Wireless Communication Method Using BSS Identifier and Wireless Communication Terminal Thereof

Abstract

The present invention relates to a wireless communication method using a BSS identifier and a wireless communication terminal thereof. Disclosed is a wireless communication terminal for wireless communication. The wireless communication terminal includes: a transmitting and receiving unit configured to transmit and receive wireless signals; and a processor configured to process the wireless signals. The processor generates a trigger frame for triggering random access based on uplink transmission of at least one wireless communication terminal, and inserts the trigger frame into a physical layer protocol data unit (PPDU) to transmit the PPDU.

Description

[0001] This application is a divisional application of the patent application with the application number 201880024847.X (PCT / KR2018 / 004397), the international filing date of which is April 16, 2018, and which entered the Chinese Patent Office on October 12, 2019, and the invention title of which is "Wireless communication method using BSS identifier and wireless communication terminal using the same". Technical Field

[0002] The present invention relates to a wireless communication method using a BSS identifier and a wireless communication terminal. Background Art

[0003] In recent years, with the expansion of the supply of mobile devices, wireless communication technologies that can provide fast wireless Internet services to mobile devices have attracted significant public attention. Wireless communication technologies allow mobile devices including smart phones, smart tablets, laptop computers, portable multimedia players, embedded devices, etc. to access the Internet wirelessly in a home or company or a specific service providing area.

[0004] One of the most well-known wireless communication technologies is wireless LAN technology. Since the initial wireless LAN technology was supported using a frequency of 2.4 GHz, 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 a frequency in the 2.4 GHz band. IEEE 802.11a, which was commercialized after IEEE 802.11b, uses a frequency in the 5 GHz band instead of the 2.4 GHz band, reduces the impact of interference compared to the significantly congested frequency in the 2.4 GHz band, and increases the communication speed up to a maximum of 54 Mbps by using orthogonal frequency division multiplexing (OFDM) technology. However, IEEE 802.11a has the disadvantage that the communication distance is shorter than that of IEEE 802.11b. In addition, IEEE 802.11g uses a frequency in the 2.4 GHz band similar to IEEE 802.11b to achieve a maximum communication speed of 54 Mbps and satisfies backward compatibility to attract significant public attention, and furthermore, it is superior to IEEE 802.11a in terms of communication distance.

[0005] In addition, as a technical standard established to overcome the limitations of communication speed pointed out as a weakness in wireless LANs, IEEE 802.11n has been provided. The purpose of IEEE 802.11n is 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) with a data processing speed of up to 540 Mbps or higher, and further, multiple-input multiple-output (MIMO) technology that uses multiple antennas on both the transmitting unit and the receiving unit based on multiple antennas in order to minimize transmission errors and optimize data speed. In addition, the standard can use a coding scheme that sends multiple overlapping copies of each other in order to improve data reliability.

[0006] As the supply of wireless LANs has become active and further, the applications using wireless LANs have become diverse, the need for a new wireless LAN system that supports higher throughput (very high throughput (VHT)) than the data processing speed supported by IEEE 802.11n has attracted public 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 only defined within the 5 GHz frequency band, but the initial 11ac chipset will even support operation in the 2.4 GHz frequency band for backward compatibility with existing 2.4 GHz frequency band products. Theoretically, according to this standard, the wireless LAN speed of multiple stations can reach up to 1 Gbps at maximum and the maximum single-link speed can reach up to 500 Mbps at maximum. This is achieved by expanding the concept of the wireless interface accepted by 802.11n, such as a wider wireless frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to 8), multi-user MIMO, and high-density modulation (up to 256QAM). In addition, as a scheme for transmitting data by using the 60 GHz frequency band instead of the existing 2.4 GHz / 5 GHz, 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 the transmission of high-bitrate moving images such as massive data or uncompressed HD video. However, because the 60 GHz frequency band is difficult to pass through obstacles, the disadvantage is that the 60 GHz frequency band can only be used between devices within a short-distance space.

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

[0008] In particular, as the number of devices using wireless communication technologies increases, it is necessary to efficiently use the predetermined channels. Therefore, what is needed is a technology that can efficiently use the bandwidth by simultaneously transmitting data between multiple terminals and an AP. SUMMARY OF THE INVENTION

[0009] TECHNICAL PROBLEM

[0010] An object of an embodiment of the present invention is to provide a wireless communication terminal using a BSS identifier.

[0011] TECHNICAL SOLUTION

[0012] According to an embodiment of the present invention, a base station wireless communication terminal for wireless communication includes a transceiver configured to transmit and receive wireless signals, and a processor configured to process wireless signals. The processor may be configured to: generate a trigger frame for triggering a random access based on uplink transmission of at least one wireless communication terminal, and insert the trigger frame into a physical layer protocol data unit (PPDU) to transmit the PPDU.

[0013] When the trigger frame triggers a random access based on uplink transmission of a wireless communication terminal not associated with a basic service set (BSS) operated by the base station wireless communication terminal, the processor may be configured to transmit the PPDU using a PPDU format including a field indicating a BSS color. In this case, the BSS color may be an identifier for identifying the BSS.

[0014] More specifically, when the trigger frame triggers a random access based on uplink transmission of a wireless communication terminal not associated with the BSS operated by the base station wireless communication terminal, the processor may use a high efficiency (HE) PPDU format to transmit the PPDU.

[0015] In another specific embodiment, when the trigger frame triggers a random access based on uplink transmission of a wireless communication terminal not associated with the BSS operated by the base station wireless communication terminal, the processor may be configured to insert a field indicating a BSS color into the trigger frame. In this case, the BSS color may be an identifier for identifying the BSS.

[0016] Specifically, the processor may be configured to insert a field representing the BSS color into a user information field for signaling information that is separately applied to one or more wireless communication terminals triggered by the trigger frame for transmission. In another specific embodiment, a field indicating a BSS color may be inserted into a common information field for signaling information that is commonly applied to one or more wireless communication terminals triggered by the trigger frame for transmission.

[0017] The processor can be configured to set a specific field of a trigger frame to a value of a predetermined Association ID (AID) to trigger random access of a wireless communication terminal not associated with a Basic Service Set (BSS) operated by a base station wireless communication terminal.

[0018] The processor can be configured to send a trigger frame based on a predetermined schedule. In this case, the trigger frame triggers random access based on uplink transmission of a wireless communication terminal that performs a power saving operation based on the predetermined schedule.

[0019] More specifically, the processor can be configured to set a Receiver Address (RA) field of the trigger frame to a group address indicating wireless communication terminals that perform a power saving operation based on a predetermined schedule.

[0020] In another specific embodiment, the trigger frame can include a user information field for signaling information that is individually applied to one or more wireless communication terminals for trigger transmission, and the processor can be configured to set a value of an Association ID (AID) indicated by the user information field corresponding to a band allocated for random access based on uplink transmission to a predetermined value indicating wireless communication terminals that perform a power saving operation based on a predetermined schedule. In this case, the predetermined value can be a reserved value not allocated for another purpose.

[0021] In another specific embodiment, the trigger frame can include a user information field for signaling information that is individually applied to one or more wireless communication terminals for trigger transmission, and the processor can set a TID aggregation limit field included in the user information field corresponding to a band allocated for random access based on uplink transmission to a predetermined value indicating wireless communication terminals that perform a power saving operation based on a predetermined schedule. In this case, the TID aggregation limit field can be a field for indicating a limit on the number of TIDs corresponding to data that can be aggregated in an A-MPDU transmitted based on the trigger frame.

[0022] According to an embodiment of the present invention, a wireless communication terminal that wirelessly communicates with a base station wireless communication terminal includes a transceiver configured to transmit and receive wireless signals; and a processor configured to process the wireless signals. The processor can be configured to: receive a Physical Layer Protocol Data Unit (PPDU) including a trigger frame for triggering transmission to the base station wireless communication terminal, and transmit a trigger-based PPDU based on the trigger frame.

[0023] When a PPDU including a trigger frame indicates a Basic Service Set (BSS) color, the processor may be configured to set the value of the BSS color indicated by the trigger-based PPDU based on the value of the BSS color indicated by the PPDU including the trigger frame. In this case, the BSS color may be one of the identifiers in the identifier that identifies the BSS.

[0024] In addition, if the PPDU including the trigger frame does not indicate a BSS color, the processor may be configured to set the value of the BSS color indicated by the trigger-based PPDU according to the effective BSS color of the wireless communication terminal. In this case, the effective BSS color may indicate the BSS color actually used by the wireless communication terminal.

[0025] The processor may be configured to receive information about a BSS color change from a base station wireless communication terminal. In this case, when reaching the BSS color change time point indicated by the information about the BSS color change, the processor may be configured to set the effective BSS color to the value of the BSS color indicated by the information about the BSS color change.

[0026] The BSS color change time point may be set based on the target beacon transmission time sent by the base station wireless communication terminal.

[0027] If the PPDU uses a partial Association ID (AID) field to indicate a partial BSS color, when the value of the partial AID field is non-zero, the processor may determine whether the PPDU is a PPDU within the BSS or a PPDU between BSSs based on the partial BSS color. In this case, the partial AID field may be a signaling field for indicating a part of the AID value. Additionally, a PPDU within the BSS may be a PPDU sent from the BSS including the wireless communication terminal, and a PPDU between BSSs may be a PPDU sent from a BSS that does not include the wireless communication terminal.

[0028] According to an embodiment of the present invention, an operating method of a base station wireless communication terminal for wireless communication includes generating a trigger frame for triggering a random access based on uplink transmission of at least one wireless communication terminal; and inserting the trigger frame into a Physical Layer Protocol Data Unit (PPDU) to send the PPDU.

[0029] Sending the PPDU may include: when the trigger frame triggers a random access based on uplink transmission of a wireless communication terminal not associated with the Basic Service Set (BSS) operated by the base station wireless communication terminal, sending the PPDU using a PPDU format including a field of the BSS color of the Basic Service Set (BSS) operated by the base station wireless communication terminal.

[0030] Functions of the present invention

[0031] An embodiment of the present invention provides a wireless communication method using a BSS identifier and a wireless communication terminal using the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Shows a wireless LAN system according to an embodiment of the present invention.

[0033] Figure 2 Shows a wireless LAN system according to another embodiment of the present invention.

[0034] Figure 3 Shows a block diagram illustrating the configuration of a station according to an embodiment of the inventive concept.

[0035] Figure 4 Shows a block diagram illustrating the configuration of an access point according to an embodiment of the present invention.

[0036] Figure 5 Shows the process of a station setting an access point and a link according to an embodiment of the present invention.

[0037] Figure 6 Illustrates the operation of multiple wireless communication terminals transmitting trigger-based PPDUs based on a trigger frame according to an embodiment of the present invention.

[0038] Figure 7 Shows a trigger frame format according to an embodiment of the present invention.

[0039] Figure 8 Shows the formats of a common information field and a user information field included in a trigger frame according to an embodiment of the present invention.

[0040] Figure 9 Shows a method for a wireless communication terminal to perform random access according to an embodiment of the present invention.

[0041] Figure 10 Shows a specific format of a UORA parameter set element according to an embodiment of the present invention.

[0042] Figure 11 Shows a method for determining whether a PPDU received by a wireless communication terminal is a BSS-in PPDU or a BSS-out PPDU according to an embodiment of the present invention.

[0043] Figure 12 Shows the power saving operation of a wireless communication terminal according to an embodiment of the present invention.

[0044] Figure 13 Shows the operation of a wireless communication terminal performing UL MU transmission according to an embodiment of the present invention.

[0045] Figure 14Discloses a method for configuring the BSS color of a corresponding PPDU when a base station wireless communication terminal according to an embodiment of the present invention transmits a PPDU including a trigger frame, where the trigger frame triggers the transmission of wireless communication terminals not associated with the base station wireless communication terminal and wireless communication terminals associated with the base station wireless communication terminal.

[0046] Figure 15 Discloses a method for configuring the BSS color of a corresponding PPDU when a base station wireless communication terminal according to an embodiment of the present invention transmits a PPDU to a wireless communication terminal included in a plurality of BSSID sets of a BSS operated by the base station wireless communication terminal.

[0047] Figure 16 Discloses the format of the user information field of a trigger frame according to an embodiment of the present invention.

[0048] Figure 17 Discloses a method in which, when a wireless communication terminal according to an embodiment of the present invention sends a trigger-based PPDU to a base station wireless communication terminal not associated with the wireless communication terminal, the wireless communication terminal sets the value of the BSS color indicated by the trigger-based PPDU.

[0049] Figure 18 Discloses a method for a wireless communication terminal according to an embodiment of the present invention to set the TXVECTOR parameters GROUP_ID and PARTIAL_AID of a VHT SU PPDU.

[0050] Figure 19 Is a view for determining whether a VHT PPDU received by a wireless communication terminal according to an embodiment of the present invention is an inter-BSS PPDU or an intra-BSS PPDU using the value of the partial AID field of the signaling field of the VHT PPDU received by the wireless communication terminal.

[0051] Figure 20 Discloses a wireless communication terminal according to an embodiment of the present invention to set the TXOP duration field of a PPDU.

[0052] Figure 21 Discloses a wireless communication terminal according to another embodiment of the present invention to set the TXOP duration field of a PPDU.

[0053] Figure 22 Discloses a wireless communication terminal according to an embodiment of the present invention to perform UL MU transmission.

[0054] Figure 23 Discloses a wireless communication terminal according to another embodiment of the present invention to perform UL MU transmission.

[0055] Figure 24Shows the coding values of the RU allocation field used by a wireless communication terminal according to an embodiment of the present invention.

[0056] Figure 25 Shows the UL MU transmission for a base station wireless communication terminal not associated with a wireless communication terminal according to an embodiment of the present invention.

[0057] Figure 26 Shows a method for generating an A-MPDU by aggregating MPDUs by a base station wireless communication terminal according to an embodiment of the present invention.

[0058] Figure 27 Shows a method for generating an A-MPDU by a wireless communication terminal according to another embodiment of the present invention.

[0059] Figure 28 Shows a control method for EDCA parameters used by a wireless communication terminal during MU UL transmission according to an embodiment of the present invention.

[0060] Figure 29 Shows a method for a wireless communication terminal to send a BSR according to an embodiment of the present invention.

[0061] Figure 30 Shows the Target Wake Time (TWT) operation of a wireless communication terminal according to an embodiment of the present invention.

[0062] Figure 31 Shows a wireless communication terminal setting MU EDCA parameters in TWT operation according to an embodiment of the present invention.

[0063] Figure 32 Shows the operations of a base station wireless communication terminal and a wireless communication terminal according to an embodiment of the present invention. Detailed Description

[0064] Preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. However, the present invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Parts irrelevant to the description are omitted in the drawings to clearly describe the present invention, and like reference numerals refer to like elements throughout.

[0065] In addition, when it is described that a thing includes (or contains or has) some elements, it should be understood that if there is no specific limitation, it may include (or contain or have) only those elements, or it may include (or contain or have) other elements as well as those elements.

[0066] This application claims priority and the benefit of Korean Patent Application Nos. 10-2017-0048762 (April 14, 2017), 10-2017-0146358 (November 4, 2017), and 10-2017-0146356 (November 4, 2017) filed with the Korean Intellectual Property Office, and the embodiments described and the items mentioned in the corresponding applications are included in the detailed description of this application.

[0067] Figure 1 FIG. is a diagram of a wireless communication system according to an embodiment of the present invention. For convenience of description, embodiments of the present invention are described through a wireless LAN system. The wireless LAN system includes one or more basic service sets (BSSs), and a BSS represents a set of devices that have successfully synchronized with each other to communicate with each other. Generally, BSSs can be classified into infrastructure BSSs and independent BSSs (IBSSs), and Figure 1 FIG. illustrates an infrastructure BSS among them.

[0068] As Figure 1 illustrated in, 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 as stations providing distribution services, and a distribution system (DS) connecting the multiple access points PCP / AP-1 and PCP / AP-2.

[0069] A station (STA) is a predetermined device including a media access control (MAC) that follows the procedures of the IEEE 802.11 standard and a physical layer interface for a wireless medium, and in a broad sense includes a non-access point (non-AP) station and an access point (AP). Additionally, in this specification, the term "terminal" may be used to refer to a concept including a wireless LAN communication device such as a non-AP STA or an AP or both terms. A station for wireless communication includes a processor and a transceiver, and according to this embodiment, may further include a user interface unit and a display unit. The processor may generate frames to be transmitted through a wireless network or process frames received through a wireless network, and in addition, perform various processes for controlling the station. Furthermore, the transceiver is functionally connected to the processor and transmits and receives frames through the wireless network for the station.

[0070] An access point (AP) is an entity that provides access to a distribution system (DS) for stations associated with it via a wireless medium. In an infrastructure BSS, communication between non-AP stations is in principle performed via the AP, but when a direct link is configured, direct communication can also be achieved even between non-AP stations. At the same time, in the present invention, the AP is used as a concept including a personal BSS coordination point (PCP) and may include, in a broad sense, concepts including a centralized controller, a base station (BS), a Node B, a base station transceiver system (BTS), and a site controller.

[0071] Multiple infrastructure BSSs can 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).

[0072] Figure 2 FIG. illustrates a stand-alone BSS as a wireless communication system according to another embodiment of the present invention. For convenience of description, another embodiment of the present invention is described by way of a wireless LAN system. In Figure 2 the embodiment of, a repeated description of parts that are the same as or corresponding to the Figure 1 embodiment of will be omitted.

[0073] Since Figure 2 the BSS3 illustrated in is a stand-alone BSS and does not include an AP, all stations STA6 and STA7 are not connected to the AP. The stand-alone BSS is not permitted to access the distribution system and forms a complete network. In the stand-alone BSS, the corresponding stations STA6 and STA7 can be directly connected to each other.

[0074] Figure 3 is a block diagram illustrating the configuration of a station 100 according to an embodiment of the present invention.

[0075] As Figure 3 illustrated in, the station 100 according to an embodiment of the present invention may include a processor 110, a transceiver 120, a user interface unit 140, a display unit 150, and a memory 160.

[0076] First, the transceiver 120 transmits and receives wireless signals such as wireless LAN physical layer frames and can be embedded in the station 100 or set externally. According to this embodiment, the transceiver 120 may include at least one transmit and receive module using different frequency bands. For example, the transceiver 120 may include transmit and receive modules having different frequency bands such as 2.4 GHz, 5 GHz, and 60 GHz. According to an embodiment, the station 100 may include a transmit and receive module using a frequency band of 6 GHz or higher and a transmit and receive module using a frequency band of 6 GHz or lower. The corresponding transmit and receive modules 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 transmit and receive module. The transceiver 120 may operate only one transmit and receive module at a time or operate multiple transmit and receive modules together simultaneously according to the performance and requirements of the station 100. When the station 100 includes multiple transmit and receive modules, each transmit and receive module may be implemented by independent elements or multiple modules may be integrated into one chip.

[0077] Next, the user interface unit 140 includes various types of input / output devices provided in the station 100. That is, 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 a command of the processor 110 by using various output devices.

