TECHNIQUES FOR DERIVING A SOUNDING REFERENCE SIGNAL-BASED MULTI-TRANSMISSION AND RECEPTION POINT DOWNLINK PRECODING
Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) may receive a sounding reference signal (SRS) resource configuration indicating one or more resources over which the UE may transmit one or more SRSs to one or more transmission and reception points (TRPs) within a multi-TRP communications system applying a multi-TRP communication scheme. The SRS resource configuration may configure the one or more resources based on a type of multi-TRP communication scheme being applied by multiple TRPs within the multi-TRP communications system and the UE may support SRS-based channel state information (CSI) acquisition within the multi-TRP communication scheme based on transmitting one or more SRSs over the configured resources. The UE may also receive configurations indicating spatial relations between each configured resource, two or more downlink reference signals, and a demodulation reference signal of an associated downlink transmission.
1 . (canceled)
2 . A user equipment (UE), comprising:
one or more processors; and
one or more memories coupled to the one or more processors and storing instructions executable by the one or more processors to cause the UE to:
receive a sounding reference signal resource configuration indicating a quantity of sounding reference signal resources, wherein the quantity of sounding reference signal resources indicated by the sounding reference signal resource configuration is based at least in part on a type of a first multi-transmission and reception point communication scheme used for downlink communications performed by two or more transmission and reception points;
transmit one or more sounding reference signals over the quantity of sounding reference signal resources according to the sounding reference signal resource configuration; and
receive a downlink transmission from at least one of the two or more transmission and reception points, the downlink transmission based at least in part on the one or more sounding reference signals.
3 . The UE of claim 2 , wherein the instructions are further executable by the one or more processors to cause the UE to:
receive a configuration associating the quantity of sounding reference signal resources with two or more downlink reference signals, each of the two or more downlink reference signals from one of the two or more transmission and reception points.
4 . The UE of claim 3 , wherein, to receive the configuration associating the quantity of sounding reference signal resources with the two or more downlink reference signals, the instructions are further executable by the one or more processors to cause the UE to:
receive an indication of a spatial relation between the quantity of sounding reference signal resources and the two or more downlink reference signals.
5 . The UE of claim 3 , wherein, to receive the configuration associating the quantity of sounding reference signal resources with the two or more downlink reference signals, the instructions are further executable by the one or more processors to cause the UE to:
receive an indication, for the quantity of sounding reference signal resources, of an uplink transmission configuration indicator state associated with the two or more downlink reference signals.
6 . The UE of claim 3 , wherein the two or more downlink reference signals comprise two or more channel state information reference signals, two or more tracking reference signals, or two or more synchronization signal blocks.
7 . The UE of claim 2 , wherein, to receive the sounding reference signal resource configuration indicating the quantity of sounding reference signal resources, the instructions are further executable by the one or more processors to cause the UE to:
receive an indication of one sounding reference signal resource, and wherein, to transmit the one or more sounding reference signals over the quantity of sounding reference signal resource, the instructions are further executable by the one or more processors to cause the UE to:
transmit the one or more sounding reference signals to each of the two or more transmission and reception points over the one sounding reference signal resource, wherein the first multi-transmission and reception point communication scheme comprises a single-frequency network communication scheme or a space-division multiplexing communication scheme.
8 . The UE of claim 2 , wherein, to receive the sounding reference signal resource configuration indicating the quantity of sounding reference signal resources, the instructions are further executable by the one or more processors to cause the UE to:
receive an indication of multiple sounding reference signal resources, and wherein transmitting the one or more sounding reference signals over the quantity of sounding reference signal resources comprises:
transmit a sounding reference signal over each of the multiple sounding reference signal resources to a different one of the two or more transmission and reception points, wherein the first multi-transmission and reception point communication scheme comprises a time-division multiplexing communication scheme or a frequency-division multiplexing communication scheme.
9 . The UE of claim 2 , wherein, to receive the sounding reference signal resource configuration indicating the quantity of sounding reference signal resources, the instructions are further executable by the one or more processors to cause the UE to:
receive a sounding reference signal resource set configuration associated with a sounding reference signal resource set including a plurality of sounding reference signal resources, the plurality of sounding reference signal resources including the quantity of sounding reference signal resources.
