Wireless communication method and wireless communication terminal using OFDM random access

Abstract

A wireless communication method and a wireless communication terminal using OFDM random access are disclosed. The wireless communication terminal includes a transmitting / receiving unit and a processor. The processor sets an integer selected from a range of 0 to a value equal to or less than an OFDMA contention window (OCW) as a counter for random access, receives a trigger frame for triggering random access from a base station wireless communication terminal through the transmitting / receiving unit using one or more resource units (RUs) allocated to random access, decrements the value of the counter based on the one or more RUs allocated to random access, randomly selects one or more RUs allocated to random access when the value of the counter is 0 or becomes 0, and attempts to use the selected RU for transmission to the base station wireless communication terminal. At this time, RU is a group of multiple subcarriers that can be used for uplink transmission and downlink transmission.

Description

[0001] This application is a divisional application of a patent application with application number 201780080498.9 (PCT / KR2017 / 015535), which was submitted to the China Patent Office on June 25, 2019, with an international application date of December 27, 2017, and the invention name is "Wireless communication method using OFDM random access and wireless communication terminal using the method". Technical Field

[0002] The present invention relates to a wireless communication method and a wireless communication terminal using OFDMA random access. Background Art

[0003] In recent years, as the supply of mobile devices has expanded, wireless communication technology that can provide fast wireless Internet services to mobile devices has significantly attracted public attention. Wireless communication technology allows mobile devices including smart phones, smart boards, laptops, portable multimedia players, embedded devices, etc. to access the Internet wirelessly in homes or companies or specific service provision areas.

[0004] One of the most famous wireless communication technologies is wireless LAN technology. Since the use of 2.4GHz frequency to support the initial wireless LAN technology, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 has been commercialized or developed various technical standards. First, IEEE 802.11b supports a maximum communication speed of 11Mbps when using the frequency of the 2.4GHz band. The IEEE 802.11a commercialized after IEEE802.11b uses a frequency of the 5GHz band instead of the 2.4GHz band, which reduces the impact of interference compared to the obviously congested frequency of the 2.4GHz band, and increases the communication speed by using orthogonal frequency division multiplexing (OFDM) technology until a maximum of 54Mbps. However, the reason why IEEE 802.11a has a disadvantage is that the communication distance is shorter than IEEE802.11b. Furthermore, IEEE 802.11g uses a frequency of 2.4 GHz band similarly to IEEE 802.11b to achieve a maximum communication speed of 54 Mbps and satisfy backward compatibility to be significantly noticed by the public, and further, 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 LAN, IEEE 802.11n has been provided. IEEE 802.11n aims to improve the speed and reliability of the network and extend the working distance of the wireless network. In more detail, IEEE 802.11n supports high throughput (HT) with a data processing speed of up to 540Mbps or higher, and further, multiple input multiple output (MIMO) technology based on multiple antennas is used on both sides of the transmitting unit and the receiving unit to minimize transmission errors and optimize data speed. In addition, the standard can use a coding scheme that sends multiple copies overlapping each other to improve data reliability.

[0006] As the supply of wireless LANs is active and the applications using wireless LANs are further diversified, the need for new wireless LAN systems for supporting 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 160MHz) of 5GHz frequency. The IEEE 802.11ac standard is defined only in the 5GHz band, but the initial 11ac chipset will even support operations in the 2.4GHz band for backward compatibility with existing 2.4GHz band products. Theoretically, according to the standard, the wireless LAN speed of multiple stations can reach a maximum of 1Gbps and the maximum single link speed can reach a maximum of 500Mbps. This is achieved by expanding the concept of the wireless interface accepted by 802.11n, such as a wider wireless frequency bandwidth (maximum 160MHz), more MIMO spatial streams (maximum 8), multi-user MIMO and high-density modulation (maximum 256QAM). In addition, as a scheme for transmitting data by using the 60 GHz band instead of the existing 2.4 GHz / 5 GHz, IEEE 802.11ad has been provided. IEEE 802.11ad is a transmission standard that provides a maximum speed of 7 Gbps by using a beamforming technology and is suitable for high-bitrate moving image streams such as massive data or non-compressed HD video. However, since the 60 GHz band is difficult to pass through obstacles, the disadvantage is that the 60 GHz band can be used only between devices in 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 a high-density environment are ongoing. 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 the communication are required.

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

[0009] Technical issues

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

[0011] Technical Solution

[0012] According to an embodiment of the present invention, a wireless communication terminal for wireless communication with a base station wireless communication terminal includes a transceiver and a processor. The processor is configured to set an integer selected from a range of 0 to a value equal to or less than an OFDMA contention window (OCW) as a counter for random access, use the transceiver to receive a trigger frame for triggering random access using one or more resource units (RUs) allocated to the random access from the base station wireless communication terminal, decrement the value of the counter based on the one or more RUs allocated for random access, randomly select one or more RUs allocated for random access when the value of the counter is 0 or reaches 0, and attempt to use the selected RU for transmission to the base station wireless communication terminal. In this case, RU is a group of multiple subcarriers that can be used for uplink transmission and downlink transmission.

[0013] The processor may be configured to decrement the value of the counter based on one or more RUs allocated for random access and the capability of the wireless communication terminal.

[0014] The processor may be configured to decrement the value of the counter by the number of RUs through which the wireless communication terminal can transmit the TB PPDU according to the capability of the wireless communication terminal among the one or more RUs allocated for random access.

[0015] When the value of the counter is 0 or reaches 0, the processor may be configured to randomly select any one of the RUs allocated for random access and through which the wireless communication terminal can transmit the TB PPDU according to the capability of the wireless communication terminal.

[0016] The capabilities of a wireless communication terminal include capabilities related to a bandwidth over which the wireless communication terminal can perform transmissions.

[0017] The capabilities of the wireless communication terminal may include capabilities related to the length of a padding field included in a TB PPDU.

[0018] The capabilities of the wireless communication terminal may include capabilities related to modulation and coding schemes that the wireless communication terminal is capable of performing transmissions.

[0019] The wireless communication terminal may be a wireless communication terminal that is not associated with the base station wireless communication terminal. The processor may be configured to set the OCW minimum value, which is a parameter indicating the minimum value of the OCW, to a value predetermined as a default value of the OCW minimum value, and to set the OCW maximum value, which is a parameter indicating the maximum value of the OCW, to a value predetermined as a default value of the OCW maximum value. In this case, the value predetermined as the default value of the OCW minimum value and the value predetermined as the default value of the OCW maximum value may not be a value specified by the base station wireless communication terminal.

[0020] The wireless communication terminal may be a wireless communication terminal that is not associated with the base station wireless communication terminal. When the wireless communication terminal communicates with a different base station wireless communication terminal that is different from the base station wireless communication terminal, the processor may be configured to initialize parameters for random access to the different wireless communication terminal. In this case, the parameters for random access may include a counter, an OCW minimum value as a parameter indicating a minimum value of the OCW, and an OCW maximum value as a parameter indicating a maximum value of the OCW.

[0021] When the wireless communication terminal communicates with a base station wireless communication terminal, the processor may be configured to set the OCW minimum value and the OCW maximum value according to information received from the base station wireless communication terminal. In this case, when the wireless communication terminal communicates with different base station wireless communication terminals, the processor may be configured to set the OCW minimum value and the OCW maximum value according to information received from different base station wireless communication terminals.

[0022] The wireless communication terminal is associated with a base station wireless communication terminal. In this case, the processor may be configured to set an OCW minimum value as a parameter indicating a minimum value of the OCW and an OCW maximum value as a parameter indicating a maximum value of the OCW according to information received from a base station wireless communication terminal different from the base station wireless communication terminal. In addition, different base station wireless communication terminals may belong to a plurality of basic service set identification (BSSID) sets to which the base station wireless communication terminal belongs.

[0023] The processor may be configured to not decrement the value of the counter based on a trigger frame sent from a different base station wireless communication terminal.

[0024] The different base station wireless communication terminals may be base station wireless communication terminals operating a BSS corresponding to the transmitted basic service set identifier (BSSID) of the multiple BSSID set.

[0025] The information received by the wireless communication terminal from a different base station may not be information indicated in a signaling field allocated for the BSS including the wireless communication terminal.

[0026] When the trigger frame indicates an uplink transmission of the wireless communication terminal, the processor may be configured not to decrement the value of the counter based on the trigger frame.

[0027] According to an embodiment of the present invention, a method of operating a wireless communication terminal that wirelessly communicates with a base station wireless communication terminal includes: setting an integer selected from a range of 0 to a value equal to or less than an OFDMA contention window (OCW) as a counter for random access; receiving a trigger frame for triggering random access using one or more resource units (RUs) allocated for random access from the base station wireless communication terminal; decrementing the value of the counter based on the one or more RUs allocated for random access; randomly selecting one or more RUs allocated for random access when the value of the counter is 0 or reaches 0; and attempting to use the selected RU for transmission to the base station wireless communication terminal. In this case, the RU is a group of multiple subcarriers that can be used for OFDM communication.

[0028] Decreasing the value of the counter may include decrementing the value of the counter based on one or more RUs allocated for random access and a capability of the wireless communication terminal.

[0029] Decreasing the value of the counter based on one or more RUs allocated for random access and the capabilities of the wireless communication terminal may include decrementing the value of the counter by the number of RUs among the one or more RUs allocated for random access through which the wireless communication terminal sends a TB PPDU according to the capabilities of the wireless communication terminal.

[0030] Randomly selecting one or more RUs allocated for random access may include randomly selecting any one of the RUs that is allocated for random access and through which the wireless communication terminal can send the TBPPDU according to the capability of the wireless communication terminal.

[0031] The wireless communication terminal may be a wireless communication terminal not associated with the base station wireless communication terminal. The operation method may further include: setting the OCW minimum value as a parameter indicating the minimum value of the OCW to a value predetermined as a default value of the OCW minimum value, and setting the OCW maximum value as a parameter indicating the maximum value of the OCW to a value predetermined as a default value of the OCW maximum value. In addition, the value predetermined as the default value of the OCW minimum value and the value predetermined as the default value of the OCW maximum value may not be a value specified by the base station wireless communication terminal.

[0032] Beneficial Effects

[0033] Embodiments of the present invention provide a wireless communication method using OFDMA random access and a wireless communication terminal using the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A wireless LAN system according to an embodiment of the present invention is shown.

[0035] Figure 2 A wireless LAN system according to another embodiment of the present invention is shown.

[0036] Figure 3 A block diagram illustrating a configuration of a station according to an embodiment of the inventive concept is shown.

[0037] Figure 4 A block diagram illustrating a configuration of an access point according to an embodiment of the present invention is shown.

[0038] Figure 5 The process of a station setting up an access point and a link according to an embodiment of the present invention is shown.

[0039] Figure 6 UL MU transmission of a wireless communication terminal according to an embodiment of the present invention is shown.

[0040] Figure 7 A specific trigger frame format according to an embodiment of the present invention is shown.

[0041] Figure 8 The specific formats of the common information field and the user information field of the trigger frame according to an embodiment of the present invention are shown.

[0042] Fig. 9 A random access operation of a wireless communication terminal according to an embodiment of the present invention is shown.

[0043] Fig.10 A specific format of a UORA parameter set element according to an embodiment of the present invention is shown.

[0044] Fig.11 A specific format of multiple BSSID elements according to an embodiment of the present invention is shown.

[0045] Figures 12 to 13 A random access operation of a wireless communication terminal associated with a multiple BSSID set according to an embodiment of the present invention is shown.

[0046] Fig.14 Shown are the types of RUs and subcarrier indexes that can be used when sending a PPDU with a 20 MHz bandwidth according to an embodiment of the present invention.

[0047] Fig.15Shown are the types of RUs and subcarrier indexes that can be used when sending a PPDU with a 40 MHz bandwidth according to an embodiment of the present invention.

[0048] Fig.16 Shown are the types of RUs and subcarrier indexes that can be used when sending a PPDU with an 80 MHz bandwidth according to an embodiment of the present invention.

[0049] Fig.17 The coding value of the RU in the RU allocation subfield of the trigger frame is shown according to an embodiment of the present invention.

[0050] Figures 18 to 19 It is shown that a wireless communication terminal that only supports PPDU with a bandwidth of 20 MHz performs a random access operation according to an embodiment of the present invention.

[0051] Figures 20 to 21 It is shown that a wireless communication terminal that only supports PPDU having a bandwidth of 80 MHz or less performs a random access operation according to an embodiment of the present invention.

[0052] Fig. 22 A random access operation of a non-associated wireless communication terminal according to an embodiment of the present invention is shown.

[0053] Fig.23 A random access operation of a non-associated wireless communication terminal according to an embodiment of the present invention is shown.

[0054] Fig.24 A random access operation of a non-associated wireless communication terminal according to an embodiment of the present invention is shown.

[0055] Fig.25 A random access operation of a non-associated wireless communication terminal according to an embodiment of the present invention is shown.

[0056] Fig.26 A random access operation of a wireless communication terminal when the wireless communication terminal according to an embodiment of the present invention schedules uplink transmission through a triggered frame is shown. Fig. 27 A conventional PPDU format according to an embodiment of the present invention is shown.

[0057] Fig.28 A non-legacy PPDU format according to an embodiment of the present invention is shown.

[0058] Fig.29 The coverage of the HE extended range SU PPDU and the transmission coverage of the conventional PPDU according to an embodiment of the present invention are shown.

[0059] Fig.30 The dual beacon transmission operation of the base station wireless communication terminal according to the embodiment of the present invention is shown.

[0060] Fig.31 The format of the BSS color change declaration element according to an embodiment of the present invention is shown.

[0061] Fig.32 A BSS color change operation of a base station wireless communication terminal when the base station wireless communication terminal uses dual beacons according to an embodiment of the present invention is shown.

[0062] Fig.33 A BSS color change operation of a base station wireless communication terminal when the base station wireless communication terminal uses dual beacons according to another embodiment of the present invention is shown.

[0063] Fig.34 A BSS color change operation of a base station wireless communication terminal when the base station wireless communication terminal uses dual beacons according to another embodiment of the present invention is shown.

[0064] Fig.35 The format of the A-MPDU according to an embodiment of the present invention is shown.

[0065] Fig.36 A specific format of Block Ack according to an embodiment of the present invention is shown.

[0066] Fig.37 A per-STA information subfield according to an embodiment of the present invention is shown.

[0067] Fig.38 The context of the Per-STA Information subfield according to an embodiment of the present invention is shown.

[0068] Figures 39 to 40 An A-MPDU configuration according to an embodiment of the present invention is shown.

[0069] Fig.41 The operation of the wireless communication terminal according to the embodiment of the present invention is shown. DETAILED DESCRIPTION

[0070] The 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 specifically implemented in different forms and should not be constructed to be limited to the embodiments set forth herein. Parts that are irrelevant to the description are omitted in the accompanying drawings in order to clearly describe the present invention, and similar reference numerals refer to similar elements from beginning to end.

[0071] Furthermore, when it is described that a thing includes (or contains or has) some elements, it should be understood that, without specific limitations, 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.

[0072] This application claims priority to and the benefits of Korean Patent Applications Nos. 10-2016-0179781 (2016.12.27), 10-2017-0000020 (2017.01.02), 10-2017-0000437 (2017.01.02), 10-2017-0002195 (2017.01.06), and 10-2017-0002720 (2017.01.09) filed in the Korean Intellectual Property Office, and the embodiments and items mentioned in the corresponding applications are included in the detailed description of this application.

[0073] Figure 1 1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. For the convenience of description, the embodiment of the present invention is described through a wireless LAN system. The wireless LAN system includes one or more basic service sets (BSSs) and the BSS represents a collection of devices that are successfully synchronized with each other to communicate with each other. In general, the BSS can be classified into an infrastructure BSS and an independent BSS (IBSS) and Figure 1 The diagram shows the infrastructure BSS between them.

[0074] like Figure 1 As illustrated in the figure, the infrastructure BSS (BSS1 and BSS2) includes one or more stations STA1, STA2, STA3, STA4 and STA5, access points PCP / AP-1 and PCP / AP-2 as stations providing distribution services, and a distribution system (DS) connecting multiple access points PCP / AP-1 and PCP / AP-2.

[0075] A station (STA) is a predetermined device including a media access control (MAC) and a physical layer interface for a wireless medium that follows the procedures of the IEEE 802.11 standard, and includes a non-access point (non-AP) station and an access point (AP) in a broad sense. In addition, in this specification, the term "terminal" may be used to refer to the concept of a wireless LAN communication device including such as a non-AP STA or 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 a frame to be sent through a wireless network or process a frame received through a wireless network, and further, perform various processes for controlling the station. In addition, the transceiver is functionally connected to the processor and sends and receives frames through a wireless network for a station.

[0076] An access point (AP) is an entity that provides access to a distribution system (DS) for stations associated therewith via a wireless medium. In an infrastructure BSS, communication between non-AP stations is performed via an AP in principle, but when a direct link is configured, direct communication can be achieved even between non-AP stations. Meanwhile, in the present invention, AP is used as a concept including a personal BSS coordination point (PCP) and may include concepts including a centralized controller, a base station (BS), a node B, a base transceiver system (BTS), and a site controller in a broad sense.

[0077] Multiple infrastructure BSSs may be connected to each other through a distribution system (DS). In this case, the multiple BSSs connected through the distribution system are referred to as an extended service set (ESS).

[0078] Figure 2 The figure shows an independent BSS as a wireless communication system according to another embodiment of the present invention. For the convenience of description, another embodiment of the present invention is described by a wireless LAN system. Figure 2 In the embodiment of Figure 1 The same or corresponding parts of the embodiments are described repeatedly.

[0079] because Figure 2 The BSS3 shown in FIG. 1 is an independent BSS and does not include an AP, so all stations STA6 and STA7 are not connected to the AP. An independent BSS is not allowed to access the distribution system and form a complete network. In an independent BSS, corresponding stations STA6 and STA7 can be directly connected to each other.

[0080] Figure 3 is a block diagram illustrating a configuration of a station 100 according to an embodiment of the present invention.

[0081] like Figure 3 As illustrated in FIG. 1 , 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 .

[0082] 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 to the outside. According to the embodiment, the transceiver 120 may include at least one transmission and reception module using different frequency bands. For example, the transceiver 120 may include transmission and reception modules with different frequency bands such as 2.4GHz, 5GHz and 60GHz. According to the embodiment, the station 100 may include a transmission and reception module using a frequency band of 6GHz or higher and a transmission and reception module using a frequency band of 6GHz or lower. The corresponding transmission and reception module can perform wireless communication with an AP or an external station according to the wireless LAN standard of the frequency band supported by the corresponding transmission and reception module. The transceiver 120 can operate only one transmission and reception module at a time or operate multiple transmission and reception modules simultaneously together according to the performance and requirements of the station 100. When the station 100 includes multiple transmission and reception modules, each transmission and reception module can be implemented by an independent element or multiple modules can be integrated into one chip.

[0083] 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 a 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 an output based on a command of the processor 110 by using various output devices.

[0084] Next, the display unit 150 outputs an image on the display screen. The display unit 150 may output various display objects such as content or a user interface executed by the processor 110 based on a control command of the processor 110 or the like. In addition, the memory 160 stores a control program used in the station 100 and various resulting data. The control program may include an access program required for the station 100 to access an AP or an external station.

[0085] The processor 110 of the present invention may execute various commands or programs and process data in the station 100. In addition, the processor 110 may control the 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. In addition, the processor 110 may read information about the priority condition of the station 100 included in the communication configuration message and request access to the AP based on the information about the priority condition of the station 100. The processor 110 of the present invention may represent a main control unit of the station 100 and according to this embodiment, the processor 110 may represent a control unit for individually controlling a certain component (e.g., transceiver 120, etc.) of the station 100. The processor 110 may be a modulator and / or demodulator that modulates a wireless signal sent to the transceiver 120 and demodulates a wireless signal received from the transceiver 120. The processor 110 controls various operations of wireless signal transmission / reception of the station 100 according to an embodiment of the present invention. A detailed embodiment thereof will be described below.