[0078] Next, the display unit 150 outputs an image on a display screen. The display unit 150 may output various display objects such as the content executed by the processor 110 or a user interface based on a control command of the processor 110 and the like. In addition, the memory 160 stores control programs used in the station 100 and various resultant data. The control program may include an access program required for the station 100 to access an AP or an external station.

[0079] The processor 110 of the present invention may execute various commands or programs and process data in the station 100. Additionally, the processor 110 may control corresponding units of the station 100 and control data transmission / reception between these units. According to an embodiment of the present invention, the processor 110 may execute a program for accessing an AP stored in the memory 160 and receive a communication configuration message sent by the AP. Additionally, the processor 110 may 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 may represent the main control unit of the station 100 and, according to this embodiment, the processor 110 may represent a control unit for separately controlling a certain component (e.g., the transceiver 120, etc.) of the station 100. The processor 110 may be a modulator and / or demodulator that modulates wireless signals sent to the transceiver 120 and demodulates wireless signals received from the transceiver 120. The processor 110 controls various operations related to wireless signal transmission / reception of the station 100 according to an embodiment of the present invention. Detailed embodiments thereof will be described below.

[0080] Figure 3 The station 100 illustrated in the figure is a block diagram according to an embodiment of the present invention, where individual blocks are illustrated as logically distinct elements of the device. Therefore, the elements of the device may be installed in a single chip or multiple chips depending on the design of the device. For example, the processor 110 and the transceiver 120 may be integrated into a single chip or implemented as separate chips. Additionally, in an embodiment of the present invention, some components of the station 100, such as the user interface unit 140 and the display unit 150, may be optionally provided in the station 100.

[0081] Figure 4 is a block diagram illustrating the configuration of an AP 200 according to an embodiment of the present invention.

[0082] As Figure 4 illustrated, the AP 200 according to an embodiment of the present invention may include a processor 210, a transceiver 220, and a memory 260. In Figure 4 Among the components of the AP 200, a repeated description of parts that are the same as or corresponding to the components of Figure 2 the station 100 will be omitted.

[0083] Referring to Figure 4 According to the present invention, the AP 200 includes a transceiver 220 for operating a BSS in at least one frequency band. As Figure 3As described in the embodiments, the transceiver 220 of the AP 200 may also include multiple transmit and receive modules using different frequency bands. That is, the AP 200 according to an embodiment of the present invention may include two or more transmit and receive modules among different frequency bands (e.g., 2.4 GHz, 5 GHz, and 60 GHz) together. Preferably, the AP 200 may include a transmit and receive module using a 6 GHz or higher frequency band and a transmit and receive module using a 6 GHz or lower frequency band. The corresponding transmit and receive modules may perform wireless communication with a station according to the wireless LAN standard of the frequency band supported by the corresponding transmit and receive module. The transceiver 220 may operate only one transmit and receive module at a time or operate multiple transmit and receive modules simultaneously according to the performance and requirements of the AP 200.

[0084] Next, the memory 260 stores control programs used in the AP 200 and various result-obtained data. The control program may include an access program for managing the access of stations. In addition, the processor 210 may control the corresponding units of the AP 200 and control the data transmission / reception between these units. According to an embodiment of the present invention, the processor 210 may execute a program for accessing a station stored in the memory 260 and send a communication configuration message for one or more stations. In this case, the communication configuration message may include information about the access priority conditions of the corresponding station. In addition, the processor 210 performs access configuration according to the access request of the station. The processor 210 may be a modulator and / or demodulator that modulates a wireless signal sent to the transceiver 220 and demodulates a wireless signal received from the transceiver 220. The processor 210 controls various operations such as the transmission / reception of radio signals of the AP 200 according to the first embodiment of the present invention. Its detailed embodiments will be described below.

[0085] Figure 5 is a diagram schematically illustrating the process of a STA setting a link with an AP.

[0086] Reference Figure 5 , the link between the STA 100 and the AP 200 is generally set through 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. The methods for performing scanning include a passive scanning method in which the AP 200 obtains information by using beacon messages sent periodically (S101) 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).

[0087] The STA 100 that has successfully received the wireless access information in the scanning step performs an authentication step by sending an authentication request (S107a) and receiving an authentication response (S107b) from the AP 200. After the authentication step is performed, 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 means wireless combination, but the present invention is not limited thereto, and in a broad sense, it can include wireless combination and wired combination.

[0088] 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 for the STA 100 and can exist physically associated with the AP 200 or exist as a separate server.

[0089] In a specific embodiment, the AP 200 can be a wireless communication terminal that allocates communication media resources and performs scheduling in an independent network (such as an ad hoc network) not connected to an external distribution service. In addition, the AP 200 can be at least one of a base station, an eNB, and a transmission point TP. The TP 200 can also be referred to as a base station communication terminal.

[0090] The base station wireless communication terminal can be a wireless communication terminal that allocates and schedules media resources for communication with multiple wireless communication terminals. Specifically, the base station wireless communication terminal can be used as a cell coordinator. In a specific embodiment, the base station wireless communication terminal can be a wireless communication terminal that allocates and schedules communication media resources in an independent network (such as an ad-hoc network) not connected to an external distribution service.

[0091] When using orthogonal frequency division modulation (OFDMA) or multiple input multiple output (MIMO) to send data, any one of the wireless communication terminals can simultaneously send data to multiple wireless communication terminals. Moreover, any one of the wireless communication terminals can simultaneously receive data from multiple wireless communication terminals.

[0092] For ease of description, any one of the wireless communication terminals that communicate with multiple wireless communication terminals simultaneously is referred to as a base station wireless communication terminal. In addition, the base station wireless communication terminal may be referred to as a base station communication device. Additionally, the base station wireless communication terminal may be a wireless communication terminal that allocates communication medium resources and communicates with multiple wireless communication terminals to perform scheduling. Specifically, the base station wireless communication terminal may perform the role of a cell coordinator. In this case, the base station wireless communication terminal may be an access point 200. In addition, the multiple wireless communication terminals may be stations 100 associated with the access point 200. In a specific embodiment, the base station wireless communication terminal may be a wireless communication terminal that allocates communication medium resources and performs scheduling in an independent network (such as an ad-hoc network) that is not connected to an external distribution service. Additionally, the base station wireless communication terminal may be at least one of a base station, an eNB, and a transmission point TP. Through Figures 6 to 32 , the operation in which multiple wireless communication terminals send data and the base station wireless communication terminal receives data will be described.

[0093] Figure 6 FIG. illustrates the operation of multiple wireless communication terminals sending trigger-based PPDUs based on a trigger frame according to an embodiment of the present invention.

[0094] The base station wireless communication terminal may send a trigger frame including trigger information for triggering the transmission of at least one wireless communication terminal or the uplink multi-user response scheduling (UMRS) of the MAC header. At least one wireless communication terminal that receives the trigger frame or UMRS including the trigger information may send a trigger-based PPDU based on the trigger information. The trigger-based PPDU may indicate a PPDU including a response frame to the trigger frame. More specifically, the trigger-based PPDU may indicate a HE trigger-based PPDU. One or more wireless communication terminals may use at least one of MU-MIMO and OFDMA to simultaneously send a trigger-based PPDU to the base station wireless communication terminal. In this case, one or more wireless communication terminals may send a trigger-based PPDU within a predetermined time from the reception of the trigger frame or UMRS including the trigger information. At this time, the predetermined time may be the SIFS. Additionally, a frame that sends a response frame to a frame received by a wireless communication terminal within a predetermined time may be referred to as an immediate response.

[0095] As described above, the UMRS may include trigger information. Moreover, the UMRS may be included in the A-control field of the MAC header. Additionally, one or more wireless communication terminals may send a non-HT PPDU in response to the trigger frame. Specifically, when the trigger frame is of the MU-RTS type, one or more wireless communication terminals may send a non-HT PPDU in response to the trigger frame.

[0096] In addition, an A-MPDU may include trigger information. More specifically, an A-MPDU may include a trigger frame. An A-MPDU may include two or more trigger frames. In this case, the content of the trigger frames may be the same. Additionally, when an A-MPDU trigger frame is included, it may not be allowed for a base station wireless communication terminal to include in the A-MPDU an MPDU of a UMRS including an uplink transmission of a wireless communication terminal that is the same as the wireless communication terminal whose uplink transmission is triggered by the trigger frame among the trigger frames.

[0097] In Figure 6 the embodiment of, the AP sends trigger frames to the first station STA1 to the fourth station STA4. The first station STA1 to the fourth station STA4 receive the trigger frames and simultaneously send trigger-based PPDUs to the AP based on the trigger frames. The AP receives the trigger-based PPDUs and sends an ACK frame based on the MPDUs included in the trigger-based PPDUs. The specific format of the trigger frame will be described with reference to Figure 7 Describe the specific format of the trigger frame.

[0098] Figure 7 Illustrates the trigger frame format according to an embodiment of the present invention. Figure 8 Illustrates the formats of the common information field and the user information field included in the trigger frame according to an embodiment of the present invention.

[0099] The trigger frame may include information about the wireless communication terminal for which the trigger frame triggers transmission. Specifically, the trigger frame may include a common information field indicating information that is commonly applied to at least one wireless communication terminal for which the trigger frame triggers uplink transmission. Additionally, the trigger frame may include a user information field indicating information that is individually applied to at least one wireless communication terminal for which the trigger frame triggers uplink transmission. In a specific embodiment, the trigger frame may include a frame control field, a duration field, an RA field, a TA field, a common information field, at least one user information field, a padding field, and an FCS field, as in Figure 7 the embodiment of.

[0100] The RA field may indicate the address of the station that receives the trigger frame. When there is only one wireless communication terminal triggered by the trigger frame, the RA field may indicate the address of the corresponding wireless communication terminal. When there is more than one wireless communication terminal triggered by the trigger frame, the RA field may indicate the broadcast address. When the trigger type of the trigger frame is GCR MU-BAR, the RA field may indicate the address of the group of wireless communication terminals that request the transmission reception status.

[0101] The TA field may indicate the address of the station that sent the trigger frame. When the base station wireless communication terminal does not use multiple BSSIDs, the TA field may indicate the MAC address of the base station wireless communication terminal that sent the trigger frame. Additionally, when the base station wireless communication terminal uses multiple BSSIDs and the base station wireless communication terminal sends a trigger frame to a wireless communication terminal to communicate with the base station wireless communication terminal, the TA field may indicate the MAC address of the base station wireless communication terminal. In this case, the wireless communication terminal that communicates with the base station wireless communication terminal may include not only the wireless communication terminal associated with the base station wireless communication terminal but also the wireless communication terminal not associated with the base station wireless communication terminal. Additionally, when the base station wireless communication terminal uses multiple BSSIDs and the base station wireless communication terminal sends a trigger frame to multiple wireless communication terminals that communicate with two or more BSSs in a set of multiple BSSIDs, the TA field may indicate the BSSID that was sent.

[0102] The padding field may indicate meaningless data. More specifically, when the wireless communication terminal that receives the trigger frame needs time to ensure the readiness for response transmission for the trigger frame, the base station wireless communication terminal may insert the padding field into the trigger frame. In this case, the base station wireless communication terminal may determine the length of the padding field based on the ability of the wireless communication terminal to receive the trigger frame. When the wireless communication terminal that receives the trigger frame does not need time for the response transmission preparation for the trigger frame, the base station wireless communication terminal may not insert the padding field into the trigger frame. The base station wireless communication terminal may indicate the start of the padding field by setting the start portion of the padding field to a specific value. In this case, the specific value may be 0xFFF (4095). Additionally, the base station wireless communication terminal may set the remaining portion of the padding field, other than the start portion, to a value different from the specific value.

[0103] More specifically, the user information field may indicate the frequency band assigned to the wireless communication terminal triggered by the trigger frame. The user information field may include a wireless communication terminal identifier for identifying the wireless communication terminal triggered by the trigger frame and information indicating the bandwidth of the frequency band assigned to the wireless communication terminal. In this case, the wireless communication terminal identifier may be an identifier for shortening the association ID (AID). For example, the trigger frame may include an identifier for shortening the AID of the wireless communication terminal triggered by the trigger frame and an index indicating the frequency band assigned to the wireless communication terminal. In this case, the identifier for shortening the AID may be the 12 least significant bits (LSB) of the AID. According to a specific embodiment, the user information field may include an AID12 field indicating the wireless communication terminal identifier for identifying the wireless communication terminal triggered by the trigger frame.

[0104] The base station wireless communication terminal can set the value of the wireless communication terminal identifier in the user information field to a specific value to indicate that the frequency band of the corresponding user information field is allocated for random access. More specifically, the base station wireless communication terminal can set the value of the wireless communication terminal identifier in the user information field to a first specific value to indicate that the frequency band of the corresponding user information field is allocated for random access of the wireless communication terminal associated with the base station wireless communication terminal. Additionally, the base station wireless communication terminal can set the value of the wireless communication terminal identifier in the user information field to a first specific value to indicate that the frequency band of the corresponding user information field is allocated for random access of the wireless communication terminal not associated with the base station wireless communication terminal. In this case, the first specific value can be 0. Additionally, the second specific value can be 2045. The wireless communication terminal not associated with the base station wireless communication terminal can be a wireless communication terminal not associated with any base station wireless communication terminal.

[0105] The user information field can indicate the frequency band allocated to the wireless communication terminal in resource units (RUs). More specifically, the user information field can include an RU allocation field indicating the RUs allocated to the wireless communication terminal corresponding to the user information field.

[0106] As described above, the wireless communication terminal receiving the trigger frame may need time to prepare to send a response to the trigger frame. In this case, the base station wireless communication terminal can insert a padding field into the trigger frame according to the time required for the wireless communication terminal to prepare to send a response to the trigger frame. The minimum time required for the wireless communication terminal to prepare to send a response to the trigger frame can be referred to as MinTrigProcTime. When the base station wireless communication terminal sends a trigger frame for triggering random access, the base station wireless communication terminal cannot determine which wireless communication terminal will perform transmission through random access. Therefore, when the base station wireless communication terminal sends a trigger frame for triggering random access, there is a problem in the method of setting the fields of the trigger frame at the base station wireless communication terminal to ensure that the wireless communication terminal has the necessary time to prepare to send a response to the trigger frame.

[0107] When a trigger frame triggers random access of a wireless communication terminal associated with a base station wireless communication terminal, the base station wireless communication terminal may set a field of the trigger frame based on the MinTrigProcTime of the wireless communication terminal explicitly triggered by the trigger frame. Specifically, when a trigger frame triggers random access of a wireless communication terminal associated with a base station wireless communication terminal, the base station wireless communication terminal may set a field of the trigger frame based on the longest MinTrigProcTime among the MinTrigProcTimes of the wireless communication terminals explicitly triggered by the trigger frame. In this case, the wireless communication terminal explicitly triggered by the trigger frame may indicate the wireless communication terminal indicated by the identifier of the wireless communication terminal through the above user information field. In another specific embodiment, when a trigger frame triggers random access of a wireless communication terminal associated with a base station wireless communication terminal, the base station wireless communication terminal may set a field of the trigger frame based on the longest MinTrigProcTime among the MinTrigProcTimes of the wireless communication terminals associated with the base station wireless communication terminal.

[0108] When a trigger frame triggers random access of a wireless communication terminal not associated with a base station wireless communication terminal, the base station wireless communication terminal may set a field of the trigger frame based on the maximum value among the MinTrigProcTime values that the wireless communication terminal can signal. In this case, the maximum value among the MinTrigProcTime values that the wireless communication terminal can signal may be 16 us.

[0109] In the above embodiments, the base station wireless communication terminal sets at least one of a padding field, A-MPDU padding, A-MPDU subframe, EOF padding, a frame, and a reserved field of the frame, so that the time required to prepare for sending a response to the trigger frame can be ensured.

[0110] In addition, the base station wireless communication terminal may be inserted before a user information field indicating any one of the wireless communication terminals other than the user information field indicating random access. For example, the base station wireless communication terminal may insert a user information field including an AID12 subfield having a value other than 0 and 2045 before a user information field including an AID12 subfield having a value of 0 or 2045.

[0111] The specific formats of the user information field and the common information field may be shown in Figure 8 (a) and 8(b).

[0112] Figure 9 A method for a wireless communication terminal to perform random access according to an embodiment of the present invention is shown.

[0113] As in the reference Figure 8In the described embodiment, the base station wireless communication terminal may use a trigger frame to trigger the random access of the wireless communication terminal. In this case, the wireless communication terminal may use OFDMA to randomly access the frequency band indicated by the trigger frame. More specifically, the wireless communication terminal may access the RU allocated for random access based on any number in the OFDMA contention window (OCW). In this case, the random number is referred to as the OFDMA backoff (OBO) counter. More specifically, the wireless communication terminal that receives the trigger frame for trigger random access may reduce the OBO counter by the number of RUs allocated for random access. The wireless communication terminal associated with the base station wireless communication terminal may reduce the OBO counter by the number of RUs indicated by the trigger frame as being allocated for the random access of the wireless communication terminal associated with the base station wireless communication terminal. Additionally, the wireless communication terminal not associated with the base station wireless communication terminal may reduce the OBO counter by the number of RUs indicated by the trigger frame as being allocated for the random access of the wireless communication terminal not associated with the base station wireless communication terminal.

[0114] When the OBO counter becomes 0, the wireless communication terminal is allowed to access any RU allocated for random access. Specifically, when the OBO counter becomes 0, the wireless communication terminal may randomly select any one of the RUs allocated for random access to access the selected RU. In a particular embodiment, the wireless communication terminal associated with the base station wireless communication terminal may randomly select any one of the RUs indicated by the trigger frame as being allocated for the random access of the wireless communication terminal associated with the base station wireless communication terminal. Additionally, the wireless communication terminal not associated with the base station wireless communication terminal may randomly select any one of the RUs indicated by the trigger frame as being allocated for the random access of the wireless communication terminal not associated with the base station wireless communication terminal. When the selected RU is busy, the wireless communication terminal may stop accessing the RU and keep the OBO counter at 0. When the RU is busy according to at least one of physical carrier sensing and virtual carrier sensing, the wireless communication terminal may determine that the RU is busy. In this case, the wireless communication terminal may perform physical carrier sensing and virtual carrier sensing according to the carrier sensing method in the UL MU procedure.

[0115] When the wireless communication terminal receives a new UL OFDMA random access (UORA) parameter set element from the base station wireless communication terminal or performs random access for the first time, the wireless communication terminal may set the OCW to the minimum value OCWmin of the OCW. In this case, the UORA parameter set element may be an element that signals the parameters used for OFDMA random access. Reference will be made to Figure 10Describe in detail the elements of the UORA parameter set. Additionally, the base station radio communication terminal can be a base station radio communication terminal associated with the radio communication terminal. The base station radio communication terminal can be a base station radio communication terminal that receives an uplink transmission to be performed by the radio communication terminal. Additionally, in the case of an unassociated radio communication terminal, the base station radio communication terminal can be a base station radio communication terminal that transmits the UORA parameter set elements or transmits a trigger frame.

