Method and apparatus for communications in a distributed antenna system

1. A user equipment (UE), comprising:

a transceiver configured to receive:

a first configuration for measuring a channel difference between a target cell and a reference cell in a cell group; and

a second configuration for reporting the channel difference between the target cell and the reference cell in the cell group; and

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

determine, based on the first configuration, the channel difference between the target cell and the reference cell in the cell group,

wherein the transceiver is further configured to transmit, based on the second configuration, a channel difference report associated with the determined channel difference, and

wherein:

the channel difference report is (i) multiplexed in a channel state information (CSI) report or (ii) reported as a standalone CSI parameter in the CSI report, and

one of:

the CSI report is a wideband (WB) CSI report and the channel difference report is multiplexed at least with one or more CSI parameters in the WB CSI report; and

the CSI report is a narrowband (NB) CSI report and the channel difference report is multiplexed at least with one or more CSI parameters including a channel quality indicator (CQI), a rank indicator (RI) a precoding matrix indicator (PMI), or a layer indicator (LI) of the NB CSI report.

2. The UE of claim 1 , wherein the first configuration includes at least one of:

a number of cells in the cell group;

an entity identifier (ID) of the target cell in the cell group;

an entity ID of the reference cell in the cell group; and

a cell group ID associated with the cell group, and

wherein the entity ID of the target cell or the reference cell corresponds to at least one of: a physical cell ID (PCI), a CORESETPoolIndex value, a PCI index pointing to a PCI in a list of PCIs that are higher layer configured to the UE, and a cell index pointing to a cell in the cell group.

3. The UE of claim 1 , wherein:

the channel difference corresponds to at least one of:

a frequency shift difference between the target cell and the reference cell in the cell group;

a Doppler shift difference between the target cell and the reference cell in the cell group; and

a downlink (DL) timing difference between the target cell and the reference cell in the cell group.

4. The UE of claim 1 , wherein:

the second configuration includes time and frequency resource configurations in a channel state information (CSI) reporting setting for reporting the channel difference, and

the channel difference is configured as a report quantity in addition to a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and a layer indicator (LI).

5. The UE of claim 1 , wherein:

the channel difference report includes at least one of:

a frequency shift of the reference cell;

a frequency shift difference between the target and reference cells;

a Doppler shift of the reference cell;

a Doppler shift difference between the target and reference cells;

a downlink (DL) timing of the reference cell;

a DL timing difference between the target and reference cells;

a sign indicator for the frequency shift difference;

a sign indicator for the Doppler shift difference; and

a sign indicator for the DL timing difference, and

the channel difference report is part of a channel state information (CSI) report, multiplexed with hybrid automatic repeat request acknowledgement (HARQ-ACK) information, or multiplexed with a scheduling request (SR).

6. The UE of claim 1 , wherein:

the transceiver is further configured to receive an uplink (UL) timing advance (TA) command for the cell group; and

the UL TA command (i) is received via a random access response (RAR) or an absolute TA medium access control (MAC) control element (CE) and (ii) includes a TA group identifier (ID),

where the TA group ID corresponds to at least one of:

a cell group ID;

a physical cell ID (PCI);

a CORESETPoolIndex value;

a PCI index pointing to a PCI in a list of PCIs higher layer configured to the UE; and

a cell index pointing to a cell in the cell group.

7. A base station (BS), comprising:

a transceiver configured to:

transmit a first configuration to indicate measurement of a channel difference between a target cell and a reference cell in a cell group;

transmit a second configuration for reporting the channel difference between the target cell and the reference cell in the cell group; and

receive, based on the second configuration, a channel difference report associated with the channel difference,

wherein:

the channel difference report is (i) multiplexed in a channel state information (CSI) report or (ii) reported as a standalone CSI parameter in the CSI report, and

one of:

the CSI report is a wideband (WB) CSI report and the channel difference report is multiplexed at least with one or more CSI parameters in the WB CSI report; and

the CSI report is a narrowband (NB) CSI report and the channel difference report is multiplexed at least with one or more CSI parameters including a channel quality indicator (CQI), a rank indicator (RI) a precoding matrix indicator (PMI), or a layer indicator (LI) of the NB CSI report.

8. The BS of claim 7 , wherein the first configuration includes at least one of:

a number of cells in the cell group;

an entity identifier (ID) of the target cell in the cell group;

an entity ID of the reference cell in the cell group; and

a cell group ID associated with the cell group, and

wherein the entity ID of the target cell or the reference cell corresponds to at least one of: a physical cell ID (PCI), a CORESETPoolIndex value, a PCI index pointing to a PCI in a list of PCIs that are higher layer configured, and a cell index pointing to a cell in the cell group.

