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 patent application No. 201780022351.4 (PCT / KR2017 / 003662), filed on October 8, 2018, with an international filing date of April 3, 2017, entitled "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 operations of overlapping basic service sets, and more particularly, to a wireless communication method and a wireless communication terminal for supporting spatial reuse operations of overlapping basic service sets to efficiently utilize wireless resources. Background Technology

[0003] In recent years, with the expansion of mobile device supply, wireless LAN technology, which can provide fast wireless internet services to mobile devices, has gained attention. Wireless LAN technology allows mobile devices, including smartphones, tablets, laptops, portable multimedia players, embedded devices, and more, to wirelessly access the internet in their homes, offices, or specific service areas based on short-range wireless communication technology.

[0004] Since using the 2.4 GHz frequency to support initial wireless LAN technology, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 has commercialized or developed various technical standards. First, IEEE 802.11b, using the 2.4 GHz band, supported a maximum communication speed of 11 Mbps. Compared to the significantly congested 2.4 GHz band, IEEE 802.11a, commercialized after IEEE 802.11b, used the 5 GHz band instead of 2.4 GHz to reduce interference and increased the communication speed to a maximum of 54 Mbps through OFDM technology. However, a drawback of IEEE 802.11a is its shorter communication range compared to IEEE 802.11b. Furthermore, similar to IEEE 802.11b, IEEE 802.11g, using the 2.4 GHz band to achieve a maximum communication speed of 54 Mbps and satisfying backward compatibility, has attracted significant attention and, in terms of communication range, is superior to IEEE 802.11a.

[0005] Furthermore, IEEE 802.11n has been developed as a technical standard to overcome the communication speed limitations identified as a weakness in wireless LANs. IEEE 802.11n aims to improve network speed and reliability and extend the operating range of wireless networks. More specifically, IEEE 802.11n supports high throughput (HT), with data processing speeds of up to 540 Mbps or higher, and further, it is based on multiple-input multiple-output (MIMO) technology, where multiple antennas are used on both sides of the transmitting and receiving units to minimize transmission errors and optimize data speed. Additionally, the standard can use a coding scheme that transmits multiple superimposed copies to increase data reliability.

[0006] With the active provision of wireless LANs and the further diversification of applications using wireless LANs, there has been a growing demand for new wireless LAN systems that support higher throughput (Very High Throughput (VHT)) than those supported by IEEE 802.11n. Among these, IEEE 802.11ac supports wide bandwidth (80 to 160 MHz) in the 5 GHz frequency band. The IEEE 802.11ac standard is defined only in the 5 GHz band, but initial 11ac chipsets even support operation in the 2.4 GHz band for backward compatibility with existing 2.4 GHz band products. Theoretically, according to this standard, wireless LAN speeds of at least 1 Gbps can be enabled across multiple stations, and maximum single-link speeds can reach at least 500 Mbps. This is achieved by extending the concepts of the wireless interface accepted by 802.11n, such as wider wireless bandwidth (maximum 160 MHz), more MIMO spatial streams (maximum 8), multi-user MIMO, and high-density modulation (maximum 256 QAM). Furthermore, IEEE 802.11ad has been offered as a solution for transmitting data using the 60GHz band instead of the existing 2.4GHz / 5GHz band. IEEE 802.11ad is a transmission standard that provides speeds up to 7Gbps using beamforming technology and is suitable for high bit-rate motion streaming, such as massive amounts of data or uncompressed HD video. However, its drawback is that the 60GHz band is difficult to penetrate obstacles, limiting its use to devices operating in close proximity.

[0007] Meanwhile, in recent years, as the next-generation wireless LAN standard following 802.11ac and 802.11ad, discussions have continued regarding technologies for providing efficient and high-performance wireless LAN communication in high-density environments. Specifically, in next-generation wireless LAN environments, with the presence of high-density stations and access points (APs), there is a need to provide communication with high spectral efficiency indoors / outdoors, and various technologies are required to achieve this communication. Summary of the Invention

[0008] Technical issues

[0009] The present invention aims to provide high-efficiency / high-performance wireless LAN communication in high-density environments as described above.

[0010] The present invention aims to resolve the ambiguity of the spatial reuse field identifier of BSS (or overlapping BSS) terminals receiving triggered PPDUs.

[0011] The present invention aims to provide a wireless communication method and a wireless communication terminal in a high-density environment including an overlapping set of basic services.

[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, the terminal including: a processor; and a communication unit, wherein the processor receives a trigger frame indicating uplink multi-user transmission, and in response to the received trigger frame sends a trigger-based PHY protocol data unit (PPDU), wherein the trigger-based PPDU includes spatial reuse parameters for spatial reuse operations of Overlapping Basic Service Set (OBSS) terminals.

[0015] Furthermore, 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; and in response to the received trigger frame, transmitting a trigger-based PHY protocol data unit (PPDU); wherein the trigger-based PPDU includes spatial reuse parameters for spatial reuse operations of an Overlapping Basic Service Set (OBSS) terminal.

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

[0017] The high-efficiency signal field A (HE-SIG-A) of the trigger-based PPDU can contain multiple spatial reuse fields, and these multiple spatial reuse fields can carry spatial reuse parameters obtained from the trigger frame. Each of the multiple spatial reuse fields can indicate the spatial reuse parameters of a single subband used to compose the total bandwidth of the transmission on which the trigger-based PPDU is performed.

[0018] Multiple 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 of the transmission of the trigger-based PPDU performed thereon 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 used for the second frequency band, respectively.

[0019] When the total bandwidth of a trigger-based PPDU transmission performed on it is less than or equal to a predetermined bandwidth, the spatial reuse field can indicate the spatial reuse parameters for a subband of the first frequency bandwidth, and when the total bandwidth of a trigger-based PPDU transmission performed on it exceeds the predetermined bandwidth, the spatial reuse field can indicate the spatial reuse parameters for a subband of the second frequency bandwidth, which is wider than the first frequency bandwidth.

[0020] Spatial reuse parameters can be set based on the transmission power of the PPDU containing the trigger frame and the acceptable interference level of the basic wireless communication terminal that transmits the PPDU containing the trigger frame.

[0021] The space reuse operation of the OBSS terminal may include adjusting the transmission power of the OBSS terminal based on space reuse parameters.

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

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

[0024] The OBSS terminal can obtain space reuse parameters from at least one of the trigger frame and the trigger-based PPDU.

[0025] Beneficial effects

[0026] According to embodiments of the present invention, the ambiguity of the spatial reuse field identifier of BSS (or overlapping BSS) terminals receiving triggered PPDUs can be resolved.

[0027] Furthermore, according to embodiments of the present invention, if the received frame is determined to be an inter-BSS frame, spatial reuse operations can be performed, thereby effectively utilizing radio resources.

[0028] According to embodiments of the present invention, it is possible to increase the overall resource utilization in a contention-based channel access system and improve the performance of a wireless LAN system. Attached Figure Description

[0029] Figure 1 The illustration shows a wireless LAN system according to an embodiment of the present invention.

[0030] Figure 2 The illustration shows a wireless LAN system according to another embodiment of the present invention.

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

[0032] Figure 4 The diagram illustrates the configuration of an access point according to an embodiment of the present invention.

[0033] Figure 5 This diagram illustrates the process of setting up a link between a STA and an AP.

[0034] Figure 6 The diagram illustrates the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0035] Figure 7 The illustration shows a channel access method using spatial reuse operation according to an embodiment of the present invention.

[0036] Figure 8 The illustration shows the SR operation of a terminal according to an embodiment of the present invention when a PPDU containing a trigger frame is sent in the OBSS.

