Acknowledgment feedback for multiple active downlink semi-persistent scheduling configurations
Methods, systems, and devices for wireless communications are described. A base station may configure uplink resources within a slot to enable a user equipment (UE) to transmit an acknowledgment (ACK) feedback message for multiple downlink semi-persistent scheduling (SPS) configurations. For example, the base station may transmit an additional configuration to the UE that indicates uplink resources that the UE can use to transmit acknowledgment feedbacks for multiple downlink messages received according to the SPS configurations, where the UE determines which uplink resource to use based on a number of acknowledgment information bits to be transmitted for the acknowledgment feedback message. For example, if the number of acknowledgment information bits is below a threshold value, the UE may use a first uplink resource configured by the base station. Alternatively, if the number of acknowledgment information bits is above the threshold value, the UE may use a second uplink resource.
1. A method for wireless communication at a user equipment (UE), comprising:
receiving a first downlink signal according to a first semi-persistent scheduling (SPS) configuration, wherein acknowledgment information for the first downlink signal is scheduled to be transmitted within a set of control channel resources during a first slot;
determining that at least one symbol in the set of control channel resources in the first slot is unavailable for transmitting the acknowledgment information;
determining that a second slot is a next available slot for transmitting the acknowledgment information;
identifying a threshold quantity of slots allowable to defer transmitting the acknowledgment information; and
transmitting the acknowledgment information to a network device using the set of control channel resources in the second slot based at least in part on the second slot being the next available slot and based at least in part on the second slot being located less than or equal to the threshold quantity of slots from the first slot.
2. A method for wireless communication at a network device, comprising:
transmitting, to a user equipment (UE), a first downlink signal according to a first semi-persistent scheduling (SPS) configuration, wherein acknowledgment information for the first downlink signal is scheduled to be transmitted within a set of control channel resources during a first slot;
determining that at least one symbol in the set of control channel resources in the first slot is unavailable for transmission, by the UE, of the acknowledgment information;
determining that a second slot is a next available slot for the transmission, by the UE, of the acknowledgment information;
identifying a threshold quantity of slots allowable to defer transmitting the acknowledgment information; and
receiving the acknowledgment information from the UE using the set of control channel resources in the second slot based at least in part on the second slot being the next available slot and based at least in part on the second slot being located less than or equal to the threshold quantity of slots from the first slot.
3. An apparatus for wireless communication at a user equipment (UE), comprising:
one or more processors,
memory coupled with the one or more processors; and
instructions stored in the memory and executable by the one or more processors to cause the apparatus to:
receive a first downlink signal according to a first semi-persistent scheduling (SPS) configuration, wherein acknowledgment information for the first downlink signal is scheduled to be transmitted within a set of control channel resources during a first slot;
determine that at least one symbol in the set of control channel resources in the first slot is unavailable for transmitting the acknowledgment information;
determine that a second slot is a next available slot for transmitting the acknowledgment information;
identify a threshold quantity of slots allowable to defer transmitting the acknowledgment information; and
transmit the acknowledgment information to a network device using the set of control channel resources in the second slot based at least in part on the second slot being the next available slot and based at least in part on the second slot being located less than or equal to the threshold quantity of slots from the first slot.
4. The method of claim 1 , wherein determining that the at least one symbol in the set of control channel resources in the first slot is unavailable for transmitting the acknowledgment information comprises:
identifying that the at least one symbol in the first slot is unavailable due to a time domain duplexing conflict.
5. The method of claim 4 , wherein the time domain duplexing conflict includes the at least one symbol in the first slot being unavailable for uplink transmissions.
6. The method of claim 4 , wherein the time domain duplexing conflict includes the at least one symbol in the first slot being a downlink symbol.
7. The method of claim 1 , wherein determining that the second slot is the next available slot for transmitting the acknowledgment information comprises:
determining that all symbols within the set of control channel resources in the second slot are available for transmitting the acknowledgment information.
8. The method of claim 1 , further comprising:
multiplexing the acknowledgment information that has been deferred from the first slot to the second slot with additional acknowledgment information that was scheduled to be transmitted during the second slot.
9. The method of claim 1 , further comprising:
determining control channel resources of the set of control channel resources to be used for transmission of the acknowledgment information based at least in part on a total payload of an uplink control channel transmission that includes the acknowledgment information.
10. The method of claim 1 , further comprising:
selecting the set of control channel resources from a plurality of sets of control channel resources available in a first configuration that includes a plurality of SPS configurations, the SPS configuration being one of the plurality of SPS configurations.
