Wireless communication method and wireless communication terminal using the same

Abstract

A wireless communication method and a wireless communication terminal using the same are disclosed. The wireless communication terminal includes a transceiver and a processor, the processor being used to process a wireless signal received by the transceiver or a wireless signal to be sent by the transceiver. The processor accesses a channel according to the priority of data to be sent by the wireless communication terminal to a basic communication terminal.

Description

[0001] This application is a divisional application of the patent application with application number 201780054732.0 (PCT / KR2017 / 009841) filed on March 6, 2019 with the international application date of September 7, 2017 and the invention name of “Wireless communication method using enhanced distributed channel access, and wireless communication terminal using the same”. Technical Field

[0002] The present invention relates to a wireless communication method and a wireless communication terminal using enhanced distributed channel 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, IEEE802.11ad 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 base station terminals, 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 a plurality of terminals and a base station terminal. 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 enhanced distributed channel access.

[0011] Technical Solution

[0012] According to an embodiment of the present invention, a wireless communication terminal for wirelessly communicating with a basic wireless communication terminal includes: a transceiver; and a processor for processing a radio signal received by the transceiver or a radio signal sent by the transceiver. The processor is configured to access a channel according to the priority of data to be sent by the wireless communication terminal to the basic communication terminal.

[0013] The processor may be configured to switch a parameter set as a parameter set for channel access from a first parameter set to a second parameter set based on whether the base wireless communication terminal triggers multi-user uplink transmission participation of the wireless communication terminal.

[0014] The processor can be configured to send a triggered physical layer protocol data unit (PPDU) to the basic wireless communication terminal using the transceiver, set a second parameter set timer according to the immediate response reception based on whether an immediate response to a MAC protocol data unit (MPDU) included in the triggered PPDU is received, and terminate the application of the second parameter set when the second parameter set timer expires.

[0015] The processor may be configured to set a second parameter set timer upon completion of receipt of the immediate response.

[0016] The processor may be configured to set a second parameter set timer for the access category for which the MPDU for which the immediate response was received.

[0017] The processor may be configured to determine when to set the second parameter set timer according to a type of response requested by the MPDU included in the trigger-based PPDU.

[0018] When the MPDU included in the trigger-based PPDU does not request ACK, the processor may be configured to set a second parameter set timer at the end of transmission of the trigger-based PPDU.

[0019] The MPDU included in the trigger-based PPDU may be a QoS data frame.

[0020] The processor may be configured to receive a beacon frame from the infrastructure wireless communication terminal, and obtain information indicating a period of the second parameter set timer from the beacon frame.

[0021] When the parameter set is switched from the first parameter set to the second parameter set, the processor may be configured to set a second parameter set timer. Specifically, when the MPDU included in the trigger-based PPDU does not request ACK, the processor may be configured to switch the parameter set from the first parameter set to the second parameter and set the second parameter set timer at the end of the trigger-based PPDU transmission.

[0022] The processor may be configured to calculate a random integer value in a contention window (CW), set a backoff timer based on the random integer value, and access the channel based on the backoff timer and a predetermined time slot time. In this case, the parameter set may include a minimum value (CWmin) of the CW and a maximum value (CWmax) of the CW.

[0023] Furthermore, when the value of CW according to the priority of the service is greater than a maximum value (CWmax) of CW, the processor may be configured to set the value of CW to CWmax.

[0024] The processor can be configured to operate multiple queues classified according to the access category of the data stored in the queues, and perform a backoff process of the access channel based on the time corresponding to the backoff timer of each of the multiple queues, and when there is no data stored in the queue and the backoff timer corresponding to the queue is 0, no operation is performed at the time slot boundary of the backoff timer, wherein the backoff timer can be set according to a random integer value calculated within a contention window (CW) and can be reduced when the channel is idle within a predetermined time slot time.

[0025] When there is no data stored in the queue and the backoff timer corresponding to the queue is 0, the processor may be configured to maintain the backoff timer at 0.

[0026] According to an embodiment of the present invention, an operation method of a wireless communication terminal for wirelessly communicating with an infrastructure wireless communication terminal includes: accessing a channel according to a priority of data to be sent to the infrastructure wireless communication terminal; and sending data through the channel.

[0027] Access to the channel may include: switching a parameter set used for channel access from a first parameter set to a second parameter set based on whether the basic wireless communication terminal triggers the wireless communication terminal's participation in multi-user uplink transmission; and accessing the channel using the second parameter set based on the priority of the service to be sent by the wireless communication terminal to the basic communication terminal.

[0028] The method may also include sending a triggered PPDU to the basic wireless communication terminal using a transceiver, wherein switching from the first parameter set to the second parameter set may include: setting a second parameter set timer according to the immediate response reception based on whether an immediate response to a MAC protocol data unit (MPDU) included in the triggered PPDU is received; and terminating the application of the second parameter set when the second parameter set timer expires.

[0029] The setting of the second parameter set timer may include setting the second parameter set timer at the end of receiving the immediate response.

[0030] The setting of the second parameter set timer may include setting the second parameter set timer for the access category for which the MPDU for the immediate response was received.

[0031] The setting of the second parameter set timer may determine when to set the second parameter set timer according to the type of response requested by the MPDU included in the triggered PPDU.

[0032] The setting of the second parameter set timer may include, when the MPDU included in the triggered PPDU does not request ACK, setting the second parameter set timer when transmission of the triggered PPDU ends.

[0033] Beneficial Effects

[0034] Embodiments of the present invention provide a wireless communication method using enhanced distributed channel access and a wireless communication terminal using the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A wireless LAN system according to an embodiment of the present invention is shown.

[0036] Figure 2 A wireless LAN system according to another embodiment of the present invention is shown.

[0037] Figure 3 A block diagram illustrating a configuration of a station according to an embodiment of the inventive concept is shown.

[0038] Figure 4 A block diagram illustrating a configuration of an access point according to an embodiment of the present invention is shown.

[0039] 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.

[0040] Figure 6 It is shown that the wireless communication terminal according to an embodiment of the present invention adjusts EDCA parameters according to UL MU transmission.

[0041] Figure 7A method for applying a MU EDCA parameter set by a wireless communication terminal according to an embodiment of the present invention is shown.

[0042] Figure 8 A method for aggregating multi-TID A-MPDUs by a wireless communication terminal according to an embodiment of the present invention is shown.

[0043] Fig. 9 An operation of a wireless communication terminal according to an embodiment of the present invention receiving information about a MU EDCA parameter set from a base wireless communication terminal and applying the information about the MU EDCA parameter set is shown.

[0044] Fig.10 The operation of a basic wireless communication terminal transmitting a BSR through a QoS control field according to an embodiment of the present invention is described.

[0045] Fig.11 An operation of a wireless communication terminal according to another embodiment of the present invention receiving information about a MU EDCA parameter set from a base wireless communication terminal and applying the information about the MU EDCA parameter set is shown.

[0046] Fig.12 An operation of a wireless communication terminal according to another embodiment of the present invention obtaining information about a MU EDCA parameter set from a trigger frame and applying the information about the MU EDCA parameter set is shown.

[0047] Fig.13 An operation of a wireless communication terminal according to another embodiment of the present invention obtaining information on a MU EDCA parameter set from a target wake-up time element and applying the information on the MU EDCA parameter set is shown.

[0048] Fig.14 The operation of the wireless communication terminal terminating the application of MU EDCA parameters according to the embodiment of the present invention is shown.

[0049] Fig.15 An operation of a wireless communication terminal terminating the application of MU EDCA parameters according to another embodiment of the present invention is shown.

[0050] Fig.16 The operation of a wireless communication terminal applying MU EDCA parameters according to another embodiment of the present invention is shown.

[0051] Fig.17 An A-MPDU generated by a wireless communication terminal according to an embodiment of the present invention and a response type for the corresponding A-MPDU are shown.

[0052] Fig.18 The operation of a wireless communication terminal applying MU EDCA parameters according to another embodiment of the present invention is shown.

[0053] Fig.19 The operation of a wireless communication terminal applying a MU EDCA parameter set according to an embodiment of the present invention is shown.

[0054] Fig. 20 An operation of changing a CW value while changing an EDCA parameter set at a wireless communication terminal according to an embodiment of the present invention is shown.

[0055] Fig.21 An operation of changing a CW value while changing an EDCA parameter set at a wireless communication terminal according to an embodiment of the present invention is shown.

[0056] Fig. 22 A specific format of a MU EDCA parameter set element according to an embodiment of the present invention is shown.

[0057] Fig.23 A specific format of a MU EDCA parameter set element according to another embodiment of the present invention is shown.

[0058] Fig.24 An EDCA operation after UL MU transmission of a wireless communication terminal according to an embodiment of the present invention is shown.

[0059] Fig.25 The operation of the wireless communication terminal when the EDCA queue of the wireless communication terminal according to the embodiment of the present invention is empty and the backoff timer is 0 is shown.

[0060] Fig.26 An operation of a wireless communication terminal when an EDCA queue of the wireless communication terminal according to another embodiment of the present invention is empty and the backoff timer is 0 is shown.

[0061] Fig. 27 An operation of a wireless communication terminal when an EDCA queue of the wireless communication terminal according to another embodiment of the present invention is empty and the backoff timer is 0 is shown.

[0062] Fig.28 The operation of the wireless communication terminal according to the embodiment of the present invention is shown. DETAILED DESCRIPTION

[0063] 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.

[0064] 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.

[0065] This application claims priority to and the benefit of Korean Patent Applications Nos. 10-2016-0114822 (September 7, 2016), 10-2016-0116877 (September 10, 2016), 10-2016-0116965 (September 12, 2016), 10-2016-0117898 (September 13, 2016), 10-2016-0122488 (September 23, 2016), 10-2016-0147189 (November 6, 2016), and 10-2017-0022227 (February 20, 2017) 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.

[0066] 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.

[0067] 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.

[0068] A station (STA) is a predetermined device including a media access control (MAC) following the procedures of the IEEE 802.11 standard and a physical layer interface for a wireless medium, and in a broad sense includes a non-access point (non-AP) station and an access point (AP). 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.

[0069] 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.

[0070] 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).

[0071] 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.

[0072] 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.

[0073] Figure 3 is a block diagram illustrating a configuration of a station 100 according to an embodiment of the present invention.

[0074] like Figure 3As 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 .

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] Figure 4 is a block diagram illustrating a configuration of an AP 200 according to an embodiment of the present invention.

[0081] 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.

[0082] 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.

[0083] 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 radio signal transmission / reception of the AP 200 according to the first embodiment of the present invention. Its detailed embodiment will be described below.

[0084] Figure 5 is a diagram schematically illustrating a process in which a STA sets up a link with an AP.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] The basic wireless communication terminal may be a wireless communication terminal for allocating and scheduling media resources for communicating with multiple wireless communication terminals. Specifically, the basic wireless communication terminal may be used as a cell coordinator. In a specific embodiment, the basic wireless communication terminal may be a wireless communication terminal that allocates and schedules communication media resources in an independent network (e.g., an ad-hoc network) that is not connected to an external distribution service.

