Multiple-input, multiple-output transmissions using adaptive phase- changing devices

1 . A method performed by a base station for communicating with multiple user equipments (UEs) in a wireless network using multiple-input, multiple-output (MIMO) transmissions and a first adaptive phase-changing device (APD) the method comprising:

selecting the first APD to use in at least one communication path for the MIMO transmissions;

selecting a first UE and a second UE for multiple user-MIMO (MU-MIMO) communication;

performing a channel characterization process for the at least one communication path using the first APD and the first UE and second UE;

configuring the first APD for the MIMO transmissions based on the channel characterization process, the configuring comprising:

coordinating application of concurrent phase vectors to be applied by the first APD such that:

a first APD-surface-partition is time-aligned with Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH) transmissions between the first UE and the base station; and

a second APD-surface-partition is time-aligned with PDSCH and PUSCH transmissions between the second UE and the base station;

communicating with the first UE using a first MIMO transmission of the MIMO transmissions and including the first APD-surface-partition in a first communication path for the first MIMO transmission; and

communicating with the second UE using a second MIMO transmission of the MIMO transmissions and by including the second APD-surface-partition in a second communication path for the second MIMO transmission.

2 . The method as recited in claim 1 , wherein the performing of the channel characterization process comprises:

transmitting one or more channel state information reference signals (CSI-RSs) towards a respective surface of the first APD; or

receiving one or more sounding reference signals (SRSs) from the UEs using the respective surface of the first APD.

3 . The method as recited in claim 2 , wherein the performing of the channel characterization process comprises:

in response to transmitting the one or more CSI-RSs, receiving one or more respective downlink signal or link quality measurements from the UEs; or

in response to receiving the one or more SRSs, generating one or more respective uplink signal or link quality measurements;

wherein the configuring of the first APD for the MIMO transmissions based on the channel characterization process comprises:

analyzing at least one of:

the one or more respective downlink signal or link quality measurements; or

the one or more respective uplink signal or link quality measurements; and

selecting, based on the analyzing, a surface configuration for the first APD.

4 . The method as recited in claim 2 , wherein the performing of the channel characterization process comprises:

selecting, for the first APD, a respective beam-sweeping pattern to apply during the channel characterization process;

directing the first APD to apply the respective beam-sweeping pattern during the channel characterization process; and

assigning a MIMO transmission configuration to a respective surface configuration;

wherein the configuring of the first APD comprises:

identifying MIMO transmission configurations for the MIMO transmissions based on the channel characterization process and the assigning, and

wherein the communicating with the first UE and communicating with the second UE comprises:

communicating using the MIMO transmission configurations for the MIMO transmissions.

5 . The method as recited in claim 4 wherein the performing of the channel characterization process comprises:

associating each CSI-RS of the one or more CSI-RSs to a respective surface configuration included in the respective beam-sweeping pattern; or

associating each SRS of the one or more SRSs to the respective surface configuration included in the respective beam-sweeping pattern.

6 . The method as recited in claim 1 , wherein the configuring of the first APD for the MIMO transmissions comprises:

indicating an APD timing adjustment to the first APD; and

directing the first APD to apply a surface configuration using a respective APD timing adjustment.

7 . The method as recited in claim 6 , further comprising:

determining the APD timing adjustment based on at least one of:

a physical downlink shared channel (PDSCH) MIMO transmission time;

a physical uplink shared channel (PUSCH) MIMO transmission time;

a respective location of each UE of the UEs; or

a location of the first APD.

8 . The method as recited in claim 6 , wherein the indicating of the APD timing adjustment to the first APD comprises:

communicating the APD timing adjustment to the first APD using an APD control channel that utilizes frequency transmissions in a frequency band that is lower than a frequency band of the MIMO transmissions.

9 . The method as recited in claim 6 , wherein the configuring of the first APD for the MIMO transmissions comprises:

calculating a first timing advance value for the first UE; and

calculating a second timing advance value for the second UE;

wherein the indicating the APD timing adjustment to the first APD is based at least in part on the first timing advance value or the second timing advance value.

10 . The method as recited in claim 1 , wherein:

the configuring of the first APD for the MIMO transmissions comprises at least one of:

selecting a first surface configuration for the first APD-surface-partition of the first APD based, at least in part, on a first MU-MIMO transmission configuration specific to the first UE; or

selecting a second surface configuration for the second APD-surface-partition of the first APD based, at least in part, on a second MU-MIMO transmission configuration specific to the second UE.