11. The method of claim 2 , wherein determining that the at least one symbol in the set of control channel resources in the first slot is unavailable for the transmission of the acknowledgment information comprises:
identifying that the at least one symbol in the first slot is unavailable due to a time domain duplexing conflict.
12. The method of claim 11 , wherein the time domain duplexing conflict includes the at least one symbol in the first slot being unavailable for uplink transmissions.
13. The method of claim 11 , wherein the time domain duplexing conflict includes the at least one symbol in the first slot being a downlink symbol.
14. The method of claim 2 , wherein determining that the second slot is the next available slot for the transmission of the acknowledgment information comprises:
determining that all symbols within the set of control channel resources in the second slot are available for the transmission of the acknowledgment information.
15. The method of claim 2 , wherein receiving the acknowledgment information from the UE using the set of control channel resources in the second slot further comprises:
receiving the acknowledgment information multiplexed with additional acknowledgment information that was scheduled to be transmitted by the UE during the second slot.
16. The method of claim 2 , further comprising:
determining control channel resources of the set of control channel resources to be used for the transmission of the acknowledgment information based at least in part on a total payload of an uplink control channel transmission that includes the acknowledgment information.
17. The method of claim 2 , wherein the set of control channel resources used for the transmission of the acknowledgment information are one of a plurality of sets of control channel resources available to the UE via a first configuration that includes a plurality of SPS configurations, the SPS configuration being one of the plurality of SPS configurations.
18. The apparatus of claim 3 , wherein, to determine that the at least one symbol in the set of control channel resources in the first slot is unavailable for transmitting the acknowledgment information, the instructions are further executable by the one or more processors to cause the apparatus to:
identify that the at least one symbol in the first slot is unavailable due to a time domain duplexing conflict.
19. The apparatus of claim 18 , wherein the time domain duplexing conflict includes the at least one symbol in the first slot being unavailable for uplink transmissions.
20. The apparatus of claim 18 , wherein the time domain duplexing conflict includes the at least one symbol in the first slot being a downlink symbol.
21. The apparatus of claim 3 , wherein, to determine that the second slot is the next available slot for transmitting the acknowledgment information, the instructions are further executable by the one or more processors to cause the apparatus to:
determine that all symbols within the set of control channel resources in the second slot are available for transmitting the acknowledgment information.
22. The apparatus of claim 3 , wherein the instructions are further executable by the one or more processors to cause the apparatus to:
multiplex the acknowledgment information that has been deferred from the first slot to the second slot with additional acknowledgment information that was scheduled to be transmitted during the second slot.
23. An apparatus for wireless communication at a network device, comprising:
one or more processors,
memory coupled with the one or more processors; and
instructions stored in the memory and executable by the one or more processors to cause the apparatus to:
transmit, to a user equipment (UE), a first downlink signal according to a first semi-persistent scheduling (SPS) configuration, wherein acknowledgment information for the first downlink signal is scheduled to be transmitted within a set of control channel resources during a first slot;
determine that at least one symbol in the set of control channel resources in the first slot is unavailable for transmission, by the UE, of the acknowledgment information;
determine that a second slot is a next available slot for the transmission, by the UE, of the acknowledgment information;
identify a threshold quantity of slots allowable to defer transmitting the acknowledgment information; and
receive the acknowledgment information from the UE using the set of control channel resources in the second slot based at least in part on the second slot being the next available slot and based at least in part on the second slot being located less than or equal to the threshold quantity of slots from the first slot.
24. The apparatus of claim 23 , wherein, to determine that the at least one symbol in the set of control channel resources in the first slot is unavailable for the transmission of the acknowledgment information, the instructions are further executable by the one or more processors to cause the apparatus to:
identify that the at least one symbol in the first slot is unavailable due to a time domain duplexing conflict.
25. The apparatus of claim 24 , wherein the time domain duplexing conflict includes the at least one symbol in the first slot being unavailable for uplink transmissions.
26. The apparatus of claim 24 , wherein the time domain duplexing conflict includes the at least one symbol in the first slot being a downlink symbol.
27. The apparatus of claim 23 , wherein, to determine that the second slot is the next available slot for the transmission of the acknowledgment information, the instructions are further executable by the one or more processors to cause the apparatus to:
determine that all symbols within the set of control channel resources in the second slot are available for the transmission of the acknowledgment information.
28. The apparatus of claim 23 , wherein, to receive the acknowledgment information from the UE using the set of control channel resources in the second slot, the instructions are further executable by the one or more processors to cause the apparatus to:
receive the acknowledgment information multiplexed with additional acknowledgment information that was scheduled to be transmitted by the UE during the second slot.