Wireless communication method and wireless communication terminal for spatial reuse of overlapping basic service sets

Abstract

The present invention relates to a wireless communication method and a wireless communication terminal for spatial reuse of overlapping basic service sets (OBSS), and more particularly, to a wireless communication method and a wireless communication terminal for efficiently using wireless resources by supporting spatial reuse of overlapping basic service sets. To this end, the present invention provides a wireless communication terminal and a wireless communication method using the same, the wireless communication terminal including: a processor; and a communication unit, wherein the processor receives a trigger frame indicating an uplink multi-user transmission, and transmits a trigger-based PHY protocol data unit (PPDU) in response to the received trigger frame, wherein the trigger-based PPDU includes a spatial reuse parameter for spatial reuse of an overlapping basic service set terminal.

Description

[0001] This application is a divisional application of the patent application with application number 201780022351.4 (PCT / KR2017 / 003662) filed on October 8, 2018, with an international application date of April 3, 2017, and the invention name being “Wireless communication method and wireless communication terminal for spatial reuse of overlapping basic service sets”. Technical Field

[0002] The present invention relates to a wireless communication method and a wireless communication terminal for spatial reuse operation of overlapping basic service sets, and more particularly, to a wireless communication method and a wireless communication terminal for supporting spatial reuse operation of overlapping basic service sets to efficiently use wireless resources. Background Art

[0003] In recent years, with the expansion of mobile devices, wireless LAN technology, which can provide fast wireless Internet services to mobile devices, has gained attention. Wireless LAN technology allows mobile devices, including smartphones, smart tablets, laptops, portable multimedia players, embedded devices, etc., to wirelessly access the Internet at home, work, or in a specific service provider area based on short-range wireless communication technology.

[0004] Since using the frequency of 2.4GHz to support the initial wireless LAN technology, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 has been commercialized or developed various technical standards. First, IEEE 802.11b supports a communication speed of maximum 11Mbps when using the frequency of the 2.4GHz band. Compared with the frequency of the significantly congested 2.4GHz band, the IEEE 802.11a commercialized after IEEE802.11b uses the frequency of the 5GHz band instead of the 2.4GHz band to reduce the influence of interference, and by using OFDM technology, the communication speed is increased to a maximum of 54Mbps. However, the shortcoming of IEEE 802.11a is that the communication range is shorter than that of IEEE802.11b. In addition, similar to IEEE 802.11b, IEEE 802.11g uses the frequency of the 2.4GHz band to achieve a communication speed of maximum 54Mbps and meets backward compatibility to significantly attract attention, and is superior to IEEE 802.11a in terms of communication range.

[0005] In addition, as a technical standard established to overcome the limitations of communication speeds that have been pointed out as weaknesses in wireless LANs, IEEE 802.11n has been provided. IEEE 802.11n aims to improve the speed and reliability of networks and extend the operating range of wireless networks. In more detail, IEEE 802.11n supports high throughput (HT), wherein data processing speeds are a maximum of 540 Mbps or higher, and further, is based on multiple-input and multiple-output (MIMO) technology, wherein multiple antennas are used on both sides of the transmitting unit and the receiving unit to minimize transmission errors and optimize data speed. In addition, the standard can use a coding scheme that sends multiple copies of the data superimposed on each other in order to increase data reliability.

[0006] With the increasing deployment of wireless LANs and the further diversification of wireless LAN application applications, demand has grown for new wireless LAN systems supporting higher throughput (Very High Throughput (VHT)) than the data processing speeds supported by IEEE 802.11n. Among these, IEEE 802.11ac supports a wide bandwidth (80 to 160 MHz) in the 5 GHz frequency band. While the IEEE 802.11ac standard is defined only in the 5 GHz band, initial 11ac chipsets also support operation in the 2.4 GHz band for backward compatibility with existing 2.4 GHz band products. Theoretically, this standard can enable wireless LAN speeds of at least 1 Gbps for multiple stations and a maximum single-link speed of at least 500 Mbps. This is achieved by expanding upon the wireless interface concepts adopted by 802.11n, including wider wireless bandwidth (up to 160 MHz), more MIMO spatial streams (up to 8), multi-user MIMO, and high-density modulation (up to 256QAM). IEEE 802.11ad has also been introduced as a solution for transmitting data using the 60 GHz band instead of the existing 2.4 GHz / 5 GHz band. IEEE 802.11ad is a transmission standard that uses beamforming technology to provide a maximum speed of 7 Gbps and is suitable for streaming high-bitrate moving images such as massive data or uncompressed HD video. However, since the 60 GHz band has difficulty passing through obstacles, its disadvantage is that it can only be used by devices in close proximity.

[0007] Meanwhile, in recent years, discussions have been ongoing on technologies that provide efficient and high-performance wireless LAN communication in high-density environments, as the next-generation wireless LAN standards following 802.11ac and 802.11ad. Specifically, in next-generation wireless LAN environments, high-spectrum-efficient communication is required both indoors and outdoors in the presence of a high density of stations and access points (APs), and various technologies are needed to achieve this communication. Summary of the Invention

[0008] Technical issues

[0009] The present invention has an object to provide high-efficiency / high-performance wireless LAN communication in a high-density environment as described above.

[0010] The present invention has the purpose of resolving the ambiguity of spatial reuse field identification for inter-BSS (or overlapping BSS) terminals receiving a triggered-based PPDU.

[0011] The present invention has the object of providing a wireless communication method and a wireless communication terminal in a high-density environment including overlapping basic service sets.

[0012] Technical Solution

[0013] To achieve these objectives, the present invention provides a wireless communication method and a wireless communication terminal as follows.

[0014] First, an exemplary embodiment of the present invention provides a wireless communication terminal, which includes: a processor; and a communication unit, wherein the processor receives a trigger frame indicating uplink multi-user transmission and sends a trigger-based PHY protocol data unit (PPDU) in response to the received trigger frame, wherein the trigger-based PPDU includes spatial reuse parameters for spatial reuse operation of overlapping basic service set (OBSS) terminals.

[0015] In addition, an exemplary embodiment of the present invention provides a wireless communication method for a wireless communication terminal, comprising: receiving a trigger frame indicating uplink multi-user transmission; sending a trigger-based PHY protocol data unit (PPDU) in response to the received trigger frame; wherein the trigger-based PPDU includes spatial reuse parameters for spatial reuse operation of overlapping basic service set (OBSS) terminals.

[0016] When the total bandwidth through which transmission of the trigger-based PPDU is performed is non-contiguous first and second frequency bands, a spatial reuse parameter for the first frequency band and a spatial reuse parameter for the second frequency band may be set to the same value.

[0017] The High Efficiency Signal Field A (HE-SIG-A) of the triggered PPDU may include multiple spatial reuse fields, and the multiple spatial reuse fields may carry spatial reuse parameters obtained from the trigger frame, and each of the multiple spatial reuse fields may indicate the spatial reuse parameters for a single subband constituting the total bandwidth over which the triggered PPDU transmission is performed.

[0018] The plurality of spatial reuse fields may include a first spatial reuse field, a second spatial reuse field, a third spatial reuse field, and a fourth spatial reuse field, and when the total bandwidth over which the triggered PPDU transmission is performed is a non-contiguous first frequency band and a second frequency band, the first spatial reuse field and the second spatial reuse field of the first frequency band may be set to the same values ​​as the third spatial reuse field and the fourth spatial reuse field for the second frequency band, respectively.

[0019] When the total bandwidth over which the triggered PPDU transmission is performed is less than or equal to the predetermined bandwidth, the spatial reuse field may indicate the spatial reuse parameters for the subband of the first frequency bandwidth, and when the total bandwidth over which the triggered PPDU transmission is performed exceeds the predetermined bandwidth, the spatial reuse field may indicate the spatial reuse parameters for the subband of the second frequency bandwidth wider than the first frequency bandwidth.

[0020] The spatial reuse parameter may be set based on the transmission power of the PPDU containing the trigger frame and the acceptable interference level of the primary wireless communication terminal transmitting the PPDU containing the trigger frame.

[0021] The spatial reuse operation of the OBSS terminal may include an operation of adjusting the transmission power of the OBSS terminal based on the spatial reuse parameter.

[0022] The operation of adjusting the transmission power may be performed based on the received signal strength of the PPDU including the trigger frame measured by the OBSS terminal and the spatial reuse parameter obtained by the OBSS terminal.

[0023] The transmission power of the OBSS terminal may be set to be lower than a value obtained by subtracting the measured received signal strength from the obtained spatial reuse parameter value.

[0024] The OBSS terminal may obtain the spatial reuse parameter from at least one of the trigger frame and the trigger-based PPDU.

[0025] Beneficial effects

[0026] According to the embodiments of the present invention, the ambiguity of the spatial reuse field identification of an inter-BSS (or overlapping BSS) terminal receiving a trigger-based PPDU can be resolved.

[0027] In addition, according to an embodiment of the present invention, if a received frame is determined to be an inter-BSS frame, a spatial reuse operation can be performed, thereby effectively using wireless resources.

[0028] According to the embodiments of the present invention, it is possible to increase the total resource utilization in a contention-based channel access system and improve the performance of a wireless LAN system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A wireless LAN system according to an embodiment of the present invention is illustrated.

[0030] Figure 2 A wireless LAN system according to another embodiment of the present invention is shown.

[0031] Figure 3 The diagram illustrates a configuration of a station according to an embodiment of the present invention.

[0032] Figure 4 FIG. 1 illustrates a configuration of an access point according to an embodiment of the present invention.

[0033] Figure 5 The diagram schematically illustrates the process of link establishment between a STA and an AP.

[0034] Figure 6 The diagram illustrates a carrier sense multiple access (CSMA) / collision avoidance (CA) method used in wireless LAN communications.

[0035] Figure 7 A channel access method using a spatial reuse operation according to an embodiment of the present invention is illustrated.

[0036] Figure 8 FIGURES illustrate an SR operation of a terminal according to an embodiment of the present invention when a PPDU including a trigger frame is transmitted in an OBSS.

[0037] Figure 9 The SR operation of the terminal according to an embodiment of the present invention when a PPDU including a trigger frame is transmitted in an OBSS is illustrated in more detail.

[0038] Figure 10 This diagram illustrates an embodiment in which a terminal performs an SR operation based on a contention procedure when a PPDU including a trigger frame is transmitted in an OBSS.

[0039] Figure 11 An embodiment of an operation in which a terminal sets a NAV when transmitting a PPDU including a trigger frame in an OBSS is illustrated.

[0040] Figure 12 An embodiment of transmitting spatial reuse parameters via a trigger frame and a corresponding trigger-based PPDU is illustrated.

[0041] Figure 13 A method of signaling a spatial reuse field of a trigger-based PPDU according to an embodiment of the present invention is illustrated.

[0042] Figure 14 An embodiment of a method of setting a spatial reuse field of a trigger-based PPDU is illustrated.

