Wireless communication method and its wireless communication terminal

Abstract

The present invention relates to a wireless communication method and a wireless communication terminal thereof, and more particularly, to a wireless communication method and a wireless communication terminal for setting various formats of an aggregated MPDU and its response frame and performing efficient data communication by using the same. To this end, the present invention provides a wireless communication terminal including: a processor; and a communication unit, wherein the processor generates an aggregated MPDU (A-MPDU) including one or more MAC protocol data units (MPDUs) requesting an immediate response, transmits the generated A-MPDU to a receiving party, receives a response frame corresponding to the A-MPDU from the receiving party, and determines whether the transmission of the MPDUs included in the A-MPDU is successful based on the received response frame. The present invention also provides a wireless communication method using the same.

Description

[0001] This application is a divisional application of the patent application with the application number 201780079155.0 (PCT / KR2017 / 015265), the international filing date of December 21, 2017, and the invention title of "Aggregated MPDU, Method for Transmitting Response Frame Thereto, and Wireless Communication Terminal Using the Same", which was filed with the Chinese Patent Office on June 20, 2019. Technical Field

[0002] The present invention relates to a method for transmitting an aggregated MPDU and its response frame, and a wireless communication terminal using the same, and more particularly, to a wireless communication method and a wireless communication terminal for setting various formats of the aggregated MPDU and its response frame and performing effective data communication by using the same. Background Art

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

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

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

[0006] As wireless LANs are actively provided and, further, the applications using wireless LANs are diversified, the demand for a new wireless LAN system that supports a higher throughput (Very High Throughput (VHT)) than the data processing speed supported by IEEE 802.11n has been drawing attention. Among them, IEEE 802.11ac supports a wide bandwidth (80 to 160 MHz) in the 5 GHz frequency band. The IEEE 802.11ac standard is defined only in the 5 GHz band, but the initial 11ac chipset even supports operation in the 2.4 GHz band for backward compatibility with existing 2.4 GHz band products. Theoretically, according to this standard, the wireless LAN speed of multiple stations can be enabled to reach at least 1 Gbps, and the maximum single-link speed can be enabled to reach at least 500 Mbps. This is achieved by expanding the concept of the wireless interface accepted by 802.11n, such as a wider wireless bandwidth (maximum 160 MHz), more MIMO spatial streams (maximum 8), multi-user MIMO, and high-density modulation (maximum 256QAM). In addition, as a scheme for transmitting data by using the 60 GHz band instead of the existing 2.4 GHz / 5 GHz, IEEE 802.11ad has been provided. IEEE 802.11ad is a transmission standard that provides a speed of up to 7 Gbps by using beamforming technology and is suitable for high-bitrate moving image streams such as massive data or uncompressed HD video. However, since the 60 GHz band has difficulty passing through obstacles, its drawback is that the 60 GHz band can only be used in devices in a short-distance space.

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

[0008] Technical problem

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

[0010] An object of the present invention is to set various formats of aggregated MPDUs and their response frames and use them to perform efficient data communication.

[0011] Technical solution

[0012] To achieve these objects, the present invention provides the following wireless communication method and wireless communication terminal.

[0013] First, an exemplary embodiment of the present invention provides a wireless communication terminal, including: a processor; and a communication unit, wherein the processor generates an aggregated MPDU (A-MPDU) including one or more MAC protocol data units (MPDUs) requesting an immediate response, sends the generated A-MPDU to a receiver, receives a response frame corresponding to the A-MPDU from the receiver, and determines whether the transmission of the MPDUs included in the A-MPDU is successful based on the received response frame.

[0014] The processor may determine whether the transmission of the MPDUs included in the A-MPDU is successful by considering the number of traffic identifiers (TIDs) requesting an immediate response or the MPDU delimiter information in one or more MPDUs constituting the A-MPDU and at least one in the response frame sent corresponding to the A-MPDU.

[0015] When the A-MPDU is composed of MPDUs of multiple TIDs requesting an immediate response and the response frame sent corresponding to the A-MPDU is an Ack frame, the processor may determine that the transmission of the MPDUs included in the A-MPDU has failed.

[0016] The processor may retransmit the MPDUs included in the A-MPDU determined that the transmission has failed.

[0017] The processor may determine that the channel access for the transmission of the A-MPDU is successful and reset at least one EDCA parameter of the access category for the channel access.

[0018] The response frame for the A-MPDU may be generated based on at least one of the number of TIDs requesting an immediate response in the MPDUs of the A-MPDU successfully received by the receiver or the MPDU delimiter information of the A-MPDU.

[0019] When the MPDU successfully received by the recipient includes only one MPDU that requests an immediate response, and the MPDU that requests an immediate response follows an MPDU delimiter having a value of the Frame End (EOF) field equal to 1 and a value of the MPDU length field not equal to 0, the response frame for the A-MPDU can be an Ack frame.

[0020] When the MPDU successfully received by the recipient includes one or more MPDUs of only one TID that request an immediate response, and the MPDU that requests an immediate response follows an MPDU delimiter having a value of the MPDU length field equal to 0, the response frame for the A-MPDU can be a compressed block Ack frame.

[0021] When the MPDU successfully received by the recipient includes MPDUs of multiple TIDs that request an immediate response or includes MPDUs of one or more TIDs that request an immediate response and action frames, the response frame for the A-MPDU can be a multi-STA block Ack frame.

[0022] When the recipient does not successfully receive at least one MPDU or MPDU delimiter in the A-MPDU, the response frame for the A-MPDU can be a multi-STA block Ack frame.

[0023] When at least one MPDU or MPDU delimiter is not successfully received before the first received EOF padding in the A-MPDU, the response frame for the A-MPDU can be a multi-STA block Ack frame.

[0024] When the recipient is able to send a multi-STA block Ack frame within the duration indicated by the successfully received MPDU or within the length indicated by the trigger information received from the A-MPDU, the recipient responds to the A-MPDU with a multi-STA block Ack frame.

[0025] In addition, an exemplary embodiment of the present invention provides a wireless communication method for a wireless communication terminal, including: generating an aggregated MPDU (A-MPDU) including one or more MAC protocol data units (MPDUs) that request an immediate response; sending the generated A-MPDU to a recipient; receiving, from the recipient, a response frame corresponding to the A-MPDU; and determining whether the transmission of the MPDUs included in the A-MPDU is successful based on the received response frame.

[0026] Next, another embodiment of the present invention provides a wireless communication terminal, including: a processor; and a communication unit, where the processor receives an aggregated MPDU (A-MPDU) composed of one or more MPDUs, determines the format of the response frame for the received A-MPDU, and sends a response frame of the determined format.

[0027] Determine the format of the response frame for the A-MPDU based on at least one of the number of TIDs in the successfully received MPDUs in the A-MPDU that request an immediate response and the MPDU delimiter information of the A-MPDU.

[0028] When the successfully received MPDU includes only one MPDU that requests an immediate response, and the MPDU that requests an immediate response follows an MPDU delimiter with a value of the Frame End (EOF) field equal to 1 and a value of the MPDU length field not equal to 0, the response frame for the A-MPDU can be determined as an Ack frame.

[0029] When the successfully received MPDUs include one or more MPDUs of only one TID that request an immediate response, and the MPDU that requests an immediate response follows an MPDU delimiter with a value of the MPDU length field equal to 0, the response frame for the A-MPDU can be determined as a compressed block Ack frame.

[0030] When the successfully received MPDUs include MPDUs of multiple TIDs that request an immediate response or include MPDUs of one or more TIDs that request an immediate response and action frames, the response frame for the A-MPDU can be determined as a multi-STA block Ack frame.

[0031] When the receiver does not successfully receive at least one MPDU or MPDU delimiter in the A-MPDU, the response frame for the A-MPDU can be a multi-STA block Ack frame.

[0032] When at least one MPDU or MPDU delimiter is not successfully received before the first received EOF padding in the A-MPDU, the response frame for the A-MPDU can be determined as a multi-STA block Ack frame.

[0033] When a multi-STA block Ack frame can be sent within the duration indicated by the successfully received MPDUs in the A-MPDU or within the length indicated by the trigger information received in the A-MPDU, the response frame for the A-MPDU can be determined as a multi-STA block Ack frame.

[0034] When the successfully received MPDU includes only one MPDU that requests an immediate response and a trigger frame, and the MPDU that requests an immediate response follows an MPDU delimiter with a value of the Frame End (EOF) field equal to 1 and a value of the MPDU length field not equal to 1, the response frame for the A-MPDU can be determined as an Ack frame.

[0035] In addition, another exemplary embodiment of the present invention provides a wireless communication method for a wireless communication terminal, including: receiving an aggregated MPDU (A-MPDU) composed of one or more MPDUs; determining a format of a response frame for the received A-MPDU; and transmitting the response frame in the determined format.

[0036] Advantageous Effects

[0037] According to an embodiment of the present invention, it is possible to set an aggregated MPDU and its response frame in various formats and perform efficient data communication.

[0038] According to an embodiment of the present invention, it is possible to increase the total resource utilization rate in a contention-based channel access system and improve the performance of a wireless LAN system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Illustrates a wireless LAN system according to an embodiment of the present invention.

[0040] Figure 2 Illustrates a wireless LAN system according to another embodiment of the present invention.

[0041] Figure 3 Illustrates a configuration of a station according to an embodiment of the present invention.

[0042] Figure 4 Illustrates a configuration of an access point according to an embodiment of the present invention.

[0043] Figure 5 Schematically illustrates a process in which a STA and an AP set a link.

[0044] Figure 6 Illustrates an embodiment of an MPDU aggregation method for a wireless LAN packet.

[0045] Figure 7 Illustrates an embodiment of an MPDU aggregation method for a wireless LAN packet in a non-traditional wireless LAN system.

[0046] Figure 8 Illustrates another embodiment of an MPDU aggregation method for a wireless LAN packet in a non-traditional wireless LAN system.

[0047] Figure 9 Illustrates yet another embodiment of an MPDU aggregation method for a wireless LAN packet in a non-traditional wireless LAN system.

[0048] Figure 10 Illustrates an embodiment of a response method according to the format of an A-MPDU.

[0049] Figure 11 Illustrates an embodiment of a method in which a terminal transmits a response frame for an A-MPDU.

[0050] Figure 12 Another embodiment of a method for a diagrammed terminal to send a response frame for an A-MPDU.

[0051] Figure 13 An embodiment of a method for a diagrammed AP to send a response frame for an A-MPDU.

[0052] Figure 14 A method for sending a response frame according to another embodiment of the present invention is diagrammed.

[0053] Figure 15 A method for sending an A-MPDU and a response frame according to an embodiment of the present invention is diagrammed.

[0054] Figure 16 A method for sending an A-MPDU and a response frame according to another embodiment of the present invention is diagrammed.

[0055] Figure 17 A method for sending an A-MPDU and a response frame according to yet another embodiment of the present invention is diagrammed.

[0056] Figure 18 A method for sending an S-MPDU and a response frame in a non-traditional wireless LAN system according to an embodiment of the present invention is diagrammed.

[0057] Figure 19 A method for sending an S-MPDU and a response frame in a non-traditional wireless LAN system according to another embodiment of the present invention is diagrammed.

[0058] Figure 20 An operation of a wireless communication terminal to send an A-MPDU based on the maximum number of TID information according to an embodiment of the present invention is diagrammed.

[0059] Figure 21 An operation of a wireless communication terminal to send an A-MPDU based on the maximum number of TID information according to another embodiment of the present invention is diagrammed.

[0060] Figure 22 An operation of a wireless communication terminal to send an A-MPDU based on the maximum number of TID information according to another embodiment of the present invention is diagrammed.

[0061] Figure 23 An operation of a wireless communication terminal to send an A-MPDU based on the maximum number of TID information according to another embodiment of the present invention is diagrammed.

[0062] Figure 24 An operation of a wireless communication terminal to set the maximum number of TID information of a trigger frame according to an embodiment of the present invention is diagrammed. Detailed Description

[0063] By considering the functions of the present invention, the terms used in this specification adopt the general terms that are currently widely used. However, the terms may change according to the intentions of those skilled in the art, customs, and the emergence of new technologies. In addition, in specific cases, there are terms arbitrarily selected by the applicant, and in such cases, their meanings will be described in the corresponding description part of the present invention. Therefore, it should be understood that the terms used in this specification should be analyzed not only based on the name of the term, but also based on the substantial meaning of the term and the content of the entire specification.

[0064] Throughout this specification and the following claims, when it describes that one element is "coupled" to another element, the element may be "directly coupled" to another element, or "electrically coupled" to another element via a third element. In addition, unless there is a clear contrary description, the word "comprising" and variations such as "including" or "includes" will be understood to implicitly include the stated elements, but do not exclude any other elements. In addition, limitations such as "or more" or "or less" based on a specific threshold may be appropriately replaced with "greater than" or "less than" respectively.

[0065] This application claims the priority and benefits of Korean Patent Applications 10-2016-0175999, 10-2017-0048145, and 10-2017-0146357 filed with the Korean Intellectual Property Office, and the embodiments and matters described in the corresponding applications that form the basis of the priority will be included in the detailed description of this application.

