Wireless communication method and wireless communication terminal using a plurality of basic service identifier sets

Abstract

The present disclosure relates to a wireless communication method and a wireless communication terminal using a plurality of basic service identifier sets. Disclosed is a wireless communication terminal that communicates wirelessly, the wireless communication terminal including: a transceiver unit and a processor. The processor is configured to receive a frame through the transceiver unit and access a channel according to whether the frame is a frame within a basic service set (BSS) or an inter-BSS frame. A frame within a BSS represents a frame transmitted from the same BSS as the BSS including the wireless communication terminal, and an inter-BSS frame represents a frame transmitted from a BSS other than the BSS including the wireless communication terminal.

Description

[0001] This application is a divisional application of the patent application with the application number 201680071981.6 (PCT / KR2016 / 014494), the international filing date of December 9, 2016, and the invention title of "Wireless Communication Method and Wireless Communication Terminal Using Multiple Basic Service Identifier Sets", which was filed with the Chinese Patent Office on June 8, 2018. Technical Field

[0002] The present invention relates to a wireless communication method and a wireless communication terminal using multiple basic service identifier sets. Background Art

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

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

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

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

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

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

[0009] TECHNICAL PROBLEM

[0010] An object of an embodiment of the present invention is to provide a wireless communication method and a wireless communication terminal using a multi-basic service identifier set.

[0011] TECHNICAL SOLUTION

[0012] According to an embodiment of the present invention, a wireless communication terminal that communicates wirelessly includes: a transceiver; and a processor, wherein the processor receives a frame through the transceiver and accesses a channel according to whether the frame is a frame within a basic service set (BSS) or an inter-BSS frame, wherein a frame within a BSS indicates a frame transmitted from the same BSS as the BSS including the wireless communication terminal, and an inter-BSS frame indicates a frame transmitted from a BSS other than the BSS including the wireless communication terminal.

[0013] A first BSS that is a BSS of the wireless communication terminal may correspond to a multi-BSS identifier (BSSID) set, wherein the processor may regard a frame transmitted from a second BSS corresponding to the multi-BSSID as a frame within a BSS, wherein the multi-BSSID set may be a set of BSSIDs of each of multiple BSSs classified into one group.

[0014] The multiple BSSs corresponding to the multi-BSSID set may have the same BSS color value, and the BSS color may be information for identifying a BSS signaled through the physical layer of a frame.

[0015] The processor may determine whether the frame is a frame within a BSS or an inter-BSS frame based on a MAC address signaled in the MAC layer of the frame and multiple BSSIDs included in the multi-BSSID set.

[0016] When the MAC address signaled in the MAC layer of the frame matches any one of the multiple BSSIDs included in the multi-BSSID set, the processor may determine the frame as a frame within a BSS.

[0017] When the transmitter address or the receiver address signaled in the MAC layer of the frame corresponds to another BSSID of the multi-BSSID set, the processor may determine the frame as a frame within a BSS.

[0018] When the frame is a frame within a BSS and the recipient of the frame is not the wireless communication terminal, the processor may enter a power-saving state.

[0019] When the MAC address signaled in the MAC layer of a frame matches any one of the multiple BSSIDs included in a multi - BSSID set and the receiver of the frame is not a wireless communication terminal, the processor may enter a power - saving state.

[0020] When the receiver address or the transmitter address of a frame is one of the multiple BSSIDs included in a multi - BSSID set and the receiver address of the frame is not the MAC address of a wireless communication terminal, the processor may enter a power - saving state.

[0021] The processor may maintain the power - saving state during the duration of the PPDU including the frame.

[0022] The processor may separately set the Network Allocation Vector (NAV) for frames within a BSS and the NAV for frames between BSSs.

[0023] When the MAC address signaled in the MAC layer of a frame matches any one of the multiple BSSIDs included in a multi - BSSID set, the processor may set the NAV for frames within a BSS based on the frame.

[0024] According to an embodiment of the present invention, a method of operating a wireless communication terminal that communicates wirelessly includes: receiving a frame; and accessing a channel according to whether the frame is a frame within a Basic Service Set (BSS) or a frame between BSSs, where a frame within a BSS indicates a frame sent from the same BSS as the BSS including the wireless communication terminal, and a frame between BSSs indicates a frame sent from a BSS other than the BSS including the wireless communication terminal.

[0025] A first BSS that is a BSS of the wireless communication terminal may correspond to a multi - Basic Service Set Identifier (BSSID) set, where accessing a channel according to whether the frame is a frame within a Basic Service Set (BSS) or a frame between BSSs may include treating a frame sent from a second BSS corresponding to the multi - BSSID as a frame within a BSS, where the multi - BSSID set may be a set of BSSIDs of each of multiple BSSs classified into one group.

[0026] The multiple BSSs corresponding to the multi - BSSID set may have the same BSS color value, and the BSS color may be information for identifying the BSS signaled through the physical layer of the frame.

[0027] Treating a frame sent from a second BSS corresponding to the multi - BSSID as a frame within a BSS may include determining whether the frame is a frame within a BSS or a frame between BSSs based on the MAC address signaled in the MAC layer of the frame and the multiple BSSIDs included in the multi - BSSID set.

[0028] Determining whether a frame is an in-BSS frame or an inter-BSS frame may include: determining the frame as an in-BSS frame when the MAC address signaled in the MAC layer of the frame matches any one of the multiple BSSIDs included in the multi-BSSID set.

[0029] Determining the frame as an in-BSS frame may include: determining the frame as an in-BSS frame when the transmitter address or the receiver address signaled in the MAC layer of the frame corresponds to another BSSID of the multi-BSSID set.

[0030] The method may further include: entering a power-saving state when the frame is an in-BSS frame and the recipient of the frame is not a wireless communication terminal.

[0031] Entering the power-saving state may include: entering the power-saving state when the MAC address signaled in the MAC layer of the frame matches any one of the multiple BSSIDs included in the multi-BSSID set and the recipient of the frame is not a wireless communication terminal.

[0032] Advantageous Effects

[0033] Embodiments of the present invention provide a wireless communication method and a wireless communication terminal using a multi-basic service identifier set. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Shows a wireless LAN system according to an embodiment of the present invention.

[0035] Figure 2 Shows a wireless LAN system according to another embodiment of the present invention.

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

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

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

[0039] Figure 6 Shows a network for a virtual LAN according to an embodiment of the present invention.

[0040] Figure 7 Shows a signaling format of information regarding a multi-basic service identifier set according to an embodiment of the present invention.

[0041] Figure 8 Shows a spatial reuse operation of a wireless communication terminal when the wireless communication terminal uses a multi-BSSID set according to an embodiment of the present invention.

[0042] Figure 9 Shows a network for a virtual LAN according to an embodiment of the present invention.

[0043] Figure 10 Shows a power saving operation of a wireless communication terminal according to an embodiment of the present invention.

[0044] Figure 11 Shows a channel access operation of a wireless communication terminal according to an embodiment of the present invention.

[0045] Figure 12 Shows a channel access operation of a wireless communication terminal according to another embodiment of the present invention.

[0046] Figure 13 Shows a method for setting BSS color values of multiple BSSs corresponding to a multi - BSSID set according to an embodiment of the present invention.

[0047] Figure 14 Shows a situation where a wireless communication terminal enters a power saving state based on the MAC header of a frame received by the wireless communication terminal according to an embodiment of the present invention.

[0048] Figure 15 Shows a situation where a wireless communication terminal enters a power saving state based on the MAC header of a frame received by the wireless communication terminal when the wireless communication terminal is included in a BSS corresponding to a multi - BSSID set according to an embodiment of the present invention.

[0049] Figure 16 Shows a method for displaying identifiers of wireless communication terminals included in multiple BSSs corresponding to a multi - BSSID set according to an embodiment of the present invention.

[0050] Figure 17 Shows a trigger frame format according to an embodiment of the present invention.

[0051] Figure 18 Shows a trigger frame format according to another embodiment of the present invention.

[0052] Figure 19 Shows a trigger frame format according to another embodiment of the present invention.

[0053] Figure 20 Shows an OFDMA backoff operation of a wireless communication terminal according to an embodiment of the present invention.

[0054] Figure 21 Shows an operation of a wireless communication terminal according to an embodiment of the present invention. Detailed Description

[0055] Preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. However, the present invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted to clearly describe the present invention, and like reference numerals refer to like elements throughout.

[0056] In addition, when it is described that a thing includes (or comprises or has) some elements, it should be understood that, without specific limitation, it may include (or comprise or have) only those elements, or it may include (or comprise or have) other elements as well as those elements.

[0057] This application claims the priority and benefits of Korean Patent Application Nos. 10-2015-0175411 (December 9, 2015), 10-2015-0186868 (December 24, 2015), 10-2016-0004464 (January 13, 2016), and 10-2016-0114821 (September 7, 2016) filed with the Korean Intellectual Property Office, and the embodiments and items mentioned in the corresponding applications are included in the detailed description of this application.

[0058] Figure 1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. For convenience of description, embodiments of the present invention are described by way of a wireless LAN system. The wireless LAN system includes one or more basic service sets (BSSs), and a BSS represents a set of devices that have successfully synchronized with each other to communicate with each other. Generally, BSSs can be classified into infrastructure BSSs and independent BSSs (IBSSs), and Figure 1 illustrates an infrastructure BSS between them.

[0059] As Figure 1 illustrated, the infrastructure BSSs (BSS1 and BSS2) include one or more stations STA1, STA2, STA3, STA4, and STA5, access points PCP / AP-1 and PCP / AP-2 as stations providing distribution services, and a distribution system (DS) connecting the multiple access points PCP / AP-1 and PCP / AP-2.

[0060] A station (STA) is a predetermined device including a Medium Access Control (MAC) that follows the procedures of the IEEE 802.11 standard and a physical layer interface for a wireless medium, and in a broad sense includes a non-Access Point (non-AP) station and an Access Point (AP). Additionally, in this specification, the term "terminal" can be used to refer to the concept including wireless LAN communication devices such as non-AP STAs or APs or both terms. A station for wireless communication includes a processor and a transceiver, and according to this embodiment, may further include a user interface unit and a display unit. The processor can generate frames to be transmitted through a wireless network or process frames received through a wireless network, and in addition, execute various processes for controlling the station. Furthermore, the transceiver is functionally connected to the processor and transmits and receives frames through the wireless network for the station.

[0061] An Access Point (AP) is an entity that provides access to a Distribution System (DS) for stations associated with it via a wireless medium. In an infrastructure BSS, communication between non-AP stations is in principle performed via an AP, but when a direct link is configured, direct communication can also be achieved even between non-AP stations. Meanwhile, in the present invention, an AP is used as the concept including a Personal BSS Coordination Point (PCP) and can include in a broad sense the concept including a centralized controller, a Base Station (BS), a Node B, a Base Transceiver System (BTS), and a Site Controller.

