Method and device for RIS automatic setup

1. A method by a user equipment (UE) in a wireless communication system, the method comprising:

receiving reconfigurable intelligent surface (RIS) information from an RIS controller (RC);

identifying an incident beam incident on the UE;

providing information about the identified incident beam to the RC and requesting information about candidate RIS modes;

receiving the information about the candidate RIS modes;

performing probing on the candidate RIS modes;

deriving a final RIS mode among the candidate RIS modes using a result of the probing; and

transmitting information about the final RIS mode to an RIS through the RC.

2. The method of claim 1 ,

wherein the RIS information is information including an identifier (ID) of the RIS, and

wherein the information about the candidate RIS modes includes a list of candidate RIS modes classified per incident beam.

3. The method of claim 1 , further comprising:

performing probing from a candidate RIS mode having a largest beam width of reflection beam among the candidate RIS modes;

selecting a candidate RIS mode having a largest reception signal strength among first probed candidate RIS modes; and

performing probing on a candidate RIS mode similar in direction of reflection beam to the selected candidate RIS mode and narrower in beam width of reflection beam than the selected candidate RIS mode.

4. The method of claim 3 , wherein the candidate RIS modes are arranged in a tree-shaped hierarchical structure based on beam width and beam direction and are probed in order from a higher layer.

5. The method of claim 1 ,

wherein the RIS information includes information about a machine learning (ML) model using an RIS mode with a largest reception signal strength among the candidate RIS modes as a result value, and

wherein the final RIS mode is derived as a result value obtained by inputting a candidate RIS mode corresponding to an incident beam identified by the UE to the ML model.

6. The method of claim 5 , wherein the ML model used to derive the final RIS mode is trained per incident beam pattern.

7. The method of claim 6 , further comprising:

capturing the RIS;

estimating a relative position between the UE and the RIS based on the captured RIS;

recognizing the estimated position as a shadow area of the UE; and

deriving a candidate RIS mode corresponding to the shadow area among the candidate RIS modes, as the final RIS mode.

8. The method of claim 7 , wherein the final RIS mode is derived based on the relative position between the UE and the RIS, and the incident beam pattern.

9. A method by a reconfigurable intelligent surface (RIS) in a wireless communication system, the method comprising:

receiving a request for channel estimation from an RIS controller (RC);

identifying incident beams incident from a base station to the RIS;

transmitting channel information about an incident beam having a largest reception strength among the incident beams to the RC;

receiving information about an optimal RIS mode derived by a user equipment (UE) through the RC; and

setting the RIS as the optimal RIS mode.

10. The method of claim 9 ,

wherein the RIS is a device reflecting a signal transmitted from a base station or a UE to be received by the UE or the base station,

wherein the RIS determines an amplitude and phase of a signal reflected in at least one or more RIS unit cells,

wherein the final RIS mode is a combination of respective states of the at least one or more RIS unit cells,

wherein the final RIS mode is pre-configured by a manufacturer, and

wherein information about the final RIS mode is stored in the RC.

11. A user equipment (UE) in a wireless communication system, the UE comprising:

a transceiver; and

at least one processor configured to:

receive reconfigurable intelligent surface (RIS) information from an RIS controller (RC) through the transceiver,

identify an incident beam incident on the UE,

provide information about the identified incident beam to the RC through the transceiver and request information about candidate RIS modes,

receive the information about the candidate RIS modes through the transceiver,

perform probing on the candidate RIS modes,

derive a final RIS mode among the candidate RIS modes using a result of the probing, and

transmit, through the transceiver, information about the final RIS mode to an RIS through the RC.

12. The UE of claim 11 ,

wherein the RIS information is information including an identifier (ID) of the RIS, and

wherein the information about the candidate RIS modes includes a list of candidate RIS modes classified per incident beam.

13. The UE of claim 11 , wherein the at least one processor is further configured to:

perform probing from a candidate RIS mode having a largest beam width of reflection beam among the candidate RIS modes,

select a candidate RIS mode having a largest reception signal strength among first probed candidate RIS modes, and

performing probing on a candidate RIS mode similar in direction of reflection beam to the selected candidate RIS mode and narrower in beam width of reflection beam than the selected candidate RIS mode.

14. The UE of claim 13 , wherein the candidate RIS modes are arranged in a tree-shaped hierarchical structure based on beam width and beam direction and are probed in order from a higher layer.

15. The UE of claim 11 ,

wherein the RIS information includes information about an ML model using an RIS mode with a largest reception signal strength among the candidate RIS modes as a result value, and

wherein the final RIS mode is derived as a result value obtained by inputting a candidate RIS mode corresponding to an incident beam identified by the UE to the ML model.

16. The UE of claim 15 , wherein the ML model used to derive the final RIS mode is trained per incident beam pattern.

17. The UE of claim 16 , wherein the at least one processor is further configured to:

capture the RIS,

estimate a relative position between the UE and the RIS based on the captured RIS,

recognize the estimated position as a shadow area of the UE, and

derive a candidate RIS mode corresponding to the shadow area among the candidate RIS modes, as the final RIS mode.

18. The UE of claim 17 , wherein the at least one processor is further configured to derive the final RIS mode based on the relative position between the UE and the RIS and the incident beam pattern.

19. A reconfigurable intelligent surface (RIS) in a wireless communication system, the RIS comprising:

a transceiver; and

at least one processor configured to:

receive a request for channel estimation from an RIS controller (RC) through the transceiver,

identify incident beams incident from a base station to the RIS,

transmit, through the transceiver, channel information about an incident beam having a largest reception strength among the incident beams to the RC,

receive, through the transceiver, information about a final RIS mode derived by a user equipment (UE) through the RC, and

set the RIS as the final RIS mode.

20. The RIS of claim 19 ,

wherein the RIS is a device reflecting a signal transmitted from a base station or a UE to be received by the UE or the base station,

wherein the RIS determines an amplitude and phase of a signal reflected in at least one or more RIS unit cells,

wherein the final RIS mode is a combination of respective states of the at least one or more RIS unit cells,

wherein the final RIS mode is set by a manufacturer in advance, and

wherein information about the final RIS mode is stored in the RC.