[0066] Figure 1 FIG. is a diagram illustrating a wireless LAN system according to an embodiment of the present invention. The wireless LAN system includes one or more basic service sets (BSSs), and a BSS represents a group of devices that have successfully synchronized with each other to communicate with each other. Generally, a BSS can be divided into an infrastructure BSS and an independent BSS (IBSS), and Figure 1 illustrates the infrastructure BSS between them.

[0067] As illustrated in Figure 1 the infrastructure BSSs (BSS1 and BSS2) include one or more stations STA1, STA2, STA3, STA4, and STA5, access points PCP / AP-1 and PCP / AP-2 of stations providing distributed services, and a distribution system (DS) connecting the multiple access points PCP / AP-1 and PCP / AP-2.

[0068] A station (STA) is a predefined device that includes a Media Access Control (MAC) compliant with the provisions of the IEEE 802.11 standard and a physical layer interface for a wireless medium, and generally includes both a non-access point (non-AP) station and an access point (AP). In addition, in this specification, the term "terminal" may be used to refer to a non-AP STA, or an AP, or both. A station for wireless communication includes a processor and a communication unit, and according to this embodiment, may further include a user interface unit and a display unit. The processor may generate a frame to be transmitted via a wireless network, or process a frame received via a wireless network, and in addition, perform various processes for controlling the station. In addition, the communication unit is functionally connected to the processor and transmits and receives frames via the wireless network for the station. According to the present invention, a terminal may be used as a term including a User Equipment (UE).

[0069] An access point (AP) is an entity that provides access to a Distribution System (DS) via a wireless medium for stations associated therewith. In an infrastructure BSS, communication among non-AP stations is in principle performed via the AP, but when a direct link is configured, direct communication among non-AP stations is even allowed. At the same time, in the present invention, the AP is used as a concept including a Personal BSS Coordination Point (PCP), and generally may include concepts including a central controller, a Base Station (BS), a Node B, a Base Station Transceiver System (BTS), and a Site Controller. In the present invention, the AP may also be referred to as a base station wireless communication terminal. The base station wireless communication terminal may be used as a term that generally includes an AP, a base station, an eNB (i.e., eNode B), and a Transmission Point (TP). In addition, the base station wireless communication terminal may include various types of wireless communication terminals that allocate media resources and perform scheduling for communicating with a plurality of wireless communication terminals.

[0070] Multiple infrastructure BSSs may be interconnected via a Distribution System (DS). In this case, the multiple BSSs connected via the distribution system are called an Extended Service Set (ESS).

[0071] Figure 2 FIG. illustrates a stand-alone BSS according to another embodiment of the present invention, which is a wireless LAN system. In Figure 2 the embodiment, a repeated description of the same or corresponding parts of Figure 1 the embodiment will be omitted.

[0072] Since the BSS3 illustrated in Figure 2 is a stand-alone BSS and does not include an AP, all stations STA6 and STA7 are not connected to the AP. A stand-alone BSS is not allowed to access the distribution system and forms a self-contained network. In a stand-alone BSS, the corresponding stations STA6 and STA7 may be directly connected to each other.

[0073] Figure 3 is a block diagram illustrating the configuration of a station 100 according to an embodiment of the present invention. As illustrated in Figure 3 FIG. 1, the station 100 according to an embodiment of the present invention may include a processor 110, a communication unit 120, a user interface unit 140, a display unit 150, and a memory 160.

[0074] First, the communication unit 120 transmits and receives wireless signals, such as wireless LAN packets and the like, and may be embedded in the station 100 or provided as a peripheral device. According to this embodiment, the communication unit 120 may include at least one communication module using different frequency bands. For example, the communication unit 120 may include communication modules having different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. According to one embodiment, the station 100 may include a communication module using a frequency band of 6 GHz or higher and a communication module using a frequency band of 6 GHz or lower. The corresponding communication module may perform wireless communication with an AP or an external station according to the wireless LAN standard of the frequency band supported by the corresponding communication module. The communication unit 120 may operate only one communication module at a certain time or operate multiple communication modules together simultaneously according to the performance and requirements of the station 100. When the station 100 includes multiple communication modules, each communication module may be implemented by independent components, or multiple modules may be integrated into one chip. In an embodiment of the present invention, the communication unit 120 may represent a radio frequency (RF) communication module for processing RF signals.

[0075] Second, the user interface unit 140 includes various types of input / output devices provided in the station 100. That is, the user interface unit 140 may receive user input by using various input devices, and the processor 110 may control the station 100 based on the received user input. In addition, the user interface unit 140 may perform output based on the command of the processor 110 by using various output devices.

[0076] Next, the display unit 150 outputs an image on a display screen. The display unit 150 may output various display objects, such as the content executed by the processor 110 or the user interface and the like, based on the control command of the processor 110. In addition, the memory 160 stores control programs and various result data used in the station 100. The control program may include an access program required for the station 100 to access an AP or an external station.

[0077] 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 each unit of the station 100 and control data transmission / reception among the units. According to an embodiment of the present invention, the processor 110 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 the main control unit of the station 100, and according to this embodiment, the processor 110 may represent a control unit for separately controlling certain components of the station 100, such as the communication unit 120 and the like. That is, the processor 110 may be a modem or a modulator / demodulator for modulating a wireless signal sent to the communication unit 120 and demodulating a wireless signal received from the communication unit 120. The processor 110 controls various operations of the wireless signal transmission / reception of the station 100 according to an embodiment of the present invention. Its detailed embodiments will be described below.

[0078] In Figure 3 The station 100 illustrated is a block diagram according to an embodiment of the present invention, where individual blocks are illustrated as elements of logically distinct devices. Therefore, the elements of the device may be installed in a single chip or multiple chips according to the design of the device. For example, the processor 110 and the communication unit 120 may be implemented when integrated into a single chip or as separate chips. In addition, in an embodiment of the present invention, certain components of the station 100, such as the user interface unit 140 and the display unit 150, may be selectively provided in the station 100.

[0079] Figure 4 is a block diagram illustrating the configuration of an AP 200 according to an embodiment of the present invention. As illustrated in Figure 4 The AP 200 according to an embodiment of the present invention may include a processor 210, a communication unit 220, and a memory 260. In Figure 4 Among the components of the AP200, a repeated description of parts that are the same as or correspond to Figure 2 the components of the station 100 of Figure 2 will be omitted.

[0080] Referring to Figure 4 According to the present invention, the AP 200 includes a communication unit 220 that operates a BSS in at least one frequency band. As in Figure 3As described in the embodiments, the communication unit 220 of the AP 200 may also include a plurality of communication modules using different frequency bands. That is, the AP 200 according to an embodiment of the present invention may include two or more communication modules in different frequency bands, such as 2.4 GHz, 5 GHz, and 60 GHz. Preferably, the AP 200 may include a communication module using a frequency band of 6 GHz or higher and a communication module using a frequency band of 6 GHz or lower. Each communication module may perform wireless communication with a station according to the wireless LAN standard of the frequency band supported by the corresponding communication module. The communication unit 220 may operate only one communication module at a certain time or operate a plurality of communication modules together simultaneously according to the performance and requirements of the AP 200. In an embodiment of the present invention, the communication unit 220 may represent a radio frequency (RF) communication module for processing RF signals.

[0081] Next, the memory 260 stores control programs and various result data used in the AP 200. The control program may include an access program for managing access of stations. In addition, the processor 210 may control each unit of the AP 200 and control data transmission / reception among the units. According to an embodiment of the present invention, the processor 210 may execute a program for accessing stations stored in the memory 260 and send communication configuration messages for one or more stations. In this case, the communication configuration message may include information about access priority conditions of each station. In addition, the processor 210 performs access configuration according to an access request of a station. According to one embodiment, the processor 210 may be a modem or a modulator / demodulator for modulating a wireless signal transmitted to the communication unit 220 and demodulating a wireless signal received from the communication unit 220. The processor 210 controls various operations such as wireless signal transmission / reception of the AP 200 according to an embodiment of the present invention. Detailed embodiments thereof will be described below.

[0082] Figure 5 is a diagram schematically illustrating a process of setting a link between a STA and an AP.

[0083] Reference Figure 5 , generally, a link between the STA 100 and the AP 200 is set via three steps of scanning, authentication, and association. First, the scanning step is a step in which the STA 100 obtains access information of a BSS operated by the AP 200. Methods for performing scanning include a passive scanning method in which the AP 200 obtains information by using beacon messages (S101) periodically transmitted, and an active scanning method in which the STA 100 sends a probe request to the AP (S103) and obtains access information by receiving a probe response from the AP (S105).

[0084] The STA 100 that has successfully received wireless access information in the scanning step performs an authentication step (S107b) by sending an authentication request (S107a) and receiving an authentication response from the AP 200. After performing the authentication step, the STA 100 performs an association step by sending an association request (S109a) and receiving an association response (S109b) from the AP 200. In this specification, association basically refers to wireless association. However, the present invention is not limited thereto, and association can broadly include both wireless association and wired association.

[0085] Meanwhile, an 802.1X-based authentication step (S111) and an IP address acquisition step via DHCP (S113) can be additionally performed. In Figure 5 this case, the authentication server 300 is a server that processes 802.1X-based authentication of the STA 100, and can exist in a physical association with the AP 200 or exist as a separate server.

[0086] Aggregated MPDU (A-MPDU)

[0087] Figure 6 An embodiment of a method for aggregating MAC protocol data units (MPDUs) of wireless LAN packets is illustrated. In a contention-based wireless LAN system, a terminal must perform contention for channel occupancy every time it attempts to send data. Therefore, as the density of terminals in the BSS and the amount of transmitted data per terminal increase, the efficiency of the actual data transmission amount compared to the contention time may be greatly reduced.

[0088] To solve such problems and improve the data transmission efficiency of terminals, as Figure 6 illustrated herein, aggregated MPDUs (A-MPDUs) can be used. An A-MPDU consists of one or more A-MPDU subframes and a variable number of frame end (EOF) paddings in this order. Each A-MPDU subframe can contain an MPDU delimiter and optionally an MPDU following it. The MPDU delimiter indicates information about the MPDU contained in the corresponding A-MPDU subframe. More specifically, the MPDU delimiter contains a frame end (EOF) field, an MPDU length field, a cyclic redundancy check (CRC) field, and an MPDU signature field. The EOF length field indicates the length of the MPDU. If there is no MPDU in the A-MPDU subframe, the MPDU length field is set to 0. In addition, the CRC field is used to detect errors in the MPDU delimiter, and the MPDU signature field represents a pattern that the receiving party can use to detect the MPDU delimiter.

[0089] In the following, in embodiments of the present invention, for convenience, an MPDU may also be used as a term indicating an A-MPDU subframe composed of the corresponding MPDUs. For example, an MPDU having a value of the EOF field set to 1 may indicate an A-MPDU subframe having a value of the EOF field set to 1 or an MPDU constituting the A-MPDU subframe. More specifically, an MPDU having a value of the EOF field set to 1 may indicate an A-MPDU subframe including an MPDU delimiter having a value of the EOF field set to 1, or an MPDU constituting the A-MPDU subframe. Further, in embodiments of the present invention, a recipient may be used as a term indicating a terminal that receives an A-MPDU and sends a response frame thereto.

[0090] Figure 6 (a) illustrates an embodiment of the configuration of an A-MPDU. As illustrated, an A-MPDU may include one or more A-MPDU subframes (i.e., pre-EOF padding portions) and an EOF padding portion. In the case of a traffic ID (TID) for which a block acknowledgment (BA) convention has been performed, a plurality of data frames (or data MPDUs) may be sent together via a single A-MPDU. In this case, in the MPDU delimiter for each MPDU, the value of the EOF field is set to 0 and the value of the MPDU length field is set to a non-zero value. Referring to FIG. Figure 6 (a), a plurality of data MPDUs belonging to TID2 are sent via a single A-MPDU. In the EOF padding portion immediately following the pre-EOF padding portion, one or more EOF delimiters having a value of the EOF field set to 1 and a value of the MPDU length field set to 0 are sent to indicate the end of the A-MPDU transmission.

[0091] Figure 6(b) An example of the structure of a single MPDU (S-MPDU) is shown. If the transmitter intends to send an MPDU, the above configuration of the A-MPDU may be inefficient. More specifically, if the A-MPDU is used, an MPDU delimiter should be inserted for each MPDU, and a block Ack-based response including a BA bitmap may be requested. At the same time, in the 802.11ac wireless LAN system, all data transmitted in the PHY protocol data unit (PPDU) format of the VHT PPDU is defined to be transmitted in the MPDU format of the A-MPDU. Therefore, in order to improve the inefficient transmission structure in the above case, when only one MPDU is transmitted in the PPDU, the S-MPDU format can be used. In the MPDU delimiter of the data MPDU transmitted only in the S-MPDU format, the value of the EOF field is set to 1 and the value of the MPDU length field is set to a non-zero value. Similar to the A-MPDU format, EOF padding can also be used in the S-MPDU format. When an S-MPDU is received, regardless of whether a block Ack agreement has been executed between the transmitter and the receiver, the receiver can respond with a normal Ack instead of a block Ack.