[0086] Figure 3 The station 100 illustrated in is a block diagram according to an embodiment of the present invention, in which individual blocks are illustrated as logically distinct elements of the device. Therefore, the elements of the device can 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 can be integrated into a single chip or implemented as separate chips. In addition, in an embodiment of the present invention, some components of the station 100, such as the user interface unit 140 and the display unit 150, can be optionally set in the station 100.

[0087] Figure 4 is a block diagram illustrating a configuration of an AP 200 according to an embodiment of the present invention.

[0088] like Figure 4 As shown in FIG. 2 , the AP 200 according to an embodiment of the present invention may include a processor 210, a transceiver 220, and a memory 260. Figure 4 In the AP 200, the components of Figure 2 Description of the same or corresponding parts of the components of the station 100 are repeated.

[0089] refer to Figure 4 , the AP 200 according to the present invention includes a transceiver 220 for operating a BSS in at least one frequency band. Figure 3As described in the embodiment of the present invention, the transceiver 220 of the AP 200 may also include a plurality of transmission and reception modules using different frequency bands. That is, the AP 200 according to the embodiment of the present invention may include two or more transmission and reception modules among different frequency bands (e.g., 2.4 GHz, 5 GHz, and 60 GHz) together. Preferably, the AP 200 may include a transmission and reception module using a 6 GHz or higher frequency band and a transmission and reception module using a 6 GHz or lower frequency band. The corresponding transmission and reception modules may perform wireless communication with the station according to the wireless LAN standard of the frequency band supported by the corresponding transmission and reception modules. The transceiver 220 may operate only one transmission and reception module at a time or operate a plurality of transmission and reception modules simultaneously together according to the performance and requirements of the AP 200.

[0090] Next, the memory 260 stores the control program used in the AP 200 and various resulting data. The control program may include an access program for managing the access of the station. 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 condition 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 the radio signal of the AP 200 according to the first embodiment of the present invention. Its detailed embodiment will be described below.

[0091] Figure 5 is a diagram schematically illustrating a process in which a STA sets up a link with an AP.

[0092] refer to Figure 5 , the link between the STA 100 and the AP 200 is generally set up 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. Methods for performing scanning include a passive scanning method in which the AP 200 obtains information by using a beacon message (S101) transmitted periodically and an active scanning method in which the STA 100 transmits a probe request to the AP (S103) and obtains access information by receiving a probe response (S105) from the AP.

[0093] The STA 100 that successfully receives 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 can broadly include wireless combination and wired combination.

[0094] At the same time, an authentication step (S111) based on 802.1X and an IP address acquisition step (S113) through DHCP may be additionally performed. Figure 5 In the example, the authentication server 300 is a server that processes 802.1X-based authentication for the STA 100 and may exist in physical association with the AP 200 or as a separate server.

[0095] In a specific embodiment, the AP 200 may be a wireless communication terminal that allocates communication media resources and performs scheduling in an independent network (such as an ad hoc network) that is not connected to an external distribution service. In addition, the AP 200 may be at least one of a base station, an eNB, and a transmission point TP. The TP 200 may also be referred to as a base station communication terminal.

[0096] The base station wireless communication terminal may 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 may be used as a cell coordinator. In a specific embodiment, the base station wireless communication terminal may be a wireless communication terminal that allocates and schedules communication media resources in an independent network (such as an ad hoc network) that is not connected to an external distribution service.

[0097] The base station wireless communication terminal can use orthogonal frequency division multiple access (OFDMA) or multi-user multiple input multiple output (MU-MIMO) to communicate with multiple wireless communication terminals at the same time. In this case, the base station wireless communication terminal can send trigger information to multiple wireless communication terminals to trigger uplink (UL) multi-user (MU) transmission using OFDMA of multiple wireless communication terminals. Figure 6 Describe this.

[0098] Figure 6 UL MU transmission of a wireless communication terminal according to an embodiment of the present invention is shown.

[0099] The base station wireless communication terminal may send trigger information to multiple wireless communication terminals to trigger UL MU transmission of multiple wireless communication terminals. Specifically, the base station wireless communication terminal may send trigger information to multiple wireless communication terminals to trigger multiple wireless communication terminals to send immediate response frames at the same time. In this case, the immediate response may indicate that the response frame is sent within a predetermined time from when the trigger information is received in the same transmission opportunity (TXOP). In this case, the predetermined time may be the short interframe space (SIFS) defined in the 802.11 standard. The base station wireless communication terminal is able to use a trigger frame to send trigger information. In addition, the base station wireless communication terminal may use a MAC header to send trigger information.

[0100] Multiple wireless communication terminals can use a trigger-based (TB) PPDU to send a response frame for trigger information. In this case, multiple wireless communication terminals can send a TB PPDU after a predetermined time from when the trigger information is received. In addition, multiple wireless communication terminals can use at least one of UL OFDMA and UL MU-MIMO to send the TB PPDU. When the trigger type of the trigger information is sent through a MU-Request to Send (RTS) frame, multiple wireless communication terminals are able to send a response frame for the MU-RTS frame using a non-HT PPDU.

[0101] exist Figure 6 In the embodiment of the present invention, the AP sends a trigger frame to the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4. The first station STA1, the second station STA2, the third station STA3, and the fourth station STA4 receive the trigger frame. When SIFS passes from the reception of the trigger frame, the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4 send a PPDU based on HE trigger (TB PPDU). The AP receives the PPDU based on HE trigger (TB PPDU) and sends ACK to the first station STA1, the second station STA2, the third station STA3, and the fourth station STA4.

[0102] As described above, the base station wireless communication terminal may use a trigger frame or a MAC header to send the trigger information. Specifically, the base station wireless communication terminal may use the UL MU response scheduling (UMRS) A-control subfield of the MAC header to send the trigger information. In a specific embodiment, the wireless communication terminal receiving the MAC frame including the UMRS A-control subfield sends the TB PPDU in response to the UMRS A-control subfield. In addition, the wireless communication terminal indicated by the user information field of the trigger frame may send the TB PPDU in response to the trigger frame. Reference will be made to Figure 7 Describes in detail the specific format of the trigger frame.

[0103] Figure 7 A specific trigger frame format according to an embodiment of the present invention is shown.

[0104] The trigger frame may include at least one of a frame control field, a duration field, an RA field, a TA field, a common information field, a user information field, a padding field, and an FCS field. Depending on the trigger type, the response to the trigger frame request may vary. In addition, the fields included in the trigger frame may vary depending on the trigger type.

[0105] The RA field indicates the receiver address of the trigger frame. When the trigger frame triggers the transmission of one wireless communication terminal, the RA field may indicate the MAC address of the corresponding wireless communication terminal. When the trigger frame triggers the transmission of two or more wireless communication terminals, 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 group address corresponding to the multiple wireless communication terminals triggered by the trigger frame.

[0106] The TA field indicates the transmitter address of the trigger frame. When the wireless communication terminal sending the trigger frame does not use multiple BSSIDs, the TA field may indicate the MAC address of the wireless communication terminal sending the trigger frame. In addition, when the wireless communication terminal sending the trigger frame uses multiple BSSIDs and the trigger frame triggers multiple wireless communication terminals of the multi-BSSID set, the TA field may indicate the BSSID of the wireless communication of the multi-BSSID set sent by the terminal sending the trigger frame. In this case, the transmitted BSSID indicates the BSS that can send information about other BSSs included in the multi-BSSID set with a signal. The identifier of the BSS that does not correspond to the transmitted BSSID among the BSSs included in the multi-BSSID set is the unsent BSSID. Specifically, the base station wireless communication terminal operating the BSS corresponding to the transmitted BSSID can use multiple BSSID elements to send information about the BSS corresponding to the unsent BSSID with a signal. The management frame sent from the BSS corresponding to the transmitted BSSID may include multiple BSSID elements. In this case, the management frame may include a beacon frame and a probe response frame. In addition, the transmitted BSSID may exist for each multi-BSSID set. Reference Fig.11 This is described in more detail.

[0107] The common information field indicates information generally required for at least one wireless communication terminal triggered by the trigger frame to send a response to the trigger frame. The user information field indicates information required for each of the multiple wireless communication terminals indicated by the trigger frame to send a response to the trigger frame. Specifically, the trigger frame may include multiple user information fields. Figure 8 Describes the specific format of the common fields and user information fields.

[0108] The padding field includes padding bits. Specifically, the padding field can help ensure that the wireless communication terminal that sends the response frame to the trigger frame is ready to respond to the frame transmission time. Therefore, the length of the padding field can be determined according to the capability of the wireless communication terminal that sends the response frame to the trigger frame. In addition, the trigger frame may not include the padding field. The padding field can indicate the beginning of the padding field with a predetermined value. In this case, the predetermined value can be 0xFFF. In addition, the remaining fields of the padding field except the padding field including the predetermined value can include a value other than the predetermined value or a predetermined value.

[0109] The specific format of the trigger frame can be Figure 7 The format of the embodiments is the same.

[0110] Figure 8 The specific formats of the common information field and the user information field of the trigger frame according to an embodiment of the present invention are shown.

[0111] Specifically, the format of the public information field and the format of the user information field according to the embodiment of the present invention can be respectively Figure 8 (a) and Figure 8 (b) is the same. The user information field may indicate a wireless communication terminal triggered by a trigger frame. Specifically, when the user information field includes an association identifier (AID) of a wireless communication terminal or a portion of an AID, the wireless communication terminal corresponding to the AID may determine that the trigger frame triggers the wireless communication terminal. In a specific embodiment, the AID12 subfield in the user information field may indicate the 12 least significant bits (LSBs) of the AID of the wireless communication terminal triggered by the trigger frame.

[0112] In addition, the user information field may indicate a resource unit (RU) allocated to a wireless communication terminal triggered by a trigger frame. The RU may indicate that multiple subcarriers that can be used for uplink and downlink transmissions can be grouped according to the size of the frequency band. In this case, at least one of OFDM, OFDMA, and MU-MIMO may be used in uplink and downlink transmissions. In addition, grouping may be referred to as subchannelization. In a specific embodiment, the RU allocation subfield may indicate an RU allocated to a wireless communication terminal indicated by the AID12 subfield.

[0113] The base station wireless communication terminal can use a trigger frame to trigger uplink transmission of any wireless communication terminal. Specifically, the base station wireless communication terminal can trigger random access to a specified RU. In this case, the base station wireless communication terminal can set the user information field of the trigger frame to indicate a predetermined value instead of the AID of a specific wireless communication terminal. In a specific embodiment, the base station wireless communication terminal can set the AID12 subfield of the user information field of the trigger frame to a predetermined value. In addition, when the user information field of the trigger frame indicates a predetermined value instead of the AID of a specific wireless communication terminal, the wireless communication terminal receiving the trigger frame is able to randomly access the RU indicated by the corresponding user information field. In a specific embodiment, when the AID12 subfield of the user information field of the trigger frame received by the wireless communication terminal indicates a predetermined value, the wireless communication terminal randomly accesses the RU indicated by the RU allocation subfield of the corresponding user information field. The predetermined value may be 0. In addition, the predetermined value may be 2045. Reference will be made to Fig. 9 The specific operation of a wireless communication terminal performing random access based on a trigger frame is described.

[0114] Fig. 9 A random access operation of a wireless communication terminal according to an embodiment of the present invention is shown.

[0115] The wireless communication terminal can perform an OFDMA random access operation by the following operations. The wireless communication terminal selects an arbitrary integer within the OFDMA contention window (OCW). Specifically, the wireless communication terminal can select a random integer from 0 to a value equal to or less than the OCW. In this case, the OCW can be equal to or greater than the OCW minimum value OCWmin, or can be equal to or less than the OCW maximum value OCWmax, which is a positive integer. The wireless communication terminal sets the selected number as an OFDMA random access backoff (OBO) counter. The wireless communication terminal can receive a trigger frame and decrement the OBO counter based on the RU in which the trigger frame indicates the random access. Specifically, the wireless communication terminal can receive a trigger frame and decrement the OBO counter by the number of RUs in which the trigger frame indicates the random access. When the OBO counter is 0 or the OBO counter reaches 0, the wireless communication terminal can randomly select any RU indicated for random access and attempt to transmit through the selected RU. In this case, the wireless communication terminal can determine whether the selected RU is idle, and when the selected RU is idle, the pending frame of the base station wireless communication terminal can be sent to the base station wireless communication terminal through the selected RU. In addition, when the wireless communication terminal determines that the corresponding RU is determined to be busy through physical carrier sensing or virtual carrier sensing, the wireless communication terminal can determine that the corresponding RU is busy. Physical carrier sensing may include clear channel assessment (CCA). In addition, physical carrier sensing may include energy detection (ED). When it is determined that the RU selected by the wireless communication terminal is busy, the wireless communication terminal may maintain the OBO counter at 0 without sending the pending frame to the base station wireless communication.

[0116] The wireless communication terminal may set OCWmin and OCWmax according to the OBO-related parameter value signaled by the base station wireless communication terminal associated with the wireless communication terminal. In addition, when the wireless communication terminal attempts random access for the first time, the wireless communication terminal receives the OBO-related parameter signaled by the base station wireless communication terminal, or the wireless communication terminal successfully transmits through random access, which may allow the wireless communication terminal to initialize the OBO process. In this case, the initialization of the OBO process may include at least one of the initialization of the OBO counter and the initialization of the OCW. In addition, when the wireless communication terminal initializes the OCW, the wireless communication terminal may set the OCW to OCWmin. When the transmission through the random access of the wireless communication terminal fails, the wireless communication terminal may update the value of the OCW to (2×OCW+1). In this case, the wireless communication terminal selects a random integer in the updated OCW and sets the random integer selected as the OBO counter. In addition, when the value of the OCW reaches OCWmax, the wireless communication terminal may maintain the OCW to OCWmax even if the transmission through the random access of the wireless communication terminal fails.

[0117] exist Fig. 9 In the embodiment of the present invention, the OBO counter of the first station STA1 is 5 and the OBO counter of the second station STA2 is 1. The AP sends a trigger frame, which triggers random access of the first RU RU1 and the second RU RU 2. Because the number of RUs allocated for random access is 2, the first station STA1 decrements the OBO counter by 2 and sets the OBO counter to 3, and the second station STA2 sets the OBO counter to 0. Because the OBO counter of the second station STA2 becomes 0, the second station STA2 randomly selects any one of the first RU RU 1 and the second RU RU 2 allocated for random access and attempts transmission. After SIFS from when the second station STA2 receives the trigger frame, the second station STA2 sends a TB PPDU to the AP through the randomly selected RU. The AP receives the TB PPDU from the second station STA2. After SIFS of receiving the TB PPDU from the AP, the AP sends an ACK of the frame sent by the second station to the second station.

[0118] The second station STA2 whose AP's transmission is successful sets the OCW to OCWmin and selects an arbitrary number within the set OCW. In this case, the second station STA2 selects 6 and sets 6 as the OBO counter. The AP sends a trigger frame that triggers random access to the first RU RU 1, the second RU RU 2, and the third RU RU 3. Because the number of RUs allocated for random access is 3, the first station STA1 decrements the OBO counter by 3 and sets it to 0, and the second station STA2 decrements the OBO counter by 3 and sets it to 3. Because the OBO counter of the first station STA1 becomes 0, the first station STA1 arbitrarily selects any one of the first RU RU1, the second RU RU 2, and the third RU RU 3, in which a trigger is allocated for random access, and attempts transmission. After SIFS when the trigger frame is received from the first station STA1, the first station STA1 sends a TBPPDU to the AP through the arbitrarily selected RU. The AP receives the TB PPDU from the first station STA1. After SIFS from the AP receiving the TB PPDU, the AP sends an ACK of the frame sent by the first station to the first station.

[0119] As described above, the wireless communication terminal may set OCWmin and OCWmax according to the OBO-related parameter values ​​signaled by the base station wireless communication terminal associated with the wireless communication terminal. Specifically, the wireless communication terminal may receive an element including the OBO-related parameter values ​​from the base station wireless communication terminal associated with the wireless communication terminal. In this case, the element may be referred to as a UL OFDMA-based random access (UORA) parameter set element. Fig.10 Describes the specific format of a UORA parameter set element.

[0120] Fig.10 A specific format of a UORA parameter set element according to an embodiment of the present invention is shown.

[0121] The UORA parameter set element may include an element ID field, a length field, an element ID extension field, and an OCW range field. The element ID field indicates an element identifier that identifies the UORA parameter set element. The length field indicates the length of the UORA element. The element ID extension field indicates an extension ID that is combined with the element ID to generate an extended ID of the UORA parameter set element. The OCW range field indicates information about the OCW range.

[0122] The OCW range field may include information about OCWmin and OCWmax. Specifically, the OCW range field may include an EOCWmin field, an EOCWmax field, and a reserved field. In this case, the wireless communication terminal may set OCWmin according to the value indicated by the EOCWmin field. In a specific embodiment, the wireless communication terminal may set OCWmin to 2. EOCWmin -1. In addition, the wireless communication terminal may set OCWmax according to the value indicated by the EOCWmax field. In a specific embodiment, the wireless communication terminal may set OCWmax to 2 EOCWmax -1.

[0123] The wireless communication terminal may set OCWmin and OCWmax based on the most recently received UORA parameter set element. In addition, the wireless communication terminal may set OCWmin and OCWmax based on the most recently received UORA parameter set element, regardless of the access category (AC) of the service to be sent. The base station wireless communication terminal may use a beacon frame to send the UORA parameter set element. In addition, the base station wireless communication terminal may use a probe response frame to send the UORA parameter set element.

[0124] The specific format of the UORA parameter set element can be Fig.10 The format is the same as in .

[0125] When there are multiple physical access points in a network, the time that a frame used for data transmission occupies the channel may be very short due to the management frames sent by multiple access points. Therefore, a base station wireless communication terminal can operate multiple BSSs in the network. Fig.11 Describe this.

[0126] Fig.11 A specific format of multiple BSSID elements according to an embodiment of the present invention is shown.

[0127] The base station wireless communication terminal may send a management frame to signal information about multiple BSSs. Specifically, the base station wireless communication terminal sends a management frame to signal information about each BSS corresponding to multiple BSS identifiers (BSSIDs) included in a multiple BSSID set. A multiple BSSID set is a collection of BSSIDs corresponding to each of multiple BSSs classified into a group. When the base station wireless communication terminal uses a multiple BSSID set, because the wireless communication terminal sends one management frame and sends information about multiple BSSs, the amount of time that a data frame can occupy a channel may be increased. In a specific embodiment, the wireless communication terminal may set a reference BSSID representing a multiple BSSID set to the BSS information indicated by the management frame, and insert information about the multiple BSSID set into the management frame. The information about the multiple BSSID set may include information about the maximum number of multiple BSSIDs included in the multiple BSSID set. In this case, the reference BSSID may be a BSSID used as a reference when identifying a BSSID included in the multiple BSSID set. Specifically, the information about the multiple BSSID set may be Fig.11 In this case, the information about the multiple BSSID set may include sub-elements.

[0128] The multiple BSSID elements may include an element ID field. The element ID field is an identifier indicating the multiple BSSID elements. In addition, the multiple BSSID elements may include a length field. The length field is a field indicating the length of the multiple BSSID elements. In addition, the multiple BSSID elements may indicate a maximum BSSID indicator field. In this case, the maximum BSSID indicator field may indicate information related to the maximum number of BSSIDs that the multiple BSSID set may include. Specifically, when the value indicated by the maximum BSSID indicator field is n, the maximum number of BSSIDs that the multiple BSSID set may include is 2. n In this case, the maximum number of BSSIDs is the number including the reference BSSID.

