Method and device for preventing false PMI report in wireless communication system

1 . A wireless communication device comprising:

a communication circuit configured to receive a channel state information reference signal (CSI-RS);

a processor comprising an angle of departure (AoD) monitoring circuit and an interference cancellation circuit, wherein:

the AoD monitoring circuit is configured to extract AoD values corresponding to the CSI-RS, and

the interference cancellation circuit is configured to cancel second AoD values that correspond to an interfering cell adjacent to a serving cell, other than first AoD values corresponding to the serving cell among the AoD values; and

a memory storing the first AoD values corresponding to the serving cell and antenna array information of the serving cell,

wherein the antenna array information of the serving cell is obtained based on at least one of a medium access control (MAC) control element (CE) and downlink control information (DCI),

wherein the communication circuit is further configured to receive one or more CSI-RS in response to the wireless communication device enters an edge region of the serving cell, and

wherein the edge region of the serving cell covers at least a part of a coverage of the interfering cell.

2 . The wireless communication device of claim 1 ,

wherein the antenna array information of the serving cell is further obtained based on radio resource control (RRC) signaling.

3 . The wireless communication device of claim 1 , wherein the processor is configured to:

estimate an effective channel based on the first AoD values corresponding to the serving cell; and

determine a rank indicator (RI) and a channel quality indicator (CQI) based on the effective channel.

4 . The wireless communication device of claim 1 , wherein the processor is configured to:

generate precoding matrix indicator (PMI) candidates based on remaining AoD values except for the second AoD values corresponding to the interfering cell among the AoD values corresponding to the CSI-RS; and

select one PMI based on the PMI candidates.

5 . The wireless communication device of claim 1 , wherein the processor further comprises a handover decision circuit configured to:

calculate a first channel capacity of an effective channel that is estimated based on the first AoD values corresponding to the serving cell;

calculate a second channel capacity of an interference channel that is estimated based on the second AoD values corresponding to the interfering cell; and

transmit a handover request to the serving cell in response to that the second channel capacity is greater than the first channel capacity.

6 . The wireless communication device of claim 1 , wherein the processor is configured to:

generate a plurality of array response vectors respectively corresponding to a plurality of AoD values based on the antenna array information of the serving cell;

perform correlation analysis between a result of channel estimation for the CSI-RS and the plurality of array response vectors;

determine an AoD value having a highest degree of correlation based on the correlation analysis; and

select the AoD value for the serving cell.

7 . The wireless communication device of claim 1 , wherein the processor is configured to:

receive codebook information from the serving cell through radio resource control (RRC) signaling;

generate bases included in a precoding matrix indicator (PMI) codebook based on the codebook information;

perform correlation analysis between a result of channel estimation for the CSI-RS and the bases; and

determine a basis having a highest degree of correlation based on the correlation analysis as PMI basis for the serving cell.

8 . A method of operating a wireless communication device, the method comprising:

receiving a first channel state information reference signal (CSI-RS);

receiving a second CSI-RS in response to the wireless communication device enters an edge region of a serving cell;

extracting angle of departure (AoD) values corresponding to the first CSI-RS and the second CSI-RS;

classifying the AoD values into first AoD values corresponding to the serving cell and second AoD values corresponding to an interfering cell that is adjacent to the serving cell; and

receiving antenna array information of the serving cell from the serving cell,

wherein the antenna array information of the serving cell is obtained based on at least one of a medium access control (MAC) control element (CE) and downlink control information (DCI),

wherein the edge region of the serving cell covers at least a part of a coverage of the interfering cell.

9 . The method of claim 8 , further comprising:

receiving the antenna array information of the serving cell from the serving cell, wherein the antenna array information of the serving cell is further obtained based on radio resource control (RRC) signaling.

10 . The method of claim 8 , further comprising:

estimating an effective channel based on the first AoD values corresponding to the serving cell;

determining a rank indicator (RI) and a channel quality indicator (CQI) based on the effective channel; and

transmitting a CSI report comprising the RI and the CQI to the serving cell.