[0092] Figure 7 An example of an MPDU aggregation method for wireless LAN packets in a non-traditional wireless LAN system is shown. In an embodiment of the present invention, the non-traditional wireless LAN system may refer to a wireless LAN system compliant with the IEEE 802.11ax standard, and the non-traditional wireless LAN packet may refer to a high-efficiency (HE) PPDU compliant with this standard. However, the present invention is not limited thereto.

[0093] In traditional wireless LAN systems prior to the IEEE 802.11ax standard, there is a limitation that all MPDUs included in an A-MPDU should belong to the same TID. For example, a data MPDU and an action frame cannot be aggregated into a single A-MPDU. Additionally, since MPDUs with different TIDs cannot be included in an A-MPDU, if a data MPDU with an EOF field value of 1 is included in the received A-MPDU, the receiving party will recognize the corresponding data MPDU as the only MPDU included in the A-MPDU. Therefore, the receiving party can regard the A-MPDU as an S-MPDU and respond with a generic Ack.

[0094] However, in a non - traditional wireless LAN system, an A - MPDU that aggregates multiple MPDUs with multiple TIDs can be sent in the case of multi - user (MU) transmission or single - user (SU) transmission that meets specific conditions. In this way, an A - MPDU that aggregates multiple MPDUs with multiple TIDs is called a multi - TID A - MPDU. The multi - TID A - MPDU of a non - traditional wireless LAN system can include one or more A - MPDU sub - frames having a value of the EOF field set to 1.

[0095] Each MPDU of one or more A - MPDU sub - frames having a value of the EOF field set to 1 should belong to a different TID and should be the only MPDU of the corresponding TID in the A - MPDU. That is, an A - MPDU sub - frame containing an MPDU delimiter with a value of the EOF field set to 1 consists of an MPDU or an action frame that requests a general Ack response. As Figure 7 (a) illustrated, the value of the EOF field of the MPDU delimiter before the only MPDU of a specific TID in the A - MPDU (i.e., the MPDU of TID1 and the MPDU of TID3) can be set to 1. Here, even in the case of a QoS data MPDU of a TID for which block Ack agreement has been executed, when the MPDU is the only MPDU of the TID in the A - MPDU, the value of the EOF field of the MPDU delimiter is set to 1. Additionally, as Figure 7 (b) illustrated, an action frame that requests a general Ack response can also be aggregated with other data MPDUs. In this case, at most one action frame can be aggregated in the A - MPDU, and the value of the EOF field of the MPDU delimiter before the action frame can be set to 1.

[0096] On the other hand, by setting the value of the EOF field of the corresponding MPDU delimiter to 1, data MPDUs of a TID for which block Ack agreement is not performed can be aggregated together with data MPDUs of another TID. If block Ack agreement is not performed, frames of the corresponding TID basically do not support responses to block Ack. However, since multi-STA block Ack (hereinafter, M-BA) supports an Ack context, it is possible to use M-BA to perform a response to the MPDUs of the corresponding TID. If a data MPDU of a TID for which block Ack agreement is not performed is transmitted via an A-MPDU, it is obvious that the MPDU is the only MPDU of the corresponding TID. Therefore, according to an embodiment of the present invention, when a data MPDU of a TID for which block Ack agreement is not performed is transmitted via an A-MPDU, the value of the EOF field of the corresponding MPDU delimiter can be set to 0. However, even in this case, when one or more other MPDUs aggregated in the A-MPDU request an immediate response, M-BA can be used to perform a response to the MPDUs of the corresponding TID.

[0097] In addition, by setting the value of the EOF field of the corresponding MPDU delimiter to 0, one or more MPDUs of a TID for which block Ack agreement has been performed can be aggregated into the same A-MPDU. That is, one or more A-MPDU sub-frames having a value of the EOF field equal to 0 can be aggregated together with an A-MPDU sub-frame having a value of the EOF field equal to 1. In a conventional wireless LAN system, when the value of the EOF field of the first MPDU delimiter of a received A-MPDU is 1, the MPDU of the corresponding A-MPDU sub-frame can be regarded as the only MPDU transmitted via the A-MPDU. That is, the received A-MPDU can be regarded as Figure 7 (c) the S-MPDU illustrated in. However, in a non-conventional wireless LAN system, after identifying subsequent MPDU delimiters and MPDUs, it is possible to determine whether the A-MPDU is an S-MPDU, a (single-TID) A-MPDU, or a multi-TID A-MPDU.

[0098] The recipient of the above S-MPDU, A-MPDU, or multi-TID A-MPDU may send a response based on the acknowledgment context. According to an embodiment of the present invention, the acknowledgment context may include a block Ack context, an Ack context, an all-Ack context, etc., and specific embodiments thereof will be described later. According to an embodiment of the present invention, an A-MPDU subframe in which the value of the EOF field is set to 1 may indicate an Ack context. If an MPDU of an A-MPDU subframe having a value of the EOF field equal to 1 is sent individually via the A-MPDU, an Ack frame may be used to perform a response to the corresponding MPDU. However, if an MPDU of an A-MPDU subframe having a value of the EOF field equal to 1 is aggregated and sent together with other frames requesting an immediate response, an M-BA frame may be used to perform a response to the corresponding MPDU.

[0099] When using an M-BA frame to perform a response to an MPDU of an A-MPDU subframe having a value of the EOF field equal to 1, a response to the MPDU is received through each AID TID information field, where the BA bitmap is omitted from the M-BA. More specifically, the acknowledgment context included in each AID TID information in the M-BA frame may be indicated via the Ack type subfield in each AID TID information field. According to an embodiment, a value of the Ack type subfield equal to 1 may indicate an Ack context, and a value of the Ack type subfield equal to 0 may indicate a block Ack context. Therefore, when using an M-BA frame to perform a response to an MPDU of an A-MPDU subframe having a value of the EOF field equal to 1, a response to the MPDU may be received through each AID TID information field, where the value of the Ack type subfield is set to 1. That is, the value of the Ack type subfield of each AID TID information field including the response information for the MPDU (i.e., Ack type subfield = 1) is set to be different from the value of the Ack type subfield of each other AID TID information field requesting the BA bitmap (i.e., Ack type subfield = 0).

[0100] Figure 8 Another embodiment of an MPDU aggregation method for wireless LAN packets in a non-traditional wireless LAN system is illustrated. As described above, since multi-TID A-MPDUs are used in a non-traditional wireless LAN system, there may be at most one A-MPDU subframe in which the value of the EOF field is set to 1 for each TID in an A-MPDU. That is, in an A-MPDU, an A-MPDU subframe in which the value of the EOF field is set to 1 and multiple A-MPDU subframes in which the value of the EOF field is set to 0 may coexist.

[0101] In a single-TID A-MPDU used in a traditional wireless LAN system, an MPDU delimiter having an EOF value equal to 0 cannot follow an MPDU delimiter having an EOF value equal to 1. However, in a multi-TID A-MPDU used in a non-traditional wireless LAN system, since A-MPDU subframes having an EOF field value equal to 0 and A-MPDU subframes having an EOF field value equal to 1 are mixed, the EOF values of the MPDU delimiters can be randomly arranged. According to an embodiment of the present invention, the arrangement method of multiple MPDUs in a multi-TID A-MPDU can be configured to conform to the traditional MPDU arrangement rules in the A-MPDU.

[0102] More specifically, according to an embodiment of the present invention, an A-MPDU subframe in which the value of the EOF field is set to 1 can be set to be located between an A-MPDU subframe in which the value of the EOF field is set to 0 and an EOF padding. More specifically, the arrangement of the MPDU delimiters (or A-MPDU subframes) in the A-MPDU can be set in the following order.

[0103] First group: MPDU delimiter ( Figure 8 the MPDU delimiter of the MPDU of TID2 in the embodiment of

[0104] ), in which the value of the EOF field is set to 0 and the value of the MPDU length field is set to a non-zero value. Figure 8 Second group: MPDU delimiters (the MPDU delimiter for the MPDU of TID1, the MPDU delimiter for the MPDU of TID3, and the MPDU delimiter for

[0105] the action frame in the embodiment of Figure 8 ), in which the value of the EOF field is set to 1 and the value of the MPDU length field is set to a non-zero value.

[0106] Third group: MPDU delimiter (

[0107] Figure 9 Figure 8 the EOF padding part in the embodiment of

[0106] ), in which the value of the EOF field is set to 1 and the value of the MPDU length field is set to 0.

[0107] Figure 9 That is, the arrangement of the MPDU delimiters in the A-MPDU can be set in the order of the first group, the second group, and the third group. According to an embodiment, there can be no additional restrictions on the arrangement order of the MPDUs within the first group and / or the arrangement order of the MPDUs within the second group. That is, the arrangement of multiple MPDUs belonging to the same group may not be consecutive for each same TID, and the order of the TIDs may not be restricted.

[0107] Figure 9Another embodiment of the MPDU aggregation method for wireless LAN packets in a non - traditional wireless LAN system is illustrated. An A - MPDU can aggregate multiple MPDUs into one PHY service data unit (PPDU). In this case, MPDUs of various frames can be aggregated into an A - MPDU. More specifically, QoS data frames, QoS null frames, action frames, action frames without Ack, control frames, etc. can be aggregated into one A - MPDU. Among them, according to whether the data frame requests an immediate response, the A - MPDU containing the QoS data frame can be classified into a data - enabled immediate response (DEIR) context and a data - enabled no - immediate response (DENIR) context.

[0108] Whether a data frame requests an immediate response can be indicated by the Ack policy sub - field in the QoS control field of the MAC header. According to an embodiment, the Ack policy sub - field can indicate the acknowledgment policy of the data via four different field values.

[0109] First, if the Ack policy sub - field is set to a first value, the receiver responds to the data frame with a generic Ack or an implicit block Ack. If the acknowledgment policy is a generic Ack or an implicit block Ack, the data frame requests an immediate response. That is, the receiver sends an Ack frame or a block Ack frame as SIFS after the PPDU carrying the data frame. In this case, the block Ack frame can be sent separately or as part of the A - MPDU.

[0110] Next, when the Ack policy sub - field is set to a second value, no response is requested for the corresponding data frame. That is, when the Ack policy sub - field is set to the second value, the acknowledgment policy can be recognized as no - Ack.

[0111] Next, when the Ack policy sub - field is set to a third value, a non - explicit Ack is requested. If the acknowledgment policy is a non - explicit Ack, a response to the data frame is performed, but the response is not an Ack frame. According to another embodiment of the present invention, if the Ack policy sub - field is set to the third value, a HE TB PPDU (HTP) Ack can be requested. If a data frame is sent through a PPDU that requests a high - efficiency trigger - based (HE TB) PPDU and the acknowledgment policy of the data frame is an HTP Ack, the receiver responds to the data frame through an HE TB PPDU.

[0112] Finally, if the Ack policy sub - field is set to a fourth value, a block Ack is requested. If the acknowledgment policy is a block Ack, the receiver does not take any action except recording its state when the frame is received. When a block Ack request frame is received, the receiver can perform a response.

[0113] Information indicating whether a data frame requests an immediate response is specified in the form of QoSAck or QosNoAck for each service class of each TID in a MAC service access point (SAP) that is part of the upper layer of the MAC. In a TID where the service class is specified as QoSNoAck, the block Ack convention is not performed, and the value of the Ack policy subfield of the frame of the corresponding TID is set to indicate a second value, i.e., no Ack.

[0114] In a traditional wireless LAN system, an MPDU of only one TID can be sent through one A-MPDU. Therefore, when aggregating QoS data frames or QoS null frames of TIDs that request immediate response, the corresponding A-MPDU is automatically classified as a DEIR context. Additionally, when aggregating QoS data frames or QoS null frames of TIDs that do not request immediate response, the corresponding A-MPDU is automatically classified as a DENIR context. Thus, in a traditional wireless LAN system, frames of a TID with a service class of QoSAck and frames of another TID with a service class of QoSNoAck cannot be aggregated into one A-MPDU. However, in a non-traditional wireless LAN system, aggregation of MPDUs of different TIDs through a multi-TID A-MPDU is allowed. Therefore, in a non-traditional wireless LAN system, it is necessary to modify the context of the A-MPDU in which frames of a TID with a service class of QoSAck and frames of another TID with a service class of QoSNoAck are aggregated together.

[0115] First, Figure 9 (a) shows an A-MPDU of a DEIR context according to an embodiment of the present invention. An A-MPDU in which frames of a TID with a service class of QoSAck and frames of another TID with a service class of QoSNoAck are aggregated can be classified as a DEIR context because an immediate response is requested through the TID whose service class is QoSAck. According to an embodiment of the present invention, even if at least one of a frame whose acknowledgment policy is Ack (or implicit block Ack), a frame whose acknowledgment policy is HTP Ack, a frame whose acknowledgment policy is block Ack, and an action frame exists in the A-MPDU, frames with an acknowledgment policy of no Ack can be selectively aggregated into the A-MPDU of the DEIR context.

