Method for transmitting and receiving data in a wireless communication system and wireless communication terminal - Patents.com

Abstract

A method for transmitting and receiving a TB PPDU based on a trigger frame in a wireless communication system is provided, wherein a terminal receives a trigger frame from an access point (AP) and transmits a response frame in response to the trigger frame, and the response frame may be generated based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields of the trigger frame according to a format and / or resource unit of the response frame.

Description

[Technical field]

[0001] The present invention relates to a wireless communication system, and more particularly, to a trigger frame for instructing transmission of a TB (Trigger Based) PPDU (Physical layer Protocol Data Unit) in a wireless communication system, and a method and apparatus for configuring, transmitting and receiving a TB PPDU based on the trigger frame. [Background technology]

[0002] Recently, as the use of mobile devices has become more widespread, wireless LAN technology that can provide them with high-speed wireless Internet services has been attracting attention. Wireless LAN technology is a technology that enables mobile devices such as smartphones, smart pads, laptop PCs, portable multimedia players, embedded devices, etc. to wirelessly connect to the Internet at home, in business, or in specific service areas based on short-distance wireless communication technology.

[0003] Since IEEE (Institute of Electronics Engineers) 802.11 supported the initial wireless LAN technology using the 2.4GHz frequency band, it has put into practical use or is currently developing various technology standards. First, IEEE 802.11b uses the 2.4GHz frequency band and supports a maximum communication speed of 11Mbps. IEEE 802.11a, which was commercialized after IEEE 802.11b, uses the 5GHz frequency band instead of the 2.4GHz band, reducing the impact of interference compared to the significantly more congested 2.4GHz frequency band, and uses OFDM technology to increase communication speeds to a maximum of 54Mbps. However, IEEE 802.11a has the disadvantage of a shorter communication distance than IEEE 802.11b. IEEE 802.11g, like IEEE 802.11b, uses the 2.4GHz band and achieves a maximum transmission speed of 54Mbps, and has attracted considerable attention because it satisfies backward compatibility, but it also has an advantage over IEEE 802.11a in communication distance.

[0004] IEEE 802.11n is a technical standard established to overcome the communication speed limitations that have been pointed out as a weakness of wireless LAN. The purpose of IEEE 802.11n is to increase the speed and reliability of the network and to extend the operating distance of the wireless network. In detail, IEEE 802.11n supports a high throughput (HT) of up to 540Mbps or more in data processing speed, and is based on MIMO (Multiple Inputs and Multiple Outputs) technology that uses multiple antennas on both the transmitting and receiving ends to minimize transmission errors and optimize data speed. This standard also uses a coding method that transmits multiple duplicate copies to increase data reliability.

[0005] As the use of wireless LANs becomes more widespread and applications using them become more diverse, the need for new wireless LAN systems to support data throughput rates (Very High Throughput, VHT) higher than those supported by IEEE 802.11n is emerging. Among them, IEEE 802.11ac supports wide bandwidth (80MHz~160MHz) at 5GHz frequency. Although the IEEE 802.11ac standard is defined only in the 5GHz band, it is expected that initial 11ac chipsets will also support operation in the 2.4GHz band for backward compatibility with existing 2.4GHz band products. Theoretically, this standard allows multi-station wireless LAN speeds of at least 1Gbps and maximum single link speeds of at least 500Mbps. This is done by extending the air interface concepts accepted by 802.11n, such as wider radio frequency bandwidth (up to 160MHz), more MIMO spatial streams (up to 8), multi-user MIMO, and high density modulation (up to 256QAM). Also, there is IEEE 802.11ad, a method of transmitting data using the 60GHz band instead of the conventional 24GHz / 5GHz. IEEE 802.11ad is a transmission standard that uses beamforming technology to provide speeds of up to 7Gbps, and is suitable for streaming large amounts of data and high bitrate videos such as uncompressed HD video. However, the 60GHz frequency band has the disadvantage that it is difficult to pass through obstacles and can only be used between devices in close proximity.

[0006] Meanwhile, the IEEE 802.11ax (High Efficiency WLAN, HEW) standard is being developed and is in the final stages as the WLAN standard after 802.11ac and 802.11ad to provide high-efficiency and high-performance WLAN communication technology in high-density environments where APs and terminals are densely packed. In an 802.11ax-based WLAN environment, it is necessary to provide high-frequency efficient communication indoors / outdoors in the presence of high density stations and APs (Access Points), and various technologies are being developed to realize this.

[0007] In addition, new WLAN standards have begun to be developed to increase maximum transmission speeds to support new multimedia applications such as high-definition video and real-time games. IEEE 802.11be (Extremely High Throughput, EHT), the 7th generation WLAN standard, is currently being developed with the goal of supporting transmission rates of up to 30Gbps in the 2.4 / 5 / 6GHz bands through wider bandwidth, increased spatial streams, and multiple AP cooperation. Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, an object of the present invention is to provide an ultra-high speed wireless LAN service for new multimedia applications.

[0009] Another object of the present invention is to provide a method and apparatus for configuring a trigger frame for instructing transmission of a TB PPDU, which is a PPDU based on a trigger frame, according to its type.

[0010] Another object of the present invention is to provide a method and apparatus for generating a High Efficiency (HE) PPDU or an Extremely High Throughput (EHT) PPDU according to different information included in a trigger frame transmitted from an Access Point (AP).

[0011] The technical problem to be achieved in this specification is not limited to the technical problem mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present invention pertains from the following description. [Means for solving the problem]

[0012] A terminal for transmitting a TB PPDU (Trigger Based Physical layer Protocol Data Unit), which is a response frame based on a trigger frame in a wireless communication system, includes a communication module; and a processor for controlling the communication module, the processor receives a trigger frame from an AP (Access Point), the trigger frame includes a common information field including a first plurality of spatial reuse fields, and identifies whether the trigger frame includes an additional information field including a second plurality of spatial reuse fields based on identification information of the trigger frame, and transmits a response frame generated based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields in response to the trigger frame, and whether the response frame is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields is determined based on a format associated with the trigger frame.

[0013] Also, in the present invention, when a format associated with the trigger frame is an Extremely High Throughput (EHT) format, the response frame is generated based on information obtained from the second plurality of spatial reuse fields.

[0014] Also, in the present invention, when a format associated with the trigger frame is a High Efficiency (HE) format, the response frame is generated based on information obtained from the first plurality of spatial reuse fields.

[0015] In addition, in the present invention, whether the response frame is generated based on information obtained from the first plurality of spatial reuse fields or based on information obtained from the second plurality of spatial reuse fields is determined based on a position on a frequency axis of a resource unit from which the response frame is transmitted.

[0016] In addition, in the present invention, the trigger frame further includes a bandwidth field, an additional bandwidth field, and a resource allocation field indicating a resource unit in which the response frame is transmitted.

[0017] In addition, in the present invention, the processor recognizes the resource unit from which the response frame is transmitted based on the resource allocation field, and generates a response frame based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields according to a position on a frequency axis of the resource unit from which the response frame is transmitted.

[0018] In addition, in the present invention, the trigger frame further includes a puncturing mode field indicating the presence or absence of puncturing and the punctured position in the bandwidth indicated by the bandwidth field and / or the additional bandwidth field.

[0019] Also, in the present invention, when the response frame is generated based on the second plurality of spatial reuse fields, the response frame is transmitted at a bandwidth indicated by a bandwidth field included in the common information field and an additional bandwidth field included in the additional information field.

[0020] Also, in the present invention, the response frame includes a plurality of spatial reuse fields, each of which is set based on information obtained from a corresponding one of the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

[0021] In addition, in the present invention, whether the trigger frame includes the additional information field is recognized based on whether the value of a specific subfield indicating whether the additional information field is included in the common information field and / or whether the value of an identifier of the additional information field is set to a specific value.

[0022] In addition, in the present invention, the response frame is a TB PPDU (Trigger based Physical layer Protocol Data Unit), and the TB PPDU is transmitted in the form of an A (aggregated)-PPDU by aggregation with at least one TB PPDU transmitted from at least one other terminal instructed to transmit a TB PPDU by the trigger frame, and the at least one TB PPDU is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields, and the TB PPDU and the at least one TB PPDU are generated based on different spatial reuse fields.

[0023] The present invention also provides a method, comprising: receiving a trigger frame from an Access Point (AP), the trigger frame including a common information field including a first plurality of spatial reuse fields, and identifying whether the trigger frame includes an additional information field including a second plurality of spatial reuse fields based on identification information of the trigger frame; and transmitting a response frame generated based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields in response to the trigger frame, the response frame being generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields, determined based on a format associated with the trigger frame. Effect of the Invention

[0024] According to an embodiment of the present invention, by using a trigger frame to transmit information for generating TB PPDUs of different formats in different fields, it is possible to instruct the transmission of TB PPDUs of multiple formats by a single signaling.

[0025] In addition, according to an embodiment of the present invention, information for spatial reuse for TB PPDUs of different formats is included in different fields of a trigger frame depending on each format and transmitted, thereby increasing the resolution of spatial reuse represented in the TB PPDU.

[0026] Furthermore, according to the embodiment of the present invention, the resolution of spatial reuse represented in the TB PPDU is increased, thereby improving the spatial reuse efficiency of an overlapping basic service set (OBSS).

[0027] Furthermore, according to the embodiment of the present invention, the trigger frame is transmitted on a discontinuous channel, thereby allowing multiple STAs to transmit the TB PPDU.

[0028] The effects obtained from the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a diagram showing a wireless LAN system according to an embodiment of the present invention. [Diagram 2] FIG. 11 is a diagram showing a wireless LAN system according to another embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram showing a configuration of a station according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing the configuration of an access point according to an embodiment of the present invention. [Diagram 5]1 is a diagram illustrating a process in which a STA sets up a link with an AP. [Figure 6] FIG. 1 is a diagram illustrating a CSMA (Carrier Sense Multiple Access) / CA (Collision Avoidance) method used in wireless LAN communication. [Figure 7] 1 shows a PPDU format for an extremely high throughput (EHT) wireless LAN according to an embodiment of the present invention. [Figure 8] 13 illustrates a U-SIG field of a TB PPDU according to one embodiment of the present invention. [Figure 9] 1 shows an example of a trigger format according to an embodiment of the present invention. [Figure 10] 1 shows an example of the configuration of a common information field of a trigger frame according to an embodiment of the present invention. [Figure 11] 13 shows an example of the configuration of an additional information field in the format of a trigger frame according to one embodiment of the present invention. [Figure 12] 1 illustrates an example of a spatial reuse field and a puncturing mode field for uplink transmission according to one embodiment of the present invention. [Figure 13] 1 shows an example of transmission of a trigger frame and a trigger frame-based TB PPDU according to an embodiment of the present invention. [Figure 14A] 13 illustrates yet another example of transmitting a trigger frame and a trigger frame-based TB PPDU according to an embodiment of the present invention. [Figure 14B] 13 illustrates yet another example of transmitting a trigger frame and a trigger frame-based TB PPDU according to an embodiment of the present invention. [Figure 15] 1 is a flowchart illustrating an example of a method for selecting a spatial reuse field for generating a TB PPDU based on a trigger frame according to an embodiment of the present invention. [Figure 16]13 illustrates an example of spatial reuse operation according to the number of spatial reuse fields for a frequency band according to an embodiment of the present invention. [Figure 17] 1 shows an example of a method for transmitting a trigger frame according to an embodiment of the present invention. [Figure 18] 1 illustrates an example of a TB PPDU including a puncturing mode according to an embodiment of the present invention. [Figure 19] 13 shows an example of a resource unit allocation procedure and a TB PPDU response procedure using a trigger frame according to an embodiment of the present invention. [Figure 20] 1 illustrates an example of a method for receiving a TB PPDU based on a trigger frame according to an embodiment of the present invention. [Figure 21] 13 illustrates yet another example of a method for receiving a TB PPDU based on a trigger frame according to an embodiment of the present invention. [Figure 22] 13 illustrates yet another example of a method for receiving a TB PPDU based on a trigger frame according to an embodiment of the present invention. [Figure 23] 13 illustrates yet another example of a method for receiving a TB PPDU based on a trigger frame according to an embodiment of the present invention. [Figure 24] 1 illustrates an example of a user information field of a trigger frame according to an embodiment of the present invention. [Diagram 25] 1 illustrates an example of a method for transmitting a TB PPDU based on a trigger frame according to an embodiment of the present invention. [Figure 26] 13 shows an example of a format of a U-SIG field of a TB PPDU according to one embodiment of the present invention. [Figure 27] 13 illustrates an example of a resource unit configuration and signaling for transmitting a TB PPDU according to an embodiment of the present invention. [Figure 28] 13 illustrates an example of signaling puncturing mode and segment position using a TB PPDU according to an embodiment of the present invention. [Figure 29]1 shows an example of subchannel configuration and utilization for TB PPDH transmission according to an embodiment of the present invention. [Diagram 30] 13 illustrates an example of signal detection for a TB PPDU in response to a trigger frame according to one embodiment of the present invention. [Diagram 31] 13 illustrates an example of applying different thresholds to areas where reception is predicted in a signal detection process for a TB PPDU according to an embodiment of the present invention. [Diagram 32] 4 illustrates an example of an error correction method for signal detection according to an embodiment of the present invention. [Diagram 33] 10 is a flowchart illustrating an example of a method for a non-AP STA to transmit a response frame to a trigger frame according to an embodiment of the present invention. [Diagram 34] 10 is a flowchart illustrating an example of a method for an AP STA to receive a response frame to a trigger frame according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The terms used in this specification are selected as general terms that are currently widely used as much as possible in consideration of the functions of the present invention, but this may vary depending on the intentions, customs, or the emergence of new technologies of the engineers in the relevant technical field. In addition, in certain cases, the applicant may arbitrarily select terms, and in such cases, the meanings of the terms will be described in the description of the relevant invention. Therefore, it is clear that the terms used in this specification should be interpreted not simply as terms, but based on the substantial meanings of the terms and the contents of this specification as a whole.

[0031] Throughout the specification, when a certain component is "connected" to another component, this includes not only when it is "directly connected" to another component, but also when it is "electrically connected" with another component therebetween. Furthermore, when a certain component "includes" a certain component, this means that it may further include the other component, not excluding the other component, unless otherwise specified. In addition, limitations such as "greater than" or "less than" based on a specific critical value may be appropriately replaced with "more than" or "less than", respectively, depending on the embodiment. Hereinafter, in the present invention, the terms "field" and "subfield" may be used interchangeably.

[0032] FIG. 1 is a diagram showing a wireless LAN system according to an embodiment of the present invention.

[0033] A wireless LAN system includes one or more Basic Service Sets (BSS), which are a set of devices that can successfully synchronize and communicate with each other. Generally, BSSs are classified into infrastructure BSSs and independent BSSs (IBSSs), and Figure 1 shows an infrastructure BSS.

[0034] As shown in FIG. 1, infrastructure BSS BSS1, BSS2 includes one or more stations STA1, STA2, STA3, STA4, STA5, access points AP-1, AP-2 which are stations providing a distribution service, and a distribution system DS which connects multiple access points AP-1, AP-2.

[0035] A station (STA) is any device including a medium access control (MAC) and a physical layer interface for a wireless medium according to the IEEE 802.11 standard, and in a broad sense includes not only non-AP stations but also APs. In this specification, the term "terminal" refers to either a non-AP or an AP, or both. A station for wireless communication includes a processor and a communication unit, and further includes a user interface unit and a display unit, etc., depending on the embodiment. The processor generates frames to be transmitted through a wireless network, processes frames received through the wireless network, and performs various other processes for controlling the station. The communication unit is functionally connected to the processor and transmits and receives frames through the wireless network for the station. In the present invention, the term "terminal" is used to include a user equipment (UE).

[0036] An access point (AP) is an entity that provides a connection to a distribution system DS via a wireless medium for a station associated therewith. In an infrastructure BSS, communication between non-AP stations is generally performed via the AP, but when a direct link is set up, direct communication is possible between non-AP stations. Meanwhile, in the present invention, AP is used as a concept including a personal BSS coordination point (PCP), but in a broad sense, AP includes all concepts such as a central controller, a base station (BS), a node B, a base transceiver system (BTS), or a site controller. In the present invention, AP is also referred to as a base wireless communication terminal, but in a broad sense, the base wireless communication terminal is used as a term including an AP, a base station, an eNodeB (eNB), and a transmission point TP. In addition, the base wireless communication terminal includes various types of wireless communication terminals that allocate communication medium resources and perform scheduling in communication with a plurality of wireless communication terminals.

[0037] A plurality of infrastructure BSSs are connected to each other via a distribution system DS. In this case, a plurality of BSSs connected to each other via the distribution system is called an Extended Service Set (ESS).

[0038] 2 is a diagram showing an independent BSS, which is a wireless LAN system according to another embodiment of the present invention, in which the same or corresponding parts in the embodiment of FIG. 2 are the same as or correspond to the embodiment of FIG.

[0039] BSS3 shown in Figure 2 is an independent BSS and does not include an AP, so all stations (STA6, STA7) are not connected to an AP. An independent BSS is not allowed to connect to a distribution system and forms a self-contained network. In an independent BSS, each station (STA6, STA7) is directly connected to each other.

[0040] 3 is a block diagram showing a configuration of a station 100 according to an embodiment of the present invention. As shown in the figure, the station 100 according to the embodiment of the present invention includes a processor 110, a communication unit 120, a user interface unit 140, a display unit 150, and a memory 160.