[0062] Multiple infrastructure BSSs can be connected to each other through a Distribution System (DS). In this case, multiple BSSs connected through the distribution system are called an Extended Service Set (ESS).

[0063] Figure 2 FIG. illustrates an Independent BSS as a wireless communication system according to another embodiment of the present invention. For the convenience of description, another embodiment of the present invention is described through a wireless LAN system. In Figure 2 In the embodiment of, the repeated description of parts that are the same as or corresponding to the embodiment of Figure 1 will be omitted.

[0064] Since Figure 2 the BSS3 illustrated in is an independent BSS and does not include an AP, all stations STA6 and STA7 are not connected to an AP. The independent BSS is not permitted to access the distribution system and forms a complete network. In the independent BSS, the corresponding stations STA6 and STA7 can be directly connected to each other.

[0065] Figure 3 is a block diagram illustrating the configuration of a station 100 according to an embodiment of the present invention.

[0066] As Figure 3As illustrated, the station 100 according to an embodiment of the present invention may include a processor 110, a transceiver 120, a user interface unit 140, a display unit 150, and a memory 160.

[0067] First, the transceiver 120 transmits and receives wireless signals such as wireless LAN physical layer frames and may be embedded in the station 100 or provided externally. According to this embodiment, the transceiver 120 may include at least one transmit and receive module using different frequency bands. For example, the transceiver 120 may include transmit and receive modules having different frequency bands such as 2.4 GHz, 5 GHz, and 60 GHz. According to an embodiment, the station 100 may include a transmit and receive module using a frequency band of 6 GHz or higher and a transmit and receive module using a frequency band of 6 GHz or lower. The corresponding transmit and receive modules may perform wireless communication with an AP or an external station according to the wireless LAN standard of the frequency band supported by the corresponding transmit and receive module. The transceiver 120 may operate only one transmit and receive module at a time or operate multiple transmit and receive modules simultaneously according to the performance and requirements of the station 100. When the station 100 includes multiple transmit and receive modules, each transmit and receive module may be implemented by an independent element or multiple modules may be integrated into one chip.

[0068] Next, the user interface unit 140 includes various types of input / output devices provided in the station 100. That is, the user interface unit 140 may receive user input by using various input devices and the processor 110 may control the station 100 based on the received user input. In addition, the user interface unit 140 may perform output based on a command from the processor 110 by using various output devices.

[0069] Next, the display unit 150 outputs an image on a display screen. The display unit 150 may output various display objects such as content executed by the processor 110 or a user interface based on a control command of the processor 110 and the like. In addition, the memory 160 stores control programs used in the station 100 and various resultant data. The control program may include an access program required for the station 100 to access an AP or an external station.

[0070] The processor 110 of the present invention can execute various commands or programs and process data in the station 100. Additionally, the processor 110 can control corresponding units of the station 100 and control data transmission / reception between these units. According to an embodiment of the present invention, the processor 110 can execute a program for accessing an AP stored in the memory 160 and receive a communication configuration message sent by the AP. Additionally, the processor 110 can read information about the priority conditions of the station 100 included in the communication configuration message and request access to the AP based on the information about the priority conditions of the station 100. The processor 110 of the present invention can represent the main control unit of the station 100 and, according to this embodiment, the processor 110 can represent a control unit for individually controlling a certain component (e.g., the transceiver 120, etc.) of the station 100. The processor 110 can be a modulator and / or demodulator that modulates wireless signals sent to the transceiver 120 and demodulates wireless signals received from the transceiver 120. The processor 110 controls various operations of wireless signal transmission / reception of the station 100 according to an embodiment of the present invention. Detailed embodiments thereof will be described below.

[0071] Figure 3 The station 100 illustrated in is a block diagram according to an embodiment of the present invention, where individual blocks are illustrated as logically distinct elements of the device. Therefore, the elements of the device can be installed in a single chip or multiple chips depending on the design of the device. For example, the processor 110 and the transceiver 120 can be integrated into a single chip or implemented as separate chips. Additionally, in an embodiment of the present invention, some components of the station 100, such as the user interface unit 140 and the display unit 150, can be optionally provided in the station 100.

[0072] Figure 4 is a block diagram illustrating the configuration of an AP 200 according to an embodiment of the present invention.

[0073] As Figure 4 illustrated, the AP 200 according to an embodiment of the present invention can include a processor 210, a transceiver 220, and a memory 260. In Figure 4 Among the components of the AP 200, a repetitive description of parts that are the same as or corresponding to the components of the Figure 2 station 100 will be omitted.

[0074] Referring to Figure 4 , the AP 200 according to the present invention includes a transceiver 220 for operating a BSS in at least one frequency band. As Figure 3As described in the embodiments, the transceiver 220 of the AP 200 may also include multiple transmission and reception modules using different frequency bands. That is, the AP 200 according to an embodiment of the present invention may include two or more transmission and reception modules among different frequency bands (e.g., 2.4 GHz, 5 GHz, and 60 GHz) together. Preferably, the AP 200 may include a transmission and reception module using a frequency band of 6 GHz or higher and a transmission and reception module using a frequency band of 6 GHz or lower. The corresponding transmission and reception modules may perform wireless communication with a station according to the wireless LAN standard of the frequency band supported by the corresponding transmission and reception module. The transceiver 220 may operate only one transmission and reception module at a time or operate multiple transmission and reception modules simultaneously according to the performance and requirements of the AP 200.

[0075] Next, the memory 260 stores control programs used in the AP 200 and various result-obtained data. The control program may include an access program for managing access of stations. In addition, the processor 210 may control the corresponding units of the AP 200 and control data transmission / reception between these units. According to an embodiment of the present invention, the processor 210 may execute a program for accessing a station stored in the memory 260 and send a communication configuration message for one or more stations. In this case, the communication configuration message may include information about the access priority conditions of the corresponding station. In addition, the processor 210 performs access configuration according to the access request of the station. The processor 210 may be a modulator and / or demodulator that modulates a wireless signal sent to the transceiver 220 and demodulates a wireless signal received from the transceiver 220. The processor 210 controls various operations such as radio signal transmission / reception of the AP 200 according to the first embodiment of the present invention. Its detailed embodiments will be described below.

[0076] Figure 5 is a diagram schematically illustrating the process of a STA setting a link with an AP.

[0077] Reference Figure 5 , the link between the STA 100 and the AP 200 is generally set through three steps of scanning, authentication, and association. First, the scanning step is a step in which the STA 100 obtains access information of the BSS operated by the AP 200. The methods for performing scanning include a passive scanning method in which the AP 200 obtains information by using beacon messages (S101) sent periodically and an active scanning method in which the STA 100 sends a probe request (S103) to the AP and obtains access information by receiving a probe response (S105) from the AP.

[0078] The STA 100 that has successfully received the wireless access information in the scanning step performs an authentication step by sending an authentication request (S107a) and receiving an authentication response from the AP 200 (S107b). After the authentication step is performed, the STA 100 performs an association step by sending an association request (S109a) and receiving an association response from the AP 200 (S109b).

[0079] 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, the authentication server 300 is a server that processes 802.1X-based authentication for the STA 100 and can exist physically associated with the AP 200 or as a separate server.

[0080] In a specific embodiment, the AP 200 can be a wireless communication terminal that allocates communication medium resources and performs scheduling in an independent network not connected to an external distribution service (such as an ad hoc network). In addition, the AP 200 can be at least one of a base station, an eNB, and a transmission point TP.

[0081] Figure 6 A network for a virtual LAN according to an embodiment of the present invention is shown.

[0082] A plurality of virtual LANs (VLANs) can constitute a network. In Figure 6 this embodiment, an Ethernet switch (802.3 bridge) connects an airport VLAN, a lounge VLAN, and a management VLAN. In a network composed of multiple VLANs, the Ethernet switch (802.3 bridge) can control QoS through virtual LANs. Specifically, the Ethernet switch (802.3 bridge) can control the traffic speed according to the virtual LAN. Specifically, the Ethernet switch (802.3 bridge) can control the traffic speed according to the virtual LAN. Specifically, the Ethernet switch (802.3 bridge) can assign different access rights to each virtual LAN.

[0083] At this time, the network can include multiple physical access points. However, when there are multiple physical access points in a network, due to the management frames sent by the multiple access points, the time for frames used for data transmission to occupy the channel can be very short. Therefore, in the network, as Figure 6 shown in, a wireless communication terminal can operate multiple BSSs. A method for a wireless communication terminal to operate multiple BSSs will be described in detail with reference to Figure 7 this. In addition, unless otherwise specified, frames in this specification refer to MAC frames.

[0084] Figure 7A signaling format showing information about a multi-basic service identifier set according to an embodiment of the present invention.

[0085] A wireless communication terminal may signal information about multiple BSSs through one management frame. Specifically, the wireless communication terminal may signal information about a multi-BSSID set including multiple BSS identifiers (BSSIDs) through the management frame. The multi-BSSID set is a set of BSSIDs of multiple BSSs classified into one group. When the wireless communication terminal uses the multi-BSSID set, since the wireless communication terminal signals multiple BSSs through one management frame, the amount of time that a data frame can occupy the channel may increase. In a specific embodiment, the wireless communication terminal may set a reference BSSID representing the multi-BSSID set as the BSS information indicated by the management frame, and insert information about the multi-BSSID set into the management frame. The information about the multi-BSSID set may include information related to the maximum number of multiple BSSIDs included in the multi-BSSID set. Specifically, the information about the multi-BSSID set may be Figure 7 (a) the multi-BSSID element. At this time, the information about the multi-BSSID set may include sub-elements. In addition, the ID value for identifying the sub-elements may be the same as Figure 7 (b) the ID value of the embodiment.

[0086] The multi-BSSID element may include an element ID field. The element ID field is an identifier indicating the multi-BSSID element. In addition, the multi-BSSID element may include a length field. The length field is a field indicating the length of the multi-BSSID element. In addition, the multi-BSSID element may indicate a MaxBSSID indicator field. At this time, the MaxBSSID indicator field indicates information related to the maximum number of BSSIDs that the multi-BSSID set may include. Specifically, when the value indicated by the MaxBSSID indicator field is n, the maximum number of BSSIDs that the multi-BSSID set may include is 2 n。The maximum number of BSSIDs is the number including the reference BSSID. In addition, the multi - BSSID element may include an optional sub - element field. The optional sub - element may include information about the BSS indicated by the non - transmitting BSSID. The non - transmitting BSSID indicates a BSSID included in the multi - BSSID set other than the reference BSSID. Specifically, the optional sub - element field may include a non - transmitting BSSID profile, which is information about the BSS indicated by the non - transmitting BSSID. The optional sub - element field may include only information about the BSS indicated by a part of the non - transmitting BSSID. At this time, the wireless communication terminal that receives the management frame may obtain information about the BSS indicated by the remaining non - transmitting BSSIDs based on the beacon frame or the probe response frame. In addition, the wireless communication terminal that receives the management frame may obtain information about the BSS indicated by the remaining non - transmitting BSSIDs by sending a probe request frame.