[0116] Additionally, the radio communication terminal can adjust the value of the OCW according to the transmission result using random access. In this case, the value of the OCW can indicate the maximum value of the range indicated by the OCW, and the minimum value of the range indicated by the OCW can be 0. More specifically, the radio communication terminal can randomly select one of the natural numbers from 0 to the OCW value and set it as the OBO counter. When the radio communication terminal cannot perform transmission using random access, the radio communication terminal can set the value of the OCW to (2*OCW + 1). In this case, the radio communication terminal can obtain a new OBO counter using the newly set OCW. When the value of the OCW is the maximum value OCWmax that the OCW value can have, the radio communication terminal can keep the value of the OCW as it is. The radio communication terminal can obtain OCWmin and OCWmax from the base station radio communication terminal. More specifically, the radio communication terminal can obtain OCWmin and OCWmax from the UORA parameter set elements received from the base station radio communication terminal. The base station radio communication terminal can use a beacon frame or a probe response frame to transmit the UORA parameter set elements.

[0117] In Figure 9 In the embodiment, the first station STA1 and the second station STA2 are associated with the AP that transmits the trigger frame or the AP included in the same multiple BSSID sets that is the same as the AP that transmits the trigger frame. The OBO counter of the first station STA1 is 5, and the OBO counter of the second station STA2 is 1. The first station STA1 and the second station STA2 receive a trigger frame from the AP indicating that two RUs are allocated for random access. The first station STA1 and the second station STA2 decrement the OBO counter by 2. Since the OBO counter of the second station STA2 reaches 0, the second station STA2 randomly selects one of the two RUs indicated as being allocated for random access by the trigger frame, and then attempts to perform an AP transmission through the selected RU. The second station STA2 receives an ACK for the transmission to the AP. In this case, the second station STA2 sets the OCW to OCWmin, and obtains a new OBO counter value of 6 in the newly set OCW.

[0118] The OBO counter of the first station STA1 is 3, and the OBO counter of the second station STA2 is 6. The first station STA1 and the second station STA2 receive a trigger frame from the AP indicating that three RUs are allocated for random access. The first station STA1 and the second station STA2 decrement the OBO counter by 3. Since the OBO counter of the first station STA1 reaches 0, the first station STA1 randomly selects one of the three RUs indicated as being allocated for random access by the trigger frame, and then attempts to transmit to the AP through the selected RU.

[0119] Figure 10 Shows a specific format of a UORA parameter set element according to an embodiment of the present invention.

[0120] As described above, a base station wireless communication terminal can use a UORA parameter set element to signal parameters for UORA. More specifically, a base station wireless communication terminal can use a beacon frame or a probe response frame to transmit a UORA parameter set element. The UORA parameter set element can include information necessary to obtain OCWmin and OCWmax. More specifically, the UORA parameter set element can include an element ID field, a length field, an element ID extension field, and an OCW range field, as Figure 10 shown. The element ID field and the element ID extension field can indicate values for identifying the UORA parameter set element. Additionally, the length field can indicate the length of the UORA parameter set element. The OCW range field can include information necessary to obtain OCWmin and OCWmax. More specifically, the OCW range field can include an EOCWmin field and an EOCWmax. A wireless communication terminal can obtain 2^EOCWmin - 1 as OCWmin. Additionally, a wireless communication terminal can obtain 2^EOCWmax - 1 as OCWmax.

[0121] A wireless communication terminal can set OCWmin and OCWmax based on the most recently received UORA parameter set element. In this case, a wireless communication terminal can set OCWmin and OCWmax based on the most recently received UORA parameter set element, regardless of the access category (AC) to be transmitted. More specifically, a wireless communication terminal can use the information indicated by the most recently received UORA parameter set element to set OCWmin and OCWmax, regardless of the access category (AC) to be transmitted.

[0122] As in the reference Figures 9 to 10As in the described embodiments, the fact that the wireless access terminal randomly accesses the frequency band indicated by the trigger frame and performs uplink transmission is referred to as random access based on uplink transmission. More specifically, random access based on uplink transmission may indicate that the wireless communication terminal performs uplink transmission using OFDMA in the frequency band indicated by the trigger frame.

[0123] The wireless communication terminal may select the PPDU to be used for transmission according to at least one of the transmission conditions and capabilities of the wireless communication terminal. For example, when the receiver reports that it can receive a DCM or can receive an ER single-user (SU) payload, the wireless communication terminal may send a 242-tone extended range (ER) SU PPDU to the wireless communication terminal to receive the PPDU. Additionally, when the receiver reports that it can receive a UL HE MU PPDU, the wireless communication terminal may send the UL HE MU PPDU to the wireless communication terminal that is to receive the PPDU. Whether to receive an ER single-user (SU) payload may be whether to receive a 106-tone ER SU PPDU. Additionally, when the wireless communication terminal receives a HE ER PPDU using STBC or receives a HE SU PPDU using STBC, the wireless communication terminal may send a PPDU including a control frame in response to the received PPDU using the same format as the received PPDU.

[0124] Furthermore, the base station wireless communication terminal may send a PPDU including a control frame using the PPDU format supported by the receiver in response to a trigger-based PPDU. When the base station wireless communication terminal sends a trigger frame that is not of the MU RTS type, the base station wireless communication terminal may send a PPDU including the trigger frame using the PPDU format supported by the receiver. When the wireless communication terminal receives a PPDU including a trigger frame that is not of the MU RTS type or a MAC frame including UMRS, the wireless communication terminal may send a trigger-based PPDU including a control frame in response to the corresponding PPDU.

[0125] When the wireless communication terminal receives a HE ER SU PPDU including a fine timing measurement (FTM) frame or a HE SU PPDU including an FTM frame, the wireless communication terminal may send an ACK frame using the same format as the received PPDU in response to the FTM frame. In this case, when the wireless communication terminal receives a HE SU PPDU including an FTM frame after being associated with the transmitter and the most recently successfully sent PPDU is a HE ER SU PPDU, the wireless communication terminal may send a control frame to the HE ER SU PPDU.

[0126] When a wireless communication terminal transmits a control frame in response to a HE ER SU PPDU, the wireless communication terminal may use the HE ER SU PPDU to transmit the control frame. When the most recently successful PPDU after the wireless communication terminal is associated with a transmitter is not a HE ER SU PPDU, the wireless communication terminal may use a non-high efficiency (HE) PPDU to transmit the control frame.

[0127] When a wireless communication terminal transmits a control frame in response to a HE ER SU PPDU, the wireless communication terminal may use a non-HT PPDU or a non-HT repeated PPDU to transmit the control frame. When the most recently successful PPDU after the wireless communication terminal is associated with a transmitter is not a HE ER SU PPDU, the wireless communication terminal may use the HE ER SU PPDU to transmit the control frame.

[0128] In a subsequent TXOP, a PPDU format change may occur between a HE ER SU PPDU and a non-HT PPDU. More specifically, the wireless communication terminal may transmit a HE ER SU PPDU in response to a non-HT PPDU. Additionally, the wireless communication terminal may transmit a non-HT PPDU in response to a HE ER PPDU. A transmitter that requests the transmission of a control frame in response may set the duration of the TXOP based on the format of the response PPDU. Additionally, when the wireless communication terminal receives an immediate ACK for the most recently transmitted PPDU, the wireless communication terminal may determine that the most recent transmission of the PPDU was successful.

[0129] When multiple BSSs overlap, the communication efficiency of the wireless communication terminal may be reduced due to interference caused by transmissions in another BSS. In particular, when using a frequency band through a contention process, the wireless communication terminal may not even be able to ensure a transmission opportunity due to interference with other wireless communication terminals. To solve this problem, the wireless communication terminal may perform a spatial reuse (SR) operation. Specifically, the SR operation may include an operation of accessing a channel according to whether the received frame is a MAC frame sent from a BSS including the wireless communication terminal or a MAC frame sent from another BSS. For ease of description, when a frame is used in the following description without any description, it is assumed to refer to a MAC frame.

[0130] In a specific embodiment, the operation of accessing a channel may include a NAV setting and reset operation, a CCA operation, and a deferral operation. For example, the wireless communication terminal may adjust a clear channel assessment (CCA) threshold according to whether the frame received by the wireless communication terminal is a frame sent from a BSS including the wireless communication terminal or a frame sent from an OBSS. Additionally, the wireless communication terminal may adjust the transmission power of the PPDU to be transmitted according to the CCA threshold adjustment during the SR operation.

[0131] For ease of explanation, the BSS including the wireless communication terminal is referred to as within the BSS, and the basic service set overlapping with the within-BSS is referred to as the overlapping basic service set (OBSS). In addition, a BSS different from the within-BSS is referred to as between-BSSs. Also, a frame sent from within the BSS is referred to as a within-BSS frame, and a frame sent from the OBSS is referred to as an OBSS frame or a between-BSSs frame. Also, a PPDU sent from within the BSS is referred to as a within-BSS PPDU, and a PPDU sent from the OBSS is referred to as an OBSS PPDU or a between-BSSs PPDU.

[0132] Specifically, the wireless communication terminal may apply a CCA threshold according to whether the received PPDU is a between-BSSs PPDU or a within-BSS PPDU while transmitting the received PPDU. In a specific embodiment, a CCA threshold according to whether the received PPDU is a between-BSSs PPDU or a within-BSS PPDU may be applied while the payload of the received PPDU is being transmitted. In addition, the wireless communication terminal may receive a first PPDU and a second PPDU while applying a CCA threshold according to whether the first PPDU is a between-BSSs PPDU or a within-BSS PPDU. Specifically, the wireless communication terminal may apply a CCA threshold according to whether the received PPDU is a between-BSSs PPDU or a within-BSS PPDU while transmitting the received PPDU. Specifically, when the wireless communication terminal receives a between-BSSs PPDU and applies a CCA threshold corresponding to the between-BSSs PPDU, it may receive a within-BSS PPDU. In this case, the wireless communication terminal may apply a CCA threshold corresponding to the within-BSS PPDU instead of the CCA threshold corresponding to the between-BSSs PPDU. However, when the wireless communication terminal receives a within-BSS PPDU and applies a CCA threshold corresponding to the within-BSS PPDU, and the wireless communication terminal may receive a between-BSSs PPDU while the transmission of the within-BSS PPDU is not completed. In this case, the wireless communication terminal may maintain the CCA threshold corresponding to the within-BSS PPDU until the transmission of the within-BSS PPDU is completed. Specifically, the wireless communication terminal may not apply the CCA threshold corresponding to the between-BSSs PPDU until the transmission of the within-BSS PPDU is completed. In the above operations, the CCA threshold corresponding to the between-BSSs PPDU may be equal to or greater than the CCA threshold corresponding to the within-BSS PPDU. For ease of description, performing preamble detection (PD) using the CCA threshold corresponding to the between-BSSs PPDU may be referred to as an SR operation based on OBSS PD.

[0133] A method of identifying whether the PPDU received by the wireless communication terminal is a within-BSS PPDU or a between-BSSs PPDU will be described.

[0134] A wireless communication terminal can determine whether a PPDU is an intra-BSS PPDU or an inter-BSS PPDU based on the BSS color indicated by the signaling field of the PPDU. In this case, the BSS color is a kind of BSS identifier. Additionally, the number of values that the BSSID can have can be less than the number of values that the BSSID can have. The base station wireless communication terminal determines the BSS color of the BSS operated by the base station wireless communication terminal. In this case, the base station wireless communication terminal can determine any one of 1 to 63 as the BSS color. The BSS colors of the BSSs included in the same multiple BSSI sets may all be the same. Therefore, the base station wireless communication terminal can set the value of the BSS color such that the BSS colors of the BSSs included in the same multiple BSSI sets are the same. The base station wireless communication terminal can signal the BSS color of the BSS operated by the base station wireless communication terminal using a HE operation element or a BSS color change announcement element. A wireless communication terminal other than the base station wireless communication terminal can set the value of the BSS color received from the base station wireless communication terminal as the value of the BSS color field of the HE operation element. Additionally, when the base station wireless communication terminal changes the value of the BSS color of the BSS operated by the base station wireless communication terminal, the base station wireless communication terminal can signal the value of the BSS color to be changed by sending information about the BSS color change. In this case, the information about the BSS color change can be a BSS color change announcement element.

[0135] A wireless communication terminal may set the value of the BSS color received from a base station wireless communication terminal as the value of the active BSS color. In this case, the active BSS color may indicate the BSS color actually used by the wireless communication terminal. More specifically, the BSS color set by the wireless communication terminal as the value of the BSS color field of the HE-SIG-A field of the PPDU and the value of the BSS color field of the HE operation element may be referred to as the active BSS color. Therefore, the wireless communication terminal may set the value of the active BSS color as the value of the BSS color indicated by the PPDU transmitted by the wireless communication terminal. Specifically, the wireless communication terminal sets the value of the active BSS color as the value of the BSS color field of the HE-SIG-A field of the PPDU transmitted by the wireless communication terminal. For example, the base station wireless communication terminal may use the BSS_COLOR of the TXVECTOR parameter to set the value of the active BSS color and set the value of the active BSS color in the BSS color field of the HE-SIG-A field of the PPDU. When the wireless communication terminal receives information about a BSS color change and reaches the BSS color change time point indicated by the information about the BSS color change, the wireless communication terminal may set the active BSS color as the value of the BSS color indicated by the information about the BSS color change. In this case, the value of the BSS color indicated by the information about the BSS color change may be the value indicated by the new BSS color subfield of the BSS color change announcement element. The BSS color change time point may be determined based on the Target Beacon Transmission Time (TBTT). In addition, when the wireless communication terminal establishes an association with another wireless communication terminal, a Tunnel Direct Link Setup (TDLS) link, a Direct Link Setup (DLS) link, or an IBSS membership, the wireless communication terminal may set the value of the BSS color field of the HE-SIG-A field of the PPDU transmitted to the corresponding wireless communication terminal as the value of the active BSS color. In the following description, the value of the BSS color of the BSS may refer to the active BSS color.

[0136] The base station wireless communication terminal may stop the OBSS PD-based SR operation of the wireless communication terminal that receives the PPDU by setting the value of the BSS color indicated by the PPDU to 0. In a specific embodiment, when at least one of the intended receivers of the PPDU is not associated with the BSS operated by the base station wireless communication terminal, the base station wireless communication terminal may set the BSS color indicated by the corresponding PPDU to 0. In addition, when the intended receiver of the HE SU PPDU or the HE ER SU PPDU is not associated with the BSS operated by the base station wireless communication terminal, the base station wireless communication terminal may set the BSS color indicated by the corresponding PPDU to 0.

[0137] When the wireless communication terminal receives a PPDU with a value of 1 to 63 indicating the BSS color, the wireless communication terminal may perform an SR operation based on the OBSS PD. Additionally, when the wireless communication terminal receives a PPDU with a value of 0 indicating the BSS color, the wireless communication terminal may not perform an SR operation based on the OBSS PD. More specifically, when the wireless communication terminal receives a PPDU with a value of 0 indicating the BSS color, the wireless communication terminal may not determine whether the channel is idle based on the OBSS PD threshold. Additionally, when the wireless communication terminal receives a PPDU with a value of 0 indicating the BSS color, the wireless communication terminal may not discard the corresponding PPDU. Specifically, when the wireless communication terminal receives a HE SU PPDU or a HE ER SU PPDU with a value of 0 indicating the BSS color, the wireless communication terminal may not discard the corresponding PPDU. Through these embodiments, the base station wireless communication terminal may send a PPDU to a wireless communication terminal that is not associated with the BSS operated by the base station communication terminal. Additionally, the wireless communication terminal may receive a PPDU from a base station wireless communication terminal that is not associated with the wireless communication terminal.

[0138] When at least one of the intended receivers in the PPDU is not associated with the BSS operated by the base station wireless communication terminal, it may be the case that the intended receiver of the PPDU sent by the base station wireless communication terminal, the intended receiver of the A-MPDU included in the PPDU, or the intended receiver of the frame is not associated with the BSS operated by the base station wireless communication terminal. Additionally, as described above, the base station wireless communication terminal may use a trigger frame to trigger the random access of a wireless communication terminal that is not associated with the base station wireless communication terminal. In this case, the base station wireless communication terminal may set the value of the BSS color indicated by the PPDU including the trigger frame to 0. In this case, the operation of the wireless communication terminal will be described with reference to Figures 11 to 13 the description of the operation of the wireless communication terminal.

[0139] Figure 11 A method for determining whether a PPDU received by a wireless communication terminal is an intra-BSS PPDU or an inter-BSS PPDU according to an embodiment of the present invention is shown.

[0140] As described above, the wireless communication terminal can determine whether the received PPDU is an intra-BSS PPDU or an inter-BSS PPDU based on the BSS color indicated by the signaling field of the PPDU. More specifically, the wireless communication terminal can determine whether the corresponding PPDU is an intra-BSS PBS or an inter-BSS PPDU based on the value of the BSS color indicated by the PPDU received by the wireless communication terminal. The wireless communication terminal can determine the value of the BSS color indicated by the received PPDU based on the value indicated by the BSS color field of the HE-SIG-A field of the received PPDU. More specifically, the wireless communication terminal can determine the value of the BSS color indicated by the received PPDU based on the BSS_COLOR of the RXVECTOR.

[0141] In addition, the wireless communication terminal can determine whether the frame is an inter-BSS frame or an intra-BSS frame based on the MAC header of the frame. Specifically, when the receiver address RA or the transmitter address TA of the MAC header of the frame received by the wireless communication terminal is the BSSID of the BSS including the wireless communication terminal or is included in a set of multiple BSSIDs including the BSSID of the BSS including the wireless communication terminal, the wireless communication terminal can identify the received frame as an intra-BSS frame.

[0142] In addition, the wireless communication terminal can determine whether the VHT PPDU is an inter-BSS PPDU or an intra-BSS PPDU based on the partial AID field of the VHT PPDU. More specifically, the wireless communication terminal can determine whether the VHT PPDU is an inter-BSS PPDU or an intra-BSS PPDU based on the partial AID field and the group ID field of the VHT PPDU. When the group ID field of the VHT PPDU received by the wireless communication terminal is 0 and the value of the partial AID field matches the value from bit 39 to bit 47 of the BSSID included in the BSSID of the BSS including the wireless communication terminal or in a set of multiple BSSIDs included in the BSSID of the BSS including the wireless communication terminal, the wireless communication terminal can identify the VHT PPDU as an intra-BSS PPDU. Additionally, if the group ID field of the VHT PPDU received by the wireless communication terminal is 0 and the value of the partial AID field does not match the value from the bit with index 39 to the bit with index 47 (BSSID[39:47]) of the BSSID included in the BSSID of the BSS including the wireless communication terminal or in a set of multiple BSSIDs included in the BSSID of the BSS including the wireless communication terminal, the wireless communication terminal can identify the VHT PPDU as an Inter-BSS PPDU.

