Communication method and apparatus using subchannel in wireless LAN

Abstract

The purpose of the present disclosure is to perform communication by using a subchannel in a wireless LAN system, and a method for operation of an access point (AP) comprises the steps of: detecting that another device other than a station (STA) connected to the AP performs communication on a primary channel; acquiring information related to a time duration in which the communication is performed; switching an operation channel from the primary channel to at least one subchannel during the time duration; transmitting or receiving data on the subchannel; and switching the operation channel to the primary channel.

Description

Communication method and device using subchannels in wireless LAN

[0001] The present invention relates to a wireless local area network (WLAN) system, and more particularly, to a communication method and device using a subchannel in a wireless LAN system.

[0002] With the recent proliferation of mobile devices, Wireless Local Area Network (WLAN) technology, which can provide fast wireless communication services to these devices, is attracting significant attention. WLAN technology utilizes short-range wireless communication technology to enable mobile devices such as smartphones, tablets, laptops, portable multimedia players, and embedded devices to wirelessly access the Internet.

[0003] As applications requiring higher throughput and real-time transmission emerge, wireless LANs can support expanded frequency bandwidth and / or efficient retransmission operations. Furthermore, operations utilizing multiple channels or links simultaneously can be supported.

[0004] Meanwhile, the technology that serves as the background for the invention is written to promote understanding of the background for the invention, and may include content that is not a prior art already known to a person with ordinary skill in the field to which the technology belongs.

[0005] The present disclosure provides a method and device for performing communication using a primary channel and a subchannel in a wireless LAN system.

[0006] The present disclosure provides a method and device for performing channel detection on a primary channel in a wireless LAN system and performing communication based on the channel detection result.

[0007] The present disclosure provides a method and device for performing communication using a subchannel when a main channel is being used by another device in a wireless LAN system.

[0008] The present disclosure provides a method and device for performing communication using a subchannel when the use of a main channel differs for each wireless LAN device in a wireless LAN system.

[0009] The present disclosure provides a method and device for performing communication when some subchannels are unavailable in a wireless LAN system.

[0010] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0011] According to one embodiment of the present disclosure, a method for operating an access point (AP) in a wireless LAN system includes the steps of: detecting that a device other than at least one STA connected to the AP performs communication on a primary channel; acquiring information related to a time period during which the communication is performed; performing an operating channel switching from the primary channel to at least one subchannel during the time period; transmitting or receiving data on the subchannel; and switching the operating channel to the primary channel.

[0012] According to one embodiment of the present disclosure, a method for operation of a station (STA) in a wireless LAN system includes the steps of detecting that a device other than an access point (AP) connected to the STA performs communication on a primary channel, the step of obtaining information related to a time period during which the communication is performed, the step of performing operation channel switching from the primary channel to at least one subchannel during the time period, the step of transmitting or receiving data on the subchannel, and the step of switching the operation channel to the primary channel.

[0013] According to one embodiment of the present disclosure, in a wireless LAN system, an access point (AP) includes a transceiver and a processor connected to the transceiver, wherein the processor is configured to detect that a device other than an STA connected to the AP performs communication on a primary channel, obtain information related to a time period during which the communication is performed, perform an operation channel switching from the primary channel to at least one subchannel during the time period, transmit or receive data on the subchannel, and switch the operation channel to the primary channel.

[0014] According to one embodiment of the present disclosure, in a wireless LAN system, a STA (station) includes a transceiver and a processor connected to the transceiver, wherein the processor is configured to detect whether a device other than an access point (AP) connected to the STA performs communication on a primary channel, obtain information related to a time period during which the communication is performed, perform an operation channel switching from the primary channel to at least one subchannel during the time period, transmit or receive data on the subchannel, and switch the operation channel to the primary channel.

[0015] According to the present disclosure, when a primary channel is busy in a wireless LAN system, communication can be performed on a subchannel.

[0016] According to the present disclosure, communication can be performed in a subchannel based on the magnitude of energy detected in a main channel in a wireless LAN system.

[0017] According to the present disclosure, communication using subchannels can be efficiently performed in a wireless LAN system.

[0018] The effects that can be obtained from the embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the technical configuration of the present disclosure is applied, from the description of the embodiments of the present disclosure below. In other words, unintended effects resulting from implementing the configuration described in the present disclosure can also be derived from the embodiments of the present disclosure by those skilled in the art.

[0019] Figure 1 is a block diagram illustrating a first embodiment of a communication node constituting a wireless LAN system.

[0020] Figure 2 illustrates a first embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0021] Figure 3 illustrates a second embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0022] Figure 4 illustrates a third embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0023] Figure 5 illustrates a fourth embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0024] Figure 6 illustrates a fifth embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0025] Figure 7 illustrates a sixth embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0026] FIG. 8 illustrates a flowchart of a procedure in which a STA (station) performs communication using a subchannel according to one embodiment of the present disclosure.

[0027] FIG. 9 illustrates a flowchart of a procedure in which an access point (AP) performs communication using a subchannel according to one embodiment of the present disclosure.

[0028] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0029] While terms such as "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a "second component," and similarly, a second component may also be referred to as a "first component." The term "and / or" includes a combination of multiple related items described herein or any of multiple related items described herein.

[0030] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0031] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0032] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0033] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate an overall understanding in describing the present invention, identical reference numerals are used for identical components in the drawings, and redundant descriptions of identical components are omitted.

[0034] Below, a wireless communication system to which embodiments of the present invention are applied will be described. The wireless communication system to which embodiments of the present invention are applied is not limited to the descriptions below, and embodiments of the present invention can be applied to various wireless communication systems. The wireless communication system may be referred to as a "wireless communication network."

[0035] Figure 1 is a block diagram illustrating a first embodiment of a communication node constituting a wireless LAN system.

[0036] Referring to FIG. 1, a communication node (100) may be an access point, a station, an access point (AP), a multi-link device (MLD), or a non-AP MLD. An access point may refer to an AP, and a station may refer to an STA or a non-AP STA. The operating channel width supported by the access point may be 20 MHz (megahertz), 80 MHz, 160 MHz, etc. The operating channel width supported by the station may be 20 MHz, 80 MHz, etc.

[0037] A communication node (100) may include at least one processor (110), a memory (120), and at least one transceiver (130) that is connected to a network and performs communication. The transceiver (130) may be referred to as a transceiver, an RF (radio frequency) unit, an RF module, etc. In addition, the communication node (100) may further include an input interface device (140), an output interface device (150), a storage device (160), etc. Each component included in the communication node (100) may be connected by a bus (170) and communicate with each other.

[0038] However, each component included in the communication node (100) may be connected through an individual interface or individual bus centered around the processor (110), rather than a common bus (170). For example, the processor (110) may be connected to at least one of a memory (120), a transmission / reception device (130), an input interface device (140), an output interface device (150), and a storage device (160) through a dedicated interface.

[0039] The processor (110) can execute program commands stored in at least one of the memory (120) and the storage device (160). The processor (110) may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor in which methods according to embodiments of the present invention are performed. Each of the memory (120) and the storage device (160) may be configured with at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory (120) may be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0040]

[0041] Hereinafter, embodiments of methods for wireless LAN devices to perform communication using subchannels are described with reference to drawings. The wireless LAN devices include an access point (AP) and a station (STA). The wireless LAN devices may be referred to as wireless LAN terminals. Alternatively, a wireless LAN terminal may refer to wireless LAN devices other than the AP. The wireless LAN devices may perform communication using a subchannel when communication cannot be performed on a primary channel. For example, if other devices communicate on the primary channel, interference may occur in the communication of the wireless LAN devices. According to one embodiment of the present disclosure, communication can be performed using a subchannel even when other devices communicate on the primary channel. The bandwidths of the primary channel and the subchannel may be the same. Alternatively, the bandwidths of the primary channel and the subchannel may be different. To perform communication, the AP and the STA may detect whether another device is communicating on the primary channel. Hereinafter, the subchannel may be referred to as an auxiliary primary channel or an auxiliary channel.

