Station device and access point device

Abstract

In the present invention, a wireless communication device supports enhanced multi-link single radio (EMLSR). One or more user info fields are included in an MU-RTS trigger frame. At least one of the one or more user info fields is allocated to one non-AP MLD. The index of an RU of a secondary channel is set in an RU allocation subfield of the user info field allocated to the non-AP MLD. The values of AID12 subfields of the user info fields in which the index of the RU of the secondary channel is set are the same. Frame exchange in the secondary channel is performed by transmitting the MU-RTS trigger frame as an initial control frame.

Description

Station equipment, access point equipment

[0001] The present invention relates to a station device and an access point device. This application claims priority to Japanese Patent Application No. 2024-131862, filed on August 8, 2024, the contents of which are incorporated herein by reference.

[0002] The Institute of Electrical and Electronics Engineers Inc. (IEEE) is currently standardizing IEEE 802.11be, a wireless LAN (Local Area Network) standard that will achieve even faster speeds than the IEEE 802.11 standard, and wireless LAN devices that comply with the draft specification are now available on the market. Currently, standardization activities for IEEE 802.11bn, the successor to IEEE 802.11be, have begun. The main theme of the IEEE 802.11bn standardization is the realization of Ultra-High Reliability (UHR).

[0003] Wireless LANs can transmit and receive frames using unlicensed bands, which allow wireless communication without requiring permission (license) from a country or region. For home and other personal use, wireless Internet access from within a home has become possible by incorporating wireless LAN access point functionality into a line termination device for connecting to a wide area network (WAN) line, such as the Internet, or by connecting a wireless LAN access point device (also referred to as an access point device) to the line termination device. In other words, wireless LAN station devices (also referred to as station devices), such as smartphones and personal computers, can connect to a wireless LAN access point device to access the Internet. When wireless LANs were first introduced to homes, there was often only one wireless LAN access point device per home. However, in recent years, multiple wireless LAN access point devices have been introduced to expand the coverage of the wireless LAN usage area within the home.

[0004] In the IEEE 802.11 series specifications, a wireless communication device in a wireless LAN system is called a STA (STAtion), a STA that connects to multiple other STAs and provides network services is called an AP STA (Access Point STA), and a STA that connects to an AP STA and receives network services is called a non-AP STA. Hereinafter, an AP STA is also called an access point (AP), an access point device, or a base station device, and a non-AP STA is also called a terminal, a user terminal, a terminal device, or a user terminal device.

[0005] Regarding wireless LANs, the United States allows the use of the 6 GHz band (5.925 to 7.125 GHz) as an unlicensed band, while Europe and Japan allow the use of the lower frequencies of the 6 GHz band (5.925 to 6.425 GHz), with consideration underway for the upper frequencies (6.425 to 7.125 GHz). Similar considerations are also underway in other countries around the world. Due to these trends, it is expected that wireless LANs will be able to use the 6 GHz band in addition to the 2.4 GHz and 5 GHz bands. To accommodate the expansion of applicable frequencies, the Wi-Fi Alliance has formulated Wi-Fi 6E (registered trademark), an extension of Wi-Fi 6, which will use the 6 GHz band.

[0006] The 6 GHz band is a frequency band from approximately 5.925 to 7.125 GHz, and a total of approximately 1.2 GHz of bandwidth will be newly available, which means an increase of 14 channels in terms of 80 MHz width channels and 7 channels in terms of 160 MHz width channels. Because abundant frequency resources can be used, the maximum channel bandwidth available for a single wireless LAN communication system (equivalent to BSS, described below) is expanded from 160 MHz in IEEE 802.11ax to 320 MHz, double the bandwidth in IEEE 802.11be.

[0007] While the 2.4 GHz band offers a relatively wide coverage (range of communication), it is subject to significant interference between communication devices and has a relatively narrow available bandwidth. While the 5 GHz and 6 GHz bands offer wide communication bandwidths, they lack wide coverage. Therefore, to realize various services and applications over a wireless LAN, it is desirable to bundle or switch between frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc., or channels or subchannels included in each frequency band) depending on the use case. However, devices using conventional wireless LAN communication standards were unable to bundle and use different frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.) used for communication. Furthermore, to switch frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.), it was necessary to disconnect from the current frequency band and reconnect to another frequency band.

[0008] Therefore, IEEE 802.11be specifies Multi-Link Operation (MLO), which enables a communication device to use multiple frequency bands and connect via multiple links (multi-link). One example is simultaneous operation of three link connections: a 2.4 GHz band connection, a 5 GHz band connection, and a 6 GHz band connection. Of course, the combinations of frequency bands, channels, and subchannels, and the number of simultaneous connections, are not limited to these combinations and are various. From the perspective of frequency bands, millimeter waves (45 GHz band, 60 GHz band, etc.) may also be used as one of the links constituting Multi-Link in the future. MLO allows a communication device to maintain multiple link connections with different wireless resources and communication settings. That is, by using MLO, a communication device can simultaneously maintain link connections in different frequency bands. Not only can it transmit and receive frames using multiple links simultaneously, but it can also switch the link connection for transmitting and receiving frames (change the frequency band) without performing a reconnection operation.

[0009] Regarding MLO, IEEE 802.11be specifies Enhanced Multi-Link Single Radio (EMLSR). Operation in EMLSR mode (EMLSR operation) allows a Non-AP multi-link device (Non-AP MLD) with multiple active receive chains to listen for an Initial Control Frame (ICF) transmitted using a single spatial stream from an access point (AP) belonging to the Access Point Multi-Link Device (AP MLD) in the set of enabled links, and to exchange frames on the link on which the ICF is received. The ICF is transmitted in a non-high throughput duplicate physical layer protocol data unit (non-HT duplicate PPDU).

[0010] In the standardization of IEEE 802.11bn, discussions on Non-Primary Channel Access (NPCA) are underway (see Non-Patent Document 1). In conventional technologies, the maximum operating bandwidth is specified to be wider as the generation becomes newer, such as 160 MHz for IEEE 802.11ax and 320 MHz for IEEE 802.11be. The operating bandwidth is divided into multiple 20 MHz subchannels for management. NPCA is a technology in which, when a 20 MHz primary channel is busy due to a network allocation vector (NAV) being set to a basic service set (BSS) frame transmission / reception, for example, some or all of the wireless communication devices belonging to the basic service set (BSS) perform a channel transition (channel switch, channel change) to the NPCA primary channel, and if a transmission opportunity is available at the channel transition destination, the wireless communication devices can transmit and receive frames. Here, the NPCA primary channel is a sub-channel other than the primary channel that is included in the operation bandwidth (operation channel) of the wireless communication system, and is generally a 20 MHz sub-channel, but may be a sub-channel with a bandwidth greater than that.

[0011] Conventionally, it was necessary to designate one 20 MHz subchannel as a primary channel, first acquire a transmission opportunity (transmission right) on the primary channel, and then proceed to acquire a transmission opportunity on a 20 MHz subchannel other than the primary channel. Therefore, if a transmission opportunity on the primary channel could not be acquired, a transmission opportunity could not be acquired even if multiple 20 MHz subchannels other than the primary channel were idle (unused). For example, if a transmission right on the 20 MHz primary channel could not be acquired, the remaining 300 MHz bandwidth could not be used even if it was idle. The mechanism for acquiring transmission opportunities based on the primary channel is a remnant of the technological development of wireless LANs, which maintained backward compatibility. Wireless communication technologies that use the same frequency band as wireless LANs include LAA (Licensed Assisted Access), but there is no channel access restriction based on the primary channel like wireless LANs, and wireless LAN technology is at a disadvantage in terms of acquiring transmission opportunities. Furthermore, similar to link switching in EMLSR, a hardware delay equivalent to a channel switch delay occurs in order to transition to a non-primary channel, the magnitude of which differs depending on the wireless communication device.

[0012] In IEEE802.11bn, a new channel access method is being considered that enables the use of multiple 20 MHz sub-channels other than the primary channel even when a transmission opportunity cannot be obtained on the 20 MHz primary channel (Non-Patent Documents 1 and 2). However, assuming EMLSR in IEEE802.11be, it is necessary to take into account a multi-stage process, such as moving from the primary channel to a channel other than the primary channel (non-primary channel) after going through a frame exchange sequence required for link switching and the processing time that occurs when switching the link, which poses a challenge in achieving low-latency communication.

[0013] IEEE 802.11-24 / 0495-00-00bn, May.2024IEEE 802.11-24 / 0591-01-00bn, June.2024

[0014] In wireless communication devices, EMLSR operation requires consideration of both processes of link switching and migration from a primary channel to a non-primary channel, which poses a challenge in achieving low-latency communications.

[0015] A station device and an access point device according to one aspect of the present invention for solving the above-mentioned problems are as follows.

[0016] (1) That is, a wireless communication device according to one embodiment of the present invention is an access point device, the access point device being an access point multi-link device, comprising a transmitter and a controller, the controller supporting Enhanced Multi-Link Single Radio (EMLSR), the controller further including one or more User Info fields in an MU-RTS trigger frame, assigning at least one of the one or more User Info fields to one Non-AP multi-link device, setting an index of an RU of a secondary channel in an RU allocation subfield of the User Info field assigned to the Non-AP multi-link device, the values ​​of the AID12 subfields of the User Info fields in which the index of the RU of the secondary channel is set are the same, and the transmitter further transmits the MU-RTS trigger frame as an initial control frame.

[0017] (2) Also, a wireless communication device according to one embodiment of the present invention is the access point device, wherein the control unit includes a Basic Multi-Link element in a beacon or a probe response frame, includes first control information in the Basic Multi-Link element, the first control information includes information indicating support for EMLSR Secondary Channel Access, and the transmission unit transmits the beacon or the probe response frame.

[0018] (3) Also, a wireless communication device according to one aspect of the present invention is a station device, the station device being a Non-AP multilink device, comprising a transmitter, a controller, and a receiver, the controller supporting Enhanced Multi-Link Single Radio (EMLSR) and including first control information in an Enhanced Multi-Link (EML) Control field of an Enhanced Multi-Link (EML) Operating Mode Notification frame, the first control information indicating that Secondary Channel Access Mode is enabled in EMLSR, the transmitter transmits the Enhanced Multi-Link (EML) Operating Mode Notification frame, the receiver receives an MU-RTS trigger frame as an initial control frame, and the controller, when a value of an AID12 subfield of one or more User Info fields included in the MU-RTS trigger frame is an AID assigned to the Non-AP multilink device, The transmitter selects at least one index of an RU on a secondary channel from the allocation subfield, and further transmits a CTS frame on the channel indicated by the selected index in response to receiving the MU-RTS trigger frame.

[0019] (4) Furthermore, a wireless communication device according to one aspect of the present invention is the station device, and the association request frame includes, as capability information, information indicating that Secondary Channel Access Mode is enabled in EMLSR.

[0020] According to the station device and access point device of the present invention, EMLSR Secondary Channel (SC) operation can simultaneously perform both the link switching and the movement from the primary channel to the secondary channel processes required for EMLSR operation, which is expected to realize low-latency communication.