[0116] Next, Figure 9 (b) shows an A-MPDU of a DENIR context according to an embodiment of the present invention. According to an embodiment of the present invention, frames of multiple TIDs with an acknowledgment policy of no Ack can be aggregated together in the A-MPDU of the DENIR context. Additionally, frames of one or more TIDs with an acknowledgment policy of no Ack and action no Ack frames can be aggregated together in the A-MPDU of the DENIR context.

[0117] Response Frame for A-MPDU

[0118] Figure 10 FIG. illustrates an embodiment of a response method according to the format of an A-MPDU. As described above, in a non-traditional wireless LAN system, an A-MPDU having the following format can be used. i) An A-MPDU that aggregates multiple MPDUs belonging to different TIDs ( Figure 10 (embodiment of (a)). ii) An A-MPDU that aggregates multiple MPDUs belonging to a single TID ( Figure 10 (embodiment of (b)). iii) An A-MPDU that contains a single MPDU ( Figure 10 (embodiment of (c)).

[0119] Therefore, the structure of the response frame can vary according to the format of the A-MPDU received by the recipient. According to an embodiment of the present invention, the following response frames can be sent for each format of the A-MPDU.

[0120] 1) Ack frame: If there is only one MPDU in the received A-MPDU whose EOF field value is set to 1. Alternatively, if there is only one MPDU that requests an immediate response in the received A-MPDU.

[0121] 2) Compressed Block Ack (C-BA) frame: Among the received A-MPDUs, if the MPDUs that request an immediate response belong to the same TID. Alternatively, if the received A-MPDU consists only of one TID MPDU that requests an immediate response and frames of other TIDs that do not request an immediate response. In this case, the frames that do not request an immediate response can include action no-Ack frames, QoS data frames whose acknowledgment policy is block Ack or no-Ack, QoS null frames whose acknowledgment policy is block Ack or no-Ack, and so on.

[0122] 3) Multi-STA Block Ack (M-BA) frame: If the received A-MPDU consists of MPDUs of two or more TIDs that request an immediate response. Alternatively, if the received A-MPDU is configured to include MPDUs of one or more TIDs that request an immediate response and action frames. When sending a response via the M-BA frame, the response can be performed via each AID TID information field, which is independent for each TID. If there is an MPDU in the received A-MPDU whose EOF field value is set to 1, the value of the Ack type subfield of each AID TID information field corresponding to the MPDU can be set to 1, so that the BA bitmap is omitted.

[0123] Figure 11An embodiment of a method for a diagrammatic terminal to send a response frame for an A-MPDU is illustrated. As described above, in a non-conventional wireless LAN system, a transmitter can send a multi-TID A-MPDU and can specify different response strategies for each TID in an A-MPDU. Additionally, a receiver can use an Ack frame, a block Ack frame, or an M-BA frame to send a response based on the format of the received A-MPDU. Different from an AP, a non-AP STA cannot receive data from multiple terminals simultaneously. Therefore, the STA can execute a response to the A-MPDU based on information included in the received A-MPDU, the presence of uplink multi-user trigger information in the A-MPDU, etc.

[0124] Figure 11 An embodiment of a response method of an STA when there is no MPDU with a response strategy set to HTP Ack in a received A-MPDU is illustrated. The A-MPDU sent by an AP can be carried via a High-Efficiency Single-User (HE SU) PPDU or a High-Efficiency Multi-User (HE MU) PPDU, and the STA receives the PPDU. If the response strategy of the MPDU included in the received A-MPDU is set to HTP Ack, the receiver should execute a response in the HE-TB PPDU format. However, if there is no MPDU with a response strategy set to HTP Ack in the received A-MPDU, the STA can execute a response in the HE SU PPDU format.

[0125] In this case, the STA can respond with an Ack frame, a block Ack frame, or an M-BA frame carried in the HE SU PPDU based on the format of the received A-MPDU. According to an embodiment, the STA can determine the format of the response frame considering the number of TIDs requesting an immediate response, the MPDU delimiter information of the MPDUs in the successfully received A-MPDU, etc. in the MPDUs of the successfully received A-MPDU. More specifically, the STA can determine the format of the response frame based on a combination of at least one of the following information included in the successfully received MPDUs in the A-MPDU. i) The number of TIDs requesting an immediate response, ii) The presence or number of MPDU delimiters with an EOF field value equal to 1 and an MPDU length field value not equal to 1, iii) The number of MPDUs requesting a response in an Ack context, and iv) The number of MPDUs without a block Ack convention.

[0126] First, Figure 11(a) Illustrates an embodiment in which the STA responds to an A-MPDU through an Ack frame carried in a HE SU PPDU. According to an embodiment of the present invention, if the MPDU successfully received in the A-MPDU is the only MPDU that immediately requests an Ack context response (i.e., the received A-MPDU is identified as an S-MPDU), the STA responds through an Ack frame. Moreover, if the MPDU successfully received in the A-MPDU includes only one MPDU that immediately requests an Ack context response and one or more other MPDUs that do not request an immediate response, the STA responds through an Ack frame. That is, if the MPDU successfully received in the A-MPDU includes only one MPDU that requests an immediate response, the STA responds through an Ack frame.

[0127] In this case, the MPDU that immediately requests an Ack context response may include an action frame, a QoS data frame in which the acknowledgment policy is general Ack, a QoS null frame in which the acknowledgment policy is general Ack, and so on. According to an embodiment of the present invention, the MPDU that immediately requests an Ack context response may follow an MPDU delimiter with a value of the EOF field equal to 1 and a value of the MPDU length field not equal to 0. The MPDUs that do not request an immediate response may include an action no Ack frame, a QoS data frame in which the acknowledgment policy is block Ack or no Ack, a QoS null frame in which the acknowledgment policy is block Ack or no Ack, etc.

[0128] According to another embodiment of the present invention, if the received A-MPDU is identified as including only one MPDU that immediately requests an Ack context response, the STA may respond with an M-BA frame. In this case, the STA may insert only one per AID TID information field in the M-BA frame to perform the response of the Ack context. However, since the length of the M-BA frame is longer than the length of the Ack frame, the STA may respond with an M-BA frame only when it can be transmitted according to the specified rules using a modulation and coding scheme (MCS) within the duration indicated by the received MPDU.

[0129] Next, Figure 11(b) Illustrates an embodiment in which the STA uses a Compressed Block Ack (C-BA) frame carried in the HE SU PPDU to respond to an A-MPDU. According to an embodiment of the present invention, when the received A-MPDU is recognized as a single-TID A-MPDU, the STA responds with a Compressed Block Ack (C-BA) frame. That is, if the successfully received MPDUs in the A-MPDU include one or more MPDUs of only one TID that request an immediate response, the STA responds with a C-BA frame. Moreover, if the successfully received MPDUs in the A-MPDU include one or more MPDUs of only one TID that request an immediate response and one or more other MPDUs that do not request an immediate response, the STA responds with a C-BA frame. In other words, if all the MPDUs that request an immediate response in the MPDUs of the successfully received A-MPDU belong to the same TID, the STA responds with a C-BA frame.

[0130] In this case, the MPDUs that request an immediate response may include QoS data frames in which the acknowledgment policy is implicit block Ack, QoS null frames in which the acknowledgment policy is implicit block Ack, and so on. According to an embodiment of the present invention, a frame in which the acknowledgment policy is implicit block Ack may request an immediate response of the block Ack context. According to one embodiment, an MPDU that requests an immediate response of the block Ack context may follow an MPDU delimiter with a value of the EOF field equal to 0 and a value of the MPDU length field not equal to 0. In addition, the MPDUs that do not request an immediate response may include action no Ack frames, QoS data frames in which the acknowledgment policy is block Ack or no Ack, QoS null frames in which the acknowledgment policy is block Ack or no Ack, etc. According to another embodiment of the present invention, if the received A-MPDU is recognized as a single-TID A-MPDU, the STA may also respond with an M-BA frame.

[0131] Next, Figure 11 (c) Illustrates an embodiment in which the STA responds to an A-MPDU by using a Multi-STA Block Ack (M-BA) frame carried in the HE SU PPDU.

[0132] According to an embodiment of the present invention, when the received A-MPDU is recognized as a multi-TID A-MPDU, the STA responds with a Multi-STA Block Ack (M-BA) frame. That is, if the successfully received MPDUs in the A-MPDU include MPDUs of two or more TIDs that request an immediate response, the STA responds with an M-BA frame. Moreover, if the successfully received MPDUs in the A-MPDU include MPDUs of one or more TIDs that request an immediate response and action frames, the STA responds with an M-BA frame.

[0133] According to yet another specific embodiment, if the received A-MPDU satisfies at least one of the following conditions, the STA may respond with an M-BA frame: i) The A-MPDU contains MPDUs of two or more TIDs that request an immediate response of the block Ack context. ii) The A-MPDU contains MPDUs of one or more TIDs that request an immediate response of the block Ack context and MPDUs of one or more TIDs that request an immediate response of the Ack context. iii) The A-MPDU contains MPDUs of two or more TIDs that request an immediate response of the Ack context. iv) The A-MPDU contains MPDUs of one or more TIDs that request an immediate response of the block Ack context or the Ack context and action frames.

[0134] In this case, the MPDUs that request an immediate response of the block Ack context may include QoS data frames in which the acknowledgment strategy is implicit block Ack, QoS null frames in which the acknowledgment strategy is implicit block Ack, and so on. According to one embodiment, the MPDUs that request an immediate response of the block Ack context may follow an MPDU delimiter with a value of 0 for the EOF field and a non-zero value for the MPDU length field. In addition, the MPDUs that request a response of the immediate Ack context may include action frames, QoS data frames in which the acknowledgment strategy is general Ack, QoS null frames in which the acknowledgment strategy is general Ack, etc. According to an embodiment of the present invention, the MPDUs that request an immediate response of the Ack context may follow an MPDU delimiter with a value of 1 for the EOF field and a non-zero value for the MPDU length field.

[0135] When sending a response via an M-BA frame, the response may be performed through the per-AID TID information field that is independent for each TID. In this case, in the response to an action frame, the TID value of the per-AID TID information field is set to "1111". If there is an MPDU of the Ack context in the received A-MPDU, the value of the Ack type subfield of the per-AID TID information field corresponding to the MPDU may be set to 1 so that the BA bitmap is omitted. In addition, if all MPDUs included in the received A-MPDU are successfully received, the STA may perform the response to all Ack contexts by inserting only one per-AID TID information field in the M-BA frame. In this case, the TID value of the only one per-AID TID information field inserted in the M-BA frame may be set to "1110" to indicate the response to all Ack contexts.

[0136] Figure 12 Another embodiment of a method for a diagrammatic terminal to send a response frame for an A-MPDU is shown. In Figure 12In the embodiments, parts that are the same as or corresponding to the above Figure 11 embodiments will be omitted.

[0137] Figure 12 Embodiments of a method for a STA to respond when there is an MPDU with an acknowledgment policy set to HTP Ack in a received A-MPDU are illustrated. The A-MPDU sent by the AP may be carried via a High-Efficiency Single-User (HE SU) PPDU or a High-Efficiency Multi-User (HE MU) PPDU, and the STA receives the PPDU. If the acknowledgment policy of the MPDU included in the received A-MPDU is set to HTP Ack, the receiver should perform a response in the HE-TB PPDU format. In this case, only when the following conditions are met can the STA that receives the MPDU with the acknowledgment policy set to HTP Ack respond in the HE TB PPDU format. i) When receiving an A-MPDU that contains a trigger frame in which the receiver address field is set to the address of the STA. ii) When receiving an A-MPDU that contains a QoS data frame or a QoS null frame, which includes an Uplink Multi-User Response Scheduling (UMRS) control field and the receiver address field is set to the address of the STA. If at least one of the trigger frame and the UMRS control field is not received, the STA cannot respond to the MPDU with the acknowledgment policy set to HTP Ack. The STA may respond with an Ack frame, a Block Ack frame, or an M-BA frame carried in the HE-TB PPDU based on the format of the received A-MPDU.

[0138] First, Figure 12 (a) illustrates an embodiment in which the STA responds to the A-MPDU using the Ack frame carried in the HE-TB PPDU. According to an embodiment of the present invention, if the MPDU successfully received in the A-MPDU is the only MPDU that requests an immediate response for the Ack context (i.e., the received A-MPDU is recognized as an S-MPDU) and includes the UMRS control field, the STA responds with an Ack frame. In addition, if the MPDU successfully received in the A-MPDU includes only one MPDU that requests an immediate response for the Ack context, zero or more other MPDUs that do not request an immediate response, and a trigger frame, the STA responds with an Ack frame. That is, if the MPDU successfully received in the A-MPDU includes only one MPDU that requests an immediate response and includes the UMRS control field or the trigger frame, the STA responds with an Ack frame.

[0139] In this case, the MPDU requesting an immediate response for the Ack context may include an action frame, a QoS data frame in which the acknowledgment policy is HTP Ack, a QoS null frame in which the acknowledgment policy is HTP Ack, and so on. According to an embodiment of the present invention, the MPDU requesting an immediate response for the Ack context may follow an MPDU delimiter having a value of the EOF field equal to 1 and a value of the MPDU length field not equal to 0. In addition, the MPDU not requesting an immediate response may include an action no Ack frame, a QoS data frame in which the acknowledgment policy is block Ack or no Ack, a QoS null frame in which the acknowledgment policy is block Ack or no Ack, etc.