[0143] When the group ID field of the VHT PPDU received by the wireless communication terminal is 63 and the values of the fifth to eighth bits of the partial AID field match the value of the partial BSS color of the BSS including the wireless communication terminal, the wireless communication terminal may identify the VHT PPDU as an in-BSS PPDU. Additionally, when the group ID field of the VHT PPDU received by the wireless communication terminal is 63 and the values of the bits with index 5 to index 8 of the partial AID field (partial AID[5:8]) do not match the value of the partial BSS color of the BSS including the wireless communication terminal, the wireless communication terminal may identify the corresponding VHT PPDU as an inter-BSS PPDU. The partial BSS color may be the four LSBs of the BSS color of the BSS. When the base station wireless communication terminal allows in-BSS PPDUs or inter-BSS PPDUs based in part on the BSS color, the wireless communication terminal may determine whether the VHT PPDU received by the wireless communication terminal is an inter-BSS PPDU or an in-BSS PPDU based on the partial BSS color. The base station wireless communication terminal may indicate the allowance of in-BSS PPDU or inter-BSS PPDU identification based on the partial BSS color using the partial BSS color field of the HE operation element.

[0144] When the TA field of the frame received by the wireless communication terminal does not exist and the RA field matches the transmission opportunity (TXOP) holder address of the BSS including the wireless communication terminal, the wireless communication terminal may identify the frame as an in-BSS frame. At this time, the frame may be restricted to a control frame. Additionally, the TXOP holder may indicate the wireless communication terminal that obtained the TXOP through a contention process.

[0145] Additionally, when the UL / DL field of the HE-SIG-A field of the PPDU received by the base station wireless communication terminal indicates a downlink transmission, the base station wireless communication terminal may identify the corresponding PPDU as an inter-BSS PPDU. In this case, the value of the UL / DL field may be 0.

[0146] In a particular embodiment, when the frame or PPDU received by the wireless communication terminal meets any of the following conditions, the wireless communication terminal may determine the frame as an in-BSS frame or the PPDU as an in-BSS PPDU.

[0147] - The value of the BSS color indicated by the PPDU including the frame is equal to the value of the BSS color of the BSS including the wireless communication terminal. In this case, the value of the BSS color of the BSS including the wireless communication terminal may be the value of the BSS color signaled by the base station wireless communication terminal associated with the wireless communication terminal.

[0148] - When the individual / group bit of the RA field, TA field, or BSSID field of a frame is set to 0, the value of the corresponding field is equal to the BSSID of the BSS including the wireless communication terminal.

[0149] - When the base station wireless communication terminal associated with the wireless communication terminal is a member of multiple BSSID sets and the individual / group bit of the RA field, TA field, or BSSID field of the frame is set to 0, the value of this field is equal to the BSSID of the BSS including the wireless communication terminal.

[0150] - The PPDU is a VHT PPDU, the group ID field of the VHT PPDU is 0, and the value of the partial AID field is equal to the value from bit index 37 to bit index 47 of the BSSID of the BSS including the wireless communication terminal (BSSID[39:47]).

[0151] - The partial BSS color field of the HE operation element recently sent from the BSS including the wireless communication terminal is 1, the PPDU is a VHT PPDU, the group ID field of the VHT PPDU is 63, and the value from bit index 5 to bit index 8 of the partial AID field of the PPDU (partial AID[5:8]) is equal to the BSS color of the partial BSS of the BSS including the wireless communication terminal.

[0152] - The frame is a control frame without a TA field, and the RA field of the frame is equal to the address of the TXOP holder of the BSS including the wireless communication terminal.

[0153] In addition, when the frame or PPDU received by the wireless communication terminal satisfies any one of the following conditions, the wireless communication terminal can determine the frame as an inter-BSS frame or the PPDU as an inter-BSS PPDU.

[0154] - The value of the BSS color indicated by the PPDU is not 0, and the value of the BSS color indicated by the PPDU is not equal to the value of the BSS color of the BSS including the wireless communication terminal. In this case, the value of the BSS color of the BSS including the wireless communication terminal can be the value of the BSS color signaled by the base station wireless communication terminal associated with the wireless communication terminal.

[0155] - When the individual / group bit of the BSSID field of the frame is set to 0, the value of the corresponding field is not equal to the BSSID of the BSS including the wireless communication terminal. In this case, the PPDU receiving the frame may not indicate the BSS color.

[0156] - When a frame does not include a BSSID field and sets the individual / group bits of the RA and TA fields of the frame to 0, the value of any one of the fields is not equal to the BSSID of the BSS including the wireless communication terminal.

[0157] - When the base station wireless communication terminal associated with the wireless communication terminal is a member of multiple BSSID sets and sets the individual / group bits of the RA field, TA field, and BSSID field of the frame to 0, the value of any one of the fields is not equal to the BSSID of the BSS including the wireless communication terminal.

[0158] - The PPDU is a VHT PPDU, the group ID field of the PPDU is 0, and the value of the partial AID field is not equal to the value from bit index 37 to bit index 47 of the BSSID including the wireless communication terminal (BSSID[39:47]).

[0159] - The partial BSS color field of the HE operation element recently sent from the BSS including the wireless communication terminal is 1, the PPDU is a VHT PPDU, the group ID field of the VHT PPDU is 63, and the value from bit index 5 to bit index 8 of the partial AID field of the PPDU (partial AID[5:8]) is different from the BSS color of the partial BSS of the BSS including the wireless communication terminal.

[0160] - The UL / DL field of the HE-SIG-A field of the PPDU received by the base station wireless communication terminal indicates a downlink transmission.

[0161] In the above embodiments, the wireless communication terminal may make the first determination of sending a frame or PPDU between BSSs or within a BSS based on the MAC address prior to the second determination of sending a frame or PPDU between BSSs or within a BSS based on the BSS color indicated by the PPDU. As described above, the PPDU may indicate the BSS color through the BSS color of the HE-SIG-A field. In addition, the PPDU may indicate the BSS color through the group ID field and the partial AID field. In addition, when a frame or PPDU satisfies the in-BSS frame or PPDU condition and the between-BSS frame or PPDU condition, the wireless communication terminal may determine the corresponding frame or PPDU as a between-BSS frame or PPDU. In addition, when a frame or PPDU satisfies neither the in-BSS frame or PPDU condition nor the between-BSS frame or PPDU condition, the wireless communication terminal may not determine the corresponding frame or PPDU as a between-BSS frame or PPDU or an in-BSS frame or PPDU.

[0162] A wireless communication terminal may maintain a Network Allocation Vector (NAV), which is an indicator that the wireless communication terminal does not initiate a continued transmission on the wireless medium. More specifically, the wireless communication terminal may set the NAV based on the duration information indicated by the Duration / ID field of the MAC header. Additionally, the wireless communication terminal may set the NAV based on the duration information indicated by the TXOP duration field of the HE-SIG-A of the PPDU. In this case, when the TXOP duration field of the HE-SIG-A of the PPDU indicates duration information, the wireless communication terminal may set the NAV based on the TXOP duration field of the HE-SIG-A of the PPDU. For example, when all bits of the TXOP duration field of the HE-SIG-A of the PPDU are set to 1, the wireless communication terminal may not set the NAV based on the TXOP duration field of the HE-SIG-A of the PPDU. In these embodiments, when the value of the TXOP indicated by the duration information obtained by the wireless communication terminal from the Duration / field of the MAC header or the TXOP duration field of the HE-SIG-A of the PPDU is greater than the current NAV, the wireless communication terminal may set the NAV according to the obtained duration information.

[0163] The wireless communication terminal may manage the NAV differently depending on whether a frame or a PPDU including the corresponding frame is transmitted within the BSS. Through this, when there is an OBSS, the wireless communication terminal may improve the efficiency of using the wireless medium. More specifically, the wireless communication terminal may maintain two NAVs, that is, the in-BSS NAV set based on the in-BSS PPDU or frame, and the basic NAV set based on the inter-BSS PPDU or frame. In this case, the wireless communication terminal may set the basic NAV based on a PPDU or frame that cannot be recognized as an inter-BSS PPDU or frame or an in-BSS PPDU or frame. Detailed operations related to the NAV setting of the wireless communication terminal will be described.

[0164] When a frame or a PPDU including the corresponding frame does not request an immediate response, the wireless communication terminal may set the in-BSS NAV based on the Duration / ID field of the MAC header of the corresponding frame or the TXOP duration field of the corresponding PPDU. Additionally, when the wireless communication terminal does not send an immediate response even when a frame or a PPDU including the corresponding frame requests an immediate response, the wireless communication terminal may set the in-BSS NAV based on the Duration / ID field of the MAC header of the corresponding frame or the TXOP duration field of the corresponding PPDU. Additionally, when the wireless communication terminal is a TXOP holder, the NAV may be set only based on frames not requested by the wireless communication terminal.

[0165] In addition, when the wireless communication terminal does not obtain duration information from the Duration / ID field of the frame included in the PPDU, the wireless communication terminal may be allowed to set the NAV based on the HE-SIG-A TXOP duration field of the PPDU. When the wireless communication terminal obtains duration information from the Duration / ID field of the frame included in the PPDU and obtains duration information from the TXOP duration field of the HE-SIG-A of the PPDU, the wireless communication terminal may ignore the duration information obtained from the TXOP duration field of the HE-SIG-A of the corresponding PPDU. In this case, the wireless communication terminal may set the NAV according to the duration information obtained from the Duration / ID field of the corresponding frame.

[0166] In addition, when the wireless communication terminal does not trigger the PPDU received by the wireless communication terminal, the wireless communication terminal may be allowed to set the NAV based on the HE-SIG-A TXOP duration field of the PPDU.

[0167] According to the above embodiments, when the wireless communication terminal transmits a trigger-based PPDU, the wireless communication terminal may set the BSS color indicated by the trigger-based PPDU according to the BSS color of the PPDU including the trigger frame requesting the trigger-based PPDU. More specifically, the wireless communication terminal may set the BSS color field of the HE-SIG-A field of the trigger-based PPDU according to the BSS color of the PPDU including the trigger frame requesting the trigger-based PPDU. When the PPDU including the trigger frame requesting the trigger-based PPDU does not indicate a BSS color, the wireless communication terminal may use the value of the BSS color field of the most recently received HE operation element to set the BSS color field of the HE-SIG-A field of the trigger-based PPDU. In addition, when the PPDU including the trigger frame requesting the trigger-based PPDU arrives at the BSS color change time point without indicating a BSS color, the wireless communication terminal may use the new BSS color field value of the most recently received BSS color change announcement element to set the BSS color field of the HE-SIG-A field of the trigger-based PPDU. In this case, the BSS color change time point may be the time point when a predetermined number of TBTTs have elapsed since the base station wireless communication terminal changed the BSS color change announcement element.

[0168] In addition, as described above, when the expected receiver of the trigger frame is not associated with the base station wireless communication terminal that transmits the trigger frame, the base station wireless communication terminal may set the value of the BSS color indicated by the PPDU including the trigger frame to 0. In this case, since the value of the BSS color indicated by the PPDU is 0, when a wireless communication terminal that receives the PPDU including the trigger frame cannot decode the frame included in the PPDU, the wireless communication terminal cannot determine whether the corresponding PPDU is an intra-BSS PPDU or an inter-BSS PPDU. Therefore, according to the above embodiment, a wireless communication terminal that receives the PPDU including the trigger frame may set the basic NAV based on the TXOP duration field of the corresponding PPDU. In this case, when the PPDU is transmitted using a modulation method not supported by the wireless communication terminal, the wireless communication terminal may not be able to decode the frame included in the corresponding PPDU. More specifically, the PPDU may be transmitted using an MCS, DCM, and coding type not supported by the wireless communication terminal. In addition, after the wireless communication terminal receives the preamble of the PPDU, frame decoding may fail. In addition, when the PPDU is a trigger-based PPDU, since the wireless communication terminal cannot determine the composition of the PPDU and the PSDU, it may not be able to receive the frame included in the PPDU.

[0169] In this case, when a PPDU is transmitted from a base station wireless communication terminal associated with the wireless communication terminal, the wireless communication terminal updates the basic NAV even if the intra-BSS NAV needs to be updated. When setting the basic NAV, the wireless communication terminal may not send an immediate response to the base station wireless communication terminal even if the base station wireless communication terminal associated with the corresponding wireless communication terminal requests an immediate response. When the base station wireless communication terminal associated with the wireless communication terminal requests an immediate response, the corresponding wireless communication terminal may ignore the intra-BSS NAV and send an immediate response. When the base station wireless communication terminal associated with the wireless communication terminal requests an immediate response, the corresponding wireless communication terminal may ignore the intra-BSS NAV and send an immediate response. However, this is because the wireless communication terminal cannot ignore the basic NAV and send an immediate response even if the base station wireless communication terminal associated with the wireless communication terminal requests an immediate response.

[0170] In Figure 11 the embodiment of, the AP operating the first BSS BSS1 transmits a trigger frame that triggers the random access of a station not associated with the AP. In this case, the AP sets the BSS color field of the HE-SIG-A of the PPDU including the trigger frame to 0. The first station STA1 included in the first BSS BSS1 configures the basic NAV based on the PPDU including the trigger frame.

[0171] A wireless communication terminal not included in the first BSS BSS1 sets the BSS color to 0 to transmit a trigger-based PPDU. A second station STA2 included in the first BSS BSS1 sets a basic NAV based on the trigger-based PPDU.

[0172] Thereafter, an AP operating the first BSS BSS1 transmits a trigger frame for triggering transmissions of a first station STA1 and a second station STA2. The first station STA1 and the second station STA2 determine that the channel for transmission is busy due to the basic NAV and do not transmit the trigger-based PPDU.

[0173] Figure 12 An energy-saving operation of a wireless communication terminal according to an embodiment of the present invention is shown.

[0174] While a PPDU is being transmitted between other wireless communication terminals in a BSS including a wireless communication terminal, the wireless communication terminal may determine that it cannot receive or transmit the PPDU. In this case, the wireless communication terminal may enter a sleep state. The sleep state may indicate a state in which the wireless communication terminal turns off a part of its functions to reduce power consumption. Specifically, when the wireless communication terminal receives a PPDU within the BSS for which the wireless communication terminal is not the intended receiver, the wireless communication terminal may maintain the sleep state while transmitting the corresponding PPDU. This is because when the wireless communication terminal receives a PPDU within the BSS and the wireless communication terminal is not the intended receiver of the PPDU, the wireless communication terminal cannot receive or transmit the PPDU while transmitting the corresponding PPDU. In a specific embodiment, a wireless communication terminal that is not a base station wireless communication terminal may determine that the wireless communication terminal is not the intended receiver of an uplink (UL) PPDU. Additionally, when a wireless communication terminal that is not a base station wireless communication terminal receives a downlink (DL) PPDU and the identifier of the receiver indicated by the signaling field of the corresponding PPDU does not indicate the wireless communication terminal, the wireless communication terminal may determine that the wireless communication terminal is not the intended receiver of the PPDU. For example, when the HE-SIG-B field of an HE MU PPDU does not indicate the association ID (AID) of the wireless communication terminal, the wireless communication terminal may determine that it is not the intended receiver of the corresponding PPDU. Such an operation of the wireless communication terminal may be referred to as power saving within the PPDU.

[0175] The power-saving operation within the PPDU is described in more detail. When a wireless communication terminal other than a base station wireless communication terminal receives a PPDU that satisfies any one of the following conditions, the wireless communication terminal other than the base station wireless communication terminal may maintain the sleep state until the transmission of the corresponding PPDU is terminated.

[0176] - The PPDU is a HE MU PPDU. The BSS color field of the HE-SIG-A field of the PPDU is equal to the BSS color of the BSS including the wireless communication terminal. The UL / DL field of the HE-SIG-A field of the PPDU indicates a downlink transmission, and the HE-SIG-B of the PPDU does not include a STA ID field indicating the wireless communication terminal or a broadcast ID indicating a plurality of wireless communication terminals including the wireless communication terminal.

[0177] - The PPDU is a HE MU PPDU, a HE SU PPDU, or a HE ER SU PPDU. The BSS color field of the HE-SIG-A field of the PPDU is equal to the BSS color of the BSS including the wireless communication terminal, and the UL / DL field of the HE-SIG-A field of the PPDU indicates an uplink transmission.

[0178] - The PPDU is a HE MU PPDU, a HE SU PPDU, or a HE ER SU PPDU. The BSS color field of the HE-SIG-A field of the PPDU is equal to the BSS color of the BSS including the wireless communication terminal. The UL / DL field of the HE-SIG-A field of the PPDU indicates an uplink transmission, and the PPDU is sent at a rate not supported by the wireless communication terminal.

[0179] - The PPDU is a trigger-based PPDU, and the BSS color field of the HE-SIG-A field of the PPDU is equal to the BSS color of the BSS including the wireless communication terminal.

[0180] - The PPDU is a VHT PPDU. The value of a part of the AID field of the PPDU is equal to the value from the bit with index 37 to the bit with index 47 of the BSSID of the BSS including the wireless communication terminal (BSSID[39:47]), and the value of the group ID field of the PPDU is 0.

[0181] - The MPDU included in the PPDU includes an RA field, a TA field, or a BSSID field, which indicates any one of the BSSID of the BSS including the wireless communication terminal or the BISSID of a plurality of BSSID sets of the BSSID of the BSS including the wireless communication terminal. The RA field does not indicate the MAC address of the wireless communication terminal.

[0182] The wireless communication terminal may set the value indicated by the UL / DL field of the HE-SIG-A field of the transmitted PPDU to the downlink or the UL_FLAG of the TXVECTOR. Additionally, the wireless communication terminal may set the value indicated by the BSS color field of the HE-SIG-A field of the transmitted PPDU to the BSS_COLOR of the TXVECTOR.

[0183] The wireless communication terminal may determine the value indicated by the UL / DL field of the HE-SIG-A field of the received PPDU based on the UL_FLAG of the RXVECTOR. The wireless communication terminal may determine the value indicated by the BSS color field of the HE-SIG-A field of the received PPDU based on the BSS_COLOR of the RXVECTOR. The wireless communication terminal may determine whether the PPDU is transmitted at a rate not supported by the wireless communication terminal based on whether the PHY-RXEND.indication(UnsupportedRate) primitive is received in the MAC layer.

[0184] In Figure 12 an embodiment, the AP operating the first BSS BSS1 transmits a trigger frame that triggers the random access of a station not associated with the AP. In this case, the AP sets the BSS color field of the HE-SIG-A of the PPDU including the trigger frame to 0. The wireless communication terminal not included in the first BSS BSS1 sets the BSS color to 0 to transmit a trigger-based PPDU. Since the value of the BSS color indicated by the trigger-based PPDU is 0, after decoding the signaling field of the PPDU, the first station STA1 included in the first BSS BSS1 may not perform the in-BSS power saving operation. When the first station STA1 decodes the MAC header of the trigger-based PPDU, the first station STA1 may remain in the sleep state until the transmission of the trigger-based PPDU is terminated. When the PPDU indicates the value of the BSS color as 0 in this way, although the wireless communication terminal is capable of performing the in-BSS power saving operation, the wireless communication terminal may not be able to determine that the received PPDU is within the BSS and thus may not be able to perform the in-BSS power saving operation.

[0185] Figure 13 An operation of performing UL MU transmission by a wireless communication terminal according to an embodiment of the present invention is shown.