[0090] In a frequency band commonly used by various wireless communication devices such as an unlicensed frequency band, a wireless communication terminal can access a channel through a contention process. Specifically, if the channel to be accessed by the wireless communication terminal is idle within a predetermined time, the wireless communication terminal starts a backoff process. During the backoff process, the wireless communication terminal obtains a random integer value in a contention window (CW) and sets the random integer value as a backoff timer. If the corresponding channel is idle during a predetermined time slot, the wireless communication terminal reduces the backoff timer. If the value of the backoff timer is 0, the wireless communication terminal accesses the corresponding channel. At this time, if the corresponding channel is busy, the wireless communication terminal stops the backoff process. If the channel to be accessed by the wireless communication terminal is idle within a predetermined time, the wireless communication terminal resumes the backoff process again.

[0091] In addition, the wireless communication terminal can access the channel according to the priority of the data to be sent. Specifically, the wireless communication terminal can use the CW determined according to the priority of the data to be sent. At this time, the minimum value CWmin and the maximum value CWmax of the CW are determined according to the priority of the data to be sent by the wireless communication terminal. In addition, the wireless communication terminal wants to wait for the scheduled time to start the backoff process according to the priority of the data to be sent by the wireless communication terminal. In addition, the wireless communication terminal can wait for the time specified according to the priority of the data to be sent, and then start the backoff process. The specified time according to the priority is called the arbitration interframe space (AIFS). This operation is called enhanced distributed channel access (EDCA). In addition, the priority of the data can be determined according to the access category (AC).

[0092] The basic wireless communication terminal can trigger uplink transmission from one or more wireless communication terminals to the basic wireless communication terminal. At this time, one or more wireless communication terminals can perform uplink transmission to the basic wireless communication terminal using orthogonal frequency division multiple access (OFDMA). In addition, the basic wireless communication terminal sends trigger information to one or more wireless communication terminals through a trigger frame or a MAC header to trigger uplink transmission of the basic wireless communication terminal for one or more wireless communication terminals. At this time, the basic wireless communication terminal accesses the channel for uplink transmission of one or more wireless communication terminals. In addition, one or more wireless communication terminals access the channel for uplink transmission of each of one or more wireless communication terminals. Therefore, when the basic wireless communication terminal schedules uplink transmission of one or more wireless communication terminals for uplink transmission, the uplink transmission of one or more wireless communication terminals has a higher priority than the transmission of other wireless communication terminals with the same priority. In addition, because the basic wireless communication terminal and one or more wireless communication terminals access the channel for the same transmission at the same time, the channel access efficiency may be reduced. Therefore, when scheduling uplink multi-user (UL-MU) transmission, it is necessary to adjust the EDCA parameter value.

[0093] Figure 6 It is shown that the wireless communication terminal according to an embodiment of the present invention adjusts EDCA parameters according to UL MU transmission.

[0094] A wireless communication terminal scheduled for UL MU transmission may use a channel access method to ensure successful channel access with a lower probability than when it is not scheduled for UL MU transmission. Specifically, a wireless communication terminal scheduled for UL MU transmission may use a separate EDCA parameter set. In a specific embodiment, a wireless communication terminal scheduled for UL MU transmission may use an EDCA parameter set that attempts to access a channel with a lower probability than the probability of a previously used EDCA parameter set in a channel access for sending the same data. At this time, the EDCA parameter set is a parameter set used in an EDCA operation according to the priority of data sent by the wireless communication terminal. Specifically, the EDCA parameter set may include a parameter of a CW. At this time, the parameter of the CW may include at least one of CWmin and CWmax. In addition, the EDCA parameter set may include a parameter value related to a predetermined time for the wireless communication terminal to wait for the start of the backoff process. At this time, the predetermined time may be the above-mentioned AIFS. For ease of description, a separate EDCA parameter set used by a wireless communication terminal scheduled for UL MU transmission is referred to as a MU EDCA parameter set.

[0095] As in Figure 7 As in the embodiment of the present invention, when the channel to be accessed is continuously idle for an AIFS period longer than a normal AIFS period for waiting for transmission of corresponding data, the wireless communication terminal applying the MU EDCA parameter set accesses the channel. When the corresponding channel is idle during the AIFS period corresponding to the MU EDCA parameter set, the wireless communication terminal starts a backoff process for the corresponding channel.

[0096] The basic wireless communication terminal may send information about the MU EDCA parameter set to the wireless communication terminal scheduled for UL MU transmission. Specifically, the basic wireless communication terminal may send a MU EDCA parameter element including information about the MU EDCA parameter set to the wireless communication terminal scheduled for UL MU transmission. At this time, the basic wireless communication terminal may use a beacon frame to send the MU EDCA parameter element. Figures 7 to 11 The specific method of switching the EDCA parameter set is described in detail.

[0097] Figure 7 A method for a wireless communication terminal to apply a MU EDCA parameter set according to an embodiment of the present invention is shown.

[0098] The wireless communication terminal may determine whether to apply the MU EDCA parameter set by each AC. Specifically, the wireless communication terminal may determine whether to apply the MU EDCA parameter set by each AC based on UL MU transmission. In a specific embodiment, the wireless communication terminal may apply the MU EDCA parameter set to data transmission corresponding to the AC scheduled for UL MU transmission. This is because if the MU EDCA parameter set is applied to an AC that does not correspond to a UL MU transmission target, channel access fairness may be reduced.

[0099] exist Figure 7 In an embodiment of the present invention, the wireless communication terminal applies the MU EDCA parameter set. At this time, the wireless communication terminal applies the MU EDCA parameter set to some ACs (e.g., BE and BK) indicated by the MU EDCA parameter set. Therefore, in order for the AC to send services corresponding to BE and BK, the wireless communication terminal uses the MU EDCA parameter set to access the channel. At this time, the probability that the wireless communication terminal can start transmission within a predetermined time is lower than the probability when the normal EDCA parameter set is used.

[0100] When the wireless communication terminal determines whether to apply the MU EDCA parameter set to each AC, the wireless communication terminal may guide the AC to which the MU EDCA parameter set is applied to a specific AC to reduce fairness with other terminals. For example, the wireless communication terminal may only induce the data of the AC with a relatively large backoff timer value to be scheduled for UL MU transmission. Therefore, the wireless communication terminal may determine whether to apply the MU EDCA parameter set based on the current channel access waiting state. Specifically, when the wireless communication terminal applies the MU EDCA parameter set, the wireless communication terminal may be adjusted to forcibly apply the MU EDCA parameter set to the main AC with the shortest channel access waiting time. At this time, the channel access waiting time may be determined based on the value of the remaining backoff timer and the AIFS value. Specifically, the channel access waiting time may be the sum of the time corresponding to the backoff timer and the AIFS. When there are multiple wireless communication terminals with the minimum channel access waiting time, the wireless communication terminal may limit the EDCA parameter setting application conditions to forcibly apply the MU EDCA parameter set to multiple ACs.

[0101] Figure 8 A method for aggregating multi-TID A-MPDUs by a wireless communication terminal according to an embodiment of the present invention is shown.

[0102] The wireless communication terminal may aggregate a plurality of MPDUs corresponding to each of a plurality of TIDs and generate an aggregated MAC protocol data unit (A-MPDU). At this time, the A-MPDU may be referred to as a multi-TID A-MPDU. At this time, when the wireless communication terminal intentionally inserts the MPDU of the TID corresponding to the AC with the maximum channel access waiting time into the multi-TID A-MPDU, the transmission fairness between the wireless communication terminals may be reduced. Therefore, the wireless communication terminal may be restricted from sending a multi-TID A-MPDU including an MPDU of the TID corresponding to the AC with the minimum channel access waiting time. At this time, the size of the MPDU of the TID corresponding to the AC with the minimum channel access waiting time included in the multi-TID A-MPDU may be greater than a predetermined size. In addition, when the wireless communication terminal performs UL MU transmission, the wireless communication terminal may be restricted from sending a multi-TID A-MPDU including a TID indicated by the base wireless communication terminal.

[0103] exist Figure 8 The AC with the minimum channel access waiting time among the wireless communication terminals is VO. The wireless communication terminal generates a multi-TID A-MPDU including an MPDU of TID TID1 corresponding to VO. The wireless communication terminal sends the generated multi-TID A-MPDU to the basic wireless communication terminal. At this time, the wireless communication terminal can send a buffer status report (BSR) through the QoS control field of the MPDU included in the multi-TID A-MPDU. Fig.10 This is described in more detail. Through these embodiments, the wireless communication terminal can maintain channel access fairness with other wireless communication terminals.

[0104] As described above, the base wireless communication terminal may send information about the MU EDCA parameter set to the wireless communication terminal. Figures 9 to 11 Describe this.

[0105] Fig. 9 An operation of a wireless communication terminal according to an embodiment of the present invention receiving information about a MU EDCA parameter set from a base wireless communication terminal and applying the information about the MU EDCA parameter set is shown.

[0106] When the wireless communication terminal sends a BSR, the wireless communication terminal can apply the MU EDCA parameter set. Specifically, when the wireless communication terminal sends a BSR, the wireless communication terminal can apply the MU EDCA parameter set to the AC related to the BSR transmission. The AC related to the BSR transmission can be an AC with a buffer status reported through the BSR. In addition, when the wireless communication terminal sends a BSR, the wireless communication terminal can apply the MU EDCA parameter set to all ACs. This is because the basic wireless communication terminal can schedule UL MU transmission based on the BSR sent by the wireless communication terminal. Specifically, when the transmission of the BSR is completed by from, the wireless communication terminal can access the channel by applying the MU EDCA parameter set, such as Fig. 9 The wireless communication terminal may use various methods to send the BSR to the basic wireless communication terminal. Fig.10 Describe this.

[0107] Fig.10 The operation of a basic wireless communication terminal transmitting a BSR through a QoS control field according to an embodiment of the present invention is described.

[0108] The wireless communication terminal can use the QoS control field of the MAC header to send the BSR. In addition, the format of the BA control field can be the same as Fig.10 The format of the embodiment of (a) is the same. Specifically, the wireless communication terminal can use the QoS control field of the MPDU to send the BSR while sending the MPDU including QoS data. In addition, the wireless communication terminal can use the QoS control field of the MPDU to send the BSR while sending the QoS null MPDU (Qos null MPDU) that does not include data. In addition, regardless of the limit on the number of TIDs that can be included in the multi-TID A-MPDU, the wireless communication terminal can insert the QoS null MPDU into the A-MPDU.

[0109] In such Fig.10 In the uplink single user (UL SU) transmission in the embodiment of (b), the wireless communication terminal may use the QoS control field to send the BSR. In addition, in the UL MU transmission triggered by the trigger frame, the wireless communication terminal may use the QoS control field to send the BSR. In addition, the wireless communication terminal receives an A-MPDU from the basic wireless communication terminal, and the wireless communication terminal may use the QoS control field to send the BSR while sending the BA frame for the A-MPDU. In addition, the wireless communication terminal may receive a BSRP, which is a trigger frame for triggering BSR transmission, and the wireless communication terminal may use the QoS control field of the QoS empty MPDU to send the BSR.