[0043] Figures 15 to 19A method of configuring the HE-SIG-A and spatial reuse fields according to an embodiment of the present invention is illustrated.

[0044] Figure 20 Another embodiment of a method of setting a spatial reuse field of a trigger-based PPDU is illustrated.

[0045] Figure 21 Another embodiment of a method of setting and using a spatial reuse field of a trigger-based PPDU is illustrated.

[0046] Figure 22 A method of configuring the HE-SIG-A and spatial reuse fields of a trigger-based PPDU according to another embodiment of the present invention is illustrated.

[0047] Figure 23 A method of signaling a spatial reuse field of a trigger-based PPDU according to another embodiment of the present invention is illustrated.

[0048] Figure 24 A method of signaling a bandwidth field according to an embodiment of the present invention is illustrated. DETAILED DESCRIPTION

[0049] By taking into account the functions of the present invention, the terms used in this specification adopt the general terms currently in wide use. However, the terms may be changed according to the intentions, habits, and emergence of new technologies of those skilled in the art. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in such cases, their meanings will be described in the corresponding description section of the present invention. Therefore, it should be understood that the terms used in this specification should be analyzed not only based on the name of the term, but also based on the substantive meaning of the term and the content of the entire specification.

[0050] Throughout this specification and the claims that follow, when it is described that an element is "coupled" to another element, the element may be "directly coupled" to the other element or "electrically coupled" to the other element via a third element. Furthermore, unless expressly stated to the contrary, the word "comprise" and variations such as "comprising" or "including" will be understood to implicitly include the stated elements but not to exclude any other elements. Furthermore, limitations based on specific thresholds such as "or above" or "or below" may be replaced with "greater than" or "less than," respectively, as appropriate.

[0051] This application claims priority to and the benefit of Korean Patent Applications Nos. 10-2016-0040551, 10-2016-0074091, 10-2016-0086044, and 10-2016-0093813 filed in the Korean Intellectual Property Office, and the embodiments and matters described in the corresponding applications, which formed the basis of the claim of priority, are to be included in the detailed description of this application.

[0052] Figure 1 1 is a diagram illustrating a wireless LAN system according to an embodiment of the present invention. The wireless LAN system includes one or more basic service sets (BSSs), and a BSS represents a group of devices that are successfully synchronized with each other to communicate with each other. Generally, a BSS can be divided into an infrastructure BSS and an independent BSS (IBSS), and Figure 1 The diagram shows the basic structure BSS between them.

[0053] As in Figure 1 As shown in the figure, the infrastructure BSS (BSS1 and BSS2) includes one or more stations STA1, STA2, STA3, STA4 and STA5, access points PCP / AP-1 and PCP / AP-2 of the stations providing distributed services, and a distribution system (DS) connecting multiple access points PCP / AP-1 and PCP / AP-2.

[0054] A station (STA) is a predetermined device that includes a medium access control (MAC) and a physical layer interface for a wireless medium in accordance with the provisions of the IEEE 802.11 standard, and broadly includes both non-access point (non-AP) stations and access points (APs). In addition, in this specification, the term "terminal" may be used to refer to a non-AP STA, or an AP, or both. A station for wireless communication includes a processor and a communication unit, and according to this embodiment, may further include a user interface unit and a display unit. The processor may generate frames to be transmitted via a wireless network, or process frames received via a wireless network, and furthermore, perform various processes for controlling the station. In addition, the communication unit is functionally connected to the processor, and transmits and receives frames via the wireless network for the station. According to the present invention, a terminal may be used as a term that includes a user equipment (UE).

[0055] An access point (AP) is an entity that provides access to a distribution system (DS) via a wireless medium for stations associated with it. In an infrastructure BSS, communication between non-AP stations is generally performed via the AP, but when a direct link is configured, direct communication is even allowed between non-AP stations. Meanwhile, in the present invention, AP is used as a concept that includes a personal BSS coordination point (PCP), and in a broad sense can include concepts including a central controller, base station (BS), node B, base transceiver system (BTS), and site controller. In the present invention, AP can also be referred to as a base station wireless communication terminal. Base station wireless communication terminal can be used as a term that, in a broad sense, includes APs, base stations, eNBs (i.e., eNodeBs), and transmission points (TPs). Furthermore, base station wireless communication terminals can include various types of wireless communication terminals that allocate media resources and perform scheduling for communications with multiple wireless communication terminals.

[0056] Multiple infrastructure BSSs may be connected to each other via a distribution system (DS). In this case, the multiple BSSs connected via the distribution system are called an extended service set (ESS).

[0057] Figure 2 The figure shows an independent BSS according to another embodiment of the present invention, which is a wireless LAN system. Figure 2 In the embodiment of Figure 1 Repetitive description of parts of the embodiments will be omitted.

[0058] Because in Figure 2 The BSS3 shown in FIG is an independent BSS and does not include an AP. All stations STA6 and STA7 are not connected to the AP. Independent BSSs are not allowed to access the distribution system and form a self-contained network. In an independent BSS, corresponding stations STA6 and STA7 can directly connect to each other.

[0059] Figure 3 is a block diagram illustrating the configuration of a station 100 according to one embodiment of the present invention. Figure 3 As illustrated in FIG, a station 100 according to an embodiment of the present invention may include a processor 110 , a communication unit 120 , a user interface unit 140 , a display unit 150 , and a memory 160 .

[0060] First, the communication unit 120 transmits and receives wireless signals, such as wireless LAN packets, and can be embedded in the station 100 or provided as a peripheral. Depending on the embodiment, the communication unit 120 may include at least one communication module that uses different frequency bands. For example, the communication unit 120 may include communication modules with different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. According to one embodiment, the station 100 may include a communication module that uses a frequency band of 6 GHz or above, and a communication module that uses a frequency band of 6 GHz or below. The respective communication modules may perform wireless communications with an AP or external station according to the wireless LAN standard of the frequency band supported by the respective communication module. Depending on the performance and requirements of the station 100, the communication unit 120 may operate only one communication module at a time, or may operate multiple communication modules simultaneously. When the station 100 includes multiple communication modules, each communication module may be implemented as a separate component, or the multiple modules may be integrated into a single chip. In embodiments of the present invention, the communication unit 120 may represent a radio frequency (RF) communication module for processing RF signals.

[0061] Second, the user interface unit 140 includes various types of input / output devices provided in the station 100. That is, the user interface unit 140 can receive user input by using various input devices, and the processor 110 can control the station 100 based on the received user input. In addition, the user interface unit 140 can perform output based on the command of the processor 110 by using various output devices.

[0062] Next, the display unit 150 outputs an image on the display screen. The display unit 150 can output various display objects, such as content executed by the processor 110 or a user interface, based on the control command of the processor 110. In addition, the memory 160 stores control programs used in the station 100 and various result data. The control program may include an access program required for the station 100 to access the AP or an external station.

[0063] The processor 110 of the present invention can execute various commands or programs and process data within the station 100. Furthermore, the processor 110 can control various units of the station 100 and control data transmission / reception within the units. According to an embodiment of the present invention, the processor 110 can execute a program for accessing an AP stored in the memory 160 and receive a communication configuration message sent by the AP. Furthermore, the processor 110 can read information regarding the priority conditions of the station 100 included in the communication configuration message and request access to the AP based on the information regarding the priority conditions of the station 100. The processor 110 of the present invention can represent the main control unit of the station 100. Depending on the embodiment, the processor 110 can also represent a control unit for individually controlling certain components of the station 100, such as the communication unit 120. Specifically, the processor 110 can be a modem or modulator / demodulator for modulating wireless signals transmitted to the communication unit 120 and demodulating wireless signals received from the communication unit 120. According to an embodiment of the present invention, the processor 110 controls various operations of wireless signal transmission / reception within the station 100. Detailed embodiments of this control are described below.

[0064] exist Figure 3 The station 100 shown in FIG. 1 is a block diagram according to one embodiment of the present invention, where individual blocks are illustrated as components of a logically distinct device. Therefore, the components of the device may be implemented in a single chip or multiple chips, depending on the design of the device. For example, the processor 110 and the communication unit 120 may be implemented as an integrated single chip or as separate chips. Furthermore, in embodiments of the present invention, certain 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.

[0065] Figure 4 is a block diagram illustrating the configuration of an AP 200 according to one embodiment of the present invention. Figure 4 As shown in FIG, the AP 200 according to an embodiment of the present invention may include a processor 210, a communication unit 220, and a memory 260. Figure 4 Among the components of AP200, Figure 2 The components of station 100 are the same as or correspond to Figure 2 Repeated description of parts of the components of the station 100 will be omitted.

[0066] refer to Figure 4 , the AP 200 according to the present invention includes a communication unit 220 that operates a BSS in at least one frequency band. Figure 3As described in the embodiment of the present invention, the communication unit 220 of the AP 200 may also include multiple 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 in different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. Preferably, the AP 200 may include a communication module using a frequency band of 6 GHz or above, and a communication module using a frequency band of 6 GHz or below. Each communication module may perform wireless communication with a station according to the wireless LAN standard of the frequency band supported by the corresponding communication module. The communication unit 220 may operate only one communication module at a time, or operate multiple communication modules simultaneously, depending on the performance and requirements of the AP 200. In the embodiment of the present invention, the communication unit 220 may represent a radio frequency (RF) communication module for processing RF signals.

[0067] Next, the memory 260 stores control programs used by the AP 200 and various result data. The control programs may include access programs for managing station access. Furthermore, the processor 210 may control various units of the AP 200 and control data transmission / reception within the units. According to an embodiment of the present invention, the processor 210 may execute programs for accessing stations stored in the memory 260 and send communication configuration messages for one or more stations. In this case, the communication configuration message may include information regarding access priority conditions for each station. Furthermore, the processor 210 performs access configuration based on access requests from stations. According to one embodiment, the processor 210 may be a modem or modulator / demodulator for modulating wireless signals transmitted to the communication unit 220 and demodulating wireless signals received from the communication unit 220. According to an embodiment of the present invention, the processor 210 controls various operations, such as wireless signal transmission / reception of the AP 200. A detailed embodiment of this will be described below.

[0068] Figure 5 is a diagram schematically illustrating a process in which a STA sets up a link with an AP.

[0069] refer to Figure 5 In a broad sense, a link between STA 100 and AP 200 is established via three steps: scanning, authentication, and association. First, the scanning step is a step in which STA 100 obtains access information of a BSS operated by AP 200. Methods for performing scanning include a passive scanning method in which AP 200 obtains information by using a beacon message transmitted periodically (S101), and an active scanning method in which STA 100 transmits a probe request to AP (S103) and obtains access information by receiving a probe response from AP (S105).

[0070] STA 100, which has successfully received wireless access information in the scanning step, performs an authentication step (S107b) by sending an authentication request (S107a) and receiving an authentication response from AP 200. After performing the authentication step, STA 100 performs an association step by sending an association request (S109a) and receiving an association response (S109b) from AP 200. In this specification, association generally refers to wireless association, but the present invention is not limited thereto, and association can broadly include both wireless association and wired association.