[0037] Figure 9 A more detailed illustration shows the SR operation of a terminal according to an embodiment of the present invention when a PPDU containing a trigger frame is sent in the OBSS.

[0038] Figure 10 The illustration shows an example of a terminal performing SR operation based on a contention process when a PPDU containing a trigger frame is sent in the OBSS.

[0039] Figure 11 The illustration shows an example of how a terminal sets up a NAV when a PPDU containing a trigger frame is sent in the OBSS.

[0040] Figure 12 The illustration shows an embodiment of transmitting space reuse parameters via a trigger frame and a corresponding trigger-based PPDU.

[0041] Figure 13 The illustration shows a method for transmitting a space reuse field of a trigger-based PPDU using signals according to an embodiment of the present invention.

[0042] Figure 14 The illustration shows an example of a method for setting up a space reuse field based on a triggered PPDU.

[0043] Figures 15 to 19The illustration shows a method for configuring HE-SIG-A and space reuse fields according to an embodiment of the present invention.

[0044] Figure 20 The illustration shows another embodiment of a method for setting up a space reuse field based on a triggered PPDU.

[0045] Figure 21 The illustration shows another embodiment of a method for setting up and using a space reuse field based on a trigger-based PPDU.

[0046] Figure 22 The illustration shows a method for configuring HE-SIG-A and space reuse fields based on a triggered PPDU according to another embodiment of the present invention.

[0047] Figure 23 The illustration shows a method for sending a space reuse field based on a trigger-based PPDU using a signal, according to another embodiment of the present invention.

[0048] Figure 24 The illustration shows a method for using a signal transmission bandwidth field according to an embodiment of the present invention. Detailed Implementation

[0049] In consideration of the functionality of this invention, the terminology used in this specification employs currently widely used and common terms; however, the terminology may change according to the intent, habits, and emergence of new technologies of those skilled in the art. Furthermore, in certain cases, there are terms arbitrarily chosen by the applicant, and in such cases, their meaning will be described in the corresponding descriptive section of the invention. Therefore, it should be understood that the terminology used in this specification should be analyzed not only based on the name of the term, but also on its substantive meaning and the content of the entire specification.

[0050] Throughout this specification and the following claims, when an element is described as being “coupled” to another element, that element may be “directly coupled” to the other element or “electrically coupled” to the other element via a third element. Furthermore, unless explicitly stated otherwise, the words “comprising” and variations such as “including” or “includes” will be understood to implicitly include the stated element but do not exclude any other element. Additionally, limitations based on specific thresholds such as “or more” or “or less” may be appropriately replaced by “greater than” or “less than”, respectively.

[0051] This application claims priority and benefits to Korean Patent Applications 10-2016-0040551, 10-2016-0074091, 10-2016-0086044 and 10-2016-0093813 filed with the Korean Intellectual Property Office, and the embodiments and matters mentioned that form the basis of the priority as described in the respective applications will be included in the specific embodiments of this application.

[0052] Figure 1 This diagram illustrates 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 have successfully synchronized with each other to communicate. Typically, a BSS can be divided into a Infrastructure BSS and Independent BSSs (IBSSs), and... Figure 1 The diagram shows the basic structure BSS between them.

[0053] As in Figure 1 As shown in the diagram, 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 that provide distributed services, and a distribution system (DS) that connects multiple access points PCP / AP-1 and PCP / AP-2.

[0054] A station (STA) is a predetermined device comprising a Media Access Control (MAC) conforming to the IEEE 802.11 standard and a physical layer interface for wireless media, and broadly includes both non-access point (non-AP) stations and access point (AP) stations. Furthermore, 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 can generate frames to be transmitted via a wireless network, or process frames received via a wireless network, and further performs various processes for controlling the station. Additionally, the communication unit is functionally connected to the processor and transmits and receives frames via the wireless network used for the station. According to the invention, "terminal" can be used as a term including user equipment (UE).

[0055] An access point (AP) is an entity that provides access to a distribution system (DS) via wireless media for its associated stations. In a BSS infrastructure, communication between non-AP stations is generally performed via the AP, but direct communication between non-AP stations is even permitted when a direct link is configured. In this invention, the AP is used as a concept encompassing a Personal BSS Coordination Point (PCP), and broadly can include concepts including a central controller, base station (BS), node B, base transceiver system (BTS), and site controller. In this invention, an AP can also be referred to as a base station wireless communication terminal. The term "base station wireless communication terminal" can be used broadly and includes APs, base stations, eNBs (i.e., e-node Bs), and transmission points (TPs). Furthermore, a base station wireless communication terminal can include various types of wireless communication terminals that allocate media resources and perform scheduling of communication with multiple wireless communication terminals.

[0056] Multiple infrastructure BSSs can be interconnected via a distributed system (DS). In this case, the multiple BSSs connected via the distributed system are called an extended service set (ESS).

[0057] Figure 2 The illustration shows a standalone BSS according to another embodiment of the present invention, which is a wireless LAN system. Figure 2 In the embodiments, the same as or corresponding to Figure 1 Repeated descriptions of certain embodiments will be omitted.

[0058] Because in Figure 2 The BSS3 shown in the diagram is an independent BSS and does not include an access point (AP). All stations STA6 and STA7 are not connected to the AP. Independent BSSs are not allowed to access the distributed system and form self-contained networks. Within an independent BSS, the corresponding stations STA6 and STA7 can be directly interconnected.

[0059] Figure 3 This is a block diagram illustrating the configuration of station 100 according to an embodiment of the present invention. (As shown in...) Figure 3 As shown in the figure, the 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. According to this embodiment, the communication unit 120 may include at least one communication module using different frequency bands. For example, the communication unit 120 may include communication modules with different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. According to one embodiment, the station 100 may include communication modules using a frequency band of 6 GHz or higher, and communication modules using a frequency band of 6 GHz or lower. The corresponding communication modules can perform wireless communication with the AP or external station according to the wireless LAN standard of the frequency band supported by the corresponding communication module. The communication unit 120 may operate only one communication module at a time, or operate multiple communication modules simultaneously, depending on the performance and requirements of the station 100. When the station 100 includes multiple communication modules, each communication module can be implemented by an independent component, or multiple modules can be integrated into a single chip. In embodiments of the invention, the communication unit 120 may represent a radio frequency (RF) communication module for processing RF signals.

[0061] Secondly, 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 using various input devices, and the processor 110 can control the station 100 based on the received user input. Furthermore, the user interface unit 140 can execute outputs based on commands from the processor 110 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 based on control commands from the processor 110, such as content executed by the processor 110 or a user interface. Furthermore, the memory 160 stores the control program and various result data used in the station 100. The control program may include the access program required for the station 100 to connect to the AP or an external station.

[0063] The processor 110 of the present invention can execute various commands or programs and process data in 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 communication configuration messages sent by the AP. Furthermore, the processor 110 can read information about the priority conditions of the station 100 included in the communication configuration messages and request access to the AP based on the information about the priority conditions of the station 100. The processor 110 of the present invention can represent the main control unit of the station 100, and according to this embodiment, the processor 110 can represent a control unit for individually controlling certain components of the station 100, such as the communication unit 120, etc. That is, 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. The processor 110 controls various operations of wireless signal transmission / reception of the station 100 according to an embodiment of the present invention. Detailed embodiments thereof will be described below.

[0064] exist Figure 3 The station 100 illustrated in the diagram is a block diagram according to an embodiment of the present invention, where individual blocks are illustrated as logically distinct device elements. Therefore, the elements of the device can be installed in a single chip or multiple chips depending on the device design. For example, the processor 110 and the communication unit 120 can be implemented as a 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, can be selectively disposed in the station 100.