[0129] In addition, multiple BSSID elements may include optional sub-element fields. The optional sub-element may include information about the BSS indicated by the unsent BSSID. In addition to the reference BSSID, the unsent BSSID indicates the BSSID included in the multi-BSSID set. Specifically, the optional sub-element field may include an unsent BSSID profile, which is information about the BSS indicated by the unsent BSSID. The optional sub-element field may only include information about the BSS indicated by some unsent BSSIDs. In this case, the wireless communication terminal may obtain information about the BSS indicated by the remaining unsent BSSID based on a beacon frame or a probe response frame.

[0130] The information about the BSS indicated by the untransmitted BSSID may be an element to be included in the untransmitted BSSID capability element and the beacon frame body. Specifically, the element that may be included in the beacon frame body may be at least one of the SSID, the multi-BSSID index sub-element, and the FMD descriptor element. In addition, the same information as the BSS information indicated by the reference BSSID in the information about the BSS indicating the untransmitted BSSID may be omitted. Specifically, at least one of the timestamp and beacon interval fields indicated by the non-transmitted BSSID, DSSS parameter set, IBSS parameter set, country, channel switching announcement, extended channel switching announcement, broadband channel switching, transmit power envelope, support operation classification, IBSS DFS, ERP information, HT capability, HT operation, VHT capability, and VHT operation elements may be the same as the BSS indicated by the reference BSSID.

[0131] Additionally, the optional sub-elements field may include vendor-specific elements.

[0132] A wireless communication terminal that receives a management frame including information about a multi-BSSID set can obtain information about the multi-BSSID set from the management frame. In this case, the wireless communication terminal can obtain the BSSID included in the multi-BSSID set based on the information about the multi-BSSID set and the reference BSSID. Specifically, the wireless communication terminal can obtain the BSSID included in the multi-BSSID set by the following equation.

[0133] BSSID(i)=BSSID_A|BSSID_B

[0134] In this case, BSSID_A is a BSSID in which the (48-n) most significant bit (MSB) value is equal to the (48-n) MSB value of the reference BSSID, and the n least significant bit (LSB) value is 0. In addition, BSSID_B is a BSSID in which the (48-n) MSB value is 0, and the n LSB value is the sum of the n LSBs and i of the reference BSSID divided by 2. n The residual value (mod) when .

[0135] In addition, the base station wireless communication terminal can use the operation element to signal information about the multiple BSSID set. The operation element may include a MaxBSSID indicator field and a Tx BSSID indicator field. The MaxBSSID indicator field may indicate the same information as the maximum BSSID indicator field of the multiple BSSID elements. Therefore, in the same manner as the method of obtaining the BSSID of the BSS in which the management frame is sent using the MAX BSSID indicator field of the multiple BSSID element, the wireless communication terminal can obtain the BSSID of the BSS in which the management frame is sent by using the MaxBSSID indicator field. The Tx BSSID indicator field indicates whether the BSS to which the association frame including the operation element is sent corresponds to the unsent BSSID. Specifically, when the Tx BSSID indicator field is 1, the BSS in which the management frame including the operation element is sent corresponds to the sent BSSID. When the Tx BSSID indicator field is 0, the BSS in which the management frame including the operation element is sent corresponds to the unsent BSSID.

[0136] In addition, the wireless communication terminal may use the capability element of the management frame to signal information about capabilities associated with the multi-BSSID set. Specifically, the wireless communication terminal may use the capability element of the management frame to send to the Rx control frame field of the MultiBSS. When the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID, the Rx control frame field to the MultiBSS may indicate whether frames sent from the sent BSSID may be received. Specifically, the Rx control frame field to the MultiBSS may indicate whether control frames sent from the sent BSSID may be received when the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID.

[0137] When the BSS including the wireless communication terminal corresponds to a multi-BSSID set, the OFDMA random access operation of the wireless communication terminal is a problem. The reason is that the BSS included in the multi-BSSID set is a formally different BSS, but due to the purpose of using the multi-BSSID set, in the operation of a specific wireless communication terminal, the BSS included in the multi-BSSID set can be regarded as the same BSS (within the BSS). Moreover, the reason is that the trigger frame sent from the transmitted BSSID can trigger the uplink transmission of the wireless communication terminal included in the BSS corresponding to the unsent BSSID. Specifically, there are problems related to OBO-related parameter settings, OBO process initialization, OBO counter decrement operation and RU selection for random access in the operation of the wireless communication terminal.

[0138] When the BSS of the wireless communication terminal is included in the multi-BSSID set and the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID, the wireless communication terminal can set the OBO related parameters based on the UORA parameter set sent by the sent BSSID. When the BSS of the wireless communication terminal is included in the multi-BSSID set and the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID, the wireless communication terminal can update OCWmin and OCWmax according to the UORA parameter set sent by the sent BSSID. In this embodiment, the UORA parameter set may not be included in the unsent BSSID profile. In addition, the UORA parameter set may be commonly applied to at least one other BSS included in the multi-BSSID set. Therefore, when the BSS of the wireless communication terminal is included in the multi-BSSID set and the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID, the wireless communication terminal can set the OBO related parameters according to the UORA parameter set sent by the sent BSSID. In addition, when the BSS of the wireless communication terminal is included in the multi-BSSID set and the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID, the unsent BSSID profile sub-element corresponding to the BSS associated with the wireless communication terminal may not include the UORA parameter set element. In this way, when the unsent BSSID profile sub-element does not include the UORA parameter set element, the wireless communication terminal can set the OBO-related parameters according to the UORA parameter set sent by the sent BSSID.

[0139] When the base station wireless communication terminal sends a management frame in the BSS corresponding to the transmitted BSSID, the base station wireless communication terminal can use the UORA parameter set sent by the transmitted BSSID to signal OBO-related parameters for use by wireless communication terminals of multiple BSSs corresponding to the multi-BSSID set. In addition, when the base station wireless communication terminal sends a management frame in the BSS corresponding to the transmitted BSSID, the base station wireless communication terminal can use the untransmitted BSSID profile sub-element to signal the wireless communication terminal corresponding to the untransmitted BSSID to send OBO-related parameters separated from other BSSs in the multi-BSSID set. Through these embodiments, the base station wireless communication terminal can effectively signal OBO-related parameters to multiple wireless communication terminals included in the BSS corresponding to the multi-BSSID set.

[0140] As described above, when the wireless communication terminal uses a signal to transmit information about OBO-related parameters from the base station wireless communication terminal, the wireless communication terminal can initialize the OBO process. Therefore, if the BSS of the wireless communication terminal is included in the multi-BSSID set and the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID, when the wireless communication terminal receives the UORA parameter set sent by the sent BSSID, the wireless communication terminal can initialize the OBO process. If the BSS of the wireless communication terminal is included in the multi-BSSID set and the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID, when the wireless communication terminal receives the UORA parameter set sent by the sent BSSID, the wireless communication terminal can initiate the OBO process. In addition, when the BSS of the wireless communication terminal is included in the multi-BSSID set and the wireless communication terminal is associated with the BSS corresponding to the unsent BSSID, the unsent BSSID profile sub-element corresponding to the BSS associated with the wireless communication terminal may not include the UORA parameter set element. In this case, the wireless communication terminal can initiate the OBO process. In a specific embodiment, when the wireless communication terminal initiates the OBO process, the wireless communication terminal can set the OCW to OCWmin and randomly select the OBO counter within the OCW.

[0141] If the transmitter address TA of the trigger frame is the BSSID of the associated BSS, the wireless communication terminal can decrement the OBO counter based on the RU indicated by the trigger frame. Therefore, even when the BSS of the wireless communication terminal is included in a multi-BSSID set, when the transmitter address TA of the trigger frame is the BSSID of the BSS associated with the wireless communication terminal, the wireless communication terminal can decrement the OBO counter based on the RU indicated by the trigger frame. Specifically, when the BSS of the wireless communication terminal is included in a multi-BSSID set and the transmitter address of the trigger frame is a sent BSSID, the wireless communication terminal associated with the BSS with an unsent BSSID may not be decremented based on the RU indicated by the corresponding trigger frame. In addition, when the BSS of the wireless communication terminal is included in a multi-BSSID set and the transmitter address of the trigger frame is an unsent BSSID, the wireless communication terminal associated with the BSS with a sent BSSID may not be decremented based on the RU indicated by the corresponding trigger frame.

[0142] In another specific embodiment, when the transmitter address of the trigger frame is the transmitted BSSID, the wireless communication terminal associated with the BSS with the untransmitted BSSID may allow the OBO counter to be decremented based on the trigger frame. However, in this embodiment, the fairness of the wireless communication terminal associated with the BSS with the transmitted BSSID may be a problem. In addition, when the receiver address of the trigger frame is a BSSID included in a multi-BSSID set, the wireless communication terminal associated with the BSS included in the multi-BSSID set may allow the OBO counter to be decremented based on the trigger frame. In this embodiment, because the wireless communication terminal associated with the BSS corresponding to the transmitted BSSID can decrement the OBO counter based on the trigger frame that cannot trigger the wireless communication terminal, the fairness of the random access operation of the wireless communication terminal not associated with the BSS corresponding to the multi-BSSID set may be a problem. Moreover, even if the transmitter address of the trigger frame is the transmitted BSSID and the trigger frame triggers the transmission to the wireless communication terminal associated with the untransmitted BSSID, the wireless communication terminal associated with the BSSID may be allowed to decrement the OBO counter based on the trigger frame. In order to confirm whether the sent trigger frame addressed to the sent BSSID triggers transmission to the wireless communication terminal associated with the unsent BSSID, the wireless communication terminal may be required to decode the user information field. Therefore, this embodiment may increase the complexity of the random access operation of the wireless communication terminal.

[0143] Reference Fig.12 The specific operations of the wireless communication terminal related to OBO related parameter settings, OBO process initialization, OBO counter decrement operation and RU selection for random access are described in detail.

[0144] Figures 12 to 13 A random access operation of a wireless communication terminal associated with a multiple BSSID set according to an embodiment of the present invention is shown.

[0145] exist Fig.12 In an embodiment, the first station STA1 is associated with a BSS corresponding to a transmitted BSSID of a multi-BSSID set. The second station STA2 is associated with a BSS corresponding to a non-transmitted BSSID of a multi-BSSID set. The first station STA1 and the second station STA2 receive a beacon frame sent from the transmitted BSSID. In this case, the first station STA1 and the second station STA2 update OCWmin and OCWmax according to the UORA parameter set element included in the beacon frame. In a specific embodiment, because the UORA parameter set of the beacon frame is announced by the transmitted BSSID and is not included in the non-transmitted BSSID profile sub-element, the second station STA2 can update OCWmin and OCWmax according to the UORA parameter set element.

[0146] In addition, since the first station STA1 and the second station STA2 receive information about OBO related parameters from the base station wireless communication terminal, the first station STA1 and the second station STA2 initialize the OBO process. Specifically, the first station STA1 and the second station STA2 randomly select the OBO counter within the OCW. The first station STA1 selects 3, and the second station STA2 selects 5.

[0147] The first station STA1 and the second station STA2 receive a trigger frame with the transmitted BSSID as the transmitter address TA. In this case, the trigger frame indicates that two RUs are allocated for random access. Fig.12 In the embodiment of , it is assumed that the wireless communication terminal associated with the BSS included in the multi-BSSID set can decrement the OBO counter based on the trigger frame having the BSSID included in the multiple BSSIDs set as the transmitter address. Therefore, the first station STA1 sets the OBO counter to 1 by decrementing the OBO counter by 2 according to the trigger frame, and the second station STA2 associated with the BSS corresponding to the untransmitted BSSID decrements the OBO counter by 2 and sets the OBO counter to 3 according to the trigger frame.

[0148] The first station STA1 and the second station STA2 receive a trigger frame with an untransmitted BSSID as a transmitter address TA. In this case, the trigger frame indicates that two RUs are allocated for random access. The first station STA1 decrements the OBO counter by 2 according to the trigger frame to set the OBO counter to 0 and randomly selects one of the two RUs allocated for random access indicated by the trigger frame and attempts to perform transmission. The second station STA2 associated with the BSS corresponding to the untransmitted BSSID decrements the OBO counter by 2 according to the trigger frame to set the OBO counter to 1.

[0149] If the first station STA1 and the second station STA2 receive a beacon frame that does not include the UORA parameter set element, the first station STA1 and the second station STA2 maintain the existing OBO process. The first station STA1 and the second station STA2 receive a beacon frame sent from the transmitted BSSID. In this case, the beacon frame includes the UORA parameter set element. Therefore, the first station STA1 and the second station STA2 update OCWmin and OCWmax according to the UORA parameter set element included in the beacon frame, and initialize the OBO process.

[0150] refer to Fig.12 The described OBO counter decrement operation can complicate the random access operation of the wireless communication terminal as described above, and may cause fairness issues with other wireless communication terminals. Fig.13As shown in, even when the BSS of the wireless communication terminal is included in a multi-BSSID set, when the transmitter address TA of the trigger frame is the BSSID of the BSS associated with the wireless communication terminal, the wireless communication terminal can also decrement the OBO counter based on the RU indicated by the trigger frame.

[0151] exist Fig.13 In the embodiment of Fig.12 The same operation and situation as described in the embodiment. The first station STA1 and the second station STA2 receive a trigger frame with a transmitted BSSID as a transmitter address TA. In this case, the trigger frame indicates that two RUs are allocated for random access. The first station STA1 associated with the BSS corresponding to the transmitted BSSID decrements the OBO counter by 2 according to the trigger frame to set the OBO counter to 1. Because the second station STA2 is associated with the BSS corresponding to the untransmitted BSSID, the second station STA2 maintains the OBO counter to 5.

[0152] In addition, the first station STA1 and the second station STA2 receive a trigger frame with an untransmitted BSSID as a transmitter address TA. In this case, the trigger frame indicates that two RUs are allocated for random access. Because the first station STA1 is associated with the BSS corresponding to the transmitted BSSID, the first station STA1 maintains the OBO counter to 1. The second station STA2 associated with the BSS corresponding to the untransmitted BSSID decrements the OBO counter by 2 to set the OBO counter to 3.

[0153] Even if the trigger frame triggers random access, when the capability of the wireless communication terminal does not support the uplink transmission condition indicated by the trigger frame, the wireless communication terminal cannot perform random access even if the OBO counter reaches 0. For example, when the wireless communication terminal does not support the transmission of the frequency bandwidth of the RU (indicated as the RU allocated for random access), the corresponding wireless communication terminal cannot perform random access to the corresponding RU. Therefore, a random access operation that takes into account the capability of the wireless communication terminal is required.

[0154] When the wireless communication terminal receives a trigger frame, the wireless communication terminal can decrement the OBO counter according to the capabilities of the wireless communication terminal. Specifically, when the wireless communication terminal receives a trigger frame, the wireless communication terminal can decrement the OBO counter based on the RUs allocated for random access and the capabilities of the wireless communication terminal. In a specific embodiment, the wireless communication terminal can decrement the OBO counter by the number of RUs among the randomly allocated RUs through which the wireless communication terminal can send TB PPDUs according to the capabilities of the wireless communication terminal. As described above, the RUs allocated for random access can be indicated by a trigger frame. In addition, the wireless communication terminal can determine whether the TBPPDU can be sent through the RU based on the transmission conditions indicated by the trigger frame.

[0155] In addition, when the OBO counter reaches 0, the wireless communication terminal may select an RU according to the capability of the wireless communication terminal. In a specific embodiment, when the OBO counter reaches 0, the wireless communication terminal may randomly select any one of the RUs allocated for random access and in which the wireless communication terminal can send a TB PPDU according to the capability of the wireless communication terminal.

[0156] When the OBO counter reaches 0, the wireless communication terminal may postpone random access and maintain the OBO counter. Specifically, when there is no data corresponding to the response length indicated by the trigger frame buffered in the wireless communication terminal, the wireless communication terminal may postpone random access and maintain the OBO counter to 0. In this case, the wireless communication terminal may perform random access in response to the next trigger frame that triggers random access. In addition, if there is no RU through which the wireless communication terminal can send a TB PPDU according to the capabilities of the wireless communication terminal among the RUs allocated for random access, the wireless communication terminal may maintain the OBO counter to 0. In this case, the wireless communication terminal may perform random access in response to the next trigger frame that triggers random access.

[0157] In addition, the capabilities of the wireless communication terminal may include capabilities of the wireless communication terminal, which are related to at least one of a bandwidth supported for transmission, a modulation and coding scheme (MCS), a dual carrier modulation (DCM), the number of spatial streams, a length of a guard interval (GI), a long training field (LTF) type, a space-time block coding (STBC), a transmission power, and a length of a padding field. The length of the padding field may indicate the length of the padding field included in the TB PPDU. Reference will be made to Figures 14 to 21 Describe the specific operations of the wireless communication terminal.

[0158] Fig.14 Shown are the types of RUs and subcarrier indexes that can be used when sending a PPDU with a bandwidth of 20 MHz according to an embodiment of the present invention. Fig.15Shown are the types of RUs and subcarrier indexes that can be used when a PPDU with a bandwidth of 40 MHz is transmitted according to an embodiment of the present invention. Fig.16 It shows the types of RU and subcarrier index that can be used when sending a PPDU with a bandwidth of 80 MHz according to an embodiment of the present invention.

[0159] As described above, the RU may indicate that a plurality of subcarriers available for uplink and downlink transmission may be grouped according to the size of a frequency band.

[0160] According to an embodiment of the present invention, a wireless communication terminal can use at least one of an RU using 26 subcarriers (26-tone RU), an RU using 52 subcarriers (52-tone RU), an RU using 106 subcarriers (106-tone RU), an RU using 242 subcarriers (242-tone RU), an RU using 484 subcarriers (484-tone RU), an RU using 996 subcarriers (996-tone RU), and an RU using 1992 subcarriers (2*996-tone RU) to perform uplink transmission or downlink transmission. Specifically, the wireless communication terminal can use the designated RU to send a HE MU PPDU or a HE-triggered PPDU through OFDMA. In this case, when the frequency bandwidth of the PPDU is any one of 20MHz, 40MHz, 80MHz, 160MHz, and 80+80MHz, the wireless communication terminal can use any one of the 26-tone RU, 52-tone RU, 106-tone RU, and 242-tone RU to send the PPDU. In addition, when the frequency bandwidth of the PPDU is any one of 40MHz, 80MHz, 160MHz and 80+80MHz, the wireless communication terminal can use 484 tone RU to send the PPDU. In addition, when the frequency bandwidth of the PPDU is any one of 80MHz, 160MHz and 80+80MHz, the wireless communication terminal can use 996 tone RU. In addition, when the frequency bandwidth of the PPDU is any one of 160MHz and 80+80MHz, the wireless communication terminal can use 2*996 tone RU to send the PPDU.

[0161] In addition, the wireless communication terminal can use a designated RU to send a HE single user (SU) PPDU. In this case, if the frequency bandwidth of the HE SU PPDU is 20 MHz, the wireless communication terminal can use a 242-tone RU to send the HE SU PPDU. In addition, if the frequency bandwidth of the HE SU PPDU is 40 MHz, the wireless communication terminal can use a 484-tone RU to send the HE SU PPDU. In addition, if the frequency bandwidth of the HE SU PPDU is 80 MHz, the wireless communication terminal can use a 996-tone RU to send the HE SU PPDU. In addition, if the frequency bandwidth of the HE SU PPDU is 160 MHz or 80+80 MHz, the wireless communication terminal can use a 2*996-tone RU to send the HE SU PPDU.

