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 an overlapping basic service set (OBSS), and more particularly, to a wireless communication method and a wireless communication terminal for efficiently using wireless resources by supporting spatial reuse of an overlapping basic service set. 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 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 spatial reuse parameters for spatial reuse of an overlapping basic service set terminal.

Description

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

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

[0003] In recent years, with the expansion of the supply of mobile devices, wireless LAN technology that can provide fast wireless Internet services to mobile devices has been attracting attention. The wireless LAN technology allows mobile devices including smart phones, smart tablets, laptop computers, portable multimedia players, embedded devices, etc. to wirelessly access the Internet in a home or company or a specific service providing area based on short-range wireless communication technology.

[0004] Since the initial wireless LAN technology was supported using the 2.4 GHz frequency, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 has commercialized or developed various technical standards. First, IEEE 802.11b supports a maximum communication speed of 11 Mbps when using the frequency of the 2.4 GHz band. Compared with the significantly congested frequency of the 2.4 GHz band, IEEE 802.11a, which was commercialized after IEEE 802.11b, uses a frequency of the 5 GHz band instead of the 2.4 GHz band to reduce the impact of interference, and by using OFDM technology, increases the communication speed to a maximum of 54 Mbps. However, the disadvantage of IEEE 802.11a is that the communication distance is shorter than that of IEEE 802.11b. In addition, similar to IEEE 802.11b, IEEE 802.11g uses the frequency of the 2.4 GHz band to achieve a maximum communication speed of 54 Mbps and satisfies backward compatibility, which has attracted significant attention, and in terms of communication distance, it is superior to IEEE 802.11a.

[0005] In addition, as a technical standard established to overcome the communication speed limitations pointed out as a weakness in wireless LANs, IEEE 802.11n has been provided. IEEE 802.11n aims to increase the speed and reliability of the network and extend the working distance of the wireless network. More specifically, IEEE 802.11n supports High Throughput (HT), where the data processing speed is 540 Mbps or higher at maximum, and further, is based on Multiple Input and Multiple Output (MIMO) technology, where multiple antennas are used on both sides of the transmitting unit and the receiving unit to minimize transmission errors and optimize data speed. In addition, this standard can use an encoding scheme that transmits multiple overlapping copies in order to increase data reliability.

[0006] As wireless LANs are actively provided and, further, the applications using wireless LANs are diversified, the need for a new wireless LAN system that supports a higher throughput (Very High Throughput (VHT)) than the data processing speed supported by IEEE 802.11n has been drawing attention. Among them, IEEE 802.11ac supports a 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 the initial 11ac chipset even supports operation in the 2.4 GHz band for backward compatibility with existing 2.4 GHz band products. Theoretically, according to this standard, the wireless LAN speed of multiple stations can be enabled to reach at least 1 Gbps, and the maximum single-link speed can be enabled to reach at least 500 Mbps. This is achieved by expanding the concept of the wireless interface accepted by 802.11n, such as a wider wireless bandwidth (maximum 160 MHz), more MIMO spatial streams (maximum 8), multi-user MIMO, and high-density modulation (maximum 256QAM). In addition, as a scheme for transmitting data by using the 60 GHz band instead of the existing 2.4 GHz / 5 GHz bands, IEEE 802.11ad has been provided. IEEE 802.11ad is a transmission standard that provides a speed of up to 7 Gbps by using beamforming technology and is suitable for high-bitrate moving image streams such as massive data or uncompressed HD video. However, since the 60 GHz band has difficulty passing through obstacles, its disadvantage is that the 60 GHz band can only be used in devices in a short-distance space.

[0007] Meanwhile, in recent years, as the next-generation wireless LAN standard after 802.11ac and 802.11ad, discussions on providing an efficient and high-performance wireless LAN communication technology in a high-density environment have been continuously carried out. That is, in the next-generation wireless LAN environment, in the presence of high-density stations and access points (APs), it is necessary to provide communication with high spectral efficiency indoors / outdoors, and various technologies for realizing this communication are required. Summary of the Invention

[0008] Technical problem

[0009] An object of the present invention is to provide high-efficiency / high-performance wireless LAN communication in a high-density environment as described above.

[0010] An object of the present invention is to solve the ambiguity of the spatial reuse field identification of an inter-BSS (or overlapping BSS) terminal that receives a trigger-based PPDU.

[0011] An object of the present invention is to provide a wireless communication method and a wireless communication terminal in a high-density environment including overlapping basic service sets.

[0012] Technical solution

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

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

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

[0016] When the total bandwidth through which the trigger-based PPDU is transmitted is a discontinuous first frequency band and second frequency band, the spatial reuse parameters for the first frequency band and the spatial reuse parameters for the second frequency band may be set to the same value.

[0017] The high-efficiency signal field A (HE-SIG-A) of the trigger-based PPDU may include a plurality of spatial reuse fields, and the plurality of spatial reuse fields may carry spatial reuse parameters obtained from the trigger frame, and each of the plurality of spatial reuse fields may indicate the spatial reuse parameters for a single sub-band that constitutes the total bandwidth on which the trigger-based PPDU is transmitted.

[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 on which the transmission of a trigger-based PPDU is performed is a discontinuous first frequency band and second frequency band, the first spatial reuse field and the second spatial reuse field of the first frequency band may be respectively set to the same values as the third spatial reuse field and the fourth spatial reuse field for the second frequency band.

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

[0020] The spatial reuse parameters may be set based on the transmission power of the PPDU including the trigger frame and the acceptable interference level of the basic wireless communication terminal that transmits the PPDU including the trigger frame.

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

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

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

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

[0025] Advantageous Effects

[0026] According to an embodiment of the present invention, it is possible to solve the ambiguity of the spatial reuse field identification of an inter-BSS (or overlapping BSS) terminal that receives a trigger-based PPDU.

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

[0028] According to an embodiment of the present invention, it is possible to increase the total resource utilization rate in a contention-based channel access system and improve the performance of a wireless LAN system. Description of the Drawings

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

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

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

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

[0033] Figure 5 Schematically shows the process of setting up a link between a STA and an AP.