[0186] As described above, when transmitting an in-BSS PPDU while transmitting an inter-BSS PPDU, the wireless communication terminal may perform CCA using a PD threshold level having a value equal to or greater than the PD threshold level used. In this case, the PD threshold used by the wireless communication terminal may be referred to as the OBSS PD threshold. By doing so, the wireless communication terminal may increase the possibility of the channel being idle compared to the case of transmitting an in-BSS PPDU while transmitting an inter-BSS PPDU. However, when the value of the BSS color indicated by the PPDU is 0, the wireless communication terminal cannot perform the SR operation based on OBSS PD.

[0187] In Figure 13In an embodiment, an AP operating the first BSS BSS1 transmits a trigger frame, and the trigger frame triggers the random access of a station not associated with the AP. In this case, the AP sets the BSS color field of the HE-SIG-A of the PPDU including the trigger frame to 0. The first station STA1 included in the second BSS BSS2 cannot recognize that the PPDU including the trigger frame is an inter-BSS PDDU until the trigger frame is decoded. Therefore, the first station STA1 can determine whether the channel is idle by using the OBSS PD threshold after decoding the trigger frame. In Figure 13 the embodiment, since the first station STA1 uses an OBSS PD threshold greater than the normal PD threshold after decoding the trigger frame, the first station STA1 determines that a channel previously determined to be busy is idle.

[0188] A wireless communication terminal not included in the first BSS BSS1 sets the BSS color to 0 to transmit a trigger-based PPDU. Since the value of the BSS color indicated by the trigger-based PPDU is 0, the first station STA1 cannot recognize whether the trigger-based PPDU is an inter-BSS PPDU. In addition, since the first station STA1 cannot decode the payload of the trigger-based PPDU, the first station STA1 cannot perform an OBSS PD-based SR operation when transmitting the trigger-based PPDU.

[0189] To solve the problems described with reference to Figures 11 to 13 the operations of the wireless communication terminal to be described below can be considered.

[0190] Figure 14 shows a method of setting the BSS color of a corresponding PPDU when a base station wireless communication terminal transmits a PPDU including a trigger frame according to an embodiment of the present invention, where the trigger frame triggers the transmission of a wireless communication terminal not associated with the base station wireless communication terminal and a wireless communication terminal associated with the base station wireless communication terminal.

[0191] A base station wireless communication terminal may set the value of the BSS color indicated by a PPDU including trigger information to the value of the BSS color of the BSS operated by the base station wireless communication terminal other than 0. Specifically, when the trigger information triggers the transmission of a wireless communication terminal not included in the BSS operated by the base station wireless communication terminal, the base station wireless communication terminal may set the value of the BSS color indicated by the PPDU including the trigger information to the BSS color of the BSS operated by the base station wireless communication terminal. The trigger information for triggering the transmission of a wireless communication terminal not included in the BSS operated by the base station wireless communication terminal may be a trigger frame for triggering the random access of a wireless communication terminal not included in the BSS operated by the base station wireless communication terminal. Additionally, the PPDU including the trigger information may be a PPDU including a trigger frame for triggering the transmission of a wireless communication terminal not included in the BSS operated by the base station wireless communication terminal and a frame sent to a wireless communication terminal included in the BSS operated by the base station wireless communication terminal. The PPDU including the trigger information may be a PPDU including a trigger frame for triggering the transmission of a wireless communication terminal not included in the BSS operated by the base station wireless communication terminal and a frame sent to a wireless communication terminal included in the BSS operated by the base station wireless device. Additionally, the PPDU including the trigger information may be a PPDU including a trigger frame for triggering the transmission of a wireless communication terminal not included in the BSS operated by the base station wireless communication terminal and the transmission of a wireless communication terminal included in the BSS operated by the base station wireless communication terminal.

[0192] In Figure 14 In an embodiment, an AP operating the first BSS BSS1 sends a PPDU including a trigger frame. In this case, the base station wireless communication terminal sets the AID field value in the user information field of the trigger frame to 12 and 2045 to perform the transmission of the first station AID 12 associated with the AP and trigger the random access of a wireless communication terminal not associated with the AP. Accordingly, the AP sets the value of the BSS color indicated by the PPDU to the BSS color value of the first BSS BSS1.

[0193] Through these embodiments, the wireless communication terminal can solve the problem caused by uncertainty as to whether the PPDU received by the wireless communication terminal is an intra-BSS PPDU or an inter-BSS PPDU. Additionally, the wireless communication terminal may apply these embodiments to HE SU PPDU or HE ER SU PPDU.

[0194] Figure 15 Shows a method of setting the BSS color of a corresponding PPDU when a base station wireless communication terminal according to an embodiment of the present invention sends a PPDU to a wireless communication terminal included in a plurality of BSSID sets including the BSS operated by the base station wireless communication terminal.

[0195] As described above, when the base station wireless communication terminal transmits a PPDU including trigger information for triggering the transmission of wireless communication terminals included in a plurality of BSSID sets including the BSS operated by the base station wireless communication terminal, the base station wireless communication terminal may set the value of the BSS color indicated by the PPDU to 0. Additionally, a wireless communication terminal that includes the trigger information and receives a PPDU indicating a BSS color value of 0 may set the BSS color value of the trigger-based PPDU to 0 to send the trigger-based PPDU to the base station wireless communication terminal. In this embodiment, similar to those Figures 11 to 13 described, there may be a problem that the wireless communication terminal cannot recognize whether the PPDU is an inter-BSS PPDU or an intra-BSS PPDU.

[0196] When the intended receiver of the PPDU includes wireless communication terminals included in the BSS operated by the base station wireless communication terminal and wireless communication terminals of a BSS corresponding to a plurality of BSSID sets including the BSSID of the BSS operated by the base station wireless communication terminal, the base station wireless communication terminal may set the value of the BSS color indicated by the PPDU to the BSS color value of the BSS operated by the base station wireless communication terminal. More specifically, when the base station wireless communication terminal transmits a PPDU including trigger information for triggering the transmission of wireless communication terminals included in a plurality of BSSID sets including the BSS operated by the base station wireless communication terminal, the base station wireless communication terminal may set the value of the BSS color indicated by the PPDU to the BSS color value of the BSS operated by the base station wireless communication terminal.

[0197] Additionally, the wireless communication terminal may set the value of the BSS color indicated by the trigger-based PPDU to a value other than 0. In the above embodiment, the wireless communication terminal may set the value of the BSS color indicated by the trigger-based PPDU to the BSS color value indicated by the PPDU including the trigger information. Additionally, when the PPDU received by the wireless communication terminal includes trigger information and the BSS color value indicated by the PPDU is 0, the wireless communication terminal may set the BSS color value of the trigger-based PPDU to the BSS value of the BSS color of the BSS operated by the base station wireless communication terminal that sent the trigger information. The wireless communication terminal may send the trigger-based PPDU as a response to the PPDU including the trigger information. In this case, the wireless communication terminal may obtain the BSS color value of the BSS operated by the base station wireless communication terminal from the HE operation element previously sent by the base station wireless communication terminal. Additionally, the base station wireless communication terminal may obtain the BSS color value of the BSS operated by the base station wireless communication terminal from the trigger frame. A more detailed Figure 16 description will be given with reference to this.

[0198] In Figure 15 the embodiment, the AP operating the first BSS BSS1 transmits a PPDU including a trigger frame. In this case, the trigger frame triggers the random access of stations not included in the first BSS BSS1, and the base station wireless communication terminal sets the value of the BSS color indicated by the PPDU including the trigger frame to 0. The station transmitting the trigger-based PPDU based on the trigger frame sets the value of the BSS color indicated by the trigger-based PPDU to the BSS color of the first BSS BSS1 to transmit the trigger-based PPDU to the AP.

[0199] Before the wireless communication terminal obtains the UORA parameter set element from the base station wireless communication terminal, the wireless communication terminal may attempt random access based on the trigger frame transmitted by the base station wireless communication terminal. Specifically, when the trigger frame triggers the random access of a wireless communication terminal not associated with the base station wireless communication terminal, the unassociated wireless communication terminal may attempt random access to the base station wireless communication terminal before obtaining the UORA parameter set element from the base station wireless communication terminal. In this case, the unassociated wireless communication terminal may use a predetermined default UORA parameter set element to attempt random access. Similarly, the PPDU including the trigger frame may not indicate the value of the BSS color of the BSS in which the PPDU is transmitted, and the wireless communication terminal may not obtain the HE operation element from the base station wireless communication terminal that transmits the trigger frame. More specifically, the PPDU including the trigger frame may be a non-HE PPDU. Additionally, the value of the BSS color indicated by the PPDU including the trigger frame may be 0. Thus, the base station wireless communication terminal may signal the BSS color of the BSS operated by the base station wireless communication terminal through the trigger frame. By this, the wireless communication terminal transmitting the trigger-based PPDU cannot obtain the BSS color of the BSS operated by the base station wireless communication terminal that transmits the trigger frame, thereby preventing the failure to set the value of the BSS color indicated by the trigger-based PPDU. A description will be made with reference to Figure 16 this.

[0200] Figure 16 FIG. shows the format of the user information field of the trigger frame according to an embodiment of the present invention.

[0201] The trigger frame may include a field indicating a value of the BSS color of the BSS operated by the base station wireless communication terminal that transmits the trigger frame. More specifically, the common information field of the trigger frame may include a field indicating a value of the BSS color value of the BSS operated by the base station wireless communication terminal that transmits the trigger frame. For ease of description, the field indicating the value of the BSS color is referred to as the BSS color field. More specifically, the common information field of the trigger frame may selectively include the BSS color field for the BSS that transmits the trigger frame. According to a particular embodiment, when the trigger type of the trigger frame is a predefined type, the common information field may selectively include the BSS color field for the BSS that transmits the trigger frame. In this case, the predefined trigger type may indicate a trigger frame that triggers random access of a wireless communication terminal not associated with the base station wireless communication terminal that transmits the trigger frame.

[0202] In another particular embodiment, the user information field of the trigger frame may include the BSS color field for the BSS that transmits the trigger frame. More specifically, the user information field of the trigger frame may selectively include the BSS color field for the BSS that transmits the trigger frame. For example, when the user information field indicates a wireless communication terminal not associated with the base station wireless communication terminal that transmits the trigger frame, the user information field may include the BSS color field of the BSS that transmits the trigger frame. In this case, the user information field may include the BSS color field for the BSS that transmits the trigger frame instead of the SS assignment field. In this case, the wireless communication terminal may assume that the SS assignment field indicates a predetermined value. For example, the wireless communication terminal may consider that the SS assignment field indicates that both STARTING_SS_NUM and NUM_SS are 1.

[0203] Figure 16 (a) shows a specific format of the user information field when the user information field is associated with the base station wireless communication terminal that transmits the trigger frame. Additionally, Figure 16 (b) shows a specific format of the user information field including the BSS color field when the user information field is not associated with the base station wireless communication terminal that transmits the trigger frame in a particular embodiment. In this case, the BSS color field is the BSS color field for the BSS that transmits the trigger frame.

[0204] In another specific embodiment, when the user information field indicates a wireless communication terminal that is not associated with the base station wireless communication terminal that sends the trigger frame, the user information field may further include the BSS color field of the base station that sends the trigger frame. In this case, the length of the user information field indicating a wireless communication terminal that is not associated with the base station wireless communication terminal that sends the trigger frame is different from the length of the user information field indicating that the wireless communication terminal is associated with the base station wireless communication terminal that sends the trigger frame. However, in the trigger frame, when the user information field indicating that the wireless communication terminal is not associated with the base station wireless communication terminal that sends the trigger frame among the user information fields is located behind another user information field and the wireless communication terminal has a user information field indicating the wireless communication terminal, it may no longer be decoded. Therefore, even if the trigger frame includes user information fields of different lengths, the user information field indicating the wireless communication terminal can be found.

[0205] In addition, the base station wireless communication terminal can obtain the value of the BSS color of the BSS operated by the base station wireless communication terminal from the trigger frame. More specifically, the wireless communication terminal can obtain the value of the BSS color of the BSS operated by the base station wireless communication terminal from the BSS color field included in the trigger frame.

[0206] In another specific embodiment, when the base station wireless communication terminal uses the trigger frame to trigger the transmission of a wireless communication terminal that is not associated with the base station wireless communication terminal, the wireless communication terminal can send a trigger-based PPDU only when it obtains the HE operation element sent by the base station wireless communication terminal. This will be described with reference to Figure 17 this.

[0207] Figure 17 A method is shown in which, when a wireless communication terminal according to an embodiment of the present invention sends a trigger-based PPDU to a base station wireless communication terminal that is not associated with the wireless communication terminal, the wireless communication terminal sets the value of the BSS color indicated by the trigger-based PPDU.

[0208] Specifically, when the wireless communication terminal is not associated with the base station wireless communication terminal that sends the trigger frame, the wireless communication terminal can attempt random access based on uplink transmission to the base station wireless communication terminal based on whether it obtains the HE operation element from the base station wireless communication terminal. Specifically, when the wireless communication terminal is not associated with the base station wireless communication terminal that sends the trigger frame and the wireless communication terminal obtains the HE operation element from the base station wireless communication terminal, the wireless communication terminal can attempt random access based on uplink transmission to the base station wireless communication terminal based on the trigger frame. In this case, the wireless communication terminal can set the value of the signaling field of the trigger-based PPDU to indicate the value of the BSS color field of the HE operation element obtained by the trigger-based PPDU. Additionally, when the wireless communication terminal is not associated with the base station wireless communication terminal that sends the trigger frame and the wireless communication terminal does not obtain the HE operation element from the base station wireless communication terminal, the wireless communication terminal can refrain from performing random access based on uplink transmission to the base station wireless communication terminal based on the trigger frame. However, when the wireless communication terminal is not associated with the base station wireless communication terminal that sends the trigger frame and the wireless communication terminal receives a PPDU including the trigger frame and a signaling field indicating the BSS color, even when the HE operation element is not obtained, the wireless communication terminal can perform random access based on uplink transmission to the base station wireless communication terminal based on the trigger frame.

[0209] In Figure 17 the embodiment of, the AP sends a trigger frame that triggers random access of a station not associated with the AP. In this case, among the stations not associated with the AP, the wireless communication terminal that receives the HE operation element from the AP performs random access based on uplink transmission based on the trigger frame. Additionally, the wireless communication terminal can set the value of the BSS color field of the HE-SIG-A field of the trigger-based PPDU to the value of the BSS color field of the HE operation element obtained from the AP.

[0210] Furthermore, the wireless communication terminal can set the value of the signaling field of the trigger-based PPDU such that the trigger-based PPDU indicates a valid BSS color corresponding to the BSS operated by the base station wireless communication terminal instead of the value of the BSS color field of the HE operation element. Specifically, after the BSS color change time point, the wireless communication terminal can set the value of the signaling field of the trigger-based PPDU such that the trigger-based PPDU indicates the value of the BSS color signaled by the base station wireless communication terminal through the BSS color change information.

[0211] In the above embodiments, the base station wireless communication terminal may correspond to multiple BSSID sets. In this case, the wireless communication terminal may receive a HE operation element from the base station wireless communication terminal to obtain a HE operation element from the base station wireless communication terminal of the reference BSSID, and consider the HE operation element from the base station wireless communication terminal of the reference BSSID in the same manner as the HE operation element obtained from the base station wireless communication terminal.

[0212] In another specific embodiment, when the base station wireless communication terminal uses a trigger frame to trigger the transmission of a wireless communication terminal not associated with the base station wireless communication terminal, the wireless communication terminal may send only a PPDU indicating the value of the BSS color. In this case, the PPDU indicating the value of the BSS color may be a HE PPDU. In this case, the transmission of the wireless communication terminal not associated with the base station wireless communication terminal may indicate random access based on uplink transmission.

[0213] As described above, the value of the BSS color may be indicated by using a part of the AID field of the VHT SU PPDU. Reference will be made Figures 18 to 19 to this for description.

[0214] Figure 18 A method for a wireless communication terminal to set the TXVECTOR parameters GROUP_ID and PARTIAL_AID of a VHT SU PPDU according to an embodiment of the present invention is shown.

[0215] Figure 18 The table of shows the GROUP_IP and PARTIAL_AID setting methods for each condition. In this case, [b:c] represents the value from bit index b to bit index c. Additionally, bit n represents bit index n. Thus, bit 0 represents the individual / group bit, and bit 47 represents the last bit of the partial AID field. Additionally, bit position b may be scaled to 2^0, and bit position c may be scaled to 2^(c - b). The base station wireless communication terminal may not assign an AID value with a PARTIAL_AID value of 0 to the wireless communication terminal.

[0216] The base station wireless communication terminal may use the value of the partial AID field to indicate the value of the BSS color of the BSS operated by the base station wireless communication terminal. More specifically, the base station wireless communication terminal may set the value of the partial AID field by using a part of the bits of the value of the BSS color of the BSS operated by the base station wireless communication terminal. More specifically, the base station wireless communication terminal may set the value of the partial AID field by using the following equation.

[0217] AID[5:8] = bin[(BCB[0:3] - (BSSID[44:47] XOR BSSID[40:43])) mod 2^4, 4]

[0218] BCB[0:3] can represent the values from bit index 0 to bit index 3 (4 LSBs) of the BSS color of the BSS. Additionally, bin[x, 4] can be the value representing the decimal value x as a 4-bit binary vector. As described above, the base station wireless communication terminal can set part of the BSS color field of the HE operation element to 1, and then use some bits of the BSS color value to set the value of part of the AID field. The wireless communication terminal can use the value of part of the AID field to determine whether the PPDU received by the wireless communication terminal is an inter-BSS PPDU or an intra-BSS PPDU according to the above inter-BSS PPDU and intra-BSS PPDU determination methods. Specifically, when the value of the group ID field is 63 and the value of part of the AID field is not 0, the wireless communication terminal can use the value of part of the AID field to determine whether the PPDU received by the wireless communication terminal is an inter-BSS PPDU or an intra-BSS PPDU.

[0219] Figure 19 It is a view for determining whether the VHT PPDU received by the wireless communication terminal is an inter-BSS PPDU or an intra-BSS PPDU using the value of part of the AID field of the signaling field of the VHT PPDU received by the wireless communication terminal.

[0220] In reference Figure 18 In the described embodiment, when the value of the BSS color is 48 (b110000) or 16 (b010000), the 4 LSBs of part of the AID field of the PPDU are set to 0. Additionally, when the base station wireless communication terminal sends a VHT PPDU to a wireless communication terminal not associated with the base station wireless communication terminal, the base station wireless communication terminal sets the group ID field to 63 and sets the 4 LSBs of part of the AID field to 0. A wireless communication terminal included in a BSS where the value of the BSS color is 48 (b110000) or 16 (b010000) and not associated with the base station wireless communication terminal can determine that the PPDU is an intra-BSS PPDU even though the PPDU is an inter-BSS PPDU. In Figure 19In an embodiment, the value of the partial BSS color of the first BSS BSS1 is 0. Therefore, when an AP other than the AP operating the first BSS BSS1 sends a VHT PPDU by setting the value of the group ID field of the VHT PPDU to 63 and setting the 4 LSBs of the partial AID field to 0, a station included in the first BSS BSS1 can determine the VHT PPDU as a BSS-internal PPDU. Therefore, a station included in the first BSS BSS1 can perform CCA by applying a PD threshold other than the OBSS PD threshold to the corresponding VHT PPDU. Additionally, when the value of the BSS color of the BSS operated by the base station wireless communication terminal is 48 (b110000) or 16 (b010000), even when the base station wireless communication terminal sends a VHT PPDU to a wireless communication terminal associated with the radio base station, the base station wireless communication terminal sets the 4 LSBs of the partial AID field of the VHT PPDU to 0. Therefore, a wireless communication terminal capable of performing the SR operation may not be able to perform the OBSS PD-based SR operation based on the partial AID field of the VHT PPDU.