[0087] The information about the BSS indicated by the non - transmitting BSSID may be an element included in the non - transmitting BSSID capability element and the beacon frame body. Specifically, the element that may be included in the beacon frame body may be at least one of the SSID, the multi - BSSID index sub - element, and the FMD descriptor element. In addition, among the information about the BSS indicated by the non - transmitting BSSID, the information that is the same as the BSS information indicated by the reference BSSID may be omitted. Specifically, at least one of the timestamp and beacon interval fields, DSSS parameter set, IBSS parameter set, country, channel switch announcement, extended channel switch announcement, wide - bandwidth channel switch, transmit power envelope, supported operation class, IBSS DFS, ERP information, HT capability, HT operation, VHT capability, and VHT operation element indicated by the non - transmitting BSSID may be the same as the BSS indicated by the reference BSSID.

[0088] In addition, the optional sub - element field may include a vendor - specific element.

[0089] The wireless communication terminal that receives the management frame including information about the multi - BSSID set may obtain information about the multi - BSSID set from the management frame. At this time, the wireless communication terminal may obtain the BSSIDs included in the multi - BSSID set based on the information about the multi - BSSID set and the reference BSSID. Specifically, the wireless communication terminal may obtain the BSSIDs included in the multi - BSSID set by the following equation.

[0090] BSSID(i) = BSSID_A|BSSID_B

[0091] At this time, BSSID_A is a BSSID in which the (48 - n) most significant bits (MSB) have values equal to the (48 - n) MSB values of the reference BSSID and the n least significant bits (LSB) have values of 0. Additionally, BSSID_B is a BSSID in which the (48 - n) MSB values are 0 and the n LSB values are the remainder (mod) when the sum of the n LSBs of the reference BSSID and i is divided by 2 n at that time.

[0092] Due to the popularity of mobile devices and the provision of wireless communication, wireless communication terminals are increasingly communicating in dense environments. In particular, the number of cases where wireless communication terminals communicate in an environment where multiple BSSs overlap is increasing. When multiple BSSs overlap, the communication efficiency of wireless communication terminals may degrade due to interference from other wireless communication terminals. In particular, when using a frequency band through a contention process, wireless communication terminals may not even be guaranteed a transmission opportunity due to interference from other wireless communication terminals. To solve this problem, wireless communication terminals can perform a spatial reuse (SR) operation. Specifically, the SR operation can include an operation of accessing a channel depending on whether the received frame is a frame sent from the BSS including the wireless communication terminal or a frame sent from another BSS. In a specific embodiment, the operation of accessing a channel can include at least one of a clear channel assessment (CCA) operation, a deferral operation, and a network allocation vector (NAV) setting operation. At this time, NAV represents the time during which radio resources are occupied by the transmission of another wireless communication terminal. The NAV can be maintained regardless of the clear channel assessment (CCA) result. Specifically, the wireless communication terminal can adjust the clear channel assessment (CCA) threshold according to whether the frame received by the wireless communication terminal is a frame sent from the BSS including the wireless communication terminal or a frame sent from an OBSS. At this time, in the case of a frame sent from an OBSS, the wireless communication terminal can apply a larger CCA threshold compared to the CCA threshold applied when sending a frame from the BSS including the wireless communication terminal. At this time, the CCA threshold indicates a reference value for determining whether a channel is busy or idle. In addition, the wireless communication terminal can adjust the transmission power of the physical layer convergence protocol protocol data unit (PPPU) sent during the SR operation. When using a multi - BSSID set, the SR operation of the wireless communication terminal is a problem. When using a multi - BSSID set, the reference Figures 8 to 16 will describe the SR operation of the wireless communication terminal.

[0093] Figure 8 Illustrates the spatial reuse operation of a wireless communication terminal when the wireless communication terminal according to an embodiment of the present invention uses a multi - BSSID set.

[0094] For convenience of explanation, the BSS including the wireless communication terminal is referred to as within the BSS, and the basic service set overlapping with the within the BSS is referred to as the overlapping basic service set (OBSS). In addition, the PPDU transmitted from within the BSS is referred to as the within-BSS PPDU, and the frame transmitted from the OBSS is referred to as the OBSS PPDU or the inter-BSS PPDU. In addition, the frame transmitted within the BSS is referred to as the within-BSS frame, and the frame transmitted in the OBSS is referred to as the OBSS frame or the inter-BSS frame. In addition, when transmitting the within-BSS frame, the magnitude of the CCA threshold applied by the wireless communication terminal is referred to as the general CCA level. When transmitting the inter-BSS frame, the magnitude of the CCA threshold applied by the wireless communication terminal is referred to as the OBSS CCA level. In particular, when transmitting the inter-BSS frame, the magnitude of the CCA threshold used by the wireless communication terminal for preamble detection (PD) is referred to as the OBSS PD level. At this time, the OBSS CCA level may be a value greater than or equal to the general CCA level value.

[0095] As described above, the wireless communication terminal may access a channel based on whether the received PPDU is an in-BSS PPDU or an inter-BSS PPDU. Specifically, the wireless communication terminal may access a channel based on whether the received frame is an in-BSS frame or an inter-BSS frame. When using a multi-BSSID set, the wireless communication terminal may consider multiple BSSs identified by each of multiple BSSIDs included in the same multi-BSSID set as the same BSS. When using a multi-BSSID set, the wireless communication terminal may consider multiple BSSs identified by each of multiple BSSIDs included in the same multi-BSSID set as the same BSS. For convenience of explanation, the BSSID of the BSS including the wireless communication terminal is referred to as the first BSSID, and BSSIDs other than the first BSSID are referred to as second BSSIDs. When the first BSSID is included in a multi-BSSID set including the second BSSID, the wireless communication terminal may determine a frame sent from the BSS identified by the second BSSID as an in-BSS frame. In addition, when the first BSSID is not included in any multi-BSSID set or the second BSSID is not included in a multi-BSSID set including the first BSSID, the wireless communication terminal may determine a frame sent from the BSS identified by the second BSSID as an inter-BSS frame. Specifically, when the first BSSID is included in a multi-BSSID set including the second BSSID and the wireless communication terminal detects a frame sent from the BSS identified by the second BSSID, the wireless communication terminal may apply the CCA threshold as a general CCA level instead of an OBSS CCA level. When the first BSSID is not included in any multi-BSSID set or the second BSSID is not included in a multi-BSSID set including the first BSSID and the wireless communication terminal detects a frame sent from the BSS identified by the second BSSID, the wireless communication terminal may apply the OBSS CCA level as the CCA threshold.

[0096] In Figure 8 the embodiment of (a), the tenth station STA10 is associated with the first virtual access point VAP1, and the twentieth station STA20 is associated with the second virtual access point VAP2. In addition, all BSSs operated by each of the first virtual access point VAP1 to the third virtual access point VAP3 have BSSIDs included in the same multi-BSSID set. At this time, the twentieth station STA20 determines the PPDU sent from the first virtual access point VAP1 as an in-BSS PPDU. Figure 8 The network relationship of the embodiment of (a) is applied as it is to Figure 8 (b), 8(c), and 8(d).

[0097] In addition, the wireless communication terminal may change the NAV setting depending on whether the received frame is an in-BSS frame or an inter-BSS frame. Specifically, the wireless communication terminal may separately maintain the NAV for in-BSS frames and the NAV for inter-BSS frames. At this time, when the wireless communication terminal receives an in-BSS frame, the wireless communication terminal may set or update the NAV for in-BSS frames based on the received in-BSS frame. In addition, when the frame received by the wireless communication terminal cannot be determined as an in-BSS frame or an inter-BSS frame, the wireless communication terminal may update the NAV for inter-BSS frames based on the received frame. In addition, when the wireless communication terminal receives an inter-BSS frame, the wireless communication terminal may set or update the NAV for inter-BSS frames based on the received inter-BSS frame. Therefore, when the first BSSID is included in the multi-BSSID set including the second BSSID and the wireless communication terminal receives a frame sent from the BSS identified by the second BSSID, the wireless communication terminal may set or update the NAV for in-BSS frames based on the frame sent in the BSS identified by the second BSSID. When the first BSSID is not included in any multi-BSSID set or the second BSSID is not included in the multi-BSSID set including the first BSSID and the wireless communication terminal receives a frame sent from the BSS identified by the second BSSID, the wireless communication terminal may set or update the NAV for inter-BSS frames based on the frame sent in the BSS identified by the second BSSID. In a specific embodiment, when the wireless communication terminal receives a CF-END frame from an OBSS, the wireless communication terminal may not reset the NAV set by the in-BSS frame. Therefore, when the first BSSID is included in the multi-BSSID set including the second BSSID and the wireless communication terminal receives a CF-END frame sent from the BSS identified by the second BSSID, the wireless communication terminal may reset the NAV set by the in-BSS frame and maintain the NAV set by the inter-BSS frame as before. When the first BSSID is not included in any of the multi-BSSID sets or the second BSSID is not included in the multi-BSSID set including the first BSSID and the wireless communication terminal receives a CF-END frame sent from the BSS identified by the second BSSID, the wireless communication terminal may reset the NAV set by the inter-BSS frame and maintain the NAV set by the in-BSS frame as before. Specifically, the wireless communication terminal may operate as in the embodiments of Figure 8 (b) and 8(c).

[0098] In Figure 8In the embodiment of (b), the twentieth station STA20 receives a PPDU sent from the first virtual access point VAP1. The BSSID of the BSS that identifies the first virtual access point VAP1 is included in a multi-BSSID set that includes the BSSID of the BSS that identifies the twentieth station STA20. Accordingly, the twentieth station STA20 sets the NAV for in-BSS frames. At this time, the twentieth station STA20 receives a CF-END frame sent from a BSS (OBSS) other than the BSSs operated by the first virtual access point VAP1 to the third virtual access point VAP3. The twentieth station STA20 does not reset the NAV for in-BSS frames.

[0099] In Figure 8 In the embodiment of (c), the twentieth station STA20 receives a PPDU sent from a BSS (OBSS) other than the BSSs operated by the first virtual access point VAP1 to the third virtual access point VAP3. At this time, the twentieth station STA20 sets the NAV based on the received PPDU. The twentieth station STA20 receives a CF-END frame from the first virtual access point VAP1. The BSSID of the BSS that identifies the first virtual access point VAP1 is included in a multi-BSSID set that includes the BSSID of the BSS that identifies the twentieth station STA20. Accordingly, the twentieth station STA20 resets the NAV for in-BSS frames without resetting the NAV for inter-BSS frames.