[0021] FIG. 1 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. FIG. 1 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of an architecture of a wireless communication device according to an embodiment of the present invention. FIG. 3 is a schematic diagram illustrating an example of division of a wireless medium according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of a configuration of a communication system according to an embodiment of the present invention. FIG. 5 is a block diagram illustrating an example of a configuration of a wireless communication device according to an embodiment of the present invention. FIG. 6 is a block diagram illustrating an example of a configuration of a wireless communication device according to an embodiment of the present invention. FIG. 7 is a block diagram illustrating an example of a configuration of a wireless communication device according to an embodiment of the present invention. FIG. 8 is a diagram illustrating an example of a configuration of a frame sequence according to an embodiment of the present invention. FIG. 9 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. FIG. 10 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. FIG. 11 is a diagram illustrating an example of a frame sequence according to an embodiment of the present invention.

[0022] The wireless communication system in this embodiment includes an access point device (also referred to as an AP, AP STA, or base station device) and multiple terminal devices (also referred to as non-AP STA or station devices). The wireless communication system and network configured with the access point device and the terminal devices connected to the access point device are referred to as a BSS (Basic Service Set, management range). Hereinafter, when simply referring to an STA or wireless communication device without limitation, it refers to both the access point device and the terminal devices.

[0023] The access point device and station devices within the BSS communicate based on CSMA / CA (Carrier sense multiple access with collision avoidance). This embodiment focuses on infrastructure mode, in which an access point device communicates with multiple station devices. However, the method of this embodiment can also be implemented in ad hoc mode, in which station devices communicate directly with each other. In ad hoc mode, station devices form a BSS in place of access point devices. A BSS in ad hoc mode is also referred to as an IBSS (Independent Basic Service Set). Hereinafter, station devices forming an IBSS in ad hoc mode can also be considered as access point devices. The method of this embodiment can also be implemented in Wi-Fi Direct (registered trademark), in which station devices communicate directly with each other. In Wi-Fi Direct, station devices form groups in place of access point devices. Hereinafter, a group owner station device forming a group in Wi-Fi Direct can also be considered as an access point device.

[0024] FIG. 3 shows an architecture diagram of a wireless communication device. The MAC layer corresponds to a layer above the PHY layer. The MAC layer may also be referred to as the upper layer, and the PHY layer as the lower layer. The PHY layer includes a management entity called a Physical Layer Management Entity (PLME), and PHY layer management functions are activated via the PLME. Similarly, the MAC layer includes a management entity called a Medium Access Control sublayer Management Entity (MLME), and MAC layer management functions are activated via the MLME.

[0025] The SME (Station Management Entity) is a layer-independent entity whose role is to collect layer-specific status information such as PHY and MAC, and to set parameter values ​​specific to the PHY and MAC layers. An interface called the MLME SAP (Service Access Point) exists between the SME and MLME, and the MAC layer and SME interact by exchanging MLME SAP Primitives via the MLME SAP. An interface called the PLME SAP exists between the SME and PLME, and the PHY layer and SME interact by exchanging PLME SAP Primitives via the PLME SAP. The MAC layer and communication layers above the MAC layer interact by exchanging MAC Service Primitives (also called MAC SAP Primitives) via the MAC SAP. The MAC layer and PHY layer interact by exchanging PHY Service Primitives (also called MAC SAP Primitives) via the PHY SAP. MLME SAP Primitive, PLME SAP Primitive, MAC Service Primitive, PHY Service Primitive, etc. are collectively referred to as Primitive.

[0026] In the IEEE 802.11 system, each wireless communication device can transmit frames of multiple frame types that share a common frame format. The frames are defined in the physical (PHY) layer, medium access control (MAC) layer, and logical link control (LLC) layer.

[0027] A PHY layer frame is called a physical protocol data unit (PPDU, PHY layer frame, radio frame, or frame). A PPDU consists of a physical layer header (PHY header) containing header information for signal processing at the physical layer, and a physical service data unit (PSDU, PHY layer frame), which is a data unit processed at the physical layer. A PSDU can be composed of a MAC protocol data unit (MPDU), which is a retransmission unit in the radio section, or an aggregated MPDU (A-MPDU), which aggregates multiple MAC protocol data units.

[0028] The PHY header includes reference signals such as a short training field (STF) used for signal detection and synchronization, a long training field (LTF) used to acquire channel information for data demodulation, and control signals such as a signal (SIG) containing control information for data demodulation. Depending on the corresponding standard, STF is classified into non-High throughput-STF (non-HT STF or L-STF), High throughput-STF (HT-STF), Very high throughput-STF (VHT-STF), High efficiency-STF (HE-STF), Extremely High Throughput-STF (EHT-STF), and the like. Similarly, LTF and SIG are classified into L-LTF, HT-LTF, VHT-LTF, HE-LTF, L-SIG, HT-SIG, VHT-SIG, HE-SIG, and EHT-SIG. VHT-SIG is further classified into VHT-SIG-A1, VHT-SIG-A2, and VHT-SIG-B. Similarly, HE-SIG is classified into HE-SIG-A1 to HE-SIG-A4 and HE-SIG-B. In addition, a Universal SIGNAL (U-SIG) field containing additional control information may be included, assuming technology updates within the same standard.

[0029] Furthermore, the PHY header can include information for identifying the BSS that is the sender of the frame (hereinafter also referred to as BSS identification information). The information for identifying the BSS can be, for example, the SSID (Service Set Identifier) ​​of the BSS or the MAC address of the access point device of the BSS. The information for identifying the BSS can also be a value unique to the BSS (for example, a BSS Color) other than the SSID or MAC address.

[0030] The PPDU is modulated according to the corresponding standard, for example, into a Direct Sequence Spread Spectrum (DSSS) signal for the IEEE 802.11b standard, or into an Orthogonal Frequency Division Multiplexing (OFDM) signal for the IEEE 802.11a standard and its successors (IEEE 802.11g / n / ac / ax / be / bn, etc.).

[0031] The wireless communication device has either a function for transmitting a PPDU or a function for receiving a PPDU, or both. Fig. 1 is a diagram showing an example of the configuration of a PPDU transmitted by a wireless communication device. A PPDU conforming to the IEEE 802.11a / b / g standard is configured to include an L-STF, an L-LTF, an L-SIG, and a Data frame (MAC frame, MAC frame, payload, data portion, data, information bits, etc.). An HT PPDU (High throughput PPDU) conforming to the IEEE 802.11n standard is configured to include an L-STF, an L-LTF, an L-SIG, an HT-SIG, an HT-STF, an HT-LTF, and a Data frame. The VHT PPDU (Very High Throughput PPDU) conforming to the IEEE 802.11ac standard is a configuration including some or all of the L-STF, L-LTF, L-SIG, VHT-SIG-A, VHT-STF, VHT-LTF, VHT-SIG-B, and MAC frames. The HE PPDU (High Efficiency PPDU) conforming to the IEEE 802.11ax standard is a configuration including some or all of the RL-SIG, HE-SIG-A, HE-STF, HE-LTF, HE-SIG-B, and Data frames, which are L-STF, L-LTF, L-SIG, and RL-SIG, which are repeated over time. The EHT PPDU (Extremely High Throughput PPDU) standardized by IEEE 802.11be is a structure that includes some or all of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF, and Data frames.

[0032] Figure 2 shows an example of an MPDU structure. An MPDU (also called a MAC frame) consists of a MAC header containing header information for signal processing at the MAC layer, a MAC service data unit (MSDU) or frame body, which is a data unit processed at the MAC layer, and a frame check sequence (FCS) that checks for frame errors. The MAC header includes a Frame Control field, a Duration / ID field, an Address 1 field, an Address 2 field, an Address 3 field, a Sequence Control field, an Address 4 field, a QoS Control field, an HT Control field, a Frame Body field, and an FCS field. The Frame Control field identifies the frame type (such as a management frame, control frame, data frame, or extension frame). The Duration / ID field (which may simply be called the Duration field) contains a value corresponding to the length of the transmission opportunity. The frame's transmitting address (TA: Transmitter Address) and receiving address (RA: Receiver Address) can be determined from information in the Address 1 field, Address 2 field, Address 3 field, Address 4 field, etc.

[0033] 1 are structures commonly used in the IEEE 802.11 standard (hereinafter, L-STF, L-LTF, and L-SIG are also collectively referred to as the L-header). For example, a wireless communication device that complies with the IEEE 802.11a / b / g standard can properly receive an L-header in a PPDU that complies with the IEEE 802.11n / ac standard. A wireless communication device that complies with the IEEE 802.11a / b / g standard can receive a PPDU that complies with the IEEE 802.11n / ac standard, treating it as a PPDU that complies with the IEEE 802.11a / b / g standard.

[0034] However, wireless communication devices that comply with the IEEE 802.11a / b / g standards cannot demodulate the PPDU that follows the L-header and complies with the IEEE 802.11n / ac standards, and therefore cannot demodulate the transmitter address (TA), receiver address (RA), and information about the Duration field used to set the network allocation vector (NAV) contained in the MAC header.

[0035] IEEE 802.11 specifies a method of inserting Duration information into L-SIG as a method for wireless communication devices conforming to the IEEE 802.11a / b / g standards to appropriately set NAV (or perform reception for a predetermined period of time). Information about the transmission rate in L-SIG (RATE field, L-RATE field, L-RATE, L_DATARATE, L_DATARATE field) and information about the transmission period (LENGTH field, L-LENGTH field, L-LENGTH field) are used by wireless communication devices conforming to the IEEE 802.11a / b / g standards to appropriately set NAV.

[0036] Next, a method for identifying a BSS from a frame received by a wireless communication device will be described. In order for a wireless communication device to identify a BSS from a frame received, it is preferable for the wireless communication device transmitting a PPDU to insert information for identifying the BSS (BSS Color, BSS identification information, a value unique to the BSS) into the PPDU. Information indicating the BSS Color can be included in the HE-SIG-A.

[0037] The wireless communication device can transmit the L-SIG multiple times (L-SIG Repetition). For example, the receiving wireless communication device receives the L-SIG transmitted multiple times using MRC (Maximum Ratio Combining), thereby improving the demodulation accuracy of the L-SIG. Furthermore, when the wireless communication device has correctly received the L-SIG using MRC, it can interpret the PPDU including the L-SIG as a PPDU conforming to the IEEE 802.11ax standard.

[0038] Even during the operation of receiving a PPDU, the wireless communication device can perform an operation of receiving a part of a PPDU other than the PPDU (for example, a preamble, L-STF, L-LTF, PHY header, etc., as defined by IEEE 802.11) (also referred to as a dual reception operation). When the wireless communication device detects a part of a PPDU other than the PPDU during the operation of receiving a PPDU, it can update some or all of the destination address, source address, and information related to the PPDU or DATA period.

[0039] MAC layer frame types are broadly classified into three types: management frames (also called management frames or wireless management frames) that manage the connection status between wireless communication devices; control frames (also called control frames or wireless control frames) that manage the communication status between wireless communication devices; and data frames that contain actual transmission data. Each type is further classified into multiple subframe types. Control frames include acknowledgement (Ack) frames, request to send (RTS) frames, and clear to send (CTS) frames. Management frames include beacon frames, probe request frames, probe response frames, authentication frames, association request frames, association response frames, and deauthentication frames. Data frames include data frames and polling (QoS CF-poll) frames. Each wireless communication device can determine the frame type and subframe type of a received frame by reading the contents of the Frame Control field included in the MAC header.

[0040] An MMPDU (MAC Management Protocol Data Unit) is a data unit exchanged between MAC entities, and may include a Mesh Control field and a Management MIC (Message Integrity Code) element (MME). A MAC frame is formed by concatenating at least a MAC header, an MMPDU (stored in the frame body portion in FIG. 2 ), and an inspection portion, and is called a management frame.