[0221] Therefore, when the value of the group ID field of the VHT PPDU received by the wireless communication terminal is 63 and the value of the partial AID field is not 0, it can be determined whether the 4 LSBs of the partial AID field are equal to the value of the BSS color of the BSS including the wireless communication terminal. If the value of the group ID field of the VHT PPDU received by the wireless communication terminal is 63, the value of the partial AID field is not 0, and the 4 LSBs of the partial AID field are equal to the value of the BSS color of the BSS including the wireless communication terminal, the wireless communication terminal can determine the VHT PPDU as a BSS-internal PPDU. In a specific embodiment, when the partial BSS color field of the most recent HE operation element indicates that the partial BSS color is available, the wireless communication terminal can determine whether the 4 LSBs of the partial AID field are equal to the BSD color value of the BSS including the wireless communication terminal.

[0222] Reference will be made to Figures 20 to 21 Describe a method for setting the value of the TXOP duration field of a PPDU by a wireless communication terminal.

[0223] Figure 20 Illustrate a wireless communication terminal according to an embodiment of the present invention setting the TXOP duration field of a PPDU.

[0224] As described above, the wireless communication terminal may set the NAV based on the duration information indicated by the TXOP duration field of the HE-SIG-A of the PPDU. In this case, when the TXOP duration field of the HE-SIG-A of the PPDU indicates duration information, the wireless communication terminal may set the NAV based on the TXOP duration field of the HE-SIG-A of the PPDU. For example, when all bits of the TXOP duration field of the HE-SIG-A of the PPDU are set to 1, the wireless communication terminal may not set the NAV based on the TXOP duration field of the HE-SIG-A of the PPDU. In a specific embodiment, when the wireless communication terminal transmits a PPDU including a PS poll frame, the wireless communication terminal may set the value of the TOXP duration field such that the TOXP duration field does not indicate duration information. Additionally, when the TXOP duration field of the requested response PPDU does not indicate duration information, the wireless communication terminal as the TXOP responder may set the value of the TOXP duration field such that the TOXP duration field does not indicate duration information. Additionally, when the requested response PPDU does not include a TXOP duration field, the wireless communication terminal as the TXOP responder may set the value of the TOXP duration field such that the TOXP duration field does not indicate duration information. In this case, the requested response PPDU may be a non-HE PPDU.

[0225] In addition, the base station wireless communication terminal may signal to the wireless communication terminals included in the BSS operated by the base station communication terminal not to use the BSS color value to determine whether the PPDU received by the wireless communication terminal is an inter-BSS PPDU or an intra-BSS PPDU. To this end, the base station wireless communication terminal may set the value of the BSS color disable field of the HE operation element to 1. For example, since the number of values that the BSS color bit can represent is less than the number of values that the BSS can have, the same BSS color value may be used for different BSSs. At this time, the base station wireless communication terminal may set the value of the BSS disable color field of the HE operation element to 1. If the value of the BSS disable color field of the HE operation element obtained by the wireless communication terminal is 1, the wireless communication terminal may use the MAC header address field instead of the BSS color value indicated by the PPDU to determine whether the PPDU received by the wireless communication terminal is an inter-BSS PPDU or an intra-BSS PPDU. Additionally, when the base station wireless communication terminal sets the value of the BSS color disable field of the HE operation element to 1, the base station wireless communication terminal may set the value of the TOXP duration field such that the TOXP duration field does not indicate duration information.

[0226] However, when the TXOP duration field of a trigger-based PPDU does not indicate duration information, a wireless communication terminal that is not the intended receiver of the trigger-based PPDU may not obtain duration information from the trigger-based PPDU or the frames included in the trigger-based PPDU. This is because a wireless communication terminal that is not the intended receiver of the trigger-based PPDU cannot decode the trigger-based PPDU frame.

[0227] In Figure 20 the embodiment of, the AP operating the first BSS BSS1 sets the TXOP duration field of the PPDU including the trigger frame not to indicate duration information. At this time, when the second station supports PPDU reception, the second station can obtain duration information from the frames included in the PPDU. Since the TXOP duration field of the PPDU does not indicate duration information, the second station sets the TXOP duration field of the trigger-based PPDU transmitted in response to the PPDU including the trigger frame not to indicate duration information. The first station STA1 receives the trigger-based PPDU but cannot obtain duration information from the trigger-based PPDU or the frames included in the trigger-based PPDU. Therefore, the first station STA1 does not set the NAV, and the frame exchange sequence between the AP and the second wireless communication terminal may not be sufficiently protected. Therefore, a method for solving these problems is needed. This will be described with reference to Figure 21 this.

[0228] Figure 21 FIG. shows a wireless communication terminal setting the TXOP duration field of a PPDU according to another embodiment of the present invention.

[0229] When a wireless communication terminal transmits a trigger-based PPDU, the wireless communication terminal can set the value of the TXOP duration field such that the TXOP duration field always indicates duration information. Specifically, when a wireless communication terminal that is a TXOP responder transmits a trigger-based PPDU, regardless of whether the TXOP duration field of the PPDU requesting the response indicates duration information, the wireless communication terminal can set the value of the TXOP duration field such that the TXOP duration field of the transmitted PPDU always indicates duration information. However, when a wireless communication terminal that is a TXOP responder transmits a HE SU PPDU or a HE ER PPDU, the wireless communication terminal can set the TXOP duration field such that the TXOP duration field of the transmitted PPDU does not indicate duration information.

[0230] In Figure 21In the embodiment, the AP configuration for operating the first BSS BSS1 includes that the TXOP duration field of the PPDU including the trigger frame does not indicate duration information. At this time, when the second station supports PPDU reception, the second station can obtain the duration information from the frame included in the PPDU. Although the TXOP duration field of the PPDU does not indicate duration information, the second station sets the value of the TXOP duration field such that the TXOP duration field of the trigger-based PPDU transmitted in response to the PPDU including the trigger frame indicates duration information. The first station STA1 can receive the trigger-based PPDU, but can configure the NAV by obtaining the duration information from the trigger-based PPDU. Therefore, even when the first station STA1 does not receive the PPDU including the trigger frame, the frame exchange sequence between the AP and the second station can be protected.

[0231] When the base station wireless communication terminal changes the BSS color of the BSS, even the wireless communication terminals included in the same BSS can use different BSS colors. Specifically, before the base station wireless communication terminal changes the BSS color of the BSS, the base station wireless communication terminal can send signaling information about the BSS color change as described above. In this case, the signaling information about the BSS color change can be the HE BSS color change announcement element. However, when the wireless communication terminals included in the corresponding BSS fail to obtain the signaling information about the BSS color change and fail to obtain the HE operation element after the BSS color change, even the wireless communication terminals included in the same BSS can use different BSS colors. In this case, the possible problems will be described with reference to Figure 22 the problems that may occur.

[0232] Figure 22 It shows that the wireless communication terminal according to an embodiment of the present invention performs UL MU transmission.

[0233] A wireless communication terminal that receives a PPDU including trigger information may set the value of the BSS color indicated by the trigger-based PPDU to the value of the BSS color field of the HE operation element that the wireless communication terminal most recently received. Specifically, when the PPDU including trigger information does not include a field indicating the BSS color, the wireless communication terminal that receives the PPDU including trigger information may set the value of the BSS color indicated by the trigger-based PPDU to the value of the BSS color field of the HE operation element that the wireless communication terminal most recently received. Additionally, when the wireless communication terminal that receives the PPDU including trigger information cannot use the value of the BSS color indicated by the PPDU including trigger information, the wireless communication terminal that receives the PPDU including trigger information may set the value of the BSS color indicated by the trigger-based PPDU to the value of the BSS color field of the HE operation element that the wireless communication terminal most recently received. In these embodiments, if the wireless communication terminal does not obtain an HE operation element after changing the BSS color, the wireless communication terminal may transmit a modulation signal of the HE-SIG-A field that is different from the modulation signal of the HE-SIG-A field of another wireless communication terminal that simultaneously transmits the trigger-based PPDU. As a result, the base station wireless communication terminal may not be able to receive the trigger-based PPDU.

[0234] In Figure 22 the embodiment, the AP transmits a beacon frame including an HE BSS color change announcement element. In this case, the value of the new BSS color field of the HE color change announcement element is y, the value of the BSS color field of the HE operation element is x, and the color switch countdown field indicates 3. The first station STA1 and the second station STA2 receive the beacon frame to obtain the HE BSS color change announcement element. Each time the AP transmits a beacon frame including the HE BSS color change announcement element, the AP decreases the value of the color switch countdown field and repeats transmitting the beacon frame including the HE BSS color change announcement element. When the value of the color switch countdown field becomes 0, the AP starts using the value of the new BSS color. Therefore, when the AP transmits a PPDU whose value of the color switch countdown field is 0, the AP sets the value of the BSS color field of the HE operation element to y.

[0235] As the BSS color change time point signaled by the HE BSS color change announcement element elapses, both the first station STA1 and the second station change the value of the active BSS color to y. However, the first station SAT1 receives a beacon frame after the BSS color change, but the second station STA2 cannot receive a beacon frame after the BSS color change. Thereafter, the AP sends a trigger frame using a PPDU instead of a HE PPDU. In this case, since the value of the BSS color field of the HE operation element most recently received by the first station STA1 is y, the first station STA1 sends a trigger-based PPDU indicating the BSS color y. Since the value of the BSS color field of the HE operation element most recently received by the second station SAT2 is x, the second station STA2 sends a trigger-based PPDU indicating the BSS color x. Accordingly, the AP may not be able to receive the trigger-based PPDUs sent by the first station STA1 and the second station STA2.

[0236] Figure 23 FIG. shows a wireless communication terminal performing UL MU transmission according to another embodiment of the present invention.

[0237] When a wireless communication terminal sends a trigger-based PPDU, the wireless communication terminal may configure the trigger-based PPDU to indicate the active BSS color of the wireless communication terminal. More specifically, when a wireless communication terminal sends a trigger-based PPDU, the wireless communication terminal may set the value of the BSS color field of the HE-SIG-A field of the trigger-based PPDU to the active BSS color of the wireless communication terminal. According to a particular embodiment, when a wireless communication terminal receives a PPDU including a trigger frame and not indicating a value of the BSS color, the wireless communication terminal may set the value of the BSS color field of the HE-SIG-A field of the trigger-based PPDU to the active BSS color of the wireless communication terminal. A PPDU including a trigger frame and not indicating a value of the BSS color may indicate a non-HE PPDU. As mentioned above, after receiving the BSS color change announcement element, when the BSS color change time point elapses, the wireless communication terminal may set the value of the new BSS color field of the BSS color change announcement element to the value of the active BSS color.

[0238] In Figure 23 the embodiment of, in addition to the operations in which the first station STA1 and the second station STA2 send trigger-based PPDUs, the operations of the AP, the first station STA1, and the second station STA2 are the same as those in Figure 22Those operations in the embodiments are the same. The second station STA2 does not receive a HE operation element from the AP after the BSS color change. However, both the first station SAT1 and STA2 set the value of the BSS color field of the HE-SIG-A of the trigger-based PPDU according to the valid BSS color. Therefore, both the first station SAT1 and the second station STA2 send trigger-based PPDUs indicating that the value of the BSS color is y, and thus the AP successfully receives trigger-based transmissions from each of the first station SAT1 and the second station SAT2.

[0239] By Figures 24 to 25 , a method for transmitting a trigger-based PPDU from a wireless communication terminal not associated with a base station wireless communication terminal to the base station wireless communication terminal will be described. In particular, a method is shown that signals information of an operation channel operated by the base station wireless communication terminal to a base station wireless communication terminal not associated with the base station wireless communication terminal.

[0240] Figure 24 Shows the coding values of the RU allocation field used by a wireless communication terminal according to an embodiment of the present invention.

[0241] When the trigger frame indicates an RU, the trigger frame may indicate the relative position and size of the RU in the operation channel of the BSS in which the frame is transmitted. In this case, the relative position and size of the RU may be a combination of predetermined relative positions and sizes. For example, the trigger frame may indicate which RU in a particular-sized RU to which it corresponds.

[0242] More specifically, the trigger frame may use a reference Figure 8The described RU allocation field indicates the relative position and size of the RU. The bit corresponding to bit index 12 of the RU allocation field may indicate whether the RU is in the primary 80 MHz channel. The bit corresponding to bit index 12 of the RU allocation field may indicate whether the RU is in the primary 80 MHz channel. Additionally, when the RU is in the secondary 80 MHz channel, the value of the bit corresponding to bit index 12 of the RU allocation field may be 1. When the RU has a size of 160 MHz (2 * 996-tone RU), the value of the bit corresponding to bit index 12 of the RU allocation field may be a predetermined value. In another specific embodiment, when the RU has a size of 160 MHz (2 * 996-tone RU), the value of the bit corresponding to bit index 12 of the RU allocation field may be set to any value. Additionally, the values corresponding to bit index 19 to bit index 13 of the RU allocation field may indicate the index of the RU and the size of the RU. When the values corresponding to bit index 19 to bit index 13 of the RU allocation field are from 0 to 36, the values corresponding to bit index 19 to bit index 13 of the RU allocation field may indicate the number of cases where a 26-tone RU can be located in a band with an 80 MHz bandwidth. Additionally, when the values corresponding to bit index 19 to bit index 13 of the RU allocation field are from 37 to 52, the values corresponding to bit index 19 to bit index 13 of the RU allocation field may indicate the number of cases where a 52-tone RU can be located in a band with an 80 MHz bandwidth. More specifically, the values corresponding to bit index 19 to bit index 13 of the RU allocation field and the position of the RU may be mapped as Figure 24 shown.

[0243] Figure 25 FIG. shows UL MU transmission for a base station wireless communication terminal not associated with a wireless communication terminal according to an embodiment of the present invention.

[0244] As described above, a wireless communication terminal not associated with a base station wireless communication terminal may perform transmission to the base station wireless communication terminal based on random access without obtaining an HE operation element or a VHT operation element. More specifically, a wireless communication terminal not associated with a base station wireless communication terminal may perform transmission to the UORA-based base station wireless communication terminal using a default UORA parameter set without obtaining an HE operation element. However, in addition to information about the UORA parameter set, the HE operation element may also indicate information about the operating channel of the BSS operated by the base station wireless communication terminal. More specifically, the HE operation element may signal information about the primary 20 MHz channel used by the base station wireless communication terminal. Additionally, the HE operation element may signal information about the center frequency of the 80 MHz segment. Additionally, as referenced Figure 24As described, the trigger frame may indicate the relative position of the RUs to be used by the wireless communication terminal triggered by the trigger frame. Thus, when a wireless communication terminal not associated with the base station wireless communication terminal does not obtain the HE operation element, the trigger frame may not be able to accurately determine the position of the RU indicating random access.

[0245] As in Figure 25 the embodiment of, the AP may use a frequency band with a bandwidth greater than 20 MHz to transmit a PPDU including a trigger frame. In this case, a station not associated with the AP receives the trigger frame on a channel other than the 20 MHz primary channel used by the base station wireless communication terminal. In this case, the trigger frame may be transmitted as a non-HT repeated PPDU. Additionally, the trigger frame may be transmitted via an HE PPDU in which the legacy preamble and HE-SIG-A fields are repeated every 20 MHz. In this case, a station not associated with the AP may receive the trigger frame but may not be able to determine the position of the 20 MHz primary channel used by the base station wireless communication terminal. Thus, a station not associated with the AP may not be able to accurately determine the position of the RU indicated by the trigger frame for random access. As a result, a station not associated with the AP may attempt a random access to an RU where the trigger frame does not indicate random access. Additionally, even if a station not associated with the AP successfully transmits a trigger-based PPDU, since the station cannot accurately determine the position of the primary 20 MHz channel, the station may not receive an ACK for the trigger-based PPDU.

[0246] Regarding these issues, the base station wireless communication terminal may insert information about the operating channel of the BSS operated by the base station wireless communication terminal into the trigger frame. Specifically, the base station wireless communication terminal may insert information about the primary channel used by the base station wireless communication terminal into the trigger frame. In a particular embodiment, the base station wireless communication terminal may insert information about the 20 MHz primary channel used by the base station wireless communication terminal into the trigger frame. Additionally, the base station wireless communication terminal may insert information about the 80 MHz primary channel used by the base station wireless communication terminal into the trigger frame. The information about the 80 MHz primary channel may be a 1-bit indicator indicating whether the RU in which the trigger frame is transmitted is the primary 80 MHz channel. Additionally, the information about the 80 MHz primary channel may be information indicating the center frequency of the 80 MHz band. Additionally, when the trigger frame triggers a random access of a wireless communication terminal not associated with the base station wireless communication terminal, the base station wireless communication terminal may insert information about the operating channel of the BSS operated by the base station wireless communication terminal into the trigger frame. Additionally, a wireless communication terminal not associated with the base station wireless communication terminal may obtain information about the operating channel of the BSS from the trigger frame and determine the position of the RU indicated by the trigger frame based on the information about the operating channel of the BSS.

[0247] In another specific embodiment, the base station wireless communication terminal may not use the 160 MHz or 80 MHz frequency band to transmit a PPDU including a trigger frame. In another specific embodiment, the base station wireless communication terminal may set the value of the RU allocation field of the trigger frame such that only the RUs whose trigger frames are not in the 160 MHz or 80 MHz frequency band are indicated as the RUs to be used for the transmission triggered by the trigger frame. In another specific embodiment, the base station wireless communication terminal may set the value of the RU allocation field of the trigger frame such that only the RUs not in the secondary 80 MHz frequency band are indicated as the RUs to be used for the transmission triggered by the trigger frame. When the trigger frame triggers the random access of a wireless communication terminal not associated with the base station wireless communication terminal, the base station wireless communication terminal may determine the RUs indicated by the trigger frame according to the constraints of any one of the above embodiments. Additionally, the base station wireless communication terminal may indicate, in the RUs in the 80 MHz segment where the trigger frame is transmitted, the RUs to be used for the random access of a wireless communication terminal not associated with the base station wireless communication terminal.

[0248] Additionally, through the following embodiments, the base station wireless communication terminal can prevent a wireless communication terminal not associated with the base station wireless communication terminal from not receiving a response to a trigger-based PPDU. More specifically, the base station wireless communication terminal may use a non-HT repeated PPDU to transmit a response to a trigger-based PPDU transmitted by a wireless communication terminal not associated with the base station wireless communication terminal. This is because when sending a response to a trigger-based PPDU to a non-HT repeated PPDU, a wireless communication terminal not associated with the base station wireless communication terminal can receive the non-HT repeated PPDU transmitted by the base station wireless communication terminal, regardless of which 20 MHz channel is received. In this case, the base station wireless communication terminal may transmit a response to a trigger-based PPDU transmitted by a wireless communication terminal not associated with the base station wireless communication terminal in the frequency band where the base station wireless communication terminal transmits the trigger frame or in a frequency band including the frequency band where the wireless communication terminal transmits the trigger frame.