[0162] The 26-tone RU may include 24 subcarriers for sending data and 2 subcarriers for sending pilot signals. The specific location of the 26-tone RU may be related to Fig.14 , Fig.15 as well as Fig.16 When the frequency bandwidth of the PPDU sent by the wireless communication terminal is a 160 MHz or 80+80 MHz PPDU, the 26-tone RU sent through each 80 MHz frequency band can be the same as shown in FIG. Fig.15 The 52-tone RU may include 48 subcarriers for transmitting data and 4 subcarriers for transmitting pilot signals. The specific location of the 52-tone RU may be the same as that shown in FIG. Fig.14 , Fig.15 as well as Fig.16 When the frequency bandwidth of the PPDU sent by the wireless communication terminal is a 160 MHz or 80+80 MHz PPDU, the 52-tone RU sent through each 80 MHz frequency band can be the same as Fig.15 Same as shown in .

[0163] The 106-tone RU may include 102 subcarriers for transmitting data and 4 subcarriers for transmitting pilot signals. The specific location of the 106-tone RU may be related to Fig.14 , Fig.15 as well as Fig.16 When the frequency bandwidth of the PPDU sent by the wireless communication terminal uses a 160 MHz or 80+80 MHz PPDU, the 106-tone RU sent through each 80 MHz frequency band can be the same as Fig.15 The 242-tone RU may include 234 subcarriers for transmitting data and 8 subcarriers for transmitting pilot signals. The specific location of the 242-tone RU may be the same as that shown in FIG. Fig.14 , Fig.15 and Fig.16When the frequency bandwidth of the PPDU sent by the wireless communication terminal is a 160 MHz or 80+80 MHz PPDU, the 242-tone RU sent through each 80 MHz frequency band can be the same as Fig.15 The same as shown in .

[0164] The 484-tone RU may include 468 subcarriers for transmitting data and 16 subcarriers for transmitting pilot signals. The specific location of the 484-tone RU may be related to Fig.15 and Fig.16 When the frequency bandwidth of the PPDU sent by the wireless communication terminal is 160MHz or 80+80MHz PPDU, the 484-tone RU sent through each 80MHz frequency band can be the same as Fig.15 The 996-tone RU may include 980 subcarriers for transmitting data and 16 subcarriers for transmitting pilot signals. The specific location of the 996-tone RU may be the same as that shown in FIG. Fig.15 When the frequency bandwidth of the PPDU sent by the wireless communication terminal is 160MHz or 80+80MHz PPDU, the 996-tone RU sent through each 80MHz frequency band can be the same as Fig.15 The same as shown. When the wireless communication terminal sends a PPDU with a bandwidth of 160MHz or 80+80MHz, the subcarriers contained in the 996-tone RU are located at [-1012:-515, -509:-12] and [12:509,515:1012]. In this case, [x:y] represents subcarrier indexes x to y. Therefore, even when using a 2*996-tone RU, the wireless communication terminal uses subcarriers located at subcarrier indices of [-1012:-515, -509:-12] and [12:509,515:1012].

[0165] If the wireless communication terminal sends a HE MU PPDU or a HE triggered PPDU with a frequency bandwidth of 20MHz and the PPDU includes two or more RUs, the wireless communication terminal can send seven direct current (DC) subcarriers at [-3:3]. When the wireless communication terminal sends a HE SU PPDU with a frequency bandwidth of 20MHz using a 242-tone RU, the wireless communication terminal can send three DC subcarriers at [-1:1]. When the wireless communication terminal sends a HE SU PPDU with a frequency bandwidth of 40MHz using a 484-tone RU, the wireless communication terminal can send five DC subcarriers at [-2:2]. If the wireless communication terminal sends a HE MU PPDU or a HE triggered PPDU with a frequency bandwidth of 80MHz and the PPDU includes two or more RUs, the wireless communication terminal can send seven DC subcarriers at [-3:3]. When the wireless communication terminal sends a HE SU PPDU with a frequency bandwidth of 80MHz using a 996-tone RU, the wireless communication terminal can send five DC subcarriers at [-2:2]. When the wireless communication terminal transmits a PPDU having a bandwidth of 160 MHz or 80+80 MHz, the wireless communication terminal can transmit the DC subcarrier to the same position as the case of transmitting a HE SU PPDU having a frequency bandwidth of 80 using a 996-tone RU.

[0166] When the wireless communication terminal sends a PPDU with a 20MHz frequency bandwidth, the wireless communication terminal can send 11 protection subcarriers to [-128:-123] and [123:127]. When the wireless communication terminal sends a PPDU with a 40MHz frequency bandwidth, the wireless communication terminal can send 23 protection subcarriers to [-256:-245] and [245:255]. When the wireless communication terminal sends a PPDU with an 80MHz frequency bandwidth, the wireless communication terminal is able to send 23 protection subcarriers to [-512:-501] and [501:511]. When the wireless communication terminal sends a PPDU with a 160MHz or 80+80MHz frequency bandwidth, the wireless communication terminal can send the protection subcarriers used to send the PPDU with an 80MHz frequency bandwidth to both ends.

[0167] Fig.17 The coding value of the RU in the RU allocation subfield of the trigger frame is shown according to an embodiment of the present invention.

[0168] The RU allocation subfield indicates the RU to be used for transmission by the wireless communication terminal triggered by the trigger frame. The RU allocation subfield can be an 8-bit field. In this case, one bit of the RU allocation subfield, for example, B12, can indicate whether the RU indicated by the RU allocation subfield is in the primary 80 MHz channel or the non-primary 80 MHz channel. The primary channel represents a frequency band that serves as a basis for frequency band extension. Moreover, the primary channel may refer to a continuous frequency band, which includes a frequency band with a 20 MHz frequency bandwidth, which is the basis for frequency band extension. In addition, when the RU has a frequency bandwidth of 80 MHz or less, 7 bits of the RU allocation subfield, for example, B19-B13, indicate which RU is indicated in 80 MHz. In addition, when the RU has a frequency bandwidth equal to or greater than 80 MHz, 7 bits of the RU allocation subfield, for example, B19-B13, indicate which RU is indicated in a frequency bandwidth equal to or greater than 80 MHz. The specific value of the RU allocation field may be different from Fig.17 The same as in.

[0169] Specifically, in the case where the PPDU has a frequency bandwidth of 20 MHz, 40 MHz, or 80 MHz, B12 may be set to 0. Also, in the case of a 2*996 tone RU, B12 may be set to 1. In addition, B19-B13 may also be set as follows.

[0170] -When the wireless communication terminal sends a PPDU with a frequency bandwidth of 20 MHz, the wireless communication terminal may specify in B19-B13 according to the ascending order Fig.14 RU Index of B19-B13. When the value of B19-B13 is 0000000, the RU Allocation Subfield may indicate 26-tone RU 1. When the value of B19-B13 is 0001000, the RU Allocation Subfield may indicate 26-tone RU 9. The values ​​of B19-B13 may not be used 0001001 to 0100100. When the value of B19-B13 is 0100101, the RU Allocation Subfield may indicate 52-tone RU 1. When the value of B19-B13 is 0101000, the RU Allocation Subfield may indicate 52-tone RU 4. The values ​​of B19-B13 may not be used 0101001 to 0110100. When the value of B19-B13 is 0110101, the RU Allocation Subfield may indicate 106-tone RU1. When the value of B19-B13 is 0110110, the RU Allocation subfield may indicate 106-tone RU 2. The value of B19-B13 may not be used 0110111 to 0111100. When the value of B19-B13 is 0111101, the RU Allocation subfield may indicate 242-tone RU1. The value of B19-B13 may not be used 0111110 to 1000000.

[0171] -When the wireless communication terminal sends a PPDU with a frequency bandwidth of 40 MHz, the wireless communication terminal may specify in B19-B13 according to ascending order Fig.15 RU index of. When the value of B19-B13 is 0000000, the RU Allocation subfield may indicate 26-tone RU1. When the value of B19-B13 is 0010001, the RU Allocation subfield may indicate 26-tone RU18. The value of B19-B13 may not be used 0010010 to 0100100. When the value of B19-B13 is 0100101, the RU Allocation subfield may indicate 52-tone RU1. When the value of B19-B13 is 0101100, the RU Allocation subfield may indicate 52-tone RU 8. The value of B19-B13 may not be used 0101101 to 0110100. The value of B19-B13 may be specified as 106-tone, 242-tone, and 484-tone RU according to rules such as 26-tone RU and 52-tone RU.

[0172] -When the wireless communication terminal sends a PPDU with frequency bandwidths of 80 MHz, 160 MHz, and 80+80 MHz, the wireless communication terminal may specify in B19-B13 according to ascending order Fig.12 RU index. When the value of B19-B13 is 0000000, the RU Allocation subfield may indicate 26-tone RU 1. When the value of B19-B13 is 0100100, the RU Allocation subfield may indicate 26-tone RU 37. When the value of B19-B13 is 0100101, the RU Allocation subfield may indicate 52-tone RU 1. If the value of B19-B13 is 0110100, the value of the RU Allocation subfield may indicate 52-tone RU 16. The value of B19-B13 may be designated for 106-tone, 242-tone, 484-tone, and 996-tone RU according to rules such as 26-tone RU and 52-tone RU. When the wireless communication terminal sends a 160MHz or 80+80MHz PPDU and the value of B19-B13 is 1000100, the RU Allocation subfield may indicate 2*996-tone RU.

[0173] The wireless communication terminal is capable of supporting the transmission and reception of PPDUs whose frequency bandwidth is equal to or narrower than a specific size. For example, the wireless communication terminal may only support the transmission and reception of PPDUs with a bandwidth of 20MHz. In addition, the wireless communication terminal may support the transmission and reception of PPDUs with a frequency bandwidth of 80MHz or less. In this way, when the wireless communication terminal only supports the transmission and reception of PPDUs with a frequency bandwidth equal to or narrower than a specific size, the wireless communication terminal may decrement the OBO counter based on the number of RUs included in the frequency bandwidth equal to or narrower than a specific size among the RUs allocated for random access. In this case, the RUs allocated for random access may be indicated by a trigger frame. In addition, the wireless communication terminal decrements the OBO counter when receiving the trigger frame. Specifically, when the wireless communication terminal only supports the transmission and reception of PPDUs with a frequency bandwidth equal to or narrower than a specific size, the wireless communication terminal may reduce the OBO counter based on the number of RUs included in the main channel with a frequency bandwidth equal to or narrower than a specific size among the RUs allocated for random access. The wireless communication terminal may not support non-main channels because it is difficult to switch channels within a specific time. In this case, the non-main channel may refer to a channel other than the main channel. For example, when the wireless communication terminal supports only transmission and reception of PPDUs having a frequency bandwidth equal to or less than 20 MHz, the wireless communication terminal may decrement the OBO counter based on the number of RUs in which the B19-B13 values ​​of the RU allocation subfield are 0000000 to 0001000 or 0100101 to 0101000 or 0110101 to 0110110 or 0111101 among the RUs allocated for random access. In another specific embodiment, when the wireless communication terminal supports only transmission and reception of PPDUs having a frequency bandwidth equal to or less than a specific size, the wireless communication terminal may decrement the OBO counter based on the number of RUs included in a frequency bandwidth equal to or narrower than a specific size among the RUs allocated for random access, regardless of whether the RUs are included in a primary channel. For example, when the wireless communication terminal only supports the transmission and reception of PPDUs having a frequency bandwidth equal to or less than 20 MHz or less, the wireless communication terminal may decrement the OBO counter based on the number of RUs among the RUs allocated for random access in which the B19-B13 values ​​of the RU allocation subfields are less than or equal to 1000000.

[0174] In addition, when the OBO counter reaches 0 and the wireless communication terminal only supports the transmission and reception of PPDUs with a frequency bandwidth equal to or less than a specific size, the wireless communication terminal can randomly select any RU allocated for random access and included in a frequency bandwidth equal to or less than a specific size. In this case, the wireless communication terminal can attempt to transmit through the selected RU. The RU allocated for random access can be indicated by a trigger frame as described above. When there is no frequency bandwidth equal to or narrower than a specific size in the RU allocated for random access, the wireless communication terminal can maintain the OBO counter while not attempting to transmit. In this case, the wireless communication terminal can attempt random access in response to the next trigger frame sent. In this embodiment, when the wireless communication terminal decrements the OBO counter, the wireless communication terminal may not consider the capabilities of the wireless communication terminal. Specifically, when the wireless communication terminal decrements the OBO counter regardless of whether the RU is included in a frequency bandwidth of a specific size or less, when the OBO counter reaches 0, the wireless communication terminal can randomly select any one of the RUs allocated for random access and included in a frequency bandwidth of a specific size or less.

[0175] In addition, in a specific embodiment, the wireless communication terminal may randomly select any one of the RUs allocated for random access and the RUs included in the main channel whose bandwidth is equal to or narrower than a specific size. The wireless communication terminal may not support non-main channels because it is difficult to switch channels within a specific time. For example, when the wireless communication terminal only supports the transmission and reception of PPDUs with a frequency bandwidth equal to or less than 20MHz, the wireless communication terminal can arbitrarily select any one of the RUs allocated for random access and the RUs in which the B19-B13 values ​​of the RU allocation subfield corresponding to the corresponding RU are 0000000 to 0001000 or 0100101 to 0101000 or 0110101 to 0110110 or 0111101. In another specific embodiment, when the wireless communication terminal only supports the transmission and reception of PPDUs whose frequency bandwidth is equal to or narrower than a specific size, the wireless communication terminal may randomly select any one of the RUs allocated for random access, regardless of whether the RU is included in the main channel and is included in a frequency bandwidth of a specific size or less. For example, when the wireless communication terminal only supports PPDU transmission and reception with a frequency bandwidth equal to or less than 20 MHz, the wireless communication terminal can arbitrarily select any one of the RUs allocated for random access in which the value of B19-B13 of the RU allocation subfield corresponding to the corresponding RU is 1000000 or less.

[0176] Figures 18 to 19 An operation in which a wireless communication terminal supporting only a PPDU having a bandwidth of 20 MHz performs random access according to an embodiment of the present invention is illustrated.

[0177] exist Figures 18 to 21 In an embodiment of the present invention, the wireless communication terminal decrements the OBO counter based on the frequency bandwidth supported by the wireless communication terminal. Fig.18 and Fig. 20 In an embodiment, when the RU allocated for random access is included in a primary channel having a frequency bandwidth equal to or narrower than a specific size, the wireless communication terminal decrements the OBO counter based on the corresponding RU.

[0178] exist Fig.18 In the embodiment, the first station STA1 only supports a frequency band equal to or narrower than 20 MHz. The second station STA2 supports a frequency band equal to or wider than 20 MHz. The first station STA1 and the second station STA2 receive a beacon frame from the first AP AP1. The first station STA1 and the second station STA2 obtain the UORA parameter set element from the beacon frame and initialize the OBO process. Specifically, the first station STA1 sets OCWmin and OCWmax according to the UORA parameter set element, and initializes the OCW. The first station STA1 randomly selects 10 in the OCW and sets the OBO counter to 10. In addition, the second station STA2 sets OCWmin and OCWmax according to the UORA parameter set element, and initializes the OCW. The second station STA2 arbitrarily selects 12 in the OCW and sets the OBO counter to 12.

[0179] The first station STA1 and the second station STA2 receive a trigger frame from the first AP AP1. In this case, the trigger frame indicates two RUs, where the RUs are allocated for random access. One RU is included in a main channel with a frequency bandwidth of 20 MHz, and the other RU is not included in a main channel with a frequency bandwidth of 20 MHz. Because the first station STA1 only supports a frequency bandwidth equal to or less than 20 MHz, the first station STA1 decrements the OBO counter by 1 and sets the OBO counter to 9. Because the second station STA2 also supports a frequency bandwidth equal to or wider than 20 MHz, the second station STA2 decrements the OBO counter by 2 and sets the OBO counter to 10.

[0180] exist Fig.19 In the embodiment, the first station STA1 only supports a frequency band equal to or less than 20 MHz, and the second station STA2 supports a frequency band equal to or greater than 20 MHz, such as Fig.18 The description of the operation of the first station STA1 and the second station STA2 will be omitted. Fig.18 The same as those in the embodiment.

[0181] The first station STA1 and the second station STA2 receive a trigger frame from the first AP AP1. In this case, the trigger frame indicates two RUs, and the RUs are allocated for random access. The frequency bandwidth of one RU is equal to or less than 20 MHz, and the frequency bandwidth of the other RU is greater than 20 MHz. Because the first station STA1 only supports a frequency bandwidth equal to or less than 20 MHz, the first station STA1 decrements the OBO counter by 1 and sets the OBO counter to 9. Because the second station STA2 also supports a frequency bandwidth equal to or greater than 20 MHz, the second station STA2 decrements the OBO counter by 2 and sets the OBO counter to 10.

[0182] Figures 20 to 21 It is shown that a wireless communication terminal that only supports PPDU with a bandwidth equal to or less than 80 MHz performs a random access operation according to an embodiment of the present invention.

[0183] exist Fig. 20 In the embodiment of the present invention, the first station STA1 only supports a frequency band equal to or less than 80 MHz, and the second station STA2 supports a frequency band equal to or greater than 80 MHz (160 MHz, 80+80 MHz). Figure 18 to Figure 19 Description of operations of the first station STA1 and the second station STA2 that are the same as those in the embodiment will be omitted.

[0184] The first station STA1 and the second station STA2 receive a trigger frame from the first AP AP1. In this case, the trigger frame indicates two RUs, and the RUs are allocated for random access. One RU is included in the main channel with a frequency bandwidth of 80 MHz, and the other RU is not included in the main channel with a frequency bandwidth of 80 MHz. Because the first station STA1 only supports a frequency bandwidth equal to or less than 80 MHz, the first station STA1 decrements the OBO counter by 1 and sets the OBO counter to 9. Because the second station STA2 also supports a frequency bandwidth equal to or wider than 80 MHz, the second station STA2 decrements the OBO counter by 2 and sets the OBO counter to 10.

[0185] exist Fig.21 In the embodiment, the first station STA1 only supports a frequency band of 80 MHz or less, and the second station STA2 supports a frequency band equal to or greater than 80 MHz (160 MHz, 80+80 MHz), such as Fig. 20 As in the embodiment of Figures 18 to 20 The description of the operations of the first station STA1 and the second station STA2 in the embodiments are the same as those in the embodiments.

[0186] The first station STA1 and the second station STA2 receive a trigger frame from the first AP AP1. In this case, the trigger frame indicates two RUs, and the RUs are allocated for random access. The frequency bandwidth of one RU is equal to or less than 80 MHz, and the frequency bandwidth of the other RU is greater than 80 MHz. Because the first station STA1 only supports a frequency bandwidth equal to or less than 80 MHz, the first station STA1 decrements the OBO counter by 1 and sets the OBO counter to 9. Because the second station STA2 also supports a frequency bandwidth equal to or greater than 20 MHz, the second station STA2 decrements the OBO counter by 2 and sets the OBO counter to 10.

[0187] In the above-mentioned random access operation of the wireless communication terminal, the wireless communication terminal receives information about OBO-related parameters from the base station wireless communication terminal associated with the wireless communication terminal, and sets the OBO-related parameters according to the received information. Specifically, a UORA parameter set element is received from the base station wireless communication terminal associated with the wireless communication terminal, and the OBO-related parameters are set based on the UORA parameter set element. A wireless communication terminal that is not associated with the base station wireless communication terminal is able to perform random access based on a trigger frame sent by the base station wireless communication terminal. In this case, a method of setting OBO-related parameters and a method of initializing the OBO process by a non-associated wireless communication terminal become issues. This will refer to Figure 22 to Figure 25 If there is no other description in this specification, a non-associated wireless communication terminal may refer to a wireless communication terminal that is not associated with any base station wireless communication terminal.

[0188] Fig. 22 A random access operation of a non-associated wireless communication terminal according to an embodiment of the present invention is shown.