[0041] The Ack may include a Block Ack, which can be used to notify completion of reception of multiple MPDUs.

[0042] A beacon frame includes a beacon interval, a field describing the SSID, an information element, and the like. An access point device can periodically broadcast a beacon frame within a BSS, and a station device can learn about the presence and capability information of access point devices around the station device by receiving the beacon frame. The process by which a station device learns about an access point device based on a beacon frame broadcast by an access point device is called passive scanning. On the other hand, the process by which a station device searches for an access point device by broadcasting a probe request frame within a BSS is called active scanning. An access point device can transmit a probe response frame in response to the probe request frame, and the contents of the probe response frame are the same as those of a beacon frame.

[0043] After recognizing an access point device, a station device performs a connection process with the access point device. The connection process is classified into an authentication procedure and an association procedure. The station device transmits an authentication frame (authentication request) to the access point device with which it wishes to connect. Upon receiving the authentication frame, the access point device transmits an authentication frame (authentication response) to the station device, which includes a status code indicating whether the station device has been authenticated. By reading the status code written in the authentication frame, the station device can determine whether its own wireless communication device has been authorized by the access point device. Note that the access point device and station device can exchange authentication frames multiple times.

[0044] Following the authentication procedure, the station device transmits a connection request frame to the access point device to perform a connection procedure. Upon receiving the connection request frame, the access point device determines whether to permit the station device to connect and transmits a connection response frame to notify the result. The connection response frame contains a status code indicating whether the connection process is successful, as well as an association identifier (AID) for identifying the station device. The access point device can identify and manage multiple station devices by setting different AIDs for each station device to which it has issued a connection permission.

[0045] After the connection process is completed, the access point device and station device actually transmit and receive frames (also called frame exchange). The IEEE 802.11 system defines a distributed coordination function (DCF), a point coordination function (PCF), and their extended functions (enhanced distributed channel access (EDCA), hybrid coordination function (HCF), etc.). The following describes an example in which an access point device transmits a frame to a station device using DCF.

[0046] In DCF, access point devices and station devices perform carrier sense (CS) to check the usage status of wireless channels around the wireless communication device before transmitting a frame. For example, the following description assumes that the wireless communication device (transmitting station) that plans to transmit a frame is an access point device, but the same applies when the transmitting station is a station device. If the access point device receives a signal higher than a predetermined clear channel assessment level (CCA level) on the wireless channel, it postpones transmitting the frame on the wireless channel. Hereinafter, a state in which a signal higher than the CCA level is detected on the wireless channel is referred to as a busy state, and a state in which a signal higher than the CCA level is not detected is referred to as an idle state. In this way, CS performed by each wireless communication device based on the power of the signal actually received (received power level) is referred to as physical carrier sense (physical CS). The CCA level is also referred to as the carrier sense level (CS level) or the CCA threshold (CCAT). When the access point device and station device detect a signal of CCA level or higher, they begin to demodulate at least the PHY layer signal.

[0047] The access point device performs carrier sensing at an interframe space (IFS) according to the type of frame to be transmitted, and determines whether the wireless channel is busy or idle. The period during which the access point device performs carrier sensing varies depending on the frame type and subframe type of the frame to be transmitted. The IEEE 802.11 system defines multiple IFSs with different durations, including a short interframe space (SIFS) used for transmission frames assigned the highest priority, a PCF IFS (PIFS) used for transmission frames with relatively high priority, and a distributed control frame space (DCF IFS (DIFS) used for transmission frames with the lowest priority.

[0048] After waiting for the DIFS period, the access point device further waits for a random backoff time to prevent frame collisions. In the IEEE 802.11 system, the random backoff time is set within the contention window (CW). CSMA / CA assumes that a transmission frame sent by a transmitting station is received by a wireless communication device serving as a receiving station without interference from other transmitting stations. Therefore, if two transmitting stations transmit frames at the same time, the frames collide, and the receiving station cannot receive the frames correctly. Therefore, frame collisions are avoided by each transmitting station waiting for a randomly set time before starting transmission. When the access point device (corresponding to the transmitting station in this description) determines through carrier sense that the wireless channel is idle, it starts counting down its backoff counter. Only when the backoff counter reaches 0 does it acquire a transmission opportunity and can transmit a frame to the station device (corresponding to the receiving station in this description). If the access point device determines by carrier sense that the wireless channel is busy while the backoff counter is counting down, it stops counting down the backoff counter. If the wireless channel becomes idle, the access point device waits for the same period (DIFS) as the previous IFS, and then resumes counting down the remaining backoff counter.

[0049] The receiving station, a station device, receives the frame, reads the PHY header of the frame, and demodulates the received frame.The station device then reads the MAC header of the demodulated signal to determine whether the frame is addressed to its own wireless communication device.The station device can also determine the destination of the frame based on information written in the PHY header (for example, in the case of a frame equivalent to a VHT PPDU, the group identification number (GID) written in the VHT-SIG-A).

[0050] If a station device determines that a received frame is addressed to its own wireless communication device and demodulates the frame without error, it must transmit an Ack frame to the access point device, which is the transmitting station, indicating that the frame was received correctly. The Ack frame is one of the highest-priority frames that is transmitted after waiting for an SIFS period without a random backoff time. When the access point device receives the Ack frame transmitted from the station device, a frame exchange is successfully completed. Note that if the station device fails to receive a frame correctly, the station device does not transmit an Ack. Therefore, if the access point device does not receive an Ack frame from the receiving station for a certain period of time (e.g., SIFS + Ack frame length) after transmitting a frame, it can consider the frame exchange to have failed. In this way, the completion of a frame exchange in an IEEE 802.11 system is always determined by whether or not an Ack frame is received, except in special cases such as when transmitting a beacon frame or other notification signal, or when fragmentation is used to divide the transmitted data.

[0051] When a station device determines that a received frame is not addressed to its own wireless communication device, it sets a network allocation vector (NAV) based on a response corresponding to the length of the acquired transmission opportunity, which is written in the MAC header or PHY header, etc. The station device does not attempt communication during the period set in the NAV. In other words, the station device performs the same operation as when it determines that the wireless channel is busy by physical CS during the period set in the NAV, so communication control using the NAV is also called virtual carrier sense (virtual CS). The NAV can be set based on information written in the MAC header or PHY header, and in the case of a frame corresponding to an HE PPDU, the value written in the TXOP field included in the HE-SIG-A may be used. Furthermore, the NAV is also set by a request to send (RTS) frame or a clear to send (CTS) frame, which are introduced to solve the hidden terminal problem, and the value written in the Duration field included in the MAC header is used.

[0052] In contrast to DCF, in which each wireless communication device performs carrier sensing and autonomously acquires transmission opportunities, in PCF, a control station called a Point Coordinator (PC) controls the transmission opportunities of each wireless communication device within the BSS. Generally, an access point device becomes the PC and acquires the transmission right for station devices within the BSS.

[0053] The PCF communication period includes a contention-free period (CFP) and a contention period (CP). During the CP, communication is performed based on the DCF described above, and the PC controls transmission opportunities during the CFP. The access point device, which is the PC, broadcasts a beacon frame containing the CFP duration (CFP Max duration) and other information within the BSS prior to PCF communication. The beacon frame broadcast at the start of PCF transmission uses PIFS and is transmitted without waiting for the random backoff time. The station device that receives the beacon frame sets the CFP duration described in the beacon frame as its NAV. Thereafter, until the NAV elapses or a signal announcing the end of the CFP within the BSS (e.g., a data frame including CF-end) is received, the station device can acquire a transmission opportunity only when it receives a signal signaling acquisition of a transmission opportunity transmitted from the PC (e.g., a data frame including CF-poll). During the CFP period, no packet collisions occur within the same BSS, so each station device does not take the random backoff time used in DCF.

[0054] A wireless medium can be divided into multiple resource units (RUs). FIG. 4 is a schematic diagram showing an example of how a wireless medium is divided. For example, in resource division example 1, a wireless communication device can divide a frequency resource (subcarrier) of the wireless medium into nine RUs. Similarly, in resource division example 2, a wireless communication device can divide a subcarrier of the wireless medium into five RUs. Of course, the resource division example shown in FIG. 4 is merely an example, and, for example, multiple RUs can each be configured with a different number of subcarriers. Furthermore, the wireless medium divided into RUs can include not only frequency resources but also spatial resources. A wireless communication device (e.g., an access point device) can simultaneously transmit frames to multiple wireless communication devices (e.g., multiple station devices) by placing frames addressed to different station devices in each RU. The access point device can include information indicating the division status of the wireless medium (resource allocation information) in the PHY header of a frame transmitted by the wireless communication device itself as common control information. Furthermore, the access point device can include information indicating the RU in which the frame addressed to each station device is placed (resource unit assignment information) as unique control information in the PHY header of the frame transmitted by its own wireless communication device.

[0055] Furthermore, multiple wireless communication devices (e.g., multiple station devices) can simultaneously transmit frames by placing the frames in the RUs assigned to them and transmitting them. After receiving a frame (Trigger frame: TF) containing trigger information transmitted from an access point device, the multiple station devices can wait a predetermined period of time before transmitting the frame. Each station device can grasp the RU assigned to its own wireless communication device based on the information contained in the TF. Furthermore, each station device can acquire the RU by random access based on the TF.

[0056] The access point device according to this embodiment can simultaneously allocate multiple RUs to one station device. The multiple RUs can be configured with contiguous or discontinuous subcarriers. The access point device can transmit a single frame using the multiple RUs allocated to one station device, or can allocate multiple frames to different RUs for transmission. At least one of the multiple frames can be a frame containing common control information for multiple station devices transmitting resource allocation information.

[0057] One station device according to this embodiment can be assigned multiple RUs by the access point device. The station device can transmit one frame using the assigned multiple RUs. Furthermore, the station device can use the assigned multiple RUs to transmit multiple frames, each assigned to a different RU. The multiple frames can each be a frame of a different frame type. [1. First Embodiment]

[0058] The wireless communication system of this embodiment will be described using Figure 5. The wireless communication system 2-5 (also referred to as BSS 2-5) includes an access point device 1-1. Station devices 2-1, 2-2, 2-3, and 2-4 are collectively referred to as station device 2A (terminal device 2A) as station devices connected (associated) with the access point device 1-1. The access point device 1-1 and station device 2A are wirelessly connected and are capable of transmitting and receiving frames to and from each other. Hereinafter, the BSS will also be referred to as a communication area (coverage).

[0059] The wireless communication system 3-5 (also referred to as BSS 3-5) includes an access point device 1-2 and station devices 3-1, 3-2, 3-3, and 3-4. The station devices 3-1, 3-2, 3-3, and 3-4 are also collectively referred to as station device 2B (terminal device 2B) as devices connected (associated) with the access point device 1-2. The access point device 1-2 and station device 2B are wirelessly connected and are capable of transmitting and receiving wireless frames to and from each other.

[0060] 5, the access point device 1-1 is located within the coverage of the wireless communication system 3-5 of the access point device 1-2. Similarly, the access point device 1-2 is located within the coverage of the wireless communication system 2-5 of the access point device 1-1. Therefore, it is assumed that the access point devices 1-1 and 1-2 can transmit and receive wireless frames to each other.