[0100] When a wireless communication terminal receives a trigger frame for triggering the transmission of the wireless communication terminal, the wireless communication terminal can send a trigger-based PPDU based on the trigger frame regardless of the set NAV. Specifically, when the NAV of the wireless communication terminal is set by the access point that sends the trigger frame, the wireless communication terminal can send a trigger-based PPDU regardless of the set NAV. In another specific embodiment, when the response to the trigger frame includes an ACK frame and the length of the response is limited to be less than a reference value, the wireless communication terminal can send a trigger-based PPDU regardless of the set NAV. In another specific embodiment, when the NAV of the wireless communication terminal is set by an in-BSS frame, the wireless communication terminal can send a trigger-based PPDU regardless of the set NAV. In another specific embodiment, when the BSSID of the BSS in which the frame for setting the NAV of the wireless communication terminal is sent and the BSSID of the BSS that includes the wireless communication terminal are included in the same multi-BSSID set, the wireless communication terminal can send a trigger-based PPDU regardless of the set NAV. Specifically, the wireless communication terminal can operate as in Figure 8 the embodiment of (d).

[0101] In Figure 8In the embodiment of (d), the twentieth station STA20 receives a PPDU sent by the first virtual access point VAP1. The BSSID of the BSS that identifies the first virtual access point VAP1 is included in a multi-BSSID set that includes the BSSID of the BSS that identifies the twentieth station STA20. Therefore, the twentieth station STA20 sets the NAV for the in-BSS frames based on the received PPDU. The twentieth station STA20 receives a CF-END frame from the first virtual access point VAP1 but fails to decode the CF-END. The twentieth station STA20 receives a trigger frame from the second virtual access point VAP2. The NAV set in the twentieth station STA20 is set based on the PPDU sent by the first virtual access point AP, and the BSSID of the BSS that identifies the first virtual access point VAP1 is included in a multi-BSSID set that includes the BSSID of the BSS that identifies the twentieth station STA20. Therefore, the twentieth station STA20 can send a trigger-based PPDU regardless of the set NAV.

[0102] A wireless communication terminal can determine whether a received frame is an inter-BSS frame or an in-BSS frame based on the BSS color signaled in the physical layer of the received frame. At this time, the BSS color is information for identifying a BSS. Specifically, when the BSS color that identifies the BSS including the wireless communication terminal is the same as the BSS color signaled in the physical layer of the received frame, the wireless communication terminal can determine the received frame as an in-BSS frame. In addition, when the BSS color that identifies the BSS including the wireless communication terminal and the BSS color signaled in the physical layer of the received frame are different, the wireless communication terminal can determine the received frame as an inter-BSS frame. In addition, the wireless communication terminal can determine whether a received frame is an inter-BSS frame or an in-BSS frame based on the MAC address signaled in the MAC layer of the received frame. Specifically, the wireless communication terminal can determine whether a received frame is an inter-BSS frame or an in-BSS frame based on the address field of the received frame. When the MAC address signaled in the MAC layer in a specific embodiment matches the MAC address or BSSID of the access point operating the BSS including the wireless communication terminal, the wireless communication terminal can determine the received frame as an in-BSS frame. At this time, the MAC address signaled in the MAC layer can include an individual / group bit signaling indicating whether the MAC address is a group MAC address. In this case, the wireless communication terminal can determine that the value obtained by excluding the individual / group bit from the MAC address signaled in the MAC layer matches the MAC address of the access point operating the BSS including the wireless communication terminal or the BSSID of the BSS including the wireless communication terminal.

[0103] Therefore, in order to consider multiple BSSs identified by each of multiple BSSIDs included in the same multi - BSSID set as the same BSS during the SR operation of a wireless communication terminal, it is necessary to determine information related to BSS color and MAC address. Specifically, the wireless communication terminal compares the MAC address signaled in the MAC layer of the received frame with the multi - BSSID set including the BSSID of the BSS containing the wireless communication terminal, and determines whether the received frame is an intra - BSS frame or an inter - BSS frame. In a specific embodiment, when the MAC address signaled in the MAC layer of the received frame matches any one of the multiple BSSIDs included in the multi - BSSID set (including the BSSID of the BSS containing the wireless communication terminal), the wireless communication terminal may determine the received frame as an intra - BSS frame. In another specific embodiment, when the MAC address signaled in the MAC layer of the received frame does not match any one of the multiple BSSIDs included in the multi - BSSID set (including the BSSID of the BSS containing the wireless communication terminal), the terminal may determine the received frame as an inter - BSS frame. At this time, the wireless communication terminal may obtain information about the multi - BSSID set from the management frame as described above. Specifically, the information about the multi - BSSID set may be the multi - BSSID set element described above.

[0104] In addition, the BSS corresponding to each of the multiple BSSIDs included in the same multi - BSSID set may be set to the same BSS color. Specifically, each of the multiple access points operating the BSS corresponding to each of the multiple BSSIDs included in the same multi - BSSID set may set the BSS color value of the BSS corresponding to the multiple BSSIDs to be the same. At this time, the multiple BSSs corresponding to the multi - BSSID set may be operated by one wireless communication terminal. In another specific embodiment, the BSS color corresponding to the multiple BSSIDs included in the multi - BSSID set may be signaled. Specifically, the access point may signal the BSS color corresponding to the multiple BSSIDs included in the multi - BSSID set. The BSS color setting method and BSS color signaling method for the multi - BSSID set will be described with reference to Figures 9 to 12 Describe the BSS color setting method and BSS color signaling method for the multi - BSSID set.

[0105] Figure 9 Show a network for a virtual LAN according to an embodiment of the present invention.

[0106] As described above, the BSS color values of multiple BSSs corresponding to a multi-BSSID set can all be set to the same. At this time, the multiple BSSs corresponding to the multi-BSSID set represent multiple BSSs identified by multiple BSSIDs included in the multi-BSSID set. Specifically, multiple access points for each of the multiple BSSs corresponding to multiple BSSIDs can all set the same BSS color. The BSS color can be signaled through a signaling field in the physical layer. Specifically, the BSS color can be signaled through the HE-SIG-A field. As described above, a wireless communication terminal can perform an SR operation based on the BSS color. Specifically, the wireless communication terminal can access a channel based on the BSS color. In addition, the wireless communication terminal can perform a power saving operation based on the BSS color.

[0107] In Figure 9 's embodiment, the BSSs operated by the first virtual access point VAP1 to the third virtual access point VAP3 all have the same BSS color value X. All other settings of the network are the same as those in Figure 6 . Specific power saving operations will be described with reference to Figure 10 , and specific CCA operations will be described with reference to Figure 11 and Figure 12 .

[0108] Figure 10 FIG. shows the power saving operation of a wireless communication terminal according to an embodiment of the present invention.

[0109] When the receiver of a frame within a BSS is not the wireless communication terminal, the wireless communication terminal can enter a power saving state to save power. At this time, the power saving state can be referred to as a doze state. Specifically, the power saving state can indicate that a certain function is inactive to save power. In a specific embodiment, when the frame received by the wireless communication terminal is a frame within the BSS and the receiver of the frame received by the wireless communication terminal is not the wireless communication terminal, the wireless communication terminal can enter a power saving state. For example, when the BSS color signaled through the PPDU received by the wireless communication terminal is the same as the BSS color of the wireless communication terminal and the receiver of the frame included in the received PPDU is not the wireless communication terminal, the wireless communication terminal can enter a power saving state.

[0110] In the case where the BSS color values of multiple BSSs corresponding to a multi-BSSID set are all set to the same, even when the wireless communication terminal receives a PPDU sent from a BSS identified by a BSSID included in the multi-BSSID set, the wireless communication terminal can enter a power saving state, and the multi-BSSID set includes the BSSID of the BSS including the wireless communication terminal except for the BSS including the wireless communication terminal.

[0111] In Figure 10In an embodiment, the first case, Case 1, is a case where the BSS color values of multiple BSSs corresponding to a multi-BSSID set are not all set to be the same, and the second case, Case 2, is a case where the BSS color values of multiple BSSs corresponding to a multi-BSSID set are all set to be the same. At this time, the access point AP of the BSS identified by the second BSSID BSSID(2) and the station STA including BSSID(2) in the BSS identified by the second BSSID BSSID(2) transmit / receive PPDUs. At this time, in the first case, Case 1, the station STA including BSSID(1) in the BSS identified by the first BSSID BSSID(1) other than the second BSSID BSSID(2) may not enter the power saving state. However, in the second case, Case 2, the station STA including BSSID(1) in the BSS identified by the first BSSID BSSID(1) that is not the second BSSID BSSID(2) may check the BSS color signaled by the PPDU and enter the power saving state. When using a multi-BSSID set through this operation, the wireless communication terminal can improve power efficiency.

[0112] Figure 11 Illustrates the channel access operation of a wireless communication terminal according to an embodiment of the present invention.

[0113] As described above, the wireless communication terminal can adjust the CCA threshold according to whether the received frame is an inter-BSS frame or an intra-BSS frame. Specifically, when the received frame is an inter-BSS frame, the wireless communication terminal may apply the OBSS CCA level instead of the general CCA level as the CCA threshold. At this time, the OBSS CCA level may be a value greater than or equal to the general CCA level. For the convenience of explanation, the BSSID of the BSS including the wireless communication terminal is referred to as the first BSSID, and the BSSID other than the first BSSID is referred to as the second BSSID. When the BSS color values of multiple BSSs corresponding to a multi-BSSID set are all set to be the same and the first BSSID is included in the multi-BSSID set including the second BSSID, even when the wireless communication terminal receives a PPDU sent from the BSS identified by the second BSSID, the general CCA level instead of the OBSS CCA level may be applied as the CCA threshold. The specific operation of the wireless communication terminal will be described with reference to Figure 11 Describe the specific operation of the wireless communication terminal.

[0114] In Figure 11In an embodiment, in the first case, Case 1 is the case where the BSS color values of multiple BSSs corresponding to a multi-BSSID set are not all set to the same value, and in the second case, Case 2 is the case where the BSS color values of multiple BSSs corresponding to a multi-BSSID set are all set to the same value. At this time, the PPDU is sent from the BSS identified by the second BSSID, BSSID(2). At this time, the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1) which is not the second BSSID, BSSID(2) determines the BSS color signaled by the PPDU. Specifically, the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1) can obtain the BSS color from the signaling field of the PPDU. At this time, the signaling field can be the HE-SIG-A field. In the first case, Case 1, since in the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1), the BSS color obtained from the signaling field of the PPDU is different from the BSS color identified by the first BSSID, BSSID(1), the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1) applies the OBSS PD CCA level to the CCA threshold. Since the received signal strength (RSSI) value is less than the OBSS PD CCA level, the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1) accesses the channel. Specifically, the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1) determines that the channel is idle. In the second case, Case 2, since in the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1), the BSS color obtained from the signaling field of the PPDU is the same as the BSS color of the BSS identified by the first BSSID, BSSID(1), the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1) applies the general PD CCA level to the CCA threshold. Since the received signal strength (RSSI) value is greater than the general CCA level, the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1) does not access the channel. Specifically, the station STA including BSSID(1) in the BSS identified by the first BSSID, BSSID(1) determines that the corresponding channel is busy. Through this operation, the wireless communication terminal can prevent transmission conflicts between BSSs corresponding to the same multi-BSSID set.