[0140] According to another embodiment of the present invention, if the received A-MPDU is recognized as including only one MPDU requesting an immediate response for the Ack context, the STA may respond with an M-BA frame. In this case, the STA may insert only one per AID TID information field in the M-BA frame to perform the response for the Ack context. However, since the length of the M-BA frame is longer than the length of the Ack frame, the STA may respond with an M-BA frame only when it can be transmitted according to the specified rules using a modulation and coding scheme (MCS) within the length indicated by the trigger information included in the received MPDU. In this case, the length indicated by the trigger information may be represented by the length field of the common information field of the trigger frame or the HETB PPDU length field of the UMRS control field of the MPDU.

[0141] Next, Figure 12 (b) illustrates an embodiment in which the STA responds to the A-MPDU using a compressed block Ack (C-BA) frame carried in the HE TB PPDU. According to an embodiment of the present invention, when the received A-MPDU is recognized as a single TID A-MPDU, the STA responds with a compressed block Ack (C-BA) frame. That is, if the MPDUs successfully received in the A-MPDU include multiple MPDUs of only one TID requesting an immediate response for the block Ack context and include a UMRS control field or a trigger frame, the STA responds with a C-BA frame. In addition, if the MPDUs successfully received in the A-MPDU include multiple MPDUs of only one TID requesting an immediate response for the block Ack context and one or more other MPDUs not requesting an immediate response and include a UMRS control field or a trigger frame, the STA responds with a C-BA frame. In other words, if all the MPDUs requesting an immediate response for the block Ack context among the MPDUs of the successfully received A-MPDU belong to the same TID and the A-MPDU includes a UMRS control field or a trigger frame, the STA responds with a C-BA frame.

[0142] In this case, the MPDUs that request an immediate response for the block Ack context may include QoS data frames in which the acknowledgment policy is HTP Ack, QoS null frames in which the acknowledgment policy is HTP Ack, and the like. According to one embodiment, the MPDUs that request an immediate response for the block Ack context may follow an MPDU delimiter having a value of the EOF field equal to 0 and a value of the MPDU length field not equal to 0. In addition, the MPDUs that do not request an immediate response may include action no Ack frames, QoS data frames in which the acknowledgment policy is block Ack or no Ack, QoS null frames in which the acknowledgment policy is block Ack or no Ack, and the like. According to another embodiment of the present invention, if the received A-MPDU is recognized as a single TID A-MPDU, the STA may respond with an M-BA frame.

[0143] Next, Figure 12 (c) illustrates an embodiment in which the STA uses a multi-STA block Ack (M-BA) frame carried in a HE TB PPDU to respond to an A-MPDU.

[0144] According to an embodiment of the present invention, when the received A-MPDU is recognized as a multi-TID A-MPDU, the STA responds with a multi-STA block Ack (M-BA) frame. That is, if the MPDUs successfully received in the A-MPDU include MPDUs of two or more TIDs that request an immediate response and include a UMRS control field or a trigger frame, the STA responds with an M-BA frame. In addition, if the MPDUs successfully received in the A-MPDU include MPDUs of one or more TIDs that request an immediate response and an action frame and include a UMRS control field or a trigger frame, the STA responds with an M-BA frame.

[0145] According to another specific embodiment, if the received A-MPDU includes a UMRS control field or a trigger frame and satisfies at least one of the following conditions, the STA may respond with an M-BA frame: i) The A-MPDU includes MPDUs of two or more TIDs that request an immediate response for the block Ack context. ii) The A-MPDU includes MPDUs of one or more TIDs that request an immediate response for the block Ack context and MPDUs of one or more TIDs that request an immediate response for the Ack context. iii) The A-MPDU includes MPDUs of two or more TIDs that request an immediate response for the Ack context. iv) The A-MPDU includes MPDUs of one or more TIDs that request an immediate response for the block Ack context or the Ack context and an action frame.

[0146] In this case, the MPDU that requests an immediate response for the block Ack context may include a QoS data frame in which the acknowledgment policy is HTP Ack, a QoS null frame in which the acknowledgment policy is HTP Ack, and the like. According to one embodiment, the MPDU that requests an immediate response for the block Ack context may follow an MPDU delimiter having a value of the EOF field equal to 0 and a value of the MPDU length field not equal to 0. In addition, the MPDU that requests an immediate response for the Ack context may include an action frame, a QoS data frame in which the acknowledgment policy is HTP Ack, a QoS null frame in which the acknowledgment policy is HTP Ack, and the like. According to an embodiment of the present invention, the MPDU that requests an immediate response for the Ack context may follow an MPDU delimiter having a value of the EOF field equal to 1 and a value of the MPDU length field not equal to 0.

[0147] When sending a response using an M-BA frame, the response may be performed through the per-AID TID information field that is independent for each TID. A specific embodiment thereof is described as in Figure 11 the embodiment of (c).

[0148] Figure 13 FIG. illustrates an embodiment of a method for an AP to send a response frame for an A-MPDU. In a non-traditional wireless LAN system, the AP may receive a PPDU sent by one or more STAs through uplink multi-user (UL MU) transmission. Therefore, the format of the response frame and the format of the PPDU carrying the response frame may be determined according to the A-MPDU configuration of the PPDU received by the AP from one or more STAs.

[0149] First, Figure 13 (a) FIG. illustrates an embodiment in which the AP receives an A-MPDU sent by one or more STAs and responds using a response frame carried in an HE MU PPDU. The AP receives an A-MPDU sent by one or more STAs and constructs a response frame for each STA according to the above embodiment. When multiple A-MPDU requests of the received A-MPDU require an immediate response, the AP may perform the response in the HE MU PPDU format. The AP may generate a response frame of an Ack frame, a block Ack frame, or an M-BA frame for each received A-MPDU, and send the generated multiple response frames in the HE MU PPDU format. A specific embodiment for determining the format of the response frame for each received A-MPDU is described above in Figure 11 The AP may send the response frame through the resource unit assigned to each STA. According to an embodiment of the present invention, each response frame carried in the HE MU PPDU may be sent through the resource unit on which the A-MPDU of each STA is sent.

[0150] Next,Figure 13 (b) Illustrates an embodiment in which the AP receives an A-MPDU sent by one or more STAs and responds with a response frame carried in the HE SU PPDU. When the AP receives a HE SU PPDU sent by one STA or only one A-MPDU among the A-MPDUs sent by multiple STAs that requests an immediate response, the AP can perform the response in the HE SU PPDU format. The AP can generate a response frame of an Ack frame, a block Ack frame, or an M-BA frame for the A-MPDU that requires an immediate response, and send the generated response frame in the HE SU PPDU format. Specific embodiments for determining the format of the response frame for the received A-MPDU are as described above in Figure 11 as described.

[0151] According to another embodiment of the present invention, when multiple A-MPDUs of the received A-MPDU request an immediate response, the AP can also perform a response in the HE SU PPDU format. In this case, the response frame carried in the HE SU PPDU can be a group-addressed M-BA frame. The group-addressed M-BA frame can represent response information for each STA and each TID through each AID TID information field.

[0152] Figure 14 Illustrates a method of sending a response frame according to another embodiment of the present invention. According to Figure 14 the embodiment, the response can be performed using the M-BA frames of all formats of A-MPDUs and S-MPDUs carried in the HE PPDU that request an immediate response. In other words, the terminal can uniformly use Figure 14 the multi-TID A-MPDU illustrated in (a), Figure 14 the single-TID A-MPDU illustrated in (b), and Figure 14 the M-BA frame of the S-MPDU illustrated in (c) to respond. When the terminal uniformly responds with the M-BA frame, the implementation is simple and the possibility of the transmitter receiving an unexpected format of the response frame can be eliminated. However, if it is clear that the S-MPDU has been sent, the disadvantage is that the response should be performed using the M-BA frame with a larger data volume than the Ack frame.

[0153] Operation Method for Receiving Failure of Some MPDUs in A-MPDU

[0154] Figures 15 to 19 Illustrates a method of operation of the terminal when the transmission of at least some MPDUs in the A-MPDU has failed. In Figures 15 to 19 the embodiment, the same or corresponding parts as those of the embodiments of the foregoing drawings will be omitted.

[0155] As in the above embodiment, the terminal may generate an A-MPDU including one or more MPDUs requesting an immediate response, and may transmit the generated A-MPDU. The receiver of the A-MPDU determines the format of the response frame based on the number of TIDs requesting an immediate response in the successfully received MPDUs, and transmits the response frame in the determined format. That is, the response frame of the A-MPDU may be generated based on the number of TIDs requesting an immediate response in the MPDUs successfully received by the receiver. According to an embodiment, the action frame included in the successfully received MPDU may be regarded as a separate TID. The terminal receives the response frame of the receiver corresponding to the A-MPDU, and determines whether the transmission of the MPDUs included in the A-MPDU is successful based on the received response frame. When receiving a response frame in the expected format of the A-MPDU transmitted by the terminal according to the above embodiment, the terminal may determine whether each MPDU is successfully transmitted based on the response information of each MPDU included in the response frame.

[0156] Meanwhile, depending on the communication state, the receiver may not be able to receive at least some of the MPDUs of the transmitted A-MPDU. If the reception of at least some MPDUs has failed, the receiver may not be able to determine which of the S-MPDU, single-TID A-MPDU, and multi-TID A-MPDU has been received. Specifically, in the uplink / downlink (UL / DL) OFDMA PPDU used in a non-traditional wireless LAN system, a large amount of EOF padding may be included to align the length of the PPDU. This may more frequently result in a situation where the receiver cannot successfully receive at least part of the received data and cannot determine the configuration of the A-MPDU. Therefore, a subsequent operation method of the communication terminal should be defined in the case where the reception of some of the above MPDUs fails.

[0157] According to an embodiment of the present invention, the terminal may determine whether the transmission of the MPDUs included in the A-MPDU is successful by comparing the format of the response frame expected for the A-MPDU to be transmitted with the format of the response frame actually transmitted from the receiver. As in the above embodiment, the format of the response frame expected for the A-MPDU may be determined based on at least one of the plurality of TIDs of the request immediate response or MPDU delimiter information in one or more MPDUs constituting the A-MPDU. Therefore, the terminal may determine the success or failure of the MPDUs included in the A-MPDU by considering at least one of the plurality of TIDs of the request immediate response or MPDU delimiter information in one or more MPDUs constituting the A-MPDU and considering the response frame corresponding to the transmission of the A-MPDU.

[0158] Figure 15 FIG. illustrates a method of transmitting an A-MPDU and a response frame according to an embodiment of the present invention. Figure 15(a) Illustrates an embodiment in which the terminal transmits an S-MPDU and the receiver fails to receive some of the EOF padding portions included in the S-MPDU. In addition, Figure 15 (b) Illustrates an embodiment in which the terminal transmits a multi-TID A-MPDU and the receiver fails to receive the MPDUs of some TIDs (i.e., TID3).

[0159] Referring to Figure 15 (a), the receiver receives the S-MPDU transmitted by the terminal and sends an Ack frame in response thereto. Since the expected response to the S-MPDU is an Ack frame, the terminal can determine that the transmission of the S-MPDU is successful.

[0160] On the other hand, referring to Figure 15 (b), the receiver only successfully receives some of the MPDUs of the multi-TID A-MPDU transmitted by the terminal. More specifically, although the A-MPDU transmitted by the terminal includes MPDUs of two different TIDs (i.e., TID2 and TID3) that request an immediate response of the Ack context, the receiver only successfully receives one of the MPDUs. Here, the MPDU that requests an immediate response of the Ack context may follow an MPDU delimiter having a value of the EOF field equal to 1 and a value of the MPDU length field not equal to 0. That is, the MPDU (and MPDU delimiter) of a specific TID (i.e., TID2) in the multi-TID A-MPDU is successfully received, but the MPDU (and MPDU delimiter) of another TID (i.e., TID3) is not successfully received. In the embodiment of 15(b), since the receiver only successfully receives one MPDU that requests an immediate response of the Ack context in the multi-TID A-MPDU transmitted by the terminal, it can be determined that the S-MPDU has been received. Therefore, the receiver responds to the multi-TID A-MPDU with an Ack frame.

[0161] The terminal receives the Ack frame sent as a response. However, since the Ack frame does not include a block Ack information field or a TID information field indicating the TID of the response information, the terminal cannot determine which MPDU the received Ack frame is for. Therefore, according to an embodiment of the present invention, when a terminal that has transmitted a multi-TID A-MPDU receives an Ack frame as a response, the terminal determines that the transmission of the multi-TID A-MPDU has failed. In other words, when the transmitted A-MPDU is composed of MPDUs of multiple TIDs that request an immediate response and the response frame corresponding to the A-MPDU is an Ack frame, it is determined that the transmission of the MPDUs included in the A-MPDU has failed. Therefore, the terminal can retransmit the MPDUs included in the A-MPDU for which it has been determined that the transmission has failed.