[0061] The wireless communication device is a multi-link device (MLD) capable of multi-link communication. An access point device that supports MLD is referred to as an MLD access point device (access point multi-link device or AP MLD), and a station device that supports MLD is referred to as an MLD station device (non-access point multi-link device or Non-AP MLD). Furthermore, MLD access point devices and MLD station devices are collectively referred to as MLD wireless communication devices. Furthermore, an AP that belongs to an AP MLD is also referred to as an affiliated AP or sub-access point device, and a station device that belongs to a non-AP MLD is also referred to as a non-AP STA or sub-station device. In other words, the AP and station device according to this embodiment are multi-link devices, with the AP being an access point multi-link device and the station device being a non-AP multi-link device.

[0062] The MLD access point device 20000-1 and the MLD station device 30000-1 will be described using Figure 6. The MLD wireless communication device is composed of multiple sub-wireless communication devices corresponding to the frequency bands (or channels, or sub-channels) of each link (also referred to as a physical layer link) that constitutes a multi-link. Figure 6 shows an example in which the MLD access point device 20000-1 is composed of three sub-wireless communication devices, in this case three sub-access point devices (20000-2, 200000-3, and 20000-4), but the number of sub-access point devices may be any number greater than or equal to one. Similarly, Figure 6 shows an example in which the MLD station device 30000-1 is composed of three sub-wireless communication devices, in this case three substation devices (30000-2, 300000-3, and 30000-4), but the number of substation devices may be any number greater than or equal to one. In addition, the sub-wireless communication device (sub-access point device, sub-station device, etc.) may be configured as part of the circuitry within the wireless communication device, and may be called a sub-wireless communication unit (sub-access point unit, sub-station unit).

[0063] 6, for the sake of explanation, multiple sub-wireless communication devices are shown as logically separate blocks (squares), but they may be physically configured as a single wireless communication device. Alternatively, they may be physically configured as separate sub-wireless communication devices, in which case each sub-access point device transmits and receives necessary information via connections 9-1 and 9-2, and each substation device transmits and receives necessary information via connections 9-3 and 9-4. In this embodiment, the MLD wireless communication device is physically configured as a single wireless communication device (10000-1), and its configuration will be described later using FIGS. 7 and 8.

[0064] 7 is a diagram showing an example of the device configuration of wireless communication devices 1-1, 1-2, 2A, and 2B (hereinafter collectively referred to as wireless communication device 10000-1). Wireless communication device 10000-1 is configured to include an upper layer unit (upper layer processing step) 10001-1, an autonomous distributed control unit (autonomous distributed control step) 10002-1, a transmitter (transmitting step) 10003-1, a receiver (receiving step) 10004-1, and an antenna unit 10005-1. For example, wireless communication devices 1-1 and 1-2 may be AP-MLD, AP-MLD1-1 and AP-MLD1-2, and terminal device 2A and terminal device 2B may be Non-AP MLD1 and Non-AP MLD2. The STAs connected to the Non-AP MLD1 are Non-AP STAs and are also referred to as Non-AP STA2-1, Non-AP STA2-2, Non-AP STA2-3, and Non-AP STA2-4, respectively. The STAs connected to the Non-AP MLD2 are Non-AP STAs and are also referred to as Non-AP STA3-1, Non-AP STA3-2, Non-AP STA3-3, and Non-AP STA3-4, respectively.

[0065] The upper layer unit 10001-1 has MAC layer functionality and is connected to other networks and other BSSs via a DS (Distribution System). It can transmit, for example, information addressed to other wireless communication devices and control information contained in management frames or control frames to the autonomous distributed control unit 10002-1. The upper layer unit 10001-1 may also have MLME functionality, and the upper layer unit can be configured to transmit the generated frames via one or more links set in the MLD. The upper layer unit 10001-1 can be configured to include a MAC layer frame generation unit (MAC frame generation step) 10001a-1 and an upper layer control unit (upper layer control step) 10001b-1. The upper layer control unit (upper layer control step) is also simply referred to as the control unit (control step). The MAC layer frame generation unit 10001a-1 adjusts the information bits to a size that fits within the frame body and adds a MAC header and FCS to generate a MAC frame. The information bits include not only data for configuring a data frame, but also management data for configuring a management frame and control data for configuring a control frame. Upper layer control unit 10001b-1 controls not only within upper layer unit 10001-1 but also controls communication with DS and communication with the physical layer.

[0066] FIG. 8 is a diagram showing an example of the device configuration of the autonomous distributed control unit 10002-1. The autonomous distributed control unit 10002-1 is configured to include a CCA unit (CCA step) 10002a-1, a backoff unit (backoff step) 10002b-1, and a transmission determination unit (transmission determination step) 10002c-1. The CCA unit 10002a-1 can perform a status determination (including a busy or idle determination) of the radio resource using either or both of information regarding the received signal power received via the radio resource and information regarding the received signal (including information after decoding) notified from the receiving unit 10004-1. The CCA unit 10002a-1 can notify the backoff unit 10002b-1 and the transmission determination unit 10002c-1 of the status determination information of the radio resource.

[0067] The backoff unit 10002b-1 can perform a backoff procedure using radio resource state determination information. The backoff unit 10002b-1 has a countdown function for a random backoff time set within a CW. For example, when the radio resource state determination information indicates idle, the backoff counter can be counted down, and when the radio resource state determination information indicates busy, the backoff counter can be stopped. The backoff unit 10002b-1 can notify the transmission determination unit 10002c-1 of the value of the backoff counter.

[0068] The transmission decision unit 10002c-1 makes a transmission decision using either the wireless resource status decision information or the back-off counter value, or both. For example, when the wireless resource status decision information indicates idle and the back-off counter value is 0, the transmission decision unit 10002c-1 can notify the transmission decision information to the transmitting unit 10003-1. Also, when the wireless resource status decision information indicates idle, the transmission decision unit 10003-1 can notify the transmission decision information.

[0069] The transmitting unit 10003-1 includes a physical layer frame generating unit (physical layer frame generating step) 10003a-1 and a wireless transmitting unit (wireless transmitting step) 10003b-1. The physical layer frame generating unit 10003a-1 has the function of generating a physical layer frame (PPDU) based on transmission decision information notified from the transmission decision unit 10002c-1. The physical layer frame generating unit 10003a-1 performs error correction coding, modulation, precoding filter multiplication, etc. on the transmission frame sent from the upper layer. The physical layer frame generating unit 10003a-1 outputs the generated physical layer frame to the wireless transmitting unit 10003b-1.

[0070] The physical layer frame generator 10003a-1 performs error correction coding on the information bits input from the MAC layer, but the unit for performing error correction coding (coding block length) is not limited to any particular value. For example, the physical layer frame generator 10003a-1 can divide the information bit sequence input from the MAC layer into information bit sequences of a predetermined length, and perform error correction coding on each of them to create multiple coding blocks. Note that when constructing the coding blocks, dummy bits can also be inserted into the information bit sequence input from the MAC layer.

[0071] The frames generated by the physical layer frame generator 10003a-1 include control information. This control information includes information indicating in which RU (here, RU includes both frequency resources and spatial resources) data addressed to each wireless communication device is allocated. Furthermore, the frames generated by the physical layer frame generator 10003a-1 include a trigger frame that instructs the wireless communication device, which is the destination terminal, to transmit a frame. This trigger frame includes information indicating the RU to be used when the wireless communication device instructed to transmit the frame transmits the frame.

[0072] The wireless transmission unit 10003b-1 converts the physical layer frame generated by the physical layer frame generation unit 10003a-1 into a radio frequency (RF) band signal to generate a radio frequency signal. The processing performed by the wireless transmission unit 10003b-1 includes digital-to-analog conversion, filtering, frequency conversion from the baseband band to the RF band, etc.

[0073] The receiving unit 10004-1 includes a wireless receiving unit (wireless receiving step) 10004a-1 and a signal demodulation unit (signal demodulation step) 10004b-1. The receiving unit 10004-1 generates information about received signal power from the RF band signal received by the antenna unit 10005-1. The receiving unit 10004-1 can notify the CCA unit 10002a-1 of information about received signal power and information about the received signal.

[0074] The wireless receiving unit 10004a-1 has the function of converting an RF band signal received by the antenna unit 10005-1 into a baseband signal and generating a physical layer signal (e.g., a physical layer frame). The processing performed by the wireless receiving unit 10004a-1 includes frequency conversion from the RF band to the baseband, filtering, and analog-to-digital conversion.

[0075] The signal demodulation unit 10004b-1 has the function of demodulating the physical layer signal generated by the wireless receiving unit 10004a-1. The processing performed by the signal demodulation unit 10004b-1 includes channel equalization, demapping, error correction decoding, etc. The signal demodulation unit 10004b-1 can extract, for example, information contained in the physical layer header, information contained in the MAC header, and other information contained in the MAC frame from the physical layer signal. The signal demodulation unit 10004b-1 can output the extracted information to the upper layer unit 10001-1. Note that the signal demodulation unit 10004b-1 can extract any or all of the information contained in the physical layer header, information contained in the MAC header, and other information contained in the MAC frame.

[0076] Antenna unit 10005-1 has a function of transmitting the radio frequency signal generated by wireless transmission unit 10003b-1 into wireless space toward other wireless device 10000-1, and also has a function of receiving the radio frequency signal transmitted from other wireless device 10000-1.

[0077] The wireless communication device 10000-1 can include information indicating the period during which the wireless medium will be used based on the transmission opportunity acquired by the wireless communication device in the PHY header or MAC header of the frame to be transmitted, thereby allowing wireless communication devices surrounding the wireless communication device to set a NAV for that period. For example, the wireless communication device 10000-1 can include information indicating that period in the Duration field of the MAC header of the frame to be transmitted, or the Length field of the L-SIG included in the PHY header, the Length field of the L-SIG included in the PHY header, the TXOP field of the HE-SIG-A in the case of an HE PPDU, or the TXOP field of the U-SIG in the case of an EHT PPDU. The NAV period set in the wireless communication devices surrounding the wireless communication device will be referred to as the transmission opportunity (or TXOP period, simply referred to as TXOP) acquired by the wireless communication device 10000-1. The wireless communication device 10000-1 that has acquired the transmission opportunity is called a TXOP acquirer (TXOP holder). The frame type of the frame that wireless communication device 10000-1 transmits to notify the acquired transmission opportunity is not limited to any particular type, and may be a control frame (e.g., a CTS frame, an RTS frame, an MU-RTS (multi-user request to send) frame, an MU-RTS trigger frame, a BSRP (Buffer Status Report Poll) trigger frame, a CTS-to-self frame, or the like), or may be a data frame transmitted in a format such as a Non-HT PPDU, an HT PPDU, a VHT PPDU, an EHT PPDU, or a UHR-PPDU.

[0078] The wireless communication device 10000-1, which is a TXOP holder, can transmit frames to wireless communication devices other than the wireless communication device itself during the transmission opportunity. If the wireless communication device 1-1 is a TXOP holder, the wireless communication device 1-1 can transmit frames to the wireless communication device 2A during the transmission opportunity. Furthermore, the wireless communication device 1-1 can instruct the wireless communication device 2A to transmit a frame addressed to the wireless communication device 1-1 during the transmission opportunity. The wireless communication device 1-1 can transmit a trigger frame including information instructing the wireless communication device 2A to transmit a frame addressed to the wireless communication device 1-1 during the transmission opportunity. For example, the wireless communication device 1-1 may acquire a transmission opportunity for all communication bands (operation bandwidth, operation channel, etc.) in which frame transmission and reception may be performed, or may acquire a transmission opportunity for a specific communication band or communication channel, such as a communication band (transmission and reception bandwidth, transmission and reception channel) in which frames are actually transmitted and received.