[0189] When the wireless communication terminal receives a trigger frame that triggers random access of the wireless communication terminal from a base station wireless communication terminal that is not associated with the wireless communication terminal, the wireless communication terminal can start the OBO process based on information about OBO-related parameters sent by the corresponding base station wireless communication terminal. Specifically, the wireless communication terminal can receive a UORA parameter set element from a wireless communication terminal that is not associated with the base station wireless communication terminal. In this case, when the wireless communication terminal receives a trigger frame that triggers random access of the wireless communication terminal from the corresponding base station wireless communication terminal, the wireless communication terminal can set OCWmin and OCWmax according to the UORA parameter set element and start the OBO process.

[0190] When the wireless communication terminal receives a trigger frame that triggers random access of the wireless communication terminal from a wireless communication terminal that is different from the base station wireless communication terminal that sends the UORA parameter set element, the wireless communication terminal may not perform the OBO related process according to the received UORA parameter set element. Specifically, when the wireless communication terminal receives a trigger frame that triggers random access of the wireless communication terminal from a wireless communication terminal that is different from the base station wireless communication terminal that sends the UORA parameter set element, the wireless communication terminal may not decrement the OBO counter based on the trigger frame. To this end, the wireless communication terminal may compare the identifier of the base station wireless communication terminal that sends the UORA parameter set element with the identifier of the base station wireless communication terminal that sends the trigger frame. In this case, the identifier of the base station wireless communication terminal may be a MAC address or a BSSID. In the above embodiment, the trigger frame for triggering random access may be a trigger frame for triggering random access of non-associated wireless communication terminals.

[0191] In addition, when the wireless communication terminal receives a new UORA parameter set element from a wireless communication terminal different from the base station wireless communication terminal that sends the UORA parameter set element, the wireless communication terminal may not initialize the OBO process based on the newly received UORA parameter set element. In this case, the initialization of the OBO process includes at least one of the OBO counter initialization and the OCW initialization. In addition, when the wireless communication terminal receives a new UORA parameter set element from a wireless communication terminal different from the base station wireless communication terminal that sends the UORA parameter set element, the wireless communication terminal may not set the OBO-related parameters based on the newly received UORA parameter set element. In this case, the setting of the OBO-related parameters may include at least one of the OCWmin setting and the OCWmax setting. To this end, the wireless communication terminal may compare the identifier of the base station wireless communication terminal that sends the UORA parameter set element with the identifier of the base station wireless communication terminal that sends the new UORA parameter set element. In this case, the identifier of the base station wireless communication terminal may be a MAC address or a BSSID. Through this embodiment, it is possible to prevent non-associated wireless communication terminals from continuously initiating the OBO process or performing random access while damaging fairness with other wireless communication terminals.

[0192] exist Fig. 22In the embodiment, the first station STA1 is a wireless communication terminal that is not associated with any base station wireless communication terminal. The first station STA1 receives a beacon frame from the first AP AP1, and obtains a UORA parameter set element from the received beacon frame. The first station STA1 sets OBO-related parameters according to the obtained UORA parameter set element, and initializes the OBO process. Specifically, the first station STA1 sets OCWmin and OCWmax according to the obtained UORA parameter set element, and selects an arbitrary integer in OCW. In this case, the arbitrarily selected integer is 10, and the first station STA1 sets the OBO counter to 10.

[0193] The first station STA1 receives a trigger frame from the first AP AP1, the trigger frame indicating that two RUs are allocated for random access. In this case, the first station STA1 decrements the OBO counter by 2 and sets the OBO counter to 8.

[0194] The first station STA1 receives a trigger frame from the second AP AP2 indicating allocation of two RUs for random access. Because the first AP AP1 and the second AP AP2 transmitting the UORA parameter set element for setting OBO related parameters have different identifiers, the first station STA1 maintains the OBO counter as is.

[0195] The first station STA1 receives a beacon frame from the second AP AP2, and the received beacon frame includes a UORA parameter set element. Because the first AP AP1 and the second AP AP2 transmitting the UORA parameter set element for setting OBO related parameters have different identifiers, the first station STA1 does not update the OBO related parameters.

[0196] The first station STA1 receives a beacon frame from the first AP AP1 and obtains a UORA parameter set element from the received beacon frame. Because the first station STA1 receives the UORA parameter set element again from the first AP AP1 that sends the UORA parameter set element for setting the OBO related parameters, the first station STA1 updates the OBO related parameters according to the newly received UORA parameter set element.

[0197] According to reference Fig. 22 According to the described embodiment, the non-associated wireless communication terminal may not participate in the random access triggered by the base station wireless communication terminal other than the base station wireless communication terminal that receives the first UORA parameter set element. Therefore, a method for solving this problem is needed.

[0198] Fig.23 A random access operation of an associated wireless communication terminal according to an embodiment of the present invention is shown.

[0199] When the non-associated wireless communication terminal performs an OBO process for a first base station wireless communication terminal and performs an OBO process for a second base station wireless communication terminal, the non-associated wireless communication terminal may initiate an OBO process. Specifically, the non-associated wireless communication terminal may maintain OBO-related parameters and an OBO process for each base station wireless communication terminal. In a specific embodiment, the non-associated wireless communication terminal may set OBO-related parameters for each base station wireless communication terminal. Specifically, the non-associated wireless communication terminal may set OBO-related parameters for each base station wireless communication terminal based on information about OBO-related parameters received from each base station wireless communication terminal. In a specific embodiment, when the wireless communication terminal receives a UORA parameter set element from any base station wireless communication terminal, the wireless communication terminal may update the OBO-related parameters of the corresponding UORA parameter set element. In this case, the OBO-related parameters may be at least one of OCWmin and OCWmax.

[0200] In addition, the non-associated wireless communication terminal may initialize the OBO process for each base station wireless communication terminal. Specifically, the non-associated wireless communication terminal may maintain an OBO counter for each base station wireless communication terminal. In a specific embodiment, when the non-associated wireless communication terminal receives a trigger frame triggering random access from any base station wireless communication terminal, the non-associated wireless communication terminal can decrement the OBO counter for the base station wireless communication terminal based on the number of RUs of random access indicated by the corresponding trigger frame.

[0201] exist Fig.23 In the embodiment of the present invention, the first station STA1 is a wireless communication terminal that is not associated with any base station wireless communication terminal. The first station STA1 receives a beacon frame from the first AP AP1, and obtains a UORA parameter set element from the received beacon frame. The first station STA1 sets the OBO-related parameter set 1 for the first AP AP1 according to the obtained UORA parameter set element, and initializes the OBO process. Specifically, the first station STA1 sets OCWmin and OCWmax for the first AP AP1 according to the obtained UORA parameter set element, and selects a random integer for the first AP AP1 in the OCW. In this case, the randomly selected integer is 10, and the first station STA1 sets the OBO counter of the first AP AP1 to 10.

[0202] The first station STA1 receives a trigger frame from the first AP AP1, the trigger frame indicating allocation of two RUs for random access. In this case, the first station STA1 decrements the OBO counter of the first AP AP1 by 2 and sets the OBO counter of the first AP AP1 to 8.

[0203] The first station STA1 receives a beacon frame from the second AP AP2, and obtains a UORA parameter set element from the received beacon frame. Because the first AP AP1 and the second AP AP2 that send the UORA parameter set element for setting the OBO-related parameters have different identifiers, the first station STA1 sets the OBO-related parameter set 2 for the second AP AP2 according to the obtained UORA parameter set element and initializes the OBO process of the second AP AP2. Specifically, the first station STA1 sets OCWmin and OCWmax for the second AP AP2 according to the obtained UORA parameter set element, and selects a random integer for the second AP AP2 in the OCW. In this case, the randomly selected integer is 12, and the first station STA1 sets the OBO counter of the second AP AP2 to 12. In this case, the first station STA1 does not update the OBO-related parameters of the first AP AP1 and does not initialize the OBO process.

[0204] The first station STA1 receives a trigger frame from the second AP AP2, the trigger frame indicating that two RUs are allocated for random access. In this case, the first station STA1 decrements the OBO counter of the second AP AP2 by 2 and sets the OBO counter of the second AP AP2 to 10. In this case, the first station STA1 maintains the OBO counter of the first AP AP1 at 8 as it is.

[0205] according to Figure 22 to Figure 23 In the embodiment, when the wireless communication terminal does not receive information about OBO related parameters from the base station wireless communication terminal, the wireless communication terminal cannot participate in random access. Therefore, the operation of the wireless communication terminal is necessary to solve such a problem.

[0206] Fig.24 A random access operation of an associated wireless communication terminal according to an embodiment of the present invention is shown.

[0207] The non-associated wireless communication terminal may perform random access using a default value predefined for each OBO-related parameter. Specifically, the non-associated wireless communication terminal may set a predetermined value as a default value of OCWmin in OCWmin. In addition, the non-associated wireless communication terminal may set a predetermined value as a default value of OCWmax in OCWmax. In this case, the value predetermined as the default value of OCWmin may not be a value specified by the base station wireless communication terminal. In addition, the value predetermined as the default value of OCWmax may not be a value specified by the base station wireless communication terminal. Specifically, when the non-associated wireless communication terminal does not receive information about the OBO-related parameters from the base station wireless communication terminal, the non-associated wireless communication terminal may use a predetermined default value for each OBO-related parameter. In this case, when the non-associated wireless communication terminal receives information about the OBO-related parameters from the base station wireless communication terminal, the non-associated wireless communication terminal may set the OBO-related parameters according to the information about the OBO-related parameters.

[0208] In a specific embodiment, when the non-associated wireless communication terminal uses a predetermined default value for each OBO-related parameter, even if the non-associated wireless communication terminal receives information about the OBO-related parameter from the base station wireless communication terminal, the related parameter may not be set according to the information about the parameter related to OBO. In a specific embodiment, when the non-associated wireless communication terminal uses a predetermined default value for each OBO-related parameter, performs random access to the first base station wireless communication terminal, and performs random access to the second base station wireless communication terminal, the non-associated wireless communication terminal may not initiate the OBO process. For example, when the non-associated wireless communication terminal uses a predetermined default value for each OBO-related parameter, performs random access to the first base station wireless communication terminal, and performs random access to the second base station wireless communication terminal, the non-associated wireless communication terminal may use the value of the OBO counter used in the OBO process for the first base station wireless communication terminal in the random access of the second base station wireless communication terminal.

[0209] exist Fig.24 In the embodiment of the present invention, when the UORA parameter set element is not received from the base station wireless communication terminal, the first station STA1 sets OCWmin to the default value OCWmin and sets OCWmax to the OCWmax value. In this case, the first station STA1 starts the OBO process and selects 10 as a random integer within the OCW. The first station STA1 sets the randomly selected 10 as the OBO count.

[0210] The first station STA1 receives a beacon frame from the first AP AP1 and obtains a UORA parameter set element from the beacon frame. The first station STA1 does not initialize the OBO process but maintains the values ​​of the OBO related parameters as they are.

[0211] The first station STA1 receives a trigger frame indicating that two RUs are allocated for random access from the first AP AP1. In this case, the first station STA1 decrements the OBO counter by 2 and sets the OBO counter to 8.

[0212] In addition, the first station STA1 receives a trigger frame indicating that two RUs are allocated for random access from the second AP AP2. In this case, the first station STA1 decrements the OBO counter by 2 and sets the OBO counter to 6.

[0213] Fig.25 A random access operation of an associated wireless communication terminal according to an embodiment of the present invention is shown.

[0214] A non-associated wireless communication terminal may send a management frame by randomly accessing a base station wireless communication terminal. Specifically, a non-associated wireless communication terminal may send at least one of a probe request frame, an authentication request frame, and an association request frame by randomly accessing a base station wireless communication terminal. When the wireless communication terminal sends a trigger-based PPDU in response to a trigger frame, the wireless communication terminal may perform transmission in the format of an aggregated MAC protocol data unit (A-MPDU) according to a MAC padding rule. However, because the probe request frame, the authentication request frame, and the association request frame are MAC management protocol data units (MMPDUs) that do not request an immediate response, the use of A-MPDUs for transmission may not be allowed. In this case, an immediate response may indicate that a response is sent within a predetermined period within a transmission opportunity (TXOP). The predetermined period may be SIFS. It may be allowed to aggregate MMPDUs to A-MPDUs to send A-MPDUs so that they are transmitted through random access of non-associated wireless communication terminals. In this case, the MMPDU may include at least one of a probe request frame, an authentication request frame, an association request frame, and a reassociation request frame. Specifically, in the context of the content of the A-MPDU, the transmission of the MMPDU may be included in the context of data containing no immediate response request. In a specific embodiment, the probe request frame, the authentication request frame, and the association request frame may be specified with the type of MPDU that can be included in the context of data that does not require an immediate response in the context of the content of the A-MPDU. In another specific embodiment, the context of the content of the A-MPDU may be defined. Specifically, it may be specified that the context of the association process is set, the A-MPDU defined in the context of the association process does not require an immediate response, and the QoS empty frame or the action no ACK frame may be aggregated with the MMPDU. For example, it may be specified that the A-MPDU defined in the context for the association process does not require an immediate response, and that the QoS empty frame or the action no ACK frame is allowed to be aggregated with the probe request frame, the authentication request frame, or the association request frame.

[0215] exist Fig.25In an embodiment, a non-associated first station STA1 receives a beacon frame from an AP. The first station STA1 obtains a UORA parameter set element from the beacon frame and initializes the OBO process according to the obtained UORA parameter set element. The first station STA1 sets the OBO counter to 3. The first station STA1 receives a trigger frame from the AP, which indicates that four RUs are allocated for random access. The first station STA1 decrements the OBO counter to 0 based on the trigger frame. Therefore, the first station STA1 sends a triggered PPDU (HE TRIG PPDU) to the AP by allocating RUs for random access, and the triggered PPDU (HE TRIG PPDU) includes an A-MPDU into which a probe request frame or an association request frame is aggregated. The AP sends a multi-STA block Ack (M-BA) for multiple stations.

[0216] When a wireless communication terminal performing random access is scheduled to send an uplink transmission through a trigger frame, reference is made to Fig.26 The operation of the wireless communication terminal is described.

[0217] Fig.26 A random access operation of a wireless communication terminal when the wireless communication terminal according to an embodiment of the present invention schedules uplink transmission through a triggered frame is shown.

[0218] When a wireless communication terminal that performs random access through triggered frame scheduling is used for uplink transmission, whether the corresponding wireless communication terminal can decrement the OBO counter based on the RU allocated for random access indicated by the trigger frame may be a problem. Even when a wireless communication terminal that performs random access through triggered frame scheduling is used for uplink transmission, if the OBO counter is decremented based on the RU allocated for random access indicated by the trigger frame, the corresponding wireless communication terminal may have a priority that is too high than other wireless communication terminals. Therefore, the equality between wireless communication terminals can be violated. When a wireless communication terminal that performs random access through triggered frame scheduling is used for uplink transmission, the corresponding wireless communication terminal can maintain the OBO counter regardless of the number of RUs allocated for random access indicated by the trigger frame.

[0219] When a wireless communication terminal scheduled by a trigger frame for uplink transmission performs uplink transmission, the trigger frame may indicate that carrier sensing is required. In this case, when the RU to be used for uplink transmission is determined to be busy based on the result of carrier sensing, the corresponding wireless communication terminal may not attempt uplink transmission. Specifically, when a wireless communication terminal scheduled by a trigger frame for uplink transmission uses the CS required field to perform uplink transmission, the trigger frame may indicate that carrier sensing is required. Moreover, carrier sensing may include energy detection (ED). When it is determined by carrier detection that the RU to be used for uplink transmission is busy, the random access operation of the wireless communication terminal scheduled by the trigger frame for uplink transmission is a problem. This is because the uplink transmission is indicated by the trigger frame, but the corresponding wireless communication terminal does not perform uplink transmission.

[0220] When the trigger frame schedules the transmission of the wireless communication terminal performing random access on the uplink and indicates that the uplink transmission requires carrier sensing, the wireless communication terminal performing random access can operate as follows. When the RU to be used for uplink transmission is determined by carrier sensing to be busy, the wireless communication terminal performing random access can decrement the OBO counter based on the RU allocated for random access indicated by the trigger frame. Specifically, the wireless communication terminal performing random access can decrement the OBO counter by the number of RUs allocated for random access indicated by the trigger frame. In addition, when it is determined by carrier detection that the RU to be used for uplink transmission is busy, even if the OBO counter is 0 or the OBO counter reaches 0, the wireless communication terminal performing random access can maintain the OBO counter to 0 and may not attempt uplink transmission. In another specific embodiment, when it is determined by carrier detection that the RU to be used for uplink transmission is busy and the OBO counter is 0 or the OBO counter reaches 0, the wireless communication terminal performing random access can randomly select any one of the RUs allocated for random access and attempt uplink transmission.

[0221] exist Fig.26 In an embodiment, the first station STA1 receives a beacon frame from the AP. The first station STA1 obtains a UORA parameter set element from the beacon frame and initializes the OBO process according to the obtained UORA parameter set element. The first station STA1 sets the OBO counter to 3. The first station STA1 receives an indication trigger frame from the AP, which indicates that four RUs are allocated for random access and schedules the uplink transmission of the first station STA1. Because the trigger frame schedules the uplink transmission of the first station STA1, the first station STA1 maintains the OBO counter as is. In addition, the first station STA1 sends a TB PPDU (HE TRIGPPDU) to the AP according to the information indicated by the trigger frame. The AP sends a multi-STA block Ack (M-BA) for multiple stations.

[0222] In the above-mentioned embodiment, it is described that the wireless communication terminal can obtain information about the OBO counter from the beacon frame. In this way, the wireless communication terminal can obtain information about the BSS from the beacon frame. In addition, the base station wireless communication terminal can periodically send a beacon frame to signal information about the BSS. Figures 27 to 35 Describes the specific transmission method used for beacon frames.

[0223] Fig. 27 A conventional PPDU format according to an embodiment of the present invention is shown.

[0224] The type of the legacy PPDU that can be transmitted by the legacy wireless communication terminal may include at least one of a non-HT PPDU, an HT-mixed PPDU, an HT-undeveloped PPDU, and a VHT PPDU.

[0225] Fig. 27 (a) shows the format of the non-HT PPDU. The non-HT PPDU format includes: a short training field including a relatively short training signal, a long training field including a relatively long training signal, a signal field including signaling information, and a data field including a payload of the PPDU. Fig. 27 (b) shows the format of the HT-mixed PPDU. The HT-mixed PPDU includes L-STF, L-LTF, and L-SIG fields for legacy wireless communication terminals that do not support the HT-mixed PPDU. In addition, the HT-mixed PPDU includes: an HT-SIG field including signaling information, an HT-STF including a relatively short training signal, at least one HT-LTF including a relatively long training signal, and a data field including the payload of the PPDU. Fig. 27 (c) shows the format of the HT-undeveloped PPDU. The HT-undeveloped PPDU includes: an HT-GF-STF including a relatively short training signal and an HT-SIG field including signaling information, at least one HT-LTF including a relatively long training signal, and a data field including the payload of the PPDU. Fig. 27 (d) shows the format of the VHT PPDU. The VHT PPDU includes L-STF, L-LTF, and L-SIG fields for legacy wireless communication terminals that do not support the VHT PPDU. In addition, the VH PPDU includes: a VHT-SIG-A field including signaling information, a VHT-STF including a relatively short training signal, at least one VHT-LTF including a relatively long training signal, and a data field including the payload of the PPDU. In addition, the VHT PPDU may include a VHT-SIG-B field for signaling additional information.

[0226] Fig.28 A non-legacy PPDU format according to an embodiment of the present invention is shown.