[0065] Figure 4 This is a block diagram illustrating the configuration of an AP 200 according to an embodiment of the present invention. (As shown in...) Figure 4 As illustrated in the figure, 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 In the AP200 components, and... Figure 2 The components of station 100 are the same or correspond to Figure 2 Repeated descriptions of parts of station 100 will be omitted.

[0066] refer to Figure 4 The AP 200 according to the invention includes a communication unit 220 that operates a BSS in at least one frequency band. (As in...) Figure 3As described in the embodiments, the communication unit 220 of AP 200 may also include multiple communication modules using different frequency bands. That is, AP 200 according to embodiments 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, AP 200 may include communication modules using frequency bands of 6 GHz or higher, and communication modules using frequency bands of 6 GHz or lower. Each communication module may perform wireless communication with the station according to the wireless LAN standard of the frequency band supported by the respective communication module. 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 AP 200. In embodiments of the present invention, communication unit 220 may represent a radio frequency (RF) communication module for processing RF signals.

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

[0068] Figure 5 This is a schematic diagram illustrating the process of setting up the link between the STA and the AP.

[0069] refer to Figure 5 In a broad sense, the link between STA 100 and AP 200 is set up through three steps: scanning, authentication, and association. First, the scanning step is where STA 100 obtains access information from the BSS operated by AP 200. Methods for performing the scan include a passive scanning method, in which AP 200 obtains information by periodically sending beacon messages (S101), and an active scanning method, in which STA 100 sends a probe request to AP (S103) and obtains access information by receiving probe responses from AP (S105).

[0070] STA 100, having successfully received wireless access information during 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 from AP 200 (S109b). In this specification, association primarily refers to wireless association; however, the invention is not limited thereto, and association can broadly include both wireless and wired associations.

[0071] Meanwhile, the 802.1X-based authentication step (S111) and the IP address acquisition step via DHCP (S113) can be performed separately. Figure 5 In this context, authentication server 300 is the server that handles 802.1X-based authentication for STA 100, and can exist in a physical association with AP 200 or as a standalone server.

[0072] Figure 6 The diagram illustrates the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0073] Terminals performing wireless LAN communication check if the channel is busy by performing carrier sensing before transmitting data. When a wireless signal with a predetermined strength or higher is sensed, the corresponding channel is determined to be busy, and the terminal delays access to the corresponding channel. This process is called Clear Channel Assessment (CCA), and the level at which the corresponding signal is sensed is called the CCA threshold. When a wireless signal received by the terminal with a strength of CCA threshold or higher indicates that the terminal is a receiver, the terminal processes the received radio signal. Conversely, when no wireless signal is sensed in the corresponding channel, or a wireless signal with a strength less than the CCA threshold is sensed, the channel is determined to be idle.

[0074] When the channel is determined to be idle, each terminal with data to transmit performs a backoff procedure after the inter-frame space (IFS) time, such as the Arbitrated IFS (AIFS), PCF IFS (PIFS), etc., 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). Each terminal prepares as the time slot decreases, and terminals that have completely exhausted their time slots attempt to access the corresponding channel, provided that a random number is determined by the corresponding terminal during the idle period of the channel. Therefore, the interval at which each terminal performs the backoff procedure is called the contention window interval.

[0075] When a specific terminal successfully accesses the channel, it can transmit data via that channel. However, when a terminal attempting to access conflicts with another terminal, the conflicting terminals are assigned new random numbers to re-execute the backoff process. According to one embodiment, it can be determined that the random number reassigned to each terminal is within the range (2*CW), which is twice the range (contention window, CW) of the random numbers previously used by the corresponding terminal. Simultaneously, each terminal attempts to access the channel again in the next contention window interval by re-executing the backoff process, and in this case, each terminal begins the backoff process from the time slot period maintained within the previous contention window interval. In this way, terminals performing wireless LAN communication can avoid conflicts with each other on a specific channel.

[0076] Multi-user transmission

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

[0078] 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 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 UL-MU transmission for at least one STA. After receiving the trigger frame, the STA simultaneously transmits uplink data at a predetermined IFS time. The trigger frame can indicate the data transmission time of the uplink transmission STA and can inform the channel (or sub-channel) information allocated to the uplink transmission STA. When the AP sends the trigger frame, multiple STAs transmit uplink data through each allocated subcarrier at the time specified in the trigger frame. After completing the uplink data transmission, the AP sends an ACK to the STA that successfully transmitted 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-traditional wireless LAN systems, a specific number, such as 26, 52, or 106 tones, can be used as resource units (RUs) for subchannel-based access in a 20MHz 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), a partial AID, and a MAC address. Furthermore, the resource unit information includes the size and layout information of the resource unit.

[0080] Space reuse operation

[0081] Figure 7 The illustration depicts a channel access method using spatial reuse (SR) operation according to an embodiment of the present invention. Due to the proliferation of mobile devices and wireless communication systems, terminals are increasingly communicating in dense environments. Specifically, the number of cases where terminals communicate in environments with multiple overlapping network space service blocks (BSS) is increasing. When multiple BSSs overlap, the terminal's communication efficiency may decrease due to interference with other terminals. In particular, if a 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 address this problem, the terminal can perform SR operation.

[0082] More specifically, a terminal can determine whether a frame is an intra-BSS frame or an inter-BSS frame based on information used to identify the BSS of the received frame. The information used to identify the BSS includes at least one of BSS color, partial BSS color, partial AID, or MAC address. In embodiments of the invention, a non-traditional terminal may refer to a terminal conforming to the next-generation wireless LAN standard (i.e., IEEE 802.11ax). Furthermore, intra-BSS frames indicate frames transmitted from terminals belonging to the same BSS, and inter-BSS frames indicate frames transmitted from terminals belonging to an Overlapping BSS (OBSS) or another BSS.

[0083] According to embodiments of the present invention, a non-traditional 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. Furthermore, 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 embodiments of the present invention, the first and second operations can be configured in various ways.

[0084] According to an embodiment, depending on whether the received frame is an intra-BSS frame, the terminal can perform channel access based on different thresholds. 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 the CCA execution. On the other hand, when the received frame is determined to be an inter-BSS frame, the terminal can access the channel based on a second CCA threshold (i.e., a second operation or a 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 and second CCA thresholds. According to an embodiment of the 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 can have a value equal to or greater than the first CCA threshold.

[0085] According to another embodiment of the invention, the terminal can adjust the transmission power of the PHY Protocol Data Unit (PPDU) transmitted by the terminal based on 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 can adjust the transmission power of the PPDU based on the SR parameters extracted from the received frame (i.e., the second operation or SR operation). According to an embodiment, the terminal can increase the transmission power based on the SR parameters extracted from the received frame. According to an embodiment of the invention, non-traditional frames may contain an SR field for SR operations of the OBSS terminal, and specific embodiments 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 parameters.

[0086] refer to Figure 7 The transmitted non-traditional frames 310 and 320 may contain information indicating whether SR operation is permitted for the corresponding PPDU (i.e., information indicating whether SR is allowed). According to an embodiment, the information indicating whether SR is allowed can 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 bits of the SR field are 0), it can indicate that SR operation is not permitted. Figure 7 In this embodiment, the information included in the received first frame 310 indicating whether SR is allowed indicates that SR operation is permitted for the corresponding PPDU. Additionally, the information included in the received second frame 320 indicating whether SR is allowed indicates that SR operation is not permitted for the corresponding PPDU. 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. Additionally, the terminal checks for 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 allowed for the corresponding PPDU. Therefore, the terminal can perform SR operation according to the above embodiment. That is, the terminal can determine whether the channel is busy based on a first CCA threshold and a second CCA threshold. Furthermore, the terminal can adjust the transmission power based on the SR parameters extracted from the received frame 310.

