Techniques for improving URLLC communications in new radio

1. A method of wireless communications, comprising:

identifying at least a first hybrid automatic repeat request (HARQ) transmission and a second HARQ transmission, wherein at least one of the identified HARQ transmissions is for ultra-reliable low-latency communications (URLLC);

receiving an indication including information of reference signal handling for the identified HARQ transmissions, wherein the information indicates at least one of:

a relationship between the first HARQ transmission and the second HARQ transmission;

that the reference signal handling includes an application of same precodings or same phase shifts to the identified HARQ transmissions;

that the reference signal handling includes an application of different precodings or different phase shifts to the identified HARQ transmissions; or

that coherent channel estimation is to be applied for the identified HARQ transmissions; and

performing the reference signal handling based on the information.

2. The method of claim 1 , further comprising:

receiving the first HARQ transmission, wherein the first HARQ transmission is precoded for a first service type and transmitted using a first set of antenna ports from a number of antenna ports, wherein each antenna port of the first set of antenna ports is associated with a respective set of resource elements; and

receiving the second HARQ transmission, wherein the second HARQ transmission is precoded for a second service type and transmitted using a second set of antenna ports from a number of antenna ports, wherein each antenna port of the second set of antenna ports is associated with a respective set of resource elements.

3. The method of claim 2 , wherein the first service type is URLLC and the second service type is URLLC or enhanced Mobile Broadband (eMBB).

4. The method of claim 1 , wherein the information in the indication indicates a number of antenna ports, or a service type, or both, associated with each identified HARQ transmission.

5. The method of claim 1 , wherein the indication is received in radio resource control (RRC) configuration, in a physical channel or signal, or dynamically in a resource grant.

6. The method of claim 1 , further comprising:

for each of the identified HARQ transmissions for URLLC, mapping a transport block (TB) for URLLC to a respective set of resources, wherein the mapping the TB comprises:

mapping the first HARQ transmission of the TB to a first set of resource elements, and the second HARQ transmission of the TB to a second set of resource elements; or

mapping the first HARQ transmission to a first set of sub-bands across a first set of component carrier (CCs), and the second HARQ transmission to a second set of sub-bands across a second set of CCs.

7. The method of claim 1 , further comprising receiving the identified HARQ transmissions in a same TB or different TBs.

8. The method of claim 1 , further comprising:

receiving a first downlink transmission of a TB from a first transmission point (TP);

receiving the first HARQ transmission of the TB from a second TP, wherein the first HARQ transmission is the first retransmission of the TB; and

receiving the second HARQ transmission of the TB from at least one of the first TP or the second TP, wherein the second HARQ transmission is the second retransmission of the TB.

9. The method of claim 1 , wherein the indication is a first indication, the method further comprising:

receiving a second indication including information for handling uplink HARQ transmissions;

identifying at least two uplink HARQ transmissions of a TB;

selecting a respective set of precodings or phase shifts for each identified uplink HARQ transmission based on the information in the second indication; and

transmitting each of the at least two uplink HARQ transmissions based on the respective set of precodings or phase shifts.

10. The method of claim 9 , wherein the first indication and the second indication are part of a same indication.

11. The method of claim 9 , wherein the information in the second indication indicates that a same or different set of precodings or phase shifts for each identified uplink HARQ transmission is to be applied.

12. The method of claim 9 , wherein the second indication is received in an uplink grant.

13. The method of claim 9 , further comprising:

transmitting a first uplink transmission of a TB to a first transmission point (TP);

transmitting the first uplink HARQ transmission of the at least two uplink HARQ transmissions to a second TP, wherein the first uplink HARQ transmission is the first retransmission of the TB; and

transmitting the second uplink HARQ transmission of the at least two uplink HARQ transmissions to the first TP and the second TP, wherein the second uplink HARQ transmission is the second retransmission of the TB.

14. An apparatus for wireless communications, comprising:

a receiver;

a memory configured to store instructions; and

at least one processor communicatively coupled to the receiver and the memory, wherein the at least one processor is configured to execute the instructions to:

identify at least a first hybrid automatic repeat request (HARQ) transmission and a second HARQ transmission, wherein at least one of the identified HARQ transmissions is for ultra-reliable low-latency communications (URLLC);

receive, via the receiver, an indication including information of reference signal handling for the identified HARQ transmissions, wherein the information indicates at least one of:

a relationship between the first HARQ transmission and the second HARQ transmission;

that the reference signal handling includes an application of same precodings or same phase shifts to the identified HARQ transmissions;

that the reference signal handling includes an application of different precodings or different phase shifts to the identified HARQ transmissions; or

that coherent channel estimation is to be applied for the identified HARQ transmissions; and

perform the reference signal handling based on the information.