[0041] First, the communication unit 120 transmits and receives wireless signals such as wireless LAN packets, and may be built into or externally provided in the station 100. According to an embodiment, the communication unit 120 may include at least one communication module using different frequency bands. For example, the communication unit 120 may include communication modules of different frequency bands such as 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz. According to an embodiment, the station 100 may include a communication module using a frequency band of 7.125 GHz or more and a communication module using a frequency band of 7.125 GHz or less. Each communication module may perform wireless communication with an AP or an external station based on the wireless LAN standard of the frequency band supported by the communication module. The communication unit 120 may operate only one communication module at a time or operate multiple communication modules simultaneously according to the performance and requirements of the station 100. When the station 100 includes multiple communication modules, each communication module may be provided in an independent form, or multiple modules may be integrated into one chip. In an embodiment of the present invention, the communication unit 120 may represent a radio frequency (RF) communication module that processes RF signals.

[0042] Next, the user interface 140 includes various types of input / output means provided in the station 100. That is, the user interface unit 140 receives user input using various input means, and the processor 110 controls the station 100 based on the received user input. Also, the user interface unit 140 performs output based on a command from the processor 110 using various output means.

[0043] Then, the display unit 150 outputs an image on a display screen. The display unit 150 outputs various display objects such as a user interface based on the contents performed by the processor 110 or a control command of the processor 110. The memory 160 also stores control programs used by the station 100 and various data associated therewith. Such control programs include connection programs required for the station 100 to connect to an AP or an external station.

[0044] The processor 110 of the present invention executes various commands or programs to process data within the station 100. The processor 110 also controls each unit of the station 100 and controls transmission and reception of data between the units. According to an embodiment of the present invention, the processor 110 executes a program for connection with an AP stored in the memory 160 and receives a communication setup message transmitted by the AP. The processor 110 also reads information on the priority conditions of the station 100 included in the communication setup message and requests a connection to the AP based on the information on the priority conditions of the station 100. The processor 110 of the present invention may refer to a main control unit of the station 100, or may refer to a control unit for individually controlling some components of the station 100, for example, the communication unit 120, depending on the embodiment. That is, the processor 110 may be a modem that modulates and demodulates a wireless signal transmitted and received from the communication unit 120, or a modulator and / or demodulator. The processor 110 controls various operations of transmitting and receiving wireless signals of the station 100 according to an embodiment of the present invention. A detailed embodiment of the present invention will be described later.

[0045] The station 100 shown in FIG. 3 is a block diagram according to an embodiment of the present invention, and the separate blocks are used to logically distinguish the elements of the device. Thus, the above-mentioned device elements may be mounted on one chip or multiple chips depending on the design of the device. For example, the processor 110 and the communication unit 120 may be integrated and embodied on one chip, or may be embodied on separate chips. In addition, in an embodiment of the present invention, some components of the station 100, such as the user interface unit 140 and the display unit 150, may be selectively provided in the station 100.

[0046] 4 is a block diagram showing a configuration of an AP 200 according to an embodiment of the present invention. As shown in the figure, the AP 200 according to the embodiment of the present invention includes a processor 210, a communication unit 220, and a memory 260. In FIG. 4, a duplicated description of parts of the configuration of the AP 200 that are the same as or correspond to the configuration of the station 100 in FIG. 3 will be omitted.

[0047] Referring to FIG. 4, the AP 200 according to the present invention includes a communication unit 220 for operating a BSS in at least one frequency band. As described above in the embodiment of FIG. 3, the communication unit 220 of the AP 200 may also include a plurality of communication modules using different frequency bands. That is, the AP 200 according to the embodiment of the present invention may include two or more communication modules using different frequency bands, for example, any of 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz. Preferably, the AP 200 may include a communication module using a frequency band of 7.125 GHz or higher and a communication module using a frequency band of 7.125 GHz or lower. Each communication module may perform wireless communication with a station based on the WLAN standard of the frequency band supported by the communication module. The communication unit 220 may operate only one communication module at a time or operate multiple communication modules simultaneously according to the performance and requirements of the AP 200. In the embodiment of the present invention, the communication unit 220 may represent an RF communication module that processes RF (Radio Frequency) signals.

[0048] Next, the memory 260 stores control programs used in the AP 200 and various data associated therewith. Such control programs include a connection program for managing station connections. Also, the processor 210 controls each unit of the AP 200 and controls transmission and reception of data between the units. According to an embodiment of the present invention, the processor 210 executes a program for connection with a station stored in the memory 260 and transmits a communication setting message to one or more stations. At this time, the communication setting message includes information regarding connection priority conditions of each station. Also, the processor 210 performs connection setting in response to a connection request of a station. According to an embodiment, the processor 210 is a modem or a modulation / demodulation unit that modulates and demodulates wireless signals transmitted and received from the communication unit 220. The processor 210 controls various operations of transmitting and receiving wireless signals of the AP 200 according to an embodiment of the present invention. A detailed embodiment thereof will be described later.

[0049] FIG. 5 is a diagram illustrating a process in which a STA establishes a link with an AP.

[0050] 5, the link between the STA 100 and the AP 200 is set up through three steps: scanning, authentication, and association. First, the scanning step is a step in which the STA 100 acquires connection information of the BSS operated by the AP 200. There are two methods for performing scanning: a passive scanning method in which the STA 100 acquires information using only a beacon message S101 periodically transmitted by the AP 200, and an active scanning method in which the STA 100 transmits a probe request to the AP S103, receives a probe response from the AP S105, and acquires connection information.

[0051] The STA 100 that has successfully received wireless connection information in the scanning step transmits an authentication request (S107a), receives an authentication response from the AP 200, and performs an authentication step (S107b). After the authentication step is performed, the STA 100 transmits an association request (S109a), receives an association response from the AP 200, and performs an association step (S109b). In this specification, association basically means wireless association, but the present invention is not limited thereto, and association in a broad sense includes both wireless association and wired association.

[0052] Meanwhile, an 802.1X-based authentication step S111 and an IP address acquisition step S113 via DHCP are additionally performed. In Fig. 5, the server 300 is a server that processes 802.1X-based authentication with the STA 100, and may be physically connected to the AP 200 or may exist as a separate server.

[0053] FIG. 6 is a diagram showing a Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0054] A terminal performing wireless LAN communication performs carrier sensing before transmitting data to check whether a channel is occupied or not. If a wireless signal of a certain strength or more is detected, the channel is determined to be occupied and the terminal delays access to the channel. This process is called Clear Channel Assessment (CCA), and the level that determines whether or not the signal is detected is called the CCA threshold. If a wireless signal of a strength greater than the CCA threshold is received by the terminal and the terminal is the receiver, the terminal processes the received wireless signal. On the other hand, if no wireless signal is detected from the channel or a wireless signal of a strength less than the CCA threshold is detected, the channel is determined to be idle.

[0055] If the channel is determined to be in an idle state, each terminal having data to transmit performs a backoff procedure after an IFS (Inter Frame Space) time, such as an AIFS (Arbitration IFS) or a PIFS (PCF IFS), depending on the status of each terminal. In some embodiments, the AIFS is used as a configuration to replace the conventional DIFS (DCF IFS). Each terminal waits while decreasing a slot time by a random number determined for the corresponding terminal during the idle interval of the channel, and a terminal that has exhausted all the slot time attempts to access the corresponding channel. The period in which each terminal performs a backoff procedure is called a contention window period.

[0056] If a specific terminal succeeds in accessing the channel, the terminal transmits data through the channel. However, if the terminal attempting access collides with another terminal, the colliding terminals are assigned new random numbers and perform a backoff procedure again. According to one embodiment, the random numbers newly assigned to each terminal are determined within a range (2*CW) twice the range (contention window, CW) of the random numbers previously assigned to the terminal. Meanwhile, each terminal attempts access by performing a backoff procedure again in the next contention window period, and at this time, each terminal performs the backoff procedure from the slot time remaining in the previous contention window period. In this manner, each terminal performing wireless LAN communication can avoid collision with each other on a specific channel.

[0057] Hereinafter, in the present invention, a terminal may be called a non-AP STA, an AP STA, an STA, a receiving device, or a transmitting device, and the present invention is not limited thereto.

[0058] <Examples of various PPDU formats>

[0059] FIG. 7 shows a PPDU format for an extremely high throughput (EHT) wireless LAN according to an embodiment of the present invention.

[0060] 7(a) shows an example of a single / multiple user transmission PPDU format, (b) shows an example of a TB (trigger based) PPDU format, and (c) shows an example of a HE (High Efficient) PPDU format in the previous generation Wi-Fi 802.11ax.

[0061] As shown in (a) to (c) of Figure 7, the PPDU is divided into a preamble and a data portion, and the preamble can commonly include legacy fields for backward compatibility, such as L-STF (Legacy Short Training field), L-LTF (Legacy Long Training field), L-SIG (Legacy Signal field), and RL-SIG (Repeated Legacy Signature field).

[0062] Such a legacy field may be included in the preamble of the HE PPDU of the previous version of 802.11ax as well as the EHT PPDU used in 802.11be, as shown in (a) to (c) of FIG. 7.

[0063] Referring to (a) and (b) of Figures 7, in addition to the legacy fields mentioned above, the EHT PPDUs, 11be MU / SU PPDU and 11be TB PPDU, may further include a U-SIG (Universal Signal field), and as shown in (a) of Figure 7, the SU / MU PPDU may further include an EHT-SIG field.

[0064] The U-SIG is a field newly introduced in 802.11be, which is a very high-speed communication standard, and is a field commonly included in subsequent generations of 802.11 standard PPDUs including 802.11be. The U-SIG field may be continuously included in EHT PPDUs and subsequent generations of WLAN PPDUs, and serves to distinguish which generation of PPDUs, including 802.11be, the PPDU belongs to. The U-SIG field can transmit a total of 52 bits of information in 64FFT-based OFDM 2 symbols. Some fields of the U-SIG field may be interpreted differently depending on the PPDU type, whether or not multi-user transmission is performed, and whether or not OFDMA transmission is performed.

[0065] The EHT-SIG field may be functionally composed of an EHT-VD common field, an EHT-RU (resource unit) allocation subfield, and an EHT-User specific field, and the analysis of some fields may change or some fields may be omitted depending on the type of PPDU, whether or not multi-user transmission is performed, and whether or not OFDMA transmission is performed.

[0066] In this case, the EHT-VD common field and the EHT-RU allocation field can be integrated and called the EHT-common field. The configuration and modified (compressed or omitted) form of the EHT-SIG field will be described in detail later using an embodiment. The EHT-RU allocation field can be called the RU allocation field.

[0067] The TB PPDU shown in (b) of FIG. 7 is a trigger-based PPDU, which means a PPDU based on a trigger frame. That is, the PPDU shown in (b) of FIG. 7 is a PPDU transmitted in response to a trigger frame, and the preamble includes only a U-SIG field after a legacy field, but does not include an EHT-SIG field. Therefore, unlike the MU / SU PPDH shown in (a) of FIG. 7, the U-SIG does not include information for decoding the EHT-SIG, and may include spatial reuse, puncturing mode information for indicating the presence or absence of puncturing, and a pattern.

[0068] 7(a) to (c), the terminal may first receive and decode a preamble of a PPDU, and may receive data based on the preamble. For example, the terminal may recognize whether the type of the received PPDU is a SU / MU PPDU based on the U-SIG field included in the preamble, and may recognize the number of content channels constituting the EHT-SIG field based on the recognition. The terminal may then decode the recognized EHT-SIG field to recognize the RUs assigned based on the RU assignment subfield, and may receive data in the recognized RUs.

[0069] FIG. 8 shows a U-SIG field of a TB PPDU according to one embodiment of the present invention.

[0070] 8, the TB PPDU based on the trigger frame may be divided into a preamble and data, and the preamble may include a U-SIG field commonly included in all PPDUs and an EHT-SIG field whose field configuration and inclusion may vary depending on the type of PPDU. In this case, the U-SIG field may include a spatial reuse field for spatial reuse (SR) for PPDU transmission, and a puncturing mode field for indicating the presence or absence of puncturing and the presence or absence and position of puncturing according to each mode.

[0071] Spatial reuse refers to a method of efficiently using spatial resources by a STA adjusting and / or setting an appropriate CCA level according to circumstances, determining whether the channel is idle or occupied based on the adjusted and / or set CCA level, and transmitting a signal. That is, a STA does not apply the same CCA level uniformly to all channels, and adjusts the CCA level lower (or relaxes the criteria for determining whether a channel is idle) when it is determined that the signal transmitted by the STA does not cause a large interference effect on other STAs when SR is performed, thereby enabling more efficient use of transmission resources.

[0072] Fig. 8(a) shows an example of the configuration of the U-SIG field. As shown in Fig. 8(a), the U-SIG field may be composed of a version independent field that is not affected by the PHY version, a version dependent field that is affected by the PHY version, a CRC field (4 bits), and a Tail field (6 bits).

[0073] The version independent field may include a PHY VER field (3 bits) for distinguishing the PHY version, a UL / DL field for indicating the UL (Uplink) / DL (Downlink) of the PPDU, a BSS color field, a TXOP field, and a PPDU BW field.

[0074] The BSS color field indicates a BSS Color index of a device that transmits or receives a PPDU, and the TXOP field includes timing information related to the time when the PPDU transmission ends. The PPDU BW field may include bandwidth information in which the PPDU is transmitted. If a portion of a frequency band in the bandwidth indicated by the PPDU BW field is punctured or not allocated, the frequency band may not be used for transmitting the PPDU. In this case, the PPDU BW may further indicate information regarding the portion of the bandwidth to be punctured.

[0075] Since the version-independent field does not change depending on the type of PPDU, it may be included in the MU / SU PPDU as well as the TB PPDU, and may also be included in the PPDU used in standards after 11be.

[0076] The version dependent field may include a PPDU type field (1b+a bits) and a PPDU type specific field. The PPDU type field indicates the type of the PPDU, and the subfields included in the PPDU type specific field may be changed depending on the type of the PPDU.

[0077] 8B shows an example of a PPDU type specification field of the TB PPDU. Specifically, the PPDU type specification field of the TB PPDU may include a spatial reuse field for spatial reuse and a puncturing mode field for indicating the presence and / or position of puncturing.

[0078] In this case, a plurality of spatial reuse fields may be included according to the bandwidth. For example, as shown in (b) of FIG. 8, four fields, spatial reuse fields 1 to 4, may be included in the PPDU type identification field of the TB PPDU. The values ​​of the spatial reuse fields may be encoded corresponding to each frequency range within the bandwidth indicated by the PPDU BW field of the U-SIG field.

[0079] For example, if the PPDU BW indicates 20 MHz, all of the spatial reuse fields 1 to 4 may be encoded to correspond to the 20 MHz indicated by the PPDU BW. Alternatively, if the PPDU BW field indicates a bandwidth of 40 MHz, two spatial reuse fields (e.g., 1 and 3) may be encoded to correspond to the low 20 MHz based on the center frequency of 40 MHz, and the remaining two spatial reuse fields (e.g., 2 and 4) may be encoded to correspond to the high 20 MHz.

[0080] Or, if the bandwidth is indicated by the PPDU BW field as 80 MHz, then each of the four spatial reuse fields may be encoded corresponding to four 20 MHz portions of the 80 MHz.

[0081] If the bandwidth is indicated as 160 MHz by the PPDU BW field, then each of the four spatial reuse fields may be encoded corresponding to four 40 MHz portions of the 160 MHz.

[0082] When the bandwidth is indicated as 260 MHz by the PPDU BW field, the four spatial reuse fields may be encoded to correspond to three 20 MHz of the twelve 20 MHz of 240 MHz. In this case, the three 20 MHz corresponding to spatial reuse field 1 may be the three 20 MHz channels having the lowest frequency components within the bandwidth of 240 MHz. Alternatively, the remaining three spatial reuse fields may be encoded to correspond to three 80 MHz of 240 MHz, and the remaining one spatial reuse field may be encoded to the same value as the three encoded spatial reuse fields.

[0083] If the PPDU BW field indicates a bandwidth of 320 MHz, each of the four spatial reuse fields may be encoded to correspond to four 80 MHz of the 320 MHz, where the 80 MHz corresponding to spatial reuse field 1 may have the lowest frequency content of the 320 MHz, and the 80 MHz corresponding to spatial reuse field 4 may have the highest frequency content.

[0084] The puncturing mode field indicates the presence and / or location of puncturing and may be encoded to the same value as the puncturing mode field of the trigger frame.

[0085] In this case, the discontinuous form of PPDUs indicated by the puncturing mode field of the trigger frame and the combined form of TB PPDUs transmitted by multiple users in the uplink (PPDU reception form) may change. The reason why the discontinuous form of PPDUs indicated by the puncturing mode and the combined form of TB PPDUs are changed is that some or all of the RUs designated by the RA-RU (Random Access, RU) are not occupied by the STA, and a discontinuous form (unused bandwidth form) not indicated by the puncturing mode may occur.

[0086] The Puncturing Mode field of the TB PPDU may be used by the AP and STA of adjacent BSSs to determine which bandwidths are (definitely) unused among the bandwidths included in the UL BW of the TB PPDU.

[0087] Figure 8 (c) shows an example of a user-specific field of a TB PPDU. Referring to Figure 8 (c), the TB PPDU may include a spatial reuse field that differs depending on the location (bandwidth region) of the RU to which it is transmitted or the type of the TB PPDU. That is, the spatial reuse field included in the TB PPDU may be differentiated depending on the transmission location of the TB PPDU and / or the type of the TB PPDU.