[0042]

[0043] Figure 2 illustrates a first embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0044] Referring to FIG. 2, wireless LAN terminals may operate in a wireless LAN channel (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz (or 80+80 MHz), 320 MHz channel). The wireless LAN terminal may include AP 1 and STA 1 associated with AP 1. Multiple wireless LAN terminals may further be associated with AP 1. Communication may be performed between AP 1 and the wireless LAN terminals associated with AP 1 using the wireless LAN channel. Communication by wireless LAN terminals other than AP 1 and the wireless LAN terminals associated with AP 1 may be referred to as OBSS (Overlapping Basic Service Set) communication. OBSS communication may cause interference to AP 1 and the wireless LAN terminals associated with AP 1.

[0045] In a wireless LAN channel, a primary channel (200) and a subchannel (210) may be set. The primary channel (200) and the subchannel (210) may be set or negotiated between AP 1 and a wireless LAN terminal connected to AP 1. The primary channel (200) may be a channel including a primary 20MHz channel. The subchannel (210) may be a channel not including a primary 20MHz channel. There may be at least one subchannel (210). For example, the wireless LAN channel may be 40MHz, the primary 20MHz channel may be the primary channel (200), and a non-primary 20MHz channel may be the subchannel (210). As another example, the wireless LAN channel may be 80MHz, the primary channel (200) may be a 40MHz channel including the primary 20MHz channel, and the remaining 40MHz channel may be the subchannel (210). Alternatively, the primary 20MHz channel may be the primary channel (200), and each of the 20MHz channels other than the primary channel (200) may be three subchannels (210). That is, the configuration of the primary channel (200) and the subchannels (210) may be configured in various forms. The subchannel (210) may also be referred to as an 'auxiliary primary channel', an 'auxiliary channel', or an 'alternative channel'. For example, in an 80MHz channel consisting of one primary channel (200) and three subchannels (210) as in the example above, the three subchannels (210) may be referred to as three auxiliary primary channels.

[0046] FIG. 2 is an embodiment for a case where there is one main channel (200) and one sub-channel (210). However, this embodiment is not intended to limit the operation to a case where there is only one main channel (200) and one sub-channel (210), and it should be understood that a wireless LAN terminal can operate in the same or similar manner as the embodiment even under various configurations of main channels (200) and sub-channels (210).

[0047] AP 1 and STA 1 can perform channel detection and / or channel access operations (e.g., EDCA backoff operation or backoff operation) on the primary channel (200). AP 1 can detect and decode frames transmitted from the OBSS on the primary channel (200) and recognize a communication section of the OBSS. For example, the frames transmitted from the OBSS include at least one of an RTS frame (220) or a data frame. The communication section of the OBSS can be recognized by information in a duration field present in the MAC header of the RTS frame (220) or / and information included in a PHY preamble of the RTS frame (220) (e.g., L-SIG information, etc.). When detecting a communication section by receiving and decoding a frame transmitted from the OBSS, a Basic NAV (Network Allocation Vector) that does not transmit during the corresponding section is set. Alternatively, AP 1 and STA 1 must receive a CTS frame after receiving an RTS frame of the OBSS in order to set a Basic NAV based on communication of the OBSS. Alternatively, AP 1 and STA 1 must receive a physical layer preamble within the NAVTimeout time after receiving the CTS frame of the OBSS to confirm the Basic NAV. If AP 1 and STA 1 do not receive an RTS frame after receiving the CTS frame of the OBSS or do not receive a physical layer preamble within the NAVTimeout time, the Basic NAV set by the RTS frame of the OBSS may be canceled. Since AP 1 has received the RTS frame of the OBSS, it may wait until it receives a CTS frame or a PHY preamble of the OBSS transmitted thereafter. If AP 1 receives the CTS frame or the PHY preamble of the OBSS, AP 1 may move to a subchannel and operate.That is, AP 1 may not operate on the subchannel immediately upon receiving the RTS frame of the OBSS, but may operate on the subchannel when the Basic NAV is confirmed. The Basic NAV may be confirmed when the CTS frame of the OBSS is received, or when the BSS Color, TXOP field, and Length field present in the PHY preamble of the frame of the OBSS are decoded, or when at least one MPDU is normally decoded after receiving the data frame of the OBSS, in which case AP 1 and STA 1 may operate on the subchannel. AP 1 may operate on the subchannel (210) during the communication section of the OBSS. The communication section of the OBSS is referred to as a 'subchannel communication possible section' or a 'communication possible section'. However, due to a difference in communication range or a channel condition, STA 1 may not receive the frame transmitted from the OBSS. That is, STA 1 may not be able to decode the frame transmitted from the OBSS. STA 1 can detect the energy of a frame transmitted from the OBSS. That is, STA 1 can detect that there is a frame transmission from the OBSS. An energy threshold for switching to a subchannel (210) may be set in STA 1. The energy threshold may be a preset value, a value broadcast by AP 1 through a beacon, etc., or a value negotiated between STA 1 and AP 1. If the energy of the RTS frame of the OBSS detected by STA 1 is equal to or greater than the energy threshold, STA 1 may operate in the subchannel (210). In the subchannel (210), AP 1 and STA 1 may perform a channel access operation. For example, AP 1 may perform an EDCA backoff operation in the subchannel (210). If the channel access operation of AP 1 is successful, AP 1 can transmit a downlink frame (230) to STA 1 in the subchannel, and STA 1 can transmit a response frame (e.g., a BlockAck (BA) frame) to AP 1.Alternatively, if the channel access operation of STA 1 is successful, STA 1 may transmit an uplink frame to AP 1. STA 1 may not know the communication section of the OBSS from the frame transmitted from the OBSS. If STA 1 does not know the communication section of the OBSS, STA 1 may transmit an RTS frame to AP 1. A specific value (for example, a duration field set to 0) may be indicated in the MAC header of the RTS frame. The RTS frame with the specific value set may indicate a 'request for communication section information'. AP 1 may receive the RTS frame with the specific value set and transmit a CTS frame to STA 1. AP 1 may indicate communication section information through the MAC header (for example, a duration field) of the CTS frame. STA 1 may transmit an uplink frame to AP 1 within the communication section. If AP 1 does not know the communication possible section information, it can transmit the CTS frame by setting a specific value (for example, the duration field set to 0) in the MAC header. If it does not know the communication possible section information, STA 1 does not transmit a data frame and ends the communication on the subchannel (210). After receiving the CTS frame, STA 1 immediately switches its operation to the main channel (200). AP 1 and all other STAs that receive the RTS frame and / or CTS frame and realize that they do not know the communication possible section information also immediately switch their operation to the main channel (200).

[0048] Alternatively, STA 1 may decode the frame transmitted from the OBSS, and AP 1 may not have decoded the frame transmitted from the OBSS. If the energy of the frame transmitted from the OBSS detected by AP 1 is greater than or equal to an energy threshold, AP 1 may operate in the subchannel (210). AP 1 may not know the communication section information of the OBSS and may transmit an RTS frame in which the specific value is set to STA 1 to STA 1. AP 1 may receive the RTS frame in which the specific value is set and transmit a CTS frame indicating the communication possible section to AP 1. AP 1 may transmit a downlink frame to STA 1 within the communication possible section. In the subchannel (210), the communication between AP 1 and STA 1 may be terminated within the communication section of the OBSS.