11 . The method as recited in claim 1 , wherein the communicating with the first UE and communicating with the second UE comprises:

simultaneously communicating with the first UE and second UE.

12 . The method as recited in claim 1 , wherein the communicating with the first UE comprises:

communicating user-plane data with the first UE; and

wherein the communicating with the second UE comprises:

communicating user-plane data with the second UE.

13 . The method as recited in claim 1 , wherein the communicating with the first UE comprises:

communicating control-plane information with the first UE; and

wherein the communicating with the second UE comprises:

communicating control-plane information with the second UE.

14 . A base station comprising:

at least one wireless transceiver;

at least one processor; and

computer-readable storage media comprising instructions executable by the at least one processor, to direct the base station to:

select a first adaptive phase-changing device (APD) to use in at least one communication path for multiple-input, multiple-output (MIMO) transmissions;

select a first UE and a second UE for multiple user-MIMO (MU-MIMO) communication;

perform a channel characterization process for the at least one communication path using the first APD and the first UE and second UE;

configure the first APD for the MIMO transmissions based on the channel characterization process, the configuration directing the base station to:

coordinate application of concurrent phase vectors to be applied by the first APD such that:

a first APD-surface-partition is time-aligned with Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH) transmissions between the first UE and the base station; and

a second APD-surface-partition is time-aligned with PDSCH and PUSCH transmissions between the second UE and the base station;

communicate with the first UE using a first MIMO transmission of the MIMO transmissions and including the first APD-surface-partition in a first communication path for the first MIMO transmission; and

communicate with the second UE using a second MIMO transmission of the MIMO transmissions and by including the second APD-surface-partition in a second communication path for the second MIMO transmission.

15 . The base station as recited in claim 14 , wherein the instructions to perform the channel characterization process are executable to direct the base station to:

transmit one or more channel state information reference signals (CSI-RSs) towards a respective surface of the first APD; or

receive one or more sounding reference signals (SRSs) from the UEs using the respective surface of the first APD.

16 . The base station as recited in claim 15 , wherein the instructions to perform of the channel characterization process are executable to direct the base station to:

in response to the transmission of the one or more CSI-RSs, receive one or more respective downlink signal or link quality measurements from the UEs; or

in response to the reception of the one or more SRSs, generate one or more respective uplink signal or link quality measurements;

wherein the configuration of the first APD for the MIMO transmissions based on the channel characterization process comprises:

analyzing at least one of:

the one or more respective downlink signal or link quality measurements; or

the one or more respective uplink signal or link quality measurements; and

selecting, based on the analyzing, a surface configuration for the first APD.

17 . The base station as recited in claim 15 , wherein the instructions to perform the channel characterization process are executable to direct the base station to:

select, for the first APD, a respective beam-sweeping pattern to apply during the channel characterization process;

direct the first APD to apply the respective beam-sweeping pattern during the channel characterization process; and

assign a MIMO transmission configuration to a respective surface configuration;

wherein the configuration of the first APD comprises:

identifying MIMO transmission configurations for the MIMO transmissions based on the channel characterization process and the assigning, and

wherein the communication with the first UE and communicating with the second UE comprises:

communicating using the MIMO transmission configurations for the MIMO transmissions.

18 . The base station as recited in claim 17 , wherein the instructions to perform the channel characterization process are executable to direct the base station to:

associate each CSI-RS of the one or more CSI-RSs to a respective surface configuration included in the respective beam-sweeping pattern; or

associate each SRS of the one or more SRSs to the respective surface configuration included in the respective beam-sweeping pattern.

19 . The base station as recited in claim 14 , wherein the instructions to configure the first APD for the MIMO transmissions are executable to direct the base station to:

indicate an APD timing adjustment to the first APD; and

direct the first APD to apply a surface configuration using a respective APD timing adjustment.

20 . The base station as recited in claim 19 , the instructions executable to direct the base station to:

determine the APD timing adjustment based on at least one of:

a physical downlink shared channel (PDSCH) MIMO transmission time;

a physical uplink shared channel (PUSCH) MIMO transmission time;

a respective location of each UE of the UEs; or

a location of the first APD, and

wherein the instructions to indicate the APD timing adjustment to the first APD are executable to direct the base station to:

communicate the APD timing adjustment to the first APD using an APD control channel that utilizes frequency transmissions in a frequency band that is lower than a frequency band of the MIMO transmissions.