Method and apparatus for hybrid automatic repeat request in a wireless communication system

Abstract

A method and apparatus for handling Hybrid Automatic Repeat reQuest (HARQ) retransmission in a User Equipment (UE) includes being configured with at least one Secondary Cell (SCell), sending an UpLink (UL) transmission corresponding to an uplink grant, and setting a HARQ FEEDBACK variable corresponding to the UL transmission to Acknowledgement (ACK) if a HARQ feedback reception corresponding to the UL transmission is prohibited due to RF retuning.

What is claimed is: 
     
         1 . A method for handling Hybrid Automatic Repeat reQuest (HARQ) retransmission in a User Equipment (UE) comprising:
 being configured with at least one Secondary Cell (SCell);   sending an UpLink (UL) transmission corresponding to an uplink grant; and   setting a HARQ FEEDBACK variable corresponding to the UL transmission to Acknowledgement (ACK) if a HARQ feedback reception corresponding to the UL transmission is prohibited due to RF retuning.   
     
     
         2 . The method of  claim 1 , wherein the uplink grant is carried by a physical downlink control channel (PDCCH) received from an eNB. 
     
     
         3 . The method of  claim 1 , wherein the HARQ FEEDBACK variable is initialized with Negative Acknowledgement (NACK). 
     
     
         4 . The method of  claim 1 , wherein the RF retuning occurs at SCell activation/deactivation transitions. 
     
     
         5 . The method of  claim 1 , wherein the RF retuning occurs at measurements on a deactivated SCell. 
     
     
         6 . The method of  claim 1 , wherein a non-adaptive retransmission corresponding to the UL transmission is not generated in the UE if the HARQ FEEDBACK variable corresponding to the UL transmission is set to ACK. 
     
     
         7 . A User Equipment (UE) for use in a wireless communication system, the UE comprising:
 a control circuit;   a processor installed in the control circuit; and   a memory installed in the control circuit and coupled to the processor;   wherein the processor is configured to execute a program code stored in memory to handle a Hybrid Automatic Repeat reQuest (HARQ) retransmission by:
 being configured with at least one Secondary Cell (SCell); 
 sending an UpLink (UL) transmission corresponding to an uplink grant; and 
 setting a HARQ FEEDBACK variable corresponding to the UL transmission to Acknowledgement (ACK) if a HARQ feedback reception corresponding to the UL transmission is prohibited due to RF retuning. 
   
     
     
         8 . The device of  claim 7 , wherein the uplink grant is carried by a physical downlink control channel (PDCCH) received from an eNB. 
     
     
         9 . The device of  claim 7 , wherein the HARQ FEEDBACK variable is initialized with Negative Acknowledgement (NACK). 
     
     
         10 . The device of  claim 7 , wherein the RF retuning occurs at SCell activation/deactivation transitions. 
     
     
         11 . The device of  claim 7 , wherein the RF retuning occurs at measurements on a deactivated SCell. 
     
     
         12 . The device of  claim 7 , wherein a non-adaptive retransmission corresponding to the UL transmission is not generated in the UE if the HARQ FEEDBACK variable corresponding to the UL transmission is set to ACK.