Differential control information for multi-beam operation
Methods, systems, and devices for wireless communication are described. Generally, the described techniques provide for using different configurations for downlink or uplink transmissions associated with different transmission configuration indication (TCI) states (e.g., transmitted on different beams). In one example, a base station may use different configurations for downlink transmissions to a user equipment (UE), and the base station may indicate the different configurations to the UE. For instance, the base station may transmit downlink control information (DCI) indicating a baseline configuration and other configurations as a delta of the baseline configuration. In another example, a base station may dynamically indicate a timing advance to a UE (e.g., in DCI or flow control feedback) for an uplink transmission from the UE associated with a TCI state, and the UE may use the dynamically indicated timing advance for uplink transmissions associated with the TCI state.
1. A method for wireless communication at a user equipment (UE), comprising:
receiving control signaling indicating a first mapping of indices to configurations for receiving downlink transmissions and a second mapping of indices to differential values between configurations;
receiving, from an access network entity, downlink control information scheduling a first downlink transmission associated with a first transmission configuration indication state and a second downlink transmission associated with a second transmission configuration indication state, the downlink control information comprising an indication of a first configuration for receiving the first downlink transmission and an indication of a differential value between the first configuration and a second configuration for receiving the second downlink transmission; and
receiving the first downlink transmission using the first configuration and the second downlink transmission using the second configuration.
2. The method of claim 1 , further comprising:
receiving an explicit indication of the first configuration in the downlink control information and an explicit indication of the differential value between the first configuration and the second configuration in the downlink control information.
3. The method of claim 1 , further comprising:
identifying an index in the downlink control information used to indicate a configuration for receiving the first downlink transmission;
determining that the index corresponds to the first configuration in the first mapping; and
identifying the first configuration for receiving the first downlink transmission based at least in part on the determining.
4. The method of claim 1 , further comprising:
identifying an index in the downlink control information used to indicate a configuration for receiving the second downlink transmission;
determining that the index corresponds to the differential value between the first configuration and the second configuration in the second mapping;
applying the differential value to the first configuration; and
identifying the second configuration for receiving the second downlink transmission based at least in part on the applying.
5. The method of claim 1 , wherein the control signaling comprises radio resource control signaling.
6. The method of claim 1 , wherein the control signaling comprises medium access control signaling.
7. The method of claim 1 , further comprising:
identifying a codepoint in the downlink control information used to indicate a configuration for receiving the first downlink transmission and a configuration for receiving the second downlink transmission;
identifying a mapping of codepoints to configurations for receiving downlink transmissions, wherein each codepoint maps to a baseline configuration and one or more differential values;
determining that the codepoint corresponds to the first configuration and to the differential value between the first configuration and the second configuration based at least in part on the mapping, wherein the codepoint comprises the indication of the first configuration and the indication of the differential value between the first configuration and the second configuration; and
identifying the first configuration for receiving the first downlink transmission and the second configuration for receiving the second downlink transmission based at least in part on the determining.
8. The method of claim 7 , further comprising:
receiving control signaling indicating the mapping of codepoints to configurations for receiving downlink transmissions.
9. The method of claim 7 , wherein the mapping of codepoints to configurations for receiving downlink transmissions is preconfigured at the UE.
10. The method of claim 1 , wherein the first configuration or the second configuration comprises a modulation and coding scheme, redundancy version, allocation pattern, or a combination thereof.
11. A method for wireless communication at an access network entity, comprising:
transmitting control signaling indicating a first mapping of indices to configurations for receiving downlink transmissions and a second mapping of indices to differential values between configurations;
transmitting, to a user equipment (UE) in downlink control information scheduling a first downlink transmission associated with a first transmission configuration state and a second downlink transmission associated with a second transmission configuration state, an indication of a first configuration for receiving the first downlink transmission and an indication of a differential value between the first configuration and a second configuration for receiving the second downlink transmission; and
transmitting the first downlink transmission using the first configuration and the second downlink transmission using the second configuration.