[0088] Specifically, as shown in FIG. 8(b), the spatial reuse field of the TB PPDU for an uplink bandwidth of 320 MHz is composed of Spatial Reuse 1, 2, 3, and 4, and when only four are present, each spatial reuse field corresponds to 80 MHz.

[0089] However, by differentiating the spatial reuse fields of the TB PPDUs transmitted by the primary and secondary, a total of eight spatial reuse fields may correspond to the uplink bandwidth of 320 MHz. Therefore, based on the frequency domain in which the PPDU is transmitted, each of the spatial reuse fields, Spatial Reuse 1 to 8, included in the two types of TB PPDUs, may correspond to 40 MHz of the UL TB PPDU BW (BW represented by combining the TB PPDUs transmitted by each STA).

[0090] That is, when a non-AP STA transmits a TB PPDU indicated by a trigger frame transmitted from an AP STA, the non-AP STA can configure and transmit the spatial reuse field and puncturing mode field included in the PPDU type specification field differently depending on the position of the RU in which the TB PPDU is transmitted and / or the type of the TB PPDU.

[0091] For example, if the TB PPDU is a first type TB PPDU in which the RU location where the TB PPDU is transmitted is the primary 160 MHz, the non-AP STA can include spatial reuse fields Spatial Reuse 1 to 4 in the PPDU type specification field of the TB PPDU. However, if the TB PPDU is a second type TB PPDU in which the RU location where the TB PPDU is transmitted is the secondary 160 MHz, the non-AP STA can include spatial reuse fields Spatial Reuse 5 to 8 in the PPDU type specification field of the TB PPDU.

[0092] The first and second types may be distinguished by the PHY version of the TB PPDU or may be the type of PPDU according to the Wi-Fi standard, for example, the first type may be a HE TB PPDU and the second type may be an EHT-TB PPDU.

[0093] A non-AP STA can set Spatial Reuse 1 to 8 based on information included in the trigger frame, and information for setting the spatial reuse field depending on the position of the RU to which the TB PPDU is transmitted and / or the type of the TB PPDU may be included in different fields of the trigger frame.

[0094] As shown in (b) of Figure 8, when a single spatial reuse field corresponds to 80 MHz, if the spatial reuse of other BSSs is restricted by a portion of 20 MHz of the 80 MHz, a question may arise as to whether the spatial reuse of the remaining 60 MHz that can be reused should also be restricted. Therefore, in order to increase the efficiency of spatial reuse, the size of the bandwidth corresponding to the single spatial reuse field may be reduced, and therefore the number of spatial reuse fields corresponding to each bandwidth may also be increased.

[0095] However, when multiple spatial reuse fields are set and transmitted, the size of the U-SIG field increases and signaling overhead increases. Therefore, by setting different spatial reuse fields between the TB PPDUs transmitted at the primary 160 MHz and secondary 160 MHz as shown in (c) of Figure 8, more spatial reuse fields can be set and transmitted without increasing signaling overhead.

[0096] According to one embodiment of the present invention, after receiving a trigger frame indicating an uplink bandwidth of 320 MHz, a TB PPDU of a single STA to be transmitted may be transmitted using only one of the RUs of either the primary 160 MHz or the secondary 160 MHz.

[0097] According to yet another embodiment of the present invention, after receiving a trigger frame indicating an uplink bandwidth of 240 MHz, a TB PPDU of a single STA to be transmitted may be transmitted using only one of the RUs of either Low 160 MHz or High 160 MHz.

[0098] Referring to (c) of FIG. 8, a TB PPDU transmitted by an RU in the primary 160 MHz may include four spatial reuse fields in the PPDU type specific field, and each of the four spatial reuse fields may correspond to each of the four 40 MHz RUs in the primary 160 MHz.

[0099] In addition, a TB PPDU transmitted by an RU in the secondary 160 MHz may include four spatial reuse fields in the PPDU type specific field, and each of the four spatial reuse fields may correspond to each of the four 40 MHz RUs in the secondary 160 MHz.

[0100] When the bandwidth indicated by the PPDU BW is 240 MHz, the primary BW and the secondary BW may have a bandwidth of 80 MHz. In this case, each of the spatial reuse fields (e.g., 4 spatial reuse fields) of the TB PPDU transmitted in the primary 80 MHz and / or secondary 80 MHz RUs may correspond to each of the subchannels (20 MHz) within the 80 MHz.

[0101] In this embodiment, the PPDU type specific field may further include a puncturing mode field indicating a puncturing mode in addition to the spatial reuse field. In a manner similar to the spatial reuse field, different puncturing mode fields may be included depending on whether the location of the RU from which the STA receiving the trigger frame transmits the TB PPDU is in the primary BW or the secondary BW. That is, the TB PPDU may include a puncturing mode field 1 and a puncturing mode field 2 that are set differently depending on the bandwidth (or segment) in which the RU from which the TB PPDU is transmitted is located.

[0102] For example, as shown in (c) of FIG. 8, puncturing mode field 1 can be included in a TB PPDU transmitted at primary 160 MHz to represent a discontinuous channel shape at primary 160 MHz, and puncturing mode field 2 can be included in a TB PPDU transmitted at secondary 160 MHz to represent a discontinuous channel shape at secondary 160 MHz.

[0103] When a field indicating a puncturing mode is set and transmitted individually according to the bandwidth, as in (c) of Figure 8, the shape of discontinuous channels for the entire uplink bandwidth can be signaled with higher resolution than the method of signaling discontinuous channels using a single puncturing mode field as shown in (b) of Figure 8.

[0104] <Trigger frame format>

[0105] FIG. 9 shows an example of a trigger format according to an embodiment of the present invention.

[0106] 9, the trigger frame may include a frame control field, a duration field, a resource allocation (RA) field, a Timing Advanced field, a Common Information field, a User Information list field, Padding, and an FCS field. The trigger frame may not include some of the above fields, or may further include some fields.

[0107] The Frame Control, Duration, RA and TA fields are identical to the fields contained in the general MAC header of the 802.11 standard.

[0108] The common information field may include information regarding various parameters used when a device that has been allocated a resource unit by a trigger frame transmits a TB PPDU in response thereto.

[0109] The user information list may include at least one User Information field including individual information for each STA. The Padding field may be included to ensure time for generating and preparing a TB PPDU. If a receiving device's own user information field is located at the end of the user information list, the receiving device may not have enough time to recognize an RU assigned to the receiving device and generate and transmit a TB PPDU. Therefore, by additionally placing a Padding field after the user information list field of the trigger frame, it is possible to ensure sufficient time for each receiving device to recognize an RU and prepare a TB PPDU.

[0110] When the receiving device receives the trigger frame, if the received trigger frame is a trigger frame transmitted to itself, it can transmit a TB PPDU in an RU assigned by the trigger frame as a response to the transmitted trigger frame. If the trigger frame is transmitted to multiple receiving devices, the multiple receiving devices receiving the trigger frame can transmit TB PPDUs simultaneously, and the TB PPDUs may be aggregated and transmitted in the form of A (Aggregated)-PPDU. Also, when PPDUs are transmitted from multiple STAs as a response to the trigger frame and received in the form of A-PPDU, the formats of the aggregated TB PPDUs may be different from each other. For example, the HE TB PPDU and the EHT TB PPDU may be aggregated, or TB PPDUs of different types (or formats) may be aggregated and transmitted.

[0111] FIG. 10 shows an example of a configuration of a common information field of a trigger frame according to an embodiment of the present invention.

[0112] The common information field may include information / parameters that are commonly applied to all terminals receiving the trigger frame. As shown in FIG 10, the trigger type field indicates the trigger type of the trigger frame and may be configured with 4 bits.

[0113] Table 1 below shows an example of the type of trigger frame depending on the value of the trigger type field.

[0114] [Table 1]

[0115] Referring to Table 1, the 4 bits of the trigger type field can be encoded from '0000' to '1111' to indicate the type of each trigger frame individually. For example, the 4 bits of the trigger type field can indicate the following types of trigger frames depending on the encoded value: Basic (0), Beamforming Report Poll (1), MU-BAR (2), MU-RTS (3), Buffer Status Report Poll (4), GCR MU-BAR (5), Bandwidth Query Report Poll (6), NDP Feedback Report Poll (7), EHT-Basic (8), EHT-Beamforming Report Poll (9), EHT-MU-BAR (10), MU-RTS (11), EHT-Buffer Status Report Poll (12), EHT-GCR MU-BAR (13), EHT-Bandwidth Query Report Poll (14), and EHT-NDP Feedback Report Poll (15).

[0116] Bit values ​​from '0' to '7' in the trigger type field may indicate the same trigger frame type as the trigger type field of HE (802.11ax). Therefore, when the value of the trigger frame type field, which is an HE trigger frame based on HE, is '0' to '7', the trigger frame may be configured the same as 802.11ax, and therefore the common information field, trigger-dependent common information field, and user field may be configured and encoded in the same format.

[0117] However, the type of trigger frame with a bit value of '8' to '15' in the trigger type field may be indicated only when the PHY version of the trigger frame is EHT (11be). That is, the bit value in the trigger type field may be set to one of the values ​​of '8' to '15' only when the trigger frame is an EHT trigger frame based on EHT. EHT trigger frames based on EHT with trigger type field values ​​of '8' to '15' may have the same functions as the corresponding trigger frames with values ​​of '0' to '7', respectively.

[0118] When the value of the trigger type field is '8' to '15', the EHT trigger frame is based on the EHT, and may include a field (e.g., additional information field) different from the HE trigger field based on the HE with the trigger type field value of '0' to '7'. For example, the trigger frame with the trigger type value of '8' to '15' may further include an additional bandwidth field, a puncturing mode field, and / or an additional UL spatial reuse field for additional spatial reuse, etc. Such additional information field may be used to apply a function newly added to the EHT (e.g., 240 / 320 MHz operation, multiple RU allocation, etc.) to the operation based on the trigger frame.

[0119] The additional information field may be an extension of a field that is functionally the same as a field included in a trigger frame with a trigger type field value of '0' to '7', or may be added using a reserved field.

[0120] As shown in Figure 10, the size of the UL BW field may vary depending on the value of the trigger type field. For example, when the value of the trigger type field is '0' to '7', the size of the UL BW field is 2 bits. However, when the value of the trigger type field is '8' to '15', the size of the UL BW field is 3 bits, which can represent six BW modes (20, 40, 80, 160 (80 + 80), 240 (160 + 80), 320 (160 + 160) MHz).

[0121] The size of the UL spatial reuse field may vary depending on the value of the trigger type field. For example, if the value of the trigger type field is '0' to '7', the size of the UL spatial reuse field is 16 bits. However, if the value of the trigger type field is '8' to '15', the UL spatial reuse field may be composed of eight spatial reuse fields, each 4 bits in size, for a total of 32 bits.

[0122] The reason why the spatial reuse field is composed of a total of eight fields is that if only four spatial reuse fields are used for a 240MHz or 320MHz PPDU as in the past, the BW corresponding to each spatial reuse field reaches a maximum of 80MHz, and spatial reuse cannot be operated efficiently. Therefore, if the spatial reuse field is increased to eight, it will support up to 40MHz, enabling more efficient spatial reuse operation.

[0123] The UL HE-SIG-A2 Reserved field may be utilized as a Puncturing mode field when the Trigger Type is 8 to 15.

[0124] FIG. 11 shows an example of the configuration of an additional information field in the format of a trigger frame according to an embodiment of the present invention.

[0125] Referring to FIG. 11, the trigger frame may include an additional information field depending on whether it is based on HE or EHT, and the additional information field may further include additional information for a response to a TB PPDU based on an EHT trigger frame.

[0126] Specifically, when the value of the trigger type field included in the trigger frame is set to a value between '8' and '15', and the trigger frame is an EHT trigger frame, the trigger frame may further include an additional trigger dependent common information subfield shown in FIG. 11, which is an additional information field.

[0127] As described above, the additional information field may include an additional bandwidth field, a puncturing mode field, and / or an additional UL spatial reuse field for additional spatial reuse, etc. In this case, the common information field other than the additional information field may have the same bit and field configuration in a trigger frame in which the trigger type field has a value of '0' to '7' and in which the trigger type field has a value of '8' to '15'.

[0128] The additional information field shown in FIG. 11 may be commonly included in EHT-based trigger frames whose trigger type field has a value of '8' to '15', and may be included together with BAR Control (20 octets) and BAR Information (20 octets) when the trigger type field has a value of '13' (EHT-GCR MU-BAR).

[0129] The additional information field contains additional information for generating an EHT TB PPDU when the PPDU is transmitted in response to an EHT-based trigger frame. The additional information field may be located immediately after the common information field and may have a size of 1 or 2 bits.

[0130] Also, a specific field located immediately before the additional information field may indicate whether the additional information field is included after the common information field. That is, when the value of the specific field is set to a specific value ('1' or '0'), the non-AP STA may recognize that the additional information field is included after the common information field. In this case, the trigger frame may be recognized as an EHT trigger frame, and the non-AP STA may respond with an EHT TB PPDU. If the specific field indicates that the additional information field is not included, the trigger frame may be recognized as an HE trigger frame, and the non-AP STA may respond with an HE TB PPDU. In this case, the specific field may have a size of 1 bit, and may be 'B63', 'B53', or other bits.

[0131] The non-AP STA can determine whether the additional information field is included after the common information field by the identifier of the additional information field in addition to the specific field. For example, if the value of the identifier of the additional information field (e.g., AID (association identifier)) is set to a specific value (e.g., AID=2007), it may indicate that the additional information field is included after the common information field.

[0132] If the received trigger frame is an HE trigger frame, the non-AP STA can respond using the HE TB PPDU, and can respond using the HE TB PPDU or EHT TB PPDU based on the received trigger frame. In this case, if the location of the RU assigned to transmit the response frame to the trigger frame is located in a bandwidth where the primary channel is not located, the non-AP STA can only transmit the EHT TB PPDU as a response to the trigger frame. That is, if the location of the assigned RU is located in the primary BW, the non-AP STA can respond with the HE TB PPDU or EHT TB PPDU according to the configuration and type of the trigger frame, but if the location of the assigned RU is located in the secondary BW, the non-AP STA can only respond with the EHT TB PPDU.

[0133] For example, the non-AP STA may respond with a TB PPDU or an EHT TB PPDU depending on the format associated with the trigger frame (e.g., if the format of the user information field included in the trigger frame is the HE format or the EHT format). Specifically, after receiving the trigger frame, the non-AP STA may respond with an HE TB PPDU if the format of the user information field included in the trigger frame is the HE format. However, the non-AP STA may respond with an EHT TB PPDU if the format of the user information field included in the trigger frame is the EHT format.

[0134] The additional information field may be referred to as a special user information field, and the fields contained in the additional information field may be interpreted together with the fields contained in the common information.

[0135] The additional UL BW field may be assigned 1 or 2 bits and may be interpreted in combination with the bandwidth field included in the common information field. That is, when the additional UL BW field is included in the additional information field, the non-AP STA can recognize the bandwidth for transmitting the TB PPDU by considering the additional UL BW field in addition to the bandwidth field of the common information field. In this case, 6 of the 8 (or 16) BW modes that can be indicated by 1 bit (or 2 bits) of the additional UL BW field in the 2 bits of the bandwidth field may correspond to 20, 40, 80, 160 (80 + 80), 240 (160 + 80), and 320 (160 + 160) MHz, respectively.

[0136] The additional UL spatial reuse field can signal values ​​for spatial reuse operations for frequency regions not indicated by the UL spatial reuse field of the common field. The UL spatial reuse field of the common information field includes four spatial reuse fields, and the additional UL spatial reuse field includes the other four spatial reuse fields, so that a total of eight spatial reuse fields for the entire bandwidth can be indicated. That is, the multiple spatial reuse fields included in the common information field and the additional UL spatial reuse field included in the additional information field can indicate frequency bands for spatial reuse operations for different bandwidths, respectively.

[0137] For example, when the spatial reuse fields included in the common information field each indicate a frequency band for spatial reuse operation for a primary BW, the additional spatial reuse field included in the additional information field may indicate a frequency band for spatial reuse operation for a secondary BW. Thus, when a non-AP STA transmits a TB PPDU in a primary BW (or when the TB PPDU is an HE TB PPDU), the non-AP STA may generate a TB PPDU using a spatial reuse field included in the common information of the trigger frame. However, when a non-AP STA transmits a TB PPDU in a secondary BW (or when the TB PPDU is an EHT TB PPDU), the non-AP STA may generate a TB PPDU using at least one spatial reuse field included in the additional information field of the trigger frame.

[0138] That is, when a non-AP STA transmits a TB PPDU in response to a trigger frame, the non-AP STA can generate the TB PPDU using at least one spatial reuse field included in a different field depending on whether the responding TB PPDU is an HE TB PPDU or an EHT TB PPDU.

[0139] The puncturing mode field may signal a discontinuous form for the PPDU in which the trigger frame is transmitted. The trigger frame may be transmitted using discontinuous channels excluding some channels in the operating BW, and the discontinuous channel form of the RU in which the trigger frame is transmitted may be indicated by the puncturing mode field.

[0140] Also, the puncturing mode field of the trigger frame may be encoded using the same mode as the puncturing mode field of the SU PPDU, and instead of the puncturing mode field, a bitmap (8-bit or 16-bit bitmap) indicating whether each 20 MHz channel is used to signal the discontinuous channel type of the entire PPDU BW may be included.

[0141] FIG. 12 illustrates an example of a spatial reuse field and a puncturing mode field for uplink transmission according to one embodiment of the present invention.

