Techniques for per-polarization beam scheduling for multiple-input multiple-output (MIMO) communication
Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) may transmit or receive a reference signal to or from a base station using a beam pair including a first beam associated with a first polarization and a second beam associated with a second polarization. The UE may select the first beam from a first set of beams associated with the first polarization and may independently select the second beam from a second set of beams associated with the second polarization. In some examples, the UE may select the first beam and the second beam based on the first beam and the second beam each having a greatest beam strength (at the UE or the base station) relative to a remainder of the first set of beams and the second set of beams, respectively.
1. An apparatus for wireless communication at a user equipment (UE), comprising:
one or more memories that store instructions; and
one or more processors coupled with the one or more memories and configured to execute the instructions to cause the UE to:
receive a downlink reference signal from a network device;
select, from a beamforming codebook and based at least in part on historical information stored at the UE that indicates one or more performance statistics associated with beams in the beamforming codebook, a first receive beam and a second receive beam to be measured for receive beam strength with respect to the downlink reference signal, the first receive beam selected from a first set of beams associated with a first polarization in the beamforming codebook and the second receive beam selected from a second set of beams associated with a second polarization in the beamforming codebook in accordance with the one or more performance statistics associated with the beams in the beamforming codebook;
measure, based at least in part on selection of the first receive beam and the second receive beam, a receive strength of the downlink reference signal on both the first receive beam and the second receive beam; and
transmit, to the network device, a beam report that identifies the first receive beam and the second receive beam.
2. The apparatus of claim 1 , wherein, to select the first receive beam and the second receive beam, the one or more processors are configured to execute the instructions to cause the UE to:
select the first receive beam independent of the second receive beam.
3. The apparatus of claim 1 , wherein, to select the first receive beam and the second receive beam, the one or more processors are configured to execute the instructions to cause the UE to:
select the first receive beam from the first set of beams and the second receive beam from the second set of beams based at least in part on the first receive beam and the second receive beam each having a greatest receive beam strength with respect to the downlink reference signal relative to a remainder of the first set of beams and the second set of beams, respectively, in accordance with the one or more performance statistics associated with the beams in the beamforming codebook.
4. The apparatus of claim 3 , wherein the historical information stored at the UE indicates, via the one or more performance statistics associated with the beams in the beamforming codebook, that the first receive beam and the second receive beam each have had the greatest receive beam strength with respect to the downlink reference signal relative to the remainder of the first set of beams and the second set of beams, respectively.
5. The apparatus of claim 3 , wherein the one or more performance statistics include a first receive beam strength associated with the first receive beam with respect to the downlink reference signal, a second receive beam strength associated with the second receive beam with respect to the downlink reference signal, one or more first receive beam strengths associated with the remainder of the first set of beams with respect to the downlink reference signal, and one or more second receive beam strengths associated with the remainder of the second set of beams with respect to the downlink reference signal, wherein the first receive beam strength is the greatest receive beam strength relative to the one or more first receive beam strengths, and wherein the second receive beam strength is the greatest receive beam strength relative to the one or more second receive beam strengths.
6. The apparatus of claim 1 , wherein the one or more processors are configured to execute the instructions to cause the UE to:
communicate with the network device via at least one non-line-of-sight communication path via one or both of the first receive beam and the second receive beam.
7. The apparatus of claim 1 , wherein to transmit the beam report, the one or more processors are configured to execute the instructions to cause the UE to:
include, in the beam report, an indication of a first reference signal receive power value associated with use of the first receive beam and the second receive beam, wherein the first reference signal receive power value is greater than a second reference signal receive power value associated with use of a pre-configured receive beam pair.
8. The apparatus of claim 1 , wherein the first polarization comprises a horizontal polarization and the second polarization comprises a vertical polarization.
9. The apparatus of claim 1 , wherein the downlink reference signal comprises a synchronization signal block that has a beam index which corresponds to a transmission time interval.
10. The apparatus of claim 1 , wherein:
the beamforming codebook is for multiple-input multiple-output communication; and
the UE and the network device communicate over a millimeter wave radio frequency spectrum band.