[0079] The wireless communication device to which the wireless communication device 1-1 instructs frame transmission and reception within the acquired transmission opportunity period is not necessarily limited to the wireless communication device connected to the wireless communication device itself. For example, the wireless communication device can instruct wireless communication devices that are not connected to the wireless communication device itself to transmit and receive frames using a trigger frame or the like in order to cause wireless communication devices in the vicinity of the wireless communication device itself to transmit management frames such as a Reassociation frame, control frames such as RTS / MU-RTS / BSRP / CTS frames, and data frames.

[0080] Furthermore, we will also explain transmission opportunities in EDCA, a channel access method (data transmission method) different from DCF. The IEEE 802.11e standard is related to EDCA and specifies transmission opportunities from the perspective of QoS (Quality of Service) guarantee for various services such as video transmission and VoIP. Services are broadly classified into four access categories: VO (Voice), VI (Video), BE (Best Effort), and BK (Background). Generally, the order of priority is VO, VI, BE, and BK. Each access category has parameters (EDCA parameters) set as a set of CW minimum value CWmin, maximum value CWmax, length of AIFS (Arbitration IFS), which is a type of IFS, and TXOP limit, which is the upper limit of transmission opportunities. The values ​​are set to differentiate between access categories by priority. For example, by setting the CWmin, CWmax, and AIFS of VO, which has the highest priority for voice transmission, to relatively small values ​​compared to other access categories, data transmission can be prioritized over other access categories. For example, in VI, which transmits a relatively large amount of data for video transmission, setting the TXOP limit to a large value makes it possible to secure longer transmission opportunities than other access categories. In this way, the EDCA parameter values ​​for each access category are adjusted to guarantee QoS according to various services.

[0081] The signal demodulation unit 10004b-1 of the station device can perform decoding processing on the received signal at the physical layer and perform error detection. Here, the decoding processing includes decoding processing on the error correction code applied to the received signal. Here, error detection includes error detection using an error detection code (e.g., a cyclic redundancy check (CRC) code) that is pre-assigned to the received signal, and error detection using an error correction code that originally has an error detection function (e.g., a low-density parity check code (LDPC)). The decoding processing at the physical layer can be applied to each coding block.

[0082] The upper layer unit 10001-1 receives the physical layer decoding result from the signal demodulation unit 10004b-1 and decodes the MAC layer signal. The MAC layer then performs error detection and determines whether the MAC layer signal transmitted by the station device that transmitted the received frame was correctly decoded.

[0083] The number of sub-access point devices (also referred to as APs or Affiliated APs belonging to AP MLD) included in one MLD access point device and the number of substation devices (also referred to as Non-AP STAs belonging to non-AP MLD) included in one MLD station device may vary depending on the grade, class, and capabilities of each MLD wireless communication device. A high-grade, high-class, or high-capability MLD wireless communication device may have a different number of sub-wireless communication devices (sub-access point devices, substation devices) compared to a non-grade, high-class, or high-capability MLD wireless communication device. In other words, for each MLD wireless communication device located in a wireless communication system, the number of sub-wireless communication devices (sub-access point devices, substation devices) constituting each MLD wireless communication device may vary depending on the grade, class, and capabilities, and these numbers do not have to be the same.

[0084] 6 , substation device 30000-2 connects (associates) with sub-access point device 20000-2 and establishes link 1. Substation device 30000-3 connects (associates) with sub-access point device 20000-3 and establishes link 2. Substation device 30000-4 connects (associates) with sub-access point device 20000-4 and establishes link 3. In the description of this embodiment, the number of links constituting the multi-link is assumed to be three, but this is not limited to this and may be any number except 0. In the description of this embodiment, the frequency used by each link can be arbitrarily set from the 2.4 GHz band, 5 GHz band, 6 GHz band, 60 GHz band, or any other frequency band, channel, or sub-channel supported by the wireless communication system, and may vary depending on the laws and regulations of each country.

[0085] Although the wireless communication systems 2-5 and 3-5 form different BSSs, this does not necessarily mean that the ESSs (Extended Service Sets) are different. ESS refers to a service set that forms a LAN (Local Area Network). In other words, wireless communication devices that belong to the same ESS can be considered to belong to the same network from a higher layer. Furthermore, the BSSs are connected via a DS (Distribution System) to form the ESS. Each of the wireless communication systems 2-5 and 3-5 can also include multiple wireless communication devices.

[0086] This section describes an overview of the Enhanced Multi-Link Single Radio mode (EMLSR mode) and EMLSR operation according to this embodiment. The EMLSR mode allows a non-AP STA belonging to a non-AP multi-link device (Non-AP MLD) with multiple receive chains to listen for an initial control frame (ICF) transmitted by an access point (AP) belonging to an access point multi-link device (AP MLD) using a single spatial stream in a non-high throughput duplicate physical layer protocol data unit (non-HT duplicate PPDU) on a set of enabled links, and then exchange frames on the link on which the ICF was received. For example, a non-AP MLD with multiple receive chains can listen for an ICF on the EMLSR link when one or more non-AP STAs belonging to the non-AP MLD are in an awake state. That is, a non-AP STA listens for an ICF transmitted in a non-HT duplicate PPDU by an AP (affiliated AP) belonging to the AP MLD, and can then exchange frames on the link that received the ICF. Hereinafter, the term "listen" is also referred to as "listen." The ICF is not limited to specific trigger frames (e.g., a multi-user request to send (MU-RTS) trigger frame and a Buffer Status Report Poll (BSRP) frame). The initial control response (ICR) or immediate response (IR) is not limited to specific response frames (e.g., frames including an Ack frame, a Block Ack frame, a CTS frame, and a Buffer Status Report (BSR)).Regarding ICF and ICR (including IR), a CTS frame may be used as a response to an MU-RTS trigger frame, and a frame including a BSR (Buffer Status Report) may be used as a response to a BSRP trigger frame. Hereinafter, an EMLSR link refers to one or more links.

[0087] An overview of the sequence from activation of the EMLSR mode to frame exchange will be described. Here, it is assumed that the AP MLD1 and non-AP MLD1 in FIG. 9 are MLDs that support the EMLSR mode. Frame exchange in EMLSR operation is performed over one of the links established between the two MLDs. The AP MLD1 may transmit a beacon 10-1 or a probe response frame 10-3, including information indicating that it supports the EMLSR mode. For example, the AP MLD1 may include a Basic Multi-Link element in the beacon or probe response frame and set the EMLSR Support subfield in the Common Info field of the Basic Multi-Link element to 1 to transmit information indicating that it supports the EMLSR mode. Upon receiving the beacon or probe response frame, the non-AP MLD1 transmits an EML Operating Mode Notification frame 10-4. Here, the non-AP MLD1 may include information indicating that it supports the EMLSR mode in the EML Operating Mode Notification frame and transmit it to the AP MLD1. The non-AP MLD 1 can request the AP MLD 1 that supports EMLSR mode to enable the EMLSR mode by setting the EMLSR mode subfield of the EML Control field of the EML Operating Mode Notification frame to 1. In addition, the EMLSR link to be enabled can be specified by setting the corresponding bit position of the EMLSR Link Bitmap subfield of the EML Control field of the EML Operating Mode Notification frame to 1. Upon receiving a response frame to the EML Operating Mode Notification frame, the non-AP MLD 1 waits for the ICF 10-5 on the enabled EMLSR link.Here, the non-AP MLD1 that supports the EMLSR mode transmits an ICR 10-6 on the link that received the ICF 10-5. The AP MLD1 can start frame exchange with the non-AP MLD1 on the link that received the ICR 10-6. The non-AP MLD1 may transmit a (re)association request frame that includes information indicating that it supports the EMLSR mode.

[0088] An overview of the frame exchange sequence on an EMLSR link is shown in Figure 10. Figure 10 illustrates a frame exchange sequence using ICF and ICR between non-AP STAs (Non-AP STA1, Non-AP STA2) belonging to a non-AP MLD in EMLSR mode and APs (Affiliated AP1, Affiliated AP2) belonging to an AP MLD. An ICF can be used to initiate frame exchange with one or more non-AP STAs belonging to a non-AP MLD in EMLSR mode. Affiliated AP1 transmits an ICF to non-AP STA1 via one of the EMLSR links. For example, in Figure 10, non-AP STA1 receives ICFs 11-11 to 11-14, and after a SIFS, transmits ICRs 11-21 to 11-24 to Affiliated AP1 via link 1, thereby initiating frame exchange on link 1. Affiliated AP 1, which has received ICRs 11-21 to 11-24 from Non-AP STA 1, can transmit, for example, A-MPDUs as frames 11-31 to 11-34 after SIFS, and can receive a Block Ack after SIFS (Block Ack not shown).

[0089] In FIG. 10, the operation bandwidth of the AP-MLD that has established a link with the Non-AP MLD is 80 MHz (subchannels CH1 to CH4, each with a 20 MHz bandwidth), but this is merely an example and is not limiting. In FIG. 10, Non-AP STA1 and Non-AP STA2 form receive chains (s) to receive ICFs 11-11 to 11-14 and are shown in a standby state. Note that one of CH1 to CH4 is set as the primary channel. The determination of whether to transmit a data frame in EMLSR operation depends on the status of this primary channel. For example, if CH1 is set as the primary channel, Affiliated AP1 performs carrier sensing on CH1 after a random backoff time and determines that CH1 is idle, and may transmit ICF 11-11 on CH1. Furthermore, if the primary channel CH1 is busy, the carrier sensing procedure on channels CH2 to CH4 other than the primary channel cannot proceed. Meanwhile, Non-AP STA1, which has received the ICF, checks the wireless channel status of CH1 to CH4 and determines that they are in an idle state. If this is the case, it transmits ICRs 11-21 to 11-24 indicating this to CH1 to CH4, respectively. Affiliated AP1 then receives ICRs 11-21 to 11-24. Affiliated AP1 then determines that the wireless channels of CH1 to CH4 are available for use, and can transmit data frames 11-31 to 11-34 using the entire 80 MHz channel bandwidth. Details (frame configuration and sequence) from activation of the EMLSR mode to frame exchange are described below.

[0090] For EMLSR mode activation, the EMLSR mode subfield and EMLMR mode subfield of the EML Control field of the EML Operating Mode Notification frame are used to enable or disable EMLSR mode and EMLMR mode, respectively. For example, if Non-AP MLD supports EMLSR operation, a value of 0 in the EMLSR mode subfield indicates that EMLSR mode is disabled for Non-AP MLD, and a value of 1 in the EMLSR mode subfield indicates that EMLSR mode is enabled for Non-AP MLD. If Non-AP MLD does not support EMLSR operation or if the EMLMR mode subfield is 1, the EMLSR mode subfield is set to 0. Also, if the EMLSR mode subfield is set to 1, the EMLSR / EMLMR Link Bitmap subfield becomes the EMLSR Link Bitmap subfield. If the EMLMR Mode subfield is set to 1, the EMLSR / EMLMR Link Bitmap subfield is the EMLMR Link Bitmap subfield. If the EMLSR Mode subfield is set to 0 and the EMLMR Mode subfield is also set to 0, the EMLSR / EMLMR Link Bitmap subfield is not present. The EML Operating Mode Notification frame sets these subfields to non-zero values ​​only if the receiving MLD supports the corresponding mode. Note that an MLD can also indicate whether it supports the EMLSR / EMLSR mode in the EML Capabilities field of the Basic Multi-Link element it sends.