[0110] Again, describe Fig. 9 . In another specific embodiment, the wireless communication terminal may apply the MU EDCA parameter set when receiving information about UL MU scheduling from the basic wireless communication terminal. At this time, the information about UL MU scheduling may be information indicating that UL MU transmission is scheduled. In addition, the basic wireless communication terminal may use at least one of a beacon frame and an action frame to send information about UL MU transmission scheduling to the wireless communication terminal. The wireless communication terminal may obtain information about UL MU transmission scheduling from at least one of a beacon frame and an action frame. In this case, the action frame may be a no-ACK action frame that does not require an ACK frame for the action frame. Specifically, the wireless communication terminal receives information about UL MU scheduling from the basic wireless communication terminal and applies the MU EDCA parameter set to the AC indicated by the UL MU scheduling information. In addition, the wireless communication terminal may apply the MU EDCA parameter set to the AC that has a history of sending a BSR within a predetermined period starting from when the information about UL MU scheduling is received. The information about UL MU scheduling may be included in a reserved bit of the HE operation element. In addition, if the beacon frame includes the MU EDCA parameter set, the beacon frame implicitly indicates that UL MU transmission is scheduled. In addition, the field indicating the MU EDCA parameter set may include a field indicating that UL MU transmission is scheduled. Fig. 9 In the embodiment of (b), the wireless communication terminal receives a beacon frame. The wireless communication terminal obtains information about UL MU scheduling from the beacon frame. At this time, the wireless communication terminal applies the MU EDCA parameter set to the AC that transmits the BSR in the period from the reference point to the time when the UL MU scheduling information is received.

[0111] In another specific embodiment, in addition to whether to schedule UL MU transmission, the basic wireless communication terminal may also send specific UL MU transmission scheduling information. Fig.11 Describe this.

[0112] Fig.11 An operation of a wireless communication terminal according to another embodiment of the present invention receiving information about a MU EDCA parameter set from a base wireless communication terminal and applying the information about the MU EDCA parameter set is shown.

[0113] The basic wireless communication terminal may transmit information for identifying a wireless communication terminal for which UL MU transmission is scheduled. The wireless communication terminal may receive information for identifying a wireless communication terminal scheduled for UL MU transmission, and apply a MU EDCA parameter set for information for identifying a wireless communication terminal for scheduling UL MU transmission. Specifically, the basic wireless communication terminal may periodically transmit information for identifying a wireless communication terminal scheduled for UL MU transmission within a predetermined period. At this time, the basic wireless communication terminal may use a beacon frame to transmit information for identifying a wireless communication terminal scheduled for UL MU transmission within a predetermined period. In addition, the basic wireless communication terminal may use a TIM element of a beacon frame to transmit information for identifying a wireless communication terminal scheduled for UL MU transmission. In another specific embodiment, the basic wireless communication terminal may use an element indicating information related to UL MU scheduling to transmit information for identifying a wireless communication terminal scheduled for UL MU transmission. In addition, the basic wireless communication terminal may transmit not only information for identifying a wireless communication terminal scheduled for UL MU transmission, but also information for indicating an AC for UL MU transmission scheduling data. At this time, the information indicating an AC for UL MU transmission scheduling data may indicate all ACs in some cases. In addition, the basic wireless communication terminal may not only send information for identifying the wireless communication terminal scheduled for UL MU transmission, but also send information indicating a time point for triggering UL MU transmission. At this time, the time point for triggering UL MU transmission may indicate a time point for sending trigger information. Specifically, the trigger information may include a trigger frame. In addition, the basic wireless communication terminal may send a backoff timer value for a backoff process for sending trigger information.

[0114] exist Fig.11 In an embodiment, the first station STA1 sends a BSR to the access point AP. The access point AP receives the BSR and schedules uplink transmission of the first station STA1 based on the received BSR. The access point AP sends information about scheduled UL MU transmission using a beacon frame. At this time, the information about the scheduled UL MU transmission may include information for identifying a wireless communication terminal scheduled for UL MU transmission. At this time, the information about the scheduled UL MU transmission may be a bitmap indicating whether an association ID (AID) or a wireless communication terminal corresponding to the AID is scheduled for UL MU transmission. The first station STA1 receives a beacon frame from the access point AP and obtains information about the scheduled UL MU transmission from the beacon frame. When the information about the scheduled UL MU transmission indicates that the first station STA1 is scheduled for UL MU transmission, the first station STA1 applies the MU EDCA parameter set.

[0115] Fig.12An operation of a wireless communication terminal according to another embodiment of the present invention obtaining information about a MU EDCA parameter set from a trigger frame and applying the information to the MU EDCA parameter set is shown.

[0116] The wireless communication terminal may apply the MU EDCA parameter set based on whether the trigger information received by the wireless communication terminal triggers the multi-user uplink transmission of the wireless communication terminal. Specifically, the wireless communication terminal may apply the MU EDCA parameter set based on whether the user information field of the trigger frame received by the wireless communication terminal indicates the wireless communication terminal. In a specific embodiment, the wireless communication terminal may apply the MU EDCA parameter set when receiving the trigger frame. In this embodiment, in order for the wireless communication terminal to apply the MU EDCA parameters, the basic wireless communication terminal does not send any additional information. However, the basic wireless communication terminal attempts to access the channel for sending the trigger frame, and the wireless communication terminal scheduled for UL MU transmission at this time may also use the existing EDCA parameter set to attempt channel access.

[0117] Therefore, using the trigger information, the basic wireless communication terminal can send information about the wireless communication terminal triggered after the trigger information is sent. Specifically, using the user information field of the trigger frame, the basic wireless communication terminal can send information about the wireless communication terminal triggered after the trigger frame is sent. In a specific embodiment, when the field indicating the resource unit (RU) allocation information included in the user information field indicates a predetermined value, the user information field may indicate that the wireless communication terminal indicated by the corresponding user information field will be triggered after the trigger frame is sent. At this time, when the RU allocation information indicated by the user information field is a predetermined value, the wireless communication terminal can apply the MUEDCA parameter set indicated by the corresponding user information field. In another specific embodiment, if the value of the field indicating the RU allocation information included in the user information field is a predetermined value, the field indicating the RU allocation information may indicate the AC to which the MU EDCA parameter set is applied.

[0118] In these embodiments, the wireless communication terminal indicated by the user information field may ignore the remaining fields except the field indicating the RU allocation information and the field indicating the wireless communication terminal indicated by the user information field in the user information field. In addition, the size of the user information field indicating information about the wireless communication terminal to be triggered after the transmission trigger frame may be smaller than the size of the ordinary user information field. Specifically, the basic wireless communication terminal may send the user information field while omitting the field indicating the RU allocation information of the user information field and at least one of the fields other than the field indicating the wireless communication terminal indicated by the user information field. The user information field indicating information about the wireless communication terminal to be triggered after the transmission trigger frame may indicate information about multiple wireless communication terminals to be triggered after the transmission trigger frame. At this time, the user information field may include a group AID. In another specific embodiment, the user information field may include a broadcast AID.

[0119] exist Fig.12 In the embodiment of (a), the basic wireless communication terminal sends a trigger frame to the wireless communication terminal. The wireless communication terminal indicated by the trigger frame applies the MU EDCA parameter set. At this time, the trigger frame may include information about the wireless communication terminal to be triggered after sending the trigger frame, as described above. Specifically, the format of the trigger frame may be similar to Fig.12 Same as shown in (b).

[0120] The basic wireless communication terminal sends a target wake-up time (TWT) element to signal the wireless communication terminal at the time when the wireless communication terminal should wake up. Specifically, the basic wireless communication terminal can use a beacon frame to send the TWT element. When the basic wireless communication terminal attempts channel access to send a trigger frame in the service period indicated by the TWT element, the wireless communication terminal triggered by the trigger frame can attempt channel access for uplink transmission. In this case, the channel access attempt of the wireless communication terminal can reduce the chance of successful channel access of the basic wireless communication terminal. Therefore, the wireless communication terminal can apply the MU EDCA parameter set based on the TWT element. Reference will be made to Fig.13 Describe this in more detail.

[0121] Fig.13 An operation of a wireless communication terminal according to another embodiment of the present invention obtaining information on a MU EDCA parameter set from a target wake-up time element and applying the information on the MU EDCA parameter set is shown.

[0122] The wireless communication terminal can apply the MU EDCA parameter set based on the TWT element. Specifically, the wireless communication terminal can apply the MU EDCA parameter set based on the service period indicated by the TWT element. At this time, the service period represents the period in which the wireless communication terminal previously agreed to exchange frames with the basic wireless communication terminal. In a specific embodiment, the wireless communication terminal can apply the MU EDCA parameter set from the time before the predetermined time from the start time point of the service period indicated by the TWT element. At this time, the predetermined time can be signaled by the basic wireless communication terminal. Specifically, the predetermined time can be signaled by the basic wireless communication terminal through the elements of the beacon frame. For example, the predetermined time can be signaled by the basic wireless communication terminal through the MU EDCA parameter set element. Specifically, the predetermined time can be signaled by the basic wireless communication terminal through the elements of the beacon frame.

[0123] In addition, the wireless communication terminal may terminate the MU EDCA parameter set application based on the service period indicated by the TWT element. Specifically, when a predetermined time has passed since the service period indicated by the TWT element, the wireless communication terminal may be allowed to terminate the MU EDCA parameter set application. In a specific embodiment, the wireless communication terminal may terminate the MU EDCA parameter set application based on the start time point of the service period indicated by the TWT element. For example, when a predetermined time has passed since the start time point of the service period indicated by the TWT element, the wireless communication terminal may be allowed to terminate the MU EDCA parameter set application. In another specific embodiment, the communication terminal may terminate the MU EDCA parameter set application based on the end time point of the service period indicated by the TWT element. For example, the wireless communication terminal may terminate the MU EDCA parameter set application at the end time point of the service period indicated by the TWT element.

[0124] exist Fig.13 In an embodiment, the basic wireless communication terminal signals a service period for TWT operation by sending a beacon frame including a TWT element. The wireless communication terminal receiving the beacon frame determines the start time point and the end time point of the MU EDCA parameter set based on the TWT element. Specifically, the wireless communication terminal receiving the beacon frame determines the MU EDCA parameter set application start time point based on the start time point of the service period indicated by the TWT element. In addition, the wireless communication terminal receiving the beacon frame determines the MU EDCA parameter set application end time point based on the start time point of the service period indicated by the TWT element. In another specific embodiment, the wireless communication terminal receiving the beacon frame determines the MU EDCA parameter set application end time point based on the end time point of the service period indicated by the TWT element.

[0125] The MU EDCA parameter is a channel access condition that is more unfavorable than a typical EDCA parameter set. Therefore, the wireless communication terminal needs to terminate the application of the MU EDCA parameter set. When the MU EDCA parameter application is terminated, the wireless communication terminal switches the MU EDCA parameter set to a normal EDCA parameter set. Figure 14 to Figure 15 Describe this.

[0126] Fig.14 The operation of the wireless communication terminal terminating the application of MU EDCA parameters according to the embodiment of the present invention is shown.

[0127] If the MU EDCA parameter setting application condition is not met until a specific time has passed since the timer was set, the wireless communication terminal may set the MU EDCA timer to terminate the MU EDCA parameter set application. Specifically, the wireless communication terminal may set the MU EDCA timer when trigger information is received. At this time, when the MU EDCA parameter setting application condition is not met within a period of time after the MU EDCA timer is set, the wireless communication terminal may be allowed to terminate the MU EDCA parameter set application. Specifically, if the ULMU transmission of the wireless communication terminal is not scheduled within a certain period of time from when the MU EDCA timer is not set, the wireless communication terminal may be allowed to terminate the MU EDCA parameter set application.