[0088] Simultaneously, the terminal receiving the second frame 320 determines whether the received frame 320 is an intra-BSS frame or an inter-BSS frame. Additionally, the terminal checks for 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 for the corresponding PPDU is not allowed. Therefore, the terminal does not perform the SR operation according to the above 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 invention, information indicating whether SR is allowed can be transmitted via a conventional format frame. By including information indicating whether SR is allowed in a conventional format frame, the AP can protect transmitted conventional frames from SR operations by non-conventional terminals. According to an embodiment, the information indicating whether SR is allowed can be transmitted via an L-preamble. For example, the reserved bits of the L-SIG in the L-preamble can indicate whether SR is allowed. Alternatively, the guard subcarrier of the L-SIG in the L-preamble can carry information indicating whether SR is allowed.

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

[0091] Figure 8The illustration shows the SR operation of a terminal according to an embodiment of the present invention when a PPDU containing a trigger frame is sent in the OBSS. Figure 8 In this embodiment, BSS1 includes STA1 and STA2. In this case, STA1 is a non-AP STA and STA2 is an AP. Furthermore, BSS2 includes STA3 and STA4. In this case, STA3 is a non-AP STA and STA4 is an AP. Figure 8 In this embodiment, STA2 sends a trigger frame (or a PPDU containing the trigger frame) to STA1, and STA1 responds by sending an uplink PPDU. The uplink PPDU sent by STA1 can be a trigger-based PPDU. Simultaneously, STA3 of BSS2 intends to send a PPDU to STA4. Before transmitting the PPDU, STA3 can receive the trigger frame sent by STA2 and / or the trigger-based PPDU sent by STA1. In this case, STA3 can obtain the SR parameter from at least one of the trigger frame and the corresponding trigger-based PPDU.

[0092] According to an embodiment of the present invention, when sending a trigger frame, the AP can signal information about 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 can carry SR parameters (hereinafter referred to as SRP) through the trigger frame. According to an embodiment of the present invention, the SRP can be set 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. Additionally, "Acceptable Receiver Interference Level_AP" represents the level of interference that the AP sending the trigger frame can tolerate, i.e., the acceptable interference level. The acceptable interference level indicates the level of interference that the AP can tolerate when receiving a trigger-based PPDU in response to the trigger frame sent by the AP. Thus, the SRP can be determined based on the transmission power of the PPDU containing the trigger frame and the acceptable interference level. More specifically, the SRP can 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 invention, the AP can transmit the SRP determined by Equation 1 by inserting it into a trigger frame. According to an embodiment, the SRP can be included in the common information field of the trigger frame. The STA receiving the trigger frame from the AP transmits a multi-user uplink frame, i.e., a trigger-based PPDU in response. In this case, the STA can carry the SRP information obtained from the trigger frame through a predetermined field of the trigger-based PPDU. According to an embodiment, the SRP information can be included in the SR field of the HE-SIG-A of the trigger-based PPDU.

[0097] Simultaneously, the terminal receiving the trigger frame sent from the OBSS can perform SR operation based on the obtained SRP. In this case, the SRP can be obtained from at least one of the trigger frame and the corresponding trigger-based PPDU. According to an embodiment, the terminal can 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 transmitted by the terminal. Furthermore, "RSSI_TriggerFrame_at_STA" represents the received signal strength of the PPDU containing the trigger frame measured by the terminal. That is, the terminal's transmission power is set to a value 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 invention, the terminal can transmit the PPDU with the transmission power "TXPWR_STA" set according to Equation 2. Alternatively, the terminal can transmit the PPDU only if its expected transmission power "TXPWR_STA" 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 one embodiment, STA2 transmits the SRP by inserting it into the trigger frame. Additionally, STA1 transmits a trigger-based PPDU in response to the received trigger frame. In this case, STA1 can 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. Furthermore, STA3 can 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 invention, when the transmission power value of the PPDU that STA3 wants to transmit to STA4 is lower than the transmission power determined by Equation 2, STA3 can transmit the PPDU to STA4.

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

[0103] When a terminal receives radio signals, it can process the received signals separately at 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, the operation of the terminal's physical layer can be performed by the PHY Layer Management Entity (PLME). Additionally, the operation of the terminal's MAC layer can be performed by the MAC Layer Management Entity (MLME). In this case, for the above embodiment, the primitive's RXVECTOR may contain at least one of SRP (or SR field value), Transmission Opportunity (TXOP) duration, or BSS color.

[0104] Figure 9 A more detailed illustration shows the SR operation of a terminal according to an embodiment of the present invention when a PPDU containing a trigger frame is sent in the OBSS. See reference... Figure 8 As described, the terminal can transmit PPDUs according to SR operation based on the received signal strength of the PPDU containing the trigger frame sent from the OBSS and the obtained SRP value. Specifically, the terminal can transmit PPDUs by adjusting the transmission power based on the received signal strength of the PPDU containing the trigger frame sent from the OBSS and the SRP value indicated by the trigger frame and / or based on the triggered PPDU.

[0105] More specifically, the terminal can adjust the transmission power of the PPDU to be transmitted to satisfy Equation 2 as described above. In this case, the terminal can access the channel and transmit the PPDU by adjusting the transmission power when the SRP value is obtained. 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 a trigger frame sent from the OBSS. However, when the PPDU containing the trigger frame is a conventional PPDU, the terminal can decode the MAC frame of the corresponding PPDU to determine whether the PPDU contains a trigger frame. Furthermore, 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 illustrated embodiment, the terminal transmits the PPDU by adjusting the transmission power at the end of transmission of the PPDU containing the trigger frame sent from the OBSS. According to another specific embodiment, when the PPDU containing 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 sent from the OBSS. In these embodiments, the terminal can transmit the PPDU at a speed greater than that of the reference PPDU. Figure 8 The described embodiments send PPDUs based on SR operations at an earlier point in time.

[0107] Figure 10 The illustration shows an embodiment where a terminal performs SR operation based on a contention process when a PPDU containing a trigger frame is transmitted in the OBSS. As described above, during the transmission process of the 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] Simultaneously, one or more terminals may transmit PPDUs based on SR operations during the transmission process in OBSS. However, when multiple terminals transmit PPDUs based on SR operations, conflicts may occur between the transmissions of different terminals. Furthermore, when multiple terminals transmit PPDUs, interference exceeding the interference amplitude that the OBSS access point can tolerate may occur.

[0109] exist Figure 10 In this embodiment, BSS1 includes STA1 and STA2. In this case, STA1 is a non-AP STA, and STA2 is an AP STA. Furthermore, BSS2 includes STA3, STA4, and STA5. In this case, STA3 is a non-AP STA, STA4 is an AP STA, and STA5 is a non-AP STA. Additionally, BSS3 includes STA6, and STA6 is a non-AP STA. Figure 10 In this embodiment, STA2 sends a trigger frame (or a PPDU containing the trigger frame) to STA1, and STA1 responds by sending an uplink PPDU. The uplink PPDU sent by STA1 can be a trigger-based PPDU.

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

[0111] refer to Figure 10 If a PPDU is transmitted based on an SR operation, the terminal can perform the aforementioned backoff procedure. In this case, the terminal can use the backoff counter used when accessing the channel via DCF and EDCAF as the backoff counter value for the corresponding backoff procedure. According to an embodiment of the invention, to determine whether the channel is idle during the backoff procedure, the terminal can use energy detection (ED). According to another embodiment of the invention, the terminal can 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 can be a value greater than the existing minimum receiver sensitivity. For example, the terminal can determine whether the channel is idle based on the aforementioned OBSS PD level. According to an embodiment of the invention, the OBSS PD level used by the terminal in the SR operation can be set to a large value without any limitation. For example, the OBSS PD level used in the SR operation can be set to a predetermined value lower than an infinite value. During the transmission of a trigger-based PPDU of the OBSS, the terminal can perform the SR operation using the set OBSS PD level.