11. An apparatus for wireless communication at a user equipment (UE), comprising:
one or more memories that store instructions; and
one or more processors coupled with the one or more memories and configured to execute the instructions to cause the UE to:
select, from a beamforming codebook and based at least in part on historical information stored at the UE that indicates one or more performance statistics associated with beams in the beamforming codebook, a first transmit beam and a second transmit beam for transmission of an uplink reference signal, the first transmit beam selected from a first set of beams associated with a first polarization in the beamforming codebook and the second transmit beam selected from a second set of beams associated with a second polarization in the beamforming codebook in accordance with the one or more performance statistics associated with the beams in the beamforming codebook;
transmit, based at least in part on selection of the first transmit beam and the second transmit beam, the uplink reference signal to a network device via both the first transmit beam and the second transmit beam; and
receive, from the network device, a beam report based at least in part on the transmission of the uplink reference signal via the first transmit beam and the second transmit beam.
12. The apparatus of claim 11 , wherein, to select the first transmit beam and the second transmit beam, the one or more processors are configured to execute the instructions to cause the UE to:
select the first transmit beam independent of the second transmit beam.
13. The apparatus of claim 11 , wherein, to select the first transmit beam and the second transmit beam, the one or more processors are configured to execute the instructions to cause the UE to:
select the first transmit beam from the first set of beams and the second transmit beam from the second set of beams based at least in part on the first transmit beam and the second transmit beam each having a greatest receive beam strength at the network device with respect to the uplink reference signal relative to a remainder of the first set of beams and the second set of beams, respectively, in accordance with the one or more performance statistics associated with the beams in the beamforming codebook.
14. The apparatus of claim 13 , wherein the historical information stored at the UE indicates, via the one or more performance statistics associated with the beams in the beamforming codebook, that the first transmit beam and the second transmit beam each have the greatest receive beam strength at the network device with respect to the uplink reference signal relative to the remainder of the first set of beams and the second set of beams, respectively.
15. The apparatus of claim 13 , wherein the one or more performance statistics include a first receive beam strength at the network device associated with the first transmit beam with respect to the uplink reference signal, a second receive beam strength at the network device associated with the second transmit beam with respect to the uplink reference signal, one or more first receive beam strengths at the network device associated with the remainder of the first set of beams with respect to the uplink reference signal, and one or more second receive beam strengths at the network device associated with the remainder of the second set of beams with respect to the uplink reference signal, wherein the first receive beam strength is the greatest receive beam strength relative to the one or more first receive beam strengths, and wherein the second receive beam strength is the greatest receive beam strength relative to the one or more second receive beam strengths.
16. The apparatus of claim 11 , wherein the one or more processors are configured to execute the instructions to cause the UE to:
communicate with the network device via at least one non-line-of-sight communication path via one or both of the first transmit beam and the second transmit beam.
17. The apparatus of claim 11 , wherein, to receive the beam report, the one or more processors are configured to execute the instructions to cause the UE to:
identify, in the beam report, an indication of a first reference signal receive power value associated with use of the first transmit beam and the second transmit beam, wherein the first reference signal receive power value is greater than a second reference signal receive power value associated with use of a pre-configured transmit beam pair.
18. The apparatus of claim 11 , wherein the first polarization comprises a horizontal polarization and the second polarization comprises a vertical polarization.
19. The apparatus of claim 11 , wherein the uplink reference signal comprises a sounding reference signal.
20. The apparatus of claim 11 , wherein:
the beamforming codebook is for multiple-input multiple-output communication; and
the UE and the network device communicate over a millimeter wave radio frequency spectrum band.
21. A method for wireless communication at a user equipment (UE), comprising:
receiving a downlink reference signal from a network device;
selecting, from a beamforming codebook and based at least in part on historical information stored at the UE that indicates one or more performance statistics associated with beams in the beamforming codebook, a first receive beam and a second receive beam to be measured for receive beam strength with respect to the downlink reference signal, the first receive beam being selected from a first set of beams associated with a first polarization in the beamforming codebook and the second receive beam being selected from a second set of beams associated with a second polarization in the beamforming codebook in accordance with the one or more performance statistics associated with the beams in the beamforming codebook;
measuring, based at least in part on selecting the first receive beam and the second receive beam, a receive strength of the downlink reference signal on both the first receive beam and the second receive beam; and
transmitting, to the network device, a beam report that identifies the first receive beam and the second receive beam.