[0128] In another embodiment, the wireless communication terminal may set the MU EDCA timer when receiving a response to the transmission of a triggered physical layer protocol data unit (PPDU) of the wireless communication terminal. Specifically, when the wireless communication terminal receives a response to the triggered PPDU transmission, the wireless communication terminal may set the MU EDCA timer. This is because if the triggered PPDU transmission of the wireless communication terminal fails, the basic wireless communication terminal may try to trigger the information transmission again. In this embodiment, the wireless communication terminal may be prepared for the case where a response to the triggered PPDU transmission is not received. Specifically, when the wireless communication terminal does not receive a response to the triggered PPDU transmission from the time when the triggered PPDU is sent until a time point after a predetermined time, the wireless communication terminal may set the MU EDCA parameter set timer. At this time, the predetermined time may be aSIFSTime)+aRxPHYStartDelay+(2x aSlotTime).

[0129] exist Fig.14In the embodiment of (a), the wireless communication terminal receives a trigger frame TF from the basic wireless communication terminal. The wireless communication terminal sends a trigger-based PPDU including the MPDU corresponding to TID1 and TID3 to the basic wireless communication terminal. The wireless communication terminal receives an M-BA frame from the basic wireless communication terminal, the M-BA frame indicating an ACK for the MPDU included in the trigger-based PPDU. In this operation, the wireless communication terminal may set MU EDCA timer option 1 when receiving the trigger frame TF, as described above. In addition, the wireless communication terminal may set MU EDCA timer option 2 when receiving the M-BA frame, as described above.

[0130] In addition, when the wireless communication terminal reports to the infrastructure wireless communication terminal a BSR that the buffer for one or more ACs is empty, the wireless communication terminal receives an ACK for data transmission of the corresponding AC and terminates the MU EDCA parameter set application. Fig.14 In the embodiment of (b), the wireless communication terminal reports to the basic wireless communication terminal that the buffer for TID1 is empty while sending the triggered PPDU. Therefore, when the wireless communication terminal receives the M-BA frame for the last transmission of the MPDU corresponding to TID1, the wireless communication terminal converts the MU EDCA parameter set to the ordinary EDCA parameter set Legacy. In another embodiment, the wireless communication terminal sets a first MU EDCA timer according to the reception of trigger information, and sets the MU EDCA timer according to the reception of a response to the triggered PPDU transmission. At this time, the period of the second timer may be shorter than the period of the first MU timer. Specifically, the wireless communication terminal may set the first MU EDCA timer when the trigger information is received, and set the MU EDCA timer when the response to the triggered PPDU transmission is received. Fig.14 In the embodiment of (c), when the wireless communication terminal receives the trigger frame TF, it sets the first MU EDCA timer option 1. In addition, when receiving the M-BA frame, the wireless communication terminal sets the second MU EDCA timer option 2, which expires earlier than the expiration time set by the first MU EDCA timer option.

[0131] In addition, the wireless communication terminal may set the MU EDCA timer according to the MU EDCA parameter application condition. Fig.15 Describe this in detail.

[0132] Fig.15 An operation of a wireless communication terminal terminating the application of MU EDCA parameters according to another embodiment of the present invention is shown.

[0133] When the wireless communication terminal applies MU EDCA parameters, the wireless communication terminal may set a MU EDCA timer. Specifically, when the wireless communication terminal sends a BSR to the basic wireless communication terminal, the wireless communication terminal may apply the MU EDCA parameter set and set the MU EDCA timer. At this time, when the trigger frame received by the wireless communication terminal triggers the data transmission of the AC that sends the BSR, the wireless communication terminal may update the existing MU EDCA timer to a MU EDCA timer that expires later than the existing MU EDCA timer expiration time. Fig.15 In the embodiment of (a), the first station STA1 sends a BSR to the access point AP. At this time, the first station STA1 applies the MU EDCA parameter set and sets the MU EDCA timer. The first station STA1 receives a trigger frame that triggers the service transmission of the AC that sends the BSR from the access point AP. Therefore, the first station STA1 updates the previously set MU EDCA timer to a MU EDCA timer that expires later than the expiration time of the previously set MU EDCA timer.

[0134] In addition, when the wireless communication terminal applies the MU EDCA parameter set based on the UL MU transmission scheduling information included in the beacon frame, the wireless communication terminal may terminate the MU EDCA parameter set application based on the UL MU transmission scheduling information. Specifically, when the beacon frame does not include information about the UL MU transmission scheduling, the wireless communication terminal may be allowed to terminate the MU EDCA parameter set application based on the beacon frame. In addition, if the information about the UL MU transmission scheduling included in the beacon frame indicates that the wireless communication terminal is not scheduled for UL MU transmission, the wireless communication terminal may be allowed to terminate the MU EDCA parameter set application based on the UL MU transmission scheduling information. Fig.15 In the embodiment of (b), the first station STA1 receives a beacon frame from the access point AP. The first station STA1 obtains information about UL MU transmission scheduling from the beacon frame. When the information about UL MU transmission scheduling obtained by the first station STA1 indicates that UL MU transmission of the wireless communication terminal is scheduled, the first station STA1 applies the MU EDCA parameter set. Thereafter, the first station STA1 receives a beacon frame from the access point AP again. The first station STA1 obtains information about UL MU transmission scheduling from the beacon frame. When the information about UL MU transmission scheduling obtained by the first station STA1 indicates that UL MU transmission of the wireless communication terminal is not scheduled, the first station STA1 switches from the MU EDCA parameter set to the normal EDCA parameter set.

[0135] Fig.16 An operation in which a wireless communication terminal according to another embodiment of the present invention applies MU EDCA parameters is shown.

[0136] As described above, when the wireless communication terminal applies the MU EDCA parameters, the wireless communication terminal may set the MU EDCA timer. Fig.14 As in the embodiment described in the foregoing, the wireless communication terminal may set the MU EDCA timer when receiving a response to a triggered PPDU transmission. Therefore, the wireless communication terminal may apply the MU EDCA parameter set when receiving a response to a triggered PPDU transmission. Specifically, when the wireless communication terminal receives a response to a triggered PPDU transmission, the wireless communication terminal may apply the MU EDCA parameter set. In a specific embodiment, the wireless communication terminal may apply the MU EDCA parameter set when the following three conditions are met. The first condition is that the wireless communication terminal receives a trigger frame that triggers the wireless communication terminal to be sent from the basic wireless communication terminal. Specifically, the wireless communication terminal receives a trigger frame indicating the AID of the wireless communication terminal. At this time, the trigger frame may be a basic trigger frame. In a specific embodiment, the first condition may include the following situation, the user information field of the trigger frame indicates random access and the wireless communication terminal sends a triggered PPDU through random access. The second condition is to send a triggered PPDU including a QoS data frame to the basic wireless communication terminal according to the reception of the trigger frame. The third condition is that the wireless communication terminal receives an immediate response to the triggered PPDU from the basic wireless communication terminal. At this time, the immediate response may indicate that the recipient sends a response to the initiator within a predetermined time period during the same transmit opportunity (TXOP). When these three conditions are met, the wireless communication terminal may apply the MU EDCA parameter set to the AC of the QoS data frame included in the triggered PPDU sent by the wireless communication terminal. In addition, at the time point when the immediate response reception to the triggered PPDU from the basic wireless communication terminal is completed, the wireless communication terminal may apply the MU EDCA parameter set. For example, at the time point when the M-BA frame reception of the triggered PPDU from the basic wireless communication terminal is completed, the wireless communication terminal may apply the MU EDCA parameter set. In addition, when the above conditions are met before the MU EDCA timer expires, the wireless communication terminal may update the MU EDCA timer with a time period corresponding to the MU EDCA parameter set. When the MU EDCA timer expires, the wireless communication terminal terminates the application of the MU EDCA parameter set.

[0137] exist Fig.16In the embodiment of (a), the first station STA1 receives a trigger frame TF from the basic wireless communication terminal. At this time, the trigger frame TF indicates the AID of the first station STA1. The first station STA1 sends a trigger-based PPDU HE TRIG PPDU including an MPDU corresponding to TID1 and TID3 to the basic wireless communication terminal. The first station STA1 receives an M-BA frame in response to the trigger-based PPDU HE TRIG PPDU from the basic wireless communication terminal. When the first station STA1 completes the reception of the M-BA frame, with respect to the first station STA1, the basic wireless communication terminal applies the MU EDCA parameters to the AC indicated by the M-BA frame as ACK. At this time, the first station STA1 sets the MU EDCA timer for the AC indicated by the M-BA frame as ACK.

[0138] Even if the PPDU including the immediate response to the triggered PPDU also includes another frame, the wireless communication terminal can apply the MU EDCA parameter set at the time point when the reception of the immediate response to the triggered PPDU from the infrastructure wireless communication terminal is completed. Fig.16 In the embodiment of (b), while sending the M-BA frame for the triggered PPDU HE TRIG PPDU to the first station STA1, the basic wireless communication terminal sends another frame DL together. When the first station STA1 completes the reception of the PPDU including the M-BA frame and the other frame DL, the first station STA1 applies the MU EDCA parameters to the AC indicated by the M-BA frame as ACK. At this time, the first station STA1 sets the MU EDCA timer for the AC indicated by the M-BA frame as ACK.

[0139] In addition, when downlink transmission and uplink transmission are continuously performed in the same TXOP, the wireless communication terminal may apply the MU EDCA parameter set to the end time point of the corresponding TXOP. Fig.16 In the embodiment of (c), the basic wireless communication terminal sends an M-BA frame for the triggered PPDU HE TRIG PPDU sent by the first station STA1 together with another frame DL, such as Fig.16 (b) is the same as in the embodiment. At this time, the first station STA1 performs uplink transmission to the basic wireless communication terminal again. When the first station STA1 receives the response to the uplink transmission, the basic wireless communication terminal applies the MU EDCA parameters to the AC in which the M-BA frame indicates ACK with respect to the first station STA1. At this time, the first station STA1 sets the MU EDCA timer for the AC in which the M-BA frame indicates ACK.

[0140] In another specific embodiment, under the condition that the wireless communication terminal applies the MU EDCA parameter set, the trigger frame received by the wireless communication terminal may include a trigger frame variant, such as a BSR polling frame. In addition, the wireless communication terminal may receive a UL MU response schedule instead of a trigger frame. Specifically, when the wireless communication terminal sends QoS data based on a trigger frame variant or a UL MU response schedule, the wireless communication terminal may apply the MU EDCA parameter set.

[0141] In the above embodiment, the wireless communication terminal may determine the MU EDCA parameter set application time and the MU EDCA timer setting time based on the type of response requested by the MPDU included in the triggered PPDU. Figure 17 to Figure 18 Describe this.

[0142] Fig.17 An A-MPDU generated by a wireless communication terminal according to an embodiment of the present invention and a corresponding response type of the A-MPDU are shown.

[0143] The wireless communication terminal can aggregate one or more MPDUs of QoS data frames, action frames, and control frames into one PSDU and send it to the A-MPDU. Depending on whether the QoS data requests Ack, the A-MPDU including the QoS data frame can be classified as a context of data enable immediate response (DEIR) or data enable no immediate response (DENIR). The wireless communication terminal receiving the A-MPDU can determine whether the QoS data requests Ack based on the value of the ACK policy subfield of the QoS control field of the MAC header. At this time, the value of the ACK policy subfield is indicated for each TID. In addition, the wireless communication terminal can divide the service category of the TID into QoSACK and QoSNoACK. The wireless communication terminal sending the A-MPDU does not provide the BA protocol for the TID corresponding to the QoSNoACK service class. In addition, the wireless communication terminal sending the A-MPDU sets the value of the ACK policy subfield of the TID corresponding to the QoSNoACK service class to no ACK.