[0112] Figure 11 The illustration shows an example of a terminal setting the NAV when a PPDU containing a trigger frame is sent in the OBSS. If a PPDU containing a trigger frame is sent in the OBSS and the terminal is able to send the PPDU based on SR operations, the terminal may not set the NAV based on the trigger frame (or the PPDU containing the trigger frame). Conversely, if the terminal fails to receive a PPDU containing a trigger frame sent from the OBSS, the terminal cannot set the NAV based on the trigger frame.

[0113] When a terminal receives a trigger-based PPDU from the OBSS, the terminal can transmit the PPDU based on SR operation, as in the above embodiment. However, if the conditions for transmitting the PPDU based on SR operation are not met, the terminal can set the NAV based on the signaling field of the trigger-based PPDU. In this case, the signaling field can be the TXOP duration field of the HE-SIG-A field. If the conditions for transmitting the PPDU based on SR operation are not met, the terminal can perform CCA during the transmission of the trigger-based PPDU in the OBSS by using a value less than or equal to the first CCA threshold instead of the OBSS PD level set above (i.e., the second CCA). This is because the PPDU transmission based on the terminal's SR operation can generate interference greater than the magnitude of interference that the AP of the OBSS receiving the trigger-based PPDU can tolerate. Meanwhile, in Figure 11 In this embodiment, STA2 receives conventional preambles based on triggered PPDUs transmitted in the OBSS, but may not be able to receive non-traditional signaling fields. In this case, STA2 can perform CCA based on minimum receive sensitivity.

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

[0115] Figure 12 The illustration shows an embodiment of transmitting spatial reuse parameters via a trigger frame and a corresponding trigger-based PPDU. Figure 12 In one embodiment, the AP sends a trigger frame (or a PPDU containing the trigger frame) and receives a trigger-based PPDU sent by the STA.

[0116] As described above, the AP can send the SRP determined by Equation 1 by inserting it into the trigger frame. According to an embodiment, the SRP can be included in the common information field of the trigger frame. The STA receiving the trigger frame from the AP responds by sending a trigger-based PPDU. In this case, the STA can carry the SRP information obtained from the trigger frame through predetermined fields of the trigger-based PPDU. According to an embodiment, the SRP information can be included in the SR field of the HE-SIG-A of the trigger-based PPDU. That is, the SR field of the trigger-based PPDU can carry the SRP obtained from the trigger frame.

[0117] According to an embodiment of the present invention, the HE-SIG-A of the trigger-based PPDU may include 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 for a single subband comprising the total bandwidth for transmitting the trigger-based PPDU thereon. The total bandwidth for transmitting the trigger-based PPDU may be indicated by the bandwidth field of the HE-SIG-A of the trigger-based PPDU. (Reference) Figure 12 The HE-SIG-A based on the triggered PPDU can contain N SR fields. Each of the N SR fields can indicate the SRP of a single subband in units of 20MHz or 40MHz. According to an embodiment of the invention, N can be set to 4. That is, the multiple SR fields can include a first SR field, a second SR field, a third SR field, and a fourth SR field. However, the invention is not limited thereto. According to an embodiment, the multiple SR fields can respectively indicate the SRP for different subbands. However, according to an embodiment of the invention, under certain conditions, at least some of the multiple SR fields can be set to have the same value. Specific embodiments will be described later.

[0118] HE-format PPDUs transmit the same information in 20MHz bandwidth units for HE-SIG-A. That is, multiple SR fields of HE-SIG-A can be copied in 20MHz bandwidth units and carried within the total bandwidth of the triggered PPDU. Therefore, a terminal receiving triggered PPDUs can detect N SR fields corresponding to each subband.

[0119] The physical frequency band on which trigger-based PPDUs are transmitted can be identified using various information or combinations thereof. According to an embodiment, the physical frequency band on which trigger-based PPDUs are transmitted can be identified based on bandwidth field information and operation class information. The bandwidth field of the HE-SIG-A of the trigger-based PPDU indicates the total bandwidth on which the trigger-based PPDUs are transmitted. Additionally, the operation class information may include information about which frequency bands a particular frequency band can be combined with to configure a wideband channel. Therefore, a terminal receiving trigger-based PPDUs can identify the order of the subbands receiving the corresponding PPDUs within the total bandwidth based on the bandwidth field information and operation class information extracted from the received PPDUs. Furthermore, a terminal receiving trigger-based PPDUs can identify the SR field among multiple SR fields used to receive the corresponding PPDU based on the bandwidth field information and operation class information. Furthermore, although the method for identifying the physical frequency band on which trigger-based PPDUs are transmitted has been described above, the physical frequency band on which HE format PPDUs are transmitted can also be identified in the same manner.

[0120] According to another embodiment of the present invention, an HE format PPDU can be individually signal-transmitted with the physical frequency band information on which the corresponding PPDU is transmitted. For example, the HE-SIG-A of the HE PPDU can contain the physical frequency band information for transmitting the PPDU. More specifically, HE-SIG-A can indicate one or more frequency information for transmitting the physical frequency band information of the corresponding PPDU. For example, HE-SIG-A can indicate the starting frequency index of the frequency band on which the PPDU is transmitted. Additionally, when the total bandwidth of the transmitted PPDU is 80+80MHz or 160MHz, HE-SIG-A can indicate at least two frequency indices. According to yet another embodiment of the present invention, a PPDU in HE format can be signal-transmitted with the center frequency information of the physical frequency band on which the corresponding PPDU is transmitted. Additionally, when the total bandwidth of the transmitted PPDU is 80+80MHz or 160MHz, at least two center frequency information of the physical frequency band on which the PPDU is transmitted can be signal-transmitted.

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

[0122] According to embodiments of the present invention, the SR field can be adjusted based on the total bandwidth of the transmitted trigger-based PPDU. According to one 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 can indicate the SRP of a sub-band of a first frequency bandwidth. However, when the total bandwidth indicated by the bandwidth field exceeds the predetermined bandwidth, the SR field can indicate the SRP of a sub-band of a second frequency bandwidth wider than the first frequency bandwidth. For example, when the total bandwidth indicated by the bandwidth field is 20MHz, 40MHz, or 80MHz, the SR field can indicate the SRP of a 20MHz bandwidth sub-band. However, when the total bandwidth indicated by the bandwidth field is 80+80MHz or 160MHz, the SR field can indicate the SRP of a 40MHz bandwidth sub-band.

[0123] Figure 13 The illustration depicts a method for transmitting a trigger-based PPDU spatial reuse field using signals according to an embodiment of the present invention. (Reference) Figure 13The HE-SIG-A based on the triggered PPDU can contain multiple SR fields. According to an embodiment of the present invention, the HE-SIG-A based on the triggered PPDU can contain four SR fields. That is, the HE-SIG-A contains a first SR field, a second SR field, a third SR field, and a fourth SR field. Furthermore, each SR field can consist of 4 bits. Each SR field can indicate the SRP of a single subband in units of 20MHz or 40MHz.

[0124] First, when the total bandwidth of the triggered PPDU is 20MHz, the first SR field indicates the SRP of the corresponding 20MHz band. Additionally, the second, third, and fourth SR fields are set to the same value as the first SR field.