[0142] 12(a) shows an example of a UL spatial reuse field for uplink spatial reuse operation, which is composed of a total of eight spatial reuse fields. Of the eight spatial reuse fields found in a trigger frame for a bandwidth of 320 (or 160+160) MHz, four can indicate values ​​for spatial reuse corresponding to Low 160 or 80 MHz, and the remaining four can indicate values ​​for spatial reuse corresponding to High 160 or 80 MHz.

[0143] In this case, the multiple spatial reuse fields shown in (a) of Figure 12 may be divided into a UL spatial reuse field included in a common field and an additional UL spatial reuse field included in an additional information field. That is, some fields among the multiple spatial reuse fields may be included in the UL spatial reuse field included in the common field, and the remaining spatial reuse fields may be included in the additional UL spatial reuse field included in the additional information field.

[0144] Each spatial reuse field consists of 4 bits and can indicate a spatial reuse value that applies to a bandwidth of up to 40 MHz.

[0145] For example, in the case of a total bandwidth of 320 MHz, the four spatial reuse fields corresponding to the primary 160 MHz may correspond to the low 40 MHz of the low 80 MHz, the high 40 MHz of the low 80 MHz, the low 40 MHz of the high 80 MHz, and the high 40 MHz of the high 80 MHz, respectively. Similarly, the four spatial reuse fields corresponding to the high 160 MHz may correspond to the lowest 40, the low 40, the high 40, and the highest 40 MHz of the high 160 MHz, respectively.

[0146] When the total bandwidth is 240 (or 160+80 or 80+160) MHz, four of the eight spatial reuse fields included in the trigger frame may correspond to Low 160MHz or Low 80MHz, and the remaining four spatial reuse fields may correspond to High 80MHz or High 160MHz. In this case, the names Low and High are merely expressions used to divide the frequency region into 160MHz+80MHz, and may not be related to the actual frequency positional relationship. In this case, each of the four spatial reuse fields corresponding to 80MHz may be set to a spatial reuse value indicating 20MHz.

[0147] When the total bandwidth is 160 (or 80+80) MHz, four of the eight spatial reuse fields included in the trigger frame correspond to 40 MHz (Lowest 40 MHz, Low 40 MHz, High 40 MHz, Highest 40 MHz), and the remaining four may be encoded to the same value as the spatial reuse field corresponding to each 40 MHz.

[0148] Also, if the trigger frame indicates a bandwidth of 80 MHz, four of the eight spatial reuse fields may correspond to 20 MHz (Lowest 20 MHz, Low 20 MHz, High 20 MHz, Highest 20 MHz), and the remaining four may be encoded to the same value as the spatial reuse fields corresponding to each 20 MHz.

[0149] Also, if the trigger frame indicates a bandwidth of 40 MHz, four of the eight spatial reuse fields may correspond to 20 MHz (Low 20 MHz, High 20 MHz), and the remaining six may be encoded to the same value as the spatial reuse field corresponding to each 20 MHz.

[0150] Also, if the trigger frame indicates a bandwidth of 20 MHz, then all eight spatial reuse fields may indicate a spatial reuse value corresponding to the primary 20 MHz.

[0151] In yet another embodiment of the present invention, the UL spatial reuse field may include four spatial reuse fields, each of which may indicate a spatial reuse value of 80 MHz for a 320 MHz bandwidth, a spatial reuse value of 40 MHz for a 160 MHz bandwidth, and a spatial reuse value of 20 MHz for an 80 MHz bandwidth.

[0152] When a 40 MHz bandwidth is indicated by the trigger frame, two of the spatial reuse fields may correspond to the low or high 20 MHz, and the remaining two may be encoded with the same value as the spatial reuse fields corresponding to each 20 MHz. Also, when a 20 MHz bandwidth is indicated by the trigger frame, all four spatial reuse fields may indicate a spatial reuse value corresponding to the primary 20 MHz.

[0153] FIG. 12(b) shows an example of a puncturing mode field (8 bits or 16 bits). The puncturing mode field indicates the type of discontinuous channel for the PPDU in which the trigger frame is transmitted. That is, the puncturing mode for the bandwidth in which the PPDU, which is the trigger frame, is transmitted may be indicated by the puncturing mode field. Here, the puncturing mode may indicate whether a portion of the entire bandwidth is punctured and the position at which the portion is punctured.

[0154] The puncturing mode field (or a 16-bit bitmap) may be included in the additional information field instead of the (UL HE-SIG-A2) Reserved field of the common information field, and may include two puncturing mode subfields. If two puncturing mode subfields are included, the discontinuous form of the channel on which the trigger frame included in the 320 MHz or 240 MHz PPDU is transmitted is divided into 160 MHz bandwidth sections, and the puncturing mode subfield may indicate whether or not to puncture and the puncturing position.

[0155] FIG. 13 illustrates an example of transmission of a trigger frame and a trigger frame-based TB PPDU according to an embodiment of the present invention.

[0156] Referring to FIG. 13, when a trigger frame is transmitted including multiple spatial reuse fields, each STA can transmit a response frame in response to the trigger frame based on the multiple spatial reuse fields.

[0157] Specifically, STA1 to STA N that receive a trigger frame from an AP STA can check the UL spatial reuse field included in the common information field of the trigger frame, and generate a TB PPDU by encoding the values ​​of the four spatial reuse fields included in the UL spatial reuse field into spatial reuse fields 1 to 4 included in the U-SIG field of the TB PPDU, respectively.

[0158] 14A and 14B show yet another example of transmission of a trigger frame and a trigger frame-based TB PPDU according to an embodiment of the present invention.

[0159] 14A and 14B, when a plurality of spatial reuse fields are indicated using a trigger frame, TB PPDUs may be generated and transmitted / received according to different spatial reuse fields.

[0160] Specifically, a plurality of spatial reuse fields may be transmitted using a trigger frame, some of which may be included in a common information field, and the remaining spatial reuse fields may be included in a supplemental information field.

[0161] In this case, the non-AP STA can generate a response frame using the spatial reuse field included in the common information field or additional information field depending on the location of the RU assigned to it or whether the response frame to the trigger frame is an HE TB PPDU or an EHT TB PPDU.

[0162] For example, if the location of the RU assigned to the non-AP STA is included in the secondary BW or the format associated with the trigger frame is the EHT format (e.g., the format of the user information field is the EHT format), the non-AP STA can generate an EHT TB PPDU using the spatial reuse field included in the additional information field and transmit the generated EHT TB PPDU as a response frame to the trigger frame. However, if the location of the RU assigned to the non-AP STA is included in the primary BW or the format associated with the trigger frame is the HE format (e.g., the format of the user information field is the HE format), the non-AP STA can generate an HE TB PPDU using the spatial reuse field included in the common information field and transmit the generated HE TB PPDU as a response frame to the trigger frame.

[0163] For example, as shown in Fig. 14A, among non-AP STAs STA1 to STA N that receive a trigger frame, STA1 to STA n whose RUs assigned by the trigger frame are located at low 160 MHz or low 80 MHz based on the center frequency select spatial reuse fields 1 to 4 corresponding to low 180 MHz or low 80 MHz from among eight spatial reuse fields 1 to 8 included in the trigger frame. STA1 to STA n can encode the selected spatial reuse fields 1 to 4 into spatial reuse fields 1 to 4 included in the U-SIG field of a TB PPDU, which is a response frame to the trigger frame, respectively.

[0164] In this case, when the TB PPDU generated by STA1 to STA n is an HE TB PPDU, spatial reuse fields 1 to 4 may be spatial reuse fields included in the common information field of the trigger frame, and when the TB PPDU generated by STA1 to STA n is an EHT TB PPDU, spatial reuse fields 1 to 4 may be spatial reuse fields included in the additional information field of the trigger frame.

[0165] As shown in FIG 14B, among non-AP STAs STA1 to STA N that receive the trigger frame, STA n+1 to STA N whose RUs assigned by the trigger frame are located at high 160 MHz or high 80 MHz based on the center frequency select spatial reuse fields 5 to 8 corresponding to high 180 MHz or high 80 MHz from the eight spatial reuse fields 1 to 8 included in the trigger frame. STA n+1 to STA N can encode the selected spatial reuse fields 5 to 8 into spatial reuse fields 1 to 4 included in the U-SIG field of the TB PPDU, which is a response frame to the trigger frame, respectively.

[0166] In this case, when the TB PPDU generated by STA n+1 to STA N is an HE TB PPDU, spatial reuse fields 5 to 8 may be spatial reuse fields included in the common information field, and when the TB PPDU generated by STA1 to STA n is an EHT TB PPDU, spatial reuse fields 5 to 8 may be spatial reuse fields included in the additional information field.

[0167] 14A and 14B, the trigger frame may indicate transmission of an HE TB PPDU and / or an EHT TB PPDU. In this case, at least one non-AP STA that receives the trigger frame may transmit the HE TB PPDU or the EHT TB PPDU in response to the trigger frame. The criteria for the at least one non-AP STA to transmit the TB PPDU or the EHT TB PPDU may be based on the location of the assigned RU and / or the format associated with the trigger frame.

[0168] For example, if the position of the RU assigned by the trigger frame is a secondary BW that does not include a primary channel or the format associated with the trigger frame is an EHT format (e.g., the format of the user information field is the EHT format), an EHT TB PPDU can be generated and transmitted as a response to the trigger frame. However, if the position of the RU assigned by the trigger frame is a primary BW that includes a primary channel or the format associated with the trigger frame is an HE format (e.g., the format of the user information field is the HE format), an HE TB PPDU can be generated and transmitted as a response to the trigger frame.

[0169] FIG. 15 is a flow chart illustrating an example of a method for selecting a spatial reuse field for generating a TB PPDU based on a trigger frame according to an embodiment of the present invention.

[0170] Referring to FIG. 15, a STA receiving a trigger frame can decode the preamble of the trigger frame to recognize an RU for uplink transmission, and can generate a TB PPDU using spatial reuse fields of different trigger frames depending on the position of the recognized RU.

[0171] Specifically, the AP STA can transmit a trigger frame instructing transmission of a TB PPDU, and the non-AP STA can receive the trigger frame from the AP STA and decode the received trigger frame (S15010).

[0172] The non-AP STA can then generate a TB PPDU to transmit the TB PPDU indicated by the trigger frame in response to the received trigger frame, and can use information included in the trigger frame to generate the TB PPDU.

[0173] Specifically, the non-AP STA can decode the trigger frame and recognize the RU assigned to transmit its TB PPDU according to the RU assignment information field of the trigger frame. The non-AP STA determines whether the location of the RU assigned to transmit the TB PPDU is in a high frequency band (or a primary BW including a primary channel) or a low frequency band (or a second BW not including a primary channel) based on the center frequency of the entire bandwidth. If the location of the assigned RU is in the high frequency band (or a primary BW), the non-AP STA can generate the TB PPDU by encoding spatial reuse fields 1 to 4 included in the trigger frame into spatial reuse fields 1 to 4 of the TB PPDU (S15020).

[0174] In this case, when the generated TB PPDU is a HE TB PPDU, the spatial reuse fields 1 to 4 of the trigger frame used for generating the TB PPDU may be spatial reuse fields included in the common information field of the trigger frame.

[0175] On the other hand, if the assigned RU is located in a lower frequency band (or Second BW), the non-AP STA can generate a TB PPDU by encoding spatial reuse fields 5 to 8 included in the trigger frame into spatial reuse fields 1 to 4 of the TB PPDU (S15030).

[0176] In this case, when the generated TB PPDU is an EHT TB PPDU, the spatial reuse fields 5 to 8 of the trigger frame used for generating the TB PPDU may be spatial reuse fields included in the additional information field of the trigger frame.

[0177] FIG. 16 illustrates an example of spatial reuse operation according to the number of spatial reuse fields for a frequency band according to an embodiment of the present invention.

[0178] 16, depending on the number of spatial reuse fields for the bandwidth for transmitting the PPDU, the region of the bandwidth corresponding to the spatial reuse field and the spatial reuse result of the OBSS may change.

[0179] Specifically, as shown in FIG. 16, there are four OBSSs 1 to 4 having primary channels in a bandwidth of 320 MHz in which a TB PPDU of 320 MHz is transmitted, and each of the four OBSSs 1 to 4 may receive interference of -65, -60, -58, and -50 dBm from the TB PPDU.

[0180] In this case, when only four spatial reuse fields are used, as shown in (a) of FIG. 16, the four spatial reuse fields may be set to values ​​associated with spatial reuse restrictions allowed for 80 MHz. On the other hand, when eight spatial reuse fields are used, as shown in (b) of FIG. 16, the eight spatial reuse fields may be set to values ​​associated with spatial reuse restrictions allowed for 40 MHz. In this case, the value set in the spatial reuse field may be set to the strictest value of the spatial reuse conditions applied to the BW corresponding to the spatial reuse field. Therefore, one spatial reuse field corresponding to 80 MHz may be set to the lower value (the value where spatial reuse is more restricted) of two spatial reuse field values ​​corresponding to two 40 MHz present within 80 MHz.

[0181] As shown in FIG. 16(a), in which four spatial reuse values ​​are used for a bandwidth of 320 MHz by the TB PPDU, the spatial reuse values ​​of the bandwidth in which the primary channel of each STA is located in OBSS1 to OBSS4 may be PSR_DISALLOW, -68 dBm, -68 dBm, and PSR_DISALLOW. In this case, the STA confirms that spatial reuse operation is not permitted in OBSS1 and OBSS4, and does not attempt channel access. Also, OBSS2 and OBSS3 know that spatial reuse is permitted in the band in which their primary channel exists, but cannot perform a backoff procedure for channel access because their own interference is greater than the spatial reuse threshold.

[0182] Meanwhile, as shown in FIG. 16(b) where 8 spatial reuse values ​​are used for a bandwidth of 320 MHz by the TB PPDU, the spatial reuse values ​​of the bandwidth in which the primary channel of each STA is located in OBSS1 to OBSS4 may be -72 dBm, -38 dBm, -41 dBm, and PSR_DISALLOW. In this case, OBSS2 and OBSS3 know that spatial reuse is allowed in the band in which their primary channel exists, and since their own interference (from the TB PPDU) is smaller than the spatial reuse threshold, they can perform transmission after performing a backoff procedure for channel access.

[0183] FIG. 17 illustrates an example of a method for transmitting a trigger frame according to an embodiment of the present invention.

[0184] Referring to (a) to (c) of FIG. 17, the trigger frame may be transmitted in different formats depending on the format and number of resources to be transmitted.

[0185] Specifically, the 11be trigger frame is a MAC frame and may be transmitted over 20, 40, 80, 160, or 320 MHz according to the BW of the PPDU in which the trigger frame is transmitted.

[0186] As shown in (a) of Fig. 17, when a part of the AP's operating BW is occupied by a different device or an OBSS (CCA result: BUSY), the BW of the PPDU in which the trigger frame is transmitted is restricted, and the trigger frame may be transmitted only in a part of the operating BW. This is a problem that occurs when a wide bandwidth channel access method follows a channel bonding method, and by utilizing the puncturing operation of the SU PPDU introduced in 11be, the trigger frame may be transmitted in a wider BW using a channel other than the channel determined to be BUSY.

[0187] As shown in FIG. 17(b), the trigger frame may be transmitted only in the remaining frequency bands except for the channels determined as BUSY as a result of CCA within the operating BW. In this case, the discontinuous form of the PPDU in which the trigger frame is transmitted may be signaled by the EHT PHY indicated before the MAC frame including the trigger frame. In this case, the discontinuous form of the PPDU in which the trigger frame is transmitted may be restricted depending on the discontinuous form of the SU PPDU permitted by the EHT. In addition, the trigger frame may be repeatedly indicated in each 20 MHz PPDU and transmitted in a discontinuous form that is not indicated only in a specific channel (a channel that is BUSY as a result of CCA). In this case, the transmission form of the trigger frame may be a method similar to the U-SIG transmission method indicated in the punctured PPDU.

[0188] As shown in Fig. 17(c), two trigger frames may be transmitted simultaneously. This is because the operating BW of a STA that transmits a TB PPDU using a trigger frame may be included in only a part of the BW of the trigger frame transmitted by the AP. As an example, the operating BW of a STA that transmits a UL MU TB PPDU using a 320MHz trigger frame may be limited to be only within Low 160MHz or High 160MHz.

[0189] In this case, the two trigger frames may be transmitted by dividing the PPDU BW into two regions. The criterion for dividing the PPDU BW into two regions may be whether the BW of one region is 160 MHz. That is, the PPDU BW may be divided so that the BW for one PPDU is 160 MHz.

[0190] In addition, each trigger frame represented in the two regions may be represented in a discontinuous form within each region. In this case, the discontinuous form represented when applied to the two trigger frames may be restricted depending on the discontinuous form of the SU PPDU allowed for the BW including the two trigger frames. For example, in FIG. 17(c), the discontinuous channel form allowed for Trigger 1 may be restricted to only the discontinuous channel form allowed for the 160 MHz SU PPDU.

[0191] FIG. 18 illustrates an example of a TB PPDU including a puncturing mode according to an embodiment of the present invention.

[0192] When the puncturing mode is signaled by the trigger frame, the STA can include information on the puncturing mode acquired by the trigger frame in its TB PPDU when constructing its TB PPDU. For example, as shown in (a) of FIG. 18, when the puncturing mode field is included in the signaling field of the TB PPDU, the OBSS receiving the TB PPDU can recognize the discontinuous form of the channel occupied by all TB PPDUs transmitted together with the TB PPDU only from the 20 MHz TB PPDU signaling information acquired in its primary channel.