[0227] The wireless communication terminal according to an embodiment of the present invention may support one or more non-traditional PPDU formats. In addition, the wireless communication terminal according to an embodiment of the present invention may select and use any one of a plurality of non-traditional PPDU formats according to the purpose and purpose of sending the PPDU. Specifically, the wireless communication terminal may support at least one of HE SU PPDU, HE MUPPDU, HE extended range SU PPDU, and HE-triggered PPDU. The HE-SIG-A field and the HE-SIG-B field of the non-traditional PPDU may be referred to as the pre-HE modulation field. In addition, the HE-STF, HE-LTF, and date fields of the non-traditional PPDU may be referred to as HE modulation fields. The pre-HE modulation field and the HE modulation field can be modulated with different parameter sets.

[0228] Fig.28 (a) shows the format of the HE SU PPDU. The wireless communication terminal may use the HE SU PPDU for single user (SU) transmission. The HE SU PPDU may include L-STF, L-LTF, and L-SIG fields for a legacy wireless communication terminal. In addition, the HE SU PPDU includes an RL-SIG for signaling a non-legacy PPDU, a HE-SIG-A field including signaling information, a HE-STF including a relatively short training signal, at least one HE-LTF including a relatively long training signal, and a data field including a payload of the PPDU. In addition, the HE SU PPDU may include a packet extension (PE) field for ensuring processing time. The duration of the PE field may be determined by a TXVECTOR parameter PE_DURATION. The HE SU PPDU is capable of delivering one PSDU.

[0229] Fig.28 (b) shows the format of the HE MU PPDU. The wireless communication terminal may use the HE MU PPDU to transmit to one or more users. In this case, the wireless communication terminal may not use the HE MU PPDU in response to a trigger. The HE MU PPDU has a format similar to that of the HE SU PPDU and may also include a HE-SIG-B field compared to the HE SU PPDU. The HE-SIG-B field includes information for multi-user (MU) transmission. The HE MU PPDU may deliver more than one PSDU.

[0230] Fig.28(c) shows the format of the HE-triggered PPDU. In the above embodiment, the TB PPDU may refer to the HE-triggered PPDU. The wireless communication terminal may use the HE-triggered PPDU to respond to the trigger frame or the UL MU response scheduling A-control field. The HE-triggered PPDU may include a HE-STF, which includes a longer duration than the HE SU PPDU format.

[0231] Fig.28 (d) shows the format of the HE extended range SU PPDU. The wireless communication terminal can use the HE extended range SUPPDU for extended range transmission. The HE extended range SU PPDU has a format similar to the HE SU PPDU, and the duration of the HE-SIG-A field of the HE extended range SU PPDU is twice the duration of the HE-SIG-A field of the HE SU PPDU. The wireless communication terminal is able to perform transmission using four symbols. For example, four symbols can be sent in the HE-SIG-A field of the HE extended range SU PPDU. The four symbols used to send the HE-SIG-A field can be symbols repeated in the time domain. The four symbols that send the HE-SIG-A field are called HE-SIG-A1, HE-SIG-A2, HE-SIG-A3 and HE-SIG-A4 in chronological order. In this case, HE-SIG-A1 and HE-SIG-A2 can send the same signal, and HE-SIG-A3 and HE-SIG-A4 can send the same signal. In addition, when sending the HE extended range SU PPDU, the wireless communication terminal can increase the transmission power by 3dB compared to the case of sending the L-STF and L-LTF of other non-legacy PPDUs. In addition, when sending the four additional tones of the L-SIG field and the RL-SIG field (subcarrier index k = -28, -27, 27 and 28), the wireless communication terminal can increase the transmission power by 3dB compared to when sending the L-STF and L-LTF of other non-legacy PPDUs. Through these operations, the wireless communication terminal can increase the reception probability of the HE extended range SU PPDU.

[0232] Fig.29 The coverage of the HE extended range SU PPDU and the transmission coverage of the conventional PPDU according to an embodiment of the present invention are shown.

[0233] As reference Fig.28As described above, when transmitting the HE extended range SU PPDU, the wireless communication terminal performs various operations for long-distance transmission. Therefore, the transmission coverage of the HE extended range SU PPDU is wider than the transmission coverage of the conventional PPDU. Due to this, even a wireless communication terminal capable of receiving the HE extended range SU PPDU may not receive the conventional PPDU format. For example, in Fig.29 In the case shown, the transmission coverage of the HE extended range SU PPDU is wider than the transmission coverage of the traditional PPDU (non-HE PPDU). Therefore, the first station STA1 can receive both the traditional PPDU (non-HE PPDU) and the HE extended range SU PPDU. The second station STA2 can only receive the HE extended range SU PPDU without receiving the traditional PPDU (non-HE PPDU). When there is information to be sent using the traditional PPDU format, the wireless communication terminal outside the coverage of the traditional PPDU format cannot use the information. The wireless communication terminal can use the traditional PPDU format to send a beacon frame. Although the wireless communication terminal outside the coverage of the traditional PPDU format can communicate with the base station wireless communication terminal using the HE extended range SU PPDU, it cannot receive the BSS information and, therefore, cannot communicate with the base station wireless communication terminal. Therefore, the base station wireless communication terminal can send a dual beacon frame. Reference will be made to Fig.30 Describe this.

[0234] Fig.30 The dual beacon transmission operation of the base station wireless communication terminal according to the embodiment of the present invention is shown.

[0235] The base station wireless communication terminal can use multiple PPDU formats to send beacon frames. Specifically, the base station wireless communication terminal can use two PPDU formats with different transmission coverage to send beacon frames. The wireless communication terminal can send beacon frames using the traditional PPDU format, and send beacon frames using the PPDU format for wide range transmission. In this case, the PPDU format for wide range transmission can be the above-mentioned HE extended range SU PPDU. Through this operation, the base station wireless communication terminal can increase the possibility of wireless communication terminals around the base station wireless communication terminal receiving beacon frames. For ease of explanation, the fact that the base station wireless communication terminal sends beacon frames using two PPDU formats with different transmission coverage is called dual beacon.

[0236] The base station wireless communication terminal may send a beacon frame based on a predetermined period of time. In this case, the time point at which the base station wireless communication terminal attempts to send a beacon frame may be referred to as a target beacon transmission time (TBTT). The TBTT may continue at a predetermined time interval. In this case, the predetermined time interval may be referred to as a beacon interval. When the channel on which the base station wireless communication terminal sends a beacon frame is busy, the base station wireless communication terminal may try to send a beacon frame again after a predetermined time. For example, when the channel on which the base station wireless communication terminal sends a beacon frame is idle, the base station wireless communication terminal may send a beacon frame.

[0237] The base station wireless communication terminal may attempt to send a traditional PPDU including a beacon frame in a TBTT, and attempt to send a PPDU for wide range transmission including a beacon frame after a predetermined time from the TBTT. At this time, the predetermined time may be half of the time interval between the TBTTs. For example, the TBTT of a beacon frame included in a traditional PPDU may be a timing synchronization function (TSF) value of 0, and the TBTT of a beacon frame included in a traditional PPDU may be repeated for each beacon interval. The TBTT of a beacon frame included in a PPDU for wide range transmission may be a time point that passes half of the beacon interval starting from the TSF value of 0. In addition, the TBTT of a beacon frame included in a PPDU for wide range transmission may also be repeated for each beacon interval.

[0238] The base station wireless communication terminal may use an operation element to signal whether to use dual beacons. In this case, the operation element may be a HE operation element. In addition, each beacon frame sent through different PPDU formats may include different types of signaling information. Specifically, each beacon frame sent through different PPDU formats may include different types of elements.

[0239] exist Fig.30 In an embodiment of the present invention, the base station wireless communication terminal attempts to send a traditional PPDU including a beacon frame in a TBTT for a traditional PPDU including a beacon frame. The base station wireless communication terminal sends a traditional PPDU including a beacon frame, and the first station STA1 receives the traditional PPDU including the beacon frame. The second station STA2, which is farther from the base station wireless communication terminal than the first station STA1, does not receive the traditional PPDU including the beacon frame.

[0240] At a time point when half of the beacon interval of the conventional PPDU including the beacon frame has passed from the TBTT for the conventional PPDU including the beacon frame, the base station wireless communication terminal attempts to transmit the HE extended range SU PPDU including the beacon frame. The base station wireless communication terminal transmits the HE extended range SU PPDU including the beacon frame, and the first station STA1 and the second station STA2 receive the HE extended range SU PPDU including the beacon frame.

[0241] At a time point when the beacon interval has passed from the TBTT for the conventional PPDU including the beacon frame, the base station wireless communication terminal attempts to send the conventional PPDU including the beacon frame. At a time point when half the beacon interval has passed from this time, the base station wireless communication terminal attempts to send the HE extended range SU PPDU including the beacon frame.

[0242] The base station wireless communication terminal can use the above-mentioned TBTT to signal information about a specific time point. For example, the base station wireless communication terminal can use the TBTT to signal the start time point of the change of the BSS color, which is an identifier indicating the BSS. Fig.31 This is described in more detail.

[0243] Fig.31 The format of the BSS color change declaration element according to an embodiment of the present invention is shown.

[0244] The base station wireless communication terminal may send a beacon frame including a BSS color change announcement element to notify the change of the BSS color and the new BSS color value. In this case, the BSS color change announcement element may include a field indicating the time point of the BSS color change. In addition, the BSS color change announcement element may include a field indicating the value of the changed BSS color. For example, the BSS color change announcement element may include a color switch countdown field. The color switch countdown field may indicate the number of TBTTs remaining before the BSS color change time point. The BSS color change announcement element may include a new BSS color information field. The new BSS color information field may indicate a new BSS color value to be used as the BSS color of the corresponding BSS. The new BSS color information field may include a new BSS color subfield, and the new BSS color subfield may indicate the value of the new BSS color to be used as the BSS color of the corresponding BSS. The specific format of the BSS color change announcement element may be the same as Fig.31 Same as shown in .

[0245] For ease of explanation, the TBTT in which the color switching countdown value reaches 0 and the BSS color is changed is called the BSS color change TBTT. Before reaching the BSS color change TBTT, the base station wireless communication terminal inserts the BSS color value before the BSS change into the BSS color subfield of the HE operation element. In addition, when the BSS color change TBTT is reached, the base station wireless communication terminal sets the BSS color disable subfield of the HE operation element to 0, inserts the changed BSS color value into the BSS color subfield of the HE operation element, and starts using the changed value of the BSS color. In addition, the wireless communication terminal receiving the BSS color change declaration element can use the changed BSS color value from the BSS color change TBTT. In this case, the wireless communication terminal obtains the changed value of the BSS color from the BSS color change notification element.

[0246] In order to make all wireless communication terminals in the BSS use the same BSS color value, the base station wireless communication terminal and the wireless communication terminal can operate as follows. The base station wireless communication terminal that sends the BSS color change declaration element can use the previous BSS color value until the BSS color change TBTT is reached, and use the changed BSS color value after the BSS color change TBTT. In addition, until the base station wireless communication terminal that sends the BSS color change declaration element reaches the BSS color change TBTT, the BSS color change TBTT indicated by the BSS color change declaration element may not be allowed to be changed. When the base station wireless communication terminal uses dual beacons, the BSS color change time point can be determined differently according to the format of the PPDU that the wireless communication terminal can receive. Reference Fig.32 Describe this.

[0247] Fig.32 A BSS color change operation of a base station wireless communication terminal when the base station wireless communication terminal uses dual beacons according to an embodiment of the present invention is shown.

[0248] Due to the distance between the wireless communication terminal and the base station wireless communication terminal, the wireless communication terminal may only receive one PPDU format in the PPDU format for dual beacons. In this case, a wireless communication terminal that receives only one PPDU format of the PPDU format for dual beacons may determine the BSS color change TBTT differently from a wireless communication terminal that receives all PPDU formats for dual beacons. Specifically, because the wireless communication terminal may not recognize the transmission of the beacon frame included in the PPDU format that the wireless communication terminal may not receive, it may not be possible to accurately determine the number of TBTTs remaining until the BSS color changes. In addition, a wireless communication terminal that receives all PPDU formats for dual beacons may be confused about how to set the TBTT standard when determining the BSS color change TBTT. For example, a wireless communication terminal that receives all PPDU formats for dual beacons may have difficulty determining whether the value indicated by the countdown field indicates a TBTI of all types of PPDUs including beacon frames or a TBTT of a specific type of PPDU format that only includes beacon frames.

[0249] exist Fig.32 In an embodiment of the present invention, the base station wireless communication terminal attempts to send a traditional PPDU including a beacon frame in a TBTT for a traditional PPDU including a beacon frame. The base station wireless communication terminal sends a traditional PPDU including a beacon frame, and the first station STA1 receives the traditional PPDU including the beacon frame. The second station STA2, which is farther away from the base station wireless communication terminal than the first station STA1, does not receive the traditional PPDU including the beacon frame.

[0250] At a time point when half of the beacon interval of the conventional PPDU including the beacon frame has passed from the TBTT for the conventional PPDU including the beacon frame, the base station wireless communication terminal attempts to transmit the HE extended range SU PPDU including the beacon frame. The base station wireless communication terminal transmits the HE extended range SU PPDU including the beacon frame and the first station STA1 and the second station STA2 receive the HE extended range SU PPDU including the beacon frame.

[0251] In this case, the beacon frame included in the legacy PPDU signals the BSS color change TBTT based on the TBTT of the beacon frame included in the legacy PPDU. The beacon frame included in the legacy PPDU can signal the remaining TBTT count until the first time point (BSS color change TBTT 1) at which the BSS color changes and the legacy PPDU including the first beacon frame is transmitted. The beacon frame included in the PPDU for wide range transmission signals the BSS color change TBTT based on the TBTT of the beacon frame included in the PPDU for wide range transmission. The beacon frame included in the PPDU for wide range transmission can signal the remaining TBTT count until the second time point (BSS color change TBTT 2) at which the BSS color changes and the PPDU for wide range transmission including the first beacon frame is transmitted. Since the first station STA1 can receive two types of PPDU formats including the beacon frame, it may not be determined at which time point the BSS color changes, the first time point (BSS color change TBTT 1) or the second time point (BSS color change TBTT 2). In addition, the second station STA2 does not receive information about the first time point (BSS color change TBTT1). Therefore, the BSS color change time points of the first station STA1 and the second station STA2 may be different. As a result, interference may occur because of wireless communication terminals included in the same BSS and using different BSS color values.

[0252] The wireless communication terminal may perform operations other than the BSS color change operation based on the TBTT. For example, the wireless communication terminal may receive a UORA parameter element set related to random access in the TBTT, and perform operations according to the reception of the UORA parameter element set. The operation according to the reception of the UORA parameter element set may include at least one of OBO-related parameter setting and OBO process initialization. As a result, when the base station wireless communication terminal uses dual beacons, there may be a problem that the time point at which the wireless communication terminal receives the UORA parameter element set related to random access and performs operations according to the reception of the UORA parameter element set becomes unclear. In addition, a wireless communication terminal located relatively close to the base station wireless communication terminal may receive the UORA parameter element set more frequently than a wireless communication terminal located relatively far away from the base station wireless communication terminal. Therefore, a wireless communication terminal located relatively close to the base station wireless communication terminal may perform the OBO process more frequently than a wireless communication terminal located relatively far away from the base station wireless communication terminal. As a result, equality between wireless communication terminals for random access may be a problem. For ease of explanation, the operation in which the wireless communication terminal determines the time point at which the operation is performed based on the TBTT is referred to as an operation based on the TBTT. Reference will be made to Figure 33 to Figure 34An embodiment is described in which a wireless communication terminal can perform an operation based on TBTT without any problem even when the base station wireless communication terminal uses dual beacons.

[0253] Fig.33 A BSS color change operation of a base station wireless communication terminal when the base station wireless communication terminal uses dual beacons according to another embodiment of the present invention is shown.

[0254] When the base station wireless communication terminal uses dual beacons, the wireless communication terminal may perform TBTT-based operations in the TBTT of a beacon frame included in one PPDU format, and may not perform TBTT-based operations in the TBTT of a beacon frame included in another PPDU format. Specifically, the wireless communication terminal may perform TBTT-based operations on the TBTT of a beacon frame included in a traditional PPDU, and may not perform TBTT-based operations on the TBTT of a beacon frame included in a PPDU for wide-range transmission. In another specific embodiment, specifically, the wireless communication terminal may perform TBTT-based operations on the TBTT of a beacon frame included in a PPDU for wide-range transmission, without performing TBTT-based operations on the TBTT of a beacon frame included in a traditional PPDU. For ease of explanation, the format of the PPDU of a beacon frame sent at the TBTT where the wireless communication terminal performs TBTT-based operations is referred to as a reference PPDU format. Beacons included in PPDU formats other than the reference PPDU format may also signal information related to TBTT reference operations. In this case, information related to the TBTT reference operation signaled by a beacon included in the reference PPDU format and information related to the TBTT reference operation signaled by a beacon included in a PPDU format other than the reference PPDU format may indicate the same information.

[0255] In such an embodiment, the BSS color change announcement element may indicate the same BSS color change time point, regardless of the format of the PPDU including the BSS color change announcement element. In addition, the color switch countdown field may indicate the number of times the reference PPDU format including the remaining beacon frames is sent before the BSS color is changed. If the color switch countdown field included in the PPDU format other than the reference PPDU format is 0, the color switch countdown field may indicate that the BSS color changes when the reference PPDU format including the beacon frame is sent. For example, when the wireless communication terminal changes the BSS color in the TBTT of the beacon frame included in the traditional PPDU, the color switch countdown field may indicate the number of times the traditional PPDU including the remaining beacon frames is sent before the BSS color changes. In this case, when the color switch countdown field of the beacon frame included in the PPDU for wide range transmission indicates 0, the wireless communication terminal may determine to change the BSS color at the TBTT of the beacon frame included in the traditional PPDU sent after the corresponding beacon frame. In addition, when the color switching countdown field of the beacon frame included in the legacy PPDU indicates 0, the wireless communication terminal can determine to change the BSS color at the TBTT of the corresponding beacon frame.

[0256] In another specific embodiment, when the wireless communication terminal changes the BSS color in the TBTT of the beacon frame included in the PPDU for wide range transmission, the color switching countdown field may indicate the number of times the PPDU for wide range transmission including the remaining beacon frames is sent before the BSS color is changed. In this case, when the color switching countdown field of the beacon frame included in the conventional PPDU indicates 0, the wireless communication terminal is able to determine that the BSS color is changed in the TBTT of the beacon frame included in the PPDU for wide range transmission sent after the corresponding beacon frame. In addition, when the color switching countdown field of the beacon frame included in the PPDU for wide range transmission indicates 0, the wireless communication terminal is able to determine that the BSS color is changed in the TBTT of the corresponding beacon frame.

[0257] exist Fig.33 In an embodiment of the present invention, the BSS color is changed at the TBTT of the beacon frame included in the legacy PPDU (non-HE format). Therefore, the beacon frame included in the HE extended range SU PPDU and the beacon frame included in the legacy PPDU (non-HE format) use a signal to send the TBTT of the beacon frame included in the legacy PPDU (non-HE format) as the BSS color change time point. Therefore, the first station STA1 and the second station STA2 are able to change the BSS color based on the same time point. In the operation of the base station wireless communication terminal, the first station STA1 and the second station STA2, the description is as follows Fig.31 The same operation as in the embodiment.

[0258] In another specific embodiment, the wireless communication terminal may update OBO-related parameters based on the UORA parameter set element in the TBTT of the beacon frame included in the PPDU for wide range transmission, and may not update OBO-related parameters based on the UORA parameter set element in the TBTT of the beacon frame included in the traditional PPDU. In addition, the wireless communication terminal may initialize the OBO process based on the UORA parameter set element in the TBTT of the beacon frame included in the PPDU for wide range transmission, and may not initialize the OBO process based on the UORA parameter set element in the TBTT of the beacon frame included in the traditional PPDU.

[0259] Fig.34 A BSS color change operation of a base station wireless communication terminal when the base station wireless communication terminal uses dual beacons according to another embodiment of the present invention is shown.