[0162] However, according to an embodiment of the present invention, in addition to determining that the transmission of the MPDU included in the A-MPDU has failed, since an Ack frame is received in response to the A-MPDU, the terminal may determine that the channel access for transmitting the A-MPDU is successful. Accordingly, the terminal may reset at least one of the EDCA parameters of the access category for the channel access for A-MPDU transmission. In this case, the EDCA parameters may include a contention window, a QoS short retry counter (QSRC), a QoS long retry counter (QLRC), and the like.

[0163] Figure 16 FIG. illustrates a method of transmitting an A-MPDU and a response frame according to another embodiment of the present invention. More specifically, Figure 16 (a) illustrates a method of transmitting a response frame for an A-MPDU according to the above embodiment. Figure 16 (b) illustrates a method of transmitting a response frame for an A-MPDU according to another embodiment of the present invention.

[0164] According to Figure 16 the embodiment of (a), if the receiver has successfully received only one MPDU that requests an immediate response among the multi-TID A-MPDUs transmitted by the terminal, the receiver responds with an Ack frame. However, since the Ack frame does not include a block Ack information field or a TID information field indicating the TID of the response information, the terminal cannot determine for which MPDU the received Ack frame is used.

[0165] Therefore, according to Figure 16 the embodiment of (b), the receiver may determine the format of the response frame based on the reception status of each MPDU of the A-MPDU. As described above, each MPDU follows an MPDU delimiter in the A-MPDU, and the MPDU delimiter indicates the length information of the MPDU. Since each MPDU delimiter indicates the length information of the MPDU, the receiver may determine whether each MPDU and the MPDU delimiter included in the A-MPDU have been successfully received. If the receiver has successfully received only one MPDU that requests an immediate response and has not successfully received at least some MPDUs, there is a possibility that there is another data that requests an immediate response in the MPDUs that have not been successfully received.

[0166] According to an embodiment of the present invention, if there is a possibility that an unsuccessfully received MPDU is an MPDU requesting an immediate response, the receiver can respond with an M-BA frame. For example, if at least one MPDU or MPDU delimiter in an A-MPDU is not successfully received, the receiver can respond with an M-BA frame. More specifically, if at least one MPDU or MPDU delimiter is not successfully received before the first received EOF padding in the A-MPDU, the unsuccessfully received MPDU can be an MPDU requesting an immediate response. Therefore, the receiver can respond with an M-BA frame. That is, even if only one MPDU requesting an immediate response of the Ack context is successfully received, if at least one MPDU or MPDU delimiter is not successfully received before the first received EOF padding in the A-MPDU, the receiver responds with an M-BA frame instead of an Ack frame. In this case, in each AID TID information field of the M-BA frame, the value of the TID subfield can be set to the TID of the successfully received MPDU, and the value of the Ack type subfield can be set to 1, so that the BA bitmap is omitted. That is, if an A-MPDU assumed to be an S-MPDU is received and recognized as an incomplete A-MPDU, the receiver can respond with an M-BA frame instead of an Ack frame.

[0167] On the other hand, if there is a portion that is not successfully received only after the first received EOF padding in the A-MPDU, the unsuccessfully received portion can be another EOF padding. Therefore, the receiver's response may not be forced into an M-BA frame. Additionally, because the above problem only occurs when an error occurs in the received A-MPDU and the receiver responds with an Ack frame, in the case where the receiver should respond with a C-BA frame, the response may not be forced into an M-BA frame.

[0168] According to an embodiment of the present invention, the receiver can respond with an M-BA frame only when the receiver is able to send an M-BA frame within the duration indicated by the successfully received MPDU or the length indicated by the trigger frame received in the A-MPDU. In this case, the receiver can respond with an M-BA frame only when it is able to send an M-BA frame within the duration or length using the MCS according to the specified rules.

[0169] According to another embodiment of the present invention, if an A-MPDU assumed to be an S-MPDU is received and at least a part of the A-MPDU is not successfully received, the receiver can regard the A-MPDU as a multi-TID A-MPDU. Since the response to the multi-TID A-MPDU is performed via an M-BA frame, the receiver can respond to the A-MPDU with an M-BA frame.

[0170] According to another embodiment of the present invention, the use of M-BA frames as responses to HE PPDUs can be extended. In a non-traditional wireless LAN system, M-BA frames can respond to the most configurations of A-MPDUs and can change their form so that an effective response can be performed. Therefore, according to another embodiment of the present invention, in addition to the case of sending an Ack frame as a response, M-BA frames can be generally used as response frames. For example, if at least some MPDUs of an A-MPDU are not successfully received and one or more successfully received MPDUs request an immediate response, a non-traditional wireless LAN terminal can respond with an M-BA frame. Alternatively, if at least some MPDUs of an A-MPDU are not successfully received and one or more successfully received MPDUs request an immediate response, a non-traditional wireless LAN terminal can treat the A-MPDU as a multi-TID A-MPDU. Therefore, the non-traditional wireless LAN terminal responds with an M-BA frame according to the response process for multi-TID A-MPDUs.

[0171] Figure 17 FIG. illustrates a method of transmitting an A-MPDU and a response frame according to another embodiment of the present invention. According to Figure 17 the embodiment, a response frame transmission method that does not change the operation of a traditional receiving terminal can be used to facilitate reducing implementation complexity.

[0172] More specifically, when a terminal that has transmitted an A-MPDU composed of MPDUs of multiple TIDs that request an immediate response receives a response of an Ack frame, the terminal can ignore the response of the Ack frame. Therefore, the terminal should retransmit all MPDUs that make up the A-MPDU. However, since the terminal has received a response frame for the transmitted A-MPDU, it can be determined that the transmission of the A-MPDU has not failed. According to an embodiment of the present invention, the terminal can consider the Enhanced Distributed Channel Access Function (EDCAF) of the access category used for channel access in the previous A-MPDU transmission as not failed. Therefore, the terminal can resume the backoff operation while maintaining EDCA parameters such as the contention window of the access category, the QoS Short Retry Counter (QSRC), and the QoS Long Retry Counter (QLRC) as previous values. According to another embodiment of the present invention, since a response of an Ack frame to the A-MPDU has been received, the terminal can determine that the channel access (i.e., EDCAF) for A-MPDU transmission is successful. Therefore, the terminal can reset at least one EDCA parameter of the access category for channel access for A-MPDU transmission.

[0173] Additional Embodiments of Method for Sending S-MPDU and Response Frame

[0174] Figure 18 and19 FIG. illustrates a method of transmitting S-MPDU and response frames in a non-traditional wireless LAN system according to another embodiment of the present invention.

[0175] Figure 18 FIG. illustrates a method of transmitting S-MPDU and response frames in a non-traditional wireless LAN system according to an embodiment of the present invention. As described above, the configuration of multi-TID A-MPDU is not allowed in a traditional wireless LAN system. In addition, since there can be only one A-MPDU subframe with the value of the EOF field set to 1 for each TID in the A-MPDU, it is obvious that the A-MPDU subframe with the value of the EOF field set to 1 is the only A-MPDU subframe within the A-MPDU. Therefore, among other possibilities, the receiver can respond with an Ack frame.

[0176] However, the configuration of multi-TID A-MPDU is allowed in a non-traditional wireless LAN system. Therefore, in addition to the MPDU requesting an immediate response of the Ack context, the MPDU of another TID requesting an immediate response of the Ack context, multiple MPDUs with the value of the EOF field set to 0, action frames, QoS data / null frames, action no-Ack frames, etc. are allowed to be aggregated and transmitted.

[0177] In a traditional wireless LAN system, if the received A-MPDU contains only one MPDU and the MPDU requests an immediate response of the Ack context, the A-MPDU can be classified as an S-MPDU. Therefore, the receiver can respond with an Ack frame. However, in a non-traditional wireless LAN system, even if the received A-MPDU contains only one MPDU requesting an immediate response, when it is aggregated with one or more other MPDUs that do not request an immediate response, it can be classified as an A-MPDU rather than an S-MPDU. In this case, the MPDUs that do not request an immediate response can include action no-Ack frames, QoS data frames with the acknowledgment policy being block Ack or no Ack, QoS null frames with the acknowledgment policy being block Ack or no Ack, control responses (e.g., Ack, block Ack), etc. Therefore, in the above case, the receiver cannot respond with an Ack frame. Additionally, since the receiver should respond with a C-BA frame when the A-MPDU is regarded as a single-TID A-MPDU, it is not possible to omit the BA bitmap by setting the Ack type subfield, which may be inefficient.

[0178] Therefore, according to Figure 18In the embodiment of the present invention illustrated in (a), when the received A-MPDU contains only one MPDU requesting an immediate response for the Ack context, even if one or more other MPDUs not requesting an immediate response are aggregated together, the receiving party can regard the A-MPDU as an S-MPDU. Therefore, the receiving party responds with an Ack frame.

[0179] According to Figure 18 In another embodiment of the present invention illustrated in (b), when the received A-MPDU contains only one MPDU requesting an immediate response for the Ack context and one or more other MPDUs not requesting an immediate response, the STA can regard the A-MPDU as a multi-TID A-MPDU. Therefore, the receiving party responds with an M-BA frame. However, the value of the Ack type subfield of each AID TID information field corresponding to the MPDU requesting an immediate response can be set to 1, so that the BA bitmap is omitted.

[0180] Figure 19 A method of transmitting an S-MPDU and a response frame in a non-conventional wireless LAN system according to another embodiment of the present invention is illustrated. If an A-MPDU is carried in a downlink HE MU PPDU, in order for the receiving party to respond, trigger information should be sent together except for the MPDUs whose acknowledgment strategy is a generic Ack. In this case, the trigger information can be sent through the trigger frame included in the MAC header or the UMRS control field. However, a terminal that cannot receive the UMRS control field can respond only when receiving an MPDU requesting an immediate response for the Ack context and a trigger frame.

[0181] Therefore, according to the embodiment of the present invention, when the received A-MPDU contains only one MPDU requesting an immediate response for the Ack context, even if trigger frames are aggregated together, the receiving party can regard the A-MPDU as an S-MPDU. Therefore, the receiving party responds with an Ack frame.

[0182] More specifically, referring to Figure 19 (a), when the received A-MPDU contains only one MPDU requesting an immediate response for the Ack context and a trigger frame, the STA can regard the A-MPDU as an S-MPDU. In addition, referring to Figure 19 (b), even if the received A-MPDU contains only one MPDU requesting an immediate response for the Ack context, one or more MPDUs not requesting an immediate response, and a trigger frame, the STA can also regard the A-MPDU as an S-MPDU. Therefore, the receiving party responds to the received A-MPDU with an Ack frame.

[0183] According to Figure 19 Another embodiment of the present invention illustrated in (c), inFigure 19 In the case illustrated in (a) or 19(b), the recipient may treat the A-MPDU as a multi-STA A-MPDU. Accordingly, the recipient responds with an M-BA frame. However, the value of the Ack type subfield for each AID TID information field corresponding to the MPDU requesting an immediate response may be set to 1 such that the BA bitmap is omitted.

[0184] TID Aggregation Limit

[0185] The AP may use trigger information to indicate the maximum number of TIDs that can be aggregated in an A-MPDU to be sent by each wireless communication terminal. In this case, the trigger information may be sent through at least one of a trigger frame included in the MAC header and a UMRS control field. See Figures 20 to 24 for a description of the operation of the AP indicating the maximum number of TIDs that can be aggregated in an A-MPDU to be sent by each wireless communication terminal by using a trigger frame.

[0186] Figure 20 Illustrated is the operation of a wireless communication terminal based on the maximum number of TID information to send an A-MPDU according to an embodiment of the present invention.

[0187] The AP may use a trigger frame to indicate information about the type of MPDUs included in an A-MPDU to be sent from a wireless communication terminal to the AP. As described above, the AP may use a trigger frame to indicate the maximum number of TIDs that an A-MPDU sent from a wireless communication terminal to the AP can have. Specifically, the AP may use the user information field of the trigger frame to indicate the maximum TID to be sent by the wireless communication terminal corresponding to the user information field. In a specific embodiment, the AP may use the TID aggregation limit of the user information field of the trigger frame to indicate the maximum TID to be sent by the wireless communication terminal corresponding to the user information field. At this time, the wireless communication terminal that receives the trigger frame may set the number of TIDs that the A-MPDU can have based on the trigger frame. Specifically, the wireless communication terminal that receives the trigger frame may set the number of TIDs of the MPDUs included in the A-MPDU to be sent based on the maximum number of TIDs indicated by the trigger frame, and send the A-MPDU to the AP. For example, the wireless communication terminal that receives the trigger frame may set the number of TIDs of the MPDUs included in the A-MPDU to be sent such that it does not exceed the maximum number of TIDs indicated by the trigger frame, and send the A-MPDU to the AP. Thereby, the AP can effectively manage the scoreboard. In addition, the BA bitmap length of each of multiple wireless communication terminals can be adjusted.

[0188] In a specific embodiment, the value of the TID aggregation limit field may indicate the maximum number of TIDs that an A-MPDU sent by a wireless communication terminal receiving a trigger frame to an AP can have. For example, when the TID aggregation limit field is a 3-bit field and has values from 0 to 7, each of the values 0 to 7 may indicate that the maximum number of TIDs of the A-MPDU to be sent to the AP corresponds to any one of 1 to 8.