[0071] At the same time, an authentication step (S111) based on 802.1X and an IP address acquisition step (S113) via DHCP may be additionally performed. Figure 5 In FIG, the authentication server 300 is a server that processes 802.1X-based authentication for the STA 100 and may exist in physical association with the AP 200 or as a separate server.

[0072] Figure 6 The diagram illustrates a carrier sense multiple access (CSMA) / collision avoidance (CA) method used in wireless LAN communications.

[0073] A terminal performing wireless LAN communication checks whether a channel is busy by performing carrier sensing before sending data. When a wireless signal with a predetermined strength or above is sensed, the corresponding channel is determined to be busy, and the terminal delays access to the corresponding channel. Such a process is called clear channel assessment (CCA), and the level for determining whether the corresponding signal is sensed is called the CCA threshold. When a wireless signal with a CCA threshold or above received by a terminal indicates that the corresponding terminal is a receiver, the terminal processes the received radio signal. At the same time, when no wireless signal is sensed in the corresponding channel, or when a wireless signal with a strength less than the CCA threshold is sensed, the channel is determined to be idle.

[0074] When a channel is determined to be idle, each terminal with data to transmit performs a backoff procedure after an interframe space (IFS) period, such as arbitration IFS (AIFS), PCF IFS (PIFS), or the like, has elapsed, depending on the situation of each terminal. According to this embodiment, AIFS can be used as a component to replace the existing DCF IFS (DIFS). By determining a random number during an idle period in a channel, each terminal prepares for a decrease in slot time, and a terminal that has fully used up that slot attempts to access the corresponding channel. Therefore, the interval during which each terminal performs the backoff procedure is called a contention window interval.

[0075] When a specific terminal successfully accesses the channel, the corresponding terminal can send data via the channel. However, when the terminal attempting access conflicts with another terminal, the conflicting terminals are assigned new random numbers to respectively perform the backoff process again. According to one embodiment, it can be determined that the random number reassigned to each terminal is within a range (2*CW), which is twice the range (contention window, CW) of the random number previously used by the corresponding terminal. At the same time, each terminal attempts access by performing the backoff process again in the next contention window interval, and in this case, each terminal performs the backoff process starting from the time slot time maintained in the previous contention window interval. By such a method, each terminal performing wireless LAN communication can avoid conflict with each other for a specific channel.

[0076] Multi-user transmission

[0077] When using Orthogonal Frequency Division Multiple Access (OFDMA) or Multiple Input Multiple Output (MIMO), one wireless communication terminal can simultaneously transmit data to multiple wireless communication terminals. In addition, one wireless communication terminal can simultaneously receive data from multiple wireless communication terminals. For example, downlink multi-user (DL-MU) transmission, in which an AP simultaneously transmits data to multiple STAs, and uplink multi-user (UL-MU) transmission, in which multiple STAs simultaneously transmit data to an AP, can be performed.

[0078] In order to perform UL-MU transmission, the channel to be used and the transmission start time of each STA performing uplink transmission should be adjusted. According to an embodiment of the present invention, the UL-MU transmission process can be managed by the AP. UL-MU transmission can be performed in response to a trigger frame sent by the AP. The trigger frame indicates the UL-MU transmission of at least one STA. After receiving the trigger frame, the STA simultaneously sends uplink data at a predetermined IFS time. The trigger frame can indicate the data transmission time point of the uplink transmission STA and can notify the channel (or subchannel) information allocated to the uplink transmission STA. When the AP sends a trigger frame, multiple STAs send uplink data through each allocated subcarrier at the time specified by the trigger frame. After completing the uplink data transmission, the AP sends an ACK to the STA that has successfully sent the uplink data. In this case, the AP can send a predetermined multi-STA block ACK (M-BA) as an ACK for multiple STAs.

[0079] In non-legacy wireless LAN systems, a specific number of tones, such as 26, 52, or 106, can be used as resource units (RUs) for sub-channel-based access in a channel in the 20 MHz band. Therefore, the trigger frame can indicate the identification information of each STA participating in the UL-MU transmission and the information of the allocated resource units. The STA identification information includes at least one of the STA's association ID (AID), partial AID, and MAC address. In addition, the resource unit information includes the size and layout information of the resource unit.

[0080] Spatial reuse operations

[0081] Figure 7 The figure illustrates a channel access method using spatial reuse (SR) operation according to an embodiment of the present invention. Due to the popularity of mobile devices and the popularity of wireless communication systems, terminals are increasingly communicating in dense environments. Specifically, the number of situations in which terminals communicate in an environment where multiple BSSs overlap is increasing. When multiple BSSs overlap, the communication efficiency of the terminal may decrease due to interference with other terminals. In particular, if the frequency band is used through a contention process, the terminal may not even be able to secure a transmission opportunity due to interference with other terminals. To solve this problem, the terminal can perform an SR operation.

[0082] More specifically, the terminal can determine whether the frame is an intra-BSS frame or an inter-BSS frame based on the information for identifying the BSS of the received frame. The information for identifying the BSS includes at least one of a BSS color, a partial BSS color, a partial AID, or a MAC address. In an embodiment of the present invention, a non-traditional terminal may refer to a terminal that complies with the next-generation wireless LAN standard (ie, IEEE802.11ax). In addition, an intra-BSS frame indicates a frame sent from a terminal belonging to the same BSS, and an inter-BSS frame indicates a frame sent from a terminal belonging to an overlapping BSS (OBSS) or another BSS.

[0083] According to an embodiment of the present invention, a non-legacy terminal may perform different operations depending on whether the received frame is an intra-BSS frame. That is, when the received frame is determined to be an intra-BSS frame, the terminal may perform a first operation. In addition, when the received frame is determined to be an inter-BSS frame, the terminal may perform a second operation different from the first operation. According to an embodiment, the second operation performed by the terminal when the received frame is determined to be an inter-BSS frame may be an SR operation. According to an embodiment of the present invention, the first operation and the second operation may be set in various ways.

[0084] According to an embodiment, the terminal may perform channel access based on different thresholds depending on whether the received frame is an intra-BSS frame. More specifically, when the received frame is determined to be an intra-BSS frame, the terminal accesses the channel based on a first CCA threshold (i.e., a first operation). That is, the terminal performs CCA based on the first CCA threshold, and determines whether the channel is busy based on the result of performing the CCA. On the other hand, when the received frame is determined to be an inter-BSS frame, the terminal may access the channel based on a second CCA threshold (i.e., a second operation or an SR operation), which is different from the first CCA threshold. That is, the terminal determines whether the channel is busy based on both the first CCA threshold and the second CCA threshold. According to an embodiment of the present invention, the second CCA threshold is an OBSS PD level set to determine whether the channel is busy based on the received signal strength of the inter-BSS frame. In this case, the second CCA threshold may have a value equal to or greater than the first CCA threshold.

[0085] According to another embodiment of the present invention, the terminal may adjust the transmission power of the PHY protocol data unit (PPDU) sent by the terminal according to whether the received frame is an intra-BSS frame. More specifically, when the received frame is determined to be an inter-BSS frame, the terminal may adjust the transmission power of the PPDU based on the SR parameter extracted from the received frame (i.e., the second operation or SR operation). According to an embodiment, the terminal may increase the transmission power based on the SR parameter extracted from the received frame. According to an embodiment of the present invention, a non-traditional frame may include an SR field for an SR operation of an OBSS terminal, and a specific embodiment thereof will be described later. On the other hand, when the received frame is determined to be an intra-BSS frame, the terminal does not perform transmission power adjustment based on the SR parameter.

[0086] refer to Figure 7 , the transmitted non-legacy frames 310 and 320 may include information indicating whether an SR operation is allowed for the corresponding PPDU (i.e., information indicating whether SR is allowed). According to an embodiment, the information indicating whether SR is allowed may be represented by a predetermined index of the SR field. For example, if the value of the SR field is 0 (i.e., if all bit values ​​of the SR field are 0), it may indicate that the SR operation is not allowed. Figure 7 In the embodiment, the information indicating whether SR is allowed included in the received first frame 310 indicates that the SR operation for the corresponding PPDU is allowed. In addition, the information indicating whether SR is allowed included in the received second frame 320 indicates that the SR operation for the corresponding PPDU is not allowed. In this case, it is assumed that both the received first frame 310 and the received second frame 320 are inter-BSS frames.

[0087] The terminal receiving the first frame 310 determines whether the received frame 310 is an intra-BSS frame or an inter-BSS frame. Furthermore, the terminal checks information indicating whether SR is permitted in the received frame 310. In this case, the received frame 310 is determined to be an inter-BSS frame, and the information indicating whether SR is permitted indicates that SR operation is permitted for the corresponding PPDU. Therefore, the terminal can perform SR operation according to the above-described embodiment. That is, the terminal can determine whether the channel is busy based on the first and second CCA thresholds. Furthermore, the terminal can adjust the transmission power based on the SR parameters extracted from the received frame 310.

[0088] At the same time, the terminal receiving the second frame 320 determines whether the received frame 320 is an intra-BSS frame or an inter-BSS frame. Furthermore, the terminal checks the information indicating whether SR is permitted in the received frame 320. In this case, the received frame 320 is determined to be an inter-BSS frame, and the information indicating whether SR is permitted indicates that SR operation is not permitted for the corresponding PPDU. Therefore, the terminal does not perform SR operation according to the above-described embodiment. That is, although the received frame 320 is determined to be an inter-BSS frame, the terminal accesses the channel based on the first CCA threshold. Furthermore, the terminal does not perform transmission power adjustment based on the SR parameters extracted from the received frame 320.

[0089] According to another embodiment of the present invention, information indicating whether SR is allowed can be transmitted via a legacy format frame. By including information indicating whether SR is allowed in a legacy format frame, the AP can protect the transmitted legacy frame from SR operations by non-legacy terminals. According to an embodiment, the information indicating whether SR is allowed can be transmitted via the L preamble. For example, a reserved bit of the L-SIG of the L preamble can indicate whether SR is allowed. Alternatively, the guard subcarrier of the L-SIG of the L preamble can carry the information indicating whether SR is allowed.

[0090] According to another embodiment, information indicating whether SR is allowed may be transmitted via the VHT preamble. For example, a reserved bit of the VHT-SIG-A1 or VHT-SIG-A2 of the VHT preamble may indicate whether SR is allowed. Alternatively, a guard subcarrier of the VHT-SIG-A1 or VHT-SIG-A2 of the VHT preamble may carry information indicating whether SR is allowed. According to yet another embodiment, information indicating whether SR is allowed may be transmitted via the HT preamble. For example, a reserved bit of the HT preamble may indicate whether SR is allowed. Alternatively, a guard subcarrier of the HT preamble may carry information indicating whether SR is allowed. According to yet another embodiment of the present invention, information indicating whether SR is allowed may be transmitted via the MAC header.

