Method for establishing wireless channel including downlink-oriented channel in wireless LAN system, and apparatus therefor
The present document relates to a wireless communication system and, more particularly, to a method for establishing a wireless channel by an AP in a high-density wireless LAN system and to an apparatus therefor. The AP configured for this purpose can establish a primary channel and one or more secondary channels, establish one or more downlink oriented channels into one or more secondary channels, but without the one or more downlink oriented channels overlapping the primary channel of an adjacent basic service set (BSS), and transmit, to a station connected to the AP, the frame including establishment information on the established one or more downlink oriented channels.
1. A method of establishing a wireless channel by an Access Point (AP) in a Wireless Local Area Network (WLAN) system, the method comprising;
establishing a primary channel and one or more secondary channels; and
configuring the one or more secondary channels as one or more downlink oriented channels,
wherein the one or more downlink oriented channels are configured not to overlap with a primary channel of an adjacent Basic Service Set (BSS), and a frame including configuration information about the one or more downlink oriented channels is transmitted to a Station (STA) associated with the AP,
wherein, if a first STA among STAs associated with the AP is located at a position not overlapped with an area of another BSS, the AP transmits data to the first STA on the one or more downlink oriented channels, and
wherein, if a second STA among the STAs associated with the AP is located at a position overlapped with the area of another BSS, the AP transmits data to the second STA on a normal channel other than the one or more downlink oriented channels.
2. The method according to claim 1 , further comprising:
transmitting a request message requesting information about the adjacent BSS to the STA associated with the AP; and
receiving a response message including information about the adjacent BSS from the STA associated with the AP.
3. The method according to claim 2 , wherein the request message requesting information about the adjacent BSS is broadcast or multicast to a plurality of STAs associated with the AP, and information about the adjacent BSS that one or more of the plurality of STAs have is received in response messages.
4. The method according to claim 2 or 3 , wherein the response message including the information about the adjacent BSS includes at least one of a BSS Identifier (BSSID), primary and secondary channel information, bandwidth information, downlink oriented channel information, and operating class of the adjacent BSS.
5. The method according to claim 1 , wherein the AP transmits data to the first STA on the one or more downlink oriented channels, without exchanging a Request To Send (RTS) frame and a Clear To Send (CTS) frame.
6. The method according to claim 5 , wherein the AP transmits data to the second STA on the normal channel other than the one or more downlink oriented channels, after exchanging the RTS frame and the CTS frame.
7. The method according to claim 1 , wherein if a data transmission state of a third STA among STAs associated with the AP is equal to or lower than a predetermined level, the AP transmits data to third first STA on a normal channel other that the one or more downlink oriented channels, or on the one or more downlink oriented channels after exchanging an RTS the RTS frame and the CTS frame.
8. The method according to claim 1 , wherein if the number of the one or more downlink oriented channels is 2 or larger, a first-type downlink oriented channel is configured for the first STA, and a second-type downlink oriented channel is configured for the second STA.
9. The method according to claim 8 , wherein the second-type downlink oriented channel is configured to be a different frequency channel from a second-type downlink oriented channel of the adjacent BSS.
10. The method according to claim 1 , wherein the AP determines whether each STA associated with the AP is located at a position overlapped with the area of another BSS by receiving a scanning result from the STA.
11. An Access Point (AP) for establishing a wireless channel in a Wireless Local Area Network (WLAN) system, the AP comprising;
a transceiver configured to transmit and receive signals to and from a Station (STA) associated with the AP; and
a controller connected to the transceiver and configured to establish a primary channel and one or more secondary channels, and configure the one or more secondary channels as one or more downlink oriented channels,
wherein the controller configures the one or more downlink oriented channels not to overlap with a primary channel of an adjacent Basic Service Set (BSS), and transmit a frame including configuration information about the one or more downlink oriented channels to an STA associated with the AP through the transceiver,
wherein, if a first STA among STAs associated with the AP is located at a position not overlapped with an area of another BSS, the controller controls the transceiver to transmit data to the first STA on the one or more downlink oriented channels, and
wherein, if a second STA among the STAs associated with the AP is located at a position overlapped with an area of another BSS, the controller controls the transceiver to transmit data to the second STA on a normal channel other than the one or more downlink oriented channels.