[0049] If STA 1 does not know the communication possible section information, STA 1 can transmit the CTS frame by setting a specific value (for example, the duration field set to 0) in the MAC header. If AP 1 does not know the communication possible section information, AP 1 does not transmit the data frame and ends the communication on the subchannel (210). After receiving the CTS frame, AP 1 immediately switches the operation to the main channel (200). All STAs that receive the RTS frame and / or CTS frame and realize that they do not know the communication possible section information also immediately switch the operation to the main channel (200).

[0050] In the subchannel (210), frame transmission and reception must be performed within the communication section of the OBSS. The frame transmission and reception end time in the subchannel (210) must take into account the transition delay to the main channel (200). Frame transmission and reception in the subchannel (210) must be completed before the channel transition time, and the AP and all STAs must switch to the main channel. Before the communication section of the OBSS ends, AP 1 and all STAs associated with AP 1 move to the main channel (200) and can communicate on the main channel (200) from the time when the communication section of the OBSS ends. The communication possible section information may be indicated by considering at least one of the communication section of the OBSS or the transition time to the main channel. The communication section of the OBSS may be the transmission time length of a TXOP or one PPDU of the OBSS.

[0051]

[0052] Figure 3 illustrates a second embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0053] Referring to FIG. 3, wireless LAN terminals may operate in a wireless LAN channel (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz (or 80+80 MHz), 320 MHz channel). The wireless LAN terminal may include AP 1 and STA 1 associated with AP 1. Multiple wireless LAN terminals may be further associated with AP 1. Communication may be performed between AP 1 and the wireless LAN terminals associated with AP 1 using the wireless LAN channel. Communication by wireless LAN terminals other than AP 1 and the wireless LAN terminals associated with AP 1 may be referred to as OBSS (Overlapping Basic Service Set) communication. OBSS communication may cause interference to AP 1 and the wireless LAN terminals associated with AP 1.

[0054] In a wireless LAN channel, a primary channel (300) and a subchannel (310) may be set. The primary channel (300) and the subchannel (310) may be set or negotiated between AP 1 and a wireless LAN terminal connected to AP 1. The primary channel (300) may be a channel including a primary 20MHz channel. The subchannel (310) may be a channel not including a primary 20MHz channel. There may be at least one subchannel (310). For example, the wireless LAN channel may be 40MHz, the primary 20MHz channel may be the primary channel (300), and a non-primary 20MHz channel may be the subchannel (310). As another example, the wireless LAN channel may be 80MHz, the primary channel (300) may be a 40MHz channel including the primary 20MHz channel, and the remaining 40MHz channel may be the subchannel (310). Alternatively, the primary 20MHz channel may be the primary channel (300), and each of the 20MHz channels other than the primary channel (300) may be three subchannels (310). That is, the configuration of the primary channel (300) and the subchannels (310) may be configured in various forms. The subchannels (310) may also be referred to as an 'auxiliary primary channel', an 'auxiliary channel', or an 'alternative channel'. For example, in an 80MHz channel composed of one primary channel (300) and three subchannels (310) as in the example above, the three subchannels (310) may be referred to as three auxiliary primary channels. The subchannels (310) may be referred to as subchannels (310).

[0055] FIG. 3 is an embodiment for a case where there is one main channel (300) and one sub-channel (310). However, this embodiment is not intended to limit the operation to a case where there is only one main channel (300) and one sub-channel (310), and it should be understood that a wireless LAN terminal can operate in the same or similar manner as the embodiment even under various configurations of main channels (300) and sub-channels (310).

[0056] AP 1 and STA 1 can perform channel detection and / or channel access operations (e.g., EDCA backoff operation or backoff operation) on the main channel (300). AP 1 can detect and decode the RTS frame (320) of the OBSS on the main channel (300) and know the communication section of the OBSS. The communication section of the OBSS can be known by information of the duration field present in the MAC header of the RTS frame (320) or / and information included in the PHY preamble of the RTS frame (320) (e.g., L-SIG information, etc.). AP 1 can operate on the subchannel (310) during the communication section of the OBSS. The communication section of the OBSS is referred to as a 'subchannel (310) communication possible section' or a 'communication possible section'. However, depending on the communication possible range or channel status, STA 1 may not detect and decode the RTS frame (320) of the OBSS. STA 1 can detect the energy of the CTS frame (330) of the OBSS or decode the CTS frame (330). If the energy of the CTS frame (330) of the OBSS detected by STA 1 is greater than the energy threshold set in STA 1, STA 1 can perform communication on the subchannel (310). Alternatively, if STA 1 decodes the RTS frame (320), the communication section of the OBSS can be known, and STA 1 can perform communication during the communication section of the OBSS on the subchannel (310). Due to the difference in the reception times of the RTS frame (320) and the CTS frame (330), the times at which AP 1 and STA 1 operate on the subchannel (310) may be different. For example, if AP 1 receives an RTS frame (320) of OBSS and transmits the frame to STA 1 on the subchannel (310) before the decoding completion or detection time of the CTS frame (330) on the subchannel (310), STA 1 cannot receive the frame.Accordingly, when AP 1 decodes the RTS frame (320) and moves to the subchannel (310), it may delay frame transmission on the main channel (300) until the time of completion of transmission of the CTS frame (330). For example, the channel access operation (e.g., EDCA backoff operation) of AP 1 may be repeated until the time of completion of transmission of the CTS frame (330). Alternatively, even when the channel access operation of AP 1 is successful (e.g., the EDCA backoff counter reaches 0), AP 1 may maintain the backoff counter at 0 until the time of completion of transmission of the CTS frame (330). AP 1 may transmit the downlink frame (340) to STA 1 after the time of completion of transmission of the CTS frame (330). AP 1 may transmit the downlink frame (340) to STA 1 in accordance with the time of completion of transmission of the CTS frame (330). Alternatively, AP 1 may transmit a downlink frame (340) to STA 1 at the time of initiating transmission of a data frame (350) after the SIFS time has elapsed after the completion of transmission of the CTS frame (330). STA 1, which has received the downlink frame (340), may transmit a response frame (e.g., a BlockAck (BA) frame) to AP 1. In the subchannel (310), communication between AP 1 and STA 1 may be terminated within the communication section of the OBSS. In addition to the difference in reception times of the RTS frame and the CTS frame, the frame reception times of AP 1 and STA 1 may be different from each other. For example, AP 1 may have received the CTS frame of the OBSS, but STA 1 may not have received the CTS frame of the OBSS. In contrast, STA 1 may not be aware of the TXOP section of the OBSS until the PHY preamble (e.g., L-SIG information, TXOP field, BSS Color information) or MAC header of the data frame of the OBSS transmitted after the CTS frame is decoded.In this case, AP 1 may not transmit frames on subchannels until STA 1 confirms the TXOP section of the OBSS. In other words, AP 1 may delay frame transmission until STA 1 confirms the communication section of the OBSS and operates on the subchannel.