[0260] When the base station wireless communication terminal uses dual beacons, the base station wireless communication terminal may signal information related to TBTT-based operations through a beacon frame included in one PPDU format, and may not signal information related to TBTT-based operations through a beacon frame included in other types of PPDU formats. Specifically, the base station wireless communication terminal may signal information related to TBTT-based operations through a beacon frame included in a traditional PPDU, and may not signal information related to TBTT-based operations through a beacon frame included in a PPDU for wide-range transmission. Also in these embodiments, reference may be specified. Fig.33 Describes a reference PPDU format. The reference PPDU format may be a PPDU format that includes beacon signaling information related to TBTT-based operations. In addition, the PPDU format that includes beacon signaling information related to TBTT-based operations may be a format of a PPDU having a wider transmission coverage than other PPDU formats. This is because, when the transmission coverage of the PPDU format that includes beacon signaling information related to TBTT-based operations is wider, more wireless communication terminals are able to receive information related to TBTT-based operations.

[0261] In a specific embodiment, the base station wireless communication terminal may signal the BSS color change announcement element through a beacon frame included in the PPDU for wide range transmission, and may not signal the BSS color change notification element through a beacon frame included in the traditional PPDU. Even in this embodiment, a reference PPDU format may be specified. Specifically, the reference PPDU format may be a PPDU for wide range transmission.

[0262] exist Fig.34In an embodiment of the present invention, the base station wireless communication terminal transmits the BSS color change announcement element through a beacon frame included in the HE extended range SU PPDU, and does not transmit the BSS color change announcement element through a beacon frame (non-HE format) included in the legacy PPDU. In addition, the BSS color is changed based on the TBTT of the beacon frame included in the HE extended range SU PPDU. In the operations of the base station wireless communication terminal, the first station STA1 and the second station STA2, the BSS color change announcement element is omitted. Fig.31 The operations in the embodiments are the same as those described above.

[0263] In another specific embodiment, the base station wireless communication terminal may transmit the UORA parameter set element through a beacon frame included in a PPDU for wide range transmission, and may not transmit the UORA parameter set element through a beacon frame included in a legacy PPDU.

[0264] The base station wireless communication terminal may use STBC to send beacon frames. In this case, the sent beacon frame may be referred to as an STBC beacon frame. When the base station wireless communication terminal uses both the STBC beacon frame and the beacon frame included in the HE extended range SU PPDU, the transmission time point of the STBC beacon frame and the transmission time point of the HE extended range SU PPDU may overlap. Moreover, it may be difficult for a wireless communication terminal receiving a beacon frame to determine which beacon frame is sent at which time point. Therefore, the base station wireless communication terminal may not operate the STBC beacon frame and the beacon frame included in the HE extended range SU PPDU together. For example, when the base station wireless communication terminal uses the beacon frame included in the HE extended range SU PPDU, the base station wireless communication terminal may not use the STBC beacon frame. In addition, when the base station wireless communication terminal starts using the beacon frame included in the HE extended range SU PPDU, the base station wireless communication terminal may stop using the STBC beacon frame.

[0265] The base station wireless communication terminal may use the dual beacon field of the HT operation element to indicate whether to use the STBC beacon frame. In addition, the base station wireless communication terminal may use the dual beacon field of the HT operation element to indicate whether to use the beacon frame included in the HE extended range SU PPDU. When the dual beacon field of the HT operation element signals that the STBC beacon frame and any one of the beacon frames included in the HE extended range SU PPDU is used, the dual beacon field of the HT operation element may indicate that the other beacon frame is not used. For example, when the dual beacon field of the HE operation element indicates that the STBC beacon frame is used, the dual beacon field of the HE operation element may indicate that the beacon frame included in the HE extended range SU PPDU is not used. Therefore, when the dual beacon field of the HE operation element is 1, the dual beacon field of the HE operation element may indicate that the STBC beacon frame is not used.

[0266] The wireless communication terminal can transmit one MPDU or an aggregated MPDU (A-MPDU) as a physical layer service data unit (PSDU) of a PPDU. In this case, the wireless communication terminal can aggregate multiple MPDUs to generate one aggregated MAC protocol data unit (A-MPDU). The wireless communication terminal can increase transmission efficiency by transmitting an A-MPDU instead of dividing multiple MPDUs into multiple PPDUs and transmitting the multiple PPDUs. Fig.35 Describes the specific format of the A-MPDU.

[0267] Fig.35 The format of the A-MPDU according to an embodiment of the present invention is shown.

[0268] The A-MPDU may include a sequence of one or more A-MPDU subframes and EOF padding. The boundaries between A-MPDU subframes may be distinguished by the MPDU delimiter field. The MPDU may follow the MPDU delimiter field. When the A-MPDU subframe is not the last A-MPDU subframe, the A-MPDU subframe may include a padding octet. The wireless communication terminal may set the padding octet so that the length of each A-MPDU subframe is a multiple of 4 octets. The length of the padding subfield included in the last A-MPDU subframe may be 0 to 3 octets.

[0269] The MPDU Delimiter field may be 4 octets in length. The specific format of the MPDU Delimiter field may be the same as Fig.35. In this case, the MPDU delimiter field may be the format of the MPDU delimiter field sent by the non-DMG wireless communication terminal. The MPDU delimiter field may include at least one of the EOF subfield, the reserved subfield, the MPDU length subfield, the CRC subfield, and the delimiter signature subfield. The EOF subfield may be a 1-bit field. The wireless communication terminal sets the MPDU length subfield of the A-MPDU subframe to 0 and the EOF subfield to 1, thereby indicating that the corresponding A-MPDU subframe is an EOF padding subframe. In addition, the wireless communication terminal sets the EOF subfield to 1 and sets the MPDU length subfield to a non-zero value to indicate that the corresponding A-MPDU subframe is a VHT single MPDU or a single MPDU (S-MPDU). A VHT single MPDU or a single MPDU is only one MPDU in the corresponding A-MPDU. In other cases, the wireless communication terminal may set the EOF field to 0. The MPDU length subfield may indicate the length of the MPDU including the A-MPDU subframe in units of eight bits. When the A-MPDU subframe does not include an MPDU, the wireless communication terminal sets the MPDU length field to 0. The CRC subfield may include a 16-bit CRC value included in the MPDU Delimiter field. The CRC field may be an 8-bit field. The Delimiter Signature subfield may include a value set for identifying the MPDU Delimiter. In this case, the set value may be 0x4E.

[0270] The length of the EOF padding field may be variable. The EOF padding field may include an EOF padding subframe and an EOF padding octet. The EOF padding field may optionally include one or more EOF padding subframes. The MPDU delimiter field may include an MPDU length field and an EOF field. The wireless communication terminal sets the MPDU length subfield of the A-MPDU subframe to 0 and sets the EOF subfield to 1, thereby indicating that the corresponding A-MPDU subframe is an EOF padding subframe. The length of the EOF padding octet subfield may be 0 to 3 octets.

[0271] As described above, the wireless communication terminal may signal information about the A-MPDU subframe through the value of the EOF field. In this case, the wireless communication terminal may configure the A-MPDU according to the following rules.

[0272] - An A-MPDU subframe in which the EOF subfield is set to 0 in the A-MPDU is not located after an A-MPDU subframe in which the EOF subfield is set to 1.

[0273] - An A-MPDU subframe in which the EOF subfield is set to 1 and the MPDU length subfield is set to 0 in the A-MPDU does not precede an A-MPDU subframe including a VHT single MPDU.

[0274] In addition, the wireless communication terminal may set a predetermined value in the EOF subfield and request an immediate response to the MPDU included in the A-MPDU. Specifically, when a frame is transmitted through an A-MPDU or a multi-TID A-MPDU, the wireless communication terminal transmitting the PPDU requests an immediate response by setting the Ack policy field of a QoS data frame or a QoS null frame, transmitting a specific type of frame (e.g., an action frame, a BAR frame, or a MU-BAR frame), or setting the EOF subfield to a predetermined value.

[0275] A multi-TID A-MPDU refers to an MPDU generated by associating multiple MPDUs with different service identifiers (TIDs). Specifically, a multi-TID A-MPDU may be an A-MPDU including multiple QoS data frames with different TIDs. The wireless communication terminal may use the value of a subfield of the MPDU delimiter field included in the multi-TID A-MPDU to request a specific type of response to the MPDU included in the A-MPDU subframe. Specifically, when the wireless communication terminal generates a multi-TID A-MPDU, the wireless communication terminal may set the MPDU length subfield of the MPDU delimiter field to a non-zero value and set the value of the EOF subfield to 0 to request immediate ACK frame transmission for the QoS data frame or action frame included in the A-MPDU subframe corresponding to the MPDU delimiter field. In addition, the wireless communication terminal may set multiple discontinuous MPDU delimiter fields, wherein the EOF subfield is 1 and the MPDU length field has a non-zero value, to request an ACK for the MPDU included in each of the multiple MPDU delimiter fields. In addition, the wireless communication terminal may set a plurality of discontinuous MPDU delimiter fields in which the EOF subfield is 0 and the MPDU length field has a non-zero value to request a block Ack for the MPDU included in each of the plurality of MPDU delimiter fields. The wireless communication terminal may aggregate the A-MPDU by combining an A-MPDU subframe including an MPDU delimiter field in which the EOF subfield is 1 and the MPDU length subfield is not 0 and an A-MPDU subframe including an MPDU delimiter field in which the EOF subfield is 0 and the MPDU length subfield is not 0. In addition, the wireless communication terminal may discontinuously aggregate A-MPDU subframes having the same TID to generate a multi-TID A-MPDU.

[0276] The wireless communication terminal receiving the multi-TID A-MPDU may send a multi-STA Block Ack in response to the multi-TID A-MPDU. In this case, the multi-STA Block Ack may include the following per-STA information fields.

[0277] - A per-STA information field indicating an ACK for successfully receiving an MPDU corresponding to the MPDU length field whose EOF subfield value is 1, having a non-zero length (In this case, the TID value of the MPDU may indicate the TID of a QoS data frame or a QoS null frame. In addition, the TID value of the MPDU may be 15, which indicates an action frame.)

[0278] - A Per-STA Information field indicating a Block Ack for successfully receiving an MPDU corresponding to the MPDU Length field in which the EOF subfield value is 0, having a non-zero length (in this case, the TID value of the MPDU may be the TID value of the QoS data frame.)

[0279] Will refer to Fig.36 Describes the specific format of Block Ack.

[0280] Fig.36 A specific format of Block Ack according to an embodiment of the present invention is shown.

[0281] The block Ack frame may include at least one of a frame control field, a duration field, a RA field, a TA field, a BA control field, a BA information field, and an FCS field. The frame control field, the duration field, the RA field, and the TA field correspond to the MAC header. When the block Ack frame is not a multi-STA block Ack variant, the wireless communication terminal may set the RA field to the TA field of the frame requesting the block Ack frame. In addition, when the block Ack frame is not a multi-STA block Ack variant, the wireless communication terminal may set the RA field to the address of the wireless communication terminal that sends the data / management frame as an ACK with the block Ack frame.

[0282] When the Block Ack frame is: the Multi-STA Block Ack frame is a Multi-STA Block Ack variant and the value of the AID subfield of the Per-STA Information subfield included in the Multi-STA Block Ack variant is two or more, the wireless communication terminal may set the RA field to the broadcast address. When the Block Ack frame is: the Multi-STA Block Ack frame is a Multi-STA Block Ack variant and the value of the AID subfield of the Per-STA Information subfield included in the Multi-STA Block Ack variant is 1, the wireless communication terminal may set the RA field to the address of the wireless communication terminal requesting the Block Ack, or may set it to the broadcast address. When the Block Ack frame is: the Multi-STA Block Ack frame is a Multi-STA Block Ack variant and the value of the AID subfield of the Per-STA Information subfield included in the Multi-STA Block Ack variant is 1, the wireless communication terminal may set the RA field to the address of the wireless communication terminal requesting the Block Ack, or may set it to the address of the wireless communication terminal sending the data / management frame as an ACK with the Block Ack frame. In addition, when the value of the AID subfield of the per STA information subfield included in the Multi-STA Block Ack variant is 1, the Multi-STA Block Ack variant may include only one AID subfield of the per STA information subfield or multiple AID subfields of the per STA information subfield having the same value.

[0283] In addition, the BA Control field may include at least one of a BA Ack Measurement subfield, a BA Type subfield, a TID_INFO subfield, and a Reserved subfield, such as Fig.36 As shown in . The BA type subfield may include at least one of the existing multi-TID subfield, the compression bitmap subfield, and the GCR subfield. Specifically, B1 of the BA type may be the same as the existing multi-TID subfield. In addition, B2 of the BA type may be the same as the existing compression bitmap subfield. In addition, B3 of the BA type may be the same as the existing GCR subfield.

[0284] In a specific embodiment, the wireless communication terminal may use the BA type subfield to signal a block Ack frame. The wireless communication terminal may set the BA type subfield to a predetermined value to indicate that the block Ack frame is a multi-STA block Ack variant. For example, the wireless communication terminal may set B1-B4 of the BA type subfield to 1101 to indicate that the block Ack frame is a multi-STA block Ack variant. The block Ack frame is a multi-STA block Ack variant and may be referred to as a multi-STA block Ack frame. In addition, the wireless communication terminal may use the BA type subfield to indicate whether the block Ack frame is a basic block Ack, a compressed block Ack, a GLK-GCR block Ack, a GCR block Ack, an extended compressed block Ack, a multi-TID block Ack, or a multi-STA block Ack.

[0285] In addition, the information indicated by the TID_INFO subfield may vary according to the Block Ack frame variant type. Specifically, the information indicated by the TID_INFO subfield may vary according to the type of the Block Ack frame. When the Block Ack frame is a multi-STA Block Ack, the TID_INFO subfield may be a reserved field.

[0286] In addition, the information indicated by the BA information field may vary depending on the Block Ack frame variant type. Specifically, when the Block Ack frame is a multi-STA Block Ack variant, the BA information field may include Fig.37 One or more per-STA information subfields. Fig.37 The specific format of each STA information subfield is described in detail. In this specification, receiving an MPDU / frame may refer to successfully receiving an MPDU or frame. Specifically, if the value of the frame check sequence (FCS) obtained based on the received MPDU / frame is equal to the value of the FCS field, the wireless communication terminal can determine that the MPDU / frame is successfully received.

[0287] Fig.37 A per-STA information subfield according to an embodiment of the present invention is shown.

[0288] The BA Information field of the Multi-STA Block Ack may include one or more Per-STA Information fields.

[0289] The per-STA information subfield may include a per-AID TID information subfield. The per-AID TID information subfield may include at least one of an AID subfield, an Ack type subfield, and a TID subfield. When a multi-STA block Ack frame is to be sent to a wireless communication terminal other than a base station wireless communication terminal, the wireless communication terminal may set the AID subfield to the 11 LSBs of the AID of the corresponding wireless communication terminal. When a multi-STA block Ack frame is to be sent to a wireless communication terminal other than a base station wireless communication terminal, the wireless communication terminal may set the AID subfield to the AID of the corresponding wireless communication terminal. When it is intended to send a multi-STA block Ack frame to a base station wireless communication terminal, the wireless communication terminal may set the AID subfield to 0.

[0290] One multi-STA Block Ack frame may include multiple per-STA information subfields, wherein the AID subfield has the same value. In this case, the values ​​of the TID subfields of the multiple per-STA information subfields may be different from each other.

[0291] The TID subfield indicates the TID of the frame per AID TID Information subfield ACK. When the per AID TID Information subfield ACK management frame of the Multi-STA Block Ack variant, the wireless communication terminal may set the TID subfield to 15.

[0292] In addition, the Ack Type subfield may indicate whether a Block Ack Starting Sequence Control subfield and a Block Ack Bitmap subfield exist in the Per STA Information subfield corresponding to the Ack Type subfield. Fig.38 This is described in more detail.

[0293] Fig.38 The context of the Per-STA Information subfield according to an embodiment of the present invention is shown.

[0294] When the Ack Type subfield is 1 and the value of the TID subfield of the Per-AID TID Information subfield is less than or equal to 8 or 15, the Ack Type subfield and the TID subfield may indicate that the Block Ack Starting Sequence Control subfield and the Block Ack Bitmap subfield do not exist. In this case, the Per-STA Information subfield corresponding to the Ack Type field may be ACK, i.e., a single MPDU indicated by the TID subfield of the Per-AID TID Information subfield is successfully received.

[0295] In addition, when the Ack Type subfield is 1 and the value of the TID subfield of the Per-AID TID Information subfield is 14, the Ack Type subfield and the TID subfield may indicate that the Block Ack Starting Sequence Control subfield and the Block Ack Bitmap subfield do not exist. In this case, the Per-STA Information subfield corresponding to the Ack Type field may be ACK, that is, all MPDUs including the A-MPDU of the frame indicated by the TID subfield of the Per-AID TID Information subfield are successfully received.

[0296] In addition, when the Ack Type subfield is 0, the Ack Type subfield may indicate the presence of the Block Ack Start Sequence Control subfield and the Block Ack Bitmap subfield. In addition, the specific context of the Per STA Information subfield may be Fig.38 Same as shown in .

[0297] Will refer to Figure 39 to Figure 40 A specific method for a wireless communication terminal to receive a multi-TID A-MPDU to generate a multi-STA block Ack frame is described. For ease of explanation, a wireless communication terminal that sends a multi-TID A-MPDU is called a multi-TID A-MPDU transmitter, and a wireless communication terminal that receives a multi-TID A-MPDU is called a multi-TID A-MPDU receiver.

[0298] Figures 39 to 40 An A-MPDU configuration according to an embodiment of the present invention is shown.

[0299] As described above, the wireless communication terminal can aggregate the A-MPDU by combining an A-MPDU subframe including an MPDU delimiter field in which the EOF subfield is 1 and the MPDU length subfield is not 0 and an A-MPDU subframe including an MPDU delimiter field in which the EOF subfield is 0 and the MPDU length subfield is not 0. In addition, the wireless communication terminal can non-continuously aggregate A-MPDU subframes having the same TID to generate a multi-TID A-MPDU. When the EOF subfield of the MPDU delimiter field is 1 and the MPDU length subfield is not 0, the multi-TID A-MPDU receiver can ACK the MPDU corresponding to the MPDU delimiter field using the per-AIDTID information field in which the block Ack starting sequence control field and the block Ack bitmap field block are omitted. In addition, when the EOF subfield of the MPDU delimiter field is 0 and the MPDU length subfield is not 0, the multi-TID A-MPDU receiver can ACK the MPDU corresponding to the MPDU delimiter field using the per-AID TID information field including both the Block Ack starting sequence control field and the Block Ack bitmap field. For a valid multi-STA Block Ack frame configuration, when the multi-TID A-MPDU transmitter generates a multi-TID A-MPDU, the multi-TID A-MPDU transmitter can limit the number of MPDUs corresponding to the TID requesting an ACK other than the Block Ack to one MPDU per TID. Specifically, when the multi-TID A-MPDU transmitter aggregates the multi-TID A-MPDU, the multi-TID A-MPDU transmitter can add the MPDU corresponding to the MPDU delimiter field to the multi-TID A-MPDU, where the EOF subfield is 1 and the MPDU length subfield is not 0, and then may not add the MPDU having the same TID as the TID of the corresponding MPDU to the multi-TID A-MPDU.