[0193] Furthermore, the information on the puncturing mode may be used to more finely divide the frequency region corresponding to the spatial reuse value. For example, when the puncturing mode information is used to acquire whether or not a part of the BW region corresponding to the spatial reuse field is punctured, the BW corresponding to the spatial reuse field may correspond only to the region other than the punctured bandwidth according to the information on the puncturing mode.

[0194] As shown in (b) of FIG. 18, when the puncturing mode information in the puncturing mode field indicates that some BWs have been punctured, the information in the spatial reuse field corresponding to each BW may be applied only to the remaining unpunctured BWs among the corresponding BWs.

[0195] <Dynamic RU TB PPDU>

[0196] UL MU (UL MU-MIMO or UL OFDMA) transmission using trigger frame and TB PPDU is effective in reducing contention between STAs by allowing multiple STAs to perform UL transmission simultaneously, while at the same time solving the problem of excessive overhead that may be induced by Short PPDU (UL) transmission from a single STA. However, unlike general UL PPDU transmission, there is a limitation that each STA must perform UL transmission using an RU assigned by the trigger frame from the AP, not based on its own channel state (IDLE or BUSY).

[0197] The problem of the STA's RU selection being restricted may be due to the fact that the AP's TB PPDU reception procedure is different from a general reception procedure. In order to facilitate understanding of the AP's TB PPDU reception process, an embodiment of a procedure in which a STA that receives a trigger frame responds with a TB PPDU and an operation in which the AP receives the TB PPDU transmitted by each STA on the UL are shown in Figures 19 and 20, which will be described later.

[0198] FIG. 19 illustrates an example of a procedure for allocating resource units using a trigger frame and responding to a TB PPDU according to an embodiment of the present invention.

[0199] 19, the AP can assign RUs (each 484 tone size RUs) of the low 40 MHz and high 40 MHz bands to STA1 and STA2, respectively, by transmitting a trigger frame using the 80 MHz band confirmed as IDLE. In this case, the trigger frame may be understood as a trigger frame for UL OFDMA TB PPDU, since it assigns RUs located on different frequencies to two STAs.

[0200] After receiving the trigger frame, STA1 and STA2 can decode the received trigger frame and determine that the trigger frame includes two user information fields, one of which is their own user information field. At this time, each STA can recognize its own user information field based on whether the AID12 subfield of the user information field includes information related to its own AID (e.g., its own AID LSB 12 bits).

[0201] STA1 can confirm that the RU assigned to it is a 484-tone RU located in the low 40 MHz based on the RU assignment subfield included in its user information field, and STA2 can recognize that the RU assigned to it is a 484-tone RU located in the high 40 MHz in the same manner as STA1.

[0202] In addition, the trigger frame can include not only information related to the RU (and SS (Spatial stream)) assigned to each STA, but also various encoding parameters and PPDU length information that each STA must apply when generating a TB PPDU in response to the trigger frame. Each STA decodes the trigger frame to confirm the RU assigned to it, and then generates a TB PPDU by applying the encoding parameters indicated by the trigger frame. The generated TB PPDUs of each STA are simultaneously transmitted over the UL, and the AP can receive a UL OFDMA PPDU in which the TB PPDUs transmitted by each STA are combined.

[0203] Considering the above-described brief description of the trigger frame transmission and the UL OFDMA PPDU reception procedure, the AP must separate the received OFDMA TB PPDU into TB PPDUs for each STA in order to obtain the TB PPDUs transmitted by each STA via the UL. However, the MAC of the AP, which is the entity that generates the trigger frame, knows the location and type of the RUs that it has assigned to each STA, but the PHY of the AP, which is the entity that separates and decodes the OFDMA TB PPDU, does not know the configuration of the OFDMA TB PPDU that it receives. Therefore, the conventional 11ax standard defines a procedure in which the MAC sublayer of the AP generates a trigger frame, requests the PHY layer to transmit it, and then provides the PHY layer with information required to receive the TB PPDU that is expected to be received in response to the transmitted trigger frame.

[0204] In 11ax, after the MAC requests transmission of the trigger frame, it issues a PHY-TRIGGER.request primitive before receiving the TB PPDU from the STA in response to the trigger frame requesting transmission of the TB PPDU. At this time, PHY-TRIGGER.request is issued to request the PHY entity to set parameters for receiving the TB PPDU.

[0205] The PHY-TRIGGER.request primitive provides a TRIGVECTOR parameter, which includes the BW information (CH_BANDWIDTH) and L-SIG length information (UL_LENGTH) of the expected TB PPDUs. At this time, the PHY performs preparations for receiving the TB PPDUs, such as setting the BW of the Rx mode using the BW information and length information of the TB PPDUs transmitted from the MAC.

[0206] The TRIGVECTOR parameter also includes an AID12_LIST and RU_ALLOCATION_LIST of STAs to which RUs are allocated by the trigger frame. The AID12_LIST and RU_ALLOCATION_LIST are used to distinguish subcarriers in which TB PPDUs of each STA exist from TB PPDUs (OFDMA UL PPDUs) received by the PHY from multiple STAs, so that the PHY can separate the TB PPDUs of each user from the TB PPDUs.

[0207] The TRIGVECTOR includes encoding-related parameters commonly applied to TB PPDUs and MCS information used for the TB PPDU of each STA, and the PHY can decode the TB PPDU of each STA using the encoding-related information.

[0208] Considering that the MAC provides the PHY with information related to the TB PPDUs that are expected to be received using the TRIGVECTOR as described above, the procedure for receiving the TB PPDUs may be different from the procedure for receiving a general PPDU. In other words, unlike when receiving a general PPDU, the PHY does not obtain information for decoding the TB PPDUs being received from the preamble and SIG fields of the TB PPDUs being received, but can wait for and decode the TB PPDUs based on the information provided by the MAC.

[0209] FIG. 20 illustrates an example of a method for receiving a TB PPDU based on a trigger frame according to an embodiment of the present invention.

[0210] Referring to FIG. 20, the PHY of the AP receives the TRIGVECTOR from the MAC sublayer and can receive TB PPDUs predicted based on the information included in the TRIGVECTOR.

[0211] Specifically, as shown in Fig. 20, the MAC sublayer issues a PHY-TRIGGER.request primitive to the local PHY entity, where the TRIGGER.request primitive may be issued after the MAC requests the PHY to transmit a trigger frame and before a TB PPDU is received in response to the trigger frame.

[0212] The PHY that receives the TRIGGER.request primitive from the MAC can recognize that the BW of the TB PPDUs that are predicted to be received is 80 MHz from the CH_BANDWIDTH parameter among the TRIGVECTOR parameters. The PHY then receives the 80 MHz TB PPDUs, and separates the TB PPDUs received by OFDMA into TB PPDUs for each user using the AID12_LIST and RU_ALLOCATION_LIST among the TRIGVECTOR parameters received from the MAC.

[0213] The process of separating the TB PPDUs into the TB PPDUs of each STA may be performed using the AID12_LIST parameter and the RU_ALLOCATION_LIST parameter of the TRIGVECTOR parameter. For example, as shown in FIG. 20, the AID12_LIST parameter may include the AID LSB 12 bits of STA1 and STA2 as entries. This allows the PHY to recognize that the TB PPDUs being received are a combination of the TB PPDU of STA1 and the TB PPDU of STA2. In addition, the PHY can determine from the RU_ALLOCATION_LIST information on the form in which the TB PPDUs of STA1 and STA2 are represented, and thereby determine that the RU of the STA is a 484-tone RU located in the low 40 MHz band, and the RU of STA2 is a 484-tone RU located in the high 40 MHz band. Therefore, the PHY can determine the positions of the RUs to which the TB PPDU1 and TB PPDU2 transmitted by STA1 and STA2 are transmitted, and then attempt to decode each of them.

[0214] Considering the above-mentioned TB PPDU reception procedure, reception of TB PPDUs can be completed with only the information transmitted from the MAC of the receiving device to the PHY, so the receiving device can receive the TB PPDU of each STA without decoding the preamble and SIG field of the TB PPDU transmitted by each STA.

[0215] For this reason, the HE-SIG-A field of the 11ax TB PPDU may be configured to include information to aid in the operation of the BSS device (BSS color, TXOP, and 4 spatial reuse fields) instead of information required for receiving and decoding the TB PPDU.

[0216] Thus, unlike typical PPDU reception procedures, reception of a TB PPDU may be based on information provided to the PHY by the MAC of the receiving device, which is the entity that generated the trigger frame, instead of obtaining information from the preamble and SIG fields of the PPDU being received.

[0217] Therefore, if a STA that receives a trigger frame uses an RU other than the RU assigned by the trigger frame or encodes a PPDU using a parameter value other than the parameter value indicated by the trigger frame, a device that receives TB PPDUs after transmitting the trigger frame will not be able to receive and process the TB PPDUs.

[0218] If a specific STA generates and UL transmits a TB PPDU using an RU other than the RU assigned by the trigger frame, the PHY of the AP that transmitted the trigger frame may fail to separate the TB PPDU transmitted by the specific STA from the OFDMA TB PPDUs received from multiple STAs. Also, if a specific STA encodes a PPDU using parameter values ​​other than those indicated by the trigger frame, the PHY of the AP that transmitted the trigger frame may be able to separate the TB PPDU of the specific STA from the received OFDMA TB PPDU, but may fail to decode it. In order to prevent such a failure to receive the TB PPDU, each STA that receives the trigger frame and then transmits a TB PPDU in response thereto may be limited to generate and transmit the TB PPDU using only the RU assigned to it and the parameter values ​​indicated to it.

[0219] In this way, restricting the STA to use only the RUs allocated and parameters indicated by the trigger frame when responding with a TB PPDU after receiving a trigger frame is essential to ensure that the AP side can successfully receive and decode the TB PPDU responded by the STA. However, in a situation where a hidden node of the AP exists on the STA side, the STA may not be able to efficiently utilize the RUs allocated to it.

[0220] FIG. 21 illustrates yet another example of a method for receiving a TB PPDU based on a trigger frame according to an embodiment of the present invention.

[0221] Referring to FIG. 21, when a hidden node of the AP exists on the STA side, the STA cannot use the RU allocated by the trigger frame of the AP for transmitting the TB PPDU.

[0222] Specifically, the AP can use the trigger frame to allocate RUs with a 996 tone size located in the low 80 MHz band to STA1, and RUs with a 242+(242)+484 tone size located in the high 80 MHz band to STA2. In this case, of the 160 MHz band allocated to STA1 and STA2, the 20 MHz band (RUs with a 242 tone size) that is not allocated to either of the two STAs may be a band in which a subchannel determined to be BUSY exists as a result of CCA performed by the AP before sending the trigger frame.

[0223] The trigger frame transmitted by the AP should be received by the STAs of the BSS operated by the AP, and STA1 and STA2 can recognize their own user information field among at least one user information field included in the user information list field of the received trigger frame by the AID field. At this time, STA1 can recognize that the RU assigned to it is a RU of 996 tone size in the low 80 MHz band from the RU assignment subfield in the confirmed user information field, and STA2 can recognize that the RU assigned to it is a RU of 242 + (242) + 484 tone size located in the high 80 MHz band in the same manner as STA1.

[0224] STA1 and STA2, which recognize the RU assigned to them through the trigger frame, must perform CCA in SIFS, which is the time interval from receiving the trigger frame to responding with a TB PPDU. In this case, the CCA may be ED-based CCA. The STA may perform ED-based CCA only when the CS Required subfield in the common information field of the received trigger frame is 1. ED-based CCA may include either or both of Energy Detect and virtual carrier sense (NAV) per 20 MHz CCA sensitivity.

[0225] In addition, a STA that performs ED-based CCA after an RU is assigned by a trigger frame can either perform ED-based CCA on the entire BW region of the PPDU including the trigger frame, or perform ED-based CCA only on the subchannel including the RU assigned to it by the trigger frame.

[0226] If a STA to which an RU is assigned by a trigger frame performs the above-mentioned CCA and finds that at least one of the 20 MHz subchannels in which the assigned RU is located is considered to be BUSY, the STA cannot transmit a TB PPDU using the assigned RU.

[0227] STA1 and STA2 can perform CCA on the four 20 MHz subchannels in the Low 80 MHz band and the three 20 MHz subchannels in the High 80 MHz band that are assigned to them. As a result of performing CCA on the subchannels in the RU assigned to them, both STAs can confirm that some of the subchannels in the RU assigned to them (one subchannel in the case of STA1, and two subchannels in the case of STA2) are BUSY. In this case, neither STA1 nor STA2 may be able to transmit a TB PPDU.

[0228] In this way, when a STA has 20 MHz subchannels with RUs assigned by the trigger frame that are considered to be BUSY, the STA is also restricted from using subchannels that are considered to be IDLE. For this reason, the restriction that a STA that is assigned RUs by the trigger frame and transmits a TB PPDU in the UL must transmit the TB PPDU using all of its assigned RUs can be a major cause of reduced efficiency of UL OFDMA transmission achieved by trigger frame-TB PPDU exchange.

[0229] In order to solve the problem of STA utilization limitations for RUs allocated by such trigger frames, the present invention proposes a procedure that allows a STA to adaptively change the RU from which it transmits a TB PPDU based on the CCA results of the allocated RU and the 20 MHz subchannels present in the allocated RU.

[0230] In the present invention, the meaning of "20 MHz subchannel present in an RU" may be used to indicate a 20 MHz subchannel in which a subchannel corresponding to an RU is located. That is, there is one 20 MHz subchannel included in a 26, 52, 106, or 242 tone RU, and there are two and four 20 MHz subchannels included in a 484 or 996 tone RU, respectively. In this case, the type of the last used RU determined by the STA based on the CCA result may be determined in consideration of the previously agreed RU configuration. The above-mentioned method of determining the type of the last used RU will be described in detail in accordance with an embodiment to be described later. In brief, in one aspect of the present invention, a STA to which an RU is assigned by a trigger frame may transmit a TB PPDU by using all or a part of the 20 MHz subchannels in an IDLE state present in the assigned RU based on the CCA result, rather than using the assigned RU as it is.

[0231] FIG. 22 illustrates yet another example of a method for receiving a TB PPDU based on a trigger frame according to an embodiment of the present invention.

[0232] Referring to FIG. 22, a device that receives a trigger frame can transmit (response) a TB PPDU using only a portion of the RUs allocated using the trigger frame.

[0233] Specifically, STA1 and STA2 can transmit TB PPDU on UL only using subchannels other than those considered BUSY as a result of CCA among the RUs assigned to them. In this way, the operation of selectively changing the RU configuration used for TB PPDU generation and transmission according to the CCA result for the 20 MHz subchannels in the RUs assigned to them may be an operation that can be implemented without any special performance issues. This is because, in the process of generating a TB PPDU after receiving a trigger frame, the STA does not use the RU configuration confirmed by the trigger frame as it is, but adds only a procedure of updating according to the CCA result, thereby implementing the operation of the STA as shown in FIG. 22.

[0234] In this way, the operation on the STA side can be easily implemented, but the AP may fail to decode the OFDMA PPDU (TB PPDUs) if the RU it assigns to each STA using a trigger frame does not match the RU occupied by the TB PPDU transmitted by each STA, as in one embodiment of Figure 22.

[0235] FIG. 23 illustrates yet another example of a method for receiving a TB PPDU based on a trigger frame according to an embodiment of the present invention.

[0236] Referring to FIG. 23, if the RU assigned by the trigger frame and the RU to which the TB PPDU, which is a response to the trigger frame, is transmitted have different RU configurations, the AP may fail to receive UL OFDMA.

[0237] Considering the TB PPDU reception procedure on the AP side described in Figure 20, the AP's PHY can predict, based on the TRIGVECTOR received from the MAC, that STA1's TB PPDU1 will be received by an RU with a 996 tone size located in the low 80 MHz band, and STA2's TB PPDU2 will be received by an RU with a 242+484 tone size located in the high 80 MHz band.

[0238] Therefore, when the AP starts receiving the UL OFDMA PPDU, it predicts that there is an 80MHz TB PPDU1 in the Low 80MHz band and attempts to decode the 80MHz PPDU, and predicts that there is a TB PPDU2 in the High 80MHz band at 20+(20)+40MHz and attempts to decode the 20+(20)+40MHz PPDU. In this case, the TB PPDU1 and TB PPDU2 transmitted by STA1 and STA2 respectively have a different format from the PPDU that the AP attempts to decode. Therefore, the AP fails to decode the TB PPDU transmitted in response to the trigger frame.

[0239] As described above, in order to solve the problem that the AP cannot decode the TB PPDU transmitted in the UL with another RU configuration determined by each STA instead of the RU configuration allocated using the trigger frame, a signaling or procedure is required that allows the AP to recognize the RU configuration used by each STA. Therefore, the present invention provides a method that allows the AP to recognize the type (RU configuration) of the TB PPDU being received by the signaling field of the TB PPDU when receiving the TB PPDU, and a procedure for the AP to recognize and estimate the TB PPDU type transmitted by each STA by per 20MHz CCA.

