Signal transmission/reception method in wireless LAN system, and device therefor

1. A method in a wireless LAN (WLAN) system, the method comprising:

transmitting, by a first station (STA), a Link Measurement Request frame requesting Transmit Power Control (TPC) information to a second STA; and

receiving, by the first STA, a Link Measurement Report frame from the second STA, the Link Measurement Report frame being transmitted as a response to the Link Measurement Request frame,

wherein the Link Measurement Request frame includes a TPC Configuration field,

wherein the TPC Configuration field includes a first sub-field and a second sub-field,

wherein the first sub-field includes information on whether or not the Link Measurement Request frame is transmitted through a channel on which channel aggregation is performed,

wherein the second sub-field includes information on a number of transmit chains being used for transmitting the Link Measurement Request frame, and

wherein, based on the Link Measurement Request frame being transmitted through the channel on which the channel aggregation is performed, the number of transmit chains is equal to an even number.

2. The method of claim 1 , wherein the Link Measurement Request frame further includes a Link Measurement Request field,

wherein the Link Measurement Request field includes a third sub-field and a fourth sub-field,

wherein the third sub-field includes information on a transmit power being used for each of the transmit chains, and

wherein the fourth sub-field includes information on a maximum transmit power for each of the transmit chains.

3. The method of claim 1 , wherein the Link Measurement Report frame includes a rate adaptation control or first TPC field, and

wherein the rate adaptation control or first TPC field includes information on a number of reported transmit chains.

4. The method of claim 3 , wherein the Link Measurement Report frame further includes a second TPC field,

wherein the second TPC field includes an Activity sub-field and a Link Margin sub-field on each of the reported transmit chains,

wherein the Activity sub-field includes recommended activities recommended to the first STA by the second STA for the reported transmit chains,

wherein information on the recommended operations is determined as one of No change preferred, Change MCS, Decrease transmit power, Increase transmit power, Fast session transfer, Power conserve mode, and Perform Sector Level Sweep (SLS), and

wherein the Link Margin sub-field includes information on a link margin for the first STA being measured by the second STA.

5. The method of claim 4 , wherein, if the information on the recommended operations is determined as No change preferred, the first STA does not change the transmit power of the transmit chain,

wherein, if the information on the recommended operations is determined as Decrease transmit power, the first STA decreases the transmit power of the transmit chain, and

wherein, if the information on the recommended operations is determined as Increase transmit power, the first STA increases the transmit power of the transmit chain.

6. The method of claim 4 , wherein the Link Measurement Report frame includes a Link Adaptation Acknowledgment element,

wherein the Link Adaptation Acknowledgment element includes an Activity sub-field, and

wherein the Activity sub-field includes information on an actual activity of the transmit chain after the first STA receives the recommended activities.

7. The method of claim 1 , wherein the channel on which the channel aggregation is performed is 2.16+2.16 GHz or 4.32+4.32 GHz.

8. A station (STA) device in a wireless LAN (WLAN) system, the STA device comprising:

a memory;

a transceiver; and

a processor being operatively connected to the memory and the transceiver, wherein the processor is configured:

to transmit a Link Measurement Request frame requesting Transmit Power Control (TPC) information to another STA; and

to receive a Link Measurement Report frame from the other STA, the Link Measurement Report frame being transmitted as a response to the Link Measurement Request frame,

wherein the Link Measurement Request frame includes a TPC Configuration field,

wherein the TPC Configuration field includes a first sub-field and a second sub-field,

wherein the first sub-field includes information on whether or not the Link Measurement Request frame is transmitted through a channel on which channel aggregation is performed,

wherein the second sub-field includes information on a number of transmit chains being used for transmitting the Link Measurement Request frame, and

wherein, based on the Link Measurement Request frame being transmitted through the channel on which the channel aggregation is performed, the number of transmit chains is equal to an even number.

9. The STA device of claim 8 , wherein the Link Measurement Request frame further includes a Link Measurement Request field,

wherein the Link Measurement Request field includes a third sub-field and a fourth sub-field,

wherein the third sub-field includes information on a transmit power being used for each of the transmit chains, and

wherein the fourth sub-field includes information on a maximum transmit power for each of the transmit chains.

10. The STA device of claim 8 , wherein the Link Measurement Report frame includes a rate adaptation control or first TPC field, and

wherein the rate adaptation control or first TPC field includes information on a number of reported transmit chains.

11. The STA device of claim 10 , wherein the Link Measurement Report frame further includes a second TPC field,

wherein the second TPC field includes an Activity sub-field and a Link Margin sub-field on each of the reported transmit chains,

wherein the Activity sub-field includes recommended activities recommended to the first STA by the second STA for the reported transmit chains,

wherein information on the recommended operations is determined as one of No change preferred, Change MCS, Decrease transmit power, Increase transmit power, Fast session transfer, Power conserve mode, and Perform Sector Level Sweep (SLS), and

wherein the Link Margin sub-field includes information on a link margin for the first STA being measured by the second STA.

12. The STA device of claim 11 , wherein, if the information on the recommended operations is determined as No change preferred, the first STA does not change the transmit power of the transmit chain,

wherein, if the information on the recommended operations is determined as Decrease transmit power, the first STA decreases the transmit power of the transmit chain, and

wherein, if the information on the recommended operations is determined as Increase transmit power, the first STA increases the transmit power of the transmit chain.

13. The STA device of claim 11 , wherein the Link Measurement Report frame includes a Link Adaptation Acknowledgment element,

wherein the Link Adaptation Acknowledgment element includes an Activity sub-field, and

wherein the Activity sub-field includes information on an actual activity of the transmit chain after the first STA receives the recommended activities.

14. The STA device of claim 8 , wherein the channel on which the channel aggregation is performed is 2.16+2.16 GHz or 4.32+4.32 GHz.

15. A method in a wireless LAN (WLAN) system, the method comprising:

receiving, by a first station (STA), a Link Measurement Request frame requesting Transmit Power Control (TPC) information from a second STA; and

transmitting, by the first STA, a Link Measurement Report frame to the second STA, the Link Measurement Report frame being transmitted as a response to the Link Measurement Request frame,

wherein the Link Measurement Request frame includes a TPC Configuration field,

wherein the TPC Configuration field includes a first sub-field and a second sub-field,

wherein the first sub-field includes information on whether or not the Link Measurement Request frame is transmitted through a channel on which channel aggregation is performed,

wherein the second sub-field includes information on a number of transmit chains being used for transmitting the Link Measurement Request frame, and

wherein, based on the Link Measurement Request frames being transmitted through the channel on which the channel aggregation is performed, the number of transmit chains is equal to an even number.