10 . The UE of claim 2 , wherein, to receive the sounding reference signal resource configuration indicating the quantity of sounding reference signal resources, the instructions are further executable by the one or more processors to cause the UE to:
receive an indication of an association between each of the quantity of sounding reference signal resources and one or more antenna panels of the UE; and
receive an indication of an antenna panel switching pattern for changing the association between each of the quantity of sounding reference signal resources and the one or more antenna panels of the UE over time.
11 . The UE of claim 2 , wherein the instructions are further executable by the one or more processors to cause the UE to:
receive downlink control information scheduling the downlink transmission, the downlink control information including information associated with a downlink reception beam to be used by the UE; and
select the downlink reception beam based at least in part on the information associated with the downlink reception beam included in the downlink control information, wherein receiving the downlink transmission is based at least in part on receiving the downlink control information and selecting the downlink reception beam.
12 . The UE of claim 2 , wherein, to transmit the one or more sounding reference signals over the quantity of sounding reference signal resources, the instructions are further executable by the one or more processors to cause the UE to:
transmit a first sounding reference signal to a first transmission and reception point of the two or more transmission and reception points using a first transmit beam and a first antenna panel of the UE and a second sounding reference signal to a second transmission and reception point of the two or more transmission and reception points using a second transmit beam and a second antenna panel of the UE simultaneously.
13 . The UE of claim 2 , wherein, to transmit the one or more sounding reference signals over the quantity of sounding reference signal resources, the instructions are further executable by the one or more processors to cause the UE to:
transmit one sounding reference signal to one of the two or more transmission and reception points using a transmit beam and an antenna panel of the UE.
14 . The UE of claim 2 , wherein, to receive the downlink transmission from the at least one of the two or more transmission and reception points, the instructions are further executable by the one or more processors to cause the UE to:
receive the downlink transmission from each of the two or more transmission and reception points according to a second multi-transmission and reception point communication scheme based at least in part on the one or more sounding reference signals.
15 . The UE of claim 2 , wherein, to receive the downlink transmission from the at least one of the two or more transmission and reception points, the instructions are further executable by the one or more processors to cause the UE to:
receive the downlink transmission from one of the two or more transmission and reception points according to a single-transmission and reception point communication scheme based at least in part on the one or more sounding reference signals.
16 . The UE of claim 2 , wherein the downlink transmission is associated with a downlink precoding, a rank, or a modulation and coding scheme that is based at least in part on the one or more sounding reference signals.
17 . A method for wireless communication at a user equipment (UE), comprising:
receiving a sounding reference signal resource configuration indicating a quantity of sounding reference signal resources, wherein the quantity of sounding reference signal resources indicated by the sounding reference signal resource configuration is based at least in part on a type of a first multi-transmission and reception point communication scheme used for downlink communications performed by two or more transmission and reception points;
transmitting one or more sounding reference signals over the quantity of sounding reference signal resources according to the sounding reference signal resource configuration; and
receiving a downlink transmission from at least one of the two or more transmission and reception points, the downlink transmission based at least in part on the one or more sounding reference signals.
18 . The method of claim 17 , further comprising:
receiving a configuration associating the quantity of sounding reference signal resources with two or more downlink reference signals, each of the two or more downlink reference signals from one of the two or more transmission and reception points.
19 . The method of claim 17 , wherein receiving the sounding reference signal resource configuration indicating the quantity of sounding reference signal resources comprises:
receiving an indication of one sounding reference signal resource, and wherein transmitting the one or more sounding reference signals over the quantity of sounding reference signal resources comprises:
transmitting the one or more sounding reference signals to each of the two or more transmission and reception points over the one sounding reference signal resource, wherein the first multi-transmission and reception point communication scheme comprises a single-frequency network communication scheme or a space-division multiplexing communication scheme.
20 . A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by one or more processors to:
receive a sounding reference signal resource configuration indicating a quantity of sounding reference signal resources, wherein the quantity of sounding reference signal resources indicated by the sounding reference signal resource configuration is based at least in part on a type of a first multi-transmission and reception point communication scheme used for downlink communications performed by two or more transmission and reception points;
transmit one or more sounding reference signals over the quantity of sounding reference signal resources according to the sounding reference signal resource configuration; and
receive a downlink transmission from at least one of the two or more transmission and reception points, the downlink transmission based at least in part on the one or more sounding reference signals.
21 . The non-transitory computer-readable medium of claim 20 , wherein the instructions are further executable by the one or more processors to:
receive a configuration associating the quantity of sounding reference signal resources with two or more downlink reference signals, each of the two or more downlink reference signals from one of the two or more transmission and reception points.