[0115] In addition, as described above, the wireless communication terminal may determine whether the received frame is an inter-BSS frame or an intra-BSS frame based on the MAC address signaled in the MAC layer of the received frame. In particular, when a conventional PPDU that does not signal the BSS color in the physical layer is transmitted, the wireless communication terminal may determine whether the received frame is an inter-BSS frame or an intra-BSS frame based on the MAC address signaled in the MAC layer of the received frame. At this time, the wireless communication terminal may consider multiple BSSs corresponding to the same multi-BSSID as the same BSS as described above.

[0116] When the BSS color values of multiple BSSs corresponding to a multi-BSSID set are all set to be the same, the system complexity can be reduced compared to the case of signaling the BSS color corresponding to multiple BSSIDs included in the multi-BSSID set. In addition, the range of values that the BSS color can have can be smaller than the range of values that the BSSID can have. At this time, when the BSS color values of multiple BSSs corresponding to a multi-BSSID set are all set to be the same, the situation where different BSSs do not correspond to the same multi-BSSID set but have the same BSS color value can be reduced.

[0117] In another specific embodiment, when the specified BSS color is signaled in the physical layer of the received frame, the wireless communication terminal may determine whether the received frame is an inter-BSS frame or an intra-BSS frame based on the MAC address signaled in the MAC layer.

[0118] Figure 12 FIG. shows a channel access operation of a wireless communication terminal according to another embodiment of the present invention.

[0119] For convenience of explanation, the BSSID of the BSS including the wireless communication terminal is referred to as the first BSSID, and different BSSIDs are referred to as the second BSSID. When the first BSSID is included in a multi-BSSID set including the second BSSID and the wireless communication terminal receives a PPDU transmitted from the BSS identified by the second BSSID, the wireless communication terminal may not access the corresponding channel regardless of the received signal strength. Specifically, the wireless communication terminal may not access the corresponding channel while the PPDU transmitted from the BSS identified by the second BSSID is being transmitted. At this time, the wireless communication terminal may enter a power-saving state. In addition, the wireless communication terminal may determine that the channel state is busy until it determines that the received PPDU is an inter-BSS frame or an intra-BSS frame.

[0120] In Figure 11In the embodiments described, the wireless communication terminal may determine whether to access a channel based on the received signal strength. However, it is highly likely that a single wireless communication terminal operates multiple BSSs corresponding to a multi-BSSID set. Therefore, even when the wireless communication terminal accesses the channel and transmits data while a PPDU is being transmitted from the BSS identified by the second BSSID, the access point of the BSS including the wireless communication terminal may not receive the PPDU. Finally, it may be effective to restrict the transmission of the wireless communication terminal when a PPDU is being transmitted from the BSS identified by the second BSSID regardless of the strength of the received signal.

[0121] In Figure 12 the embodiment, the PPDU is transmitted from the BSS identified by the second BSSID BSSID(2). At this time, the station STA including BSSID(1) in the BSS identified by the first BSSID BSSID(1) which is not the second BSSID BSSID(2) determines the BSS color signaled by the PPDU. Specifically, the station STA including BSSID(1) in the BSS identified by the first BSSID BSSID(1) may obtain the BSS color from the signaling field of the PPDU. Since the BSS color obtained from the signaling field of the PPDU in the station STA including BSSID(1) in the BSS identified by the first BSSID BSSID(1) is the same as the BSS color of the BSS identified by the first BSSID BSSID(1), the station STA including BSSID(1) in the BSS identified by the first BSSID BSSID(1) does not access the corresponding channel regardless of the strength of the received signal. Specifically, the station STA including BSSID(1) in the BSS identified by the first BSSID BSSID(1) determines that the corresponding channel is busy regardless of the strength of the received signal. By this operation, the wireless communication terminal can prevent transmission conflicts between BSSs corresponding to the same multi-BSSID set.

[0122] Figure 13 A method of setting BSS color values for multiple BSSs corresponding to a multi-BSSID set according to an embodiment of the present invention is shown.

[0123] The BSS colors of multiple BSSs corresponding to a multi - BSSID set can be set to different values. The multiple access points of each of the multiple BSSs corresponding to the multi - BSSID set can set the BSS color values of the multiple BSSs corresponding to the multi - BSSID set differently. In a specific embodiment, only some of the multiple BSSs corresponding to the multi - BSSID set can be set to different BSS color values. At this time, a wireless communication terminal of a BSS corresponding to the multi - BSSID set can determine whether the recipient of the received PPDU is the wireless communication terminal by decoding a signaling field of the physical layer. Therefore, the wireless communication terminal can determine that the recipient of the PPDU received faster than the case where the BSS color values of the multiple BSSs corresponding to the multi - BSSID set are set to the same in the received PPDU is the wireless communication terminal. When the recipient of the received PPDU is not the wireless communication terminal, the wireless communication terminal can stop decoding. At this time, the wireless communication terminal can refrain from accessing the corresponding channel based on at least one of the PPDU length, TXOP length, and bandwidth of the PPDU to protect the PPDU being transmitted.

[0124] At this time, the access point can explicitly signal the BSS color values of the multiple BSSs corresponding to the multi - BSSID set. In another specific embodiment, the BSS color values for the multiple BSSs corresponding to the multi - BSSID set can be set according to a predetermined rule. Specifically, among the BSS color values of the multiple BSSs corresponding to the multi - BSSID, one or more bit values corresponding to the same position can be the same. For example, among the BSS color values of the multiple BSSs corresponding to the multi - BSSID set, the n most significant bits (MSBs) can be the same. For example, among the BSS color values of the multiple BSSs corresponding to the multi - BSSID set, the n least significant bits (LSBs) can be the same. In a specific embodiment, the value of n can be determined according to the number of BSSIDs included in the multi - BSSID set.

[0125] In Figure 13 (a), three BSSs corresponding to the multi - BSSID set have different BSS color values. All other settings of the network are the same as Figure 9 in. At this time, as shown in Figure 13 (b), the BSS color value can be indicated by 6 bits. Therefore, the BSS color value can be in the range of 0 to 63. At this time, among the BSS color values of the multiple BSSs corresponding to the same multi - BSSID set, the n MSBs are the same.

[0126] In addition, multiple access points each operating multiple BSSs corresponding to a multi-BSSID set may set BSS color values for the multiple BSSs corresponding to the multi-BSSID set based on BSSID values. Specifically, multiple access points each operating multiple BSSs corresponding to multiple BSSIDs may set the LSB to a BSS color value that is as many bits as the number of bits that the BSS color value may have in the BSSID value. At this time, the wireless communication terminal may obtain, as the BSS color value corresponding to the BSSID, as many LSBs as the number of bits that the BSS color value may have from the bit value of the BSSID. That is, the wireless communication terminal may obtain the BSS color value corresponding to the BSSID through BSSID % 2 n to obtain the BSS color value corresponding to the BSSID. In this case, when the wireless communication terminal does not have a BSSID included in the multi-BSSID set, it may obtain the BSS color value corresponding to each BSSID. Therefore, separate signaling for the BSS color values of the multiple BSSs corresponding to the multi-BSSID set is not required.

[0127] In another specific embodiment, multiple access points each operating each of the multiple BSSs corresponding to a multi-BSSID set may set BSS color values for the multi-BSSID set based on a reference BSSID. Specifically, multiple access points each operating each of the multiple BSSs corresponding to multiple BSSIDs set, as the color value corresponding to the corresponding BSSID, a value obtained by adding the difference between the reference BSSID and the corresponding BSSID to the BSS color value corresponding to the reference BSSID of the multi-BSSID set.

[0128] As described above, the range of values that the BSS color may have may be smaller than the range of values that the BSSID may have. At this time, when the BSS color values of the multiple BSSs corresponding to the multi-BSSID set are all set differently, BSSs that do not correspond to the same multi-BSSID set and are different from each other are more likely to have the same BSS color value. Therefore, when the BSS color values of the multiple BSSs corresponding to the multi-BSSID set are all set differently, the wireless communication terminal may perform an SR operation after checking the MAC address signaled in the MAC layer of the received frame. At this time, the wireless communication terminal may determine whether the received frame is an inter-BSS frame or an intra-BSS frame based on the MAC address signaled in the MAC layer of the received frame. In addition, the SR operation may include at least one of the above-described channel access operation and power saving operation.

[0129] As described above, the wireless communication terminal may determine whether the received frame is an inter-BSS frame or an intra-BSS frame based on the MAC address. At this time, refer to Figures 14 to 15Describe a specific method for determining whether a frame received by a wireless communication terminal is an inter-BSS frame or an intra-BSS frame, and a power-saving operation of the wireless communication terminal.

[0130] Figure 14 Illustrate a situation where a wireless communication terminal according to an embodiment of the present invention enters a power-saving state based on the MAC header of a frame received by the wireless communication terminal. Additionally, Figure 15 Illustrate a situation where a wireless communication terminal according to an embodiment of the present invention enters a power-saving state based on the MAC header of a frame received by the wireless communication terminal when the wireless communication terminal is included in a BSS corresponding to a multi-BSSID set.

[0131] When the transmitter address TA or the receiver address RA indicated by the MAC header of the received frame corresponds to another BSSID of a multi-BSSID set including the BSSID of the BSS containing the wireless communication terminal, the wireless communication terminal may determine the received frame as an intra-BSS frame. When the frame received by the wireless communication terminal is an intra-BSS frame and the wireless communication terminal is not the recipient of the received frame, the wireless communication terminal may enter a power-saving state. At this time, the wireless communication terminal may maintain the power-saving state until the end of the duration of the PPDU including the received frame.

[0132] In Figure 14 the embodiment, the first station STA1 and the second station STA2 are associated with the same access point AP. When the access point AP sends a PPDU to the first station STA1, the second station STA2 may receive the PPDU. At this time, the second station STA2 determines whether the received PPDU is an intra-BSS frame. When the received PPDU is an intra-BSS frame, the second station STA2 determines whether the recipient of the received PPDU is the second station STA2. Specifically, the second station STA2 may determine whether the recipient of the received PPDU is the second station STA2 based on the MAC header. At this time, when the second station STA2 is not the recipient of the received PPDU, the second station STA2 may enter a power-saving state.

[0133] When entering the power-saving state, the wireless communication terminal may determine whether the receiver address RA of the frame indicates a plurality of wireless communication terminals including the corresponding wireless communication terminal. Specifically, when the received frame is an intra-BSS frame, the receiver address RA of the received frame is not the MAC address of the wireless communication terminal, and the receiver address RA of the received frame does not correspond to the broadcast address, the wireless communication terminal may enter a power-saving state. At this time, when the receiver address RA of the received frame does not correspond to the multicast address that the wireless communication terminal should receive and the receiver address (RA) of the received frame does not correspond to the group address that the wireless communication terminal should receive, the wireless communication terminal may enter a power-saving state.