[0057]

[0058] Figure 4 illustrates a third embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0059] Referring to FIG. 4, wireless LAN terminals may operate in a wireless LAN channel (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz (or 80+80 MHz), 320 MHz channel). The wireless LAN terminal may include AP 1 and STA 1 associated with AP 1. Multiple wireless LAN terminals may be further associated with AP 1. Communication may be performed between AP 1 and the wireless LAN terminals associated with AP 1 using the wireless LAN channel. Communication by wireless LAN terminals other than AP 1 and the wireless LAN terminals associated with AP 1 may be referred to as OBSS (Overlapping Basic Service Set) communication. OBSS communication may cause interference to AP 1 and the wireless LAN terminals associated with AP 1.

[0060] In a wireless LAN channel, a primary channel (400) and a subchannel (410) may be set. The primary channel (400) and the subchannel (410) may be set or negotiated between AP 1 and a wireless LAN terminal connected to AP 1. The primary channel (400) may be a channel including a primary 20MHz channel. The subchannel (410) may be a channel not including a primary 20MHz channel. There may be one or more subchannels (410). For example, the wireless LAN channel may be 40MHz, the primary 20MHz channel may be the primary channel (400), and a non-primary 20MHz channel may be the subchannel (410). As another example, the wireless LAN channel may be 80MHz, the primary channel (400) may be a 40MHz channel including a primary 20MHz channel, and the remaining 40MHz channels may be subchannels (410). Alternatively, the primary 20MHz channel may be the primary channel (400), and each of the 20MHz channels other than the primary channel (400) may be three subchannels (410). That is, the configuration of the primary channel (400) and the subchannels (410) may be configured in various forms. The subchannel (410) may also be referred to as an 'auxiliary primary channel', an 'auxiliary channel', or an 'alternative channel'. For example, in an 80MHz channel composed of one primary channel (400) and three subchannels (410) as in the example above, the three subchannels (410) may be referred to as three auxiliary primary channels. The subchannels (410) may be referred to as subchannels (410).

[0061] FIG. 4 is an embodiment for a case where there is one main channel (400) and one sub-channel (410). However, this embodiment is not intended to limit the operation to a case where there is only one main channel (400) and one sub-channel (410), and it should be understood that a wireless LAN terminal can operate in the same or similar manner as the embodiment even under various configurations of main channels (400) and sub-channels (410).

[0062] AP 1 and STA 1 can perform channel sensing and / or channel access operations (e.g., EDCA backoff operation or backoff operation) on the primary channel (400). STA 1 can sense and / or decode an RTS frame (420) of an OBSS on the primary channel (400). STA 1 can decode the RTS frame (420) or operate on a subchannel (410) when the energy of the RTS frame (420) is greater than or equal to an energy threshold. STA 1 can operate on a subchannel based on reception of an RTS frame of an OBSS, a CTS frame of an OBSS, and a data frame of an OBSS. For example, STA 1 may operate on a subchannel based on reception of a PHY preamble (e.g., L-SIG information, TXOP field, BSS Color information) of a data frame and / or a MAC header. STA 1 may perform a channel sensing / channel access operation on the subchannel (410). If there is no transmission from AP 1 or STAs connected to AP 1 for a certain period of time, STA 1 may operate on the main channel (400) again. The certain period value may be a preset value, a value broadcast by AP 1 through a beacon, etc., or a value negotiated by STA 1 and AP 1. Alternatively, if STA 1 succeeds in a channel access operation (EDCA backoff operation) on the subchannel (410), it may transmit an RTS frame to AP 1. AP 1 may not respond to STA 1. If AP 1 does not respond to STA 1's RTS frame, STA 1 can operate on the primary channel (400) again.

[0063] If STA 1 fails to decode the RTS frame (400), CTS frame, or data frame of the OBSS in the main channel (400) and the detected energy is below the energy threshold, STA 1 may not operate in the subchannel (410) and may continue to operate in the main channel (400).

[0064]

[0065] Figure 5 illustrates a fourth embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0066] Referring to FIG. 5, wireless LAN terminals may operate in a wireless LAN channel (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz (or 80+80 MHz), 320 MHz channel). The wireless LAN terminal may include AP 1 and STA 1 associated with AP 1. Multiple wireless LAN terminals may be further associated with AP 1. Communication may be performed between AP 1 and the wireless LAN terminals associated with AP 1 using the wireless LAN channel. Communication by wireless LAN terminals other than AP 1 and the wireless LAN terminals associated with AP 1 may be referred to as OBSS (Overlapping Basic Service Set) communication. OBSS communication may cause interference to AP 1 and the wireless LAN terminals associated with AP 1.

[0067] In a wireless LAN channel, a primary channel (500) and subchannels (511, 513, 515) may be set. The primary channel (500) and subchannels (511, 513, 515) may be set or negotiated between AP 1 and a wireless LAN terminal connected to AP 1. The primary channel (500) may be a channel including a primary 20MHz channel. The subchannels (511, 513, 515) may be channels that do not include a primary 20MHz channel. At least one subchannel (511, 513, 515) may exist. For example, the wireless LAN channel may be 40MHz, the primary 20MHz channel may be the primary channel, and the non-primary 20MHz channel may be the subchannel. As another example, a wireless LAN channel may be 80 MHz, the primary channel may be a 40 MHz channel including a primary 20 MHz channel, and the remaining 40 MHz channels may be subchannels. Alternatively, the primary 20 MHz channel may be the primary channel, and each of the 20 MHz channels other than the primary channel may be three subchannels. In other words, the configuration of the primary channel and subchannels may be configured in various forms. The subchannels (511, 513, 515) may also be referred to as an 'auxiliary primary channel', an 'auxiliary channel', or an 'alternative channel'. For example, in an 80 MHz channel consisting of one primary channel (500) and three subchannels (511, 513, 515) as in the example above, the three subchannels (511, 513, 515) may be referred to as three auxiliary primary channels.

[0068] FIG. 5 illustrates an embodiment for a case in which there is one main channel (500) and three subchannels (511, 513, 515). However, this embodiment is not intended to limit operation to a case in which there is only one main channel and three subchannels, and it should be understood that a wireless LAN terminal can operate in the same or similar manner as the embodiment even under various configurations of main channels and subchannels.

[0069] AP 1 and STA 1 can perform channel detection and / or channel access operations (e.g., EDCA backoff operation or backoff operation) on the primary channel (500). AP 1 can detect and decode an RTS frame of an OBSS on the primary channel (500) and recognize a communication section of the OBSS. The communication section of the OBSS can be recognized by information in a duration field present in a MAC header of the RTS frame or / and information included in a PHY preamble of the RTS frame (e.g., L-SIG information, etc.). In contrast, the communication section of the OBSS recognized from the RTS frame can be confirmed only by receiving a CTS frame transmitted subsequent to the RTS frame. The communication section of the OBSS can be confirmed by reception of a CTS frame, a PHY preamble (e.g., L-SIG information, TXOP field, BSS Color information), or a MAC header in addition to the RTS frame. Here, the PHY preamble and MAC header may be included in the data frame of the OBSS. AP 1 may operate on subchannels (511, 513, 515) during the communication period of the OBSS. The communication period of the OBSS is referred to as a 'subchannel communication possible period' or a 'communication possible period'. STA 1 may also decode the RTS frame in the same manner as AP 1. Alternatively, STA 1 may detect the energy of the RTS frame, and the detected energy may be greater than or equal to an energy threshold. Accordingly, STA 1 may operate on subchannels (511, 513, 515). AP 1 and STA 1 may have negotiated a procedure to operate in the order of subchannel 1 (511), subchannel 2 (513), and subchannel 3 (515) when the main channel (500) is being used by the OBSS. The subchannel number can be a sequential 20MHz channel extending from the main channel, such as 40MHz, 80MHz, etc. According to the negotiated procedure, AP 1 and STA 1 can operate on subchannel 1 (511).However, subchannel 1 (511) may be busy. Subchannel 1 (511) may be busy due to OBSS or due to non-802.11 (non-wireless LAN) communication. If subchannel 1 (511) is busy for a certain period of time, AP 1 and STA 1 may operate in subchannel 2 (513). For example, the certain period of time may be PIFS (priority interframe space). AP 1 and STA 1 may not know the communication section of subchannel 1 (511) and may communicate for the communication possible section confirmed in the primary channel (500). If AP 1 or STA 1 does not know the communication possible section, it may obtain communication possible section information through an RTS frame and CTS frame exchange procedure in which a specific value is set as or similar to the embodiment of FIG. 3. Subchannel 3 (515), which is an adjacent subchannel to subchannel 2 (513), can be used for communication together with subchannel 2 (513) when the channel is idle for a certain period of time (e.g., PIFS (priority interframe space) time).