[0144] When the wireless communication terminal aggregates multiple MPDUs corresponding to one TID and sends an A-MPDU, the immediate response context of the corresponding A-MPDU is determined according to whether the A-MPDU includes an MPDU for which the TID requests ACK. Specifically, when the A-MPDU including only multiple MPDUs corresponding to one TID includes an MPDU for which the TID requests ACK, the immediate response context of the corresponding A-MPDU is DEIR. In addition, when the A-MPDU including only multiple MPDUs corresponding to one TID includes an MPDU for which the TID does not request ACK, the immediate response context of the corresponding A-MPDU is DENIR.

[0145] As described above, the wireless communication terminal may aggregate multiple MPDUs corresponding to multiple TIDs to generate a multi-TID A-MPDU. The immediate response context of the multi-TID A-MPDU may be classified as follows. If the multi-TID A-MPDU includes one or more TIDs requesting ACK, the immediate response context of the corresponding multi-TID A-MPDU is DEIR. In addition, if the multi-TID A-MPDU includes only TIDs not requesting ACK or frames without TIDs, the immediate response context of the corresponding multi-TID A-MPDU is DENIR. Fig.17 In the embodiment of (a), the A-MPDU includes an MPDU with a TID of 1, an MPDU with a TID of 2, an MPDU with a TID of 3, and an action frame. The MPDU with a TID of 3 does not request an Ack, but each of the MPDU with a TID of 1, the MPDU with a TID of 2, and the action frame requests an immediate response. Therefore, the immediate response context of the A-MPDU is DEIR. Fig.17 In the embodiment of (b), the A-MPDU includes an MPDU with a TID of 1, an MPDU with a TID of 2, an MPDU with a TID of 3, and a No ACK action frame. Each of the MPDU with a TID of 1, the MPDU with a TID of 2, and the action frame requests an immediate response. The MPDU with a TID of 1, the MPDU with a TID of 2, the MPDU with a TID of 3, and the No ACK action frame do not request an immediate response. Therefore, the immediate response context of the A-MPDU is DENIR.

[0146] In reference Fig.16 In the described embodiment, the wireless communication terminal applies MU EDCA parameters and sets the MU EDCA timer based on an immediate response to the MPDU included in the trigger-based PPDU. Fig.17 As described above, the QoS data frame included in the triggered PPDU may not request Ack. When the QoS data frame included in the triggered PPDU does not request Ack, reference Fig.18 The MU EDCA parameter set application operation and MU EDCA timer setting operation of a wireless communication terminal are described.

[0147] Fig.18 The operation of a wireless communication terminal applying MU EDCA parameters according to another embodiment of the present invention is shown.

[0148] When the QoS data frame included in the triggered PPDU sent by the wireless communication terminal does not request ACK, the wireless communication terminal can apply the MU EDCA parameter set at the time point when the transmission of the triggered PPDU ends. In addition, if the QoS data frame included in the triggered PPDU sent by the wireless communication terminal does not request ACK, the wireless communication terminal can set the MU EDCA timer at the time point when the transmission of the triggered PPDU ends. Fig.16 As in the described embodiment, even if the wireless communication terminal receives a triggered frame variant or sends a triggered PPDU based on UL MU response scheduling, the wireless communication terminal can apply the MU EDCA parameter set at the time point when the transmission of the triggered PPDU ends. At this time, the wireless communication terminal can set the MU EDCA timer at the time point when the transmission of the triggered PPDU ends. In another specific embodiment, when the immediate response context of the A-MPDU included in the triggered PPDU sent by the wireless communication terminal is DENIR, the wireless communication terminal can apply the MU EDCA parameter set at the time point when the transmission of the triggered PPDU ends. In addition, when the immediate response context of the A-MPDU included in the triggered PPDU sent by the wireless communication terminal is DENIR, the wireless communication terminal can set the MU EDCA timer at the time point when the transmission of the triggered PPDU ends. Fig.18 In the embodiment of (a), the wireless communication terminal receives a trigger frame TF from the basic wireless communication terminal. Upon receiving the trigger frame, the wireless communication terminal sends a triggered PPDU HE TRIG PPDU including an A-MPDU whose immediate response context is DENIR to the basic wireless communication terminal. The wireless communication terminal applies the MU EDCA parameter set and starts the MU EDCA timer at the time when the transmission of the triggered PPDU HE TRIG PPDU ends.

[0149] In another specific embodiment, when the QoS data frame included in the triggered PPDU sent by the wireless communication terminal does not request ACK, the wireless communication terminal can apply the MU EDCA parameter set when a predetermined time has passed after the time point at which the transmission of the triggered PPDU ends. In addition, when the QoS data frame included in the triggered PPDU sent by the wireless communication terminal does not request ACK, the wireless communication terminal can set the MU EDCA timer when a predetermined time has passed after the time point at which the transmission of the triggered PPDU ends. In another specific embodiment, when the immediate response context of the A-MPDU included in the triggered PPDU sent by the wireless communication terminal is DENIR, the wireless communication terminal can apply the MU EDCA parameter set when a predetermined time has passed after the time point at which the transmission of the triggered PPDU ends. In addition, if the immediate response context of the A-MPDU included in the triggered PPDU sent by the wireless communication terminal is DENIR, the wireless communication terminal can set the MU EDCA timer when a predetermined time has passed after the time point at which the transmission of the triggered PPDU ends. At this time, the predetermined time may be a short interframe space (SIFS). In another specific embodiment, the predetermined time may be the sum of the predetermined representative ACK transmission time and SIFS. Fig.18 In the embodiment of (b), the wireless communication terminal receives a trigger frame TF from the basic wireless communication terminal. Upon receiving the trigger frame, the wireless communication terminal sends a triggered PPDU HE TRIG PPDU including an A-MPDU whose immediate response context is DENIR to the basic wireless communication terminal. When a predetermined time has passed after the transmission of the triggered PPDU HE TRIG PPDU ends and the MU EDCA timer is started, the wireless communication terminal applies the MU EDCA parameter set. At this time, the predetermined time may be SIFS. In another specific embodiment, the predetermined time may be the sum of SIFS and a predetermined representative ACK transmission time Ack time.

[0150] In another specific embodiment, if the QoS data frame included in the triggered PPDU transmitted by the wireless communication terminal does not request ACK, the wireless communication terminal may apply the MU EDCA parameter set based on an immediate response to the triggered PPDU transmission of another wireless communication terminal, which transmits the triggered PPDU simultaneously with the wireless communication terminal. In another specific embodiment, when the immediate response context of the A-MPDU included in the triggered PPDU transmitted by the wireless communication terminal is DENIR, the wireless communication terminal may apply the MU EDCA parameter set based on an immediate response to the triggered PPDU transmission of another wireless communication terminal, which transmits the triggered PPDU simultaneously with the wireless communication terminal. In these embodiments, when the wireless communication terminal receives an immediate response to the triggered PPDU transmission of another wireless communication terminal that transmits the triggered PPDU simultaneously with the wireless communication terminal, the wireless communication terminal may apply the MU EDCA parameter set. When the wireless communication terminal does not receive an immediate response to the transmission of a triggered PPDU by another wireless communication terminal that simultaneously transmits a triggered PPDU with the wireless communication terminal, the wireless communication terminal may apply the MU EDCA parameter set when a predetermined period of time has passed since the trigger-based PPDU transmitted by the wireless communication terminal was transmitted. The time when a predetermined period of time has passed after the trigger-based PPDU transmitted by the wireless communication terminal is transmitted may be when SIFSTime+aSlotTime+aRxPHYStart-delay has passed from the time point after the PHY-TXEND.confirm primitive.

[0151] In addition, if the QoS data frame included in the triggered PPDU transmitted by the wireless communication terminal does not request ACK, the wireless communication terminal may set the MU EDCA timer based on an immediate response to the triggered PPDU transmission of another wireless communication terminal, which transmits the triggered PPDU simultaneously with the wireless communication terminal. In another specific embodiment, when the immediate response context of the A-MPDU included in the triggered PPDU transmitted by the wireless communication terminal is DENIR, the wireless communication terminal may set the MU EDCA timer based on an immediate response to the triggered PPDU transmission of another wireless communication terminal, which transmits the triggered PPDU simultaneously with the wireless communication terminal. In these embodiments, when the wireless communication terminal receives an immediate response to the triggered PPDU transmission of another wireless communication terminal that transmits the triggered PPDU simultaneously with the wireless communication terminal, the wireless communication terminal may set the MU EDCA timer. When the wireless communication terminal does not receive an immediate response to the triggered PPDU transmission of another wireless communication terminal that transmits the triggered PPDU simultaneously with the wireless communication terminal, the wireless communication terminal may set the MU EDCA timer when a predetermined period of time has passed since the trigger-based PPDU transmitted by the wireless communication terminal has been transmitted. The time when the predetermined period elapses after the trigger-based PPDU transmitted by the wireless communication terminal is transmitted may be the time when SIFSTime+aSlotTime+aRxPHYStart-delay elapses from a time point after the PHY-TXEND.confirm primitive.

[0152] exist Fig.18 In the embodiment of (c), the wireless communication terminal receives a trigger frame TF and sends a triggered PPDU HE TRIG PPDU including an A-MPDU whose immediate response context is DENIR to the basic wireless communication terminal. When the wireless communication terminal sends the triggered PPDU HE TRIG PPDU, the wireless communication terminal simultaneously detects the transmission of an M-BA frame based on the triggered PPDU of another wireless communication terminal that sends the triggered PPDU. The wireless communication terminal applies the MU EDCA parameter set at the time point when the reception of the M-BA frame based on the triggered PPDU for the other wireless communication terminal ends, and starts the MU EDCA timer. When the wireless communication terminal does not receive the triggered PPDU HE TRIG PPDU, the wireless communication terminal detects the transmission of an M-BA frame based on the triggered PPDU of another wireless communication terminal that sends the triggered PPDU. Fig.18In the embodiment of (d), when the M-BA frame of the triggered PPDU is used for another wireless communication terminal, the wireless communication terminal applies the MU EDCA parameter set at a time point after SIFSTime+aSlotTime+aRxPHYStart-delay when sending the triggered PPDU HE TRIG PPDU, and starts the MU EDCA timer.

[0153] In these embodiments, the wireless communication terminal may apply the MU EDCA parameter set to the AC corresponding to the QoS data frame transmitted through the trigger-based PPDU, as described in reference Fig.16 As in the described embodiments.

[0154] In another specific embodiment, when the wireless communication terminal sends a triggered PPDU, the wireless communication terminal may be restricted from sending a QoS data frame that does not request an ACK. Specifically, when the wireless communication terminal sends a triggered PPDU, the wireless communication terminal may be restricted from sending a QoS data frame having an Ack policy subfield set to No Ack.

[0155] Will refer to Figures 19 to 21 The operation of a wireless communication terminal applying a separate MU EDCA parameter set is described.

[0156] Fig.19 The operation of a wireless communication terminal applying a MU EDCA parameter set according to an embodiment of the present invention is shown.

[0157] As described above, the EDCA parameter set may include a backoff timer and CW-related parameters. When the wireless communication terminal switches the first EDCA parameter set currently in use to the second EDCA parameter set, the wireless communication terminal may change the value of the backoff timer currently used in the backoff process based on the second EDCA parameter set. At this time, the first EDCA parameter set may be a normal EDCA parameter set, and the second EDCA parameter set may be a MU EDCA parameter set. Moreover, the first EDCA parameter set may be a MUEDCA parameter set, and the second EDCA parameter set may be a normal EDCA parameter set. This is because if the wireless communication terminal does not change the value of the backoff timer when switching the EDCA parameter set, the effect of changing the channel access priority caused by switching the EDCA parameter set may not be immediately applied.