9. The BS of claim 7 , wherein:

the channel difference corresponds to at least one of:

a frequency shift difference between the target cell and the reference cell in the cell group;

a Doppler shift difference between the target cell and the reference cell in the cell group; and

a downlink (DL) timing difference between the target cell and the reference cell in the cell group.

10. The BS of claim 7 , wherein:

the second configuration includes time and frequency resource configurations in a channel state information (CSI) reporting setting for reporting the channel difference, and

the channel difference is configured as a report quantity in addition to a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and a layer indicator (LI).

11. The BS of claim 7 , wherein:

the channel difference report includes at least one of:

a frequency shift of the reference cell;

a frequency shift difference between the target and reference cells;

a Doppler shift of the reference cell;

a Doppler shift difference between the target and reference cells;

a downlink (DL) timing of the reference cell;

a DL timing difference between the target and reference cells;

a sign indicator for the frequency shift difference;

a sign indicator for the Doppler shift difference; and

a sign indicator for the DL timing difference, and

the channel difference report is part of a channel state information (CSI) report, multiplexed with hybrid automatic repeat request acknowledgement (HARQ-ACK) information, or multiplexed with a scheduling request (SR).

12. The BS of claim 7 , wherein:

the transceiver is further configured to transmit an uplink (UL) timing advance (TA) command for the cell group; and

the UL TA command (i) is transmitted via a random access response (RAR) or an absolute TA medium access control (MAC) control element (CE) and (ii) includes a TA group identifier (ID),

where the TA group ID corresponds to at least one of:

a cell group ID;

a physical cell ID (PCI);

a CORESETPoolIndex value;

a PCI index pointing to a PCI in a list of PCIs higher layer configured; and

a cell index pointing to a cell in the cell group.

13. A method for operating a user equipment (UE), the method comprising:

receiving a first configuration for measuring a channel difference between a target cell and a reference cell in a cell group;

receiving a second configuration for reporting the channel difference between the target cell and the reference cell in the cell group;

determining, based on the first configuration, the channel difference between the target cell and the reference cell in the cell group; and

transmitting, based on the second configuration, a channel difference report associated with the determined channel difference,

wherein:

the channel difference report is (i) multiplexed in a channel state information (CSI) report or (ii) reported as a standalone CSI parameter in the CSI report, and

one of:

the CSI report is a wideband (WB) CSI report and the channel difference report is multiplexed at least with one or more CSI parameters in the WB CSI report; and

the CSI report is a narrowband (NB) CSI report and the channel difference report is multiplexed at least with one or more CSI parameters including a channel quality indicator (CQI), a rank indicator (RI) a precoding matrix indicator (PMI), or a layer indicator (LI) of the NB CSI report.

14. The method of claim 13 , wherein the first configuration includes at least one of:

a number of cells in the cell group;

an entity identifier (ID) of the target cell in the cell group;

an entity ID of the reference cell in the cell group; and

a cell group ID associated with the cell group, and

wherein the entity ID of the target cell or the reference cell corresponds to at least one of: a physical cell ID (PCI), a CORESETPoolIndex value, a PCI index pointing to a PCI in a list of PCIs that are higher layer configured to the UE, and a cell index pointing to a cell in the cell group.

15. The method of claim 13 , wherein:

the channel difference corresponds to at least one of:

a frequency shift difference between the target cell and the reference cell in the cell group;

a Doppler shift difference between the target cell and the reference cell in the cell group; and

a downlink (DL) timing difference between the target cell and the reference cell in the cell group.

16. The method of claim 13 , wherein:

the second configuration includes time and frequency resource configurations in a channel state information (CSI) reporting setting for reporting the channel difference, and

the channel difference is configured as a report quantity in addition to a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and a layer indicator (LI).

17. The method of claim 13 , wherein:

the channel difference report includes at least one of:

a frequency shift of the reference cell;

a frequency shift difference between the target and reference cells;

a Doppler shift of the reference cell;

a Doppler shift difference between the target and reference cells;

a downlink (DL) timing of the reference cell;

a DL timing difference between the target and reference cells;

a sign indicator for the frequency shift difference;

a sign indicator for the Doppler shift difference; and

a sign indicator for the DL timing difference, and

the channel difference report is part of a channel state information (CSI) report, multiplexed with hybrid automatic repeat request acknowledgement (HARQ-ACK) information, or multiplexed with a scheduling request (SR).