[0070]

[0071] Figure 6 illustrates a fifth embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0072] Referring to FIG. 6, wireless LAN terminals may operate in a wireless LAN channel (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz (or 80+80 MHz), 320 MHz channel). The wireless LAN terminal may include AP 1 and STA 1 associated with AP 1. Multiple wireless LAN terminals may be further associated with AP 1. Communication may be performed between AP 1 and the wireless LAN terminals associated with AP 1 using the wireless LAN channel. Communication by wireless LAN terminals other than AP 1 and the wireless LAN terminals associated with AP 1 may be referred to as OBSS (Overlapping Basic Service Set) communication. OBSS communication may cause interference to AP 1 and the wireless LAN terminals associated with AP 1.

[0073] In a wireless LAN channel, a primary channel and a subchannel may be set. The primary channel and the subchannel may be set or negotiated between AP 1 and a wireless LAN terminal connected to AP 1. The primary channel may be a channel including a primary 20MHz channel. The subchannel may be a channel not including the primary 20MHz channel. There may be at least one subchannel. For example, the wireless LAN channel may be 40MHz, the primary 20MHz channel may be the primary channel, and a non-primary 20MHz channel may be the subchannel. As another example, the wireless LAN channel may be 80MHz, the primary channel may be a 40MHz channel including the primary 20MHz channel, and the remaining 40MHz channels may be subchannels. Alternatively, the primary 20MHz channel may be the primary channel (600), and each of the 20MHz channels other than the primary channel (600) may be three subchannels (611, 613, 615). That is, the configuration of the primary channel and subchannels can be configured in various forms. The subchannels may also be referred to as 'auxiliary primary channel', 'auxiliary channel', 'secondary channel', or 'alternative channel'. For example, in an 80 MHz channel consisting of one primary channel (600) and three subchannels (611, 613, 615) as in the above example, the three subchannels (611, 613, 615) can be referred to as three auxiliary primary channels.

[0074] FIG. 6 is an embodiment for a case where there is one main channel (600) and three sub-channels (611, 613, 615). However, this embodiment is not intended to limit the operation to a case where there is only one main channel (600) and three sub-channels (611, 613, 615), and it should be understood that a wireless LAN terminal can operate in the same or similar manner as the embodiment even under various configurations of main channels and sub-channels.

[0075] In AP 1 and STA 1, the channel access parameters of the main channel (600) and the subchannels (611, 613, 615) may be managed separately. For example, the channel access parameters of the main channel (600), CW[AC] and QSRC[AC], may be managed differently in the subchannels (611, 613, 615). The channel access parameters of the subchannels (611, 613, 615) may be managed as many times as the number of subchannels (611, 613, 615), or multiple subchannels (611, 613, 615) may use common channel access parameters. The channel access parameters of the main channel (600) and the channel access parameters of the subchannels (611, 613, 615) may or may not be linked. When the channel access parameters are not linked, the channel access parameters of the main channel (600) and subchannels (611, 613, 615) operate completely independently.

[0076] When channel access parameters are linked, for example, the following operations may be performed. If data related to a specific AC is successfully transmitted in a subchannel (611, 613, 615), EDCA parameters related to the corresponding AC may be initialized in the main channel (600). For example, CW[AC] and QSRC[AC] of the main channel (600) may be initialized. If data related to a specific AC is successfully transmitted in the main channel (600), EDCA parameters related to the corresponding AC may be initialized in the subchannel (611, 613, 615). For example, CW[AC] and QSRC[AC] of the subchannel (611, 613, 615) may be initialized.

[0077] If data related to a specific AC fails to be transmitted in a subchannel (611, 613, 615), an EDCA parameter related to the corresponding AC may be increased in the main channel (600). For example, CW[AC] and QSRC[AC] of the main channel (600) may be increased. If data related to a specific AC fails to be transmitted in the main channel, an EDCA parameter related to the corresponding AC may be increased in the subchannel (611, 613, 615). For example, CW[AC] and QSRC[AC] of the subchannel (611, 613, 615) may be increased. Even if the channel access parameters of the main channel (600) and the subchannel (611, 613, 615) are linked, some parameters may not be linked. For example, the QSRC[AC] parameter of the subchannels (611, 613, 615) may not be increased even if transmission fails on the main channel (600).

[0078] Alternatively, the channel access parameters of the subchannels (611, 613, 615) may be one-time. For example, when an AP and an STA that were operating on the main channel (600) move to and operate on the subchannels (611, 613, 615), the AP and the STA may select channel access parameters to use on the subchannels (611, 613, 615), and based on the selected channel access parameters, the AP and the STA may perform frame transmission on the subchannels (611, 613, 615). When the AP or STA moves from the subchannels (611, 613, 615) to the main channel (600) again, the channel access parameters of the subchannels (611, 613, 615) may be discarded regardless of the success or failure of transmission on the subchannels (611, 613, 615). The following is an example of the channel access parameter management method.

[0079] AP 1 and STA 1 can perform channel detection and / or channel access operations on the primary channel (600). For example, the channel access operation includes an EDCA backoff operation and a backoff operation (630). AP 1 can detect and decode an RTS frame (620) of an OBSS on the primary channel (600) and recognize a communication section of the OBSS. The communication section of the OBSS can be recognized by information in a duration field present in a MAC header of the RTS frame (620) or / and information included in a PHY preamble of the RTS frame (620) (e.g., L-SIG information, etc.). In contrast, the communication section of the OBSS recognized from the RTS frame can be confirmed only by receiving a CTS frame transmitted subsequent to the RTS frame. The communication section of the OBSS can be confirmed by reception of a CTS frame, a PHY preamble (e.g., L-SIG information, TXOP field, BSS Color information), or a MAC header in addition to the RTS frame. Here, the PHY preamble and the MAC header can be included in the data frame of the OBSS. AP 1 can operate in subchannels (611, 613, 615) during the communication section of the OBSS. The communication section of the OBSS is referred to as a 'subchannel communication possible section' or a 'communication possible section'. STA 1 can also decode the RTS frame (620) in the same way as AP 1. Alternatively, STA 1 can detect the energy of the RTS frame (620), and the detected energy may be equal to or higher than an energy threshold. Therefore, STA 1 can operate in subchannels (611, 613, 615). AP 1 and STA 1 may have negotiated a procedure to operate in the order of subchannel 1 (611), subchannel 2 (613), and subchannel 3 (615) when the primary channel (600) is in use by the OBSS.In at least one of subchannels 1 (611), 2 (613), and 3 (615), the transmission operation of AP 1 or / and STA 1 may have failed, and AP 1 and STA 1 may operate again on the primary channel (600). If the transmission in the subchannel (611, 613, 615) has failed, the channel access operation may be performed again on the primary channel (600). For example, the EDCA backoff counter (640) of AP 1 or / and STA 1 may reuse the backoff counter (630) used in the primary channel (600) before moving to the subchannel (611, 613, 615). Alternatively, the EDCA backoff counter (640) of AP 1 or / and STA 1 may be re-selected using the existing EDCA backoff parameters used in the primary channel (600), or may be re-selected using initialized EDCA backoff parameters (e.g., CW[AC] equal to CWmin[AC], QSRC[AC] equal to 0). Alternatively, for fairness in the event of a collision due to transmission failure in the subchannels (611, 613, 615), the backoff counter (640) of the primary channel (600) may be re-selected using increased EDCA backoff parameters (e.g., CW[AC] increased by a factor of 2 and QSRC[AC] increased by 1) compared to the EDCA parameters used in the primary channel (600).