[0158] In a specific embodiment, the wireless communication terminal may multiply the backoff timer currently used in the backoff process by a value determined based on the second EDCA parameter set. At this time, the value determined based on the second EDCA parameter set may be a value determined based on the CW parameter value of the second EDCA parameter set. Specifically, the value determined based on the second parameter set may be a value obtained by dividing the CWmin of the second EDCA parameter set by the CWmin of the first EDCA parameter set. In another specific embodiment, the value determined based on the second EDCA parameter set may be a value obtained by dividing the CWmax of the second EDCA parameter set by the CWmax of the first EDCA parameter set. In another embodiment, when the value of the backoff timer currently used by the wireless communication terminal in the backoff process is less than the CWmin of the second EDCA parameter set, the wireless communication terminal may set the value of the backoff timer to the CWmin of the second EDCA parameter set. In addition, when the value of the backoff timer currently used by the wireless communication terminal in the backoff process is greater than the CWmax of the second EDCA parameter set, the wireless communication terminal may set the value of the backoff timer to the CWmax of the CWmax of the second EDCA parameter set.

[0159] When the wireless communication terminal switches the currently used first EDCA parameter set to the second EDCA parameter set, the wireless communication terminal may change the parameter value of the CW currently used in the backoff process based on the second EDCA parameter set. At this time, the parameters of CW may include CWmin and CWmax. In addition, the EDCA parameter set may include a short retry limit and a long retry limit, which are parameters for adjusting the CW value according to the number of channel retransmission attempts. Moreover, the first EDCA parameter set may be a normal EDCA parameter set, and the second EDCA parameter set may be a MU EDCA parameter set. Moreover, the first EDCA parameter set may be a MU EDCA parameter set, and the second EDCA parameter set may be a normal EDCA parameter set. The wireless communication terminal may increase the value of CW during the backoff process. At this time, the value of CW is limited to the value of CWmax, and the wireless communication terminal may reset the value of CW to CWmin according to the retry limit value. This is because the restriction may not be applied when the wireless communication terminal switches the EDCA parameter set.

[0160] Specifically, when the CW value currently used by the wireless communication terminal in the backoff process is less than the CWmin of the second EDCA parameter set, the wireless communication terminal may set the CW value to the CWmin of the second EDCA parameter set. In addition, when the CW value currently used by the wireless communication terminal in the backoff process is greater than the CWmax of the second EDCA parameter set, the wireless communication terminal may set the CW value to the CWmax of the second EDCA parameter set. In addition, if the QoS short retry counter (QSRC) is greater than the short retry limit or the QoS long retry counter (QLRC) is greater than the short retry limit, the wireless communication terminal may set the CW value to the CWmin of the second EDCA parameter set.

[0161] exist Fig.19 In the embodiment of the present invention, the wireless communication terminal switches the traditional EDCA parameter set for AC BE to the MU EDCA parameter set. At this time, the wireless communication terminal sets the backoff timer value BO MU [BE] is set to the product of the value a[AC] obtained based on the MU EDCA parameter set and the value of the backoff timer BO[BE] in the current backoff process. In addition, the wireless communication terminal sets the CW value CWmu[BE] to the larger value of the CW value CW[BE] in the current backoff process and the CWmin CWmin[BE] in the MU EDCA parameter set. When the wireless communication terminal converts the MU EDCA parameter set to the normal EDCA parameter set, the wireless communication terminal sets the CW value CW[BE] to the smaller value of the CW CWmu[BE] value in the current backoff process and the CWmax CWmax[BE] of the conventional EDCA parameter set.

[0162] Will refer to Fig. 20 The following figures further describe the specific operation of the wireless communication terminal to set the CW.

[0163] Fig. 20 An operation of changing a CW value while changing an EDCA parameter set at a wireless communication terminal according to an embodiment of the present invention is shown.

[0164] The wireless communication terminal changes the CW value in the following three cases during the backoff process.

[0165] 1) When the transmission of the initial PPDU of a TXOP fails and the AC of the MPDU is the primary AC

[0166] 2) When two or more EDCAFs compete in the same wireless communication terminal and a transmission attempt of the wireless communication terminal collides with another EDCAF with a higher priority in the wireless communication terminal

[0167] 3) A PHY-TXBUSY.indication(BUSY) primitive is sent in response to a PHYTXSTART.request primitive, and when a transmission attempt of a wireless communication terminal coordinated by a multiple MAC station management entity (MM-SME) conflicts with a transmission attempt of another wireless communication terminal coordinated by the same MM-SME

[0168] At this time, the wireless communication terminal changes the CW value according to the following rule.

[0169] a) When the QSRC QSRC[AC] corresponding to AC reaches the short retry limit dot11ShortRetryLimit) or the QLRC QLRC[AC] corresponding to AC reaches the long retry limit dot11LongRetryLimit, the wireless communication terminal resets the CW value CW[AC] corresponding to AC to the CWmin value CWmin[AC].

[0170] b) When the value of dot11RobustAVStreamingImplemented is true, and the QoS short discard retry count QSDRC[AC] corresponding to AC reaches dot11ShortDEIRetryLimit, or the QoS long discard retry count QLDRC[AC] of AC reaches dot11LongDEIRetryLimit, the wireless communication terminal resets the CW value CW[AC] corresponding to AC to the CWmin value CWmin[AC].

[0171] c) Otherwise

[0172] c-1) When the CW value CW[AC] corresponding to AC is less than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to (CW)[AC]+1)x2-1.

[0173] c-2) When the CW value CW[AC] corresponding to AC is equal to the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal does not change the CW value CW[AC] corresponding to AC.

[0174] The cases of 1), 2) and 3) are all cases where the wireless communication terminal retries transmission due to transmission failure, internal contention failure, etc. In addition, in a) and b), the wireless communication terminal resets the CW value due to exceeding the number of retries. In c), the wireless communication terminal changes the CW value to retry transmission. In a), b) and c), the wireless communication terminal operates without considering changing the EDCA parameter set. For example, the CW value corresponding to AC is equal to CWmin, and the wireless communication terminal can apply an EDCA parameter set with a CWmin greater than the previous EDCA parameter set. At this time, the wireless communication terminal uses a CW value less than CWmin of the new EDCA parameter set. In addition, the CW value corresponding to AC is equal to CWmax, and the wireless communication terminal can apply an EDCA parameter set with a CWmax less than the previous EDCA parameter set. At this time, the wireless communication terminal uses a CW value greater than CWmax of the new EDCA parameter set. At this time, because this does not correspond to the above conditions c-1) and c-2), the wireless communication terminal may not change the CW value within the range of CWmin and CWmax. Therefore, the operation of the wireless communication terminal in c) may be changed as follows.

[0175] c-1) In the case of a conventional wireless communication terminal (e.g., non-HE STA)

[0176] c-1-1) When the CW value CW[AC] corresponding to AC is less than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to (CW[AC]+1)x2-1.

[0177] c-2-2) When the CW value CW[AC] corresponding to AC is equal to the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal does not change the CW value CW[AC] corresponding to AC.

[0178] c-2) In the case of non-legacy wireless communication terminals (e.g., HE STA)

[0179] c-2-1) When the CW value CW[AC] corresponding to AC is less than the CWmin value CWmin[AC], the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the CWmin value CWmin[AC].

[0180] c-2-2) When the CW value CW[AC] corresponding to AC is less than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to (CW[AC]+1)x2-1.

[0181] c-2-3) When the CW value CW[AC] corresponding to AC is equal to the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal does not change the CW value CW[AC] corresponding to AC.

[0182] c-2-4) When the CW value CW[AC] corresponding to AC is greater than the CWmax value CWmax[AC], the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the CWmax value CWmax[AC].

[0183] In another embodiment, the wireless communication terminal may operate as follows in the above c).

[0184] c-1) In the case of a conventional wireless communication terminal (e.g., non-HE STA)

[0185] c-1-1) When the CW value CW[AC] corresponding to AC is less than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to (CW[AC]+1)x2-1.

[0186] c-2-2) When the CW value CW[AC] corresponding to AC is equal to the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal does not change the CW value CW[AC] corresponding to AC.

[0187] c-2) In the case of non-legacy wireless communication terminals (e.g., HE STA)

[0188] c-2-1) When the CW value CW[AC] corresponding to AC is less than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the larger value of (CW[AC]+1)x2-1 and the CWmin value CWmin[AC].

[0189] c-2-2) When the CW value CW[AC] corresponding to AC is equal to or greater than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the CWmax value CWmax[AC].

[0190] In another embodiment, the wireless communication terminal may operate as follows in the above c).

[0191] c-1) In the case of a conventional wireless communication terminal (e.g., non-HE STA)

[0192] c-1-1) When the CW value CW[AC] corresponding to AC is less than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to (CW[AC]+1)x2-1.

[0193] c-2-2) When the CW value CW[AC] corresponding to AC is equal to the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal does not change the CW value CW[AC] corresponding to AC.

[0194] c-2) In the case of non-legacy wireless communication terminals (HE STA)

[0195] c-2-1) When the CW value CW[AC] corresponding to AC is less than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the larger value of CW[AC]+1)x2-1 and the CWmin value CWmin[AC].

[0196] c-2-2) If the CW value CW[AC] corresponding to AC is equal to the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal does not change the CW value CW[AC] corresponding to AC.

[0197] c-2-3) If the CW value CW[AC] corresponding to AC is greater than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the CWmax value CWmax[AC].

[0198] Fig.21 An operation of changing a CW value while changing an EDCA parameter set at a wireless communication terminal according to an embodiment of the present invention is shown.

[0199] In reference Fig. 20 In the described embodiment, only the operation of the non-legacy wireless communication terminal HE STA is considered. However, similar problems may occur in the legacy wireless communication terminal non-HE STA that applies the MU EDCA parameter set. This is because the legacy wireless communication terminal (e.g., non-HE STA) can change some values ​​of the EDCA parameter set. Therefore, the wireless communication terminal can operate as follows in the above c).

[0200] c) Otherwise

[0201] c-1-3) When the CW value CW[AC] corresponding to AC is less than the CWmin value CWmin[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the CWmin value CWmin[AC].

[0202] c-2) When the CW value CW[AC] corresponding to AC is greater than the CWmin value CWmin[AC] corresponding to AC and is equal to or less than the CWmax value CWmax[AC], the wireless communication terminal sets the CW value CW[AC] corresponding to AC to (CW[AC]+1)x2-1.

[0203] c-3) When the CW value CW[AC] corresponding to AC is greater than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the CWmax value CWmax[AC].

[0204] In another embodiment, the wireless communication terminal may operate as follows in the above c).

[0205] c) Otherwise

[0206] c-1-3) When the CW value CW[AC] corresponding to AC is less than the CWmin value CWmin[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the CWmin value CWmin[AC].

[0207] c-2) When the CW value CW[AC] corresponding to AC is greater than the CWmin value CWmin[AC] corresponding to AC and less than the CWmax value CWmax[AC], the wireless communication terminal sets the CW value CW[AC] corresponding to AC to (CW[AC]+1)x2-1.

[0208] c-3) When the CW value CW[AC] corresponding to AC is equal to the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal does not change the CW value CW[AC] corresponding to AC.