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

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

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

[0037] Figure 9 More specifically shows the SR operation of a terminal according to an embodiment of the present invention when transmitting a PPDU containing a trigger frame in an OBSS.

[0038] Figure 10 The figure shows an embodiment in which a terminal performs an SR operation based on a contention process when transmitting a PPDU containing a trigger frame in an OBSS.

[0039] Figure 11 The figure shows an embodiment of the operation in which a terminal sets a NAV when transmitting a PPDU containing a trigger frame in an OBSS.

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

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

[0042] Figure 14 The figure shows an embodiment of a method of setting a spatial reuse field of a trigger-based PPDU.

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

[0044] Figure 20 Illustrates another embodiment of a method for setting the spatial reuse field of a trigger-based PPDU.

[0045] Figure 21 Illustrates yet another embodiment of a method for setting and using the spatial reuse field of a trigger-based PPDU.

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

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

[0048] Figure 24 Illustrates a method for signaling the bandwidth field according to an embodiment of the present invention. Detailed Description

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

[0050] Throughout this specification and the following claims, when it describes that one element is "coupled" to another element, the element may be "directly coupled" to another element, or "electrically coupled" to another element via a third element. In addition, unless there is a clear contrary description, the words "comprising" and variations such as "including" or "includes" will be understood to implicitly include the stated elements, but do not exclude any other elements. In addition, limitations such as "or more" or "or less" based on a specific threshold may be appropriately replaced by "greater than" or "less than" respectively.

[0051] This application claims the priority and benefits of Korean Patent Applications Nos. 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 described in the corresponding applications that form the basis of the priority will be included in the detailed description of this application.

[0052] Figure 1 FIG. is a diagram of 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 with each other. Generally, a BSS can be divided into an infrastructure BSS and an independent BSS (IBSS), and Figure 1 FIG. illustrates the infrastructure BSS between them.

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

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

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

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

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

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

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

[0060] First, the communication unit 120 transmits and receives wireless signals, such as wireless LAN packets and the like, and can be embedded in the station 100 or provided as a peripheral device. 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 having different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. According to one embodiment, the station 100 may include a communication module using a frequency band of 6 GHz or higher and a communication module using a frequency band of 6 GHz or lower. The corresponding communication module may perform wireless communication with an AP or an 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 certain time or operate multiple communication modules together simultaneously according to the performance and requirements of the station 100. When the station 100 includes multiple communication modules, each communication module may be implemented by independent components, or multiple modules may be integrated into one chip. In an embodiment of the present invention, the communication unit 120 may represent a radio frequency (RF) communication module for processing RF signals.

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

[0062] Next, the display unit 150 outputs an image on the display screen. The display unit 150 may output various display objects, such as the content executed by the processor 110 or the user interface, etc., based on the control command of the processor 110. In addition, the memory 160 stores the control programs and various result data used in the station 100. The control programs may include access programs required for the station 100 to access an 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. In addition, the processor 110 can control each unit of the station 100 and control data transmission / reception among the units. According to an embodiment of the present invention, the processor 110 can execute a program for accessing an AP stored in the memory 160 and receive a communication configuration message sent by the AP. In addition, the processor 110 can read information about the priority conditions of the station 100 included in the communication configuration message 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 separately controlling certain components of the station 100, such as the communication unit 120 and the like. That is, the processor 110 can be a modem or a modulator / demodulator for modulating a wireless signal sent to the communication unit 120 and demodulating a wireless signal 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. Its detailed embodiments will be described below.

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

[0065] Figure 4 is a block diagram illustrating the configuration of an AP 200 according to an embodiment of the present invention. As illustrated in Figure 4 The AP 200 according to an embodiment of the present invention can include a processor 210, a communication unit 220, and a memory 260. In Figure 4 Among the components of the AP200, the parts that are the same as or correspond to the components of Figure 2 the station 100 of Figure 2 the station 100 will not be described repeatedly.

[0066] Refer to Figure 4 According to the present invention, the AP 200 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 the AP 200 may also include multiple communication modules using different frequency bands. That is, the AP 200 according to an embodiment of the present invention may include two or more communication modules among different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. Preferably, the AP 200 may include a communication module using a frequency band of 6 GHz or above and a communication module using a frequency band of 6 GHz or below. Each communication module may perform wireless communication with a station according to the wireless LAN standard of the frequency band supported by the corresponding communication module. The communication unit 220 may operate only one communication module at a certain time or operate multiple communication modules together simultaneously according to the performance and requirements of the AP 200. In an embodiment of the present invention, the communication unit 220 may represent a radio frequency (RF) communication module for processing RF signals.

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

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

[0069] Reference Figure 5 , generally, the link between the STA 100 and the AP 200 is set via three steps of scanning, authentication, and association. First, the scanning step is a step in which the STA 100 obtains access information of the BSS operated by the AP 200. Methods for performing scanning include a passive scanning method in which the AP 200 obtains information by using beacon messages (S101) sent periodically, and an active scanning method in which the STA 100 sends a probe request to the AP (S103) and obtains access information by receiving a probe response from the AP (S105).

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

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

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

[0073] A terminal performing wireless LAN communication checks whether the channel is busy by performing carrier sensing before transmitting data. When a wireless signal with a predetermined intensity or above is sensed, it is determined that the corresponding channel is busy, and the terminal delays access to the corresponding channel. Such a process is called Clear Channel Assessment (CCA), and the determination of whether the level of the corresponding signal is sensed is called the CCA threshold. When a wireless signal with a CCA threshold or above received by the terminal indicates that the corresponding terminal is a receiver, the terminal processes the received radio signal. Meanwhile, when no wireless signal is sensed in the corresponding channel, or a wireless signal with an intensity less than the CCA threshold is sensed, it is determined that the channel is idle.

[0074] When it is determined that the channel is idle, according to the situation of each terminal, after an Inter-Frame Space (IFS) time, such as Arbitration IFS (AIFS), PCF IFS (PIFS), etc. elapses, each terminal having data to transmit performs a backoff process. According to this embodiment, AIFS can be used as a component to replace the existing DCF IFS (DIFS). As long as a random number is determined by the corresponding terminal during the interval of the idle state of the channel, each terminal prepares as the slot time decreases, and the terminal that completely exhausts the slot attempts to access the corresponding channel. Thus, the interval during which each terminal performs the backoff process is called the contention window interval.