11 . The method of claim 8 , further comprising:

generating precoding matrix indicator (PMI) candidates based on remaining AoD values other than the second AoD values among the AoD values corresponding to the first CSI-RS;

selecting a PMI based on the PMI candidates; and

transmitting a CSI report comprising the PMI to the serving cell.

12 . The method of claim 8 , further comprising:

calculating a first channel capacity of an effective channel, wherein the first channel capacity is estimated based on the first AoD values corresponding to the serving cell;

calculating a second channel capacity of an interference channel, wherein the second channel capacity is estimated based on the second AoD values corresponding to the interfering cell; and

transmitting a handover request to the serving cell in response to that the second channel capacity is greater than the first channel capacity.

13 . The method of claim 8 , wherein the extracting of the AoD values corresponding to the CSI-RS comprises:

generating a plurality of array response vectors respectively corresponding to a plurality of AoD values based on antenna array information of the serving cell;

performing correlation analysis between a result of channel estimation for the CSI-RS and the plurality of array response vectors;

determining an AoD value having a highest degree of correlation based on the correlation analysis; and

selecting the AoD value with the highest degree of correlation as an AoD value for the serving cell.

14 . The method of claim 8 , further comprising:

receiving codebook information from the serving cell through radio resource control (RRC) signaling;

generating bases of a precoding matrix indicator (PMI) codebook based on the codebook information;

performing correlation analysis between a result of channel estimation for the first CSI-RS and the bases; and

determining a basis having a highest degree of correlation based on the correlation analysis as a PMI basis for the serving cell.

15 . A wireless communication system comprising:

a serving cell configured to transmit a first channel state information reference signal (CSI-RS) and antenna array information;

an interfering cell configured to transmit a second CSI-RS; and a wireless communication device configured to receive the first CSI-RS and the second CSI-RS, wherein the wireless communication device comprises:

a communication circuit configured to receive a CSI-RS comprising the first CSI-RS and the second CSI-RS;

a processor configured to extract AoD values corresponding to the CSI-RS and classify the AoD values into first AoD values corresponding to the serving cell and second AoD values corresponding to the interfering cell; and

a memory storing the first AoD values corresponding to the serving cell and the antenna array information of the serving cell,

wherein the antenna array information of the serving cell is obtained based on at least one of a medium access control (MAC) control element (CE) and downlink control information (DCI),

wherein the communication circuit is further configured to receive the second CSI-RS in response to the wireless communication device enters an edge region of the serving cell, and

wherein the edge region of the serving cell covers at least a part of a coverage of the interfering cell.

16 . The wireless communication system of claim 15 , wherein the wireless communication device is further configured to:

estimate an effective channel based on the first AoD values corresponding to the serving cell; and

determine a rank indicator (RI) and a channel quality indicator (CQI) based on the effective channel.

17 . The wireless communication system of claim 15 , wherein the wireless communication device is further configured to: generate precoding matrix indicator (PMI) candidates based on remaining AoD values except for the second AoD values corresponding to the interfering cell among the AoD values corresponding to the CSI-RS; and select one PMI based on the PMI candidates.

18 . The wireless communication system of claim 15 , wherein the wireless communication device is further configured to:

calculate a first channel capacity of an effective channel, wherein the first channel capacity is estimated based on the first AoD values corresponding to the serving cell;

calculate a second channel capacity of an interference channel, wherein the second channel capacity is estimated based on the second AoD values corresponding to the interfering cell; and

transmit a handover request to the serving cell in response to that the second channel capacity is greater than the first channel capacity.

19 . The wireless communication system of claim 17 , wherein the processor is further configured to:

generate a plurality of array response vectors respectively corresponding to a plurality of AoD values based on the antenna array information of the serving cell;

perform correlation analysis between a result of channel estimation for the CSI-RS and the plurality of array response vectors; and

determine an AoD value having a highest degree of correlation based on the correlation analysis to be an AoD value for the serving cell.

20 . The wireless communication system of claim 15 , wherein the antenna array information is further transmitted to the wireless communication device based on radio resource control (RRC) signaling.