[0091] Figure 8FIG2 illustrates the SR operation of a terminal according to an embodiment of the present invention when a PPDU including a trigger frame is transmitted in an OBSS. Figure 8 In the embodiment of FIG, BSS1 includes STA1 and STA2. In this case, STA1 is a non-AP STA and STA2 is an AP. In addition, BSS2 includes STA3 and STA4. In this case, STA3 is a non-AP STA and STA4 is an AP. Figure 8 In the embodiment of the present invention, STA2 sends a trigger frame (or a PPDU containing a trigger frame) to STA1, and STA1 transmits an uplink PPDU in response. The uplink PPDU transmitted by STA1 may be a triggered PPDU. At the same time, STA3 of BSS2 intends to transmit a PPDU to STA4. Before transmitting the PPDU, STA3 may receive the trigger frame transmitted by STA2 and / or the triggered PPDU transmitted by STA1. In this case, STA3 may obtain SR parameters from at least one of the trigger frame and the corresponding triggered PPDU.

[0092] According to an embodiment of the present invention, when sending a trigger frame, the AP may signal at least one of the AP's acceptable interference level and the transmission power of the PPDU containing the trigger frame. More specifically, the AP may include a SR parameter (hereinafter referred to as SRP) in the trigger frame. According to an embodiment of the present invention, the SRP may be configured as follows.

[0093] [Equation 1]

[0094] SRP = TXPWR_AP + Acceptable Receiver Interference Level_AP

[0095] Here, "TXPWR_AP" represents the transmission power of the PPDU containing the trigger frame. Furthermore, "Acceptable Receiver Interference Level_AP" represents the interference level that the AP transmitting the trigger frame can tolerate, i.e., the acceptable interference level. The acceptable interference level may indicate the interference level that the AP can tolerate when receiving a trigger-based PPDU in response to the trigger frame transmitted by the AP. Thus, the SRP may be determined based on the transmission power of the PPDU containing the trigger frame and the acceptable interference level. More specifically, the SRP may be set to the sum of the transmission power of the PPDU containing the trigger frame and the acceptable interference level.

[0096] According to an embodiment of the present invention, the AP may transmit the SRP determined by Equation 1 by inserting it into a trigger frame. According to an embodiment, the SRP may be included in the common information field of the trigger frame. The STA that receives the trigger frame from the AP transmits a multi-user uplink frame, i.e., a triggered PPDU in response thereto. In this case, the STA may carry the SRP information obtained from the trigger frame via a predetermined field of the triggered PPDU. According to an embodiment, the SRP information may be included in the SR field of the HE-SIG-A of the triggered PPDU.

[0097] Meanwhile, a terminal receiving a trigger frame sent from an OBSS may perform an SR operation based on the obtained SRP. In this case, the SRP may be obtained from at least one of the trigger frame and the corresponding trigger-based PPDU. According to an embodiment, the terminal may adjust the transmission power of the PPDU based on the SRP as follows.

[0098] [Equation 2]

[0099] TXPWR_STA <SRP-RSSI_TriggerFrame_at_STA

[0100] Here, "TXPWR_STA" represents the transmission power of the PPDU to be sent by the terminal. In addition, "RSSI_TriggerFrame_at_STA" represents the received signal strength of the PPDU containing the trigger frame measured by the terminal. That is, the transmission power of the terminal is set to be lower than the value obtained by subtracting the received signal strength of the PPDU containing the trigger frame from the obtained SRP value. According to an embodiment of the present invention, the terminal can send the PPDU with the transmission power "TXPWR_STA" set according to Equation 2. Alternatively, the terminal can send the PPDU only when the expected transmission power "TXPWR_STA" of the terminal is less than the value obtained by subtracting the received signal strength of the PPDU containing the trigger frame from the obtained SRP value, as in Equation 2.

[0101] according to Figure 8 In an embodiment of the present invention, STA2 transmits an SRP by inserting the SRP into a trigger frame. In addition, STA1 transmits a trigger-based PPDU in response to the received trigger frame. In this case, STA1 may insert the SRP into a predetermined field of the trigger-based PPDU. STA3 measures the received signal strength of the PPDU containing the trigger frame transmitted by STA2. In addition, STA3 may obtain the SRP from at least one of the trigger frame transmitted by STA2 and the trigger-based PPDU transmitted by STA1. According to an embodiment of the present invention, when the transmission power value of the PPDU to be transmitted by STA3 to STA4 is lower than the transmission power determined by Equation 2, STA3 may transmit the PPDU to STA4.

[0102] The magnitude of the transmission power and interference can be values ​​normalized to a 20 MHz frequency bandwidth. For example, TXPWR = power - 10 * log (BW / 20 MHz). In this case, BW represents the total transmission bandwidth. Therefore, SRP can be a normalized value within a 20 MHz frequency bandwidth. Therefore, the terminal can scale the transmission power value of the PPDU to be transmitted according to the frequency bandwidth used by the PPDU to be transmitted to apply the above equation.

[0103] When a terminal receives a radio signal, it can process the received signal separately in the physical layer and the MAC layer. In this case, the interface between the physical layer and the MAC layer is called a primitive. Furthermore, operations of the terminal's physical layer can be performed by the PHY layer management entity (PLME). Furthermore, operations of the terminal's MAC layer can be performed by the MAC layer management entity (MLME). In this case, for the above-mentioned embodiment, the RXVECTOR of the primitive can include at least one of the SRP (or SR field value), the transmission opportunity (TXOP) duration, or the BSS color.

[0104] Figure 9 The SR operation of the terminal according to an embodiment of the present invention when the PPDU containing the trigger frame is transmitted in the OBSS is illustrated in more detail. Figure 8 As described above, the terminal may transmit the PPDU according to the SR operation based on the received signal strength of the PPDU including the trigger frame transmitted from the OBSS and the obtained SRP value. Specifically, the terminal may transmit the PPDU by adjusting the transmission power based on the received signal strength of the PPDU including the trigger frame transmitted from the OBSS and the SRP value indicated by the trigger frame and / or the triggered PPDU.

[0105] More specifically, the terminal can adjust the transmission power of the PPDU to be sent to satisfy Equation 2 as described above. In this case, the terminal can access the channel and send the PPDU by adjusting the transmission power when obtaining the SRP value. According to another embodiment, the terminal can start the transmission of the PPDU by adjusting the transmission power at the end of the transmission of the PPDU containing the trigger frame sent from the OBSS. However, when the PPDU containing the trigger frame is a traditional PPDU, the terminal can decode the MAC frame of the corresponding PPDU to determine whether the PPDU contains a trigger frame. In addition, if the BSS indicated by the signaling field of the PPDU is different from the BSS indicated by the address field of the MAC header, the terminal can decode the MAC frame of the corresponding PPDU. At this time, the terminal can obtain the SRP value from the trigger frame.

[0106] exist Figure 9In the embodiment of FIG. 1 , the terminal is shown to transmit the PPDU by adjusting the transmission power at the end of the transmission of the PPDU including the trigger frame transmitted from the OBSS. According to another specific embodiment, when the PPDU including the trigger frame is a conventional PPDU, the terminal can transmit the PPDU by adjusting the transmission power when the terminal checks that the PPDU is a trigger frame transmitted from the OBSS. In these embodiments, the terminal can transmit the PPDU at a time when the terminal is compared with the reference frame. Figure 8 The described embodiment transmits the PPDU based on the SR operation at an earlier point in time.

[0107] Figure 10 This figure illustrates an embodiment in which a terminal performs an SR operation based on a contention procedure when transmitting a PPDU containing a trigger frame in an OBSS. As described above, during the transmission of a corresponding trigger-based PPDU and trigger frame in the OBSS, the terminal can transmit the PPDU based on the SR operation. Specifically, the terminal can transmit the PPDU according to the conditions of Equation 2. That is, the terminal can transmit the PPDU by adjusting the transmission power according to Equation 2.

[0108] At the same time, one or more terminals can transmit PPDUs based on SR operations during the transmission process in the OBSS. However, when multiple terminals transmit PPDUs based on SR operations, conflicts may occur between transmissions from different terminals. In addition, when multiple terminals transmit PPDUs, interference exceeding the interference amplitude that the OBSS access point can tolerate may occur.

[0109] exist Figure 10 In the embodiment of FIG, BSS1 includes STA1 and STA2. In this case, STA1 is a non-AP STA, and STA2 is an AP. In addition, BSS2 includes STA3, STA4, and STA5. In this case, STA3 is a non-AP STA, STA4 is an AP, and STA5 is a non-AP STA. In addition, BSS3 includes STA6, and STA6 is a non-AP STA. Figure 10 In the embodiment of FIG, STA2 sends a trigger frame (or a PPDU containing a trigger frame) to STA1, and STA1 sends an uplink PPDU in response thereto. The uplink PPDU sent by STA1 may be a triggered PPDU.

[0110] exist Figure 10 In this embodiment, when at least two of STA3 to STA6 transmit PPDUs simultaneously, a collision may occur. Furthermore, when at least two of STA3 to STA6 transmit PPDUs simultaneously, interference exceeding the interference tolerance of STA2 may occur. Consequently, STA2 may not be able to receive the PPDU from STA1. To address this issue, when performing PPDU transmission based on SR operation, the terminal can perform a backoff procedure to access the channel.

[0111] refer to Figure 10 , if a PPDU is sent based on an SR operation, the terminal may perform the above-mentioned backoff process. In this case, the terminal may use the backoff counter used when accessing the channel through DCF and EDCAF as the backoff counter value of the corresponding backoff process. According to an embodiment of the present invention, in order to determine whether the channel is idle during the backoff process, the terminal may use energy detection (ED). According to another embodiment of the present invention, the terminal may determine whether the channel is idle based on whether a PPDU with a signal strength higher than a threshold is received. In this case, the threshold may be a value greater than the existing minimum receiving sensitivity. For example, the terminal may determine whether the channel is idle based on the above-mentioned OBSS PD level. According to an embodiment of the present invention, the OBSS PD level used by the terminal in the SR operation may be set to a large value without any restrictions. For example, the OBSS PD level used in the SR operation may be set to a predetermined value lower than an infinite value. During the transmission of a triggered PPDU of OBSS, the terminal may perform the SR operation using the set OBSS PD level.

[0112] Figure 11 This figure illustrates an embodiment of a terminal's operation of setting the NAV when a PPDU containing a trigger frame is transmitted in an OBSS. If a PPDU containing a trigger frame is transmitted in an OBSS and the terminal is capable of transmitting the PPDU based on a SR operation, the terminal may not set the NAV based on the trigger frame (or the PPDU containing the trigger frame). Furthermore, if the terminal fails to receive a PPDU containing a trigger frame transmitted from the OBSS, the terminal cannot set the NAV based on the trigger frame.