[0209] c-4) When the CW value CW[AC] corresponding to AC is greater than the CWmax value CWmax[AC] corresponding to AC, the wireless communication terminal sets the CW value CW[AC] corresponding to AC to the CWmax value CWmax[AC].

[0210] In another embodiment, the wireless communication terminal may operate as follows in the above c).

[0211] c) Otherwise

[0212] c-1) When the CW value (CW[AC]) corresponding to AC is less than the CWmax value (CWmax[AC]), the wireless communication terminal sets the CW value (CW[AC]) corresponding to AC to (CW[AC]+1)x2-1.

[0213] c-2) When the CW value corresponding to AC (CW[AC]) is equal to or greater than the CWmax value (CWmax[AC]) corresponding to AC, the wireless communication terminal sets the CW value corresponding to AC (CW[AC]) to the CWmax value (CWmax[AC]).

[0214] As described above, the infrastructure wireless communication terminal may signal information about the MU EDCA parameter set. Figure 22 to Figure 23 Describes the specific format of information about MU EDCA parameter sets.

[0215] Fig. 22 A specific format of a MU EDCA parameter set element according to an embodiment of the present invention is shown.

[0216] The MU EDCA parameter set element according to an embodiment of the present invention includes an element ID field and an element ID extension field for identifying the MU EDCA parameter set element. In addition, the MU EDCA parameter set element includes a MU EDCA QoS information field. The MU EDCA QoS information field may include a MU EDCA parameter set update count field, whose value changes when the MU EDCA parameter set changes. Specifically, when the basic wireless communication terminal changes the MU EDCA parameter set, the basic wireless communication terminal may increment the value of the MU EDCA parameter set update count field by 1. The wireless communication terminal receiving the MU EDCA parameter set element may determine whether to change the MU EDCA parameter set based on the MU EDCA parameter set update count field value. Other fields in the MU QoS information field except the MU EDCA parameter set update count field may have the same format as the EDCA QoS information field.

[0217] In addition, the MU EDCA parameter set element may include information about the MU EDCA timer. Specifically, the MU EDCA parameter set element may include information indicating the expiration time of the MU EDCA timer.

[0218] In addition, the MU EDCA parameter set element includes a plurality of MU AC parameter record fields indicating information corresponding to each AC. Specifically, the MU EDCA parameter set element includes a MU AC_BE parameter record field, a MU AC_BK parameter record field, a MUAC_VI parameter record field, and a MU AC_VO parameter record field. The MU AC parameter record field may include an ACI / AIFSN field and an ECWmin / ECWmax field. The wireless communication terminal receiving the MU EDCA parameter set element applies the MU EDCA parameter set information corresponding to each AC based on the MU AC parameter record field. Specifically, the wireless communication terminal receiving the MU EDCA parameter set element sets a management information base (MIB) attribute based on the MU AC parameter record field.

[0219] Fig.23 A specific format of a MU EDCA parameter set element according to another embodiment of the present invention is shown.

[0220] Even if the basic wireless communication terminal does not send the MU EDCA parameter set element in the beacon frame, the basic wireless communication terminal may send the MU QoS information field using the beacon frame. Specifically, the basic wireless communication terminal may send the MU QoS information field through an element other than the MU EDCA parameter set element. In a specific embodiment, the basic wireless communication terminal may send the MU QoS information field through a QoS-related element other than the MU EDCA parameter set element.

[0221] In another specific embodiment, the basic wireless communication terminal may send a MU EDCA parameter set element that does not include the MU QoS information field. In this case, the specific format of the MU EDCA parameter set element may be as follows: Fig.23 As shown in . A wireless communication terminal receiving the QoS information field can determine whether the wireless communication terminal can not apply the changed EDCA parameter set based on the EDCA parameter set update count field. When it is determined that the wireless communication terminal does not apply the changed EDCA parameter set and the beacon frame does not include the EDCA parameter set element, the wireless communication terminal can request to send the EDCA parameter set element by sending a probe request frame to the basic wireless communication terminal. When the basic wireless communication terminal is not allowed to send the MU QoS information field together with other elements except the MU EDCA parameter set element, the MU QoS information field may not perform the same role as the above-mentioned QoS information field and also eliminate the need to send the MU QoS information field. Therefore, when it is not allowed to send the MU QoS information field together with other elements except the MU EDCA parameter set element, the basic wireless communication terminal can send the MU EDCA parameter set element that does not include the MU QoS information field.

[0222] The wireless communication terminal performs an internal contention process for data corresponding to each of the multiple ACs using an internal EDCA queue. Specifically, the wireless communication terminal may operate multiple EDCA queues classified according to the access category of the data stored in the queue. In addition, the wireless communication terminal may perform a backoff process for accessing the channel based on a time corresponding to a backoff timer in each of the multiple EDCA queues. At this time, reference is made to Figure 24 to Figure 27 A method for a wireless communication terminal to use an EDCA queue is described in detail.

[0223] Fig.24 An EDCA operation after UL MU transmission of a wireless communication terminal according to an embodiment of the present invention is shown.

[0224] The wireless communication terminal may operate as follows at the boundary of each time slot in the backoff process.

[0225] 1) When the back-off timer is not 0, the wireless communication terminal decrements the value of the back-off timer by 1.

[0226] 2) When data exists in the EDCA queue and the backoff timer is 0, and transmission is not attempted in another EDCA queue with a high user priority (UP), the wireless communication terminal starts a transmission sequence for data of the corresponding EDCA queue.

[0227] 3) When data exists in an EDCA queue and the backoff timer is 0, and transmission is attempted in another EDCA queue with a high user priority (UP), the wireless communication terminal performs an operation according to an internal conflict.

[0228] 4) In other cases, the wireless communication terminal does not perform any operation.

[0229] However, when the backoff timer is 0 and the EDCA queue of the wireless communication terminal is empty, there is a problem because it is not clearly defined what kind of operation the wireless communication terminal should perform. Specifically, in the following case, when the backoff timer is 0, the EDCA queue of the wireless communication terminal may be empty.

[0230] As described above, the basic wireless communication terminal can trigger the uplink transmission of the wireless communication terminal by sending trigger information. At this time, the basic wireless communication terminal can obtain the TXOP for transmitting the trigger information through the backoff process. Therefore, the wireless communication terminal can maintain the backoff timer of the AC of the data sent by UL MU transmission in the state before UL MU transmission. At this time, the wireless communication terminal can attempt to access the channel by resuming the backoff process of the corresponding AC. Before the backoff timer reaches 0, the data may not reach the EDCA queue of the AC.

[0231] In addition, as referenced Figures 19 to 21 As described above, if it is not the case that the wireless communication terminal attempts to transmit and fails, the CW value can be maintained even when the EDCA parameter set is changed. In addition, when the EDCA queue of the corresponding AC is empty and new data arrives at the corresponding EDCA queue, the wireless communication terminal obtains a random integer value within the current CW and sets the backoff timer. Therefore, the wireless communication terminal can use the CW calculated according to the previous EDCA parameter set to obtain a new backoff timer. For example, in Fig.24In an embodiment of the present invention, the wireless communication terminal receives a trigger frame TF from the basic wireless communication terminal. At this time, the wireless communication terminal stops the backoff process for the data in which the AC is VO. The wireless communication terminal maintains a backoff timer of 4 and a CW value of 127. The wireless communication terminal sends a trigger-based PPDU including QoS data TID 1 and TID 3 in which the AC is VO to the basic wireless communication terminal based on the trigger. The wireless communication terminal receives an M-BA frame from the basic wireless communication terminal. The wireless communication terminal receives the M-BA frame and applies the MU EDCA parameter set as described above. Thereafter, the wireless communication terminal restarts the backoff process, in which the value of the backoff timer is 4 and the CW value is 127. The channel accessed by the wireless communication terminal is idle for a time corresponding to the AIFS and a time corresponding to the backoff timer value of 4. Therefore, the backoff timer becomes 0. However, because the wireless communication terminal uses the triggered PPDU to send all data in which the AC is VO, the EDCA queue of the VO is empty. When new data arrives at the EDCA queue for the VO of the wireless communication terminal, the wireless communication terminal obtains a random value 66 within the existing CW value 127 and sets it as the backoff timer value, regardless of the CWmin and Cwmax of the MU EDCA parameter set. In addition, regardless of UL MU transmission, if the EDCA queue is empty and the backoff timer is 0, this may occur in the following case. The wireless communication terminal sends all data of the EDCA queue for the main AC, and additional data may not arrive at the EDCA queue for the main AC until the value of the backoff timer reaches 0. In addition, when the basic wireless communication terminal performs DLMU transmission using MU-MIMO or DL ​​OFDMA, the basic wireless communication terminal can occupy a channel with the main AC and send data corresponding to ACs other than the main AC together with the data corresponding to the main AC. At this time, the backoff timer corresponding to the AC other than the main AC remains unchanged, and the EDCA queue of the corresponding AC can be empty. In addition, if the (A-)MSDU corresponding to any AC among the ACs with the BA protocol is maintained and the lifetime of the corresponding MSDU expires, the wireless communication terminal can discard the corresponding (A-)MSDU. At this time, when the EDCA queue of any AC of the wireless communication terminal is empty, the backoff timer can reach 0. If the EDCA queue is empty and the backoff timer is 0, the reference Figure 25 to Figure 27 The operation of a wireless communication terminal at a time slot boundary is described in detail.

[0232] Fig.25 The operation of the wireless communication terminal when the EDCA queue of the wireless communication terminal according to the embodiment of the present invention is empty and the backoff timer is 0 is shown.

[0233] When the EDCA queue is empty and the backoff timer is 0, the wireless communication terminal may not perform any operation at the time slot boundary. Specifically, the wireless communication terminal may maintain the backoff timer at 0. In addition, the wireless communication terminal may not start the transmission sequence. In a specific embodiment, the wireless communication terminal may maintain all state variables of the EDCA function (EDCAF) without modification. Fig.25 In the embodiment of the present invention, when the EDCA queue of the wireless communication terminal for VO is empty, the backoff timer BO[VO] reaches 0. At this time, the wireless communication terminal does not perform any operation.

[0234] Fig.26 An operation of a wireless communication terminal when an EDCA queue of the wireless communication terminal according to another embodiment of the present invention is empty and the backoff timer is 0 is shown.

[0235] When the EDCA queue is empty and the backoff timer is 0, the wireless communication terminal can resume the backoff process at the time slot boundary. At this time, the wireless communication terminal can maintain the CW value without modification. This is because this is not a situation where the wireless communication terminal cannot transmit, and there is no need to double the CW. Specifically, the wireless communication terminal can maintain all state variables of EDCAF except the backoff timer. In addition, when the EDCA queue is empty and the backoff timer is 0 again, the wireless communication terminal can start the backoff process again. Fig.26 In the embodiment of the present invention, when the EDCA queue of the wireless communication terminal for VO is empty, the back-off timer BO[VO] reaches 0. The wireless communication terminal obtains a random value of 10 in the CW CW[VO] corresponding to VO while maintaining all other EDCAF state variables, and sets the back-off timer BO[VO] with 10.

[0236] Fig. 27 An operation of a wireless communication terminal when an EDCA queue of the wireless communication terminal according to another embodiment of the present invention is empty and the backoff timer is 0 is shown.