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

[0076] Multi-user transmission

[0077] When using orthogonal frequency division multiple access (OFDMA) or multiple input multiple output (MIMO), a wireless communication terminal can send data to multiple wireless communication terminals simultaneously. In addition, a wireless communication terminal can receive data from multiple wireless communication terminals simultaneously. For example, downlink multi-user (DL-MU) transmission in which an AP sends data to multiple STAs simultaneously, and uplink multi-user (UL-MU) transmission in which multiple STAs send data to the AP simultaneously 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 present invention, the UL-MU transmission process can be managed by the AP. UL-MU transmission can be performed in response to a trigger frame sent by the AP. The trigger frame indicates the UL-MU transmission of at least one STA. After receiving the trigger frame, the STAs send uplink data simultaneously at a predetermined IFS time. The trigger frame can indicate the data transmission time point of the uplink transmission STA and can notify the channel (or sub-channel) information assigned to the uplink transmission STA. When the AP sends a trigger frame, multiple STAs send uplink data through each assigned subcarrier at the time specified by the trigger frame. After completing the uplink data transmission, the AP sends an ACK to the STA that has successfully sent the uplink data. In this case, the AP can send a predetermined multi-STA block ACK (M-BA) as the ACK for multiple STAs.

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

[0080] Spatial reuse operation

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

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

[0083] According to an embodiment of the present invention, a non - traditional terminal can perform different operations depending on whether the received frame is an in - BSS frame. That is, when the received frame is determined to be an in - BSS frame, the terminal can perform a first operation. Additionally, when the received frame is determined to be an inter - BSS frame, the terminal can 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 can be an SR operation. According to an embodiment of the present invention, the first operation and the second operation can be set in various ways.

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

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

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

[0087] The terminal that receives the first frame 310 determines whether the received frame 310 is an in-BSS frame or an inter-BSS frame. Additionally, the terminal checks the information indicating whether SR is allowed 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 allowed indicates that SR operation for the corresponding PPDU is allowed. Thus, the terminal can perform the SR operation according to the above embodiments. That is, the terminal can determine whether the channel is busy based on the first CCA threshold and the second CCA threshold. Additionally, the terminal can adjust the transmission power based on the SR parameter extracted from the received frame 310.

[0088] Meanwhile, the terminal that receives the second frame 320 determines whether the received frame 320 is an in-BSS frame or an inter-BSS frame. Additionally, the terminal checks the information indicating whether SR is allowed 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 allowed indicates that SR operation for the corresponding PPDU is not allowed. Thus, the terminal does not perform the SR operation according to the above embodiments. 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. Additionally, the terminal does not perform transmission power adjustment based on the SR parameter extracted from the received frame 320.

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

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

[0091] Figure 8Illustrated is the SR operation of a terminal according to an embodiment of the present invention when transmitting a PPDU including a trigger frame in OBSS. In Figure 8 the embodiment of, BSS1 includes STA1 and STA2. In this case, STA1 is a non-AP STA and STA2 is an AP. In addition, BSS2 includes STA3 and STA4. In this case, STA3 is a non-AP STA, and STA4 is an AP. In Figure 8 the embodiment of, STA2 sends a trigger frame (or a PPDU including a trigger frame) to STA1, and STA1 sends an uplink PPDU in response thereto. The uplink PPDU sent by STA1 may be a trigger-based PPDU. Meanwhile, STA3 of BSS2 intends to send a PPDU to STA4. Before transmitting the PPDU, STA3 may receive the trigger frame sent by STA2 and / or the trigger-based PPDU sent by STA1. In this case, STA3 may obtain SR parameters 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 may signal information on at least one of the acceptable interference level of the AP and the transmission power of the PPDU including the trigger frame. More specifically, the AP may carry SR parameters (hereinafter referred to as SRP) through the trigger frame. According to an embodiment of the present invention, the SRP may 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 including the trigger frame. In addition, "acceptable receiver interference level_AP" represents the interference level that the AP sending the trigger frame can tolerate, that is, the acceptable interference level. The acceptable interference level may indicate the interference level that the AP can tolerate when receiving a trigger-based PPDU in response to the trigger frame sent by the AP. In this way, the SRP can be determined based on the transmission power of the PPDU including the trigger frame and the acceptable interference level. More specifically, the SRP may be set as the sum of the transmission power of the PPDU including the trigger frame and the acceptable interference level.

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

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

[0098] [Equation 2]

[0099] TXPWR_STA < SRP - RSSI_TriggerFrame_at_STA

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

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

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

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

[0104] Figure 9 Illustrate in more detail the SR operation of a terminal according to an embodiment of the present invention when transmitting a PPDU including a trigger frame in an OBSS. As referenced described, the terminal can transmit a PPDU according to the SR operation based on the received signal strength of the PPDU including the trigger frame sent from the OBSS and the obtained SRP value. Specifically, the terminal can transmit the PPDU by adjusting the transmission power based on the received signal strength of the PPDU including the trigger frame sent from the OBSS and the SRP value indicated by the trigger frame and / or the trigger-based 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 obtaining the SRP value. According to another embodiment, the terminal can start the transmission of the PPDU by adjusting the transmission power at the end of the transmission of the PPDU including the trigger frame sent from the OBSS. However, when the PPDU including the trigger frame is a legacy PPDU, the terminal can decode the MAC frame of the corresponding PPDU to determine whether the PPDU includes a trigger frame. Additionally, 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] In Figure 8In an embodiment, the illustrated terminal transmits a PPDU by adjusting the transmission power at the end of transmission of the PPDU including a trigger frame transmitted from an OBSS. According to another specific embodiment, when the PPDU including the trigger frame is a legacy PPDU, the terminal may transmit the PPDU by adjusting the transmission power when the terminal checks that the PPDU is a trigger frame transmitted from an OBSS. In these embodiments, the terminal may transmit a PPDU based on SR operation at an earlier time point than the embodiment Figure 9 described.