[0189] In another specific embodiment, the AP may use a trigger frame to indicate that a wireless communication terminal indicated in the trigger frame is not allowed to generate an A-MPDU to be sent to the AP by aggregating MPDUs having TIDs. Specifically, the AP may set the TID aggregation limit to 0 to indicate that the wireless communication terminal indicated in the trigger frame is not allowed to generate an A-MPDU to be sent to the AP by aggregating MPDUs having that TID. However, when the A-MPDU includes an MPDU that requests an immediate response even when the MPDU does not have a TID, the size of the BA frame sent by the receiver in response to the A-MPDU may be increased. In addition, the burden of managing the receiver's scoreboard is increased. At this time, the immediate response may indicate that the receiver sends a response to the initiator within a predetermined time period in the same transmission opportunity (TXOP). Specifically, the predetermined time period may be a short inter-frame space (SIFS).

[0190] In another specific embodiment, the AP may use a trigger frame to indicate that a wireless communication terminal indicated by the trigger frame is not allowed to generate an A-MPDU to be sent to the AP by aggregating MPDUs that immediately respond to the aggregation request. At this time, the MPDU that immediately responds to the request may include an MPDU with quality of service (QoS) data having a TID. Additionally, the MPDU that immediately responds to the request may include a management MPDU (MMPDU) that immediately responds to the request. Specifically, the MPDU that immediately responds to the request may include an action frame. The AP sets the value of the TID aggregation limit field in the user information field of the trigger frame to 0 to indicate that the wireless communication terminal corresponding to the user information field is not allowed to generate an A-MPDU to be sent to the AP by aggregating MPDUs that immediately respond to the aggregation request. When the value of the TID aggregation limit field indicates a value other than 0, it may indicate the maximum number of TIDs that the A-MPDU to be sent to the AP by the wireless communication terminal indicated by the trigger frame may have. Furthermore, when the trigger frame indicates that the wireless communication terminal is not allowed to generate an A-MPDU to be sent to the AP by aggregating MPDUs that immediately respond to the aggregation request, the wireless communication terminal may generate an A-MPDU to be sent to the AP by aggregating MPDUs that do not immediately respond to the request. Specifically, when the value of the TID aggregation limit field in the user information field of the wireless communication terminal corresponding to the trigger frame is 0, the wireless communication terminal may generate an A-MPDU to be sent to the AP by aggregating MPDUs that do not immediately respond to the request. In a specific embodiment, the MPDUs that do not immediately respond to the request may include MPDUs that include QoS data with an ACK policy set to no ACK. When the ACK policy is set to no Ack, the ACK policy may indicate that no ACK is requested for the corresponding frame. Additionally, the MPDUs that do not immediately respond to the request may include QoS null frames. At this time, the QoS null frame may be a QoS null frame with an ACK policy set to no Ack. Additionally, the MPDUs that do not immediately respond to the request may include an action No Ack frame.

[0191] In another specific embodiment, the AP may use a trigger frame to indicate that a wireless communication terminal indicated by the trigger frame is allowed to aggregate MPDUs (without TID quantity restrictions) to generate an A-MPDU and send the generated A-MPDU to the AP. Specifically, the AP sets the value of the TID aggregation limit field in the user information field of the trigger frame to 7 to indicate that the wireless communication terminal corresponding to the user information field is allowed to aggregate MPDUs (without TID quantity restrictions) to generate an A-MPDU and send the generated A-MPDU to the AP.

[0192] In Figure 20In the embodiment, the AP sets the value of the TID aggregation limit field of the user information field of the third station corresponding to the trigger frame to 3, indicating that the maximum number of TIDs of the A-MPDU to be sent from the third station STA3 to the AP is 3. The third station STA3 determines the number of TIDs of the A-MPDU to be sent to the AP based on the value of the TID aggregation limit field of the user information field of the third station corresponding to the trigger frame. Specifically, the third station STA3 determines the number of TIDs of the A-MPDU to be sent to the AP as 3 based on the value of the TID aggregation limit field of the user information field of the third station corresponding to the trigger frame. The third station STA1 aggregates MPDUs with TID 1, MPDUs with TID 2, MPDUs with TID 3, action frames, and QoS null frames to generate an A-MPDU to be sent to the AP. The third station STA3 sends the generated A-MPDU to the AP. The AP sends an M-BA frame to a plurality of wireless communication terminals including the third station STA3 based on the A-MPDU received from the third station SAT3. Through this embodiment, the AP adjusts the duration of the M-BA frame. In Figure 20 In the embodiment, the third station STA3 regards MPDUs without TIDs, such as QoS null frames and action frames, as not included in the number of TIDs indicated by the maximum number of TIDs. However, when there is no block acknowledgment agreement for a specific TID, the response to the MPDU with the corresponding TID may not affect the M-BA frame. In addition, as described above, even MPDUs not corresponding to a specific TID can request an immediate response. Therefore, a specific embodiment is needed to compare the number of TIDs and the maximum number of TIDs of the A-MPDU to be sent from the wireless communication terminal to the AP. This will be described in detail with reference to Figures 21 to 24 as follows.

[0193] Figure 21 FIG. illustrates the operation of a wireless communication terminal transmitting an A-MPDU based on the maximum number of TID information according to another embodiment of the present invention.

[0194] The AP may use a trigger frame to indicate the maximum number of TIDs with a block acknowledgment convention that an A-MPDU to be sent by a wireless communication terminal can have. The wireless communication terminal may calculate the number of TIDs of the A-MPDU based on the number of TIDs with a block acknowledgment convention. In the above embodiment, when the wireless communication terminal compares the number of TIDs of the A-MPDU to be sent to the AP with the maximum number of TIDs, the wireless communication terminal may compare the number of TIDs with a block acknowledgment convention with the maximum number of TIDs. Specifically, when the wireless communication terminal compares the number of TIDs of the A-MPDU to be sent to the AP with the maximum number of TIDs, the wireless communication terminal may not count the TIDs without a block acknowledgment convention as the number of TIDs of the A-MPDU. This is because since the receiver directly sends the data corresponding to the TID without a block acknowledgment convention to the upper layer without storing the data corresponding to the TID in the buffer, the reception of the data corresponding to the TID without a block acknowledgment convention may not affect the management of the scoreboard. In addition, this is because when the wireless communication terminal counts the TIDs without a block acknowledgment convention as the number of TIDs, buffer management and A-MPDU configuration may be restricted. Specifically, when the value of the TID aggregation limit field is from 1 to 6, the wireless communication terminal may generate an A-MPDU having a number of TIDs with a block acknowledgment convention less than or equal to the value of the TID aggregation limit field, and may send the generated A-MPDU to the AP. At this time, regardless of the value of the TID aggregation limit field, the wireless communication terminal may add the MPDU corresponding to the TID without a block acknowledgment convention to the A-MPDU. Further, the AP sets the value of the TID aggregation limit field of the per-user information of the trigger frame to 0 to indicate that the wireless communication terminal corresponding to the per-user information field is allowed to aggregate MPDUs that do not request an immediate response, regardless of the TIDs with a block acknowledgment convention, to generate an A-MPDU and send the generated A-MPDU to the AP. Specifically, when the value of the TID aggregation limit field of the user information field of the wireless communication terminal corresponding to the trigger frame is 0, the wireless communication terminal may generate an A-MPDU to be sent to the AP by aggregating MPDUs that do not request an immediate response.

[0195] In Figure 21In an embodiment, the AP sets the value of the TID aggregation limit field in the user information field of the third station corresponding to the trigger frame to 3, to indicate that the maximum number of TIDs with block acknowledgment convention for the A-MPDU to be sent from the third station STA3 to the AP is 3. The third station STA3 determines the number of TIDs with block acknowledgment convention for the A-MPDU to be sent to the AP based on the value of the TID aggregation limit field in the user information field of the third station corresponding to the trigger frame. The third station STA3 determines that the A-MPDU to be sent to the AP has three TIDs with block acknowledgment convention based on the value of the TID aggregation limit field in the user information field of the third station corresponding to the trigger frame. There are block acknowledgment conventions for TIDs 1, 2, and 4, and there is no block acknowledgment convention for TID 5. Therefore, the third station STA3 aggregates the MPDUs with TID 1, the MPDUs with TID 2, the MPDUs with TID 3, the MPDUs with TID 5, the non-Ack action frames, and the QoS null frames to generate the A-MPDU to be sent to the AP. The third station STA3 sends the generated A-MPDU to the AP. The AP sends the M-BA frame to a plurality of wireless communication terminals including the third station STA3 based on the A-MPDU received from the third station SAT3. Through this embodiment, the AP adjusts the duration of the M-BA frame.

[0196] Data corresponding to a TID without a block acknowledgment convention can also request ACK frame transmission. At this time, the receiver can send an M-BA frame including a Per AID TID field without a block acknowledgment bitmap in response to the MPDU corresponding to the TID without a block acknowledgment convention. Therefore, even if the MPDU corresponding to the TID without a block acknowledgment convention affects the duration of the M-BA frame. Therefore, the maximum number of TIDs that the A-MPDU can have can be calculated based on the number of TIDs that request an immediate response and the number of frames of TIDs that do not request an immediate response. This will be described in more detail with reference to Figure 10 More specifically.

[0197] Figure 22 Illustrates the operation of a wireless communication terminal sending an A-MPDU based on the maximum number of TID information according to another embodiment of the present invention.

[0198] The AP can use a trigger frame to limit the number of MPDUs that request immediate response and can be included in an A-MPDU to be sent by a wireless communication terminal. The AP can use a trigger frame to limit the number of MPDUs that request immediate response and can be had by an A-MPDU to be sent by a wireless communication terminal. The wireless communication terminal can calculate the number of TIDs of the A-MPDU based on the number of TIDs that request immediate response. In the above embodiment, when the wireless communication terminal compares the number of TIDs of the A-MPDU to be sent to the AP with the maximum number of TIDs, the wireless communication terminal can compare the number of TIDs that request immediate response of the A-MPDU with the maximum number of TIDs. When the wireless communication terminal compares the number of TIDs of the A-MPDU to be sent to the AP with the maximum number of TIDs, the number of TIDs of the A-MPDU can be calculated without considering MPDUs that do not request immediate response. Therefore, regardless of the maximum number of TIDs, the wireless communication terminal can aggregate MPDUs corresponding to TIDs that do not request immediate response. In addition, regardless of the maximum number of TIDs, the wireless communication terminal can aggregate frames that do not have TIDs that do not request immediate response. In addition, the number of TIDs that request immediate response can be the sum of the number of frames that request immediate response and are not included in the A-MPDU and the number of TIDs that request immediate response and are included in the A-MPDU. The number of frames without a TID can indicate the type of frames without a TID. In addition, an action frame with a TID of 15 in each AID TID field of the M-BA frame can be one of the frames without a TID that requests immediate response. The MPDU corresponding to a TID that does not request immediate response can be an MPDU corresponding to a TID whose ACK policy is set to no Ack. In addition, the MPDU corresponding to a TID that does not request immediate response can be a QoS null frame. At this time, the ACK policy of the QoS null frame can be no Ack. In addition, a frame without a TID that does not request immediate response can be a no Ack action frame.

[0199] As described above, the AP sets the value of the TID aggregation limit field of the per-user information of the trigger frame to 0 to indicate that the wireless communication terminal corresponding to the per-user information field is allowed to aggregate MPDUs that do not request immediate response, regardless of the TIDs with a block acknowledgment convention, to generate an A-MPDU, and sends the generated A-MPDU to the AP. Specifically, when the value of the TID aggregation limit field of the user information field of the wireless communication terminal corresponding to the trigger frame is 0, the wireless communication terminal can generate an A-MPDU to be sent to the AP by aggregating MPDUs that do not request immediate response.

[0200] In Figure 22In the embodiment, the AP sets the value of the TID aggregation limit field in the user information field of the third station corresponding to the trigger frame to 3, indicating that the maximum value of the sum of the number of TIDs that the A-MPDU to be sent by the third station STA3 to the AP can have and the number of frames of TIDs that do not request an immediate response to be included in the A-MPDU is 3. The third station STA3 determines the sum of the number of TIDs that request an immediate response to the A-MPDU to be sent to the AP and the number of frames of TIDs that do not request an immediate response based on the value of the TID aggregation limit field in the user information field of the third station corresponding to the trigger frame. The third station STA3 determines the sum of the number of TIDs that request an immediate response to the A-MPDU to be sent to the AP and the number of frames of TIDs that do not request an immediate response as 3 based on the value of the TID aggregation limit field in the user information field of the third station corresponding to the trigger frame. TID 1 and 2 request an immediate response, and TID 4 and 5 set the ACK policy to no Ack. In addition, the action frame requests an immediate response. Therefore, the third station STA1 aggregates the MPDU with TID 1, the MPDU with TID 2, the MPDU with TID 4, the MPDU with TID 5, the action frame, the no Ack action frame, and the QoS null frame to generate an A-MPDU to be sent to the AP. The third station STA3 sends the generated A-MPDU to the AP. The AP sends an M-BA frame to a plurality of wireless communication terminals including the third station STA3 based on the A-MPDU received from the third station SAT3. Through this embodiment, the AP adjusts the duration of the M-BA frame.