[0125] Next, when the total bandwidth for transmitting trigger-based PPDUs is 40MHz, the first SR field indicates the SRP of the first 20MHz band, and the second SR field indicates the SRP of the second 20MHz band. Additionally, 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 and second 20MHz bands constitute a total bandwidth of 40MHz, on which trigger-based PPDUs are transmitted.

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

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

[0128] According to embodiments of the present invention, multiple SR fields can indicate the SRPs of multiple sub-bands in physical frequency order. According to one embodiment, the multiple SR fields can indicate the SRPs of multiple sub-bands in ascending order of physical frequency. That is, the first SR field can indicate the SRP of the lowest frequency sub-band, and the fourth SR field can indicate the SRP of the highest frequency sub-band. According to another embodiment, the multiple SR fields can indicate the SRPs of multiple sub-bands in descending order of physical frequency. That is, the first SR field can indicate the SRP of the highest frequency sub-band, and the fourth SR field can indicate the SRP of the lowest frequency sub-band.

[0129] Figure 14 The illustration shows an embodiment of a method for setting the spatial reuse field of a trigger-based PPDU. As mentioned above, when the total bandwidth for transmitting trigger-based PPDUs is 160MHz (or 80+80MHz), each SR field of the trigger-based PPDU can indicate the SRP of a single subband in 40MHz units. Therefore, a method is needed to set the SRP of each subband in 40MHz units.

[0130] according to Figure 14 In one embodiment, 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 sub-band in 40MHz units, the resolution of the information in each sub-band 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 channels xa and xb are different, interference exceeding the acceptable interference level may occur at the channel with the worse condition in the two channels. Therefore, according to an embodiment of the invention, the SR field of the 40MHz band can be determined based on conservative values ​​in the SRP of the 20MHz sub-bands that make up the corresponding band.

[0131] According to an embodiment of the present invention, the SR field x of the xth 40MHz frequency band can 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, i.e., the xth SRP. Additionally, "SRP_xa" and "SRP_xb" represent the SRPs of the first and second 20MHz bands constituting the xth 40MHz band, respectively. "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. Furthermore, "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 the 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 20MHz band.

[0138] According to another embodiment of the present invention, the SR field x of the xth 40MHz frequency band can 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 as the sum of the transmission 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 “TXPWR_AP_xa” and “TXPWR_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 definitions of each variable in Equation 4 are as described in Equation 3.

[0145] According to another embodiment of the present invention, the SR field x of the xth 40MHz frequency band can 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 between "SRP_xa" and "SRP_xb". The calculation methods for "SRP_xa" and "SRP_xb" and the definition of each variable are described in Equation 3. According to the embodiment of Equation 5, without performing the operation of multiplying the SRP of the 20MHz band by 2, the terminal can identify in advance that "SRP_x" corresponds to the 20MHz band.

[0152] According to another embodiment of the present invention, the SR field x of the xth 40MHz frequency band can 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” can be set to the sum of “TX PWR_AP,x” and “Acceptable Receiver Interference Level_AP,x”. In this case, “TX PWR_AP,x” can be set to the minimum value among “TX PWR_AP_xa” and “TX_PWR_AP_xb”. Additionally, “Acceptable Receiver Interference Level_AP,x” can be set to the minimum value among “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 20MHz frequency band.

[0159] Figures 15 to 19 The illustration depicts a method for configuring HE-SIG-A and a space reuse field according to an embodiment of the present invention. Figures 15 to 19 In each embodiment shown, repeated descriptions of parts that are the same as or correspond to those in the embodiments of the previous figures will be omitted.

[0160] As described above, the HE-SIG-A for a triggered PPDU can contain four SR fields. When the total bandwidth for transmitting the triggered PPDU is 160MHz (or 80+80MHz), each SR field can indicate the SRP of a single subband in 40MHz units. In this case, the triggered PPDU can be transmitted on at least one of the primary 80MHz channel (hereinafter, the P80 channel) and the secondary 80MHz channel (hereinafter, the S80 channel). However, the OBSS terminal receiving the triggered PPDU cannot know the frequency band configuration of the BSS transmitting the corresponding PPDU. More specifically, when the total bandwidth for transmitting the triggered PPDU is 80+80MHz, the OBSS terminal may not be able to identify the physical frequency bands of the P80 and S80 channels that make up 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. Moreover, 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 identifier in OBSS terminals that receive trigger-based PPDUs.

[0161] Figure 15 The illustration depicts a method based on the HE-SIG-A of the triggered PPDU and the space reuse field, according to an embodiment of the present invention. Figure 15 In an embodiment, the HE-SIG-A of the HE format PPDU may include a location field. The location field may indicate a first or second frequency band comprising the total bandwidth. For example, when the total bandwidth of transmitted trigger-based PPDUs 410 and 420 is 80+80MHz, the location field of the HE-SIG-A may indicate a first 80MHz frequency band or a second 80MHz frequency band. According to an embodiment of the invention, the first and second SR fields of the HE-SIG-A may indicate the SRP of the first frequency band, and the third and fourth SR fields 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 using various methods. According to one embodiment, the first frequency band can be a low-frequency band, and the second frequency band can be a high-frequency band. According to another embodiment, the first frequency band can be a high-frequency band, and the second frequency band can be a low-frequency band. According to yet another embodiment, the first frequency band can be the frequency band of the P80 channel, and the second frequency band can be the frequency band of the S80 channel. Figure 15 In one embodiment, a trigger-based PPDU 410 transmitted on the first frequency band may have its position field set to 1 (or 0), and a trigger-based PPDU 420 transmitted on the second frequency band may have its position field set to 0 (or 1). In embodiments of the invention, the first and second frequency bands indicate different 80MHz frequency bands, but the invention is not limited thereto.

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

[0164] Figure 16 The illustration depicts a method for configuring a triggered PPDU based on HE-SIG-A and a space reuse field, according to another embodiment of the present invention. Figure 16 In one embodiment, when the total bandwidth of the triggered PPDUs 510 and 520 is 80+80MHz, the SR field of the first frequency band can be set to the same value as the SR field of the second frequency band.

[0165] As described above, the STA transmitting trigger-based PPDUs 510 and 520 can carry SRP information obtained from the trigger frame through the SR field of the trigger-based PPDUs 510 and 520. In this case, the STA can repeatedly insert two SRP information entries into the SR field. For example, the SRP information for each subband obtained from the trigger frame can be a, b, c, and d. a and b can be SRP information for the first frequency band, and c and d can be SRP information for the second frequency band. In this case, a, b, a, and b can be respectively included in the first to fourth SR fields of the trigger-based PPDU 510 transmitted on the first frequency band. Furthermore, c, d, c, and d can be respectively included in the first to fourth SR fields of the trigger-based PPDU 520 transmitted on the second frequency band. 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 can respectively indicate a high (or low) physical frequency band and a low (or high) physical frequency band. Alternatively, the first frequency band and the second frequency band can respectively indicate the frequency band of the P80 channel and the frequency band of the S80 channel.

[0166] The OBSS terminal receiving trigger-based PPDUs 510 and 520 obtains a first SRP from at least one of the first and third SR fields of the received PPDUs 510 and 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 in various rules. According to an embodiment, a and b can represent SRPs for low-frequency bands, and c and d can represent SRPs for high-frequency bands. According to another embodiment, a and b can represent SRPs for high-frequency bands, and c and d can represent SRPs for low-frequency bands. According to yet another embodiment, a and b can be set to the same values ​​as c and d, respectively.

[0167] Figure 17 The illustration depicts a method for configuring a triggered PPDU based on HE-SIG-A and a space reuse field, according to yet another embodiment of the present invention. Figure 17 In one embodiment, the SR field of the first frequency band and the SR field of the second frequency band can be identified by physical signaling methods.