[0107] Figure 8 Illustrated is an embodiment in which the terminal performs an SR operation based on a contention process when transmitting a PPDU including a trigger frame in an OBSS. As described above, during the transmission process of the corresponding trigger-based PPDU and trigger frame in the OBSS, the terminal is capable of transmitting a PPDU based on SR operation. Specifically, the terminal may transmit a PPDU according to the condition of Equation 2. That is, the terminal may transmit a PPDU by adjusting the transmission power according to Equation 2.

[0108] Meanwhile, one or more terminals may transmit a PPDU based on SR operation during the transmission process in an OBSS. However, when multiple terminals transmit a PPDU based on SR operation, a collision may occur between the transmissions of different terminals. In addition, when multiple terminals transmit a PPDU, interference exceeding the interference level that the OBSS access point can tolerate may occur.

[0109] In Figure 10 the embodiment, BSS1 includes STA1 and STA2. In this case, STA1 is a non-AP STA, and STA2 is an AP. In addition, BSS2 includes STA3, STA4, and STA5. In this case, STA3 is a non-AP STA, STA4 is an AP, and STA5 is a non-AP STA. Additionally, BSS3 includes STA6, and STA6 is a non-AP STA. In Figure 10 the embodiment, STA2 transmits a trigger frame (or a PPDU including a trigger frame) to STA1, and STA1 transmits an uplink PPDU in response thereto. The uplink PPDU transmitted by STA1 may be a trigger-based PPDU.

[0110] In Figure 10 the embodiment, when at least two of STA3 to STA6 transmit a PPDU simultaneously, a collision may occur. Additionally, when at least two of STA3 to STA6 transmit a PPDU simultaneously, interference exceeding the interference level that STA2 can tolerate may occur. Therefore, STA2 may not receive the PPDU from STA1. To solve this problem, when performing PPDU transmission based on SR operation, the terminal may access the channel by performing a backoff process.

[0111] Reference Figure 10 , if a PPDU is sent based on the SR operation, the terminal can perform the above backoff process. In this case, the terminal can use the backoff counter used when accessing the channel through DCF and EDCAF as the backoff counter value for the corresponding backoff process. According to an embodiment of the present invention, in order to determine whether the channel is idle during the backoff process, the terminal can use energy detection (ED). According to another embodiment of the present invention, the terminal can determine whether the channel is idle according to 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 reception sensitivity. For example, the terminal can determine whether the channel is idle based on the above OBSS PD level. According to an embodiment of the present 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 the infinite value. During the transmission of the trigger-based PPDU of the OBSS, the terminal can use the set OBSS PD level to perform the SR operation.

[0112] Figure 10 An embodiment of the operation of the terminal setting the NAV when sending a PPDU containing a trigger frame in the OBSS is illustrated. If a PPDU containing a trigger frame is sent in the OBSS and the terminal is able to send a PPDU based on the SR operation, the terminal may not set the NAV according to the trigger frame (or the PPDU containing the trigger frame). Additionally, if the terminal fails to receive a PPDU containing the trigger frame sent from the OBSS, the terminal cannot set the NAV according to the trigger frame.

[0113] When the terminal receives a trigger-based PPDU sent from the OBSS, the terminal is able to send a PPDU based on the SR operation as in the above embodiment. However, if the condition for sending a PPDU based on the SR operation is 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 condition for sending a PPDU based on the SR operation is 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 above set OBSS PD level (i.e., the second CCA). This is because the PPDU transmission based on the SR operation of the terminal can generate interference with an amplitude greater than the interference that the AP receiving the trigger-based PPDU in the OBSS can tolerate. At the same time, in Figure 11 the embodiment, STA2 receives the legacy preamble of the trigger-based PPDU sent in the OBSS, but may not be able to receive the non-legacy signaling field. In this case, STA2 can perform CCA based on the minimum reception sensitivity.

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

[0115] Figure 11 FIG. illustrates an embodiment of transmitting spatial reuse parameters via a trigger frame and a corresponding trigger-based PPDU. In Figure 12 the embodiment, the AP transmits a trigger frame (or a PPDU including the trigger frame), and the receiving STA transmits a trigger-based PPDU.

[0116] As described above, the AP may transmit the SRP determined by Equation 1 by inserting it into the trigger frame. According to an embodiment, the SRP may be included in the common information field of the trigger frame. The STA that receives the trigger frame from the AP responds by transmitting a trigger-based PPDU. In this case, the STA may 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 may 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 may 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 of a single subband used to constitute the total bandwidth on which the trigger-based PPDU is transmitted. 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. Referring to Figure 12 , the HE-SIG-A of the trigger-based PPDU may include N SR fields. Each of the N SR fields may indicate the SRP of a single subband in units of 20 MHz or 40 MHz. According to an embodiment of the present invention, N may be set to 4. That is, the multiple SR fields may include a first SR field, a second SR field, a third SR field, and a fourth SR field. However, the present invention is not limited thereto. According to an embodiment, the multiple SR fields may respectively indicate the SRPs for different subbands. However, according to an embodiment of the present invention, under certain conditions, at least some of the multiple SR fields may be set to have the same value. Specific embodiments will be described later.

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

[0119] The physical frequency band on which the trigger-based PPDU is transmitted can be identified by various information or a combination thereof. According to an embodiment, the physical frequency band on which the trigger-based PPDU is 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 in which the trigger-based PPDU is transmitted. Additionally, the operation class information can include information about which frequency bands can be combined with a specific frequency band to configure a wideband channel. Therefore, a terminal receiving the trigger-based PPDU can identify the order of the sub-bands in the total bandwidth in which the corresponding PPDU is received based on the bandwidth field information and operation class information extracted from the received PPDU. Additionally, a terminal receiving the trigger-based PPDU can identify the SR field of the frequency band used to receive the corresponding PPDU among the multiple SR fields based on the bandwidth field information and operation class information. Meanwhile, although the method of identifying the physical frequency band on which the trigger-based PPDU is transmitted has been described above, the physical frequency band on which the HE format PPDU is transmitted can also be identified in the same manner.