[0113] When the terminal receives a triggered PPDU sent from the OBSS, the terminal is able to send the PPDU based on the SR operation, as in the above-mentioned embodiment. However, if the condition for sending the PPDU based on the SR operation is not met, the terminal may set the NAV based on the signaling field of the triggered PPDU. In this case, the signaling field may be the TXOP duration field of the HE-SIG-A field. If the condition for sending the PPDU based on the SR operation is not met, the terminal may perform CCA during the transmission of the triggered PPDU in the OBSS by using a value less than or equal to the first CCA threshold instead of the OBSS PD level (i.e., the second CCA) set above. This is because the PPDU transmission based on the SR operation of the terminal can generate interference of a magnitude greater than that of the interference that can be tolerated by the AP of the OBSS that will receive the triggered PPDU. At the same time, in Figure 11 In the embodiment of FIG, STA2 receives the legacy preamble of the triggered PPDU sent in the OBSS, but may not be able to receive the non-legacy signaling field. In this case, STA2 may perform CCA based on the minimum receive sensitivity.

[0114] According to another embodiment of the present invention, if the information used to determine whether the conditions for transmitting a PPDU based on an SR operation are met is insufficient, the terminal may not perform PPDU transmission based on the SR operation. In this case, the terminal may perform CCA during the transmission of the triggered PPDU in the OBSS by using the first CCA threshold instead of the OBSS PD level (i.e., the second CCA threshold). In this case, the case where the information used to determine whether the conditions for transmitting a PPDU based on an SR operation are met is insufficient includes the case where the terminal fails to receive a trigger frame.

[0115] Figure 12 The figure shows an embodiment of sending spatial reuse parameters via a trigger frame and a corresponding trigger-based PPDU. Figure 12 In an embodiment of the present invention, the AP sends a trigger frame (or a PPDU containing a trigger frame), and the receiving STA sends a PPDU based on the trigger.

[0116] As described above, the AP can transmit the SRP determined by Equation 1 by inserting it into a trigger frame. According to an embodiment, the SRP may be included in the common information field of the trigger frame. The STA that receives the trigger frame from the AP transmits a triggered PPDU in response. In this case, the STA may carry the SRP information obtained from the trigger frame via a predetermined field of the triggered PPDU. According to an embodiment, the SRP information may be included in the SR field of the HE-SIG-A of the triggered PPDU. That is, the SR field of the triggered PPDU may carry the SRP obtained from the trigger frame.

[0117] According to an embodiment of the present invention, the HE-SIG-A of the triggered PPDU may contain multiple SR fields. The multiple SR fields carry the SRP obtained from the trigger frame. In this case, each of the multiple SR fields indicates the SRP of a single subband constituting the total bandwidth over which the triggered PPDU is transmitted. The total bandwidth over which the triggered PPDU is transmitted may be indicated by the bandwidth field of the HE-SIG-A of the triggered PPDU. Figure 12 , the HE-SIG-A of the triggered PPDU may include N SR fields. Each of the N SR fields may indicate the SRP of a single subband in units of 20 MHz or 40 MHz. According to an embodiment of the present invention, N may be set to 4. That is, the multiple SR fields may include a first SR field, a second SR field, a third SR field, and a fourth SR field. However, the present invention is not limited thereto. According to an embodiment, the multiple SR fields may respectively indicate the SRP for different subbands. However, according to an embodiment of the present invention, under certain conditions, at least some of the multiple SR fields may be set to have the same value. Specific embodiments will be described later.

[0118] The HE-SIG-A of the HE-format PPDU signals the same information in units of 20 MHz bandwidth. That is, the multiple SR fields of the HE-SIG-A can be replicated in units of 20 MHz bandwidth and can be carried by the total bandwidth in which the triggered PPDU is transmitted. Therefore, a terminal receiving the triggered PPDU can detect N SR fields corresponding to each subband.

[0119] The physical frequency band on which a triggered PPDU is transmitted can be identified using various information or a combination thereof. According to an embodiment, the physical frequency band on which a triggered PPDU is transmitted can be identified based on bandwidth field information and operating class information. The bandwidth field of the HE-SIG-A of a triggered PPDU indicates the total bandwidth over which the triggered PPDU is transmitted. Furthermore, the operating class information may include information regarding which frequency bands a specific frequency band can be combined with to configure a wideband channel. Therefore, a terminal receiving a triggered PPDU can identify the order in which subbands in the total bandwidth are to be received for the corresponding PPDU based on the bandwidth field information and operating class information extracted from the received PPDU. Furthermore, a terminal receiving a triggered PPDU can identify the SR field, among multiple SR fields, used to receive the corresponding PPDU, based on the bandwidth field information and operating class information. While the above describes a method for identifying the physical frequency band on which a triggered PPDU is transmitted, the physical frequency band on which a HE format PPDU is transmitted can also be identified in the same manner.

[0120] According to another embodiment of the present invention, a HE-formatted PPDU may separately signal the physical band information on which the corresponding PPDU is transmitted. For example, the HE-SIG-A of the HE PPDU may include the physical band information on which the PPDU is transmitted. More specifically, the HE-SIG-A may indicate one or more frequency information on which the physical band information on which the corresponding PPDU is transmitted is transmitted. For example, the HE-SIG-A may indicate the starting frequency index of the frequency band on which the PPDU is transmitted. In addition, when the total bandwidth on which the PPDU is transmitted is 80+80 MHz or 160 MHz, the HE-SIG-A may indicate at least two frequency indices. According to yet another embodiment of the present invention, a PPDU in the HE format may signal the center frequency information on which the corresponding PPDU is transmitted. In addition, when the total bandwidth on which the PPDU is transmitted is 80+80 MHz or 160 MHz, information on at least two center frequencies of the physical band on which the PPDU is transmitted may be signaled.

[0121] According to an embodiment of the present invention, a triggered PPDU can signal channel information corresponding to each of the multiple SR fields of the HE-SIG-A. In this case, the channel information includes information regarding at least one of the channel number, the channel frequency, and the channel center frequency. The signaled channel information can be sequentially matched with the multiple SR fields. If the total bandwidth for transmitting the triggered PPDU is 80+80 MHz or 160 MHz, the total bandwidth can be divided into a first frequency band and a second frequency band in units of 80 MHz. According to an embodiment of the present invention, the triggered PPDU can signal channel information corresponding to the SR fields of the first frequency band and the second frequency band, respectively. According to another embodiment, the triggered PPDU can signal channel information corresponding to the SR field of the first frequency band or the second frequency band. In this case, only the channel information corresponding to the SR field of the first frequency band or the second frequency band can be explicitly indicated. A terminal receiving the triggered PPDU can identify the SR field of the frequency band in which the PPDU is received, among the multiple SR fields, based on whether the frequency band in which the corresponding PPDU is received is a frequency band that explicitly indicates channel information.

[0122] According to an embodiment of the present invention, the SR field can be adjusted based on the total bandwidth over which the trigger-based PPDU is transmitted. According to an embodiment, when the total bandwidth indicated by the bandwidth field exceeds a predetermined bandwidth, the number of multiple SR fields included in the HE-SIG-A can be increased. According to another embodiment, when the total bandwidth indicated by the bandwidth field exceeds a predetermined bandwidth, the frequency bandwidth corresponding to each SR field can be increased. More specifically, when the total bandwidth indicated by the bandwidth field is less than or equal to the predetermined bandwidth, the SR field may indicate the SRP of a subband of a first frequency bandwidth. However, when the total bandwidth indicated by the bandwidth field exceeds the predetermined bandwidth, the SR field may indicate the SRP of a subband of a second frequency bandwidth wider than the first frequency bandwidth. For example, when the total bandwidth indicated by the bandwidth field is 20 MHz, 40 MHz, or 80 MHz, the SR field may indicate the SRP of a subband of a 20 MHz bandwidth. However, when the total bandwidth indicated by the bandwidth field is 80+80 MHz or 160 MHz, the SR field may indicate the SRP of a subband of a 40 MHz bandwidth.

[0123] Figure 13 FIG2 illustrates a method for signaling a spatial reuse field of a trigger-based PPDU according to an embodiment of the present invention. Figure 13The HE-SIG-A of a triggered PPDU may include multiple SR fields. According to an embodiment of the present invention, the HE-SIG-A of a triggered PPDU may include four SR fields. That is, the HE-SIG-A includes a first SR field, a second SR field, a third SR field, and a fourth SR field. Moreover, each SR field may consist of 4 bits. Each SR field may indicate the SRP of a single subband in units of 20 MHz or 40 MHz.

[0124] First, when the total bandwidth for transmitting the trigger-based PPDU is 20 MHz, the first SR field indicates the SRP of the corresponding 20 MHz band. In addition, the second SR field, the third SR field, and the fourth SR field are set to the same value as the first SR field.

[0125] Next, when the total bandwidth for transmitting trigger-based PPDUs is 40 MHz, the first SR field indicates the SRP of the first 20 MHz band, and the second SR field indicates the SRP of the second 20 MHz band. In addition, the third SR field is set to the same value as the first SR field, and the fourth SR field is set to the same value as the second SR field. In this case, the first 20 MHz band and the second 20 MHz band constitute a total bandwidth of 40 MHz, over which the trigger-based PPDU is transmitted.

[0126] Next, when the total bandwidth for transmitting the trigger-based PPDU is 80 MHz, the first SR field indicates the SRP of the first 20 MHz frequency band, the second SR field indicates the SRP of the second 20 MHz frequency band, the third SR field indicates the SRP of the third 20 MHz frequency band, and the fourth SR field indicates the SRP of the fourth 20 MHz frequency band. In this case, the first 20 MHz frequency band to the fourth 20 MHz frequency band constitute a total bandwidth of 80 MHz, over which the trigger-based PPDU is transmitted.

[0127] Meanwhile, when the total bandwidth for transmitting the trigger-based PPDU is 160 MHz, the first SR field indicates the SRP of the first 40 MHz band, the second SR field indicates the SRP of the second 40 MHz band, the third SR field indicates the SRP of the third 40 MHz band, and the fourth SR field indicates the SRP for the fourth 40 MHz band. In this case, the first 40 MHz band to the fourth 40 MHz band constitute the total bandwidth of 160 MHz for transmitting the trigger-based PPDU.

[0128] According to an embodiment of the present invention, multiple SR fields may indicate the SRP of multiple subbands in physical frequency order. According to an embodiment, multiple SR fields may indicate the SRP of multiple subbands in ascending order of physical frequency. That is, the first SR field may indicate the SRP of the lowest frequency subband, and the fourth SR field may indicate the SRP of the highest frequency subband. According to another embodiment, multiple SR fields may indicate the SRP of multiple subbands in descending order of physical frequency. That is, the first SR field may indicate the SRP of the highest frequency subband, and the fourth SR field may indicate the SRP of the lowest frequency subband.

[0129] Figure 14 The figure illustrates an embodiment of a method for setting the spatial reuse field of a triggered PPDU. As described above, when the total bandwidth for transmitting the triggered PPDU is 160 MHz (or 80+80 MHz), each SR field of the triggered PPDU can indicate the SRP of a single subband in units of 40 MHz. Therefore, a method for setting the SRP of each subband in units of 40 MHz is required.