[0134] In a specific embodiment, even when the receiver address RA of a trigger frame or the receiver address RA of a multi-station block ACK (Multi-STA Block ACK) frame does not match the MAC address of a wireless communication terminal, the wireless communication terminal may need to receive the trigger frame or the multi-station block ACK frame. Specifically, when the recipient of a trigger frame is multiple wireless communication terminals, the receiver address RA of the trigger frame can be a broadcast address. At this time, the number of user information fields of the trigger frame can be two or more. Additionally, when the recipient of a multi-station block ACK frame is multiple wireless communication terminals, the receiver address RA of the multi-station block ACK can be a broadcast address. At this time, the number of AID fields in each STA information sub-field of the multi-station block ACK can be two or more. At this time, the broadcast address can indicate multiple wireless communication terminals or one wireless communication terminal.

[0135] Therefore, when the received frame is an in-BSS frame, the receiver address RA of the received frame is not the MAC address of the wireless communication terminal, the received frame is a trigger frame, and the receiver address RA of the received frame does not correspond to a broadcast address, the wireless communication terminal can enter a power-saving state. In addition, when the received frame is an in-BSS frame, the receiver address RA of the received frame is not the MAC address of the wireless communication terminal, the received frame is a trigger frame, and the receiver address RA of the multi-station block ACK frame does not correspond to a broadcast address, the wireless communication terminal can enter a power-saving state.

[0136] Specifically, when the recipient of a trigger frame or a multi-station block ACK frame is multiple wireless communication terminals, the receiver address RA can be a multicast address or a group address. Therefore, when the wireless communication terminal receives a trigger frame or a multi-station block ACK frame and the receiver address RA of the received frame is not a multicast address and a group address including the wireless communication terminal, the wireless communication terminal can enter a power-saving state.

[0137] When any one of the BSSIDs included in a multi-BSSID set is set as the receiver address RA or the transmitter address TA of a frame, only the wireless communication terminals included in the BSS identified by the corresponding BSSID can be the recipient or transmitter of the corresponding frame. Specifically, for a frame sent to a plurality of wireless communication terminals included in each of two or more BSSs corresponding to a multi-BSSID set, a modified value can be set based on the BSSID in the transmitter address of the frame. At this time, the wireless communication terminal may not separately determine whether the receiver address RA and the transmitter address TA are a broadcast address or a multicast address including the address of the wireless communication terminal. For the convenience of description, the BSSID of the BSS including the wireless communication terminal is referred to as the first BSSID, and different BSSIDs other than the first BSSID are referred to as the second BSSID. Specifically, when the second BSSID is included in the multi-BSSID set including the first BSSID and the receiver address RA or the transmitter address TA of the frame received by the wireless communication terminal matches the second BSSID, the wireless communication terminal can enter the power saving state.

[0138] In Figure 15 the embodiment of, the multi-BSSID set includes the first BSSID BSSID(1) and the second BSSID BSSID(2). The first station STA1 is included in the BSS identified by the second BSSID BSSID(2), and the second station STA2 is included in the BSS identified by the first BSSID BSSID(1). At this time, the virtual access point having the second BSSID BSSID(2) sends a PPDU to the first station STA1. The second station STA2 receives the corresponding PPDU. The second station STA2 determines whether the received PPDU is an in-BSS frame. Specifically, the second station STA2 can determine whether the MAC address signaled by the MAC header of the received PPDU is the BSSID of the multi-BSSID set including the first BSSID. Since the transmitter address TA of the received PPDU is the second BSSID BSSID(2), the second station STA2 determines the received PPDU as an in-BSS frame. In addition, since the receiver of the received PPDU is a wireless communication terminal included in the BSS identified by the second BSSID BSSID(2), the second station STA2 enters the power saving state.

[0139] When the received PPDU is an inter-BSS frame, the second station STA2 determines whether the recipient of the received PPDU is the second station STA2. Specifically, the second station STA2 can determine whether the recipient of the received PPDU based on the MAC header is the second station STA2. At this time, when the second station STA2 is not the recipient of the received PPDU, the second station STA2 can enter the power saving state.

[0140] In another specific embodiment, when the reference BSSID is set as the transmitter address (TA) of a frame, it may indicate that the transmitter address TA is sent to a plurality of wireless communication terminals included in two or more BSSs corresponding to a multi-BSSID set. When a second BSSID is included in the multi-BSSID set including the first BSSID, the second BSSID is not the reference BSSID, and the receiver address RA or the transmitter address TA of the frame received by the wireless communication terminal indicates that the frame is sent from the second BSSID, the wireless communication terminal may enter a power saving state.

[0141] When using a multi-BSSID set, the wireless communication terminal can improve the transmission efficiency of other types of frames as well as management frames. This will be Figures 16 to 18 described herein.

[0142] Figure 16 A method of displaying an identifier of a wireless communication terminal included in a plurality of BSSs corresponding to a multi-BSSID set according to an embodiment of the present invention is shown.

[0143] The wireless communication terminal can signal the reception of data by the wireless communication terminal by using a signaling field of the physical layer. Specifically, the wireless communication terminal can signal the reception of data by the wireless communication terminal through transmission using MU-MIMO by using a signaling field of the physical layer. In addition, the wireless communication terminal can signal the reception of data by using a traffic indication map (TIM). In this case, a method of signaling one or more wireless communication terminals included in a BSS corresponding to a plurality of BSSIDs may be a problem.

[0144] The wireless communication terminal can use a bitmap to signal a plurality of wireless communication terminals included in a BSS corresponding to a plurality of BSSIDs. Each bit of the bitmap indicates a wireless communication terminal, and when the value of the bit is 1, the bitmap signals the wireless communication terminal corresponding to the corresponding bit. At this time, the bitmap can be mapped to the associated identifier (AID) of the wireless communication terminal. In addition, a plurality of wireless communication terminals operating a plurality of BSSs corresponding to a multi-BSSID set can assign bits of the bitmap from 0 to X to a plurality of wireless communication terminals included in a plurality of BSSs corresponding to the multi-BSSID set. In this case, X may be a value obtained by subtracting 1 from the maximum value of BSSIDs that can be included in the multi-BSSID set. Specifically, X may be 2 n-1, and n can be the value of the MaxBSSID indicator field as described above. At this time, when signaling multiple wireless communication terminals included in any one of the multiple BSSs corresponding to the multi-BSSID set, the wireless communication terminal can set the bit of the association identifier of the wireless communication terminal operating the corresponding BSS to 1. At this time, the specific form of the bitmap can be the same as that of Figure 16 the embodiment of (a). In addition, the specific bits of the bitmap can indicate all wireless communication terminals included in the multiple BSSs corresponding to the multi-BSSID set. At this time, the specific bits can be the bits corresponding to the association identifier 2007.

[0145] When using the above method, the wireless communication terminal should signal all wireless communication terminals included in one of the multiple BSSs corresponding to the multi-BSSID set or signal all wireless communication terminals included in the multiple BSSs corresponding to the multi-BSSID set. Therefore, the combination of wireless communication terminals that the wireless communication terminal can signal can be restricted. Therefore, the wireless communication terminal can allocate some bits of the above bitmap as group bits indicating a group of wireless communication terminals. At this time, the group can be a group including some BSSs among the multiple BSSs corresponding to the multi-BSSID set. Additionally, the group can be a group including some of the multiple wireless communication terminals included in the multiple BSSs corresponding to the multi-BSSID set. At this time, the specific form of the bitmap can be the same as that of Figure 16 the embodiment of (a).

[0146] In addition, the wireless communication terminal can use the AID allocation method of the multi-BSSID TIM operation to reduce the bitmap size. Specifically, it can utilize Figure 16 (a) and Figure 16 (b)'s bitmap control fields. Additionally, when the maximum number of groups that the wireless communication terminal can use is restricted, it is possible to send the bitmap that can be allocated to the groups without sending the bitmap corresponding to the remaining association identifiers. The wireless communication terminal can send the bitmap through the association response frame and the re-association response frame. In addition, the wireless communication terminal can signal information about the group through the management frame or the action frame. Specifically, the wireless communication terminal can signal the association identifier corresponding to the group through the association response frame and the re-association response frame.

[0147] Figure 17 Shows the trigger frame format according to an embodiment of the present invention.

[0148] The wireless communication terminal can trigger the transmission of multiple wireless communication terminals by sending a trigger frame. The specific format of the trigger frame can be the same as that of Figure 17The format of the embodiments is the same. The trigger frame may include a transmitter address field A2 indicating the transmitter address, which is the address of the wireless communication terminal that sends the trigger frame. Since it is common for a wireless communication terminal operating a BSS to send a trigger frame, it is common for the transmitter address of the trigger frame to be set to the BSSID of the BSS that sends the trigger frame.

[0149] A wireless communication terminal can trigger the transmission of multiple wireless communication terminals included in multiple BSSs corresponding to a multi-BSSID set through one trigger frame. Specifically, the wireless communication terminal can trigger the transmission of multiple wireless communication terminals included in multiple BSSs corresponding to a multi-BSSID set by setting the transmitter address of the trigger frame to a reference BSSID. However, in this embodiment, the case of triggering multiple wireless communication terminals included in the BSS corresponding to the reference BSSID and the case of triggering multiple wireless communication terminals included in multiple BSSs corresponding to a multi-BSSID set may not be distinguished from each other. To prevent this, the wireless communication terminal can set the individual / group of the reference BSSID to 1. Therefore, the wireless communication terminal can set the reference BSSID with individual / group being 1 as the transmitter address to trigger the transmission of multiple wireless communication terminals included in multiple BSSs corresponding to a multi-BSSID set.

[0150] In another specific embodiment, the wireless communication terminal sets the value of n least significant bits (LSBs) set to 0 in the reference BSSID as the transmitter address to trigger the transmission of multiple wireless communication terminals included in multiple BSSs corresponding to a multi-BSSID set. In this case, n can be the value of the above-mentioned MaxBSSID indicator field. However, when there is a BSS with the value of n LSBs set to 0 in the reference BSSID as the BSSID, confusion may occur for the BSS indicated by the transmitter address.

[0151] Figure 18 Shows the trigger frame format according to another embodiment of the present invention.

[0152] In Figure 17In an embodiment, when the transmitter address of a trigger frame indicates multiple BSSs corresponding to a multi-BSSID set, it is necessary to check that all wireless communication terminals included in the multiple BSSs corresponding to the multi-BSSID set trigger the transmission of corresponding wireless communication terminals through the trigger frame. The wireless communication terminal signals the BSS including the terminal triggered by the transmitter address of the trigger frame to trigger the transmission of wireless communication terminals included in some of the multiple BSSs corresponding to the multi-BSSID set. Specifically, the wireless communication terminal can set the transmitter address of the trigger frame to any one of the multiple BSSIDs included in the multi-BSSID set. By this, the wireless communication terminal can trigger the transmission of multiple wireless communication terminals included in the BSS identified by a BSSID having a value greater than the corresponding BSSID among the multiple BSSIDs included in the multi-BSSID set. In another embodiment, the wireless communication terminal can trigger the transmission of multiple wireless communication terminals included in the BSS identified by a BSSID having a value less than the corresponding BSSID among the multiple BSSIDs included in the multi-BSSID set.

