Indication of potential NR UL transmission in NE-DC

1. A method of wireless communication at a first base station using a first Radio Access Technology (RAT), comprising:

configuring, for a User Equipment (UE), a first Time Division Duplex Uplink/Downlink (TDD UL/DL) configuration for a first cell using the first RAT;

configuring, for the UE, a second TDD UL/DL configuration for a second cell using the first RAT; and

sending, based on the UE communicating with a second base station that uses a second RAT, an indication of a combined TDD UL/DL configuration for the first RAT to at least one of the UE and the second base station that uses the second RAT to communicate with the UE, wherein the combined TDD UL/DL configuration indicates:

a symbol as an uplink symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration for the first RAT comprises the symbol configured for uplink transmission, or

the symbol as a flexible symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration for the first RAT comprises the symbol configured as flexible.

2. The method of claim 1 , wherein the first base station sends the indication of the combined TDD UL/DL configuration to both the UE and the second base station that communicates with the using the second RAT.

3. The method of claim 1 , wherein the first base station sends the indication of the combined TDD UL/DL configuration to the UE.

4. The method of claim 1 , wherein the first base station sends the indication of the combined TDD UL/DL configuration to the second base station that communicates with the using the second RAT, the combined TDD UL/DL configuration informing the second base station of each symbol configured as the uplink symbol for at least one of the first TDD UL/DL configuration or the second TDD UL/DL configuration or of each symbol configured as the flexible symbol for at least one of the first TDD UL/DL configuration or the second TDD UL/DL configuration.

5. The method of claim 1 , wherein the combined TDD UL/DL configuration indicates the symbol as the uplink symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration comprises the symbol configured for the uplink transmission.

6. The method of claim 1 , wherein the combined TDD UL/DL configuration indicates the symbol as the flexible symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration comprises the symbol configured as flexible.

7. The method of claim 1 , wherein the combined TDD UL/DL configuration comprises at least one of a subcarrier spacing or symbol size based on the first TDD UL/DL configuration that is different than the second TDD UL/DL configuration.

8. The method of claim 1 , wherein at least one of a subcarrier spacing or symbol size of the first TDD UL/DL configuration is different than the second TDD UL/DL configuration, and wherein the combined TDD UL/DL configuration is based on a reference subcarrier spacing or a reference symbol size.

9. An apparatus for wireless communication at a first base station using a first Radio Access Technology (RAT), comprising:

a memory; and

at least one processor coupled to the memory and configured to:

configure, for a User Equipment (UE), a first Time Division Duplex Uplink/Downlink (TDD UL/DL) configuration for a first cell using the first RAT;

configure, for the UE, a second TDD UL/DL configuration for a second cell using the first RAT; and

send, based on the UE communicating with a second base station that uses a second RAT, an indication of a combined TDD UL/DL configuration for the first RAT to at least one of the UE and the second base station that uses the second RAT to communicate with the UE, wherein the combined TDD UL/DL configuration indicates:

a symbol as an uplink symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration for the first RAT comprises the symbol configured for uplink transmission, or

the symbol as a flexible symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration for the first RAT comprises the symbol configured as flexible.

10. The apparatus of claim 9 , wherein the first base station sends the indication of the combined TDD UL/DL configuration to both the UE and the second base station that communicates with the using the second RAT.

11. The apparatus of claim 9 , wherein the first base station sends the indication of the combined TDD UL/DL configuration to the UE.

12. The apparatus of claim 9 , wherein the first base station sends the indication of the combined TDD UL/DL configuration to the second base station that communicates with the using the second RAT, the combined TDD UL/DL configuration informing the second base station of each symbol configured as the uplink symbol for at least one of the first TDD UL/DL configuration or the second TDD UL/DL configuration or of each symbol configured as the flexible symbol for at least one of the first TDD UL/DL configuration or the second TDD UL/DL configuration.

13. The apparatus of claim 9 , wherein the combined TDD UL/DL configuration indicates the symbol as the uplink symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration comprises the symbol configured for the uplink transmission.

14. The apparatus of claim 9 , wherein the combined TDD UL/DL configuration indicates the symbol as the flexible symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration comprises the symbol configured as flexible.

