aperiodic CQI.  
     
     
       14. The method of claim 1, wherein when the value related to the CQI request is set to the first value, the one downlink CC is identified by a linkage with the uplink CC indicated by the CI.