[0249] In addition, the base station wireless communication terminal may use a wideband frequency band having a bandwidth greater than 20 MHz to send a response to a trigger-based PPDU transmitted by a wireless communication terminal not associated with the base station wireless communication terminal. In this case, the wideband frequency band having a bandwidth greater than 20 MHz may include a frequency band for trigger-based PPDU transmission by a wireless communication terminal not associated with the base station wireless communication terminal. Additionally, the base station wireless communication terminal may send a response to a trigger-based PPDU transmitted by a wireless communication terminal not associated with the base station wireless communication terminal to an HE SUPPDU or an HE MU PPDU. In such an embodiment, the base station wireless communication terminal may send a response to a trigger-based PPDU transmitted by a wireless communication terminal not associated with the base station wireless communication terminal in the frequency band in which the base station wireless communication terminal transmits a trigger frame or in a frequency band including the frequency band in which the base station wireless communication terminal transmits a trigger frame. When the base station wireless communication terminal sends a response to a trigger-based PPDU in a frequency band having a bandwidth of 160 MHz or 80 + 80 MHz, the base station wireless communication terminal may use a predetermined 80 MHz segment to send a response to the trigger-based PPDU. In this case, the predetermined 80 MHz segment may be an 80 MHz segment including the frequency band in which the base station wireless communication terminal transmits a trigger frame.

[0250] In the above embodiment, the response to the trigger-based PPDU may be an immediate response to the trigger-based PPDU. Additionally, the response to the trigger-based PPDU may be a response sent after the TXOP in which the trigger-based PPDU is transmitted. For example, the trigger-based PPDU may include at least one of a probe request frame, a (re)association request frame, and an authentication request frame. The response to the trigger-based PPDU may include at least one of a probe response frame, a (re)association response frame, and an authentication response frame.

[0251] When a contention process is performed each time an MPDU is sent, as the number of MPDUs to be sent increases, the transmission efficiency may rapidly decrease. To improve the transmission efficiency of the wireless communication terminal, multiple MPDUs may be combined to generate an aggregated MPDU (A-MPDU) and the generated A-MPDU may be sent. A description will be made with reference to Figures 26 to 27 this.

[0252] Figure 26 FIG. shows a method of aggregating MPDUs by a wireless communication terminal to generate an A-MPDU according to an embodiment of the present invention.

[0253] When a wireless communication terminal generates an A-MPDU, the wireless communication terminal can identify individual MPDUs and insert a delimiter for signaling information regarding the MPDUs before each individual MPDU. The delimiter can include an End-of-Frame (EOF) field indicating whether it is the last MPDU of the A-MPDU, a Length field indicating the length of the MPDU, a CRC field for detecting errors in the delimiter, and a delimiter signature field for detecting the delimiter. A delimiter with a value of 0 in the EOF field and a non-zero value in the Length field indicates that the MPDU located after the delimiter is an MPUD that includes data corresponding to the TID agreed upon in the BlockACK transmission. In this way, one or more MPDUs indicated by the delimiter can be referred to as pre-EOF padded A-MPDUs. A delimiter with a value of 1 in the EOF field and a value of 0 in the Length field indicates the end of the A-MPDU after the pre-EOF padded A-MPDU. One or more of these delimiters can be referred to as EOF padded delimiters. Figure 26 (a) shows a specific example of a pre-EOF padded A-MPDU and an EOF padding.

[0254] When a transmitter sends an A-MPDU, the receiver may need to send a BlockAck (BA)-based response frame including a BA bitmap. Therefore, when an A-MPDU includes only one MPDU, the transmission efficiency of the response frame for the A-MPDU is reduced. Additionally, in the 802.11ac standard, a wireless communication terminal should send all MPDUs included in a VHT PPDU to an A-MPDU. To improve this inefficiency, an ACK frame response for an A-MPDU including one MPDU can be allowed. Specifically, when the value of the EOF field of the delimiter is 1 and the value of the Length field is not 0, the delimiter can indicate that the MPDU located after the delimiter is the single MPDU (S-MPDU) in the A-MPDU. The above EOF padding can be located after the S-MPDU. When receiving an A-MPDU indicating an S-MPDU, the wireless communication terminal can send an ACK frame other than a BlockAck as a response to the A-MPDU regardless of whether BA is agreed upon for the TID corresponding to the received MPDU. Figure 26 (b) shows a specific example of an A-MPDU including an S-MPDU.

[0255] Figure 27 Shows a method for generating an A-MPDU by a wireless communication terminal according to another embodiment of the present invention.

[0256] In a particular embodiment, a wireless communication terminal may generate an A-MPDU by combining only MPDUs having the same traffic identifier (TID). In such an embodiment, the wireless communication terminal may not aggregate MPDUs corresponding to multiple TIDs in the A-MPDU, and thus may not transmit the maximum size that can be transmitted using the A-MPDU. As a result, the transmission efficiency through the A-MPDU may be reduced. In another particular embodiment, the wireless communication terminal may aggregate multiple MPDUs having different TIDs to generate one A-MPDU. For ease of explanation, an A-MPDU including multiple MPDUs corresponding to multiple different TIDs is referred to as a multi-TID A-MPDU or an A-MPDU having multiple TIDs. In this embodiment, the number of types of A-MPDUs and the number of response methods for the A-MPDU become larger than those in the foregoing embodiment.

[0257] More specifically, the wireless communication terminal may generate an A-MPDU by aggregating multiple MPDUs having a value of 1 in the EOF field. In this case, each of the multiple MPDUs may correspond to a different TID and may be the only MPDU corresponding to each TID. When an MPDU including quality of service (QoS) data corresponding to a TID having a BA protocol is the only MPDU corresponding to a specific TID within the A-MPDU, the wireless communication terminal may set the value of the EOF field of the delimiter corresponding to the MPDU to 1. Figure 27 (a) shows a specific example of an A-MPDU in which multiple MPDUs having an EOF field value of 1 are aggregated. Additionally, when an action frame requesting a response of an ACK frame is unique in the corresponding A-MPDU, the value of the EOF field of the delimiter corresponding to the action frame may be set to 1. Figure 27 (b) shows a specific example of an A-MPDU in which an MPDU having an EOF field value of 1 and an action frame having an EOF field value of 1 are aggregated. When an MPDU corresponding to a delimiter having an EOF field of 1 is transmitted alone, the receiver may transmit an ACK frame in response to the MPDU. Figure 27 (c) shows a case where the A-MPDU includes only one MPDU corresponding to a delimiter having an EOF field of 1.

[0258] When an MPDU corresponding to a delimiter with an EOF field value of 1 is transmitted together with another MPDU that requires an immediate response, the receiver may transmit each AID TID field, where the BA bitmap is omitted in the multi-BA (M-BA) in response to the MPDU corresponding to a delimiter with an EOF field value of 1. In this case, the receiver may set the value of the Ack type field of each AID TID field, where the BA bitmap is omitted, to be different from the value of the Ack type field of each other AID TID field that includes the BA bitmap. More specifically, the receiver may set the value of the Ack type field of each AID TID field to 1. In addition, each AID TID field where the BA bitmap is omitted is referred to as an Ack context, and each AID TID field that includes the BA bitmap is referred to as a BA context.

[0259] The wireless communication terminal sets the value of the EOF field of the corresponding delimiter to 1, aggregates the MPDU corresponding to the TID without the BA protocol and the MPDU corresponding to another TID, and transmits the MPDU corresponding to the TID without the BA protocol and the MPDU corresponding to another TID. In this case, the receiver may transmit an M-BA including an Ack context response in response to the MPDU corresponding to the TID without the BA protocol. When the wireless communication terminal transmits the MPDU corresponding to the TID without the BA protocol by using an A-MPDU, it can be ensured that the MPDU corresponding to the TID without the BA protocol is the only MPDU corresponding to that TID in the corresponding A-MPDU. Therefore, the wireless communication terminal may set the value of the EOF field of the delimiter corresponding to the MPDU corresponding to the TID without the BA protocol to 0. In this case, when another MPDU of the A-MPDU requires an immediate response, the receiver may transmit an M-BA including an Ack context response in response to the MPDU corresponding to the TID without the BA protocol. Additionally, the wireless communication terminal may set the value of the EOF field of the delimiter corresponding to the MPDU corresponding to the TID with the BA protocol to 0. In such an embodiment, even if the value of the EOF field of the delimiter is 1, the receiver cannot determine solely based on the corresponding delimiter that the MPDU corresponding to the delimiter is the only MPDU in the A-MPDU. In this case, the receiver may determine that the MPDU is the only MPDU in the corresponding A-MPDU based on the data included in the MPDU and other delimiters.

[0260] As described above, in a frequency band (such as an unlicensed band) commonly used by various wireless communication devices, a wireless communication terminal can access a channel through a contention process. Specifically, when the channel to be accessed by the wireless communication terminal is idle within a predetermined time, the wireless communication terminal starts a backoff process. During the backoff process, the wireless communication terminal obtains a random integer value in a contention window (CW) and sets the random integer value as a backoff timer. When the corresponding channel is idle within a predetermined slot time, the wireless communication terminal decrements the backoff timer. When the value of the backoff timer is 0, the wireless communication terminal accesses the corresponding channel. In this case, when the corresponding channel is busy, the wireless communication terminal stops the backoff process. When the channel to be accessed by the wireless communication terminal is idle within a predetermined time, the wireless communication terminal resumes the backoff process again.

[0261] In addition, the wireless communication terminal can access the channel according to the priority of the data to be transmitted. Specifically, the wireless communication terminal can use a CW determined according to the priority of the data to be transmitted. In this case, the minimum CW value CWmin and the maximum CW value CWmax are determined according to the priority of the data to be transmitted by the wireless communication terminal. In addition, a predetermined time for the wireless communication terminal to wait before starting the backoff process is determined according to the priority of the data to be transmitted by the wireless communication terminal. In addition, the wireless communication terminal can wait for a specified time according to the priority of the data to be transmitted and then start the backoff process. The time specified according to the priority is called the arbitration interframe space (AIFS). This operation is called enhanced distributed channel access (EDCA). In addition, the priority of the data can be determined according to the access category (AC).

[0262] As described above, the base station wireless communication terminal can trigger an uplink transmission of the base station wireless communication terminal to one or more wireless communication terminals. In this case, the base station wireless communication terminal accesses the channel for the uplink transmission of one or more wireless communication terminals. In addition, one or more wireless communication terminals access the channel to perform an uplink transmission for each of the one or more wireless communication terminals. Therefore, when the uplink transmission of one or more wireless communication terminals is scheduled for the uplink transmission by the base station wireless communication terminal, the uplink transmission of the one or more wireless communication terminals has a higher priority than other wireless communication terminals transmitting data with the same priority. In addition, since the base station wireless communication terminal and one or more wireless communication terminals access the channel simultaneously for the same transmission, the channel access efficiency may be reduced. Therefore, when scheduling uplink multi-user (UL-MU) transmission, it is necessary to adjust the EDCA parameter values. This will be described with reference to Figures 28 to 31 this.

[0263] Figure 28Disclosed is a method for controlling EDCA parameters used by a wireless communication terminal during MU UL transmission according to an embodiment of the present invention.

[0264] When a wireless communication terminal scheduled for UL MU transmission is successful in UL MU transmission, the wireless communication terminal may use a channel access method that guarantees successful channel access with a lower probability compared to when it is not scheduled for UL MU transmission. More specifically, the wireless communication terminal may use a separate set of EDCA parameters. In a specific embodiment, the corresponding wireless communication terminal may use a set of EDCA parameters that attempts to access the channel with a lower probability in channel access for transmitting the same data than the previously used set of EDCA parameters. In this case, the set of EDCA parameters is a set of parameters used in EDCA operation according to the priority of the data transmitted by the wireless communication terminal. Specifically, the set of EDCA parameters may include parameters for CW. In this case, the parameters for CW may include at least one of CWmin and CWmax. Additionally, the set of EDCA parameters may include a parameter value related to a predetermined time for which the wireless communication terminal waits to start the backoff process. In this case, the predetermined time may be the above-mentioned AIFS. For ease of description, when a wireless communication terminal scheduled for UL MU transmission is successful in UL MU transmission, the separate set of EDCA parameters used by the corresponding wireless communication terminal is referred to as the MU EDCA parameter set.

[0265] Additionally, when a wireless communication terminal scheduled for UL MU transmission is successful in UL MU transmission, it may represent a case where all of the following conditions are satisfied. 1) The wireless communication terminal sends information about the data to be transmitted to the base station wireless communication terminal. In this case, the wireless communication terminal may send information about the data to be transmitted to the base station wireless communication terminal by sending a buffer status report (BSR). 2) The wireless communication terminal receives trigger information that includes a user information field indicating the AID of the wireless communication terminal. In this case, the trigger information may be a trigger frame. 3) The wireless communication terminal sends QoS data in response to the trigger information. 4) The wireless communication terminal determines that the QoS data transmission is successful. In this case, when the wireless communication terminal receives an immediate response to the QoS data transmission, the wireless communication terminal may determine that the QoS data transmission is successful.

[0266] The base station wireless communication terminal may send information about the MU EDCA parameter set to the wireless communication terminal. More specifically, the base station wireless communication terminal may send an MU EDCA parameter set element including information about the MU EDCA parameter set to the wireless communication terminal. In this case, the base station wireless communication terminal may use a beacon frame to send the MU EDCA parameter set element.

[0267] When the wireless communication terminal receives the MU EDCA parameter set element and meets the above conditions, the wireless communication terminal may update the EDCA parameter values of all ACs corresponding to the QoS data transmitted by the wireless communication terminal through trigger-based PPDU. Specifically, the wireless communication terminal may update the end time point of the PPDU including the immediate response to the trigger-based PPDU or the end value of the trigger-based PPDU including the QoS data that does not request an immediate response through the EDCA parameter values of all ACs corresponding to the QoS data.

[0268] When the MU EDCA parameter set application condition is not met until a predetermined time elapses from when the timer is set, the wireless communication terminal may set the MU EDCA timer for terminating the MU EDCA parameter set application. Specifically, when receiving the trigger information, the wireless communication terminal may set the MU EDCA timer. In this case, if the MU EDCA parameter set application condition is not met within a certain time after setting the MU EDCA timer, the wireless communication terminal may terminate the MU EDCA parameter set application. In this case, the MU EDCA timer may be applied to each AC. In addition, the MU EDCA timer value may also be included in the MU EDCA parameter set. Therefore, the base station wireless communication terminal may send the MU EDCA parameter set element including the information about the MU EDCA timer value to the wireless communication terminal.

[0269] In Figure 28 In an embodiment, the AP sends a trigger frame to the first station STA1. The first station STA1 receives the trigger frame from the AP and sends a trigger-based PPDU based on the trigger frame, where the AC includes QoS data corresponding to BE. The AP receives the trigger-based PPDU from the first station STA1 and sends an M-BA in response to the MPDU including the trigger-based PPDU. The first station STA1 receives the M-BA from the base station wireless communication terminal and applies the MU EDCA parameter set to the QoS data where the AC is BE. In this case, the first station STA1 sets the MU EDCA timer for the QoS data where the AC is BE. Before the MU EDCA timer expires, the first station STA1 fails to successfully send the UL MU. Therefore, when the MU EDCA timer expires, the first station STA1 terminates the application of the MU EDCA parameter set.

[0270] Figure 29 A method for a wireless communication terminal to send a BSR according to an embodiment of the present invention is shown.

[0271] As described above, for a base station wireless communication terminal, it is important to determine the buffer state of a wireless communication terminal associated with the base station wireless communication terminal. To this end, the wireless communication terminal can use various methods to send a BSR to the base station wireless communication terminal. More specifically, the wireless communication terminal can use the queue size subfield of the QoS control field of QoS data to send a buffer status report (BSR). In this case, the BSR is information indicating the buffer state.

[0272] The wireless communication terminal can set the 2 most significant bits (MSB) to the SF subfield indicating the scaling factor in the queue size subfield, and set the remaining 6 bits to the UV subfield indicating the unscaled value. The specific format of the queue size subfield can be as Figure 29 shown. In this case, the wireless communication terminal can obtain an approximation of the total amount of MPDUs included in the currently transmitted A-MPDU and the data stored in the buffer of the same TID, according to the formula specified for each scaling factor, and insert the obtained approximation into the queue size subfield. The wireless communication terminal can perform a ceiling operation while obtaining the approximation of the total amount of data. The base station wireless communication terminal can estimate the total amount of buffered data of the wireless communication terminal based on the queue size subfield received from the wireless communication terminal. In this case, since the wireless communication terminal determines the value of the queue size subfield based on the ceiling total amount value of the buffered data, even if the buffer of the wireless communication terminal corresponding to a specific TID is empty, the base station wireless communication may determine that data is buffered by a value within the error range due to the ceiling operation on the buffer of the wireless communication terminal corresponding to a specific TID. Therefore, the base station wireless communication terminal may additionally unnecessarily schedule a UL transmission of the wireless communication terminal. Therefore, the wireless communication terminal can obtain an approximation of the total amount of MPDUs included in the currently transmitted A-MPDU and the data stored in the buffer of the same TID by using a floor operation. More specifically, the base station wireless communication terminal can obtain the value to be inserted into the queue size subfield according to the following rules.

[0273] - When the value of the scaling factor is 0, the wireless communication terminal can round down the actual queue size to the nearest 16 octets and insert it into the UV subfield.

[0274] - When the value of the scaling factor is 1, the wireless communication terminal can round down the value obtained by subtracting 1024 from the actual queue size to the nearest 256 octets and insert it into the UV subfield.

[0275] - When the value of the scaling factor is 2, the wireless communication terminal can round down the value obtained by subtracting 17408 from the actual queue size to the nearest 2048 octets and insert it into the UV subfield.

[0276] - When the value of the scaling factor is 3, the wireless communication terminal may round down the value obtained by subtracting 148,480 from the actual queue size to the nearest 32,768 octets and insert it into the UV subfield.

[0277] In this case, the actual queue size may indicate the total amount of data stored in the buffers of the MPDUs included in the currently transmitted A-MPDU and of the same TID.

[0278] In this embodiment, even if the data sent from the AP to the terminal remains in the buffer of the wireless communication terminal, the base station wireless communication terminal may not schedule the UL transmission of the corresponding wireless communication terminal. However, the wireless communication terminal may send the data stored in the buffer by means of an SU transmission and may send the data stored in the buffer together when scheduling an uplink transmission for another TID. Therefore, compared with the case where the wireless communication terminal inserts the value obtained based on a ceiling operation into the queue size subfield, the case where the wireless communication terminal inserts the value obtained based on a floor operation into the queue size subfield may be more efficient in terms of resource management.