[0153] At this time, the wireless communication terminal can send signaling information indicating the trigger of the transmission of wireless communication terminals included in some BSSs among the multiple BSSs corresponding to the multi-BSSID set. Specifically, by using a signaling field set to 0 when the wireless communication terminal sends a control frame, the wireless communication terminal can send the signaling information. Specifically, the wireless communication terminal can send the signaling information by setting the sequence subfield of the frame control field in the MAC frame format to 1. In another specific embodiment, the wireless communication terminal can send the signaling information by setting the individual / group bit of the receiver address or the transmitter address to 0. In another specific embodiment, the wireless communication terminal can set the control frame to 0 and set the To DS or From DS subfield of the frame control field in the MAC frame format to 1 to send the signaling information.

[0154] The wireless communication terminal sets the transmitter address of the trigger frame to one of the multiple BSSIDs included in the multi-BSSID set and signals an offset value. By this, the wireless communication terminal can trigger the transmission of wireless communication terminals included in the BSS corresponding to the BSSID offset by the offset value among the multiple BSSIDs included in the multi-BSSID set. At this time, the wireless communication terminal can signal the offset by combining several 1-bit fields used in the above transmission methods of the signaling information.

[0155] In another specific embodiment, the wireless communication terminal may signal the BSS including the wireless communication terminal triggered by the trigger frame by setting the receiver address of the trigger frame according to the bitmap to which a plurality of BSSIDs included in the multi - BSSID set are mapped. At this time, the wireless communication terminal may set the bit corresponding to the BSS including the triggered wireless communication terminal in the bitmap to 1. The specific trigger frame format may be the same as that in Figure 18 the same.

[0156] Figure 19 shows a trigger frame format according to another embodiment of the present invention.

[0157] The wireless communication terminal that receives the trigger frame may send a trigger - based PPDU. At this time, the non - associated wireless communication terminal may receive the trigger frame and send a trigger - based PPDU. When the wireless communication terminal that receives the trigger frame sends a trigger - based PPDU, the wireless communication terminal that receives the trigger frame may signal the BSS color through the signaling field of the physical layer of the PPDU. The non - associated wireless communication terminal may set the BSS color value indicated by the signaling field based on the BSS color signaled in the physical layer of the trigger frame. However, when the PPDU including the trigger frame is a legacy PPDU, the BSS color in the signaling field of the PPDU including the trigger frame may not be signaled. Therefore, the wireless communication terminal may signal the BSS color in the MAC layer of the trigger frame. Accordingly, the wireless communication terminal that receives the trigger frame may signal the BSS color value signaled in the MAC layer of the trigger frame through the signaling field of the trigger - based PPDU. Specifically, the wireless communication terminal may signal the BSS color in the common information field of the MAC layer of the trigger frame. At this time, the common information field is a field for signaling information that is commonly applied to a plurality of wireless communication terminals triggered by the trigger frame. In a specific embodiment, when the wireless communication terminal sends a trigger frame that allows random access, the wireless communication terminal may signal the BSS color in the MAC layer of the trigger frame. For example, when the wireless communication terminal sends a trigger frame that allows random access to a non - associated wireless communication terminal, the wireless communication terminal may signal the BSS color in the MAC layer of the trigger frame. In addition, when the BSS color is signaled in the MAC layer of the trigger frame, the wireless communication terminal that receives the trigger frame may determine the trigger frame as a trigger frame for random access. Specifically, when the BSS color is signaled in the MAC layer of the trigger frame, the wireless communication terminal that receives the trigger frame may determine the corresponding trigger frame as a trigger frame for random access of the non - associated wireless communication terminal.

[0158] Additionally, a wireless communication terminal can signal whether to signal BSS color in the MAC layer of a trigger frame through the physical layer of the trigger frame. Specifically, the wireless communication terminal can change the value of the duration field in the MAC layer of the trigger frame to signal whether to signal BSS color in the MAC layer of the trigger frame. In a specific embodiment, when signaling BSS color in the MAC layer of the trigger frame, the wireless communication terminal can set the value of the duration field in the MAC layer to be larger compared to the value of the duration field in the MAC layer set when not signaling BSS color in the MAC layer of the trigger frame. In another specific embodiment, the wireless communication terminal can change the indication bit of the frame control (FC) in the MAC layer of the trigger frame to signal whether to signal BSS color in the MAC layer of the trigger frame.

[0159] Figure 20 Illustrates the OFDMA backoff operation of a wireless communication terminal according to an embodiment of the present invention.

[0160] Multiple wireless communication terminals can use orthogonal frequency division multiple access (OFDMA) to send data to any one of these wireless communication terminals. At this time, multiple wireless communication terminals can send data to any one of these wireless communication terminals based on a trigger frame. In a specific embodiment, the trigger frame can signal the frequency band to which multiple wireless communication terminals can randomly access. At this time, multiple wireless communication terminals can use random values to distribute the access of multiple wireless communication terminals. Specifically, each of the multiple wireless communication terminals can obtain a random value in the OFDMA contention window (OCW) and set the random value as the OFDMA backoff (OBO) counter. At this time, the OCW is a natural number. In a specific embodiment, the OCW can be adjusted according to the channel access method and service characteristics. Multiple wireless communication terminals can decrease the OBO counter value by the number of resource units (RUs) for which random access is signaled by the trigger frame. At this time, the RU can indicate the unit of the frequency band to which a wireless communication terminal can access for data transmission. When the OBO counter value reaches 0, the wireless communication terminal can access the RU for which random access is signaled by the trigger frame. When there are multiple RUs for which random access is allowed, the wireless communication terminal can randomly select any one of the multiple RUs for which random access is allowed. Additionally, when the wireless communication terminal sends a trigger frame, the wireless communication terminal can assign a predetermined association identifier (AID) value to the RU for which random access is allowed.

[0161] A wireless communication terminal may reduce an OBO counter value based on a BSS including the wireless communication terminal and a BSS to which a trigger frame is sent. Specifically, when the trigger frame is sent from the same BSS as the BSS including the wireless communication terminal, the wireless communication terminal may reduce the OBO counter value based on the trigger frame. In another specific embodiment, when the trigger frame triggers the transmission of a plurality of wireless communication terminals included in one or more BSSs among a plurality of BSSs corresponding to a multi-BSSID set, the wireless communication terminal included in the same BSS as at least one of the plurality of triggered wireless communication terminals may reduce the OBO counter value based on the trigger frame. In another specific embodiment, an unassociated wireless communication terminal may reduce the OBO counter value based on the trigger frame regardless of the BSS that sends the trigger frame. At this time, when there is a recipient of a frame to be sent by the unassociated wireless communication terminal, the unassociated wireless communication terminal may reduce the OBO counter value based on only the trigger frame sent from the BSS including the corresponding recipient. For example, when the unassociated wireless communication terminal is to send an association request frame, the unassociated wireless communication terminal may reduce the OBO counter value based on only the trigger frame sent from the BSS to which the recipient of the association request frame belongs. At this time, when the unassociated wireless communication terminal is to send a probe request frame, the unassociated wireless communication terminal may reduce the OBO counter value based on only the trigger frame regardless of the BSS that sends the trigger frame.

[0162] Figure 20 (a) shows the association relationship between a first access point AP 1, a second access point AP 2, a first station STA 1, and an x-th station STA x. The first access point AP 1 and the first station STA 1 are associated, and the x-th station STA x is not associated with any access point. Figure 20(b) shows the operation in which the first station STA 1 and the x-th station STA x perform random access using OFDMA. At this time, the first station STA 1 obtains 10 as the OBO counter value. The x-th station STA x obtains 14 as the OBO counter value. The first access point AP1 sends a trigger frame TF-R signaling that three RUs are allowed to be randomly accessed. At this time, since the first station STA 1 is associated with the first access point AP 1, the OBO counter is decreased by 3 based on the trigger frame TF-R and the OBO counter is set to 7. In addition, since the x-th station STA x is not associated with any access point, the OBO counter is decreased by 3 and the OBO counter is set to 11. The second access point AP 2 sends a trigger frame TF-R signaling that five RUs are allowed to randomly access. At this time, since the trigger frame is sent in a BSS other than the BSS including the first station STA 1, the first station STA 1 does not decrease the OBO counter value. Since the x-th station STA x is not associated with any access point, the OBO counter is decreased by 5 and the OBO counter is set to 6. At this time, the station x STA x can decrease the OBO counter value according to the frame to be sent by the station x STA. Specifically, when the station x STA x sends a probe request frame, the station x STA x can decrease the OBO counter regardless of the access point that sends the trigger frame. In addition, when the station x STA x sends an association request frame, the station x STA x can decrease the OBO counter only when the access point that sends the trigger frame is the access point to receive the association request frame.

[0163] Figure 21 Shows the operation of a wireless communication terminal according to an embodiment of the present invention.

[0164] The wireless communication terminal receives the frame (S2101). Specifically, the wireless communication terminal can receive a PPDU and obtain a frame from the PPDU.

[0165] The wireless communication terminal accesses a channel according to whether the received frame is an in-BSS frame or an inter-BSS frame (S2103). When using a multi-BSSID set, the wireless communication terminal may regard multiple BSSs identified by each of multiple BSSIDs included in the same multi-BSSID set as the same BSS. When using a multi-BSSID set, the wireless communication terminal may regard multiple BSSs identified by each of multiple BSSIDs included in the same multi-BSSID set as the same BSS. For example, the BSS of the wireless communication terminal may be the first BSS and the first BSS may correspond to a multi-BSS identifier (BSSID) set. At this time, the wireless communication terminal may regard a frame sent from a second BSS corresponding to the corresponding multiple BSSIDs as an in-BSS frame. A multi-BSSID set is a set of BSSIDs of multiple BSSs classified into one group. Specifically, multiple BSSs corresponding to the multi-BSSID set may use the same channel. In addition, multiple BSSs corresponding to the multi-BSSID set may be operated by one wireless communication terminal.

[0166] The wireless communication terminal may determine whether the received frame is an in-BSS frame or an inter-BSS frame based on the BSS color. Therefore, multiple BSSs corresponding to the same multi-BSSID set may all have the same BSS color value. At this time, the BSS color may be information for identifying the BSS signaled through the physical layer of the frame. Specifically, the BSS color value of multiple BSSs corresponding to the multi-BSSID set may be set in the same manner as in the embodiments described with reference to Figures 9 to 12 By this, the wireless communication terminal may process multiple BSSs identified by multiple BSSIDs included in the multiple BSSIDs as the same BSS.