[0120] According to another embodiment of the present invention, the HE format PPDU can signal the physical frequency band information on which the corresponding PPDU is transmitted separately. For example, the HE-SIG-A of the HE PPDU can contain the physical frequency band information of the transmitted PPDU. More specifically, the HE-SIG-A can indicate one or more frequency information of the physical frequency band on which the corresponding PPDU is transmitted. For example, the 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 + 80 MHz or 160 MHz, the HE-SIG-A can indicate at least two frequency indices. According to still another embodiment of the present invention, the PPDU in the HE format can signal 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 + 80 MHz or 160 MHz, at least two center frequency information of the physical frequency band on which the PPDU is transmitted can be signaled.

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

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

[0123] Figure 12 FIG. illustrates a method of signaling the spatial reuse field of a triggered PPDU according to an embodiment of the present invention. Refer to Figure 13, the HE-SIG-A of the trigger-based PPDU may include multiple SR fields. According to an embodiment of the present invention, the HE-SIG-A of the trigger-based PPDU may include four SR fields. That is, the HE-SIG-A includes a first SR field, a second SR field, a third SR field, and a fourth SR field. Moreover, each SR field may be composed of 4 bits. Each SR field may indicate the SRP of a single sub-band in units of 20 MHz or 40 MHz.

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

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

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

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

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

[0129] Figure 13 An embodiment of a method for setting the spatial reuse field of a trigger-based PPDU is illustrated. As described above, when the total bandwidth of the trigger-based PPDU to be transmitted is 160 MHz (or 80 + 80 MHz), each SR field of the trigger-based PPDU may indicate the SRP of a single sub-band in units of 40 MHz. Therefore, a method for setting the SRP of each sub-band in units of 40 MHz is required.

[0130] According to Figure 14 an embodiment, the SR field x of the x-th 40 MHz band may be determined by reflecting the SRP of the 20 MHz channel xa and the SRP of the 20 MHz channel xb (where x = 1, 2, 3, or 4). If the SR field indicates the SRP of a sub-band in units of 40 MHz, the resolution of the information of 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 situations of the channel xa and the channel xb are different, interference exceeding the acceptable interference level may occur at the channel in the difference situation between the two channels. Therefore, according to an embodiment of the present invention, the SR field of the 40 MHz band may be determined based on the conservative value among the SRPs of the 20 MHz sub-bands constituting the corresponding band.

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

[0132] [Equation 3]

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

[0134] where

[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 x-th SRP. Additionally, "SRP_xa" and "SRP_xb" respectively represent the SRPs of the first 20 MHz band and the second 20 MHz band that make up the x-th 40 MHz band. "SRP_xa" can be set to the sum of the transmission power "TX PWR_AP,xa" of the PPDU containing the trigger frame on channel xa and the acceptable interference level "Acceptable Receiver Interference Level_AP,xa" in channel xa. Moreover, "SRP_xb" can be set to the sum of the transmission power "TX PWR_AP,xb" of the PPDU containing the trigger frame on channel xb and the acceptable interference level "Acceptable Receiver Interference Level_AP,xb" in channel xb. That is, according to the embodiment of Equation 3, the SR field x can be set to twice the minimum of "SRP_xa" and "SRP_xb" for the corresponding 20 MHz bands.

[0138] According to another embodiment of the present invention, the SR field x of the x-th 40 MHz 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] Where

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

[0143] Acceptable Receiver Interference Level_AP,x = 2 * min(Acceptable Receiver Interference Level_AP,xa, Acceptable Receiver Interference Level_AP,xb)

[0144] Referring to Equation 4, "SRP_x" can be set to the sum of the 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 "TX PWR_AP_xa" and "TX_PWR_AP_xb". Additionally, "Acceptable Receiver Interference Level_AP,x" can be set to twice the minimum of "Acceptable Receiver Interference Level_AP,xa" and "Acceptable Receiver Interference Level_AP,xb". The definitions of each variable in Equation 4 are as described in Equation 3.

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

[0146] [Equation 5]

[0147] SRP_x = min(SRP_xa, SRP_xb)

[0148] where

[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 of "SRP_xa" and "SRP_xb". The calculation methods of "SRP_xa" and "SRP_xb" and the definition of each variable are as described in Equation 3. According to the embodiment of Equation 5, without performing the operation of multiplying the SRP of the 20 MHz band by 2, the terminal can identify in advance that "SRP_x" corresponds to the 20 MHz band.

[0152] According to another embodiment of the present invention, the SR field x of the x-th 40 MHz 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] where

[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 of "TX PWR_AP_xa" and "TX_PWR_AP_xb". Additionally, "Acceptable Receiver Interference Level_AP, x" can be set to the minimum of "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 identify in advance that "SRP_x" corresponds to the 20 MHz band.

[0159] Figure 14 FIG. illustrates a method of configuring HE-SIG-A and spatial reuse fields according to an embodiment of the present invention. In Figures 15 to 19 each of the embodiments shown, a repeated description of parts that are the same as or corresponding to those of the embodiments of the previous figures will be omitted.

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

[0161] Figures 15 to 19 FIG. illustrates a method of configuring HE-SIG-A and spatial reuse fields of a triggered PPDU according to an embodiment of the present invention. According to Figure 15 the embodiment, the HE-SIG-A of a PPDU in HE format may include a position field. The position field may indicate the first frequency band or the second frequency band that makes up the total bandwidth. For example, when the total bandwidth of the triggered PPDUs 410 and 420 being transmitted is 80 + 80 MHz, the position field of the HE-SIG-A may indicate the first 80 MHz frequency band or the second 80 MHz frequency band. According to an embodiment of the present invention, the first SR field and the second SR field of the HE-SIG-A may indicate the SRP of the first frequency band, and the third SR field and the fourth SR field of the HE-SIG-A may indicate the SRP of the second frequency band.

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

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

[0164] Figure 15 Illustrates a method of configuring the HE-SIG-A and spatial reuse fields of a trigger-based PPDU according to another embodiment of the present invention. According to Figure 16 the embodiment of, when the total bandwidth of transmitting the trigger-based PPDUs 510 and 520 is 80 + 80 MHz, the SR field of the first frequency band may be set to the same value as the SR field of the second frequency band.