[0201] Figure 23 FIG. illustrates the operation of a wireless communication terminal for sending an A-MPDU based on the maximum number information of TIDs according to another embodiment of the present invention.

[0202] The multi-TID A-MPDU may not include multiple action frames. Therefore, the multi-TID A-MPDU may include only one action frame. In addition, when the A-MPDU further includes an action frame, the length of the M-BA frame increases by two octets. Therefore, the change in the M-BA duration due to adding an action frame to the A-MPDU is negligible. In addition, it can be seen that the action frame is more important than the QoS data frame.

[0203] When the wireless communication terminal compares the number of TIDs of the A-MPDU to be sent to the AP with the maximum number of TIDs, the wireless communication terminal may not count the number of action frames as the number of TIDs of the A-MPDU. Specifically, when the value of the TID aggregation limit field is within a predetermined range, the wireless communication terminal may generate an A-MPDU to be sent to the AP by aggregating action frames regardless of the value of the TID aggregation limit field. Specifically, in Figures 20 to 22In an embodiment, the wireless communication terminal may not calculate the number of action frames as the number of TIDs of the A-MPDU.

[0204] In Figure 23 In an embodiment, the AP sets the value of the TID aggregation limit field of the user information field of the third station corresponding to the trigger frame to 2, indicating that the maximum value of the sum of the number of TIDs that the A-MPDU to be sent from the third station STA3 to the AP can have and the number of frames with TIDs that are included in the A-MPDU excluding action frames and that do not request an immediate response is 3. At this time, action frames are excluded from the maximum value calculation. The third station STA3 determines the number of TIDs that request an immediate response of the A-MPDU to be sent to the AP and the number of frames with TIDs that are included in the A-MPDU excluding action frames and that do not request an immediate response based on the value of the TID aggregation limit field of the user information field of the third station corresponding to the trigger frame. The third station STA3 determines that the A-MPDU to be sent to the AP has two TIDs that request an immediate response based on the value of the TID aggregation limit field of the user information field of the third station corresponding to the trigger frame. TIDs 1 and 2 request an immediate response, while TIDs 4 and 5 have an ACK policy set to no Ack. In addition, action frames are excluded from the count. Therefore, the third station STA1 aggregates MPDUs with TID 1, MPDUs with TID 2, MPDUs with TID 4, MPDUs with TID 5, action frames, no Ack action frames, and QoS null frames to generate an A-MPDU to be sent to the AP. The third station STA3 sends the generated A-MPDU to the AP. The AP sends an M-BA frame to a plurality of wireless communication terminals including the third station STA3 based on the A-MPDU received from the third station SAT3. Through this embodiment, the AP adjusts the duration of the M-BA frame.

[0205] The AP may use trigger information to instruct a wireless communication terminal that sends a response to the trigger information to perform channel sensing before sending the response. Specifically, the AP may set the value of the required CS field of the trigger information to indicate that a wireless communication terminal that sends a response to the trigger information performs channel sensing before sending the response. The required CS field indicates whether channel sensing is required when a wireless communication terminal sends a response to the trigger information. At this time, when the value of the required CS field is 1, the required CS field may indicate a requirement for channel sensing. In addition, when sending a response to the trigger information, the wireless communication terminal that receives the trigger information may determine whether to perform channel sensing based on the required CS field of the trigger information. Specifically, when the value of the required CS field of the trigger information is 1, the wireless communication terminal that receives the trigger information may perform channel sensing when sending a response to the trigger information. At this time, channel sensing may indicate whether the channel for sending a response to the trigger information is idle. In addition, channel sensing may indicate a CCA operation.

[0206] Figure 24 An operation of setting information on the maximum number of TIDs of a trigger frame in a wireless communication terminal according to an embodiment of the present invention is illustrated.

[0207] When an AP uses trigger information to trigger an immediate response to data transmission, the AP can use the trigger information to indicate that channel sensing is not required when the wireless communication terminal sends a response to the trigger information. Specifically, when the AP uses trigger information to trigger an immediate response to data transmission and the value of the length field in the common information field of the trigger information is less than or equal to a predetermined value, the AP can use the trigger information to indicate that channel sensing is not required when the wireless communication terminal sends a response to the trigger information. At this time, the length field indicates information about the length of the trigger-based PPDU. Specifically, the length field can indicate information about the length of the trigger-based PPDU. In addition, the predetermined value can be 418 bytes. By doing so, the AP can prevent the wireless communication terminal that sends a response to the trigger information from not sending an immediate response due to channel sensing. At this time, there is an operation problem that the wireless communication terminal sends a response to the trigger information and data together. This is because when a wireless communication terminal operating as EDCA sends data, the wireless communication terminal may be required to send data after performing channel sensing. In addition, this is because when the wireless communication terminal that sends a response to the trigger information sends an MPDU requesting an immediate response, an additional transmission sequence is required.

[0208] In a case where channel sensing is not required when the wireless communication terminal indicated by the trigger frame sends a response to the trigger information, the terminal can generate an A-MPDU by aggregating MPDUs that do not request an immediate response and send the generated A-MPDU. Specifically, in a case where channel sensing is not required when the wireless communication terminal indicated by the trigger frame sends a response to the trigger information, the AP can set the value of the TID aggregation limit field in the user information field of the trigger frame to 0 to indicate that the wireless communication terminal indicated by the user information field is not allowed to aggregate MPDUs requesting an immediate response to generate an A-MPDU. Specifically, when the AP uses trigger information to trigger an immediate response to data transmission and the value of the length field in the common information field of the trigger information is less than or equal to a predetermined value, it can be indicated that the wireless communication terminal indicated by the trigger frame is not allowed to aggregate MPDUs requesting an immediate response to generate an A-MPDU and send the generated A-MPDU. In these embodiments, the wireless communication terminal can aggregate MPDUs that do not request an immediate response to generate an A-MPDU and send the generated A-MPDU to the AP.

[0209] In Figure 24In an embodiment, the AP sends a HE MU PPDU to multiple stations. At this time, the HE MU PPDU includes a trigger frame requesting an immediate response to the data MPDU included in the HE MU PPDU. In addition, the value of the length field in the common information field of the trigger frame is 418. In addition, the required CS bit of the trigger frame is set to 0. Therefore, the AP sets the value of the TID aggregation limit field in the user information field of the trigger frame to 0. The wireless communication terminals that receive the trigger frame with the received CS requirement bit set to 0 send together a response to the data MPDU included in the HE MU PPDU and an A-MPDU including MPDUs that do not request an immediate response. At this time, the value of the length field of the trigger frame that triggers a trigger-based PPDU (HE TB PPDU) including the A-MPDU is less than or equal to 418. Therefore, the first station sends an A-MPDU including an MPDU that includes a BA frame and data with an ACK policy of no Ack. The second station sends an A-MPDU including a BA frame and a no-Ack action frame. The third and fourth stations send an A-MPDU including a BA frame and a QoS null frame.

[0210] Although the present invention is described by using wireless LAN communication as an example, the present invention is not limited thereto, and the present invention can be similarly applied even to other communication systems, such as cellular communication and the like. In addition, although the methods, apparatuses, and systems of the present invention are described in conjunction with specific embodiments, some or all of the components and operations of the present invention can be implemented by using a computer system having a general hardware structure.

[0211] The embodiments of the detailed description of the present invention can be implemented by various means. For example, the embodiments of the present invention can be implemented by hardware, firmware, software, and / or a combination thereof.

[0212] In the case of hardware implementation, the method according to the embodiments of the present invention can be implemented by one or more of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microcontroller, a microprocessor, and the like.

[0213] In the case of firmware implementation or software implementation, the method according to the embodiments of the present invention can be implemented by modules, procedures, functions, and the like that perform the operations described above. The software code can be stored in a memory and operated by a processor. The processor can be internally or externally equipped with a memory, and the memory can exchange data with the processor through various publicly known devices.

[0214] The description of the present invention is for illustrative purposes, and those skilled in the art will be able to understand that the present invention can be easily modified into other detailed forms without changing the technical idea or its essential features. Therefore, it should be understood that the embodiments described above are illustrative in every sense and not restrictive. For example, each component described as a single type can be implemented distributively, and similarly, components described as distributed can also be implemented in an associated form.

[0215] The scope of the present invention is represented by the claims to be described below rather than the detailed description, and it is to be interpreted that the meaning and scope of the claims and all changes or modifications derived from their equivalents fall within the scope of the present invention.

[0216] Industrial Applicability

[0217] Various exemplary embodiments of the present invention have been described with reference to the IEEE 802.11 system. However, the present invention is not limited thereto, and the present invention can be applied to various types of mobile communication devices, mobile communication systems, and the like.

Claims

1. A wireless communication terminal, the terminal comprising: a processor; and a communication unit, wherein the processor is configured to: receive a physical layer protocol data unit (PPDU) including an aggregated media access control protocol data unit (A-MPDU), wherein the A-MPDU includes one or more subframes associated with one or more MPDUs, and includes one or more traffic identifiers (TIDs) corresponding to the one or more MPDUs, wherein each of the one or more subframes includes i) a corresponding MPDU including Ack policy information in the one or more MPDUs, and ii) MPDU identifier information associated with the corresponding MPDU, and wherein the MPDU identifier information includes a frame end of frame (EOF) field and a length field, and send a response frame in response to the PPDU, wherein the type of the response frame is determined based on i) the type of the MPDU determined based on a combination of the EOF field and the length field, or ii) a combination of the Ack policy information to be one of an Ack frame, a compressed BlockAck frame, or a multi-STA BlockAck frame.

2. The wireless communication terminal according to claim 1, Among them, when i) the PPDU includes two or more MPDUs and ii) the two or more MPDUs include at least one MPDU of at least one TID in which the MPDU is successfully received, the type of the response frame is determined to be a multi-STA BlockAck frame.

3. The wireless communication terminal according to claim 1, Among them, the type of the response frame is determined by further considering the number of TIDs in which the MPDU is successfully received among the one or more TIDs, wherein the MPDU corresponding to each of the TIDs indicates an immediate response.

4. The wireless communication terminal according to claim 3, Among them, when the A-MPDU includes only one TID among the one or more TIDs and the Ack policy information corresponding to the only one TID indicates normal Ack, the type of the response frame is the Ack frame.

5. The wireless communication terminal according to claim 3, Among them, when i) the number of the TIDs is one or more, ii) the one or more TIDs are the same, and iii) the Ack policy information for at least one MPDU corresponding to the one or more TIDs indicates implicit BlockAck, the type of the response frame is the compressed BlockAck frame.

6. The wireless communication terminal according to claim 1, Among them, when the value of the EOF field is 1 and the value of the length field is non-zero, the type of the MPDU is determined to be a first type, and wherein when the value of the EOF field is 0 and the value of the length field is non-zero, the type of the MPDU is determined to be a second type.

7. A wireless communication method of a wireless communication terminal, the method comprising: Receive a physical layer protocol data unit (PPDU) including an aggregated media access control protocol data unit (A-MPDU), wherein the A-MPDU includes one or more subframes associated with one or more MPDUs, and includes one or more traffic identifiers (TIDs) corresponding to the one or more MPDUs, wherein each of the one or more subframes includes i) a corresponding MPDU including Ack policy information of the one or more MPDUs, and ii) MPDU identifier information associated with the corresponding MPDU, and wherein the MPDU identifier information includes an end-of-frame (EOF) field and a length field, and send a response frame in response to the PPDU, wherein the type of the response frame is determined to be one of an Ack frame, a compressed BlockAck frame, or a multi-STA BlockAck frame based on i) the type of the MPDU determined based on a combination of the EOF field and the length field or ii) a combination of the Ack policy information.

8. The wireless communication method according to claim 7, Among them, wherein when i) the PPDU includes two or more MPDUs and ii) the two or more MPDUs include at least one MPDU of at least one TID in which the MPDU is successfully received among one or more TIDs, the type of the response frame is determined to be a multi-STA BlockAck frame.

9. The wireless communication method according to claim 7, Among them, wherein the type of the response frame is determined by further considering the number of TIDs in which the MPDU is successfully received among the one or more TIDs, wherein the MPDU corresponding to each of the TIDs indicates an immediate response.

10. The wireless communication method according to claim 8, Among them, wherein when the A-MPDU includes only one TID among one or more TIDs and the Ack policy information corresponding to the only one TID indicates normal Ack, the type of the response frame is the Ack frame.

11. The wireless communication method according to claim 9, Among them, wherein when i) the number of the TIDs is one or more, ii) the one or more TIDs are the same, and iii) the Ack policy information for at least one MPDU corresponding to the one or more TIDs indicates implicit BlockAck, the type of the response frame is the compressed BlockAck frame.

12. The wireless communication method according to claim 7, Among them, wherein when the value of the EOF field is 1 and the value of the length field is non-zero, the type of the MPDU is determined to be a first type, and wherein when the value of the EOF field is 0 and the value of the length field is non-zero, the type of the MPDU is determined to be a second type.

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