[0130] according to Figure 14 In an embodiment of the present invention, the SR field x of the xth 40MHz band can be determined by reflecting the SRP of the 20MHz channel xa and the SRP of the 20MHz channel xb (where x=1, 2, 3, or 4). If the SR field indicates the SRP of the subband in units of 40MHz, the resolution of the information of each subband is reduced. For example, if the SR field x is determined by normalizing the SRP of the channel xa and the SRP of the channel xb, and the conditions of the channel xa and the channel xb are different, interference exceeding the acceptable interference level may occur at the channel with the worst condition among the two channels. Therefore, according to an embodiment of the present invention, the SR field of the 40MHz band can be determined based on a conservative value among the SRPs of the 20MHz sub-bands constituting the corresponding band.

[0131] According to an embodiment of the present invention, the SR field x of the x-th 40 MHz frequency band may be determined as shown in Equation 3.

[0132] [Equation 3]

[0133] SRP_x=2*min(SRP_xa,SRP_xb)

[0134] in

[0135] SRP_xa=TX PWR_AP,xa+Acceptable Receiver Interference Level_AP,xa

[0136] SRP_xb=TX PWR_AP,xb+Acceptable Receiver Interference Level_AP,xb

[0137] Here, "SRP_x" represents the value of the SR field x, that is, the xth SRP. In addition, "SRP_xa" and "SRP_xb" represent the SRPs of the first 20 MHz band and the second 20 MHz band, respectively, which constitute the xth 40 MHz band. "SRP_xa" can be set to the sum of the transmission power "TX PWR_AP,xa" of the PPDU containing the trigger frame on channel xa and the acceptable interference level "Acceptable Receiver Interference Level_AP,xa" in channel xa. Moreover, "SRP_xb" can be set to the sum of the transmission power "TX PWR_AP,xb" of the PPDU containing the trigger frame on channel xb and the acceptable interference level "Acceptable Receiver Interference Level_AP,xb" in channel xb. That is, according to an embodiment of Equation 3, the SR field x can be set to twice the minimum value of "SRP_xa" and "SRP_xb" for the corresponding 20 MHz band.

[0138] According to another embodiment of the present invention, the SR field x of the x-th 40 MHz frequency band may be determined as shown in Equation 4.

[0139] [Equation 4]

[0140] SRP_x = TX PWR_AP,x + Acceptable Receiver Interference Level_AP,x

[0141] in

[0142] TX PWR_AP, x=2*min (TX PWR_AP, xa, TX PWR_AP, xb)

[0143] Acceptable receiver interference level_AP,x=2*min(Acceptable receiver interference level_AP,xa,Acceptable receiver interference level_AP,xb)

[0144] Referring to Equation 4, "SRP_x" can be set to the sum of the transmit power "TXPWR_AP,x" of the PPDU containing the trigger frame in channel x and the tolerable interference level "Acceptable Receiver Interference Level_AP,x." In this case, "TXPWR_AP,x" can be set to twice the minimum of "TX PWR_AP_xa" and "TX_PWR_AP_xb." Additionally, "Acceptable Receiver Interference Level_AP,x" can be set to twice the minimum of "Acceptable Receiver Interference Level_AP,xa" and "Acceptable Receiver Interference Level_AP,xb." The definition of each variable in Equation 4 is as described in Equation 3.

[0145] According to yet another embodiment of the present invention, the SR field x of the x-th 40 MHz frequency band may be determined as shown in Equation 5.

[0146] [Equation 5]

[0147] SRP_x=min(SRP_xa, SRP_xb)

[0148] in

[0149] SRP_xa=TX PWR_AP,xa+Acceptable Receiver Interference Level_AP,xa

[0150] SRP_xb=TX PWR_AP,xb+Acceptable Receiver Interference Level_AP,xb

[0151] Referring to Equation 5, "SRP_x" can be set to the minimum value of "SRP_xa" and "SRP_xb." The calculation method of "SRP_xa" and "SRP_xb" and the definition of each variable are as described in Equation 3. According to the embodiment of Equation 5, the operation of multiplying the SRP of the 20 MHz band by 2 is not performed, and the terminal can recognize in advance that "SRP_x" corresponds to the 20 MHz band.

[0152] According to yet another embodiment of the present invention, the SR field x of the x-th 40 MHz frequency band may be determined as shown in Equation 6.

[0153] [Equation 6]

[0154] SRP_x = TX PWR_AP,x + Acceptable Receiver Interference Level_AP,x

[0155] in

[0156] TX PWR_AP, x=min (TX PWR_AP, xa, TX PWR_AP, xb)

[0157] Acceptable Receiver Interference Level_AP,x=min(Acceptable Receiver Interference Level_AP,xa,Acceptable Receiver Interference Level_AP,xb)

[0158] Referring to Equation 6, "SRP_x" may be set to the sum of "TX PWR_AP,x" and "Acceptable Receiver Interference Level_AP,x". In this case, "TX PWR_AP,x" may be set to the minimum value between "TX PWR_AP_xa" and "TX_PWR_AP_xb". In addition, "Acceptable Receiver Interference Level_AP,x" may be set to the minimum value between "Acceptable Receiver Interference Level_AP,xa" and "Acceptable Receiver Interference Level_AP,xb". The definition of each variable in Equation 6 is as described in Equation 3. According to the embodiment of Equation 6, the terminal can pre-identify that "SRP_x" corresponds to the 20 MHz frequency band.

[0159] Figures 15 to 19 The method of configuring the HE-SIG-A and spatial reuse fields according to an embodiment of the present invention is illustrated. Figures 15 to 19 In each embodiment shown in FIG, repeated description of the same or corresponding parts as those of the embodiment of the previous figure will be omitted.

[0160] As described above, the HE-SIG-A of a triggered PPDU may include four SR fields. When the total bandwidth for transmitting the triggered PPDU is 160 MHz (or 80+80 MHz), each individual SR field may indicate the SRP of a single subband in units of 40 MHz. In this case, the triggered PPDU may be transmitted on at least one of the primary 80 MHz channel (hereinafter referred to as the P80 channel) and the secondary 80 MHz channel (hereinafter referred to as the S80 channel). However, an OBSS terminal receiving the triggered PPDU is unable to learn the frequency band configuration of the BSS in which the corresponding PPDU is transmitted. More specifically, when the total bandwidth for transmitting the triggered PPDU is 80+80 MHz, the OBSS terminal may not be able to identify the physical frequency bands of the P80 channel and the S80 channel that constitute the total bandwidth. Therefore, the OBSS terminal receiving the PPDU cannot identify which frequency band the SR field of the corresponding PPDU is used for. Furthermore, the OBSS terminal cannot identify which SR field among the SR fields is used to receive the subband of the corresponding PPDU. Therefore, a method is needed to resolve the ambiguity of the SR field identification of an OBSS terminal receiving a trigger-based PPDU.

[0161] Figure 15 The method for configuring the HE-SIG-A and spatial reuse fields of the trigger-based PPDU according to an embodiment of the present invention is illustrated. Figure 15 In an embodiment of the present invention, the HE-SIG-A of the HE-formatted PPDU may include a location field. The location field may indicate the first frequency band or the second frequency band that constitutes the total bandwidth. For example, when the total bandwidth for transmitting the trigger-based PPDUs 410 and 420 is 80+80 MHz, the location field of the HE-SIG-A may indicate the first 80 MHz frequency band or the second 80 MHz frequency band. According to an embodiment of the present invention, the first SR field and the second SR field of the HE-SIG-A may indicate the SRP of the first frequency band, and the third SR field and the fourth SR field of the HE-SIG-A may indicate the SRP of the second frequency band.

[0162] The first frequency band and the second frequency band can be classified by various methods. According to an embodiment, the first frequency band may be a low frequency band, and the second frequency band may be a high frequency band. According to another embodiment, the first frequency band may be a high frequency band, and the second frequency band may be a low frequency band. According to yet another embodiment, the first frequency band may be a frequency band of a P80 channel, and the second frequency band may be a frequency band of an S80 channel. Figure 15 In an embodiment of the present invention, the trigger-based PPDU 410 transmitted on the first frequency band may set the location field to 1 (or 0), and the trigger-based PPDU 420 transmitted on the second frequency band may set the location field to 0 (or 1). In an embodiment of the present invention, the first frequency band and the second frequency band indicate different 80 MHz frequency bands, but the present invention is not limited thereto.

[0163] An OBSS terminal receiving the trigger-based PPDUs 410 and 420 can identify the SRP of the subband in which the corresponding PPDUs 410 and 420 are received based on the location field information of the received PPDUs 410 and 420. If the location field information indicates the first frequency band, the OBSS terminal can obtain the SRP of the corresponding subband from at least one of the first SR field and the second SR field. However, if the location field information indicates the second frequency band, the OBSS terminal can obtain the SRP of the corresponding subband from at least one of the third SR field and the fourth SR field.

[0164] Figure 16 The diagram illustrates a method for configuring the HE-SIG-A and spatial reuse fields of a triggered PPDU according to another embodiment of the present invention. Figure 16 In an embodiment, when the total bandwidth for transmitting the trigger-based PPDUs 510 and 520 is 80+80 MHz, the SR field of the first frequency band may be set to the same value as the SR field of the second frequency band.

[0165] As described above, a STA transmitting a triggered PPDU 510 or 520 can carry the SRP information obtained from the trigger frame via the SR field of the triggered PPDU 510 or 520. In this case, the STA can repeatedly insert two pieces of SRP information into the SR field. For example, the SRP information for each subband obtained from the trigger frame may be a, b, c, and d. a and b may be the SRP information for the first frequency band, and c and d may be the SRP information for the second frequency band. In this case, a, b, a, and b may be included in the first through fourth SR fields of the triggered PPDU 510 transmitted on the first frequency band, respectively. Furthermore, c, d, c, and d may be included in the first through fourth SR fields of the triggered PPDU 520 transmitted on the second frequency band, respectively. That is, the first and second SR fields of the first frequency band are set to the same values ​​as the third and fourth SR fields of the second frequency band, respectively. As described above, the first and second frequency bands may indicate a high (or low) physical frequency band and a low (or high) physical frequency band, respectively. Alternatively, the first frequency band and the second frequency band may indicate a frequency band of a P80 channel and a frequency band of an S80 channel, respectively.

[0166] The OBSS terminal receiving the trigger-based PPDU 510, 520 obtains the first SRP from at least one of the first SR field and the third SR field of the received PPDU 510, 520. That is, because the information indicated by the first and second SR fields is the same as the information indicated by the third and fourth SR fields, the ambiguity of the SR field identification of the OBSS terminal can be resolved. According to an embodiment, the SRP information a, b, c, and d sent by the trigger frame can be set according to various rules. According to an embodiment, a and b can represent the SRP for the low frequency band, and c and d can represent the SRP for the high frequency band. According to another embodiment, a and b can represent the SRP for the high frequency band, and c and d can represent the SRP for the low frequency band. According to yet another embodiment, a and b can be set to the same values ​​as c and d, respectively.