[0165] As described above, the STA that transmits the trigger-based PPDUs 510 and 520 can carry the SRP information obtained from the trigger frame through the SR fields of the trigger-based PPDUs 510 and 520. In this case, the STA can repeatedly insert two pieces of SRP information into the SR field. For example, the SRP information for each sub-band obtained from the trigger frame can be a, b, c, and d. a and b can be the SRP information for the first frequency band, and c and d can be the SRP information for the second frequency band. In this case, a, b, a, and b can be included in the first SR field to the fourth SR field of the trigger-based PPDU 510 transmitted on the first frequency band, respectively. In addition, c, d, c, and d can be included in the first SR field to the fourth SR field of the trigger-based PPDU 520 transmitted on the second frequency band, respectively. That is, the first SR field and the second SR field of the first frequency band are respectively set to the same values as the third SR field and the fourth SR field of the second frequency band. As described above, the first frequency band and the second frequency band can respectively indicate the high (or low) physical frequency band and the 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 that receives the trigger-based PPDUs 510 and 520 obtains the first SRP from at least one of the first SR field and the third SR field of the received PPDUs 510 and 520. That is, since the information indicated by the first SR field and the second SR field is the same as the information indicated by the third SR field and the fourth SR field, 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 transmitted by the trigger frame can be set in various rules. According to an embodiment, a and b can represent the SRP for the low frequency band, and c and d can represent the SRP for the high frequency band. According to another embodiment, a and b can represent the SRP for the high frequency band, and c and d can represent the SRP for the low frequency band. According to still another embodiment, a and b can be respectively set to the same values as c and d.

[0167] Figure 16 FIG. illustrates a method of configuring the HE-SIG-A and the spatial reuse field of a trigger-based PPDU according to still another embodiment of the present invention. According to Figure 17 the embodiment, the SR field of the first frequency band and the SR field of the second frequency band can be identified by a physical signaling method.

[0168] More specifically, the cyclic shift value of the trigger-based PPDU 610 transmitted on the first frequency band can be set differently from the cyclic shift value of the trigger-based PPDU 620 transmitted on the second frequency band. In this case, the first cyclic shift value applied to the first frequency band and the second cyclic shift value applied to the second frequency band can be specified in advance. Therefore, an OBSS terminal receiving the trigger-based PPDU 610 applying the first cyclic shift value obtains the SRP information of the corresponding sub-band from at least one of the first SR field and the second SR field of the corresponding PPDU 610. In addition, an OBSS terminal receiving the trigger-based PPDU 620 applying the second cyclic shift value obtains the SRP information of the corresponding sub-band from at least one of the third SR field and the fourth SR field of the corresponding PPDU 620.

[0169] Figure 17 FIG. illustrates a method of configuring the HE-SIG-A and the spatial reuse field of a trigger-based PPDU according to another embodiment of the present invention. According to Figure 18 the embodiment, the SR field of the first frequency band and the SR field of the second frequency band can be identified by a physical signaling method.

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

[0171] Therefore, an OBSS terminal receiving the trigger-based PPDU710 including the RL-SIG applying the first modulation scheme obtains the SRP information of the corresponding sub-band from at least one of the first SR field and the second SR field. Additionally, an OBSS terminal receiving the trigger-based PPDU 720 including the RL-SIG applying the second modulation scheme obtains the SRP information of the corresponding sub-band from at least one of the third SR field and the fourth SR field of the PPDU 720.

[0172] Figure 18 FIG. illustrates a method of configuring the HE-SIG-A and the spatial reuse field of a trigger-based PPDU according to another embodiment of the present invention. According to Figure 19In an embodiment, the HE-SIG-A of a PPDU in HE format may include a discontinuous band indicator that indicates whether the total bandwidth for transmitting the PPDU is discontinuous. Therefore, it is possible to identify whether the total bandwidth for transmitting a trigger-based PPDU is continuous 160 MHz or discontinuous 80 + 80 MHz through the discontinuous band indicator.

[0173] An OBSS terminal receiving trigger-based PPDUs 810, 820 may determine an SR operation based on the discontinuous band indicator of the received PPDUs 810, 820. If the discontinuous band indicator is set to 0 (i.e., if the total bandwidth for transmitting the 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 may perform an SR operation based on the obtained SR field. However, as Figure 19 shown, if the discontinuous band indicator is set to 1 (i.e., if the total bandwidth for transmitting the 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 above SR operation.

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

[0175] Figure 19 and 21 FIG. illustrates another embodiment of a method for setting a spatial reuse field of a trigger-based PPDU. As described above, when the total bandwidth for transmitting a trigger-based PPDU is 160 MHz (or 80 + 80 MHz), each SR field of the trigger-based PPDU may indicate an SRP for each subband in units of 40 MHz.

[0176] According to an embodiment of the present invention, when the total bandwidth of a trigger-based PPDU is a continuous frequency band (e.g., 80 MHz, 160 MHz, etc.), the physical frequency bands that make up the total bandwidth are determined by a predetermined rule. Therefore, an OBSS terminal receiving a trigger-based PPDU transmitted on a continuous frequency band can identify the physical frequency band on which the trigger-based PPDU is transmitted. However, when the total bandwidth of a trigger-based PPDU is composed of non-continuous frequency bands (e.g., 80 + 80 MHz), the physical frequency bands that make up the total bandwidth may not be predetermined. Therefore, an OBSS terminal receiving a trigger-based PPDU transmitted on a non-continuous frequency band cannot identify for which frequency band the SR field of the corresponding PPDU is used. More specifically, when the total bandwidth of a trigger-based PPDU is 80 + 80 MHz, the OBSS terminal cannot identify the set of SRPs among 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) that can obtain the sub-band of the received PPDU. Therefore, when a trigger-based PPDU is transmitted on a non-continuous frequency band, a method for resolving the ambiguity of the SR field identification of the receiving OBSS terminal is required.