[0091] For activation of the EMLSR mode, an AP MLD with Dot11EHTEMLSREnablementOnOneLinkImplemented set to true MUST set the EMLSR Enablement On One Link Support subfield of the Extended MLD Capabilities And Operations subfield of the Common Info field of the Basic Multi-Link element to 1. If a Non-AP MLD has received a Basic Multi-Link element with the EMLSR Enablement On One Link Support subfield set to 1 from the connected AP MLD, the Non-AP MLD can set a single bit position to 1 in the EMLSR Link Bitmap subfield of the EML Control field of the EML Operating Mode Notification frame when requesting the connected AP MLD to enable the EMLSR mode. Otherwise, when a Non-AP MLD requests the connected AP MLD to enable EMLSR mode, it MUST NOT set a single bit position to 1 in the EMLSR Link Bitmap subfield of the EML Control field of the EML Operating Mode Notification frame. When an AP MLD with Dot11EHTEMLSROPtionActivated set to true responds to a received EML Operating Mode Notification frame, it sets the EMLSR mode subfield to the value obtained from the EMLSR mode subfield of that frame. The value of the EMLSR Link Bitmap subfield of the EML Operating Mode Notification frame last sent by the Non-AP MLD indicates the EMLSR link.

[0092] When a non-AP MLD with Dot11EHTEMLSROOptionActivated set to true (re)associates with an AP MLD, EMLSR mode is disabled by default. An MLD with Dot11EHTEMLSROOptionActivated set to true must set the EML Capabilities Present subfield to 1 and the EMLSR Support subfield in the Common Info field of the Basic Multi-Link element to 1. The Basic Multi-Link element of the AP MLD corresponding to the BSSID being transmitted is always included in beacons and probe response frames transmitted by APs (affiliated APs) belonging to the AP MLD. This applies to all management frames containing the Basic Multi-Link element, except for authentication frames. An MLD with Dot11EHTEMLSROOptionActivated set to false and dot11EHTEMLMROOptionActivated set to true MUST set the EML Capabilities Present subfield to 1 and the EMLSR Support subfield of the EML Capabilities subfield to 0. An MLD with Dot11EHTEMLSROOptionActivated set to false and dot11EHTEMLMROOptionActivated set to false MUST set the EML Capabilities Present subfield to 0.

[0093] Regarding activation of EMLSR mode, when a Non-AP MLD with Dot11EHTEMLSROOptionActivated set to true enables EMLSR mode on an EMLSR link, a Non-AP STA belonging to the Non-AP MLD must send an EML Operating Mode Notification frame with the EMLSR mode subfield of the EML Control field set to 1 to an AP (Affiliated AP) belonging to an AP MLD with dot11EHTEMLSROOptionActivated set to true. Furthermore, when a Non-AP MLD with Dot11EHTEMLSROOptionActivated set to true enables the EMLSR mode on an EMLSR link, an AP (Affiliated AP) belonging to the AP MLD should transmit an EML Operating Mode Notification frame to a Non-AP STA belonging to the Non-AP MLD in awake state within the Transition timeout interval in response to a received EML Operating Mode Notification frame after the AP MLD is ready to provide service to the Non-AP MLD in EMLSR operation, and the following rule applies: Regarding the above rule, the Transition timeout interval must be indicated by the AP (Affiliated AP) belonging to the AP MLD in the Transition Timeout subfield of the EML Capabilities subfield of the Basic Multi-Link element of all Management frames containing the Basic Multi-Link element, except for Authentication frames.Furthermore, for the above rule, the Transition timeout interval begins at the end of a PPDU [+SigExt (Signal Extension)] transmitted by an AP (Affiliated AP) belonging to the AP MLD that returns an Immediate Acknowledgement to an EML Operating Mode Notification frame transmitted by a Non-AP STA belonging to the Non-AP MLD. The EML Control field of the EML Operating Mode Notification frame transmitted by the AP (Affiliated AP) belonging to the AP MLD is set to the same value as the EML Control field of the received EML Operating Mode Notification frame.

[0094] Regarding EMLSR mode activation, if a Non-AP MLD with Dot11EHTEMLSROOptionActivated set to true enables the EMLSR mode on an EMLSR link, the Non-AP MLD can operate the EMLSR mode on the EMLSR link, and therefore other Non-AP STAs belonging to the Non-AP MLD can also operate the EMLSR mode on the EMLSR link corresponding to the other Non-AP STAs. The other Non-AP STAs may transition to active mode without transmitting a frame with the Power Management subfield set to 0, even if they have not transmitted an EML Operating Mode Notification frame. This transition to active mode must occur at the end of the transition timeout interval, or immediately after transmitting an acknowledgment in response to an EML Operating Mode Notification frame received from one of the APs (Affiliated APs) belonging to the AP MLD before the end of the transition timeout interval, whichever occurs first. Furthermore, the other Non-AP STAs must not transmit frames with the Power Management subfield set to 1 until they receive an EML Operating Mode Notification frame from one of the APs (Affiliated APs) belonging to the AP MLD, or before the end of the transition timeout interval, whichever occurs first.

[0095] Regarding the activation of the EMLSR link, the Non-AP MLD may operate in EMLSR mode on a designated set of enabled links between the connected AP MLDs. The designated set of enabled links to which the EMLSR mode is applied is called the EMLSR link. The EMLSR link must be indicated by setting the bit position corresponding to the link ID value of the EMLSR link to 1 in the EMLSR Link Bitmap subfield of the EML Control field of the EML Operating Mode Notification frame. When the EMLSR mode is enabled in a Single Radio Non-AP MLD, a Non-AP STA belonging to the Non-AP MLD operating on a link whose bit position in the EMLSR Link Bitmap subfield is equal to 0 must be in the Doze state if another Non-AP STA belonging to the Non-AP MLD is already in the Awake state on one of the EMLSR links.

[0096] Regarding frame exchange on the EMLSR link, when a non-AP MLD operates in EMLSR mode with an AP MLD that supports EMLSR mode, it can listen on one of the EMLSR links. The ICF must be an MU-RTS trigger frame or a BSRP trigger frame. The number of spatial streams in a response to a BSRP trigger frame is limited to one, and this number must be indicated in the BSRP trigger frame. Note that either an MU-RTS trigger frame or a BSRP trigger frame can be used as the ICF to initiate frame exchange. The non-AP MLD must be able to wake up non-AP STAs on the link between it and the associated AP MLD and listen on the EMLSR link. This listening operation includes frame exchanges initiated by CCA and AP MLD, i.e., receiving an ICF.

[0097] Regarding frame exchange over EMLSR links, when a Non-AP MLD is operating in EMLSR mode with an AP MLD that supports EMLSR mode, an AP (Affiliated AP) that initiates a frame exchange with the Non-AP MLD over one of the EMLSR links must initiate a frame exchange that is neither group addressed data nor group addressed management frames. However, when initiating the frame exchange, an AP (Affiliated AP) that is affiliated with the AP MLD must send an ICF to the Non-AP MLD, subject to the following restrictions. The ICF must be transmitted in non-HT PPDU or non-HT duplicate PPDU format using a rate of 6 Mb / s, 12 Mb / s, or 24 Mb / s. Non-AP MLD MUST indicate the EMLSR padding delay, which is the minimum MAC padding duration of the ICF, in the EMLSR padding delay subfield of the EML capabilities subfield of the Common Info field of the Basic Multi-Link element carried in the (re)association request frame sent by the Non-AP MLD. Non-AP MLD can also update the EMLSR padding delay by including the updated EMLSR padding delay duration in the EML Parameter Update field of the EML Operating Mode Notification frame. APs belonging to AP MLD (affiliated APs) must set the length of the Padding field in the ICF according to the rules in the Padding for a Trigger frame and ensure that the MAC padding duration of the ICF is equal to or greater than the EMLSR padding delay last indicated by the Non-AP MLD.This is indicated either by the EMLSR padding delay subfield of the EML Capabilities subfield of the Common Info field of the Basic Multi-Link element or by the EMLSR padding delay subfield of the EMLSR parameter update field of the most recently transmitted EML Operating Mode Notification frame.

[0098] Regarding frame exchange on the EMLSR link, when a Non-AP MLD operates in EMLSR mode with an AP MLD that supports EMLSR mode, if a Non-AP STA belonging to the listening Non-AP MLD receives an MU-RTS trigger frame or BSRP trigger frame addressed to itself, the Non-AP STA responds according to the rules in Non-AP STA behavior for UL MU operation. However, if a frame exchange initiated by an ICF on one EMLSR link overlaps with a group-addressed frame transmission on another EMLSR link on which the Non-AP STA is attempting to receive a group-addressed frame, the Non-AP STA does not respond. Furthermore, after a Non-AP STA belonging to the Non-AP MLD receives an ICF and sends an immediate response (IR) frame to the AP MLD in response, the Non-AP STA can send and receive frames on the link on which it received the ICF and will not send and receive frames on other EMLSR links until the frame exchange is complete. Furthermore, according to the spatial stream capability, operating mode, and minimum MAC frame padding duration in the padding field of the ICF, a non-AP STA belonging to the non-AP MLD is capable of receiving a PPDU transmitted using one or more spatial streams on the link on which the ICF was received, SIFS after completing the response frame transmission requested by the ICF. During frame exchange, other APs (other affiliated APs) belonging to the AP MLD do not transmit frames to other non-AP STAs belonging to the non-AP MLD on other EMLSR links.

[0099] Regarding frame exchange over an EMLSR link, when a Non-AP MLD is operating in EMLSR mode with an AP MLD that supports EMLSR mode, the Non-AP MLD indicates its EMLSR Transition Delay in the EMLSR Transition Delay subfield of the EML Capabilities subfield in the Common Info field of the Basic Multi-Link element carried in the (re)association request frame it transmits. The Non-AP MLD can update its EMLSR Transition Delay by including an EMLSR Parameter Update field in an EML Operating Mode Notification frame. If the EMLSR Parameter Update field is present in the EML Operating Mode Notification frame, the EMLSR Link Bitmap subfield of the EML Control field contains a value different from the EMLSR Link Bitmap value included in the EML Operating Mode Notification frame last transmitted by the Non-AP MLD.