[0240] For the sake of brevity, as described above, a STA to which an RU is assigned by a trigger frame does not use the assigned RU as it is, but instead uses only some of the RUs included in the assigned RU for reasons of CCA or implementation to configure and transmit a TB PPDU via UL, which can be called Dynamic TB PPDU configuration and UL transmission. As an example of Dynamic TB PPDU configuration, the configuration of Dynamic TB PPDU means that a STA to which an 80MHz RU is assigned configures a TB PPDU using 60(20+40)MHz RUs other than the 20MHz subchannels determined as BUSY as a result of CCA for the assigned 80MHz RU. In this case, the RUs used when each STA configures a Dynamic TB PPDU may be in a form that excludes some subchannels determined as IDLE among the subchannels in the assigned RU due to not only the CCA result but also limitations of M-RU (Multiple RU) configuration allowed by the standard or implementation limitations. In addition, in addition to the CCA results and M-RU configuration limitations or implementation constraints, if the amount of data to be transmitted by each STA is not large, the STA may configure a Dynamic TB PPDU using only some of the RUs rather than using all of the RUs available for use.

[0241] <Example of Trigger Frame Format for Dynamic TB PPDU>

[0242] After transmitting a trigger frame, the AP that receives Dynamic TB PPDU(s) as a response to the trigger frame, different from a conventional 11ax AP, must grasp the RU configuration in which the Dynamic TB PPDU transmitted by each STA is transmitted, without relying only on the RU information assigned to each STA using the trigger frame. For this purpose, each STA includes information regarding the RU in which the Dynamic TB PPDU configured by itself is transmitted in the preamble, and the AP can confirm the form of the Dynamic TB PPDU transmitted by each STA by receiving / decoding the preamble of the Dynamic TB PPDU transmitted by each STA. At this time, the AP can confirm the form of all RUs represented by the Dynamic TB PPDU only after decoding at least one subchannel represented by the preamble of the Dynamic TB PPDU transmitted by each STA.

[0243] Therefore, when a plurality of Dynamic TB PPDU are responded to by a single trigger frame, the AP must decode the preambles of the plurality of Dynamic TB PPDU responded respectively, and since the operation of decoding a plurality of preambles must be performed in parallel, it inevitably becomes an operation that requires a high level of implementation complexity on the AP side.

[0244] If the AP does not have the ability to process the preamble of the Dynamic TB PPDU transmitted by each STA at once, it cannot decode the Dynamic TB PPDU in which the preamble is not properly processed among the Dynamic TB PPDU. For this reason, when the AP assigns an RU to the STA using the trigger frame, it is necessary to explicitly indicate whether the AP may respond to the STA with a Dynamic TB PPDU at the same time.

[0245] In addition, since the Dynamic TB PPDU is received by the PHY, the AP's MAC can configure a trigger frame and request the PHY to transmit it, and then transmit to the PHY a DYNAMIC_RU_LIST, which indicates whether each RU is capable of receiving the Dynamic TB PPDU, together with the RU_ALLOCATION_LIST, which is a parameter of the TRIGVECTOR.

[0246] FIG. 24 illustrates an example of a user information field of a trigger frame according to one embodiment of the present invention.

[0247] Referring to FIG. 24, a STA to which an RU is assigned by a trigger frame can recognize whether or not to allow a Dynamic TB PPDU response according to a user specific field of the trigger frame.

[0248] Receiving a Dynamic TB PPDU by an AP is an operation that was not supported in the 11ax standard, and may increase the implementation complexity of an AP receiving UL OFDMA PPDUs. Therefore, an AP can signal whether a Dynamic TB PPDU response is allowed in response to a trigger frame it transmits, taking into account its own capability.

[0249] As an example, the AP may use a specific field in the trigger frame to indicate whether or not to allow a STA that responds with a TB PPDU after receiving the trigger frame to transmit a Dynamic TB PPDU.

[0250] Specifically, the AP can use the user information field of the trigger frame to indicate to each STA whether or not to allow a Dynamic TB PPDU response using a specific field included in the trigger frame.

[0251] As shown in FIG. 24, the user information field of the trigger frame may consist of the subfields AID12, RU Allocation, Dynamic TB PPDU Response, UL FED Coding Type, UL EHT-MCS, UL DCM, SS Allocation / RA-RU Information, UL Target RSSI, Reserved, and Trigger Dependent User Info.

[0252] The AID12 field indicates the AID LSB 12 bits of the STA to which the RU is allocated according to the user information field and which must respond with the TB PPDU, and the RU allocation subfield indicates the size and location of the RU used by the STA which must respond with the TB PPDU. At this time, the RU allocation subfield may be interpreted in combination with the UL_BW included in the common information field of the trigger frame.

[0253] In addition, the user information field of the 11be trigger frame is usually composed of subfields having the same or similar functions as the 11ax trigger frame, and the RU allocation subfield and SS allocation / RA-RU information subfield may be used to indicate the M-RU (Multiple RU) added in 11be and the number of antennas added (16).

[0254] The Dynamic TB PPDU Response subfield of the user information field allows a STA, which is assigned an RU by the user information field and must respond with a TB PPDU, to indicate whether or not to allow a Dynamic TB PPDU response using some of the assigned RUs according to its CCA result. In one embodiment, when the Dynamic TB PPDU Resp subfield is set to 1, a Dynamic TB PPDU response is allowed for the STA that received the user information field, and when the subfield is set to 0, a Dynamic TB PPDU response is prohibited.

[0255] As another example, the AP may not need to separately signal to each STA whether a response to a Dynamic TB PPDU is allowed. At this time, each STA can recognize that a response to a Dynamic TB PPDU is allowed and operate only when a SU-RU of 40 MHz or more is allocated to itself by a trigger frame.

[0256] Or, as another example, the AP can indicate to all STAs whether a response to a Dynamic TB PPDU is allowed by a common information field (in the trigger frame) instead of the user information field of each STA. If a STA to which an RU of 40 MHz or more is allocated has the ability to respond to a Dynamic TB PPDU when a response to a Dynamic TB PPDU is allowed by the common information field of the trigger frame, the STA can configure a Dynamic TB PPDU and respond to the trigger frame.

[0257] <Method for Determining Whether a Dynamic TB PPDU is Allowed>

[0258] In addition to the above-mentioned decoding ability-related constraints of the AP, a Dynamic TB PPDU may not be allowed. If the RU allocated to a specific STA using a trigger frame is smaller than 20 MHz (an RU of 242 tone size) or is a 20 MHz RU, the STA to which the RU is allocated may not be able to configure a Dynamic TB PPDU.

[0259] Assuming that a STA is assigned a 20MHz RU, the STA will perform CCA on the 20MHz subchannels in the 20MHz RU and determine that the entire 20MHz RU is IDLE or BUSY. Therefore, the STA assigned the 20MHz RU has no basis to dynamically utilize the RU assigned to it according to the CCA result. Even if the STA can obtain the CCA result for each RU in the 20MHz RU, the preamble of the TB PPDU must be configured in 20MHz units, so there is a problem that the preamble cannot be transmitted except for the small RU determined to be BUSY. Similarly, the STA assigned a RU smaller than 20MHz is also restricted from transmitting the Dynamic TB PPDU for the same reason as the STA assigned the 20MHz RU described above.

[0260] In addition, when the AP allocates the same RU to multiple STAs using a trigger frame, the TB PPDU transmitted by each STA must respond with the same preamble and RU configuration. If multiple STAs allocated with the same RU respond with Dynamic TB PPDUs transmitted with different RU configurations, the AP receiving these Dynamic TB PPDUs may not be able to distinguish the format of the Dynamic TB PPDUs transmitted by each STA. Therefore, when the AP allocates a specific RU to multiple STAs, the AP can indicate the Dynamic TB PPDU Resp. subfield represented in the user information field of each STA as 0 to restrict each STA from responding with a Dynamic TB PPDU with a different RU configuration.

[0261] Alternatively, when the STA is assigned an RU of 40 MHz or more, the STA may perform a procedure to check whether the RU assigned to the STA is a multi-user (MU) RU assigned to other TAs. In this case, the STA may respond with a Dynamic TB PPDU only when the STA confirms that the RU assigned to the STA is a single-user (SU) RU assigned only to the STA.

[0262] Furthermore, even if different RUs are assigned to each STA, if the assigned different RUs are RUs in the same 80MHz RU boundary, the Dynamic TB PPDU response of the STA may be restricted. This may be due to the restriction that different preambles are not represented in the 80MHz segment. If the AP assigns two 40MHz RUs in the 80MHz segment to two STAs using a trigger frame, each STA may respond by configuring different preambles when transmitting a Dynamic TB PPDU. In this case, two different preambles may be represented in the 80MHz segment, which may be an operation against the principle specified in 11be. In this case, the Dynamic TB PPDU response restriction related to the above preamble specification may be applied only to an embodiment related to the preamble configuration of the Dynamic TB PPDU among the embodiments of the present invention described later.

[0263] In addition, the operation of the STA that responds to or receives the aforementioned Dynamic TB PPDU may be an operation that is difficult to implement in an STA having a limited hardware configuration. Therefore, the AP and the STA may exchange information regarding whether to support the Dynamic TB PPDU response and the RU configuration to be supported in the EHT-capability element. At this time, when the Dynamic TB PPDU field of the EHT-capability element is indicated as 1, it may mean that the STA can configure and respond to the Dynamic TB PPDU.

[0264] <Trigger Frame for Dynamic TB PPDU Exchange, TB PPDU Format Example>

[0265] FIG. 25 shows an example of a method for transmitting a TB PPDU based on a trigger frame according to an embodiment of the present invention.

[0266] Referring to FIG. 25, the STA to which the RU is assigned by the trigger frame can respond with a Dynamic TB PPDU.

[0267] Specifically, the operation in which the AP assigns the RU using the trigger frame and the STAs STA1 and STA2 to which the RU is assigned by the trigger frame perform a Dynamic TB PPDU response assumes the same situation as the CCA situation of each STA shown in an embodiment of FIG. 22.

[0268] As shown in Fig. 25, each STA can respond with information about the RU configuration it has used, using the U-SIG field of the Dynamic TB PPDU to which it responds. Referring to (a) of Fig. 25, STA1 can indicate that Dynamic TB PPDU1 will be responded to using 20+(20)+40MHz RUs other than the second 20MHz subchannel among the 80MHz RUs allocated to it, and STA2 can indicate that Dynamic TB PPDU2 will be responded to using the 20MHz RU located at the lowest frequency position among the RUs allocated to it. In this case, if the AP decodes at least one preamble represented in the subchannel of the Dynamic TB PPDU transmitted by STA1 and STA2, the AP can recognize that STA1's Dynamic TB PPDU1 is received in a 20+(20)+40 MHz RU located in the Low 80 MHz, and STA2's Dynamic TB PPDU2 is received in a Low 20 MHz RU among the RUs located in the High 80 MHz.

[0269] As described above, the method of signaling information on the RU type used by each STA when configuring the Dynamic TB PPDU has a problem that the expression of some RU types may be limited due to the limited length of the U-SIG field. If the RU allocated to the STA is 320 MHz and the STA can freely use the 320 MHz allocated to the STA in units of 20 MHz RU to configure the Dynamic TB PPDU, 16 bits must be allocated to accurately represent the type of the Dynamic TB PPDU that the STA allocated to the 320 MHz RU can configure. However, the U-SIG must include a version independent field, a spatial reuse field for OBSS, and a puncturing mode field, etc., and it is impossible to allocate 16 bits to indicate the type of the Dynamic TB PPDU as described above.

[0270] For this reason, the size of the RU type-related field that can be used to indicate the type of Dynamic TB PPDU may be limited, and may have a configuration that eliminates signaling for a specific RU combination. However, in 11be, in consideration of implementation complexity and efficiency, the RU combination (M-RU) that a single STA can use is limited, and most Dynamic TB PPDU types can be expressed with just 4 bits regardless of the RU size assigned to the STA by the limited RU combination.

[0271] 26 illustrates an example of a format of a U-SIG field of a TB PPDU according to an embodiment of the present invention. The format of the U-SIG field of the TB PPDU illustrated in FIG. 26 can be based on the premise that the U-SIG of the TB PPDU may be represented by a different value for each 80 MHz segment.

[0272] 26, the U-SIG of the TB PPDU may include a version independent field. The version independent field may be a field commonly included in the next generation WiFi PPDU regardless of the PHY protocol version and the PPDU type, as described in the embodiment of FIG.

[0273] Additionally, the spatial reuse 1, 2 field indicated in the U-SIG of the TB PPDU may indicate the spatial reuse value applied to the 80 MHz segment in which the TB PPDU is transmitted.

[0274] In addition, puncturing modes 1 and 2 may be indicated in the TB PPDU U-SIG, and puncturing mode 1 may be a field indicated by directly copying / moving the UL_Puncturing mode field value transmitted to each STA by the common information field of the trigger frame. The UL_Punturing mode field may be a puncturing mode value indicated by predicting the form of the UL OFDMA PPDU that the AP receives in response to the trigger frame during the process of generating the trigger frame. That is, the puncturing mode 1 field may be information provided to assist the operation of other devices similar to the spatial reuse field, without the purpose of providing information necessary for the AP to receive the Dynamic TB PPDU. Therefore, the puncturing mode 1 field may be a field indicated by the same value in all (Dynamic) TB PPDUs responded to by the trigger frame.

[0275] Meanwhile, the puncturing mode 2 field is a field in which the STA responding with the Dynamic TB PPDU indicates the type of RU used to configure the Dynamic TB PPDU, and therefore the puncturing mode 2 field of the (Dynamic) TB PPDU U-SIG transmitted by different STAs (in different 80 MHz segments) may have different values. An example of signaling using the puncturing mode 2 field is described below with reference to FIG. 28.

[0276] The Segment location field serves to provide information on the location of the TB PPDU including the detected preamble in the segment of the AP receiving the TB PPDU when the OBSS device detects the preamble of the TB PPDU in a specific segment. An example of signaling using the Segment location field will be described in the example of FIG. 28 below.

[0277] As mentioned above, the RU combination that the STA to which the RU is assigned by the trigger frame can use in the Dynamic TB PPDU configuration may be limited to a specific form in consideration of the complexity and efficiency of implementation. For example, the RU that can be assigned to a single STA using the trigger frame may be limited to Small RUs (RUs with 26, 52, 78, 106, and 132 tone sizes) and 20, 40, 60, 80, 120, and 160 MHz RUs (RUs with 242, 484, 996, 484+996, and 996×2 tone sizes, respectively). In other words, the 100 MHz RU (RUs with 996+242 tone sizes) and the 140 MHz RU (RUs with 242+484+996 tone sizes) may be excluded because they do not have a large gain compared to the 80 MHz RU and the 120 MHZ RU, respectively, and increase the complexity of implementation. In this case, the type of RU allocated to a single STA by the trigger frame of the 240 / 320 MHz PPDU may also be restricted for the above reasons. In this case, the restricted type of RU may be Mandatory Multiple-RU.

[0278] According to one embodiment of the present invention, when a single STA configures a Dynamic TB PPDU using a portion of the RUs allocated to it, the configured Dynamic TB PPDU may be restricted to have a restricted form, and the restricted form of the Dynamic TB PPDU may be signaled in a bitmap of 4 bits in size.

[0279] FIG. 27 illustrates an example of a resource unit configuration and signaling for transmitting a TB PPDU according to an embodiment of the present invention.

[0280] Referring to FIG. 27, a STA is assigned a 160 MHz RU by a trigger frame, and the AP that generated and transmitted the trigger frame already knows the size and location of the RU assigned to the STA.

[0281] If a STA performs CCA on eight 20 MHz subchannels included in an assigned 160 MHz RU after receiving a trigger frame and determines that one or both of the two subchannels at the lowest frequency position are BUSY, the STA can indicate Puncturing mode2 of the Dynamic TB PPDU U-SIG as 0111. In this case, even if only one of the two subchannels at the lowest frequency position is BUSY, the STA must configure a Dynamic TB PPDU using the 120 MHz RU (RU with 484+996 tone size) other than the two subchannels in the assigned 160 MHz RU.

[0282] In yet another embodiment, if a STA performs CCA on eight 20 MHz subchannels included in an assigned 160 MHz RU and can only utilize 80 MHz RUs due to the above-mentioned RU configuration restrictions, the Puncturing mode2 field may be set to 0011 or 1100, and the STA can configure and UL transmit a Dynamic TB PPDU using only the 80 MHz RUs.

[0283] Considering the above-mentioned puncturing mode 2 (RU structure of Dynamic TB PPDU) signaling method using a 4-bit size bitmap of the present invention, it can be seen that the minimum size of the RU that a STA can indicate using the puncturing mode 2 field is 1 / 4 of the RU size allocated to it. Therefore, as in this embodiment, when a STA is assigned a 160 MHz RU and only one of the eight subchannels included in the RU is determined to be IDLE, the STA must give up UL transmission using the Dynamic TB PPDU.

[0284] FIG. 28 illustrates an example of signaling of puncturing mode and segment position using a TB PPDU according to an embodiment of the present invention.

[0285] Referring to FIG. 28, a STA may be assigned an RU by a trigger frame transmitted in a 160 MHz band, and both STAs may transmit a response to the trigger frame using a Dynamic TB PPDU in the U-SIG field including puncturing mode and segment position fields.

[0286] In Figure 28, STA1 is assigned an 80 MHz RU corresponding to Segment 1 located at a lower frequency by the trigger frame, and STA2 is assigned a 20+(20)+40 MHz RU included in Segment 2 located at a higher frequency by the trigger frame. STA1 and STA2 can configure and UL transmit Dynamic TB PPDU1, 2 using the 20+(20)+40 MHz RU and the 20 MHz RU, respectively, according to the CCA result and RU type restrictions.

[0287] In this case, the puncturing mode 1 fields included in the U-SIG fields of the Dynamic TB PPDUs transmitted by STA1 and STA2 respectively have the same value, but the puncturing mode 2 field and the segment position field may be set to different values ​​in both Dynamic TB PPDUs.