[0168] More specifically, the cyclic shift value of the trigger-based PPDU 610 transmitted in the first frequency band can be set differently from the cyclic shift value of the trigger-based PPDU 620 transmitted in 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 can be pre-specified. Therefore, the OBSS terminal receiving the trigger-based PPDU 610 with the first cyclic shift value applied obtains the SRP information of the corresponding subband from at least one of the first SR field and the second SR field of the corresponding PPDU 610. Furthermore, the OBSS terminal receiving the trigger-based PPDU 620 with the second cyclic shift value 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 corresponding PPDU 620.

[0169] Figure 18 The illustration depicts a method for configuring a triggered PPDU based on HE-SIG-A and a space reuse field, according to yet another embodiment of the present invention. Figure 18 In one embodiment, the SR field of the first frequency band and the SR field of the second frequency band can be identified by physical signaling methods.

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

[0171] Therefore, the OBSS terminal receiving the RL-SIG using the first modulation scheme and the trigger-based PPDU 710 obtains the SRP information of the corresponding subband from at least one of the first SR field and the second SR field. Additionally, the OBSS terminal receiving the RL-SIG using the second modulation scheme and the trigger-based PPDU 720 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 The illustration depicts a method for configuring a triggered PPDU based on HE-SIG-A and a space reuse field, according to yet another embodiment of the present invention. Figure 19In one embodiment, the HE-SIG-A of the HE format PPDU may include a discontinuous band indicator, which indicates whether the total bandwidth of the transmitted PPDU is discontinuous. Therefore, the discontinuous band indicator can be used to identify whether the total bandwidth of the transmitted trigger-based PPDU is a continuous 160MHz or a discontinuous 80+80MHz.

[0173] An OBSS terminal receiving trigger-based PPDUs 810 and 820 can determine SR operation based on the discontinuous band indicator of the received PPDUs 810 and 820. If the discontinuous 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 that makes up the total bandwidth of the transmitted PPDU and its corresponding SR field. Therefore, the OBSS terminal can perform SR operation based on the obtained SR fields. However, as... Figure 19 As shown, if the discontinuous band indicator is set to 1 (i.e., if the total bandwidth of the transmitted PPDU is discontinuous), the OBSS terminal cannot identify each subband that makes up the total bandwidth of the transmitted PPDU and its corresponding SR field. Therefore, the OBSS terminal may not be able to perform the SR operation described above.

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

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

[0176] According to embodiments of the present invention, when the total bandwidth of the triggered PPDU transmission is a continuous frequency band (e.g., 80MHz, 160MHz, etc.), the physical frequency bands constituting the total bandwidth are determined by predetermined rules. Therefore, an OBSS terminal receiving a triggered PPDU transmitted on a continuous frequency band can identify the physical frequency band on which the triggered PPDU was transmitted. However, when the total bandwidth of the triggered PPDU transmission consists of non-contiguous frequency bands (e.g., 80+80MHz), the physical frequency bands constituting the total bandwidth may not be predetermined. Therefore, an OBSS terminal receiving a triggered PPDU transmitted on a non-contiguous frequency band cannot identify which frequency band the SR field of the corresponding PPDU is used for. More specifically, when the total bandwidth of the triggered PPDU transmission is 80+80MHz, the OBSS terminal cannot identify the set of SRPs (Screen Representations) of the subband from which the received PPDU is obtained within the first set of SR fields (i.e., at least one of the first SR field and the second SR field) and the second set of SR fields (i.e., at least one of the third SR field and the fourth SR field). Therefore, when transmitting trigger-based PPDUs on discontinuous frequency bands, a method is needed to resolve the ambiguity of the SR field identifier of the receiving OBSS terminal.

[0177] Figure 20 The diagram illustrates another embodiment of a method for resolving this problem by setting up a space reuse field based on a triggered PPDU. According to... Figure 20 In one embodiment, when the total bandwidth for transmitting trigger-based PPDUs is 80+80MHz, the representative values ​​in the SRPs for two corresponding 40MHz bands can be set as the SRPs for the respective bands. More specifically, the representative values ​​in the SRPs of the first and third 40MHz bands can be used as the first SRPs for the first and third 40MHz bands. Therefore, the first and third SR fields of the trigger-based PPDUs represent the same representative value. Similarly, the representative values ​​in the SRPs of the second and fourth 40MHz bands can be used as the second SRPs for the second and fourth 40MHz bands. Therefore, the second and fourth SR fields of the trigger-based PPDUs represent the same representative value. In this case, the first and second 40MHz bands constitute the first band for transmitting trigger-based PPDUs, and the third and fourth 40MHz bands constitute the second band for transmitting trigger-based PPDUs. According to an embodiment of the present invention, the smaller value among multiple SRPs can be set as the representative value of the corresponding SRP.

[0178] An OBSS terminal receiving a triggered PPDU with a total bandwidth of 80+80MHz 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. In other words, because the information indicated by the first and second SR fields is the same as that indicated by the third and fourth SR fields, the ambiguity of the SR field identification in the OBSS terminal can be resolved.

[0179] On the other hand, when the total bandwidth for transmitting trigger-based PPDUs is 160MHz, each SR field can indicate the SRP of different sub-bands in 40MHz units. That is, the first SR field indicates the SRP of the first 40MHz band, the second SR field indicates the SRP of the second 40MHz band, the third SR field indicates the SRP of the third 40MHz band, and the fourth SR field indicates the SRP of the fourth 40MHz band. In this case, the first 40MHz band to the fourth 40MHz band constitutes the total bandwidth of 160MHz for transmitting trigger-based PPDUs. Thus, by allowing the SR fields of trigger-based PPDUs transmitted on consecutive bands to indicate the SRP of each sub-band, SR operations more suitable for each sub-band can be performed.

[0180] Figure 21 This illustration shows yet another embodiment of a method for setting up and using a trigger-based PPDU space reuse field. According to... Figure 21 In one embodiment, each SR field of the triggered PPDU can indicate the SRP for different subbands, and the OBSS terminal receiving the PPDU can select the SRP for the SR operation of the corresponding subband from among the SRPs indicated by multiple SR fields.

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

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

[0183] Figure 22 The illustration depicts a method for configuring a triggered PPDU based on HE-SIG-A and a space reuse field, according to yet another embodiment of the present invention. Figure 22 In an embodiment, to address the ambiguity of the SR field identifier in the aforementioned OBSS terminal, SR operation can be restricted in trigger-based PPDUs transmitted on discontinuous frequency bands. More specifically, the SR field of trigger-based PPDUs 910 and 920 transmitted on the 80+80MHz frequency band can indicate a predetermined value that disallows SR operation. For this purpose, the AP can carry an SRP indicating the predetermined value that disallows SR operation via the trigger frame.

[0184] Figure 23 The illustration depicts a method for transmitting a space reuse field based on a trigger-based PPDU using signals, according to another embodiment of the present invention. Figure 23 In an embodiment, when the total bandwidth indicated by the bandwidth field of the trigger-based PPDU is 80+80MHz or 160MHz, the SR field can indicate the SRP for a subband with a 20MHz bandwidth. Figure 23 In the embodiments, when the total bandwidth for transmitting trigger-based PPDUs is 20MHz, 40MHz, or 80MHz, the value indicated by each SR field is compared with... Figure 13 The same as the one shown in the diagram.

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

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

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

[0188] According to embodiments of the present invention, as referenced above Figure 19 The HE-SIG-A of the HE format PPDU can contain a discontinuous band indicator. Therefore, the discontinuous band indicator can be used to identify whether the total bandwidth of the triggered PPDU being transmitted is a continuous 160MHz or a discontinuous 80+80MHz.