[0080]

[0081] Figure 7 illustrates a sixth embodiment of a communication method using a subchannel of a wireless LAN terminal.

[0082] Referring to FIG. 7, wireless LAN terminals may operate in a wireless LAN channel (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz (or 80+80 MHz), 320 MHz channel). The wireless LAN terminal may include AP 1 and STA 1 associated with AP 1. Multiple wireless LAN terminals may be further associated with AP 1. Communication may be performed between AP 1 and the wireless LAN terminals associated with AP 1 using the wireless LAN channel. Communication by wireless LAN terminals other than AP 1 and the wireless LAN terminals associated with AP 1 may be referred to as OBSS (Overlapping Basic Service Set) communication. OBSS communication may cause interference to AP 1 and the wireless LAN terminals associated with AP 1.

[0083] In a wireless LAN channel, a primary channel and subchannels may be configured. The primary channel and subchannels may be configured or negotiated between AP 1 and a wireless LAN terminal connected to AP 1. The primary channel may be a channel including a primary 20MHz channel. The subchannel may be a channel not including the primary 20MHz channel. There may be at least one subchannel. For example, the wireless LAN channel may be 40MHz, the primary 20MHz channel may be the primary channel, and a non-primary 20MHz channel may be the subchannel. As another example, the wireless LAN channel may be 80MHz, the primary channel may be a 40MHz channel including the primary 20MHz channel, and the remaining 40MHz channels may be subchannels. Alternatively, the primary 20MHz channel may be the primary channel, and each of the non-primary 20MHz channels may be three subchannels. In other words, the configuration of the primary channel and subchannels may be configured in various forms. A subchannel may also be referred to as an 'auxiliary primary channel', an 'auxiliary channel', a 'secondary channel', or an 'alternative channel'. For example, in an 80 MHz channel consisting of one primary channel (700) and three subchannels (711, 713, 715) as in the example above, the three subchannels (711, 713, 715) may be referred to as three auxiliary primary channels.

[0084] Figure 7 illustrates an embodiment for a case where there is one main channel (700) and three sub-channels (711, 713, 715). However, this embodiment is not intended to limit the operation to a case where there is only one main channel (700) and three sub-channels (711, 713, 715), and it should be understood that a wireless LAN terminal can operate in the same or similar manner as the embodiment even under various configurations of main channels and sub-channels.

[0085] In AP 1 and STA 1, the channel access parameters of the main channel (700) and the subchannels (711, 713, 715) can be managed separately. Here, the channel access parameters include a backoff parameter. For example, the channel access parameters of the main channel (700), CW[AC] and QSRC[AC], can be managed differently in the subchannels (711, 713, 715). The channel access parameters of the subchannels (711, 713, 715) can be managed as many times as the number of subchannels (711, 713, 715), and multiple subchannels (711, 713, 715) can use common channel access parameters. The channel access parameters of the main channel (700) and the channel access parameters of the subchannels (711, 713, 715) may or may not be linked. When the channel access parameters are not linked, the channel access parameters of the main channel (700) and subchannels (711, 713, 715) operate completely independently.

[0086] When channel access parameters are linked, the following example may operate. If data related to a specific AC is successfully transmitted in a subchannel (711, 713, 715), EDCA parameters related to the corresponding AC may be initialized in the main channel (700). For example, CW[AC] and QSRC[AC] of the main channel (700) may be initialized. If data related to a specific AC is successfully transmitted in the main channel (700), EDCA parameters related to the corresponding AC may be initialized in the subchannels (711, 713, 715). For example, CW[AC] and QSRC[AC] of the subchannels (711, 713, 715) may be initialized.

[0087] If transmission of data related to a specific AC fails in a subchannel (711, 713, 715), an EDCA parameter related to the corresponding AC may be increased in the main channel (700). For example, CW[AC] and QSRC[AC] of the main channel (700) may be increased. If transmission of data related to a specific AC fails in the main channel (700), an EDCA parameter related to the corresponding AC may be increased in the subchannel (711, 713, 715). For example, CW[AC] and QSRC[AC] of the subchannel (711, 713, 715) may be increased. Even if the channel access parameters of the main channel (700) and the subchannels (711, 713, 715) are linked, some parameters may not be linked. For example, the QSRC[AC] parameter of the subchannels (711, 713, 715) may not be increased even if data transmission on the main channel (700) fails.

[0088] Alternatively, the channel access parameters of the subchannels (711, 713, 715) may be one-time. For example, when an AP and an STA that were operating on the main channel (700) move to operate on the subchannels (711, 713, 715), the AP and the STA may select channel access parameters to use on the subchannels (711, 713, 715) and perform frame transmission on the subchannels (711, 713, 715) based on the selected channel access parameters. When operating from the subchannels (711, 713, 715) back to the main channel (700), the AP and the STA may discard the channel access parameters of the subchannels (711, 713, 715) regardless of the success or failure of transmission on the subchannels (711, 713, 715). The following is an example of the channel access parameter management method.

[0089] AP 1 and STA 1 can perform channel detection and / or channel access operation (730) on the primary channel (700). For example, the channel access operation (730) includes at least one of an EDCA backoff operation or a backoff operation. AP 1 can detect and decode an RTS frame (720) of an OBSS on the primary channel (700) and recognize a communication section of the OBSS. The communication section of the OBSS can be recognized by information of a duration field present in a MAC header of the RTS frame (720) or / and information included in a PHY preamble of the RTS frame (720) (e.g., L-SIG information, etc.). In contrast, the communication section of the OBSS recognized from the RTS frame can be confirmed only by receiving a CTS frame transmitted subsequent to the RTS frame. The communication section of the OBSS can be confirmed by reception of a CTS frame, a PHY preamble (e.g., L-SIG information, TXOP field, BSS Color information), or a MAC header in addition to the RTS frame. Here, the PHY preamble and the MAC header can be included in the data frame of the OBSS. AP 1 can operate in subchannels (711, 713, 715) during the communication section of the OBSS. The communication section of the OBSS is referred to as a 'subchannel communication possible section' or a 'communication possible section'. STA 1 can also decode the RTS frame (720) in the same way as AP 1. Alternatively, STA 1 can detect the energy of the RTS frame (720), and the detected energy may be equal to or higher than an energy threshold. Therefore, STA 1 can operate in subchannels (711, 713, 715). AP 1 and STA 1 may have negotiated a procedure to operate in the order of subchannel 1 (711), subchannel 2 (713), and subchannel 3 (715) when the main channel (700) is in use by the OBSS.In at least one of subchannels 1 (711), 2 (713), and 3 (715), the transmission operation of AP 1 or / and STA 1 may have succeeded, and AP 1 and STA 1 may operate again in the primary channel (700). In the primary channel (700), a channel access operation (740) may be performed again. Since a frame has already been transmitted in the primary channel (700), a backoff counter (740) may be selected again in the primary channel (700) for fairness. The backoff counter (740) of AP 1 or / and STA 1 may be selected using the EDCA backoff parameter used in the primary channel (700) before moving to the subchannels (711, 713, 715). Alternatively, the backoff counter (740) of AP 1 or / and STA 1 may be newly selected using one of the increased EDCA backoff parameters (e.g., CW[AC] increased by 2 times and QSRC[AC] increased by 1) or the initialized EDCA backoff parameters (e.g., CW[AC] equal to CWmin[AC], QSRC[AC] equal to 0) compared to the EDCA backoff parameters used in the primary channel (700) of AP 1 or / and STA 1. Alternatively, if the backoff counter (730) used in the primary channel (700) of AP 1 or / and STA 1 is greater than a certain value, AP 1 or / and STA 1 may perform channel access without newly selecting the backoff counter (740) in the primary channel (700).

