Pucch carrying harq-a for multi-trp with non-ideal backhaul

Abstract

Methods, systems, and devices for wireless communications that support physical uplink control channel (PUCCH) carrying hybrid automatic repeat request (HARQ-A) for multiple transmission reception point (multi-TRP) environments with non-ideal backhaul links are described. A user equipment (UE) may support multiple communication links with TRPs and receive distinct physical downlink control channel (PDCCH) messages that include downlink control information (DCI). The DCI may include a timing or resource indication index values for physical uplink control channel (PUCCH) transmission. Based on the index values, the UE may differentiate the received DCI indications. The UE may then schedule PUCCH transmissions, including hybrid automatic repeat request (HARQ) payloads, directed to the TRPs. In some examples, the scheduling may include mapping the PUCCH transmissions to resources or resource groups in configured PUCCH resource set. The UE may then transmit the PUCCH messages via one or more determined beams based on the indication index values.

What is claimed is: 
     
         1 . An apparatus for wireless communication at a user equipment (UE), comprising:
 a processor,   memory coupled to the processor; and   instructions stored in the memory and executable by the processor to cause the apparatus to:
 receive a first downlink control message from a first transmission reception point and a second downlink control message from a second transmission reception point; 
 identify a first resource indication value included in the first downlink control message and a second resource indication value included in the second downlink control message; 
 determine a first resource group based at least in part on the first resource indication value and a second resource group based at least in part on the second resource indication value; and 
 transmit a first uplink control message based at least in part on the first resource group and a second uplink control message based at least in part on the second resource group. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the first uplink control message comprises a first hybrid automatic repeat request payload and the second uplink control message comprises a second hybrid automatic repeat request payload. 
     
     
         3 . The apparatus of  claim 1 , wherein the instructions are operable to cause the apparatus to:
 determine the first resource group based at least in part on a bit included in the first resource indication value; and   determine the second resource group based at least in part on a bit included in the second resource indication value.   
     
     
         4 . The apparatus of  claim 1 , wherein the instructions are operable to cause the apparatus to:
 determine a first set of time and frequency resources in the first resource group based at least in part on one or more additional bits included in the first resource indication value; and   determine a second set of time and frequency resources in the second resource group based at least in part on one or more additional bits included in the second resource indication value.   
     
     
         5 . The apparatus of  claim 4 , wherein the first set of time and frequency resources comprises resources in a first slot of the first uplink control message and the second set of time and frequency resources comprises resources in a second slot of the second uplink control message. 
     
     
         6 . The apparatus of  claim 4 , wherein the first set of time and frequency resources comprises resources in a first set of orthogonal frequency division multiplexed symbols in a slot of the first uplink control message and the second set of time and frequency resources comprises resources in a second set of orthogonal frequency division multiplexed symbols in the slot of the second uplink control message. 
     
     
         7 . The apparatus of  claim 1 , wherein the first resource indication value comprises a first physical uplink control channel resource indication index value and the second resource indication value comprises a second physical uplink control channel resource indication index value. 
     
     
         8 . A method for wireless communication at a user equipment (UE), comprising:
 receiving a first downlink control message from a first transmission reception point and a second downlink control message from a second transmission reception point;   identifying a first resource indication value included in the first downlink control message and a second resource indication value included in the second downlink control message;   determining a first resource group based at least in part on the first resource indication value and a second resource group based at least in part on the second resource indication value; and   transmitting a first uplink control message based at least in part on the first resource group and a second uplink control message based at least in part on the second resource group.   
     
     
         9 . The method of  claim 8 , wherein the first uplink control message comprises a first hybrid automatic repeat request payload and the second uplink control message comprises a second hybrid automatic repeat request payload. 
     
     
         10 . The method of  claim 8 , further comprising:
 determining the first resource group based at least in part on a bit included in the first resource indication value; and   determining the second resource group based at least in part on a bit included in the second resource indication value.   
     
     
         11 . The method of  claim 8 , further comprising:
 determining a first set of time and frequency resources in the first resource group based at least in part on one or more additional bits included in the first resource indication value; and   determining a second set of time and frequency resources in the second resource group based at least in part on one or more additional bits included in the second resource indication value.   
     
     
         12 . The method of  claim 11 , wherein the first set of time and frequency resources comprises resources in a first slot of the first uplink control message and the second set of time and frequency resources comprises resources in a second slot of the second uplink control message. 
     
     
         13 . The method of  claim 11 , wherein the first set of time and frequency resources comprises resources in a first set of orthogonal frequency division multiplexed symbols in a slot of the first uplink control message and the second set of time and frequency resources comprises resources in a second set of orthogonal frequency division multiplexed symbols in the slot of the second uplink control message. 
     
     
         14 . The method of  claim 8 , wherein the first resource indication value comprises a first physical uplink control channel resource indication index value and the second resource indication value comprises a second physical uplink control channel resource indication index value. 
     
     
         15 . An apparatus for wireless communication at a user equipment (UE), comprising:
 means for receiving a first downlink control message from a first transmission reception point and a second downlink control message from a second transmission reception point;   means for identifying a first resource indication value included in the first downlink control message and a second resource indication value included in the second downlink control message;   means for determining a first resource group based at least in part on the first resource indication value and a second resource group based at least in part on the second resource indication value; and   means for transmitting a first uplink control message based at least in part on the first resource group and a second uplink control message based at least in part on the second resource group.   
     
     
         16 . The apparatus of  claim 15 , wherein the first uplink control message comprises a first hybrid automatic repeat request payload and the second uplink control message comprises a second hybrid automatic repeat request payload. 
     
     
         17 . The apparatus of  claim 15 , further comprising:
 means for determining the first resource group based at least in part on a bit included in the first resource indication value; and   means for determining the second resource group based at least in part on a bit included in the second resource indication value.   
     
     
         18 . The apparatus of  claim 17 , further comprising:
 means for determining a first set of time and frequency resources in the first resource group based at least in part on one or more additional bits included in the first resource indication value; and   means for determining a second set of time and frequency resources in the second resource group based at least in part on one or more additional bits included in the second resource indication value.   
     
     
         19 . The apparatus of  claim 15 , wherein the first resource indication value comprises a first physical uplink control channel resource indication index value and the second resource indication value comprises a second physical uplink control channel resource indication index value. 
     
     
         20 . A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code comprising instructions executable by a processor to:
 receive a first downlink control message from a first transmission reception point and a second downlink control message from a second transmission reception point;   identify a first resource indication value included in the first downlink control message and a second resource indication value included in the second downlink control message;   determine a first resource group based at least in part on the first resource indication value and a second resource group based at least in part on the second resource indication value; and   transmit a first uplink control message based at least in part on the first resource group and a second uplink control message based at least in part on the second resource group.