[0100] Regarding frame exchange on the EMLSR link, when the Non-AP MLD is operating in EMLSR mode with an AP MLD that supports EMLSR mode, the Non-AP MLD will terminate frame exchange by returning to listening operation on the EMLSR link after the EMLSR Transition Delay Time last indicated by the Non-AP MLD, provided that any of the following conditions is met: The above condition occurs when the MAC of a Non-AP STA belonging to the Non-AP MLD does not receive a PHY-RXSTART.indication primitive within a timeout interval (aSIFSTime + aSlotTime + aRxPHYStartDelay; aRxPHYStartDelay is 20 μs) after receiving an ICF, and the timeout interval starts at the end of a PPDU sent by a Non-AP STA belonging to the Non-AP MLD in response to the last frame received from an AP (Affiliated AP) belonging to the AP MLD, or at the end of reception of a PPDU containing a frame for the Non-AP STA from an AP (Affiliated AP) belonging to the AP MLD that does not require an immediate response. Alternatively, the MAC of a non-AP STA belonging to a non-AP MLD receives a PHY-RXSTART.indication primitive within the timeout interval (aSIFSTime + aSlotTime + aRxPHYStartDelay) after receiving an ICF, and the non-AP STA does not detect any of the following frames in the PPDU corresponding to the PHY-RXSTART.indication.The frame is an individual addressed frame whose RA is equal to the MAC address of a Non-AP STA belonging to the Non-AP MLD, a trigger frame whose User Info field is addressed to a Non-AP STA belonging to the Non-AP MLD, a CTS-to-self frame whose RA is equal to the MAC address of an AP (Affiliated AP) belonging to the AP MLD, a Multi-STA BlockAck frame whose Per AID TID Info field is addressed to a Non-AP STA belonging to the Non-AP MLD, or an NDP Announcement frame whose STA Info field is addressed to a Non-AP STA belonging to the Non-AP MLD and has a Sounding NDP. The above condition occurs when a Non-AP STA belonging to the Non-AP MLD does not respond to a frame requiring an immediate response after SIFS, which it last received from an AP (Affiliated AP) belonging to the AP MLD, after receiving an ICF.

[0101] Regarding frame exchange over an EMLSR link, when a Non-AP MLD operates in EMLSR mode with an AP MLD that supports EMLSR mode, if an AP (affiliated AP) belonging to the AP MLD intends to continue frame exchange with a Non-AP STA belonging to the Non-AP MLD and does not receive a response frame from the Non-AP STA for its last transmitted frame requiring an immediate response after SIFS, it should send another ICF addressed to the Non-AP STA belonging to the Non-AP MLD before the TXNAV timer expires. Also, any Non-AP STA belonging to the Non-AP MLD operating on one of the EMLSR links can initiate frame exchange with the AP MLD. When a Non-AP STA belonging to the Non-AP MLD initiates a TXOP, the Non-AP MLD returns to listening operation on the EMLSR link after the TXOP ends and the EMLSR Transition Delay Time indicated by the Non-AP MLD has elapsed.

[0102] Regarding frame exchange over an EMLSR link, when a Non-AP MLD operates in EMLSR mode with an AP MLD that supports EMLSR mode, a Non-AP STA belonging to the Non-AP MLD operating in EMLSR mode does not need to send an ICF to initiate frame exchange with the AP MLD. In this case, the Non-AP STA accesses the wireless medium (WM) according to the UL MU CS rules, which also apply to the sounding sequence. When an AP (affiliated AP) belonging to the AP MLD sends an ICF to initiate frame exchange with multiple Non-AP MLDs operating in EMLSR mode, the AP MLD calculates the length of the Padding field in the ICF according to a predetermined rule and ensures that the MAC frame padding time in the ICF is equal to or greater than the maximum value indicated in the EMLSR Padding Delay subfield of the Basic Multi-Link element received from the Non-AP MLD where frame exchange is initiated. A Non-AP STA belonging to a Non-AP MLD operating in EMLSR mode can receive a beacon frame at the scheduled beacon transmission time (ie, TBTT).

[0103] Regarding the frame exchange sequence of EMLSR operation, the structure of the MU-RTS trigger frame, which is an ICF, is described below. Here, it is assumed that the User Info field of the MU-RTS trigger frame is the HE variant User Info field. The HE variant User Info field is defined for all trigger frame variants except for the NFRP trigger frame, MU-RTS TXS trigger frame, and Ranging trigger frame. The User Info field of the MU-RTS trigger frame does not include the Trigger Dependent Common Info subfield and the Trigger Dependent User Info subfield, and includes the AID12, RU allocation, UL FEC Coding Type, UL HE-MCS, UL DCM, SS Allocation / RA-RU Information, UL Target Receive Power, and Reserved fields. Note that the UL Target Receive Power field is reserved. If the AID12 subfield is 2046, the remaining subfields of the User Info field are reserved, except for the RU Allocation subfield, which indicates the location of unallocated RUs. If the AID12 subfield is 4095, the remaining subfields of the User Info field are not present and represent the start of a padding field. The RU Allocation subfield and the UL BW subfield of the Common Info field specify the size and location of the RU. If the UL BW subfield indicates a 20 MHz, 40 MHz, or 80 MHz PPDU, B0 of the RU Allocation subfield is set to 0.If the UL BW subfield indicates 80+80 MHz or 160 MHz, B0 of the RU Allocation subfield is set to 0 to indicate that the RU allocation applies to the primary 80 MHz channel, or to 1 to indicate that it applies to the secondary 80 MHz channel.

[0104] When a Non-AP EHT STA is identified by the AID12 subfield of the User Info field of the MU-RTS Trigger frame from the EHT AP and any of the following conditions are met, the User Info field of the MU-RTS Trigger frame becomes the EHT variant User Info field: the bandwidth of the EHT MU PPDU or non-HT duplicate PPDU carrying the MU-RTS Trigger frame is 320 MHz, and the EHT MU PPDU or non-HT duplicate PPDU carrying the MU-RTS Trigger frame is punctured. Otherwise, the User Info field may be either the HE variant User Info field or the EHT variant User Info field.

[0105] The encoding of the RU Allocation subfield in the MU-RTS trigger frame is described below. The RU Allocation subfield of the User Info field sent to a non-AP STA indicates whether the CTS frame is transmitted on the primary 20 MHz channel, primary 40 MHz channel, primary 80 MHz channel, primary 160 MHz channel, 80+80 MHz channel (HE only), or 320 MHz channel (EHT, UHR only). B0 of the RU Allocation subfield is set to 0 to indicate the primary 20 MHz channel, primary 40 MHz channel, and primary 80 MHz channel. For primary 160 MHz, 80+80 MHz, and 320 MHz indications, B0 of the RU Allocation subfield is set to 1. B7-B1 of the RU Allocation subfield are set to indicate the primary 20 MHz channel as follows: The RU Allocation subfields B7-B1 are set to indicate the primary 40 MHz channel as follows: 61 if the primary 20 MHz channel is the only 20 MHz channel or the lowest frequency 20 MHz channel within the primary 40 MHz channel or primary 80 MHz channel; 62 if the primary 20 MHz channel is the second lowest frequency 20 MHz channel within the primary 40 MHz channel or primary 80 MHz channel; 63 if the primary 20 MHz channel is the third lowest frequency 20 MHz channel within the primary 80 MHz channel; or 64 if the primary 20 MHz channel is the fourth lowest frequency 20 MHz channel within the primary 80 MHz channel. The RU Allocation subfields B7-B1 are set to indicate the primary 40 MHz channel as follows: 65 if the primary 40 MHz channel is the only 40 MHz channel or the lowest frequency 40 MHz channel within the primary 80 MHz channel; or 66 if the primary 40 MHz channel is the second lowest frequency 40 MHz channel within the primary 80 MHz channel.The RU Allocation subfield B7-B1 is set to 67 to indicate the primary 80 MHz channel.

[0106] Regarding the frame exchange sequence for EMLSR operation, the CTS frame for the MU-RTS trigger frame, which is an ICR, will be explained below. When a non-AP STA receives an MU-RTS trigger frame, the non-AP STA shall start transmitting the CTS frame at the SIFS time boundary after the end of the received PPDU. However, this is only applicable if the non-AP STA is not NSTR (Nonsimultaneous Transmit and Receive) limited and all of the following conditions are met: The first condition is when one of the User Info fields in the MU-RTS trigger frame is directed to a non-AP STA, i.e., the AID12 subfield is equal to the 12 LSB of the non-AP STA's AID, and the MU-RTS trigger frame is transmitted from an affiliated AP connected to the non-AP STA, or when the non-AP STA is connected to an affiliated AP corresponding to the non-transmitted BSSID and has set the Rx Control Frame To MultiBSS subfield of the HE Capabilities element to 1, indicating that it supports receiving control frames with the TA field set to the transmitted BSSID. The second condition is when the UL MU CS condition indicates that the medium is idle. If the non-AP STA is NSTR limited and the above conditions are met, the non-AP STA may start transmitting a CTS frame from the SIFS time boundary after the end of the received PPDU. If the above conditions are not met, the Non-AP STA must not transmit a CTS frame.

[0107] Regarding the CTS frame in response to the MU-RTS trigger frame, the non-AP EHT STA identified in the User Info field of the MU-RTS trigger frame determines whether the User Info field is the HE variant User Info field or the EHT variant User Info field. The CTS frame in response to the MU-RTS trigger frame shall be transmitted in the RU indicated in the HE / EHT variant User Info field, excluding any punctured 20 MHz subchannels indicated in the Disabled Subchannel Bitmap subfield of the EHT Operation element. If the User Info field of the MU-RTS trigger frame is the EHT variant User Info field, it includes the AID12 subfield, RU Allocation subfield, UL FEC Coding Type subfield, UL EHT-MCS subfield, Reserved subfield, SS Allocation subfield, UL Target Receive Power subfield, PS160 subfield, and Trigger Dependent User Info subfield. This EHT variant User Info field is defined for all trigger frame variants except the NFRP trigger frame and the MU-RTS TXS trigger frame. The AID 12 subfield of the EHT variant User Info field has a value between 1 and 2006, and values ​​within this range indicate connected Non-AP STAs with an AID equal to that value.The RU Allocation subfield in the EHT variant User Info field of a trigger frame that is not an MU-RTS trigger frame, together with the UL BW subfield in the Common Info field, the UL BW Extension subfield in the Special User Info field, and the PS160 subfield in the EHT variant User Info field, specifies the size and location of the RU or MRU (Multi RU). The mapping of B7-B1 in the RU Allocation subfield is defined together with the setting of B0 in the RU Allocation subfield and the setting of the PS160 subfield in the EHT variant User Info field. The bandwidth is obtained from the combination of the UL BW subfield and the UL Bandwidth Extension subfield.

[0108] This embodiment describes EMLSR operation on a secondary channel. Hereinafter, this operation will be referred to as EMLSR Secondary Channel operation (also referred to as EMLSR SC operation or EMLSR Secondary Channel Access). An MLD supporting the EMLSR SC mode is capable of accessing a non-primary channel (secondary channel) on an EMLSR link and exchanging frames on the secondary channel. EMLSR SC operation is an operation that enables a non-AP MLD with multiple active receive chains to listen for an ICF transmitted using a single spatial stream from an AP (affiliated AP) belonging to the AP MLD in a set of enabled links, access a secondary channel on the link that received the ICF, and exchange frames on the secondary channel. Hereinafter, an EMLSR link enabled between MLDs supporting the EMLSR SC mode will be referred to as an EMLSR SC link. The names of the fields and subfields of a frame related to the EMLSR SC operation are not limited to those described in this embodiment. Regarding ICF and ICR (including IR), a CTS frame may be used as a response to an MU-RTS trigger frame, and a frame including a BSR (Buffer Status Report) may be used as a response to a BSRP trigger frame.

[0109] The EMLSR SC operation according to this embodiment is an operation in which the EMLSR mode is activated and then used. Therefore, when the EMLSR SC mode is not used, the same operation as the EMLSR operation can be performed. In the EMLSR SC operation, both the link switching and the transition from the primary channel to the secondary channel processes required in the EMLSR operation are simultaneously performed, which is expected to reduce delay.