15. The apparatus of claim 14 , wherein the at least one processor is configured to execute further instructions to:

receive, via the receiver, the first HARQ transmission, wherein the first HARQ transmission is precoded for a first service type and transmitted using a first set of antenna ports from a number of antenna ports, wherein each antenna port of the first set of antenna ports is associated with a respective set of resource elements; and

receive, via the receiver, the second HARQ transmission, wherein the second HARQ transmission is precoded for a second service type and transmitted using a second set of antenna ports from a number of antenna ports, wherein each antenna port of the second set of antenna ports is associated with a respective set of resource elements.

16. The apparatus of claim 15 , wherein the first service type is URLLC and the second service type is URLLC or enhanced Mobile Broadband (eMBB).

17. The apparatus of claim 14 , wherein the information in the indication indicates a number of antenna ports, or a service type, or both, associated with each identified HARQ transmission.

18. The apparatus of claim 14 , wherein the indication is received in radio resource control (RRC) configuration, in a physical channel or signal, or dynamically in a resource grant.

19. The apparatus of claim 14 , for each of the identified HARQ transmissions for URLLC, wherein the at least one processor is configured to execute instructions to map a transport block (TB) for URLLC to a respective set of resources, wherein the instructions to map the TB comprises further instructions executed by the at least one processor to:

map the first HARQ transmission of the TB to a first set of resource elements, and the second HARQ transmission of the TB to a second set of resource elements; or

map the first HARQ transmission to a first set of sub-bands across a first set of component carrier (CCs), and the second HARQ transmission to a second set of sub-bands across a second set of CCs.

20. The apparatus of claim 14 , wherein the at least one processor is configured to execute further instructions to receive, via the receiver, the identified HARQ transmissions in a same TB or different TBs.

21. The apparatus of claim 14 , wherein the at least one processor is configured to execute further instructions to:

receive, via the receiver, a first downlink transmission of a TB from a first transmission point (TP);

receive, via the receiver, the first HARQ transmission of the TB from a second TP, wherein the first HARQ transmission is the first retransmission of the TB; and

receive, via the receiver, the second HARQ transmission of the TB from at least one of the first TP or the second TP, wherein the second HARQ transmission is the second retransmission of the TB.

22. The apparatus of claim 14 , wherein the indication is a first indication, and the apparatus further comprising:

a transmitter, wherein the at least one processor is communicatively coupled to the transmitter and configured to execute the instructions to:

receive, via the receiver, a second indication including information for handling uplink HARQ transmissions;

identify at least two uplink HARQ transmissions of a TB;

select a respective set of precodings or phase shifts for each identified uplink HARQ transmission based on the information in the second indication; and

transmit, via the transmitter, each of the at least two uplink HARQ transmissions based on the respective set of precodings or phase shifts.

23. The apparatus of claim 22 , wherein the first indication and the second indication are part of a same indication.

24. The apparatus of claim 22 , wherein the information in the second indication indicates that a same or different set of precodings or phase shifts for each identified uplink HARQ transmission is to be applied.

25. The apparatus of claim 22 , wherein the second indication is received in an uplink grant.

26. The apparatus of claim 22 , wherein the at least one processor is configured to execute further instructions to:

transmit, via the transmitter, a first uplink transmission of a TB to a first transmission point (TP);

transmit, via the transmitter, the first uplink HARQ transmission of the at least two uplink HARQ transmissions to a second TP, wherein the first uplink HARQ transmission is the first retransmission of the TB; and

transmit, via the transmitter, the second uplink HARQ transmission of the at least two uplink HARQ transmissions to the first TP and the second TP, wherein the second uplink HARQ transmission is the second retransmission of the TB.

27. An apparatus for wireless communications, comprising:

means for identifying at least a first hybrid automatic repeat request (HARQ) transmission and a second HARQ transmission, wherein at least one of the identified HARQ transmissions is for ultra-reliable low-latency communications (URLLC);

means for receiving an indication including information of reference signal handling for the identified HARQ transmissions, wherein the information indicates at least one of:

a relationship between the first HARQ transmission and the second HARQ transmission;

that the reference signal handling includes an application of same precodings or same phase shifts to the identified HARQ transmissions;

that the reference signal handling includes an application of different precodings or different phase shifts to the identified HARQ transmissions; or

that coherent channel estimation is to be applied for the identified HARQ transmissions; and

means for performing the reference signal handling based on the information.

28. A non-transitory computer-readable medium storing computer executable code, comprising:

code for identifying at least a first hybrid automatic repeat request (HARQ) transmission and a second HARQ transmission, wherein at least one of the identified HARQ transmissions is for ultra-reliable low-latency communications (URLLC);

code for receiving an indication including information of reference signal handling for the identified HARQ transmissions, wherein the information indicates at least one of:

a relationship between the first HARQ transmission and the second HARQ transmission;

that the reference signal handling includes an application of same precodings or same phase shifts to the identified HARQ transmissions;

that the reference signal handling includes an application of different precodings or different phase shifts to the identified HARQ transmissions; or

that coherent channel estimation is to be applied for the identified HARQ transmissions; and

code for performing the reference signal handling based on the information.