[0177] Figure 20 FIG. illustrates another embodiment of a method for setting the spatial reuse field of a trigger-based PPDU to facilitate solving this problem. According to Figure 20 the embodiment, when the total bandwidth of a trigger-based PPDU is 80 + 80 MHz, the representative value among the SRPs for two corresponding 40 MHz frequency bands can be set as the SRP for the corresponding frequency band. More specifically, the representative value among the SRPs of the first 40 MHz frequency band and the third 40 MHz frequency band can be used as the first SRP for the first 40 MHz frequency band and the third 40 MHz frequency band. Therefore, the first SR field and the third SR field of the trigger-based PPDU represent the same representative value. Similarly, the representative value among the SRPs of the second 40 MHz frequency band and the fourth 40 MHz frequency band can be used as the second SRP for the second 40 MHz frequency band and the fourth 40 MHz frequency band. Therefore, the second SR field and the fourth SR field of the trigger-based PPDU represent the same representative value. In this case, the first 40 MHz frequency band and the second 40 MHz frequency band constitute the first frequency band on which the trigger-based PPDU is transmitted, and the third 40 MHz frequency band and the fourth 40 MHz frequency band constitute the second frequency band on which the trigger-based PPDU is transmitted. 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 that receives a trigger-based PPDU with a total bandwidth of 80 + 80 MHz can obtain a first SRP from at least one of the first SR field and the third SR field of the received PPDU, and can obtain a second SRP from at least one of the second SR field and the fourth SR field of the received PPDU. That is, since the information indicated by the first SR field and the second SR field is the same as the information indicated by the third SR field and the fourth SR field, the ambiguity of the SR field identification of the OBSS terminal can be resolved.

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

[0180] Figure 20 FIG. illustrates another embodiment of a method for setting and using the spatial reuse field of a trigger-based PPDU. According to Figure 21 the embodiment, each SR field of the trigger-based PPDU can indicate the SRP for different sub-bands, and an OBSS terminal that receives the PPDU can select, among the SRPs indicated by multiple SR fields, the SRP for the SR operation of the corresponding sub-band.

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

[0182] OBSS terminals that receive trigger-based PPDUs with a total bandwidth of 80 + 80 MHz use the smaller value between two corresponding SR fields as the SRP for the respective subbands. That is, the smaller value between the first SR field value and the third SR field value is used for the SRP of the first 40 MHz band and / or the third 40 MHz band. Additionally, the smaller value between the second SR field value and the fourth SR field value is used for the SRP of the second 40 MHz band and / or the fourth 40 MHz band.

[0183] Figure 21 FIG. illustrates a method of configuring the HE-SIG-A and spatial reuse fields of a trigger-based PPDU according to another embodiment of the present invention. According to Figure 22 the embodiment, to solve the ambiguity of the SR field identification of the above OBSS terminals, SR operations can be restricted in trigger-based PPDUs transmitted on non-contiguous frequency bands. More specifically, the SR fields of trigger-based PPDUs 910, 920 transmitted on an 80 + 80 MHz band can indicate a predetermined value that does not allow SR operations. To this end, the AP can carry an SRP indicating a predetermined value that does not allow SR operations through a trigger frame.

[0184] Figure 22 FIG. illustrates a method of signaling the spatial reuse field of a trigger-based PPDU according to another embodiment of the present invention. According to Figure 23 the embodiment, when the total bandwidth indicated by the bandwidth field of the trigger-based PPDU is 80 + 80 MHz or 160 MHz, the SR field can indicate the SRP for subbands with a 20 MHz bandwidth. In Figure 23 the embodiment, when the total bandwidth of the transmitted trigger-based PPDU is 20 MHz, 40 MHz, or 80 MHz, the values indicated by each SR field are the same as those illustrated in Figure 23 .

[0185] According to Figure 13 the embodiment, when the total bandwidth of the transmitted trigger-based PPDU is 160 MHz (or 80 + 80 MHz), the value of the SR field of the first 80 MHz band can be set to be different from the value of the SR field of the second 80 MHz band. That is, the first SR field to the fourth SR field of the trigger-based PPDU transmitted on the first band respectively indicate the SRP of the first 20 MHz band to the fourth 20 MHz band of the first band. Additionally, the first SR field to the fourth SR field of the trigger-based PPDU transmitted on the second band respectively indicate the SRP of the first 20 MHz band to the fourth 20 MHz band of the second band. In this case, the first SR field to the fourth SR field of the first band and the first SR field to the fourth SR field of the second band can be determined independently of each other.

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

[0187] Figure 23 FIG. illustrates a method of signaling a bandwidth field according to an embodiment of the present invention. In the above embodiment, it is necessary to identify whether the total bandwidth of the trigger-based PPDU being transmitted is a continuous 160 MHz or a discontinuous 80 + 80 MHz. According to an embodiment of the present invention, it is possible to signal via the HE-SIG-A whether the total bandwidth of the PPDU is continuous.

[0188] According to an embodiment of the present invention, as referred to above Figure 24 As described, the HE-SIG-A of the HE format PPDU may include a discontinuous band indicator. Thus, it is possible to identify whether the total bandwidth of the trigger-based PPDU being transmitted is a continuous 160 MHz or a discontinuous 80 + 80 MHz through the discontinuous band indicator.

[0189] According to another embodiment of the present invention, as Figure 19 Figure 24 shown, it is possible to signal whether the total bandwidth of the PPDU is continuous through the bandwidth field of the HE-SIG-A. More specifically, a discontinuous bandwidth can be indicated via a predetermined index of the bandwidth field of the HE-SIG-A. For example, indexes 0, 1, 2, and 3 of the bandwidth field may represent 20 MHz, 40 MHz, 80 MHz, and 160 MHz, respectively. Additionally, index 4 of the bandwidth field may represent a discontinuous 80 + 80 MHz. When the bandwidth field of the trigger-based PPDU indicates a continuous 160 MHz, the OBSS terminal receiving the PPDU can perform SR operations for 160 MHz. However, when the bandwidth field of the trigger-based PPDU indicates a discontinuous 80 + 80 MHz, the OBSS terminal can perform SR operations for 80 MHz, which includes the sub-band where the corresponding PPDU is received.

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

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

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

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

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

[0195] The description of the present invention is illustrative, and those skilled in the art will be able to understand that the present invention can be easily modified into other detailed forms without changing the technical idea or its essential features. Therefore, it should be understood that the embodiments described above are illustrative in every sense and not restrictive. For example, each component described as a single type can be implemented distributively, and similarly, components described as distributed can also be implemented in an associated form.