[0167] In another specific embodiment, each of multiple BSSs corresponding to the multi-BSSID set may have a different BSS color value. At this time, the wireless communication terminal may obtain the BSS color values of multiple BSSs corresponding to the multi-BSSID set through various signaling methods. At this time, the signaling method may be the same as the signaling method of the embodiments described with reference to Figure 8 and Figure 13 described.

[0168] A wireless communication terminal may determine whether a received frame is an in-BSS frame or an inter-BSS frame based on the MAC address signaled in the MAC layer. At this time, the wireless communication terminal may determine whether the received frame is an inter-BSS frame or an in-BSS frame based on the address field of the received frame. Specifically, the wireless communication terminal may determine whether the received frame is an in-BSS frame or an inter-BSS frame based on the MAC address signaled in the MAC layer of the received frame and the plurality of BSSIDs included in the multi-BSSID set. In a specific embodiment, when the MAC address signaled in the MAC layer of the frame received by the wireless communication terminal matches one of the plurality of BSSIDs included in the multi-BSSID set, the wireless communication terminal may determine the received frame as an in-BSS frame. For example, when the transmitter address or the receiver address signaled in the MAC layer of the frame received by the wireless communication terminal corresponds to another BSSID of the multi-BSSID set, the wireless communication terminal may determine the received frame as an in-BSS frame. At this time, the MAC address signaled in the MAC layer may be signaled with an individual / group bit indicating whether the MAC address is a group MAC address. In this case, the wireless communication terminal may determine whether the MAC address signaled in the MAC layer except for the individual / group bit matches the MAC address of the access point operating the BSS including the wireless communication terminal or the BSSID of the BSS including the wireless communication terminal. In addition, when the MAC address signaled in the MAC layer of the frame received by the wireless communication terminal does not match any of the plurality of BSSIDs included in the multi-BSSID set (including the BSSID of the BSS including the wireless communication terminal), the wireless communication terminal may determine the received frame as an inter-BSS frame.

[0169] When the received frame is an in-BSS frame and the receiver of the received frame is not a wireless communication terminal, the wireless communication terminal can enter the power saving state. At this time, when the MAC address signaled at the MAC layer of the frame received by the wireless communication terminal matches any one of the multiple BSSIDs included in the multi-BSSID set and the receiver of the received frame is not a wireless communication terminal, the wireless communication terminal can enter the power saving state. Specifically, when the receiver address or the transmitter address of the frame received by the wireless communication terminal is any one of the multiple BSSIDs included in the multi-BSSID set and the receiver address of the received frame is not the MAC address of the wireless communication terminal, the wireless communication terminal can enter the power saving state. At this time, the wireless communication terminal can maintain the power saving state until the end of the duration of the PPDU including the received frame. When the wireless communication terminal determines whether to enter the power saving state, the wireless communication terminal can determine whether the receiver address is an address indicating multiple wireless communication terminals including the wireless communication terminal. The address indicating multiple wireless communication terminals including the wireless communication terminal can be at least one of the above-mentioned broadcast address, multicast address, and group address. Specifically, the wireless communication terminal can operate in the same manner as the embodiments described with reference to Figure 10 and Figure 14 and Figure 15 The described embodiments are the same.

[0170] In addition, the wireless communication terminal can apply different CCA thresholds according to whether the received frame is an inter-BSS frame or an in-BSS frame. For the sake of convenience of description, the BSS corresponding to the multi-BSSID set corresponding to the first BSS is referred to as the second BSS, and the BSS not corresponding to the multi-BSSID set corresponding to the first BSS is referred to as the third BSS. When the frame received by the wireless communication terminal is sent from the second BSS, the wireless communication terminal can apply the general CCA level rather than the OBSS CCA level as the CCA threshold. When the frame received by the wireless communication terminal is sent from the third BSS, the wireless communication terminal can apply the OBSS CCA level as the CCA threshold. In another specific embodiment, when the frame received by the wireless communication terminal is sent from the second BSS, the wireless communication terminal can not access the corresponding channel regardless of the received signal strength. Specifically, the wireless communication terminal can operate in the same manner as the embodiments described with reference to Figure 8 , Figure 11 and Figure 12 The described embodiments are the same.

[0171] In addition, the wireless communication terminal may change the NAV setting according to whether the received frame is an in-BSS frame or an inter-BSS frame. Specifically, the wireless communication terminal may separately set the NAV for in-BSS frames and the NAV for inter-BSS frames. At this time, when the wireless communication terminal receives an in-BSS frame, the wireless communication terminal may set or update the NAV for in-BSS frames based on the received in-BSS frame. In addition, when the wireless communication terminal receives an inter-BSS frame, the wireless communication terminal may set or update the NAV for inter-BSS frames based on the received inter-BSS frame. For convenience of explanation, the BSS corresponding to the multi-BSSID set corresponding to the first BSS is referred to as the second BSS, and the BSS not corresponding to the multi-BSSID set corresponding to the first BSS is referred to as the third BSS. When the wireless communication terminal receives a frame sent from the second BSS, the wireless communication terminal may set or update the NAV for in-BSS frames based on the frame sent from the second BSS. When the wireless communication terminal receives a frame sent from the second BSS, the wireless communication terminal may set or update the NAV for in-BSS frames based on the frame sent from the second BSS. In a specific embodiment, when the wireless communication terminal receives a CF-END frame from an OBSS, the wireless communication terminal may not reset the NAV for in-BSS frames. Therefore, when the wireless communication terminal receives a CF-END frame sent from the second BSS identified by the second BSSID, the wireless communication terminal may reset the NAV for in-BSS frames and maintain the NAV for inter-BSS frames as before. When the wireless communication terminal receives a CF-END frame sent from the third BSS, the wireless communication terminal may reset the NAV for inter-BSS frames and maintain the NAV for in-BSS frames as before.

[0172] Although the present invention has been described by using wireless LAN communication as an example, the present invention is not limited thereto and may be applied to other communication systems such as cellular communication. Additionally, although the methods, devices, and systems of the present invention are described together with specific embodiments of the present invention, some or all of the components or operations of the present invention may be implemented using a computer system having a general hardware architecture.

[0173] The features, structures, and effects described in the above embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. In addition, those skilled in the art may combine or modify the features, structures, and effects shown in each embodiment in other embodiments. Therefore, it should be understood that the content related to such combinations and modifications is included in the scope of the present invention.

[0174] Although the present invention is mainly described based on the above embodiments, it is not limited thereto. However, those skilled in the art will understand that various changes and modifications can be made without departing from the spirit and scope of the present invention. For example, each component specifically shown in the embodiments can be modified and implemented. It should be understood that the differences related to such modifications and applications are included within the scope of the present invention defined in the appended claims.

Claims

1. A wireless communication terminal for wireless communication, the terminal comprising: a transceiver; and a processor, wherein a basic service set (BSS) of the wireless communication terminal corresponds to a set of multi - BSS identifiers (BSSIDs), wherein the set of multi - BSSIDs is a set of BSSIDs of each of a plurality of BSSs classified into one group, wherein the processor is configured to: detect a first frame through the transceiver, when a transmitter address (TA) or a receiver address (RA) signaled in a media access control (MAC) header of the first frame matches any one of a plurality of BSSIDs included in the set of multi - BSSIDs, determine the first frame as an in - BSS frame, sense a signal strength of the first frame, determine whether to access a channel while transmitting the first frame according to a comparison of the signal strength with a threshold value, wherein the value of the threshold is determined based on determining the first frame as the in - BSS frame, and transmit a second frame based on a determination of whether to access the channel, wherein values of BSS colors corresponding to the plurality of BSSs are the same as each other, and wherein the BSS color is information identifying a BSS signaled in a physical layer signaling field of a physical layer convergence protocol data unit (PPDU) including the first frame.

2. The wireless communication terminal according to claim 1, wherein The processor is configured to: apply a first threshold to determine whether to access the channel when the first frame is the in - BSS frame, and apply a second threshold to determine whether to access the channel when the first frame is an inter - BSS frame, wherein the second threshold is determined within an overlapping BSS (OBSS) level range, wherein the OBSS level range includes a value equal to or greater than the first threshold.

3. The wireless communication terminal according to claim 1, wherein, The processor is configured to enter a power - saving state when the first frame is the in - BSS frame and the RA of the first frame does not indicate the wireless communication terminal.

4. The wireless communication terminal according to claim 3, wherein, The processor is configured to maintain the power - saving state during a duration of the PPDU including the first frame.

5. The wireless communication terminal according to claim 1, wherein, The processor is configured to separately set a network allocation vector (NAV) for the in - BSS frame and a NAV for the inter - BSS frame, and access the channel based on the NAV for the in - BSS frame and the NAV for the inter - BSS frame.

6. The wireless communication terminal according to claim 5, wherein, When the TA or the RA in the MAC header of the first frame matches any one of the plurality of BSSIDs included in the set of multi - BSSIDs, the processor is configured to set the NAV for the in - BSS frame based on the first frame.

7. An operating method of a wireless communication terminal for wireless communication, the method comprising: detecting a first frame; When the transmitter address (TA) or receiver address (RA) signaled in the media access control (MAC) header of the first frame matches any one of the multiple basic service set identifiers (BSSIDs) included in the BSS corresponding set of the wireless communication terminal, determine the first frame as an in-BSS frame, where the multi-BSSID set is a set of BSSIDs of each of the multiple BSSs classified into one group; Sense the signal strength of the first frame, Determine whether to access the channel while transmitting the first frame according to comparing the signal strength with a threshold value, where the value of the threshold is determined based on determining the first frame as the in-BSS frame, and Perform transmission based on determining whether to access the channel, where the values of the BSS colors corresponding to the multiple BSSs are the same as each other, and where the BSS color is information identifying the BSS signaled in the physical layer signaling field of the physical layer convergence protocol data unit (PPDU) including the first frame.

8. The method according to claim 7, the method further comprising: When the first frame is the in-BSS frame, apply a first threshold to determine whether to access the channel, and When the first frame is an inter-BSS frame, apply a second threshold to determine whether to access the channel, where the second threshold is determined within an OBSS level range, where the OBSS level range is equal to or greater than the first threshold.

9. The method according to claim 7, wherein the method further comprises: Enter a power saving state when the first frame is the in-BSS frame and the RA of the first frame does not indicate the wireless communication terminal.

10. The method according to claim 9, wherein, Entering the power saving state includes: maintaining the power saving state during the duration of the PPDU including the first frame.

11. The method according to claim 7, wherein, The method further comprises: separately setting a network allocation vector (NAV) for the in-BSS frame and a NAV for the inter-BSS frame, and accessing the channel based on the NAV for the in-BSS frame and the NAV for the inter-BSS frame.

12. The method according to claim 11, wherein Separately setting the NAV includes: when the TA or the RA signaled in the MAC header of the first frame matches any one of the multiple BSSIDs included in the multi-BSSID set, setting the NAV for the in-BSS frame based on the first frame.

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