[0279] In another specific embodiment, when the wireless communication terminal sends all the buffered data of the TID indicated by the queue size subfield, the wireless communication terminal may set the value of the queue size subfield to a predetermined value. In this case, the predetermined value may be 11111110.

[0280] Figure 30 Illustrates the Target Wake Time (TWT) operation of a wireless communication terminal according to an embodiment of the present invention.

[0281] In the 802.11ah standard, a wireless communication terminal and a base station wireless communication terminal separately set a TWT and a service period (SP) of the TWT. The base station wireless communication terminal according to an embodiment of the present invention may signal information related to the TWT and the SP of the TWT to all wireless communication terminals of a BSS operated by the base station wireless communication terminal. More specifically, the base station wireless communication terminal may signal information related to the TWT and the corresponding SP of the TWT by using a beacon frame. The base station wireless communication terminal may signal that it will send a trigger frame in the SP of the TWT, and the trigger frame triggers random access based on uplink transmission. In this case, the base station wireless communication terminal sets the trigger field of the request type field in the TWT element to 1, and sets the TWT flow identifier field to a value other than 1, so that it can indicate that a trigger frame for triggering uplink transmission is to be sent in the SP of the TWT. In such an embodiment, a wireless communication terminal supporting random access may perform TWT operation without additional negotiation with the base station wireless communication terminal. More specifically, the wireless communication terminal may remain in a sleep state until the TWT and transition to a wake state during the TWT. In this case, the wireless communication terminal may send a frame indicating that the wireless communication terminal is in a wake state to the base station wireless communication terminal. In this case, the frame indicating the wake state may be a PS poll frame or an Unscheduled Automatic Power Save Delivery (U-APSD) trigger frame.

[0282] In addition, the base station wireless communication terminal may send a trigger frame in the TWT, and the trigger frame is used to trigger the transmission of information about the buffer state of the wireless communication terminal in a wake state. In this case, the information about the buffer state may be a bufferable unit (BU). Additionally, the trigger frame for triggering the transmission of information about the buffer state may trigger uplink transmission of all wireless communication terminals of a BSS operated by the base station wireless communication terminal and the wireless communication terminal performing TWT operation. Therefore, the random access success rate of the wireless communication terminal performing TWT operation may be very low. Therefore, the wireless communication terminal may set the receiver address (RA) field of the trigger frame sent at the TWT to the group address of the wireless communication terminals participating in the TWT operation. More specifically, the base station wireless communication terminal may set the RA field of the trigger frame sent at the TWT as shown in Figure 30 1) of. Additionally, the base station wireless communication terminal may signal the group address of the wireless communication terminals participating in the TWT operation by using the TWT element. In this embodiment, when the wireless communication terminal receives a trigger frame in which the value of the RA field is the group address of the wireless communication terminals participating in the TWT operation, only the wireless communication terminal that is to exchange frames with the wireless communication terminal in the TWT SP may attempt random access based on the trigger frame.

[0283] In another specific embodiment, the base station wireless communication terminal may set the value of the AID12 sub-field in the user information field of the trigger frame transmitted at the TWT to a predetermined value indicating that the wireless communication terminal participates in the TWT operation. In this case, the predetermined value may be a reserved value not allocated for other purposes. For example, the predetermined value may be 2044. More specifically, the base station wireless communication terminal may set the value of the AID12 sub-field in the user information field transmitted at the TWT as shown in Figure 30 in 2) of. When the value of the AID12 sub-field in the user information field of the trigger frame received by the wireless communication terminal is the predetermined value, the wireless communication terminal that is only used to exchange frames with the base station wireless communication terminal in the TWT SP attempts random access in the RU indicated by the corresponding user information field.

[0284] In another specific embodiment, the base station wireless communication terminal may set the value of a specific sub-field in the trigger-related user information field of the user information field of the trigger frame transmitted at the TWT to a predetermined value. In this case, the specific sub-field of the trigger-related user information field may be the TID aggregation limit field. In this case, the TID aggregation limit field may be a field for indicating the limit on the number of TIDs corresponding to the data that can be aggregated in the A-MPDU transmitted based on the trigger frame. For example, the base station wireless communication terminal may set the value of the TID aggregation limit field to six. More specifically, the base station wireless communication terminal may set the TID aggregation limit field in the trigger-related user information field of the trigger frame transmitted in the TWT as shown in Figure 30 in 3) of. Additionally, the specific sub-field of the trigger-related user information field may be one of the reserved fields. When the value of the specific sub-field in the trigger-related user information field of the user information field received by the wireless communication terminal is the predetermined value, the wireless communication terminal that is only used to exchange frames with the base station wireless communication terminal in the TWT SP may attempt random access in the RU indicated by the corresponding user information field.

[0285] In the above embodiments, the wireless communication terminal that is to exchange frames with the base station wireless communication terminal in the TWT SP may only send a frame indicating that the wireless communication terminal is in the wake-up state by using random access. In this case, the frame indicating that the wireless communication terminal is in the wake-up state may be a PS poll frame or a U-APSD trigger frame.

[0286] Figure 31 Illustrates a wireless communication terminal setting MU EDCA parameters in a TWT operation according to an embodiment of the present invention.

[0287] In the TWT operation, a wireless communication terminal can perform an Opportunistic Power Saving (OPS) operation under a predetermined condition. The base station wireless communication terminal sets the TWT stream identifier field to three so that it can indicate that the base station wireless communication terminal supports the OPS operation. The base station wireless communication terminal can use the TIME element at the start time point of the OPS TWT SP to signal the scheduling information for all wireless communication terminals participating in the OPS TWT. The base station wireless communication terminal deactivates the bit corresponding to the AID of the wireless communication terminal in the bitmap of the TIM element to indicate the wireless communication terminal for which transmission is not scheduled in the corresponding OPS TWT. Also, for a wireless communication terminal not participating in the OPS TWT, the base station wireless communication terminal can signal in the same way as the existing TIM element. The wireless communication terminal for which transmission is not scheduled in the corresponding OPS TWT can remain in the sleep state until the next OPS TWT. When the corresponding wireless communication terminal needs additional uplink transmission, the corresponding wireless communication terminal can attempt UL SU transmission by operating EDCA separately.

[0288] In this case, when a wireless communication terminal uses a MU EDCA parameter set, the wireless communication terminal may not expect UL MU scheduling, and the probability of successful channel access of the wireless communication terminal may be too low. Therefore, a situation may occur where the wireless communication terminal cannot send data to be urgently sent. In a specific embodiment, when the wireless communication terminal receives a TIM element including a bitmap in which a bit corresponding to the wireless communication terminal is deactivated in the OPS TWT SP, the wireless communication terminal may stop using the MU EDCA parameter set. More specifically, when the wireless communication terminal receives a TIM element including a bitmap in which a bit corresponding to the wireless communication terminal is deactivated in the OPS TWT SP, the wireless communication terminal may set the MUEDCA timer to 0. In a specific embodiment, more specifically, when the wireless communication terminal receives a TIM element including a bitmap in which a bit corresponding to the wireless communication terminal is deactivated in the OPS TWT SP, the wireless communication terminal may stop applying the MU EDCA parameter set for the AC whose value of the MU EDCA timer is faster than that of the next OPS TWT. In a specific embodiment, more specifically, when the wireless communication terminal receives a TIM element including a bitmap in which a bit corresponding to the wireless communication terminal is deactivated in the OPS TWT SP, the wireless communication terminal may set the MU EDCA timer to 0 at the AC whose value of the MU EDCA timer is faster than that of the next OPS TWT. This is because there may be too many wireless communication terminals for which UL transmissions are not scheduled in the OPS TWT SP. Accordingly, this is because when all wireless communication terminals that are not scheduled for UL transmission stop applying the MU EDCA parameter, the probability of channel access of the base station wireless communication terminal may be too low.

[0289] In the above embodiment, when the wireless communication terminal stops applying the MU EDCA parameter set, the wireless communication terminal may set the EDCA parameter set according to the most recently received EDCA parameter set element. When the wireless communication terminal does not receive an EDCA parameter set element, the wireless communication terminal may set the EDCA parameter set according to the default EDCA parameter set.

[0290] In Figure 31 the embodiment of, the first station STA1 applies the MU EDCA parameter set. The first station STA1 receives a TIM / FILS discovery frame including a TIM element from the AP. In this case, the bit corresponding to the first station STA1 in the bitmap of the TIM element is set to 0. Therefore, the wireless communication terminal stops applying the MU EDCA parameter set by setting the MU EDCA parameters of all ACs to 0.

[0291] Figure 32Shows the operation of a base station wireless communication terminal and a wireless communication terminal according to an embodiment of the present invention.

[0292] The base station wireless communication terminal 3201 transmits a PPDU including a trigger frame for triggering the transmission of at least one wireless communication terminal 3203 (S3201). More specifically, the base station wireless communication terminal 3201 may generate a trigger frame for triggering the random access based on uplink transmission of at least one wireless communication terminal 3203, and may insert and transmit the trigger frame. In this case, the trigger frame may trigger the random access based on uplink transmission of a wireless communication terminal 3203 that is not associated with the BSS operated by the base station wireless communication terminal 3201.

[0293] When the trigger frame triggers the random access based on uplink transmission of a wireless communication terminal 3203 that is not associated with the BSS operated by the base station wireless communication terminal 3201, the base station wireless communication terminal 3201 may use a PPDU format including a field indicating the BSS color to transmit the PPDU including the trigger frame. More specifically, when the trigger frame triggers the random access based on uplink transmission of a wireless communication terminal 3203 that is not associated with the BSS operated by the base station wireless communication terminal 3201, the base station wireless communication terminal 3201 may insert the trigger frame into the HE PPDU. In the above embodiment, the method for setting the value of the field indicating the BSS color may follow the embodiment described in the reference Figures 14 to 15 described embodiment.

[0294] In addition, when the trigger frame triggers the random access of a wireless communication terminal 3203 that is not associated with the BSS operated by the base station wireless communication terminal 3201, the base station wireless communication terminal 3201 may insert a field indicating the BSS color into the trigger frame. In this case, the base station wireless communication terminal 3201 may insert the field indicating the BSS color into the user information field that signals information separately applied to one or more wireless communication terminals 3203 for which the frame trigger transmission. In another specific embodiment, the base station wireless communication terminal 3201 may insert the field indicating the BSS color into the common information field that signals information generally applied to one or more wireless communication terminals 3203 for which the trigger frame triggers transmission.

[0295] The base station wireless communication terminal 3201 may set a specific field of the trigger frame to a predetermined AID value so that it can trigger the random access of a wireless communication terminal 3203 that is not associated with the BSS operated by the base station wireless communication terminal 3201.

[0296] The base station wireless communication terminal 3201 may be based on the reference Figure 16The described embodiment triggers a random access based on an uplink transmission of a wireless communication terminal 3203 that is not associated with a BSS operated by a base station wireless communication terminal 3201.

[0297] In addition, the base station wireless communication terminal 3201 may send a trigger frame based on a predetermined schedule. More specifically, the base station wireless communication terminal 3201 may send a trigger frame according to the above-described TWT operation. The trigger frame may trigger a transmission based on a random access uplink of a wireless communication terminal 3203 that performs a power saving operation based on a predetermined schedule. In this case, the wireless communication terminal 3203 that performs a power saving operation based on a predetermined schedule may remain in a sleep state until the TWT and change to a wake state in the TWT, as described above. The base station wireless communication terminal 3201 may set the receiver address field of the trigger frame to a group address that indicates that the wireless communication terminal 3203 performs a power saving operation based on a predetermined schedule. In another specific embodiment, the base station wireless communication terminal 3201 may set the AID value indicated by the user information field corresponding to the band allocated for random access based on an uplink transmission to a predetermined value that indicates the wireless communication terminal 3203 that performs a power saving operation based on a predetermined schedule. For example, the predetermined value may be 2044. In this case, the predetermined value may be a reserved value that is not allocated for other purposes. In another specific embodiment, the base station wireless communication terminal 3201 sets one of the values of the fields determined according to the type of the trigger frame of the user information field corresponding to the band allocated for random access based on an uplink transmission to a predetermined value that indicates the wireless communication terminal 3203 that performs a power saving operation based on a predetermined schedule. The base station wireless communication terminal 3201 sets the TID aggregation limit field included in the user information field corresponding to the band allocated for random access based on an uplink transmission to a predetermined value that indicates the wireless communication terminal 3203 that performs a power saving operation based on a predetermined schedule. In this case, the TID aggregation limit field may be a field for indicating a limit on the number of TIDs corresponding to the data that can be aggregated in an A-MPDU transmitted based on the trigger frame. Specifically, the base station wireless communication terminal 3201 may operate as in the embodiment described in reference to Figures 30 to 31 the described embodiment.

[0298] The wireless communication terminal 3203 receives a PPDU including a trigger frame from the base station wireless communication terminal 3201, and the trigger frame triggers the transmission to the base station wireless communication terminal 3201. The wireless communication terminal 3203 sends a trigger-based PPDU to the base station wireless communication terminal 3201 based on the trigger frame (S3203). When the PPDU including the trigger frame indicates a basic service set (BSS) color, the wireless communication terminal 3203 may set the value of the BSS color indicated by the trigger-based PPDU based on the value of the BSS color indicated by the PPDU including the trigger frame. If the PPDU including the trigger frame does not indicate a BSS color, the wireless communication terminal 3203 may set the value of the BSS color indicated by the trigger-based PPDU according to the effective BSS color of the wireless communication terminal 3203. In this case, the effective BSS color may indicate the BSS color actually used by the wireless communication terminal 3203 as described above. In this embodiment, the wireless communication terminal 3203 may receive information about the BSS color change from the base station wireless communication terminal. Additionally, when reaching the BSS color change time point indicated by the information about the BSS color change, the wireless communication terminal 3203 may set the effective BSS color to the value of the BSS color indicated by the information about the BSS color change. In this case, the BSS color change time point may be set based on the target beacon transmission time sent by the base station wireless communication terminal. Additionally, the specific operations of the wireless communication terminal 3203 may follow the embodiments described with reference to Figures 22 to 23 the embodiments described.

[0299] When the PPDU indicates a partial BSS color, when the value of the partial AID is non-zero, the wireless communication terminal 3203 may determine whether the PPDU is an intra-BSS PPDU or an inter-BSS PPDU based on the value of the partial BSS color. In this case, the specific operations of the wireless communication terminal 3203 may follow the embodiments described with reference to Figures 18 to 19 the embodiments described. Embodiments in which the wireless communication terminal 3203 determines whether an intra-BSS or intra-BSS can be applied to a PPDU that does not include a trigger frame and when a PPDU including a trigger frame as described above is received.

[0300] Although the present invention is described by using wireless LAN communication as an example, the present invention is not limited thereto and can be applied to other communication systems such as cellular communication. Additionally, although the methods, devices, and systems of the present invention are described according to specific embodiments of the present invention, some or all components or operations of the present invention can be implemented by using a computer system having a general hardware architecture.

[0301] The features, structures, and effects described in the above embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. In addition, those skilled in the art can combine or improve the features, structures, and effects shown in each embodiment in other embodiments. Therefore, it should be understood that the content related to such combinations and improvements is included within the scope of the present invention.

[0302] Although the present invention is mainly described based on the above embodiments, it is not limited thereto. However, those skilled in the art will understand that various changes and improvements can be made without departing from the spirit and scope of the present invention. For example, each component specifically shown in the embodiments can be modified and implemented. It should be understood that the differences related to such modifications and applications are included within the scope of the present invention defined by the appended claims.

Claims

1. A wireless communication terminal that wirelessly communicates with a base station wireless communication terminal, the wireless communication terminal comprising: a transceiver configured to transmit and receive wireless signals; and a processor configured to process the wireless signals, wherein the processor is configured to: receive a physical layer protocol data unit (PPDU) including a trigger frame for triggering a transmission to the base station wireless communication terminal, wherein the trigger frame includes an identifier identifying the wireless communication terminal triggered by the trigger frame, and the trigger frame indicates a resource unit (RU) allocated to the wireless communication terminal, when the PPDU uses a signaling field of the PPDU to indicate a basic service set (BSS) color, set a value of the BSS color to be indicated by the trigger-based PPDU based on a value of the BSS color indicated by the PPDU including the trigger frame, when the signaling field of the PPDU does not indicate the BSS color, set a value of the BSS color to be indicated by the trigger-based PPDU according to a valid BSS color of the wireless communication terminal, and transmit the trigger-based PPDU based on the trigger frame, wherein the BSS color is one of the identifiers identifying the BSS, wherein when the wireless communication terminal receives information about a BSS color change from the base station wireless communication terminal and reaches a BSS color change time point indicated by the information about the BSS color change, the valid BSS color is a value of the BSS color indicated by the information about the BSS color change.

2. The wireless communication terminal according to claim 1, wherein, The BSS color change time point is set based on a target beacon transmission time sent by the base station wireless communication terminal.

3. The wireless communication terminal according to claim 1, wherein, If the PPDU uses a partial association ID (AID) field to indicate a partial basic service set (BSS) color, when a value of the partial AID field is non-zero, the processor determines whether the PPDU is a BSS-internal PPDU or a BSS-inter PPDU based on the partial BSS color, wherein the partial AID field is a signaling field for indicating a part of the AID value, wherein the BSS-internal PPDU is a PPDU sent from a BSS including the wireless communication terminal, and the BSS-inter PPDU is a PPDU sent from a BSS not including the wireless communication terminal.

4. A method of operating a wireless communication terminal that wirelessly communicates with a base station wireless communication terminal, the method comprising: receiving a physical layer protocol data unit (PPDU) including a trigger frame for triggering a transmission to the base station wireless communication terminal, wherein the trigger frame includes an identifier identifying the wireless communication terminal triggered by the trigger frame, and the trigger frame indicates a resource unit (RU) allocated to the wireless communication terminal, When the PPDU uses the signaling field of the PPDU to indicate the Basic Service Set (BSS) color, set the value of the BSS color to be indicated by the trigger-based PPDU based on the value of the BSS color indicated by the PPDU including the trigger frame. When the signaling field of the PPDU does not indicate the BSS color, set the value of the BSS color to be indicated by the trigger-based PPDU according to the effective BSS color of the wireless communication terminal, and Transmit the trigger-based PPDU based on the trigger frame, wherein the BSS color is one of the identifiers in the identifier for identifying the BSS, wherein when the wireless communication terminal receives information about the BSS color change from the base station wireless communication terminal and reaches the BSS color change time point indicated by the information about the BSS color change, the effective BSS color is the value of the BSS color indicated by the information about the BSS color change.

5. The method according to claim 4, wherein The BSS color change time point is set based on the target beacon transmission time sent by the base station wireless communication terminal.

6. The method according to claim 4, the method further comprising Among them, If the PPDU uses the partial Association ID (AID) field to indicate the partial Basic Service Set (BSS) color, when the value of the partial AID field is non-zero, determine whether the PPDU is a BSS-in PPDU or a BSS-between PPDU based on the partial BSS color, wherein the partial AID field is a signaling field for indicating a part of the AID value, wherein the BSS-in PPDU is a PPDU sent from the BSS including the wireless communication terminal, and the BSS-between PPDU is a PPDU sent from a BSS not including the wireless communication terminal.

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