[0090]

[0091] Hereinafter, a communication method using a subchannel according to an embodiment of the present disclosure is exemplarily described. The communication method using a subchannel is performed by an AP and an STA. The STA may be an STA connected to the AP. When the primary channel is in use, the AP and the STA may perform communication using at least one subchannel. That is, when the primary channel is in use, the STA and the AP may perform communication by switching to a subchannel. In other words, the STA and the AP may temporarily use a subchannel as a primary channel. In other words, a subchannel may serve as an alternative or substitute for the primary channel. The operation of switching a channel to a subchannel may be referred to as subchannel connection, channel switching, subchannel switching, or channel switching. The operation of switching a channel from a subchannel to a primary channel may be referred to as channel reversion. The subchannel may be a channel in an adjacent band. The subchannel may refer to a channel in a band remaining from the entire channel band excluding the band of the primary channel.

[0092]

[0093] FIG. 8 illustrates an embodiment of a method for operating an STA according to an embodiment of the present disclosure. FIG. 8 illustrates an embodiment of a method for operating an STA associated with an AP. The STA can transmit or receive data.

[0094] Referring to FIG. 8, in step S801, the STA detects whether another device is performing communication. Here, the other device refers to a device other than the STA and an AP connected to the STA. The communication of the other device may be referred to as OBSS communication. The STA can detect whether OBSS communication is performed using a frame transmitted during OBSS communication. For example, the STA can recognize OBSS communication by detecting the energy of an RTS frame of OBSS communication (e.g., the RTS frame (320) of FIG. 3). As another example, the STA can recognize OBSS communication by detecting the energy of a CTS frame of OBSS communication (e.g., the CTS frame (330) of FIG. 3). As yet another example, the STA can recognize OBSS communication by decoding a frame of OBSS communication. The STA can obtain information regarding an OBSS communication section. The OBSS communication section refers to a time section during which OBSS communication is performed. Information about the communication section can be obtained from the AP. Alternatively, information about the OBSS communication section can be obtained based on a frame transmitted in the OBSS communication (e.g., the RTS frame (320) of FIG. 3). If information about the OBSS communication section cannot be obtained, the STA may not perform steps S803 and below.

[0095] In step S803, the STA switches the operating channel from the main channel (e.g., the main channel (300) of FIG. 3) to at least one subchannel (e.g., the subchannel (310) of FIG. 3). Here, the operating channel is a channel that the AP and the STA use for communication. The STA may switch the operating channel to a subchannel adjacent to the main channel. Here, the subchannel adjacent to the main channel means a subchannel whose frequency band is adjacent to the main channel. If the subchannel adjacent to the main channel is busy, the STA may switch the channel to another subchannel. For example, the STA may switch the channel to a subchannel (e.g., subchannel 2 (513) of FIG. 5) adjacent to a busy subchannel (e.g., subchannel 1 (511) of FIG. 5). The STA may switch the channel to at least one subchannel that is idle. In other words, the STA can switch the channel to at least one subchannel that includes a subchannel with a frequency band closest to the primary channel among the subchannels that are not in a busy state.

[0096] In step S805, the STA transmits or receives on a subchannel. The STA determines a transmission time point to perform transmission. The transmission time point may be, for example, a time point when both the STA and the AP switch the operating channel to the subchannel. The STA performs a channel access procedure to perform transmission. The channel access procedure may be, for example, an EDCAF backoff procedure. The channel access procedure of the subchannel may be performed based on at least one of a channel access parameter of the subchannel or a channel access parameter of the primary channel. The channel access parameter includes a backoff parameter. The channel access parameter of the subchannel may be linked to the channel access parameter of the primary channel. Alternatively, the channel access parameter of the subchannel and the channel access parameter of the primary channel may be independent. After the channel access procedure is successful, the STA may wait until the AP and the STA switch the channel to the subchannel, or may retry the channel access procedure. That is, after both the AP and the STA switch the channel to a subchannel, the STA can transmit data. To this end, the STA can anticipate the AP's channel switching time. For example, the STA can anticipate the AP's channel switching time. For example, the STA can anticipate the AP's channel switching time based on the time when the CTS frame transmission is completed. After the channel access procedure is successful, the STA transmits data to the AP. The data transmission may be successful. Alternatively, the data transmission may fail. If no frame is received from the AP for a specific period of time, the STA performs step S807. Here, the specific period of time may be defined by negotiation between the AP and the STA, broadcast by the AP, or may be a predefined value.

[0097] In step S807, the STA returns to the primary channel. In other words, the STA switches the channel from the subchannel to the primary channel. The STA switches the channel to the primary channel before the OBSS communication section ends. The STA may perform a channel access procedure (e.g., channel access procedure (640) of FIG. 6) for transmission on the primary channel. The channel access parameters of the primary channel and the channel access parameters of the subchannel may not be linked. Alternatively, the channel access parameters of the primary channel and the channel access parameters of the subchannel may be linked. For example, if data transmission on the subchannel is successful, the channel access parameters of the primary channel may change. The channel access parameters of the primary channel may have increased values, decreased values, or initialized values ​​compared to the channel access parameters previously used on the primary channel. As another example, if data transmission on the subchannel fails, the channel access parameters of the primary channel may change based on the channel access parameters of the subchannel. The channel access parameters of the primary channel may have values ​​that are increased, decreased, or initialized compared to the channel access parameters previously used in the primary channel.

[0098]

[0099] FIG. 9 illustrates an embodiment of an operation method of an AP according to an embodiment of the present disclosure. FIG. 9 illustrates an embodiment of a method for an AP associated with an AP to operate. The AP can transmit or receive data.

[0100] Referring to FIG. 9, in step S901, the AP detects whether another device is occupying the primary channel. Here, the other device refers to a device other than the AP and the STA connected to the AP. The other device occupying the primary channel may mean that the other device is performing communication on the primary channel. The communication of the other device may be referred to as OBSS communication. The AP can detect whether OBSS communication is performed using a frame transmitted during OBSS communication. For example, the AP can recognize OBSS communication by detecting the energy of an RTS frame of OBSS communication (e.g., an RTS frame (320) of FIG. 3). As another example, the AP can recognize OBSS communication by detecting the energy of a CTS frame of OBSS communication (e.g., a CTS frame (330) of FIG. 3). As yet another example, the AP can recognize OBSS communication by decoding a frame of OBSS communication. The AP can obtain information regarding an OBSS OBSS communication section. An OBSS communication interval refers to the time period during which OBSS communication is performed. Information about the OBSS communication interval can be obtained from the AP. Alternatively, information about the OBSS communication interval can be obtained based on frames transmitted during OBSS communication. If information about the OBSS communication interval cannot be obtained, the AP may not perform steps S903 and below.

