Method and apparatus for channel access via null data packet frame in wireless LAN system

A method for supporting channel access of a station (STA) by an access point (AP) of a wireless communication system, the method comprising:

• transmitting, to the STA, a beacon frame including a traffic indication map (TIM),
• wherein the TIM includes configuration information regarding at least one slot for channel access;
• transmitting a null data packet (NDP) frame to the STA at a specific slot from among the at least one slot;
• and
• initiating channel access by the STA after transmission of the NDP frame,
• wherein a power save-poll (PS-Poll) frame is transmitted from the STA to the AP when the channel access is initiated,
• wherein a data frame is transmitted based on the NDP frame from the AP after the PS-Poll frame is transmitted to the AP,
• wherein the configuration information regarding the at least one slot includes information regarding a time period in which channel access of the STA is allowed,
• wherein the NDP frame is a Physical Layer Packet Data Unit (PPDU) frame including a Short Training Field (STF), a Long Training Field (LTF), and a signal (SIG) field without inclusion of a data field, and
• wherein the SIG field includes information indicating an identifier (ID) of the STA.

A station (STA) device configured to perform channel access in a wireless communication system, comprising:

• a transceiver;
• and
• a processor that:
• controls the transceiver to receive, from an access point (AP), a beacon frame including a traffic indication map (TIM),
• wherein the TIM includes configuration information regarding at least one slot for channel access,
• controls the transceiver to receive a null data packet (NDP) frame from the AP at a specific slot from among the at least one slot, and
• initiates channel access after reception of the NDP frame,
• wherein a power save-poll (PS-Poll) frame is transmitted from the STA to the AP when the channel access is initiated,
• wherein a data frame is transmitted based on the NDP frame from the AP after the PS-Poll frame is transmitted to the AP,
• wherein the configuration information regarding the at least one slot includes information regarding a time period in which channel access of the STA is allowed,
• wherein the NDP frame is a Physical Layer Packet Data Unit (PPDU) frame including a Short Training Field (STF), a Long Training Field (LTF), and a signal (SIG) field without inclusion of a data field, and
• wherein the SIG field includes information indicating an identifier (ID) of the STA.

An access point (AP) device configured to support channel access of a station (STA) in a wireless communication system, comprising:

• a transceiver;
• and
• a processor that:
• controls the transceiver to transmit, to the STA, a beacon frame including a traffic indication map (TIM),
• wherein the TIM includes configuration information regarding at least one slot for channel access,
• controls the transceiver to transmit a null data packet (NDP) frame to the STA at a specific slot from among the at least one slot, and
• initiates channel access by the STA after transmission of the NDP frame,
• wherein a power save-poll (PS-Poll) frame is transmitted from the STA to the AP when the channel access is initiated,
• wherein a data frame is transmitted based on the NDP frame from the AP after the PS-Poll frame is transmitted to the AP,
• wherein the configuration information regarding the at least one slot includes information regarding a time period in which channel access of the STA is allowed,
• wherein the NDP frame is a Physical Layer Packet Data Unit (PPDU) frame including a Short Training Field (STF), a Long Training Field (LTF), and a signal (SIG) field without inclusion of a data field, and
• wherein the SIG field includes information indicating an identifier (ID) of the STA.