12. The method of claim 11 , wherein transmitting the indication of the first configuration comprises:
transmitting an explicit indication of the first configuration in the downlink control information, and wherein transmitting the indication of the differential value between the first configuration and the second configuration comprises:
transmitting an explicit indication of the differential value between the first configuration and the second configuration in the downlink control information.
13. The method of claim 11 , wherein transmitting the indication of the first configuration for receiving the first downlink transmission comprises:
transmitting an index in the downlink control information indicating the first configuration for receiving the first downlink transmission, wherein the index corresponds to the first configuration in the first mapping.
14. The method of claim 11 , wherein transmitting the indication of the second configuration for receiving the second downlink transmission comprises:
identifying the differential value between the first configuration and the second configuration; and
transmitting an index in the downlink control information indicating the differential value between the first configuration and the second configuration, wherein the index corresponds to the differential value in the second mapping.
15. The method of claim 11 , wherein the control signaling comprises radio resource control signaling.
16. The method of claim 11 , wherein the control signaling comprises medium access control signaling.
17. The method of claim 11 , further comprising:
identifying a mapping of codepoints to configurations for receiving downlink transmissions, wherein each codepoint maps to a baseline configuration and one or more differential values;
identifying a codepoint in the mapping corresponding to the first configuration and the differential value between the first configuration and the second configuration, wherein transmitting the indication of the first configuration and the indication of the second configuration comprises:
transmitting the codepoint in the downlink control information indicating the first configuration and the differential value between the first configuration and the second configuration.
18. The method of claim 17 , further comprising:
transmitting control signaling indicating the mapping of codepoints to configurations for receiving downlink transmissions.
19. The method of claim 17 , wherein the mapping of codepoints to configurations for receiving downlink transmissions is preconfigured at the access network entity.
20. The method of claim 11 , wherein the first configuration or the second configuration comprises a modulation and coding scheme, redundancy version, allocation pattern, or a combination thereof.
21. An apparatus for wireless communication at a user equipment (UE), comprising:
a processor;
a memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
receive control signaling indicating a first mapping of indices to configurations for receiving downlink transmissions and a second mapping of indices to differential values between configurations;
receive, from an access network entity, downlink control information scheduling a first downlink transmission associated with a first transmission configuration indication state and a second downlink transmission associated with a second transmission configuration indication state, the downlink control information comprising an indication of a first configuration for receiving the first downlink transmission and an indication of a differential value between the first configuration and a second configuration for receiving the second downlink transmission; and
receive the first downlink transmission using the first configuration and the second downlink transmission using the second configuration.
22. The apparatus of claim 21 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive an explicit indication of the first configuration in the downlink control information and an explicit indication of the differential value between the first configuration and the second configuration in the downlink control information.
23. The apparatus of claim 21 , wherein the instructions are executable by the processor to cause the apparatus to:
identify an index in the downlink control information used to indicate a configuration for receiving the first downlink transmission;
determine that the index corresponds to the first configuration in the first mapping; and
identify the first configuration for receiving the first downlink transmission based at least in part on the determining.
24. The apparatus of claim 21 , wherein the instructions are executable by the processor to cause the apparatus to:
identify an index in the downlink control information used to indicate a configuration for receiving the second downlink transmission;
determine that the index corresponds to the differential value between the first configuration and the second configuration in the second mapping;
apply the differential value to the first configuration; and
identify the second configuration for receiving the second downlink transmission based at least in part on the applying.
25. The apparatus of claim 21 , wherein:
the control signaling comprises radio resource control signaling.
26. The apparatus of claim 21 , wherein:
the control signaling comprises medium access control signaling.
27. An apparatus for wireless communication at an access network entity, comprising:
a processor;
a memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
transmit control signaling indicating a first mapping of indices to configurations for receiving downlink transmissions and a second mapping of indices to differential values between configurations;
transmit, to a user equipment (UE) in downlink control information scheduling a first downlink transmission associated with a first transmission configuration state and a second downlink transmission associated with a second transmission configuration state, an indication of a first configuration for receiving the first downlink transmission and an indication of a differential value between the first configuration and a second configuration for receiving the second downlink transmission; and
transmit the first downlink transmission using the first configuration and the second downlink transmission using the second configuration.