[0288] The puncturing mode 1 field included in the Dynamic TB PPDU is a value indicated by the common information field of the trigger frame, and indicates the type information of the UL OFDMA PPDU expected to be responded to by the trigger frame, as described above. Therefore, the puncturing mode 1 field is indicated by the same value in all TB PPDUs responded to by a single trigger frame.

[0289] As described in the embodiment of FIG. 27, the configuration of the puncturing mode 2 field can be signaled with different values ​​to indicate the type of RU used by each STA. Thus, STA1 signals the puncturing mode 2 field as 1011 to indicate that its Dynamic TB PPDU1 is configured using 20+(20)+40 MHz RU located in segment 1, and STA2 signals the puncturing mode 2 field as 1000 to indicate that its Dynamic TB PPDU2 is configured using 20 MHz located in the lowest frequency of segment 2 in which the RU assigned to it exists.

[0290] Also, each STA can use the segment position field to indicate information indicating which segment its own transmitted TB PPDU is located in in the BW in which the TB PPDUs responded to by UL OFDMA are represented. The segment position field may be provided so that a STA that detects a preamble of a specific TB PPDU can confirm information on the frequency domain in which the TB PPDUs transmitted together with the TB PPDU are represented. In this case, the segment position field may be interpreted together with another field, the BW field, included in the TB PPDU U-SIG. In one embodiment, if a STA confirms that the BW of the TB PPDU in the preamble detected by itself is 160 MHz and the segment position field is 00, it can confirm that the TB PPDU detected by itself or the TB PPDUs responded to together with the detected TB PPDU are transmitted over the 160 MHz BW and that the position of the detected TB PPDU is 80 MHz located at the lower frequency.

[0291] One embodiment of the present invention considers a 2-bit embodiment of the segment position field, so that the four segments included in the maximum 320 MHz PPDU can be represented as 00, 01, 10, and 11, respectively, starting from the segment located at the lower frequency. If a specific STA is assigned RUs across two segments as in the embodiment of Figure 27, the specific STA can set the segment position field included in the U-SIG field of the TB PPDU to different values ​​(e.g., 00, 01) depending on the position of each segment.

[0292] As mentioned above, a STA responding to a Dynamic TB PPDU does not configure a TB PPDU U-SIG using the values ​​indicated in the trigger frame requesting the Dynamic TB PPDU, but must configure the U-SIG field after making its own determination on the CCA result and RU configuration.

[0293] Therefore, the operation of a STA responding with a Dynamic TB PPDU may be more complicated than the operation of a STA responding with an 11ax TB PPDU, and delays may occur during this process, making it difficult to respond with the TB PPDU at the specified time (SIFS after the trigger frame).

[0294] To solve this problem, when an AP allows one or more STAs to respond with a Dynamic TB PPDU using a trigger frame, the AP can indicate that the response of the TB PPDU can be initiated at a time other than after a SIFS. For example, when the AP indicates a Delayed response field as 1 in the common info field of the trigger frame, the STAs receiving the trigger frame can respond with a TB PPDU after a PIFS, not after a SIFS.

[0295] In FIG. 28, Dynamic TB PPDU1 and 2 received as a response to the trigger frame may have different U-SIG field configurations, and in order for the AP to understand the type of RU to which Dynamic TB PPDU1 and 2 are transmitted, the AP must decode at least one subchannel representing the two Dynamic TB PPDU1 and 2. However, there is a problem that the AP cannot know which subchannel among the subchannels included in the RU that it has assigned to each STA has been excluded in the process of responding to each Dynamic TB PPDU. Therefore, it is very difficult for the AP to implement the operation of decoding at least one subchannel representing each Dynamic TB PPDU, and in order to alleviate this problem, a subchannel that should be obligatory to be occupied when responding to a Dynamic TB PPDU must be set in advance.

[0296] FIG. 29 shows an example of subchannel configuration and usage for TB PPDH transmission according to one embodiment of the present invention.

[0297] Referring to FIG. 29, the AP allocates one 80MHz RU located in each segment to STA1 to STA4 using a 320MHz trigger frame, and allows each STA to respond with a Dynamic TB PPDU. The AP can instruct each STA to occupy a subchannel to respond with a Dynamic TB PPDU. For example, FIG. 29 shows a situation in which the AP instructs STA1 to occupy the third subchannel and STA2 to STA3 to occupy the first subchannel, and each STA must respond with a Dynamic TB PPDU by occupying the subchannel instructed by the AP among the four subchannels in the segment in which the RU allocated to the STA is located. In the case of STA4 allocated with an 80MHz RU located in segment 4, the CCA result of the first subchannel instructed by the AP (the subchannel located at the lowest frequency in the segment) is determined to be BUSY, so that the STA cannot utilize the 60MHz RU other than the subchannel determined to be BUSY, and gives up transmitting the Dynamic TB PPDU.

[0298] In this way, when a STA responding to a Dynamic TB PPDU is instructed (by the AP) to occupy a mandatory subchannel or sets a previously committed Mandatory subchannel, the AP can reduce a lot of burden in receiving at least one preamble of the simultaneously responded Dynamic TB PPDU. In this case, the Mandatory subchannel of the primary 80 MHz segment may be fixed as the P20 channel. That is, when a STA assigned with an RU including a primary 20 MHz subchannel configures a Dynamic TB PPDU, the configuration of the Dynamic TB PPDU that does not include the primary 20 MHz may be restricted.

[0299] Therefore, depending on its capabilities, the AP can, as described above, set the Mandatory subchannel to reduce the burden on receiving the preamble, or limit the number of STAs that can accept Dynamic TB PPDUs, so as to allow Dynamic TB PPDUs to be responded within the range it can support.

[0300] <Example of Procedure for Receiving Dynamic TB PPDU>

[0301] The above-described Dynamic TB PPDU-related embodiments describe the format of the TB PPDU and the operations of the STAs (AP and non-AP) for the invention in which the AP obtains the information necessary for receiving the Dynamic TB PPDU by decoding the preamble of the TB PPDU transmitted UL by each STA.

[0302] Another embodiment of the present invention, described below, provides a method for the AP to independently understand the RU configuration of the Dynamic TB PPDUs transmitted by each STA. According to an embodiment of the present invention described below, the AP confirms the form represented by the TB PPDU received as a response to the trigger frame transmitted by itself based on the signal strength of the received signal, and compares it with the RU information assigned to each STA, thereby enabling the AP to understand the RU configuration of the Dynamic TB PPDUs transmitted UL by each STA.

[0303] To describe in more detail the method for receiving the Dynamic TB PPDU proposed by the present invention, since the AP has assigned RUs to each STA using the trigger frame, it can calculate the reception time and BW of the TB PPDUs whose reception is predicted based on the information of the trigger frame generated by itself. Also, in the TB PPDUs whose reception is predicted, the position information represented by the TB PPDU transmitted UL by each STA is known in advance.

[0304] In this way, considering the situation where the AP knows the RU location of the TB PPDU transmitted by each STA, when the TB PPDU is received as a response to the trigger frame, the AP attempts to detect a signal on the subchannel predicted to represent the TB PPDU, thereby confirming whether the predicted TB PPDU is represented or whether some subchannels are unused, and by confirming that the RU allocated to a specific STA is not utilized, it can recognize that the unused RU has been excluded from the TB PPDU configuration. As a simple example, after the AP allocates an 80MHz RU to a specific STA using a trigger frame, it can predict that an 80MHz TB PPDU will be responded to as a response to the trigger frame. In this case, signal detection can be performed on four subchannels existing in the 80MHz RU where the TB PPDU is expected to be responded, and if signals are detected only in three subchannels as a result of the signal detection, it can be confirmed that the remaining subchannel, not the three subchannels where the signals are detected, is the subchannel excluded in the process of the STA configuring the Dynamic TB PPDU.

[0305] In this way, when the AP independently determines the type of TB PPDU responded by each STA using signal detection, a STA that responds with a Dynamic TB PPDU after receiving a trigger frame does not need to separately provide the AP with information related to the RU configuration of the Dynamic TB PPDU it transmits.

[0306] Another aspect of the effect obtained by utilizing the present invention is that the AP can discontinue additional processing for TB PPDUs that are determined to be undecodable among the TB PPDUs transmitted by each STA via UL based on the signal detection result for the received TB PPDU.

[0307] FIG. 30 illustrates an example of signal detection for a TB PPDU in response to a trigger frame according to one embodiment of the present invention.

[0308] Referring to (a) of Figure 30, the AP uses a 160 MHz trigger frame to allocate 80 MHz RUs in segment 1 and 20+(20)+40 MHz RUs in segment 2 to STA1 and STA2, respectively (allowing Dynamic TB PPDU response), and STA1 and STA2 that receive the trigger frame respond with Dynamic TB PPDU1 and 2, respectively.

[0309] In this case, since the AP already knows that the TB PPDU will be received over the 160 MHz BW after the AP transmits the trigger frame, the AP may attempt signal detection to determine the RU configuration in which the Dynamic TB PPDU will be received. In this case, the signal detection method performed by the AP may be an operation similar to that of per 20 MHz CCA.

[0310] When performing signal detection, the AP can use information on the timing at which the TB PPDU will be received as well as the BW of the TB PPDU that is predicted to be received. In the conventional 11ax standard, a STA that is assigned an RU by a trigger frame must respond with a TB PPDU using the assigned RU after SIFS. Considering the time regulation for the TB PPDU response, the AP can predict that the TB PPDU will be received after a specific time (e.g., SIFS (+ propagation delay)) from the end of the transmission of the trigger frame after transmitting the trigger frame.

[0311] Therefore, the AP can specify the range (frequency and time) of the signal detection operation by using the predicted BW information and predicted reception timing information of the TB PPDUs that are predicted to be received. In this case, the AP can attempt signal detection for a part of the time period in which the preamble of the TB PPDU is predicted to be detected based on the predicted reception time information.

[0312] Fig. 30(b) shows an example of a detection result obtained when the AP performs signal detection for a TB PPDU. In a situation where STA1 uses 20+(20)+40MHz RU and STA2 uses 20MHz RU to respond with Dynamic TB PPDU1 and 2 as shown in Fig. 30(a), the signal detection performed by the AP will measure a high signal level in the subchannels used by each STA to configure the Dynamic TB PPDU, and a low signal level in the subchannels not used for Dynamic TB PPDU transmission.

[0313] The AP can determine whether or not the reception of the TB PPDU has started on each subchannel, taking into consideration the strength of the signal detected on each subchannel. As a simple example, as shown in FIG. 30(b), the AP can complete the above-mentioned signal detection based on whether or not the signal detected on each subchannel exceeds a specific threshold. At this time, the signal detection performed by the AP may be performed in accordance with the timing at which the preamble of the TB PPDU is received, and therefore may be performed in a preamble detection (PD) manner, unlike the general per 20MHz CCA, or may perform energy detection (ED), but using a value different from the ED threshold for general PIFS-based channel access.

[0314] As described above, the AP confirms the subchannel on which the reception of the TB PPDU has started using signal detection, and then can predict the RU configuration of the Dynamic TB PPDU transmitted by each STA based on the reception pattern of the confirmed TB PPDU.

[0315] 30, as a result of signal detection, the AP can determine that the TB PPDU is indicated as 1011 in segment 1 and is received as 1000 in segment 2. At this time, since the 80 MHz RU in segment 1 is allocated from STA1 using a trigger frame, the AP can recognize that the Dynamic TB PPDU is responded to using the 20+(20)+40 MHz RU other than one subchannel of the 80 MHz RU allocated to STA1. At this time, the determination of the type of the Dynamic TB PPDU of STA2 may be performed in the same manner as the process of grasping the Dynamic TB PPDU of STA1 described above.

[0316] The above-mentioned Dynamic TB PPDU type identification process will be briefly described in relation to the operation performed by the PHY of the AP. After the PHY of the AP receives a request to transmit a trigger frame from the MAC, the RU_ALLOCATION_LIST and DYNAMIC_RU_LIST parameters may be delivered by the TRIGVECTOR. Then, the PHY attempts to detect a TB PPDU signal according to a time when the TB PPDU is expected to be responded to, and determines whether the TB PPDU is received on each subchannel. At this time, the signal detection may be limited to only the subchannels where the Dynamic TB PPDU can be received based on the information of the DYNAMIC_RU_LIST parameter.

[0317] Based on the signal detection result, the AP's PHY can modify the RU configuration of the STA confirmed by the RU_ALLOCATION_LIST parameter, and as a result, even if the Dynamic TB PPDU is responded to using an RU with a different configuration than the RU allocated by the MAC using the trigger frame, the PHY can properly separate and decode the TB PPDU of each STA.

[0318] By utilizing the above-mentioned embodiment of the present invention, the AP can independently receive the Dynamic TB PPDU responded by each STA without additional signaling using the TB PPDU U-SIG. However, the above-mentioned signal detection method as shown in FIG. 30(b) may be somewhat inaccurate, and therefore the AP may erroneously determine the subchannel on which the TB PPDU is received. Therefore, in order to increase the accuracy of the above-mentioned signal detection, a signal detection method that adaptively adjusts and applies a threshold is required.

[0319] FIG. 31 illustrates an example of applying different thresholds to areas where reception is expected in a signal detection process for a TB PPDU according to an embodiment of the present invention.

[0320] Referring to FIG. 31, in a signal detection process for checking whether a TB PPDU has been received, different thresholds may be applied to areas where TB PPDUs of different STAs are expected to be received.

[0321] In Figure 31, the AP may perform signal detection by applying different thresholds to RUs assigned to different STAs. After the AP transmits a trigger frame, a situation may be assumed in which it predicts that STA1 will respond with TB PPDU1 in segment 1 and that STA2 will respond with TB PPDU2 in segment 2. In this case, the AP may apply a threshold of -x dBm to four subchannels where TB PPDU1 is predicted to be received to check whether TB PPDU1 is represented, and apply a threshold of -y dBm to four subchannels where TB PPDU2 is predicted to be received.

[0322] The reason for using different thresholds to detect the TB PPDUs of different STAs is that each STA that receives the trigger frame may have a different distance from the AP, and the UL Target RSSI values ​​indicated by the AP using the User Info field of the trigger frame may be different from each other.

[0323] For example, if the AP instructs STA1 to satisfy -20 dBm by indicating UL Target RSSI as 90, the signal received at -40 dBm may not be the signal detected from the TB PPDU responded by STA1. On the other hand, if the AP instructs STA2 to satisfy -110 dBm by indicating UL Target RSSI as 0, the signal detection result using -40 dBm as the threshold can ignore the TB PPDU signal responded by STA2.

[0324] Therefore, the AP can apply different thresholds to each STA when detecting the TB PPDU to which each STA responds, taking into account the Target RSSI value instructed to each STA. To this end, the MAC of the AP must transmit the RU(subchannel)_(target)RSSI_LIST to the TRIGVECTOR transmitted to the PHY.

[0325] According to the above-described embodiment of the present invention, it is possible to perform signal detection for the TB PPDUs that are responded to using different Target RSSI values. However, if signal interference occurs in some of the subchannels where signal detection is performed by other devices, the signal detection results for the some subchannels may be confirmed to be different from the actual reception form of the TB PPDU.

[0326] In this way, in order to correct signal detection errors that may occur due to signals from other devices, the AP can determine whether a TB PPDU is represented based on a threshold value during the signal detection process, and can also check whether a signal of a certain strength is received on a subchannel where the TB PPDU of each STA is expected to be responded to.

[0327] This is because the WiFi standard recommends that when a PPDU transmitted by a STA (AP, non-AP) has a BW exceeding 20 MHz, the strength of the signal emitted by the PPDU to each subchannel be constant (e.g., maximum deviation +-4 dB), so if there is a subchannel whose signal strength differs by a certain level or more from the signals confirmed in other subchannels, it can be determined that the signal detected from the subchannel is received from another device. In this case, the method of detecting a signal received from another device by comparing the signal strengths can be said to be a signal detection error method using signal flatness.

[0328] FIG. 32 illustrates an example of an error correction method for signal detection according to an embodiment of the present invention.

[0329] Referring to FIG. 32, the AP performs signal detection to confirm the RU configurations of the Dynamic TB PPDUs of STA1 and STA2, and uses different thresholds for the subchannels on which the TB PPDUs of each STA are expected to be received.

[0330] At this time, a non-TB PPDU signal exceeding the threshold (-y dBm) set by the AP for detecting the TB PPDU of STA2 may be detected in segment 2 where the TB PPDU of STA2 is expected to be received.

[0331] However, the PHY of the AP can determine that the strength of the signal confirmed in the first subchannel (the leftmost one in the figure) among the signals detected in segment 2 is different from that of the signals confirmed in the remaining second, third, and fourth subchannels, and can determine that the signals detected in the first subchannel and the remaining subchannels are different signals. In this case, the AP can attempt to decode both the Dynamic TB PPDU transmitted on the UL of STA2 to determine whether it is the 20MHz TB PPDU represented in the first subchannel or the 20+40MHz TB PPDU using the remaining three subchannels.

[0332] Therefore, according to one embodiment of the present invention, the AP can utilize signal detection to determine the RU configuration of the Dynamic TB PPDU transmitted by each STA, and errors that may occur during the signal detection process can be resolved using an error detection method using adaptive threshold adjustment and the smoothness of the WiFi signal.

[0333] FIG. 33 is a flowchart illustrating an example of a method in which a non-AP STA transmits a response frame to a trigger frame according to an embodiment of the present invention.