[0300] In addition, when the MPDU included in any one A-MPDU subframe corresponds to a specific TID among the MPDUs included in the multi-TID A-MPDU, the multi-TID A-MPDU transmitter may set the EOF subfield of the A-MPDU subframe to 1. When the MPDU included in any one A-MPDU subframe is only one MPDU corresponding to a specific TID in which the value of the MPDU length field is not 0 among the MPDUs included in the multi-TID A-MPDU, the multi-TID A-MPDU transmitter may set the EOF subfield of the A-MPDU subframe to 1. In addition, when the MPDU included in any one A-MPDU subframe does not correspond to a specific TID among the MPDUs included in the multi-TID A-MPDU, the multi-TID A-MPDU transmitter may set the EOF subfield of the A-MPDU subframe to 0. When the MPDU included in any one A-MPDU subframe is not only one MPDU corresponding to a specific TID in which the value of the MPDU length field is not 0 among the MPDUs included in the multi-TID A-MPDU, the multi-TID A-MPDU transmitter may set the EOF subfield of the A-MPDU subframe to 0.

[0301] In a specific embodiment, when the multi-TID A-MPDU transmitter uses a PPDU of a predetermined format for multi-TID A-MPDU transmission, the multi-TID A-MPDU transmitter may set the EOF subfield according to the embodiment. As described above. For example, when the multi-TID A-MPDU transmitter uses a non-legacy PPDU for transmission of multi-TID A-MPDU, the multi-TID A-MPDU transmitter may set the EOF subfield according to the above embodiment. In this case, the non-legacy PPDU may refer to Fig.28 Describes the PPDU format.

[0302] The multi-TID A-MPDU receiver may generate a multi-STA block Ack frame as follows. When the multi-TID A-MPDU receiver receives all MPDUs corresponding to the MPDU delimiter field in which the EOF subfield is 0 and the MPDU length subfield is not 0, the multi-TID A-MPDU receiver may determine that all MPDUs in the multi-TID A-MPDU requesting block Ack are received. In addition, when the EOF subfield of the MPDU delimiter field corresponding to all MPDUs not received by the multi-TID A-MPDU receiver is 1 and the MPDU length subfield is not 0, the multi-TID A-MPDU receiver may determine that all MPDUs including the request block Ack in the multi-TID A-MPDU are received. When the EOF subfield of the MPDU delimiter field corresponding to all MPDUs not received by the multi-TID A-MPDU receiver is 1, the multi-TID A-MPDU receiver may determine that all MPDUs including the request block Ack in the multi-TID A-MPDU are received.

[0303] According to the following embodiment, the multi-TID A-MPDU receiver may determine that the EOF subfield of the MPDU delimiter field corresponding to the non-received MPDU is 1. In the A-MPDU, when the A-MPDU subframe in which the EOF subfield is set to 0 is limited to not be located after the A-MPDU subframe in which the EOF subfield is set to 1, the multi-TID A-MPDU receiver may determine that the EOF subfield of the MPDU delimiter field corresponding to the non-received MPDU is 1 according to the following embodiment. When the multi-TID A-MPDU receiver does not receive the MPDU included in the A-MPDU subframe located after the A-MPDU subframe including the MPDU delimiter field in which the EOF subfield is 1, the multi-TID A-MPDU receiver may determine that the MPDU corresponding to the MPDU delimiter field in which the EOF subfield is 1 is not received. In another specific embodiment, when the multi-TID A-MPDU receiver receives the MPDU delimiter field and does not receive the MPDU corresponding to the MPDU delimiter field, the multi-TID A-MPDU receiver may check the value of the EOF subfield of the MPDU delimiter field and determine whether the multi-TID A-MPDU receiver has not received the MPDU corresponding to the MPDU delimiter field whose EOF subfield is 1.

[0304] Receiving all MPDUs included in the multi-TID A-MPDU and requesting a Block Ack may mean receiving all MPDUs having a TID corresponding to an MPDU in which the EOF subfield is 0 and the MPDU length subfield is not 0 and included in the multi-TID A-MPDU.

[0305] When the multi-TID A-MPDU receiver receives all MPDUs included in the multi-TID A-MPDU and requests a Block Ack, the multi-TID A-MPDU receiver may ACK using the Per AID TID Information field in which the Block Ack Starting Sequence Control field and the Block Ack Bitmap field are omitted, with respect to the MPDU corresponding to the MPDU delimiter field in which the EDU subfield is 0 and the MPDU Length subfield is not 0. Specifically, the multi-TID A-MPDU receiver may ACK using the Per AID TID Information field in which the Ack Type subfield is set to 1, with respect to the MPDU corresponding to the MPDU delimiter field in which the EDU subfield is 0 and the MPDU Length subfield is not 0. In these embodiments, the multi-TID A-MPDU receiver may set the TID subfield of the Per AID TID Information field to the TID of the received MPDU. In a specific embodiment, the multi-TID A-MPDU receiver may send a multi-STA Block Ack frame to the multi-TID A-MPDU transmitter, indicating that the multi-TID A-MPDU receiver has received all MPDUs of the TID indicated by the TID subfield of the Per AID TID Information field, and includes a multi-STA A Block Ack frame including the Per AID TID Information in which the Block Ack Starting Sequence Control subfield and the Block Ack Bitmap subfield are omitted. In this case, the Per AID TID Information field may also include an indicator indicating that all MPDUs of the TID indicated by the TID subfield of the Per AID TID Information field are received.

[0306] The multi-TID A-MPDU receiver sends the generated multi-STA Block Ack frame to the multi-TID A-MPDU transmitter. When the value of the TID subfield of the per-AID TID information field is 0 to 7 and the value of the Ack type subfield is 1, the multi-TID transmitter may determine that the multi-STA Block Ack frame including the per-AID TID information field is included in the multi-TID A-MPDU requesting the multi-STA Block Ack frame, and the multi-TID receiver receives a single MPDU or all MPDUs corresponding to the TID indicated by the TID subfield.

[0307] exist Fig.39In an embodiment of the present invention, the MPDU that the multi-TID A-MPDU receiver has not received is an MPDU corresponding to an MPDU delimiter field in which the EOF subfield is 1 and the MPDU length subfield is not 0. Therefore, with respect to an MPDU corresponding to an MPDU delimiter field in which the EOF subfield is 0 and the MPDU length subfield is not 0, the multi-TID A-MPDU receiver performs an ACK using the per-AID TID information field, omitting the Block Ack Starting Sequence Control field and the Block Ack Bitmap field in the per-AID TID information field. Specifically, the multi-TID A-MPDU receiver may send a multi-STAA Block Ack including a Block Ack Starting Sequence Control field and a per-AID TID information field to the multi-TID A-MPDU transmitter, wherein the Block Ack Bitmap field is omitted.

[0308] exist Fig.40 In an embodiment of the present invention, an A-MPDU subframe in which the EOF subfield is set to 0 in the A-MPDU is restricted to not be located after an A-MPDU subframe in which the EOF subfield is set to 1. The multi-TID A-MPDU receiver does not receive the MPDU delimiter field corresponding to the unreceived MPDU. Because the value of the EOF subfield of the MPDU delimiter field corresponding to the MPDU located before the unreceived MPDU is 1, the multi-TID A-MPDU receiver can determine that the value of the EOF subfield of the unreceived MPDU delimiter is 1. Therefore, the multi-TID A-MPDU receiver can determine that the multi-TID A-MPDU receiver receives all MPDUs corresponding to the MPDU delimiter field in which the EDU subfield is 0 and the MPDU length subfield is not 0. With respect to the MPDU corresponding to the MPDU Delimiter field in which the EOF subfield is 0 and the MPDU Length subfield is not 0, the multi-TID A-MPDU receiver performs ACK using the per-AID TID Information field, omitting the Block Ack Starting Sequence Control field and the Block Ack Bitmap field in the per-AID TID Information field. Specifically, the multi-TID A-MPDU receiver may send a multi-STA Block Ack including the Block Ack Starting Sequence Control field and the per-AID TID Information field in which the Block Ack Bitmap field is omitted to the multi-TID A-MPDU transmitter.

[0309] Fig.41 The operation of the wireless communication terminal according to the embodiment of the present invention is shown.

[0310] The wireless communication terminal receives a trigger frame for triggering random access (S4101). The wireless communication terminal performs random access based on the trigger frame (S4103). In this case, the wireless communication terminal can perform random access according to the above OBO process. Specifically, according to the reference Figures 6 to 26According to the described embodiments, the wireless communication terminal may perform random access.

[0311] The wireless communication terminal may set an integer selected from 0 to a value equal to or less than the OFDMA contention window (OCW) as a counter for random access. In this case, the counter for random access may be the above-mentioned OBO counter. In addition, when the wireless communication terminal attempts random access for the first time, the wireless communication terminal receives OBO-related parameters signaled by the base station wireless communication terminal, or the wireless communication terminal successfully transmits through random access, the wireless communication terminal may initialize the OBO process. The initialization of the OBO process may include at least one of the initialization of the counter for random access and the initialization of the OCW. In addition, when the wireless communication terminal initializes the OCW, the wireless communication terminal may set the OCW to OCWmin. When the transmission of random access by the wireless communication terminal fails, the wireless communication terminal may update the value of the OCW to (2×OCW+1). In this case, the wireless communication terminal selects a random integer in the updated OCW and sets the selected integer as the counter for random access. In addition, when the value of the OCW reaches OCWmax, the wireless communication terminal may maintain the OCW to OCWmax even if the transmission of random access by the wireless communication terminal fails.

[0312] The trigger frame may indicate random access using one or more RUs allocated for random access. Specifically, the trigger frame may indicate allocation of one or more RUs for random access. In this case, the wireless communication terminal may decrement the value of the counter for random access based on the one or more RUs allocated for random access. When the trigger frame indicates uplink transmission of the wireless communication terminal, the wireless communication terminal may not decrement the value of the counter based on the trigger frame. The specific operation of the wireless communication terminal may be the same as that of the reference Fig.26 The operation in the described embodiments is the same.

[0313] In this case, as described above, the RU is a group of multiple subcarriers that can be used for uplink transmission and downlink transmission.

[0314] The wireless communication terminal may decrement the value of the counter for random access based on the capability of the wireless communication terminal and one or more RUs allocated for random access. When the value of the counter for random access is 0 or reaches 0, the wireless communication terminal may randomly select one or more RUs allocated for random access.

[0315] The wireless communication terminal may perform a random access operation according to the capability of the wireless communication terminal. In this case, the wireless communication terminal may operate as follows.

[0316] The wireless communication terminal may decrement the value of the counter for random access by the number of RUs through which the wireless communication terminal can send a TB PPDU according to the capability of the wireless communication terminal among one or more RUs allocated for random access. The capability of the wireless communication terminal may include a capability related to a bandwidth through which the wireless communication terminal can perform transmission. In addition, the capability of the wireless communication terminal may include a capability of a length of a padding field included in a TB PPDU. In addition, the capability of the wireless communication terminal may include a capability of a modulation and coding scheme for which the wireless communication terminal can perform transmission. The capability of the wireless communication terminal may include a capability of the wireless communication terminal related to at least one of dual carrier modulation (DCM), the number of spatial streams, the length of a guard interval (GI), a long training field (LTF) type, a spatial block coding (STBC), and a transmission power.

[0317] When the value of the counter for random access is 0 or reaches 0, the wireless communication terminal may randomly select any one of the RUs allocated for random access, and may transmit the TB PPDU according to the capability of the wireless communication terminal. When there is no RU through which the wireless communication terminal can transmit the TB PPDU among one or more RUs allocated for random access, the wireless communication terminal may maintain the counter for random access at 0. Operations related to the capability of the wireless communication terminal may be related to Figures 14 to 21 The operation of the wireless communication terminal in the embodiment is the same.

[0318] The wireless communication terminal may be a wireless communication terminal that is not associated with the base station wireless communication terminal that sends the trigger frame. In this case, the wireless communication terminal may operate as follows.

[0319] The wireless communication terminal may set the OCW minimum value as a parameter indicating the minimum value of the OCW to a predetermined value as a default value of the OCW minimum value, and set the OCW maximum value as a parameter indicating the maximum value of the OCW to a predetermined value as a default value of the OCW maximum value. In this case, the value predetermined as the default value of the OCW minimum value and the value predetermined as the default value of the OCW maximum value may not be a value specified by the base station wireless communication terminal. As described above, the OCW minimum value may be the OCWmin described above. In addition, the OCW maximum value may be the OCWmax described above.

[0320] When the wireless communication terminal communicates with the base station wireless communication terminal that sends the trigger frame and another base station wireless communication terminal, the wireless communication terminal can initialize parameters for random access to another wireless communication terminal. The parameters for random access may include a counter for random access, an OCW minimum value, and an OCW maximum value, which are parameters indicating the maximum value of the OCW. When the wireless communication terminal communicates with the base station wireless communication terminal that sends the trigger frame, the wireless communication terminal can set the OCW minimum value and the OCW maximum value according to the information received from the base station wireless communication terminal that sends the trigger frame, and when the wireless communication terminal communicates with another base station wireless communication terminal, the wireless communication terminal can set the OCW minimum value and the OCW maximum value according to the information received from other base station wireless communication terminals. In this case, the information received from the base station wireless communication terminal that sends the trigger frame or the base station wireless communication terminal through wireless communication may be information about OBO parameters. Specifically, the information about OBO parameters may be the above-mentioned UORA parameter set element. The wireless communication terminal may maintain OBO-related parameters and OBO processes for each base station wireless communication terminal. In a specific embodiment, the wireless communication terminal may set OBO-related parameters for each base station wireless communication terminal. Specifically, the wireless communication terminal may set OBO-related parameters for each base station wireless communication terminal based on information about OBO-related parameters received from each base station wireless communication terminal. The specific operation of the wireless communication terminal not associated with the base station wireless communication terminal can be referred to in Figure 21 to Figure 25 The same as in the described embodiment.

[0321] The wireless communication terminal may be a wireless communication terminal associated with the base station wireless communication terminal that sends the trigger frame. In addition, the base station wireless communication terminal that sends the trigger frame may belong to a multi-BSSID set. In this case, the wireless communication terminal may operate as follows.

[0322] The OCW minimum value and the OCW maximum value may be set based on information received from other base station wireless communication terminals belonging to the multi-BSSID set to which the base station wireless communication terminal that sends the trigger frame belongs. In this case, the other base station wireless communication terminal may be a base station wireless communication terminal that operates a BSS corresponding to the sent BSSID of the multi-BSSID set. In addition, the wireless communication terminal may not decrement the value of the counter based on the trigger frame sent from the other base station wireless communication terminal. The other base station wireless communication terminal may be a base station wireless communication terminal that operates a BSS corresponding to the sent BSSID of the multi-BSSID set. The information received from the other base station wireless communication terminals may not be information indicated only in the signaling field allocated for the BSS including the wireless communication terminal. Specifically, the signaling field allocated only for the BSS including the wireless communication terminal may indicate the above-mentioned unsent profile. In this case, the information may be the above-mentioned UORA parameter set element. When using a multiple BSSID set, the specific operation of the wireless communication terminal may be different from the reference. Figures 11 to 13 The specific operations in the described embodiments are the same.

[0323] The wireless communication terminal may attempt to use the selected RU to perform transmission to the base station wireless communication terminal. In this case, the wireless communication terminal may determine whether the selected RU is idle, and when the selected RU is idle, the pending frame of the base station wireless communication terminal may be sent to the base station wireless communication terminal through the selected RU. In addition, when the wireless communication terminal determines that the corresponding RU is busy through any one of physical carrier sensing or virtual carrier sensing, the wireless communication terminal determines that the corresponding RU is busy. Physical carrier sensing may include idle channel assessment (CCA). When it is determined that the RU selected by the wireless communication terminal is busy, the wireless communication terminal may maintain the OBO counter at 0 without sending the pending frame to the base station wireless communication.

[0324] 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. In addition, although the method, device and system 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 using a computer system with a general hardware architecture.

[0325] The features, structures and effects described in the above-described 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 combination and improvement is included in the scope of the present invention.

[0326] Although the present invention is mainly described based on the above embodiments but not limited thereto, it will be appreciated by those skilled in the art that various changes and improvements may be made without departing from the spirit and scope of the present invention. For example, each component specifically shown in the embodiment may be modified and implemented. It should be understood that the differences associated with such modifications and applications are included within the scope of the present invention as defined in the appended claims.

Claims

1. A wireless communication terminal for wirelessly communicating with a base station wireless communication terminal, the wireless communication terminal comprising: Transceiver; and processor, Wherein, the processor is configured to: when the wireless communication terminal is associated with the base station wireless communication terminal operating a BSS corresponding to an untransmitted BSSID of a multiple basic service set identifier (BSSID) set, setting an OCW minimum value as a parameter indicating a minimum value of an orthogonal frequency division multiple access (OFDMA) contention window (OCW) and an OCW maximum value as a parameter indicating a maximum value of the OCW according to a UL OFDMA-based random access (UORA) parameter set from a different base station wireless communication terminal operating a BSS corresponding to a transmitted BSSID of the multiple BSSID set, setting an integer selected from a range of 0 to a value equal to or smaller than the OCW as a counter for random access, When the wireless communication terminal receives, using the transceiver, from the base station wireless communication terminal a trigger frame for triggering random access using the first one or more resource units RU allocated for the random access, the value of the counter is decremented by the number of RUs among the first one or more RUs allocated for the random access through which the wireless communication terminal can send a trigger-based physical layer protocol data unit PPDU according to the capability of the wireless communication terminal, When the wireless communication terminal receives a trigger frame for triggering random access using the second one or more RUs allocated for the random access from the different base station wireless communication terminal, the value of the counter is not decremented based on the trigger frame sent from the different base station wireless communication terminal, When the value of the counter is 0 or reaches 0, randomly selecting any one of the first one or more RUs allocated for the random access, through which the wireless communication terminal can send a triggered PPDU according to the capability of the wireless communication terminal, and attempting transmission to the base station wireless communication terminal using the selected RU, The RU is a group of multiple subcarriers that can be used for uplink transmission and downlink transmission.

2. The wireless communication terminal according to claim 1, wherein: The capabilities of the wireless communication terminal include capabilities related to a bandwidth through which the wireless communication terminal can perform transmissions.

3. The wireless communication terminal according to claim 1, wherein: The capability of the wireless communication terminal includes a capability related to a length of a padding field included in the trigger-based PPDU.

4. A method for operating a wireless communication terminal for wireless communication with a base station wireless communication terminal, the method comprising: when the wireless communication terminal is associated with the base station wireless communication terminal operating a BSS corresponding to an untransmitted BSSID of a multiple basic service set identifier (BSSID) set, setting an OCW minimum value as a parameter indicating a minimum value of an orthogonal frequency division multiple access (OFDMA) contention window (OCW) and an OCW maximum value as a parameter indicating a maximum value of the OCW according to a UL OFDMA-based random access (UORA) parameter set from a different base station wireless communication terminal operating a BSS corresponding to a transmitted BSSID of the multiple BSSID set, setting an integer selected from a range of 0 to a value equal to or smaller than the OCW as a counter for random access, When the wireless communication terminal receives a trigger frame for triggering random access using the first one or more resource units RU allocated for the random access from the base station wireless communication terminal, the value of the counter is decremented by the number of RUs among the first one or more RUs allocated for the random access through which the wireless communication terminal can send a trigger-based physical layer protocol data unit PPDU according to the capability of the wireless communication terminal, When the wireless communication terminal receives a trigger frame for triggering random access using the second one or more RUs allocated for the random access from the different base station wireless communication terminal, the value of the counter is not decremented based on the trigger frame sent from the different base station wireless communication terminal, When the value of the counter is 0 or reaches 0, randomly selecting any one of the first one or more RUs allocated for the random access, through which the wireless communication terminal can send a triggered PPDU according to the capability of the wireless communication terminal, and attempting transmission to the base station wireless communication terminal using the selected RU, The RU is a group of multiple subcarriers that can be used for OFDM communication.

5. The method according to claim 4, wherein: The capabilities of the wireless communication terminal include capabilities related to a bandwidth through which the wireless communication terminal can perform transmissions.

6. The method according to claim 4, wherein: The capability of the wireless communication terminal includes a capability related to a length of a padding field included in the trigger-based PPDU.

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