Method and device for receiving signals by station in wireless communication system

A station (STA) for transmitting a signal in a wireless communication system, comprising:

• a transceiver module configured to exchange data with an external device and a processor configured to control the transceiver module,
• wherein the processor is configured to:
• receive, from an access point (AP) STA, a first frame for switching a power saving (PS) mode to an awake mode using the transceiver module;
• and
• transmit, to the AP STA, a second frame indicating the awake mode of the STA in response to the first frame, using the transceiver module,
• wherein the second frame is a Null Data Packet (NDP) frame.