[0334] Referring to FIG. 33, when a non-AP STA receives a trigger frame instructing transmission of a TB PPDU from an AP, the non-AP STA can respond by generating a TB PPDU according to the type and format of the TB PPDU to be responded to.

[0335] Specifically, a non-AP STA may receive a trigger frame instructing transmission of a TB PPDU from an AP (S33010). The trigger frame may include a common information field including a first plurality of spatial reuse fields. The trigger frame may further include an additional information field including a second plurality of spatial reuse fields, and whether the trigger frame includes the additional information field is identified based on identification information of the trigger frame.

[0336] That is, whether the trigger frame includes the second plurality of spatial reuse fields may be identified according to identification information included in the trigger frame.

[0337] For example, as described above, the trigger frame may include a first plurality of spatial reuse fields (spatial reuse fields 1 to 4) in the common information field, and depending on the identification information (e.g., whether the value of a particular field in the common information field is '1' or the AID value of the additional information field is '2007'), the trigger frame may include an additional information field including a second plurality of spatial reuse fields (spatial reuse fields 5 to 8).

[0338] The configuration of the trigger frame may be the same as the trigger format described in Figures 9 and 11. For example, the trigger frame may include at least one of a common information field, an additional information field, and a user information field, and the configuration of the additional information field and / or the user information field may vary depending on the type and / or format of the trigger frame.

[0339] In this case, the user information field for each non-AP STA may be in EHT format or HE format according to the format of the TB PPDU indicated by the trigger frame.

[0340] In this case, the first plurality of spatial reuse fields included in the common information field may be used to generate the HE TB PPDU when the location of the RU for transmitting the TB PPDU, which is a response to the trigger frame, is the upper frequency band (or the primary BW) or the TB PPDU is the HE TB PPDU. That is, the first plurality of spatial reuse fields may be encoded into the spatial reuse field of the TB PPDU.

[0341] The second plurality of spatial reuse fields for spatial reuse for the second bandwidth included in the additional information field may be used to generate an EHT TB PPDU when the location of the RU for transmitting the TB PPDU, which is a response to the trigger frame, is a lower frequency band (or a primary BW or a secondary BW) or the TB PPDU is an EHT TB PPDU. That is, the second plurality of spatial reuse fields may be encoded in the spatial reuse field of the TB PPDU.

[0342] Alternatively, depending on a format associated with the trigger frame (e.g., the format of the user information field), either the first plurality of spatial reuse fields or the second plurality of spatial reuse fields may be used to generate the TB PPDU, which is a response frame.

[0343] For example, if the format associated with the trigger frame is the HE format (e.g., the format of the user information field is the HE format), the TB PPDU, which is the response frame, is generated as the HE TB PPDU using the first plurality of spatial reuse fields, whereas if the format associated with the trigger frame is the EHT format (e.g., the format of the user information field is the EHT format), the TB PPDU, which is the response frame, is generated as the EHT TB PPDU using the second plurality of spatial reuse fields.

[0344] Thereafter, the non-AP STA may generate a response frame based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields in response to the trigger frame (S33020).

[0345] That is, the non-AP STA may determine a format of a response frame to the trigger frame, and generate a TB PPDU, which is a response frame, according to the determined format. In this case, the TB PPDU, which is a response frame, may be generated based on information obtained from a first plurality of spatial reuse fields or a second plurality of spatial reuse fields. Whether the response frame is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields may be determined based on a format associated with the trigger frame. For example, if the format of the user information field of the trigger frame is the HE format, the format of the TB PPDU may be determined as HE TB PPDU and may be generated based on the first plurality of spatial reuse fields. That is, the response frame may be generated based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

[0346] The first or second plurality of spatial reuse fields for generating the TB PPDU may be selected according to the location of the RU assigned for transmitting the TB PPDU indicated by the trigger frame, i.e., if the location of the RU is in the upper frequency band (or primary BW), the TB PPDU may be generated based on the first plurality of spatial reuse fields, and if the location of the RU is in the lower frequency band (or secondary BW), the TB PPDU may be generated based on the second plurality of spatial reuse fields.

[0347] Thereafter, the non-AP STA may transmit a response frame generated based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields in response to the trigger frame (S34030). Whether the response frame is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields may be determined based on a format associated with the trigger frame.

[0348] If the format associated with the trigger frame is an Extremely High Throughput (EHT) format, a response frame is generated based on information obtained from the second plurality of spatial reuse fields.

[0349] Additionally, if the format associated with the trigger frame is a High Efficiency (HE) format, a response frame is generated based on information obtained from the first plurality of spatial reuse fields.

[0350] In addition, whether the response frame is generated based on information obtained from a first plurality of spatial reuse fields or based on information obtained from a second plurality of spatial reuse fields may be determined based on the position on the frequency axis of the resource unit from which the response frame is transmitted.

[0351] The trigger frame includes a bandwidth field, an additional bandwidth field, and a resource allocation field indicating the resource units from which the response frame is transmitted, and the trigger frame may further include at least one of a puncturing mode field indicating whether or not puncturing is performed in the bandwidth indicated by the bandwidth field and / or the additional bandwidth field, and the puncturing position.

[0352] In addition, the non-AP STA can recognize the resource unit from which the response frame is to be transmitted based on the resource allocation field included in the trigger frame, and can generate a response frame based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields depending on the position on the frequency axis of the resource unit from which the response frame is to be transmitted.

[0353] When a response frame is generated based on a second plurality of spatial reuse fields, the response frame may be transmitted at a bandwidth indicated by a bandwidth field included in the common information field and an additional bandwidth field included in the additional information field.

[0354] The response frame may include a plurality of spatial reuse fields, each of which may be set based on information obtained from a corresponding one of the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

[0355] Whether or not a trigger frame includes the additional information field may be recognized based on whether or not the common information field includes the value of a specific subfield indicating whether or not the additional information field is included and / or whether or not the value of an identifier of the additional information field is set to a specific value.

[0356] Also, the response frame may be transmitted in the form of a TB PPDU as described above, and the TB PPDU may be transmitted in the form of an A(aggregated)-PPDU by combining with at least one TB PPDU transmitted from at least one other non-ATP STA instructed to transmit the TB PPDU by the trigger frame, where the at least one TB PPDU is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields, and the TB PPDU and the at least one TB PPDU are generated based on different spatial reuse fields.

[0357] FIG. 34 is a flowchart illustrating an example of a method for an AP STA to receive a response frame to a trigger frame according to an embodiment of the present invention.

[0358] 34, an AP can transmit a trigger frame instructing transmission of a TB PPDU, and can receive a TB PPDU from at least one non-AP STA in response thereto. In this case, when at least one non-AP STA transmits two or more TB PPDUs, the TB PPDUs can be aggregated and transmitted in the form of an A-PPDU. In addition, the TB PPDUs can be in different formats (e.g., HE TB PPDU, EHT TB PPDU, etc.).

[0359] Specifically, the AP may generate and transmit a trigger frame instructing transmission of a TB PPDU (S34010). The trigger frame may include a common information field including a first plurality of spatial reuse fields. The trigger frame may further include an additional information field including a second plurality of spatial reuse fields, and whether the trigger frame includes the additional information field is identified based on identification information of the trigger frame.

[0360] That is, whether the trigger frame includes the second plurality of spatial reuse fields may be identified according to identification information included in the trigger frame.

[0361] For example, as described above, the trigger frame may include a first plurality of spatial reuse fields (spatial reuse fields 1 to 4) in the common information field, and depending on the identification information (e.g., whether the value of a particular field in the common information field is '1' or the AID value of the additional information field is '2007'), the trigger frame may include an additional information field including a second plurality of spatial reuse fields (spatial reuse fields 5 to 8).

[0362] The configuration of the trigger frame may be the same as the trigger format described in Figures 9 and 11. For example, the trigger frame may include at least one of a common information field, an additional information field, and a user information field, and the configuration of the additional information field and / or the user information field may vary depending on the type and / or format of the trigger frame.

[0363] In this case, the user information field for each non-AP STA may be in EHT format or HE format according to the format of the TB PPDU indicated by the trigger frame.

[0364] In this case, the first plurality of spatial reuse fields included in the common information field may be used to generate the HE TB PPDU when the location of the RU for transmitting the TB PPDU, which is a response to the trigger frame, is the upper frequency band (or the primary BW) or the TB PPDU is the HE TB PPDU. That is, the first plurality of spatial reuse fields may be encoded into the spatial reuse field of the TB PPDU.

[0365] The second plurality of spatial reuse fields for spatial reuse for the second bandwidth included in the additional information field may be used to generate an EHT TB PPDU when the location of the RU for transmitting the TB PPDU, which is a response to the trigger frame, is a lower frequency band (or a primary BW or a secondary BW) or the TB PPDU is an EHT TB PPDU. That is, the second plurality of spatial reuse fields may be encoded in the spatial reuse field of the TB PPDU.

[0366] Alternatively, depending on the format associated with the trigger frame (e.g., the format of the user information field), either the first plurality of spatial reuse fields or the second plurality of spatial reuse fields may be used to generate the TB PPDU, which is a response frame.

[0367] For example, when the format associated with the trigger frame is the HE format (e.g., when the format of the user information field is the HE format), the TB PPDU, which is the response frame, is generated as the HE TB PPDU by using a first plurality of spatial reuse fields, whereas when the format associated with the trigger frame is the EHT format (e.g., when the format of the user information field is the EHT format), the TB PPDU, which is the response frame, is generated as the EHT TB PPDU by using a second plurality of spatial reuse fields.

[0368] Thereafter, the AP may receive at least one response frame (TB PPDU) from at least one non-AP STA in response to the trigger frame (S34020), where the TB PPDU may be generated based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

[0369] A TB PPDU, which is a response frame, may be generated based on information obtained from a first plurality of spatial reuse fields or a second plurality of spatial reuse fields. Whether the response frame is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields may be determined based on a format associated with the trigger frame. For example, if the format of a user information field of a trigger frame is an HE format, the format of a TB PPDU may be determined as an HE TB PPDU and may be generated based on a first plurality of spatial reuse fields. That is, the response frame may be generated based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

[0370] The first or second plurality of spatial reuse fields for generating the TB PPDU may be selected according to the location of the RU assigned for transmitting the TB PPDU indicated by the trigger frame, i.e., if the location of the RU is in the upper frequency band (or primary BW), the TB PPDU may be generated based on the first plurality of spatial reuse fields, and if the location of the RU is in the lower frequency band (or secondary BW), the TB PPDU may be generated based on the second plurality of spatial reuse fields.

[0371] Whether a response frame is generated based on a first plurality of spatial reuse fields or a second plurality of spatial reuse fields may be determined based on a format associated with the trigger frame.

[0372] If the format associated with the trigger frame is an Extremely High Throughput (EHT) format, a response frame is generated based on information obtained from the second plurality of spatial reuse fields.

[0373] Also, if the format associated with the trigger frame is a High Efficiency (HE) format, the response frame is generated based on information obtained from the first plurality of spatial reuse fields, i.e., the response frame may be generated based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

[0374] The first or second plurality of spatial reuse fields for generating the TB PPDU may be selected according to the location of the RU assigned for transmitting the TB PPDU indicated by the trigger frame, i.e., if the location of the RU is in the upper frequency band (or primary BW), the TB PPDU may be generated based on the first plurality of spatial reuse fields, and if the location of the RU is in the lower frequency band (or secondary BW), the TB PPDU may be generated based on the second plurality of spatial reuse fields.

[0375] If the format associated with the trigger frame is an Extremely High Throughput (EHT) format, a response frame is generated based on information obtained from the second plurality of spatial reuse fields.

[0376] Additionally, if the format associated with the trigger frame is a High Efficiency (HE) format, a response frame is generated based on information obtained from the first plurality of spatial reuse fields.

[0377] In addition, whether the response frame is generated based on information obtained from a first plurality of spatial reuse fields or based on information obtained from a second plurality of spatial reuse fields may be determined based on the position on the frequency axis of the resource unit from which the response frame is transmitted.

[0378] The trigger frame includes a bandwidth field, an additional bandwidth field, and a resource allocation field indicating the resource units from which the response frame is transmitted, and the trigger frame may further include at least one of a puncturing mode field indicating whether or not puncturing is performed in the bandwidth indicated by the bandwidth field and / or the additional bandwidth field, and the puncturing position.

[0379] In addition, the non-AP STA can recognize the resource unit in which the response frame is to be transmitted based on the resource allocation field included in the trigger frame, and can generate a response frame based on information obtained from the first plurality of spatial reuse fields or the second plurality of spatial reuse fields depending on the position on the frequency axis of the resource unit in which the response frame is to be transmitted.

[0380] When a response frame is generated based on a second plurality of spatial reuse fields, the response frame may be transmitted at a bandwidth indicated by a bandwidth field included in the common information field and an additional bandwidth field included in the additional information field.

[0381] The response frame may include a plurality of spatial reuse fields, each of which may be set based on information obtained from a corresponding one of the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

[0382] Whether or not a trigger frame includes the additional information field may be recognized based on the value of a specific subfield indicating whether or not the additional information field is included in the common information field and / or whether or not the value of an identifier of the additional information field is set to a specific value.

[0383] Also, the response frame may be transmitted in the form of a TB PPDU as described above, and the TB PPDU may be received in the form of an A (aggregated)-PPDU by combining with at least one TB PPDU transmitted from at least one other non-ATP STA instructed to transmit a TB PPDU by the trigger frame, where the at least one TB PPDU is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields, and the TB PPDU and the at least one TB PPDU are generated based on different spatial reuse fields.

[0384] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative and not limiting in any respect. For example, each component described as a single type may be implemented in a distributed form, and similarly, each component described as a distributed type may be implemented in a combined form.

[0385] The scope of the present invention is indicated by the claims set forth below rather than by the above detailed description, and any modifications or variations derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included within the scope of the present invention.

Claims

1. A terminal of a wireless communication system, A communication module, and a processor configured to control the communication module; The processor, Receiving a trigger frame from an AP (Access Point), the trigger frame includes a common information field including a first plurality of spatial reuse fields; Identifying whether the trigger frame includes a second plurality of spatial reuse fields based on type information indicated by the trigger frame; transmitting a response frame in response to the trigger frame, the response frame is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields based on the type information indicated by the trigger frame; configured to: Terminal.

2. The terminal of claim 1 , wherein if a format associated with the trigger frame is an Extremely High Throughput (EHT) format, the response frame is generated based on the second plurality of spatial reuse fields.

3. The terminal of claim 1 , wherein if a format associated with the trigger frame is a High Efficiency (HE) format, the response frame is generated based on the first plurality of spatial reuse fields.

4. A terminal as described in claim 1, wherein a position in a frequency band to which a resource unit from which the response frame is transmitted is assigned differs depending on whether the response frame is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

5. The terminal of claim 4, wherein when the response frame is generated based on the first plurality of spatial reuse fields, the resource unit from which the response frame is transmitted is allocated within a primary 160 MHz.

6. The terminal described in claim 1, wherein the trigger frame further includes identification information used to indicate the type information.

7. The trigger frame includes a bandwidth field, an additional bandwidth field, a resource allocation field, and a puncturing mode field; the resource allocation field is used to allocate resource units over which the response frame is to be transmitted; The terminal of claim 1 , wherein the puncturing mode field is used to indicate whether puncturing is performed in a bandwidth indicated by the bandwidth field and / or the additional bandwidth field and the position of the puncturing.

8. 2. The terminal of claim 1, wherein when the response frame is generated based on the second plurality of spatial reuse fields, the response frame is transmitted at a bandwidth indicated by a bandwidth field included in the common information field and an additional bandwidth field included in the trigger frame.

9. A method for a terminal to transmit data in a wireless communication system, comprising: receiving a trigger frame from an access point (AP), the trigger frame includes a common information field including a first plurality of spatial reuse fields; identifying whether the trigger frame includes a second plurality of spatial reuse fields based on type information indicated by the trigger frame; transmitting a response frame in response to the trigger frame, the response frame is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields based on the type information indicated by the trigger frame; A method comprising:

10. 10. The method of claim 9, wherein if a format associated with the trigger frame is an Extremely High Throughput (EHT) format, the response frame is generated based on the second plurality of spatial reuse fields.

11. 10. The method of claim 9, wherein if a format associated with the trigger frame is a High Efficiency (HE) format, the response frame is generated based on the first plurality of spatial reuse fields.

12. The method of claim 9, wherein a location in the frequency band to which the resource units from which the response frame is transmitted are assigned differs depending on whether the response frame is generated based on the first plurality of spatial reuse fields or the second plurality of spatial reuse fields.

13. The method of claim 12, wherein when the response frame is generated based on the first plurality of spatial reuse fields, the resource units on which the response frame is transmitted are allocated within a primary 160 MHz.

14. The method of claim 9, wherein the trigger frame further includes identification information used to indicate the type information.

15. The trigger frame includes a bandwidth field, an additional bandwidth field, a resource allocation field, and a puncturing mode field; the resource allocation field is used to allocate resource units over which the response frame is to be transmitted; 10. The method of claim 9, wherein the puncturing mode field is used to indicate whether puncturing is performed in a bandwidth indicated by the bandwidth field and / or the additional bandwidth field and the location of the puncturing.

16. 10. The method of claim 9, wherein when the response frame is generated based on the second plurality of spatial reuse fields, the response frame is transmitted at a bandwidth indicated by a bandwidth field included in the common information field and an additional bandwidth field included in the trigger frame.

Images