[0101] In step S903, the AP switches the operating channel from the main channel (e.g., the main channel (300) of FIG. 3) to at least one subchannel (e.g., the subchannel (310) of FIG. 3). Here, the operating channel is a channel used by the AP and the STA for communication. The AP may switch the operating channel to a subchannel adjacent to the main channel. Here, the subchannel adjacent to the main channel means a subchannel whose frequency band is adjacent to the main channel. If the subchannel adjacent to the main channel is busy, the AP may switch the channel to another subchannel. For example, the AP may switch the channel to a subchannel adjacent to a busy subchannel (e.g., subchannel 1 (511) of FIG. 5) (e.g., subchannel 2 (513) of FIG. 5). The AP may switch the channel to at least one subchannel that is idle. In other words, the AP can switch the channel to at least one subchannel that includes a subchannel with a frequency band closest to the primary channel among the subchannels that are not in a busy state.

[0102] In step S905, the AP transmits or receives on a subchannel. To transmit, the AP determines a transmission time. The transmission time may be, for example, a time when both the STA and the AP switch their operating channels to the subchannel. To transmit, the AP performs a channel access procedure. The channel access procedure may be, for example, an EDCAF backoff procedure. The channel access procedure of the subchannel may be performed based on at least one of the channel access parameters of the subchannel or the channel access parameters of the primary channel. The channel access parameters include a backoff parameter. The channel access parameters of the subchannel may be linked to the channel access parameters of the primary channel. Alternatively, the channel access parameters of the subchannel and the channel access parameters of the primary channel may be independent. After the channel access procedure is successful, the AP may wait until the AP and the STA switch to the subchannel, or may retry the channel access procedure. In other words, the AP can transmit data after both the AP and the STA switch to the subchannel. To this end, the AP may anticipate the channel switching time of the STA. For example, the AP can anticipate the timing of a channel transition for an STA. For example, the AP can anticipate the timing of a channel transition for an STA based on the completion time of transmission of a CTS frame. After the channel access procedure is successful, the AP transmits data to the STA. The data transmission may succeed. Alternatively, the data transmission may fail. If no frame is received from the AP for a specific period of time, the AP performs step S907. Here, the specific period of time may be defined through negotiation between the AP and the STA, broadcast by the AP, or may be a predefined value.

[0103] In step S907, the AP returns the operating channel to the primary channel. In other words, the AP switches from the subchannel to the primary channel. The AP switches to the primary channel before the OBSS communication section ends. The AP may perform a channel access procedure (e.g., channel access procedure (640) of FIG. 6) for transmission on the primary channel. The channel access parameters of the primary channel and the channel access parameters of the subchannel may not be linked. Alternatively, the channel access parameters of the primary channel and the channel access parameters of the subchannel may be linked. For example, if data transmission on the subchannel is successful, the channel access parameters of the primary channel may change. The channel access parameters of the primary channel may have a value that is increased, decreased, or initialized compared to the channel access parameters previously used on the primary channel. As another example, if data transmission on the subchannel fails, the channel access parameters of the primary channel may change based on the channel access parameters of the subchannel. The channel access parameters of the primary channel may have values ​​that are increased, decreased, or initialized compared to the channel access parameters previously used in the primary channel.

[0104]

[0105] The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., either singly or in combination. The program instructions recorded on the computer-readable medium may be those specifically designed and constructed for the present invention, or may be known and available to those skilled in the computer software art.

[0106] Examples of computer-readable media include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include not only machine language codes generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc. The hardware devices described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

[0107] Although the present invention has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

[0108]

[0109] The present disclosure can be used in devices and recording media in a wireless LAN system.

Claims

1. A method for operating an AP (access point) in a wireless LAN system, A step of detecting that a device other than at least one STA (station) connected to the AP performs communication on the primary channel; A step of obtaining information related to the time period during which the above communication is performed; A step of switching the operating channel from the main channel to at least one subchannel during the time interval; A step of transmitting or receiving data in the above subchannel; A method comprising the step of switching the operating channel to the primary channel.

2. In paragraph 1, A method further comprising the step of determining a transmission point for transmission or reception of the data in the subchannel.

3. In paragraph 2, A method in which the above transmission time is determined based on whether the AP and the at least one STA switch to the operating channel.

4. In paragraph 2, A method in which the above transmission time is determined based on the time at which the at least one STA switches the operating channel.

5. In paragraph 2, The step of performing the above transmission or reception is: A method comprising the step of performing a channel access procedure for the transmission in the above subchannel.

6. In paragraph 4, A method in which the channel connection procedure is repeatedly performed until the transmission time, if the channel connection procedure is completed before the transmission time.

7. In paragraph 1, A method of performing the above communication, wherein the detection is based on the energy size of the frame used for the above communication.

8. In paragraph 1, A method in which information about the above time interval is obtained from the STA or by decoding a frame used for the communication.

9. In paragraph 1, A method wherein the step of switching the operating channel to the above primary channel is performed within the above time interval.

10. A method for operation of STA (station) in a wireless LAN system, A step for detecting that a device other than an access point (AP) connected to the STA is performing communication on the primary channel; A step of obtaining information related to the time period during which the above communication is performed; A step of performing an operation channel switching from the main channel to at least one subchannel during the time interval; A step of transmitting or receiving data in the above subchannel; A method comprising the step of switching the operating channel to the primary channel.

11. In clause 10, A method further comprising the step of determining a transmission point for transmitting or receiving the data in the subchannel.

12. In paragraph 11, A method in which the above transmission time is determined based on whether the STA and the AP switch to the above operation channel.

13. In paragraph 11, A method in which the above transmission time is determined based on the time at which the at least one STA switches the operating channel.

14. In paragraph 12, The step of performing the above transmission or reception is: A method comprising the step of performing a channel access procedure for the transmission in the above subchannel.

15. In paragraph 13, A method in which the channel connection procedure is repeatedly performed until the transmission time, if the channel connection procedure is completed before the transmission time.

16. In paragraph 10, A method of performing the above communication, wherein the detection is based on the energy size of the frame used for the above communication.

17. In paragraph 10, A method in which information about the above time interval is obtained from the AP or by decoding a frame used for the communication.

18. In paragraph 10, A method wherein the step of switching the operating channel to the above primary channel is performed within the above time interval.

19. In a wireless LAN system, at the AP (access point), Transmitter and receiver; and Including a processor connected to the above transceiver, The above processor, Detects that a device other than the STA (station) connected to the AP is performing communication on the primary channel, Obtain information related to the time period during which the above communication is performed, During the above time interval, the operating channel is switched from the main channel to at least one subchannel, Transmitting or receiving data on the above subchannel, An AP configured to switch the operating channel to the primary channel.

20. In a wireless LAN system, at STA (station), Transmitter and receiver; and Including a processor connected to the above transceiver, The above processor, Detects that a device other than the AP (access point) connected to the STA is performing communication on the primary channel, Obtain information related to the time period during which the above communication is performed, During the above time interval, the operating channel is switched from the main channel to at least one subchannel, Transmitting or receiving data on the above subchannel, An STA configured to switch the above-described operating channel to the above-described primary channel.

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