[0237] When the EDCA queue is empty and the backoff timer is 0, the wireless communication terminal can initiate EDCAF at the time slot boundary. At this time, the wireless communication terminal can set the CW to CWmin. In addition, the wireless communication terminal can set QSRC and OLRC to initial values. Specifically, the wireless communication terminal can set QSRC and OLRC to 0. The wireless communication terminal initializes EDCAF and then starts the backoff process again. At this time, the wireless communication terminal can maintain the CW value without modification. This is because this is not a situation where the wireless communication terminal cannot send, and there is no need to double the CW.

[0238] In addition, when the EDCA queue is empty and the backoff timer is 0 again, the wireless communication terminal may initiate EDCAF at the time slot boundary again. When the state variable of EDCAF maintains the initial value to prevent meaningless initialization, the wireless communication terminal may not perform initialization.

[0239] Fig.28 The operation of the wireless communication terminal according to the embodiment of the present invention is shown.

[0240] According to an embodiment of the present invention, a wireless communication terminal accesses a channel according to the priority of data to be sent (S2801). Specifically, the wireless communication terminal can access the channel according to the above-mentioned EDCA process. At this time, the wireless communication terminal can be a basic wireless communication terminal. In addition, the wireless communication terminal can be a wireless communication terminal associated with the basic wireless communication terminal.

[0241] The wireless communication terminal that wirelessly communicates with the basic wireless communication terminal may switch the parameter set for channel access from the first parameter set to the second parameter set based on whether UL MU transmission is scheduled. Specifically, the wireless communication terminal may switch the parameter set for channel access from the first parameter set to the second parameter set based on whether the basic wireless communication terminal triggers the UL MU transmission participation of the wireless communication terminal. In addition, the basic wireless communication terminal sends a trigger frame to the wireless communication terminal, and the basic wireless communication terminal may trigger the UL MU transmission participation of the wireless communication terminal. Depending on whether the user information field of the trigger frame includes the AID of the wireless communication terminal, the wireless communication terminal may determine whether the basic wireless communication terminal triggers the UL MU transmission participation of the wireless communication terminal.

[0242] At this time, the parameter set for channel access may be a parameter set for accessing the channel according to the priority of the data. Specifically, the parameter set for channel access may be the above-mentioned EDCA parameter set. Specifically, the EDCA parameter set may include CW parameters. At this time, the CW parameters may include at least one of CWmin and CWmax. In addition, the EDCA parameter set may include a parameter value related to the predetermined time for the wireless communication terminal to wait for the start of the backoff process. At this time, the predetermined time may be the above-mentioned AIFS.

[0243] In addition, the wireless communication terminal may determine whether to switch from the first parameter set to the second parameter set for the data of each access category. In addition, when the wireless communication terminal sends a BSR, the wireless communication terminal may switch from the first parameter set to the second parameter set. In another specific embodiment, when the wireless communication terminal obtains information about UL MU transmission, the wireless communication terminal may switch from the first parameter set to the second parameter set. In another specific embodiment, the wireless communication terminal may send a triggered PPDU to the basic wireless communication terminal according to the trigger of the basic wireless communication terminal. At this time, the wireless communication terminal may switch from the first parameter set to the second parameter set according to an immediate response to the MPDU included in the triggered PPDU. At this time, when the wireless communication terminal receives an immediate response to the MPDU included in the triggered PPDU, the wireless communication terminal may switch from the first parameter set to the second parameter set. The MPDU included in the triggered PPDU may be a QoS data frame.

[0244] When the second parameter set application condition is not met until a certain time has passed since the timer was set, the wireless communication terminal may set a second parameter set timer for terminating the MU EDCA parameter set application. Specifically, based on whether the wireless communication terminal receives an immediate response to the MPDU included in the triggered PPDU, the wireless communication terminal may set the second parameter set timer according to the immediate response reception. When the second parameter set timer expires, the wireless communication terminal may be allowed to terminate the second parameter set application. In addition, when the wireless communication terminal switches from the first parameter set to the second parameter set, the wireless communication terminal may set the second parameter set timer. In addition, the wireless communication terminal may determine when to switch from the first parameter set to the second parameter set according to the type of response requested by the MPDU included in the triggered PPDU. In addition, the wireless communication terminal may determine when to set the second parameter set timer according to the type of response requested by the MPDU included in the triggered PPDU. When the MPDU included in the triggered PPDU sent by the wireless communication terminal does not request ACK, the wireless communication terminal may set the second parameter set timer at the end of the transmission of the triggered PPDU. In addition, the wireless communication terminal may set the second parameter set timer for each access category. Specifically, when the MPDU included in the triggered PPDU does not request ACK, the wireless communication terminal may switch the parameter set from the first parameter set to the second parameter set, and set the second parameter set timer when the transmission of the triggered PPDU ends. As described above, the MPDU included in the triggered PPDU may be a QoS data frame. The specific operation of the wireless communication terminal may be the same as that of the reference Figures 6 to 18 Same as described.

[0245] In addition, when the wireless communication terminal performs the backoff process, the parameters of the parameter set used in the backoff process can be changed. When the CW value is greater than CWmax, the wireless communication terminal can set the CW value to CWmax. In addition, when the CW value is less than CWmin, the wireless communication terminal can set the CW value to CWmin. Specifically, when the wireless communication terminal switches the first parameter set currently in use to the second parameter set, the wireless communication terminal can change the value of the backoff timer currently used in the backoff process based on the second parameter set. In a specific embodiment, the wireless communication terminal may multiply the backoff timer currently used in the backoff process by a value determined based on the second parameter set. When the wireless communication terminal switches the first parameter set currently in use to the second parameter set, the wireless communication terminal can change the parameter value of the CW currently used in the backoff process based on the second parameter set. At this time, the parameters of CW may include CWmin and CWmax. Specifically, the wireless communication terminal can change the backoff timer with the reference value. Figures 19 to 21 The described embodiments operate in the same manner.

[0246] The wireless communication terminal may operate a plurality of queues classified according to the access category of the data stored in the queue. In addition, the wireless communication terminal may perform a backoff process for accessing the channel based on the time corresponding to the backoff timer in each of the plurality of queues. At this time, the queue may represent the above-mentioned EDCA queue. When there is no data stored in the queue and the backoff timer corresponding to the queue is 0, the wireless communication terminal may not perform any operation at the time slot boundary. At this time, the wireless communication terminal may maintain the backoff timer to 0. In another specific embodiment, the wireless communication terminal may resume the backoff process at the time slot boundary. At this time, the wireless communication terminal may maintain the CW value without modification. In another specific embodiment, the wireless communication terminal may initialize the channel access parameter set at the time slot boundary. At this time, the wireless communication terminal may set the CW to CWmin. In addition, the wireless communication terminal may set QSRC and OLRC to initial values. Specifically, the wireless communication terminal may set QSRC and OLRC to 0. Specifically, the wireless communication terminal may use the same backoff process as the reference. Figure 24 to Figure 27 The described embodiments operate in the same manner.

[0247] The wireless communication terminal sends data via the accessed channel (S2803).

[0248] 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.

[0249] 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.

[0250] 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 basic wireless communication terminal, the wireless communication terminal comprising: Transceiver; and a processor for processing a radio signal received by the transceiver or a radio signal sent by the transceiver, Wherein, the processor is configured to: receiving a trigger frame from the infrastructure wireless communication terminal using the transceiver, wherein the trigger frame triggers an orthogonal frequency division multiple access (OFDMA) uplink transmission in which a multi-user uplink transmission of the wireless communication terminal participates and allocates a resource unit to the wireless communication terminal, Using the transceiver to respond to the trigger frame, sending a trigger-based physical layer protocol data unit PPDU to the infrastructure wireless communication terminal, switching an enhanced distributed channel access EDCA parameter set, which is a set of parameters for channel access, from a first EDCA parameter set to a second EDCA parameter set based on whether the infrastructure wireless communication terminal triggers the multi-user uplink transmission participation of the wireless communication terminal, When a media access control MAC protocol data unit MPDU included in the trigger-based PPDU requests an immediate response, when reception of the immediate response ends, setting a second EDCA parameter set timer, wherein the immediate response is ACK, When the MPDU included in the triggered PPDU does not request an immediate response, when transmission of the triggered PPDU ends, setting the second EDCA parameter set timer, When the second EDCA parameter set timer expires, terminating the application of the second EDCA parameter set, Calculate the random integer value in the contention window CW, setting a backoff timer based on the random integer value, and accessing a channel based on the backoff timer and a predetermined time slot time, The EDCA parameter set includes a minimum value CWmin of the CW and a maximum value CWmax of the CW.

2. The wireless communication terminal according to claim 1, wherein: The processor is configured to set the second EDCA parameter set timer for an access category of the MPDU to which the response is received.

3. The wireless communication terminal according to claim 1, wherein: The MPDU included in the trigger-based PPDU is a QoS data frame.

4. The wireless communication terminal according to claim 1, wherein: The processor is configured to receive a beacon frame from the infrastructure wireless communication terminal, and obtain information indicating a period of the second EDCA parameter set timer from the beacon frame.

5. The wireless communication terminal according to claim 1, wherein the processor is configured to in, When application of the second EDCA parameter set is terminated, the EDCA parameter set is switched from the second EDCA parameter set to the first EDCA parameter set, and if the value of the CW determined according to the priority of the data to be sent is greater than the CWmax of the first EDCA parameter set, the value of the CW is set to the CWmax of the first EDCA parameter set.

6. The wireless communication terminal according to claim 1, wherein: The processor is configured to: operate a plurality of queues classified according to access categories of data stored in the queues, and perform a backoff process of an access channel based on a time corresponding to a backoff timer of each of the plurality of queues, and When there is no data stored in the queue and the backoff timer corresponding to the queue is 0, no operation is performed at a time slot boundary of the backoff timer, The backoff timer is set based on a random integer value calculated in a contention window CW, and is reduced when the channel is idle within a predetermined time slot.

7. The wireless communication terminal according to claim 6, wherein: When there is no data stored in the queue and the backoff timer corresponding to the queue is 0, the processor is configured to maintain the backoff timer at 0.

8. A method for operating a wireless communication terminal for wirelessly communicating with an infrastructure wireless communication terminal, the method comprising: receiving a trigger frame from the basic wireless communication terminal; wherein the trigger frame triggers an orthogonal frequency division multiple access (OFDMA) uplink transmission in which a multi-user uplink transmission of the wireless communication terminal participates and allocates a resource unit to the wireless communication terminal, sending a triggered physical layer protocol data unit PPDU to the basic wireless communication terminal in response to the trigger frame, switching an enhanced distributed channel access EDCA parameter set, which is a set of parameters for channel access, from a first EDCA parameter set to a second EDCA parameter set based on whether the infrastructure wireless communication terminal triggers the multi-user uplink transmission participation of the wireless communication terminal, When a media access control MAC protocol data unit MPDU included in the trigger-based PPDU requests an immediate response, when reception of the immediate response ends, setting a second EDCA parameter set timer, wherein the immediate response is ACK, When the MPDU included in the trigger-based PPDU does not request an immediate response, when transmission of the trigger-based PPDU ends, setting a second EDCA parameter set timer, When the second EDCA parameter set timer expires, terminating the application of the second EDCA parameter set, Calculate the random integer value in the contention window CW, setting a backoff timer based on the random integer value, and accessing a channel based on the backoff timer and a predetermined time slot time, and sending the data via the channel, The EDCA parameter set includes a minimum value CWmin of the CW and a maximum value CWmax of the CW.

9. The method according to claim 8, wherein: The setting of the second EDCA parameter set timer includes: setting the second EDCA parameter set timer according to the access category of the MPDU to which the response is received.

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