[0167] Figure 17 FIG2 illustrates a method for configuring the HE-SIG-A and spatial reuse fields of a triggered PPDU according to another embodiment of the present invention. Figure 17 In an embodiment, the SR field of the first frequency band and the SR field of the second frequency band may be identified through a physical signaling method.

[0168] More specifically, the cyclic shift value of the triggered-based PPDU 610 transmitted on the first frequency band may be set differently from the cyclic shift value of the triggered-based PPDU 620 transmitted on the second frequency band. In this case, a first cyclic shift value applied to the first frequency band and a second cyclic shift value applied to the second frequency band may be pre-specified. Therefore, an OBSS terminal receiving a triggered-based PPDU 610 to which the first cyclic shift value is applied obtains the SRP information for the corresponding subband from at least one of the first and second SR fields of the corresponding PPDU 610. Furthermore, an OBSS terminal receiving a triggered-based PPDU 620 to which the second cyclic shift value is applied obtains the SRP information for the corresponding subband from at least one of the third and fourth SR fields of the corresponding PPDU 620.

[0169] Figure 18 FIG2 illustrates a method for configuring the HE-SIG-A and spatial reuse fields of a triggered PPDU according to another embodiment of the present invention. Figure 18 In an embodiment, the SR field of the first frequency band and the SR field of the second frequency band may be identified through a physical signaling method.

[0170] More specifically, the modulation scheme applied to the specific field of the trigger-based PPDU 720 transmitted on the second frequency band may be set differently from the modulation scheme applied to the specific field of the trigger-based PPDU 710 transmitted on the first frequency band. In this case, a first modulation scheme applied to the specific field transmitted on the first frequency band and a second modulation scheme applied to the specific field transmitted on the second frequency band may be pre-specified. According to an embodiment of the present invention, the specific field to which different modulation schemes are applied depending on the frequency band may be a repeated L-SIG (RL-SIG).

[0171] Therefore, the OBSS terminal receiving the trigger-based PPDU 710 including the RL-SIG to which the first modulation scheme is applied obtains the SRP information of the corresponding subband from at least one of the first SR field and the second SR field. In addition, the OBSS terminal receiving the trigger-based PPDU 720 including the RL-SIG to which the second modulation scheme is applied obtains the SRP information of the corresponding subband from at least one of the third SR field and the fourth SR field of the PPDU 720.

[0172] Figure 19 FIG2 illustrates a method for configuring the HE-SIG-A and spatial reuse fields of a triggered PPDU according to another embodiment of the present invention. Figure 19In an embodiment, the HE-SIG-A of an HE-formatted PPDU may include a non-contiguous frequency band indicator, which indicates whether the total bandwidth of the transmitted PPDU is non-contiguous. Therefore, the non-contiguous frequency band indicator can be used to identify whether the total bandwidth of the triggered PPDU is a continuous 160 MHz or a non-contiguous 80+80 MHz.

[0173] The OBSS terminal receiving the triggered PPDU 810, 820 can determine the SR operation based on the non-contiguous band indicator of the received PPDU 810, 820. If the non-contiguous band indicator is set to 0 (i.e., if the total bandwidth of the transmitted PPDU is continuous), the OBSS terminal can identify each subband constituting the total bandwidth of the transmitted PPDU and the SR field corresponding thereto. Therefore, the OBSS terminal can perform the SR operation based on the obtained SR field. However, if Figure 19 As shown in , if the non-contiguous band indicator is set to 1 (i.e., if the total bandwidth of the transmitted PPDU is non-contiguous), the OBSS terminal cannot identify each subband constituting the total bandwidth of the transmitted PPDU and the SR field corresponding thereto. Therefore, the OBSS terminal may not be able to perform the above-mentioned SR operation.

[0174] Meanwhile, as described above, in the above embodiment, the first frequency band and the second frequency band may indicate a high (or low) physical frequency band and a low (or high) physical frequency band, respectively. However, according to another embodiment of the present invention, the first frequency band and the second frequency band may indicate a frequency band of a P80 channel and a frequency band of an S80 channel, respectively.

[0175] Figure 20 and 21 Another embodiment of a method for setting the spatial reuse field of a triggered PPDU is shown. As described above, when the total bandwidth for transmitting the triggered PPDU is 160 MHz (or 80+80 MHz), each SR field of the triggered PPDU can indicate the SRP for each subband in units of 40 MHz.

[0176] According to an embodiment of the present invention, when the total bandwidth for transmitting a triggered PPDU is a contiguous frequency band (e.g., 80 MHz, 160 MHz, etc.), the physical frequency bands comprising the total bandwidth are determined by a predetermined rule. Therefore, an OBSS terminal receiving a triggered PPDU transmitted over a contiguous frequency band can identify the physical frequency band over which the triggered PPDU is transmitted. However, when the total bandwidth for transmitting a triggered PPDU is composed of non-contiguous frequency bands (e.g., 80+80 MHz), the physical frequency bands comprising the total bandwidth may not be predetermined. Therefore, an OBSS terminal receiving a triggered PPDU transmitted over a non-contiguous frequency band cannot identify the frequency band for which the SR field of the corresponding PPDU is used. More specifically, when the total bandwidth for transmitting a triggered PPDU is 80+80 MHz, the OBSS terminal cannot identify a set of SR fields (i.e., at least one of the first and second SR fields) and a set of SR fields (i.e., at least one of the third and fourth SR fields) that can be used to obtain the SRP for the subband of the received PPDU. Therefore, when a trigger-based PPDU is transmitted on a non-contiguous frequency band, a method is needed to resolve the ambiguity of the SR field identification of the OBSS terminal receiving it.

[0177] Figure 20 Another embodiment of the method of setting the spatial reuse field of the trigger-based PPDU to solve this problem is shown in FIG. Figure 20 In this embodiment, when the total bandwidth for transmitting a triggered PPDU is 80+80 MHz, the representative value among the SRPs for the two corresponding 40 MHz bands can be set as the SRP of the corresponding band. More specifically, the representative value among the SRPs of the first and third 40 MHz bands can be used as the first SRPs for the first and third 40 MHz bands. Therefore, the first and third SR fields of the triggered PPDU represent the same representative value. Similarly, the representative value among the SRPs of the second and fourth 40 MHz bands can be used as the second SRPs for the second and fourth 40 MHz bands. Therefore, the second and fourth SR fields of the triggered PPDU represent the same representative value. In this case, the first and second 40 MHz bands constitute the first frequency band over which the triggered PPDU is transmitted, and the third and fourth 40 MHz bands constitute the second frequency band over which the triggered PPDU is transmitted. According to an embodiment of the present invention, a smaller value among a plurality of SRPs may be set as a representative value of the corresponding SRP.

[0178] An OBSS terminal receiving a triggered PPDU with a total bandwidth of 80+80 MHz can obtain a first SRP from at least one of the first and third SR fields of the received PPDU, and can obtain a second SRP from at least one of the second and fourth SR fields of the received PPDU. That is, because the information indicated by the first and second SR fields is the same as the information indicated by the third and fourth SR fields, the ambiguity in the SR field identification of the OBSS terminal can be resolved.

[0179] On the other hand, when the total bandwidth for transmitting triggered PPDUs is 160 MHz, each SR field can indicate the SRP of a different subband in units of 40 MHz. That is, the first SR field indicates the SRP of the first 40 MHz band, the second SR field indicates the SRP of the second 40 MHz band, the third SR field indicates the SRP of the third 40 MHz band, and the fourth SR field indicates the SRP of the fourth 40 MHz band. In this case, the first 40 MHz band to the fourth 40 MHz band constitute the total bandwidth of 160 MHz for transmitting triggered PPDUs. In this way, by allowing the SR field of a triggered PPDU transmitted on a continuous frequency band to indicate the SRP of each subband, it is possible to perform SR operations more suitable for each subband.

[0180] Figure 21 FIGURE 1 illustrates another embodiment of a method for setting and using the spatial reuse field of a triggered PPDU. Figure 21 In an embodiment, each SR field of a triggered PPDU may indicate SRPs for different subbands, and an OBSS terminal receiving the PPDU may select an SRP for SR operation of a corresponding subband from among the SRPs indicated by the multiple SR fields.

[0181] More specifically, even if the total bandwidth for transmitting a trigger-based PPDU is 80+80 MHz, each SR field can indicate the SRP of a different subband in units of 40 MHz. That is, the first SR field indicates the SRP of the first 40 MHz band, the second SR field indicates the SRP of the second 40 MHz band, the third SR field indicates the SRP of the third 40 MHz band, and the fourth SR field indicates the SRP of the fourth 40 MHz band. In this case, the first 40 MHz band and the second 40 MHz band constitute the first frequency band for transmitting the trigger-based PPDU, and the third 40 MHz band and the fourth 40 MHz band constitute the second frequency band for transmitting the trigger-based PPDU.

[0182] An OBSS terminal receiving a triggered PPDU with a total bandwidth of 80+80 MHz uses the smaller value between the two corresponding SR fields as the SRP for the corresponding subband. That is, the smaller value between the first and third SR field values ​​is used for the SRP for the first and / or third 40 MHz bands. Additionally, the smaller value between the second and fourth SR field values ​​is used for the SRP for the second and / or fourth 40 MHz bands.

[0183] Figure 22 FIG2 illustrates a method for configuring the HE-SIG-A and spatial reuse fields of a triggered PPDU according to another embodiment of the present invention. Figure 22 In this embodiment, to resolve the ambiguity of the SR field identification for OBSS terminals, SR operations can be restricted in trigger-based PPDUs sent over non-contiguous frequency bands. More specifically, the SR field in trigger-based PPDUs 910 and 920 sent over the 80+80 MHz frequency band can indicate a predetermined value that disallows SR operations. To this end, the AP can carry an SRP in the trigger frame that indicates the predetermined value that disallows SR operations.

[0184] Figure 23 FIG2 illustrates a method for signaling a spatial reuse field of a triggered PPDU according to another embodiment of the present invention. Figure 23 In an embodiment, when the total bandwidth indicated by the bandwidth field of the triggered PPDU is 80+80 MHz or 160 MHz, the SR field may indicate the SRP for the sub-band of the 20 MHz bandwidth. Figure 23 In the embodiment of the present invention, when the total bandwidth of the trigger-based PPDU is 20 MHz, 40 MHz or 80 MHz, the value indicated by each SR field is the same as Figure 13 Same as shown in the figure.