22. The method of claim 21 , wherein selecting the first receive beam and the second receive beam comprises:
selecting the first receive beam independent of the second receive beam.
23. The method of claim 21 , wherein selecting the first receive beam and the second receive beam comprises:
selecting the first receive beam from the first set of beams and the second receive beam from the second set of beams based at least in part on the first receive beam and the second receive beam each having a greatest receive beam strength with respect to the downlink reference signal relative to a remainder of the first set of beams and the second set of beams, respectively, in accordance with the one or more performance statistics associated with the beams in the beamforming codebook.
24. The method of claim 23 , wherein the historical information stored at the UE indicates, via the one or more performance statistics associated with the beams in the beamforming codebook, that the first receive beam and the second receive beam each have had the greatest receive beam strength with respect to the downlink reference signal relative to the remainder of the first set of beams and the second set of beams, respectively.
25. The method of claim 23 , wherein the one or more performance statistics include a first receive beam strength associated with the first receive beam with respect to the downlink reference signal, a second receive beam strength associated with the second receive beam with respect to the downlink reference signal, one or more first receive beam strengths associated with the remainder of the first set of beams with respect to the downlink reference signal, and one or more second receive beam strengths associated with the remainder of the second set of beams with respect to the downlink reference signal, wherein the first receive beam strength is the greatest receive beam strength relative to the one or more first receive beam strengths, and wherein the second receive beam strength is the greatest receive beam strength relative to the one or more second receive beam strengths.
26. A method for wireless communication at a user equipment (UE), comprising:
selecting, from a beamforming codebook and based at least in part on historical information stored at the UE that indicates one or more performance statistics associated with beams in the beamforming codebook, a first transmit beam and a second transmit beam for transmission of an uplink reference signal, the first transmit beam being selected from a first set of beams associated with a first polarization in the beamforming codebook and the second transmit beam being selected from a second set of beams associated with a second polarization in the beamforming codebook in accordance with the one or more performance statistics associated with the beams in the beamforming codebook;
transmitting, based at least in part on selecting the first transmit beam and the second transmit beam, the uplink reference signal to a network device via both the first transmit beam and the second transmit beam; and
receiving, from the network device, a beam report based at least in part on the transmission of the uplink reference signal via the first transmit beam and the second transmit beam.
27. The method of claim 26 , wherein selecting the first transmit beam and the second transmit beam comprises:
selecting the first transmit beam independent of the second transmit beam.
28. The method of claim 26 , wherein selecting the first transmit beam and the second transmit beam comprises:
selecting the first transmit beam from the first set of beams and the second transmit beam from the second set of beams based at least in part on the first transmit beam and the second transmit beam each having a greatest receive beam strength at the network device with respect to the uplink reference signal relative to a remainder of the first set of beams and the second set of beams, respectively, in accordance with the one or more performance statistics associated with the beams in the beamforming codebook.
29. The method of claim 28 , wherein the historical information stored at the UE indicates, via the one or more performance statistics associated with the beams in the beamforming codebook, that the first transmit beam and the second transmit beam each have the greatest receive beam strength at the network device with respect to the uplink reference signal relative to the remainder of the first set of beams and the second set of beams, respectively.
30. The method of claim 28 , wherein the one or more performance statistics include a first receive beam strength at the network device associated with the first transmit beam with respect to the uplink reference signal, a second receive beam strength at the network device associated with the second transmit beam with respect to the uplink reference signal, one or more first receive beam strengths at the network device associated with the remainder of the first set of beams with respect to the uplink reference signal, and one or more second receive beam strengths at the network device associated with the remainder of the second set of beams with respect to the uplink reference signal, wherein the first receive beam strength is the greatest receive beam strength relative to the one or more first receive beam strengths, and wherein the second receive beam strength is the greatest receive beam strength relative to the one or more second receive beam strengths.