15. The apparatus of claim 9 , wherein the combined TDD UL/DL configuration comprises at least one of a subcarrier spacing or symbol size based on the first TDD UL/DL configuration that is different than the second TDD UL/DL configuration.

16. The apparatus of claim 9 , wherein at least one of a subcarrier spacing or symbol size of the first TDD UL/DL configuration is different than the second TDD UL/DL configuration, and wherein the combined TDD UL/DL configuration is based on a reference subcarrier spacing or a reference symbol size.

17. A method of wireless communication at a base station using a first Radio Access Technology (RAT), comprising:

receiving, from a second base station that communicates with a User Equipment (UE) using a second RAT, a combined Time Division Duplex Uplink/Downlink (TDD UL/DL) configuration for the UE based on a first TDD UL/DL configuration for a first cell using the second RAT and a second TDD UL/DL configuration for a second cell using the second RAT, wherein the combined TDD UL/DL configuration indicates:

a symbol as an uplink symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration for the second RAT comprises the symbol configured for uplink transmission, or

the symbol as a flexible symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration for the second RAT comprises the symbol configured as flexible; and

scheduling communication with the UE using the first RAT based on the combined TDD UL/DL configuration received from the second base station.

18. The method of claim 17 , wherein the first base station schedules uplink communication from the UE using resources that do not overlap with an overlapping symbol that is indicated as uplink or flexible in the combined TDD UL/DL configuration received from the second base station.

19. The method of claim 17 , wherein the combined TDD UL/DL configuration indicates the symbol as the uplink symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration comprises the symbol configured for the uplink transmission.

20. The method of claim 17 , wherein the combined TDD UL/DL configuration indicates the symbol as the flexible symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration comprises the symbol configured as flexible.

21. The method of claim 17 , wherein the combined TDD UL/DL configuration comprises at least one of a subcarrier spacing or symbol size based on the first TDD UL/DL configuration that is different than the second TDD UL/DL configuration.

22. The method of claim 17 , wherein at least one of a subcarrier spacing or symbol size of the first TDD UL/DL configuration is different than the second TDD UL/DL configuration, and wherein the combined TDD UL/DL configuration is based on a reference subcarrier spacing or a reference symbol size.

23. An apparatus for wireless communication at a first base station using a first Radio Access Technology (RAT), comprising:

a memory; and

at least one processor coupled to the memory and configured to:

receive, from a second base station that communicates with a User Equipment (UE) using a second RAT, a combined Time Division Duplex Uplink/Downlink (TDD UL/DL) configuration for the UE based on a first TDD UL/DL configuration for a first cell using the second RAT and a second TDD UL/DL configuration for a second cell using the second RAT, wherein the combined TDD UL/DL configuration indicates:

a symbol as an uplink symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration for the second RAT comprises the symbol configured for uplink transmission, or

the symbol as a flexible symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration for the second RAT comprises the symbol configured as flexible; and

schedule communication with the UE using the first RAT based on the combined TDD UL/DL configuration received from the second base station.

24. The apparatus of claim 23 , wherein the first base station schedules uplink communication from the UE using resources that do not overlap with a symbol that is indicated as uplink or flexible in the combined TDD UL/DL configuration received from the second base station.

25. The apparatus of claim 23 , wherein the combined TDD UL/DL configuration indicates the symbol as the uplink symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration comprises the symbol configured for the uplink transmission.

26. The apparatus of claim 23 , wherein the combined TDD UL/DL configuration indicates the symbol as the flexible symbol if the first TDD UL/DL configuration or the second TDD UL/DL configuration comprises the symbol configured as flexible.

27. The apparatus of claim 23 , wherein the combined TDD UL/DL configuration comprises at least one of a subcarrier spacing or symbol size based on the first TDD UL/DL configuration that is different than the second TDD UL/DL configuration.

28. The apparatus of claim 23 , wherein at least one of a subcarrier spacing or symbol size of the first TDD UL/DL configuration is different than the second TDD UL/DL configuration, and wherein the combined TDD UL/DL configuration is based on a reference subcarrier spacing or a reference symbol size.