[0185] according to Figure 23 In an embodiment, when the total bandwidth for transmitting a triggered PPDU is 160 MHz (or 80+80 MHz), the value of the SR field for the first 80 MHz band can be set to a different value from the value of the SR field for the second 80 MHz band. That is, the first to fourth SR fields of the triggered PPDU transmitted on the first frequency band respectively indicate the SRP of the first 20 MHz band to the fourth 20 MHz band of the first frequency band. In addition, the first to fourth SR fields of the triggered PPDU transmitted on the second frequency band respectively indicate the SRP of the first 20 MHz band to the fourth 20 MHz band of the second frequency band. In this case, the first to fourth SR fields of the first frequency band and the first to fourth SR fields of the second band can be determined independently of each other.

[0186] Therefore, in order to indicate the SRP in units of 20 MHz in a total bandwidth of 160 MHz (or 80 + 80 MHz), a maximum of eight SRP bits should be carried in the trigger frame. Therefore, the length of the trigger frame can be determined to be variable based on the total bandwidth information. That is, if the total bandwidth is 20 MHz, 40 MHz, or 80 MHz, the trigger frame carries a total of 16 bits of SRP, and if the total bandwidth is 160 MHz (or 80 + 80 MHz), the trigger frame carries a total of 32 bits of SRP.

[0187] Figure 24 The figure illustrates a method for signaling the bandwidth field according to an embodiment of the present invention. In the above embodiment, it is necessary to identify whether the total bandwidth of the trigger-based PPDU is continuous 160 MHz or non-contiguous 80+80 MHz. According to an embodiment of the present invention, whether the total bandwidth of the PPDU is continuous can be signaled via HE-SIG-A.

[0188] According to an embodiment of the present invention, as mentioned above Figure 19 As described above, the HE-SIG-A of the HE format PPDU may include a non-contiguous frequency band indicator. Therefore, the non-contiguous frequency band indicator can be used to identify whether the total bandwidth of the trigger-based PPDU is a contiguous 160 MHz or a non-contiguous 80+80 MHz.

[0189] According to another embodiment of the present invention, Figure 24 As shown in , whether the total bandwidth of the PPDU is continuous can be signaled via the bandwidth field of the HE-SIG-A. More specifically, non-contiguous bandwidth can be indicated via a predetermined index of the bandwidth field of the HE-SIG-A. For example, indexes 0, 1, 2, and 3 of the bandwidth field can represent 20 MHz, 40 MHz, 80 MHz, and 160 MHz, respectively. In addition, index 4 of the bandwidth field can represent non-contiguous 80+80 MHz. When the bandwidth field of the triggered PPDU indicates continuous 160 MHz, the OBSS terminal receiving the PPDU can perform SR operation at 160 MHz. However, when the bandwidth field of the triggered PPDU indicates non-contiguous 80+80 MHz, the OBSS terminal can perform SR operation at 80 MHz, which includes the subband in which the corresponding PPDU is received.

[0190] According to another embodiment of the present invention, whether the total bandwidth of the transmitted PPDU is continuous can be identified based on whether the corresponding SR fields are set to the same value. For example, when the bandwidth field of the trigger-based PPDU indicates 160 MHz, and the first SR field and the second SR field are set to the same value as the third SR field and the fourth SR field, respectively, the total bandwidth over which the trigger-based PPDU is transmitted can be identified as 80+80 MHz.

[0191] Although the present invention is described by using wireless LAN communication as an example, the present invention is not limited thereto and can be similarly applied to other communication systems, such as cellular communication, etc. In addition, although the method, apparatus, and system of the present invention are described in conjunction with specific embodiments, some or all of the components and operations of the present invention can be implemented by using a computer system having a general hardware structure.

[0192] The embodiments described in detail of the present invention may be implemented by various means. For example, the embodiments of the present invention may be implemented by hardware, firmware, software and / or a combination thereof.

[0193] In the case of hardware implementation, the method according to the embodiment of the present invention can be implemented by one or more of an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microcontroller, a microprocessor, etc.

[0194] In the case of firmware implementation or software implementation, the method according to the embodiment of the present invention can be implemented by modules, processes, functions, etc. that perform the operations described above. The software code can be stored in a memory and operated by a processor. The processor can be equipped with a memory internally or externally, and the memory can exchange data with the processor through various publicly known means.

[0195] The description of the present invention is for illustration, and those skilled in the art will be able to understand that, without changing the technical ideas or its essential features, the present invention can be easily modified into other detailed forms. Therefore, it should be understood that the above embodiments are intended to be illustrative in various senses, rather than restrictive. For example, each component described as a single type can be implemented as distributed, and similarly, the components described as distributed can also be implemented in an associated form.

[0196] The scope of the present invention is indicated by the claims to be described below, rather than the detailed description, and it is to be interpreted that the meaning and scope of the claims and all changes or modifications derived from equivalents thereof fall within the scope of the present invention.

[0197] Industrial Applicability

[0198] Various exemplary embodiments of the present invention have been described with reference to the IEEE 802.11 system, however, the present invention is not limited thereto and the present invention can be applied to various types of mobile communication devices, mobile communication systems, and the like.

Claims

1. A wireless communication terminal, comprising: processor; and Communication unit, Wherein, the processor is configured to: receiving a trigger frame indicating an uplink multi-user transmission, and sending a trigger-based PHY protocol data unit PPDU in response to the trigger frame, The trigger-based PPDU includes spatial reuse parameters for spatial reuse operations of overlapping basic service sets (OBSS) terminals, and When the total bandwidth for performing the uplink multi-user transmission in response to the trigger frame is 80+80 MHz, the spatial reuse parameter of the first 80 MHz frequency band of the total bandwidth is set to the same value as the spatial reuse parameter of the second 80 MHz frequency band of the total bandwidth.

2. The wireless communication terminal according to claim 1, in, The trigger-based PPDU's high-efficiency signaling field A HE-SIG-A includes multiple spatial reuse fields, and Each of the plurality of spatial reuse fields includes a spatial reuse parameter of a corresponding subband constituting the total bandwidth.

3. The wireless communication terminal according to claim 2, in, The plurality of spatial reuse fields include a first spatial reuse field, a second spatial reuse field, a third spatial reuse field, and a fourth spatial reuse field, The first spatial reuse field indicates a first spatial reuse parameter of the first 80 MHz frequency band. The second spatial reuse field indicates a second spatial reuse parameter of the first 80 MHz frequency band. The third spatial reuse field indicates a third spatial reuse parameter of the second 80 MHz frequency band. The fourth spatial reuse field indicates a fourth spatial reuse parameter of the second 80 MHz frequency band, and The first spatial reuse parameter and the third spatial reuse parameter are set to the same value as each other, and the second spatial reuse parameter and the fourth spatial reuse parameter are set to the same value as each other.

4. The wireless communication terminal according to claim 2, in, The plurality of spatial reuse fields carry the spatial reuse parameters obtained from the trigger frame.

5. The wireless communication terminal according to claim 1, in, The total bandwidth is indicated by the bandwidth field of the HE-SIG-A of the triggered PPDU. The wireless communication terminal according to claim 1 , in, The spatial reuse parameter is set based on a transmission power of the PPDU containing the trigger frame and an acceptable interference level of an access point AP that transmits the PPDU containing the trigger frame.

7. The wireless communication terminal according to claim 1, in, The spatial reuse operation is performed based on a received signal strength of the PPDU including the trigger frame measured by the OBSS terminal and the spatial reuse parameter obtained by the OBSS terminal.

8. The wireless communication terminal according to claim 7, in, The spatial reuse operation includes adjusting the transmission power of the OBSS terminal based on the spatial reuse parameter, and The transmission power of the OBSS terminal is set to be lower than a value obtained by subtracting the received signal strength from a value of the spatial reuse parameter.

9. The wireless communication terminal according to claim 7, wherein: The spatial reuse operation includes allowing transmission of the OBSS terminal only when the expected transmission power of the OBSS terminal is lower than a value obtained by subtracting the received signal strength from a value of the spatial reuse parameter.

10. The wireless communication terminal according to claim 1, wherein The OBSS terminal obtains the spatial reuse parameter from at least one of the trigger frame and the trigger-based PPDU.

11. A wireless communication method for a wireless communication terminal, the method comprising: receiving a trigger frame indicating an uplink multi-user transmission; sending a trigger-based PHY protocol data unit PPDU in response to the trigger frame, The trigger-based PPDU includes spatial reuse parameters for spatial reuse operations of overlapping basic service sets (OBSS) terminals, and When the total bandwidth for performing the uplink multi-user transmission in response to the trigger frame is 80+80 MHz, the spatial reuse parameter of the first 80 MHz frequency band of the total bandwidth is set to the same value as the spatial reuse parameter of the second 80 MHz frequency band of the total bandwidth.

12. The wireless communication method according to claim 11, in, The trigger-based PPDU's high-efficiency signaling field A HE-SIG-A includes multiple spatial reuse fields, and Each of the plurality of spatial reuse fields includes a spatial reuse parameter of a corresponding subband constituting the total bandwidth.

13. The wireless communication method according to claim 12, in, The plurality of spatial reuse fields include a first spatial reuse field, a second spatial reuse field, a third spatial reuse field, and a fourth spatial reuse field, The first spatial reuse field indicates a first spatial reuse parameter of the first 80 MHz frequency band. The second spatial reuse field indicates a second spatial reuse parameter of the first 80 MHz frequency band. The third spatial reuse field indicates a third spatial reuse parameter of the second 80 MHz frequency band. The fourth spatial reuse field indicates a fourth spatial reuse parameter of the second 80 MHz frequency band, and The first spatial reuse parameter and the third spatial reuse parameter are set to the same value as each other, and the second spatial reuse parameter and the fourth spatial reuse parameter are set to the same value as each other.

14. The wireless communication method according to claim 12, in, The plurality of spatial reuse fields carry the spatial reuse parameters obtained from the trigger frame.

15. The wireless communication method according to claim 11, in, The total bandwidth is indicated by the bandwidth field of the HE-SIG-A of the triggered PPDU.

16. The wireless communication method according to claim 11, in, The spatial reuse parameter is set based on a transmission power of the PPDU containing the trigger frame and an acceptable interference level of an access point AP that transmits the PPDU containing the trigger frame.

17. The wireless communication method according to claim 11, wherein: The spatial reuse operation is performed based on a received signal strength of the PPDU including the trigger frame measured by the OBSS terminal and the spatial reuse parameter obtained by the OBSS terminal.

18. The wireless communication method according to claim 17, in, The spatial reuse operation includes adjusting the transmission power of the OBSS terminal based on the spatial reuse parameter, and The transmission power of the OBSS terminal is set to be lower than a value obtained by subtracting the received signal strength from a value of the spatial reuse parameter.

19. The wireless communication method according to claim 17, wherein: The spatial reuse operation includes allowing transmission of the OBSS terminal only when the expected transmission power of the OBSS terminal is lower than a value obtained by subtracting the received signal strength from a value of the spatial reuse parameter.

20. The wireless communication method according to claim 11, wherein: The OBSS terminal obtains the spatial reuse parameter from at least one of the trigger frame and the trigger-based PPDU.

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