Uplink timing and frequency offset estimation and compensation for CSI estimation and tracking

1. A base station (BS) in a wireless communication system, the BS comprising:

a transceiver configured to receive a set of uplink signals; and

a processor operably connected to the transceiver, the processor configured to:

estimate, based on a subset of the set of uplink signals, uplink channels,

estimate a timing offset (TO) and a frequency offset (FO) for a subset of the estimated uplink channels, wherein the TO is identified in a TO range,

compensate, based on the estimated TO and FO, the subset of the estimated uplink channels to generate TO and FO compensated uplink channel estimates, and

generate channel prediction information based on the compensated subset of the estimated uplink channels.

2. The BS of claim 1 , wherein:

the set of uplink signals comprises first uplink signals that are stored in a buffer;

the transceiver is further configured to receive second uplink signals including the subset of the set of uplink signals after receipt of the first uplink signals; and

the processor is further configured to predict a reference signal based on a portion of past history of the TO and FO compensated uplink channel estimates.

3. The BS of claim 2 , wherein the processor is further configured to:

identify, based on the second uplink signals, an operation mode of the second uplink signals to compensate the FO;

select a reference channel based on information of the first uplink signals and the estimated uplink channels to track a TO estimation and an FO estimation; and

select a location of the TO from the first uplink signals or the second uplink signals to track a TO compensation and an FO compensation.

4. The BS of claim 3 , wherein the operation mode comprises a frequency non-hopped SRS mode using a whole bandwidth for the FO compensation and a frequency-hopped SRS mode using a fraction of the whole bandwidth for the FO compensation.

5. The BS of claim 4 , wherein the processor is further configured to enable, using a set of adjacent edge resource blocks (ERBs) in the fraction of the whole bandwidth, an ERB stitching operation for the FO compensation.

6. The BS of claim 1 , wherein:

the transceiver is further configured to receive a physical uplink control channel (PUCCH); and

the processor is further configured to:

identify a PUCCH format of the PUCCH, and

decode, based on the PUCCH format, a hybrid automatic repeat request-acknowledgement (HARQ-ACK) included in the PUCCH.

7. The BS of claim 6 , wherein the processor is further configured to:

convert a symbol for the HARQ-ACK to a demodulation reference signal (DMRS) of the PUCCH;

estimate the TO and the FO based on the DMRS of the PUCCH; and

generate the channel prediction information based on the DMRS of the PUCCH and the compensated subset of the estimated uplink channels.

8. The BS of claim 1 , wherein the processor is further configured to identify a selection metric to select a reference channel, the selection metric being determined based on an operation mode of the subset of the set of uplink signals and a speed of a user equipment (UE).

9. The BS of claim 1 , wherein the processor is further configured to:

identify the TO range to select a location of TO, the TO range being a time interval for tracking a TO compensation and an FO compensation;

identify a threshold to determine whether the TO range is greater than the threshold; and

select the location of TO from the set of uplink signals based on a determination that the TO range is greater than the threshold.

10. The BS of claim 1 , wherein the processor is further configured to:

identify the set of uplink signals received through all antennas that are configured at the BS; and

track a TO estimation and an FO estimation based on an operation mode of the set of uplink signals received through all antennas.

11. A method of a base station (BS) in a wireless communication system, the method comprising:

receiving a set of uplink signals;

estimating, based on a subset of the set of uplink signals, uplink channels;

estimating a timing offset (TO) and a frequency offset (FO) for a subset of the estimated uplink channels, wherein the TO is identified in a TO range;

compensating, based on the estimated TO and FO, the subset of the estimated uplink channels to generate TO and FO compensated uplink channel estimates; and

generating channel prediction information based on the compensated subset of the estimated uplink channels.

12. The method of claim 11 , further comprising:

receiving second uplink signals including the subset of the set of uplink signals after receipt of first uplink signals; and

predicting a reference signal based on a portion of past history of the TO and FO compensated uplink channel estimates, wherein the set of uplink signals comprises the first uplink signals that are stored in a buffer.

13. The method of claim 12 , further comprising:

identifying, based on the second uplink signals, an operation mode of the second uplink signals to compensate the FO;

selecting a reference channel based on information of the first uplink signals and the estimated uplink channels to track a TO estimation and an FO estimation; and

selecting a location of the TO from the first uplink signals or the second uplink signals to track a TO compensation and an FO compensation.

14. The method of claim 13 , wherein the operation mode comprises a frequency non-hopped SRS mode using a whole bandwidth for the FO compensation and a frequency-hopped SRS mode using a fraction of the whole bandwidth for the FO compensation.

15. The method of claim 14 , further comprising enabling, using a set of adjacent edge resource blocks (ERBs) in the fraction of the whole bandwidth, an ERB stitching operation for the FO compensation.

16. The method of claim 11 , further comprising:

receiving a physical uplink control channel (PUCCH);

identifying a PUCCH format of the PUCCH; and

decoding, based on the PUCCH format, a hybrid automatic repeat request-acknowledgement (HARQ-ACK) included in the PUCCH.

17. The method of claim 16 , further comprising:

converting a symbol for the HARQ-ACK to a demodulation reference signal (DMRS) of the PUCCH;

estimating the TO and the FO based on the DMRS of the PUCCH; and

generating the channel prediction information based on the DMRS of the PUCCH and the compensated subset of the estimated uplink channels.

18. The method of claim 11 , further comprising identifying a selection metric to select a reference channel, wherein the selection metric is determined based on an operation mode of the subset of the set of uplink signals and a speed of a user equipment (UE).

19. The method of claim 11 , further comprising:

identifying the TO range to select a location of TO, the TO range being a time interval for tracking a TO compensation and an FO compensation;

identifying a threshold to determine whether the TO range is greater than the threshold; and

selecting the location of TO from the set of uplink signals based on a determination that the TO range is greater than the threshold.

20. The method of claim 11 , further comprising:

identifying the set of uplink signals received through all antennas that are configured at the BS; and

tracking a TO estimation and an FO estimation based on an operation mode of the set of uplink signals received through all antennas.