[0189] According to another embodiment of the invention, such as Figure 24 As shown, the total bandwidth of the PPDU can be signaled via the bandwidth field of HE-SIG-A to indicate whether it is continuous. More specifically, discontinuous bandwidth can be indicated via predetermined indices in the bandwidth field of HE-SIG-A. For example, indices 0, 1, 2, and 3 in the bandwidth field can represent 20MHz, 40MHz, 80MHz, and 160MHz, respectively. Additionally, index 4 in the bandwidth field can represent a discontinuous 80+80MHz. When the bandwidth field of the triggered PPDU indicates a continuous 160MHz, the OBSS terminal receiving the PPDU can perform a 160MHz SR operation. However, when the bandwidth field of the triggered PPDU indicates a discontinuous 80+80MHz, the OBSS terminal can perform an 80MHz SR operation, where 80MHz includes the subband receiving the corresponding PPDU.

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

[0191] Although the invention has been described using wireless LAN communication as an example, it is not limited thereto, and can be similarly applied to other communication systems, such as cellular communication, etc. Furthermore, while the methods, apparatus, and systems of the invention have been described in conjunction with specific embodiments, some or all of the components and operations of the invention can be implemented using a computer system with a general-purpose hardware architecture.

[0192] The embodiments described in the detailed description of the present invention can be implemented by various means. For example, embodiments of the present invention can be implemented by hardware, firmware, software, and / or combinations thereof.

[0193] In hardware implementation, the method according to embodiments 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 or software implementation, the method according to embodiments of the present invention can be implemented by modules, processes, functions, etc., that perform the operations described above. Software code can be stored in memory and operated by a processor. The processor can be equipped with memory internally or externally, and the memory can exchange data with the processor through various publicly known means.

[0195] The description of this invention is illustrative, and those skilled in the art will understand that the invention can be readily modified into other detailed forms without changing the technical concept or essential features. Therefore, it should be understood that the embodiments described above are intended to be illustrative in various senses and not restrictive. For example, each component described as a single type can be implemented as distributed, and similarly, components described as distributed can be implemented in an associated manner.

[0196] The scope of this invention is indicated by the claims to be described below, rather than by a detailed description, and it is to be understood that the meaning and scope of the claims and all variations or modifications derived from their equivalents fall within the scope of this 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, etc.

Claims

1. A wireless communication terminal, the terminal comprising: processor; and Communication unit, The processor is configured as follows: Receive trigger frames indicating uplink multi-user transmission, and Send trigger-based PHY protocol data units (PPDUs) that include multiple space reuse and bandwidth fields. The bandwidth field indicates the bandwidth related to the transmission and reception of the trigger-based PPDU, and The frequency bands to which the plurality of spatial reuse fields are applied, and the spatial reuse parameters of the plurality of spatial reuse fields, vary according to the configuration and size of the bandwidth indicated by the bandwidth field.

2. The wireless communication terminal according to claim 1, in, When the bandwidth indication is 20MHz, 40MHz, or 80MHz, the frequency band applying each of the plurality of spatial reuse fields is 20MHz, and Wherein, when the bandwidth indication is 160MHz or 80+80MHz, the frequency band applied to each of the plurality of spatial reuse fields is 40MHz.

3. The wireless communication terminal according to claim 1, in, When the bandwidth is indicated as 80+80MHz, the spatial multiplexing parameter for the first 80MHz of the bandwidth is set to the same value as the spatial multiplexing parameter for the second 80MHz of the bandwidth.

4. The wireless communication terminal according to claim 3, in, Each of the plurality of spatial reuse fields includes spatial reuse parameters for spatial reuse operations of the Overlapping Basic Service Set (OBSS) terminal.

5. The wireless communication terminal according to claim 4, 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. Wherein, the first space reuse field and the second space reuse field indicate the space reuse parameters of the first 80MHz. Wherein, the third space reuse field and the fourth space reuse field indicate the space reuse parameters of the second 80MHz, and Specifically, the first space reuse field and the third space reuse field are set to the same value as each other, and the second space reuse field and the fourth space reuse field are set to the same value as each other.

6. The wireless communication terminal according to claim 4, in, The space reuse operation is performed based on the received signal strength of the PPDU containing the trigger frame measured by the OBSS terminal and the space reuse parameters obtained by the OBSS terminal.

7. The wireless communication terminal according to claim 6, in, The space reuse operation includes adjusting the transmission power of the OBSS terminal based on the space reuse parameters, and The transmission power of the OBSS terminal is set to a value lower than that obtained by subtracting the received signal strength from the value of the spatial reuse parameter.

8. The wireless communication terminal according to claim 6, in, The space reuse operation includes allowing the OBSS terminal to transmit only when the expected transmission power of the OBSS terminal is lower than the value obtained by subtracting the received signal strength from the value of the space reuse parameter.

9. The wireless communication terminal according to claim 3, in, The spatial reuse parameters are set based on the transmission power of the PPDU containing the trigger frame and the acceptable interference level of the access point (AP) that sends the PPDU containing the trigger frame.

10. A wireless communication method for a wireless communication terminal, the method comprising: Receive trigger frames indicating uplink multi-user transmission, and Send trigger-based PHY protocol data units (PPDUs) that include multiple space reuse and bandwidth fields. The bandwidth field indicates the bandwidth related to the transmission and reception of the trigger-based PPDU, and The frequency bands to which the plurality of spatial reuse fields are applied, and the spatial reuse parameters of the plurality of spatial reuse fields, vary according to the configuration and size of the bandwidth indicated by the bandwidth field.

11. The wireless communication method according to claim 10, in, When the bandwidth indication is 20MHz, 40MHz, or 80MHz, the frequency band applying each of the plurality of spatial reuse fields is 20MHz, and Wherein, when the bandwidth indication is 160MHz or 80+80MHz, the frequency band applied to each of the plurality of spatial reuse fields is 40MHz.

12. The wireless communication method according to claim 10, in, When the bandwidth is indicated as 80+80MHz, the spatial multiplexing parameter for the first 80MHz of the bandwidth is set to the same value as the spatial multiplexing parameter for the second 80MHz of the bandwidth.

13. The wireless communication method according to claim 12, in, Each of the plurality of spatial reuse fields includes spatial reuse parameters for spatial reuse operations of the Overlapping Basic Service Set (OBSS) terminal.

14. The wireless communication method according to claim 13, 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. Wherein, the first space reuse field and the second space reuse field indicate the space reuse parameters of the first 80MHz. Wherein, the third space reuse field and the fourth space reuse field indicate the space reuse parameters of the second 80MHz, and Specifically, the first space reuse field and the third space reuse field are set to the same value as each other, and the second space reuse field and the fourth space reuse field are set to the same value as each other.

15. The wireless communication method according to claim 13, in, The space reuse operation is performed based on the received signal strength of the PPDU containing the trigger frame measured by the OBSS terminal and the space reuse parameters obtained by the OBSS terminal.

16. The wireless communication method according to claim 15, in, The space reuse operation includes adjusting the transmission power of the OBSS terminal based on the space reuse parameters, and The transmission power of the OBSS terminal is set to a value lower than that obtained by subtracting the received signal strength from the value of the spatial reuse parameter.

17. The wireless communication method according to claim 15, in, The space reuse operation includes allowing the OBSS terminal to transmit only when the expected transmission power of the OBSS terminal is lower than the value obtained by subtracting the received signal strength from the value of the space reuse parameter.

18. The wireless communication method according to claim 12, in, The spatial reuse parameters are set based on the transmission power of the PPDU containing the trigger frame and the acceptable interference level of the access point (AP) that sends the PPDU containing the trigger frame.

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