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

[0197] Industrial applicability

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

Claims

1. A wireless communication terminal, the terminal comprising: a processor; and a communication unit, wherein, the processor is configured to: receive a trigger frame indicating uplink multi-user transmission, and send a trigger-based PHY protocol data unit (PPDU) in response to the trigger frame, wherein, the trigger-based PPDU includes spatial reuse parameters for spatial reuse operations of an overlapping basic service set (OBSS) terminal, and the spatial reuse parameters are carried via a first spatial reuse field, a second spatial reuse field, a third spatial reuse field, and a fourth spatial reuse field included in an efficient signal field A (HE-SIG-A) of the trigger-based PPDU, and when the total bandwidth indicated by the bandwidth field of the HE-SIG-A of the trigger-based PPDU includes a first frequency band and a second frequency band that are non-consecutive with each other: wherein, the first spatial reuse field indicates a first spatial reuse parameter for the first frequency band in the spatial reuse parameters; wherein, the second spatial reuse field indicates a second spatial reuse parameter for the first frequency band in the spatial reuse parameters; wherein, the third spatial reuse field indicates the first spatial reuse parameter for the second frequency band in the spatial reuse parameters; wherein, the fourth spatial reuse field indicates the second spatial reuse parameter for the second frequency band in the spatial reuse parameters, and wherein, both the first spatial reuse field and the third spatial reuse field are set to a first value, and both the second spatial reuse field and the fourth spatial reuse field are set to a second value.

2. The wireless communication terminal according to claim 1, Among them, the first spatial reuse field is applied to a first sub-band constituting the total bandwidth; wherein, the second spatial reuse field is applied to a second sub-band constituting the total bandwidth; wherein, the third spatial reuse field is applied to a third sub-band constituting the total bandwidth; wherein, the fourth spatial reuse field is applied to a fourth sub-band constituting the total bandwidth.

3. The wireless communication terminal according to claim 1, Among them, the spatial reuse fields included in the trigger-based PPDU carry the spatial reuse parameters obtained from the trigger frame.

4. The wireless communication terminal according to claim 1, Among them, the spatial reuse parameters are set based on the transmission power of the PPDU including the trigger frame and the acceptable interference level of the basic wireless communication terminal that sends the PPDU including the trigger frame.

5. The wireless communication terminal according to claim 1, Among them, the spatial reuse operation is performed based on the received signal strength of the PPDU including the trigger frame measured by the OBSS terminal and the spatial reuse parameters obtained by the OBSS terminal.

6. The wireless communication terminal according to claim 5, Among them, the spatial reuse operation includes an operation of adjusting the transmission power of the OBSS terminal based on the spatial reuse parameters, and wherein, the transmission power of the OBSS terminal is set to be lower than the value obtained by subtracting the received signal strength from the value of the spatial reuse parameters.

7. The wireless communication terminal according to claim 5, Among them, wherein the spatial reuse operation includes allowing transmission of the OBSS terminal only when the expected transmission power of the OBSS terminal is lower than a value obtained by subtracting the received signal strength from the value of the spatial reuse parameter.

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

9. A wireless communication method for a wireless communication terminal, the method comprising: receiving a trigger frame indicating uplink multi-user transmission; sending a trigger-based PHY protocol data unit (PPDU) in response to the trigger frame, wherein the trigger-based PPDU includes a spatial reuse parameter for spatial reuse operation of an overlapping basic service set (OBSS) terminal, and the spatial reuse parameter is carried via a first spatial reuse field, a second spatial reuse field, a third spatial reuse field, and a fourth spatial reuse field included in the high efficiency signal field A (HE-SIG-A) of the trigger-based PPDU, and when the total bandwidth indicated by the bandwidth field of the HE-SIG-A of the trigger-based PPDU includes a first frequency band and a second frequency band that are non-consecutive from each other: wherein the first spatial reuse field indicates a first spatial reuse parameter in the spatial reuse parameter for the first frequency band; wherein the second spatial reuse field indicates a second spatial reuse parameter in the spatial reuse parameter for the first frequency band; wherein the third spatial reuse field indicates the first spatial reuse parameter in the spatial reuse parameter for the second frequency band; wherein the fourth spatial reuse field indicates a second spatial reuse parameter in the spatial reuse parameter for the second frequency band, and wherein both the first spatial reuse field and the third spatial reuse field are set to a first value, and both the second spatial reuse field and the fourth spatial reuse field are set to a second value.

10. The wireless communication method according to claim 9, Among them, wherein the first spatial reuse field is applied to a first sub-band constituting the total bandwidth; wherein the second spatial reuse field is applied to a second sub-band constituting the total bandwidth; wherein the third spatial reuse field is applied to a third sub-band constituting the total bandwidth; wherein the fourth spatial reuse field is applied to a fourth sub-band constituting the total bandwidth.

11. The wireless communication method according to claim 9, Among them, including that the spatial reuse field included in the trigger-based PPDU carries the spatial reuse parameter obtained from the trigger frame.

12. The wireless communication method according to claim 9, Among them, setting the spatial reuse parameter based on the transmission power of the PPDU including the trigger frame and the acceptable interference level of the basic wireless communication terminal that sends the PPDU including the trigger frame.

13. The wireless communication method according to claim 9, Among them, Perform the spatial reuse operation based on the received signal strength of the PPDU including the trigger frame measured by the OBSS terminal and the spatial reuse parameter obtained by the OBSS terminal.

14. The wireless communication method according to claim 13, Among them, The spatial reuse operation includes an operation of adjusting the transmission power of the OBSS terminal based on the spatial reuse parameter, and wherein the transmission power of the OBSS terminal is set to be lower than the value obtained by subtracting the received signal strength from the value of the spatial reuse parameter.

15. The wireless communication method according to claim 14, Among them, The spatial 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 spatial reuse parameter.

16. The wireless communication method according to claim 9, Among them, The OBSS terminal obtains the spatial reuse parameter from at least one of the trigger frame and the trigger-based PPDU.

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