[0110] An overview of the sequence from activation of the EMLSR SC mode to frame exchange will be described below. Here, the description will be made using FIG. 9 . AP MLD1 and Non-AP MLD1 in the figure are MLDs supporting the EMLSR mode and the EMLSR SC mode, and illustrate an example of frame exchange performed over one of the links established between the two MLDs. AP MLD1 supporting the EMLSR mode may transmit a beacon 10-1 or a probe response frame 10-3, including information indicating support for the EMLSR SC mode. For example, AP MLD1 may include a Basic Multi-Link element in the beacon or probe response frame, set the EMLSR Support subfield in the Common Info field of the Basic Multi-Link element to 1, and further include information indicating support for EMLSR Secondary Channel Access in the Common Info field of the Basic Multi-Link element, thereby transmitting information indicating support for the EMLSR SC mode. That is, the AP MLD1 can indicate that it supports the EMLSR SC mode and supports EMLSR SC operation (EMLSR Secondary Channel Access) by setting the EMLSR Secondary Support subfield and the EMLSR Secondary Channel Access Support subfield in the Common Info field of the Basic Multi-Link element to 1. The non-AP MLD1 that receives the beacon or probe response frame transmits an EML Operating Mode Notification frame 10-4. Here, a non-AP MLD1 that supports the EMLSR mode may include information indicating that it supports the EMLSR SC mode in the EML Operating Mode Notification frame and transmit it to the AP MLD1.For example, the non-AP MLD1 can request the AP MLD1 supporting the EMLSR mode to enable the EMLSR SC mode by setting the EMLSR Secondary Channel Access Support subfield of the EML Control field of the EML Operating Mode Notification frame to 1. The EMLSR SC link to be enabled can be specified by setting the bit position corresponding to the EMLSR SC link in the EMLSR Link Bitmap subfield of the EML Control field of the EML Operating Mode Notification frame to 1. Upon receiving a response frame to the EML Operating Mode Notification frame, the non-AP MLD1 waits for the ICF 10-5 on the enabled EMLSR SC link. Here, the AP MLD1 supporting the EMLSR SC mode transmits information about the secondary channel to the ICF 10-5 via one of the EMLSR SC links established between the AP MLD1 and the non-AP MLD1. The information about the secondary channel, which will be described later, is necessary for frame exchange on the secondary channel even when the primary channel is busy. Here, the non-AP MLD1 that supports the EMLSR SC mode accesses the secondary channel of the link that received the ICF 10-5 and transmits an ICR 10-6 on the secondary channel. The AP MLD1 can start frame exchange with the non-AP MLD1 on the secondary channel that received the ICR 10-6. Note that the non-AP MLD1 may transmit information indicating that it supports the EMLSR SC mode by including it in a (re)association request frame. Hereinafter, the EMLSR SC link refers to one or more links.

[0111] An overview of the frame exchange sequence on the EMLSR SC link is shown in Figure 13. Figure 13 shows the frame exchange sequence using ICF / ICR between non-AP STAs (Non-AP STA1, Non-AP STA2) belonging to the non-AP MLD in EMLSR SC mode and APs (Affiliated AP1, Affiliated AP2) belonging to the AP MLD. It is assumed that CH1 in Figure 13 is configured as the primary channel, and CH2 to CH4 adjacent to CH1 are configured as secondary channels. Link 1 and Link 2 represent the EMLSR SC link. Non-AP STA1 and Non-AP STA2 form receive chains to receive ICFs and are in standby mode. Affiliated AP1 can send ICFs 11-11 to 11-14, which contain information about the secondary channel, to Non-AP STA1 via one of the EMLSR SC links. Non-AP STA1 sends an ICR via the secondary channel in response to the ICF. However, the secondary channel must be included in the information about the secondary channel included in the ICF. For example, the information about the secondary channel may be, when CH1 is the primary channel, CH2, CH3, and CH4 are 20 MHz secondary channels, when CH1 and CH2 are 40 MHz primary channels, the combination of CH3 and CH4 is 40 MHz secondary channel, or when CH3 is punctured, the combination of CH2 and CH4, which are not adjacent to each other, is set as the 40 MHz secondary channel. In this way, Affiliated AP1 can instruct or indicate candidates for which secondary channel an ICR can be transmitted to Non-AP STA1.For example, if a non-AP STA1 that supports the EMLSR SC mode checks the wireless channel conditions and determines that only the secondary channels CH3 and CH4 are idle, it may transmit an ICR on CH3 and CH4 in response to the ICF to exchange frames on the secondary channels. However, in EMLSR SC operation, frame exchange must not be performed on Punctured channels, as in EMLSR operation.

[0112] In Figure 13, Non-AP STA1 receives an ICF on CH1 to CH4. After checking the wireless channel status and determining that only CH4 is idle, it can transmit ICR11-24 on CH4. Note that CH4 is a secondary channel, configured based on the secondary channel information included in the ICF by Affiliated AP1. Upon receiving ICR11-24, Affiliated AP1 transmits data frame 11-34 using a channel bandwidth of 20 MHz. While the bandwidth for EMLSR SC operation in the figure is 80 MHz (subchannels CH1 to CH4, each with a 20 MHz bandwidth), this is merely an example and is not limiting. Details (frame configuration and sequence) of the EMLSR SC mode, from activation to frame exchange, are described below.

[0113] For EMLSR SC mode activation, the Secondary Channel Access Mode subfield of the EML Control field of the EML Operating Mode Notification frame is used to enable or disable the EMLSR SC mode. Figure 11 shows an example of the EML Control field of the EML Operating Mode Notification frame including the Secondary Channel Access Mode subfield. For example, if non-AP MLD supports EMLSR SC operation, a value of 0 in the Secondary Channel Access Mode subfield may indicate that the EMLSR SC mode is disabled for non-AP MLD, and a value of 1 in the Secondary Channel Access Mode subfield may indicate that the EMLSR SC mode is enabled for non-AP MLD. If non-AP MLD does not support EMLSR SC operation or if the EMLSR / EMLMR Mode subfield is 0, the Secondary Channel Access Mode subfield is set to 0. Also, if the Secondary Channel Access Mode subfield and the EMLSR Mode subfield are set to 1, the EMLSR / EMLMR Link Bitmap subfield becomes the EMLSR Link Bitmap subfield. Hereinafter, the EMLSR Link Bitmap subfield in EMLSR SC operation is also referred to as the EMLSR SC Link Bitmap subfield. If the EMLSR Mode subfield is set to 0 and the EMLMR Mode subfield is also set to 0, the EMLSR / EMLMR Link Bitmap subfield may not be present.The EML Operating Mode Notification frame may set these subfields to non-zero values ​​only if the receiving MLD supports the corresponding modes. Note that the MLD may also indicate whether it supports the EMLSR SC mode in the EML Capabilities field of the Basic Multi-Link element it sends.

[0114] For EMLSR SC mode activation, an AP MLD with Dot11EHTEMLSRSecondaryChannelAccessEnabledOnOneLinkImplemented set to true may be an AP MLD supporting EMLSR SC operation. Here, the AP MLD may set the EMLSR Secondary Channel Enablement On One Link Support subfield of the Extended MLD Capabilities And Operations subfield of the Common Info field of the Basic Multi-Link element to 1. If a non-AP MLD receives a Basic Multi-Link element with the EMLSR Secondary Channel Enablement On One Link Support subfield set to 1 from the associated AP MLD, the non-AP MLD may set a single bit position in the EMLSR Link Bitmap subfield of the EML Control field of the EML Operating Mode Notification frame to 1 when requesting the associated AP MLD to enable EMLSR SC mode. In other cases, when a Non-AP MLD requests the connected AP MLD to enable the EMLSR SC mode, it may not set a single bit position to 1 in the EMLSR Link Bitmap subfield of the EML Control field of the EML Operating Mode Notification frame. Note that the name of Dot11EHTEMLSRSecondaryChannelAccessEnabledOnOneLinkImplemented is not limited to this.

[0115] An AP MLD with Dot11EHTEMLSRSSecondaryChannelAccessOptionActivated set to true may be an AP MLD supporting EMLSR SC operation. Here, when responding to a received EML Operating Mode Notification frame, the AP MLD sets the Secondary Channel Access Mode subfield to the value obtained from the Secondary Channel Access Mode subfield of the frame. The value of the EMLSR Link Bitmap subfield of the EML Operating Mode Notification frame last sent by the non-AP MLD indicates the EMLSR SC link. Note that if Dot11EHTEMLSREnablementOnOneLinkImplemented is false, Dot11EHTEMLSRSecondaryChannelAccessEnabledOnOneLinkImplemented may not be set to true. Note that the names of Dot11EHTEMLSRSecondaryChannelAccessOptionActivated and Dot11EHTEMLSRSecondaryChannelAccessEnabledOnOneLinkImplemented are not limited to these.

[0116] Regarding EMLSR SC mode activation, when a Non-AP MLD with Dot11EHTEMLSRSecondaryChannelAccessOptionActivated is true (re)associates with an AP MLD, EMLSR SC mode may be disabled by default. An MLD with Dot11EHTEMLSROptionActivated and Dot11EHTEMLSRSecondaryChannelAccessOptionActivated is true may set the EML Capabilities Present subfield to 1 and the EMLSR Secondary Channel Access Support subfield of the Common Info field of the Basic Multi-Link element to 1. 12 shows an example of the Common Info field of a Basic Multi-Link element including an EMLSR Secondary Channel Access Support subfield. The Basic Multi-Link element of an AP (Affiliated AP) belonging to the AP MLD corresponding to the transmitted BSSID is always included in the beacon and probe response frames transmitted by the Affiliated AP. This may be applied to all or some Management frames including the Basic Multi-Link element, excluding Authentication frames. An MLD in which Dot11EHTEMLSROptionActivated is false and dot11EHTEMLMROptionActivated is true may set the EML Capabilities Present subfield to 1, and the EMLSR Support subfield and EMLSR Secondary Channel Access Support subfield of the EML Capabilities subfield to 0.An MLD with Dot11EHTEMLSROOptionActivated equal to false and dot11EHTEMLMROOptionActivated equal to false MUST set the EML Capabilities Present subfield to 0. Note that if Dot11EHTEMLSROOptionActivated is false, Dot11EHTEMLSRSSecondaryChannelAccessOptionActivated may not be set to true.

[0117] Regarding activation of the EMLSR SC mode, a non-AP MLD with Dot11EHTEMLSRSecondaryChannelAccessOptionActivated set to true may be considered to support EMLSR operation when it enables the EMLSR SC mode. Here, the non-AP MLD can indicate that the EMLSR SC mode is enabled by including a Secondary Channel Access Mode subfield in the EML Control field of an EML Operating Mode Notification frame and setting the Secondary Channel Access Mode subfield to 1. A non-AP STA belonging to the non-AP MLD may transmit an EML Operating Mode Notification frame with the Secondary Channel Access Mode subfield set to 1 to an AP (affiliated AP) belonging to an AP MLD with Dot11EHTEMLSRSecondaryChannelAccessOptionActivated set to true. Also, when a Non-AP MLD with Dot11EHTEMLSROOptionActivated set to true enables EMLSR SC mode on an EMLSR link, an Affiliated AP belonging to the AP MLD may transmit an EML Operating Mode Notification frame to a Non-AP STA belonging to the Non-AP MLD in the awake state within the Transition timeout interval in response to a received EML Operating Mode Notification frame after the AP MLD is ready to provide service to the Non-AP MLD with EMLSR SC operation, and the following rule may apply:The first rule is that the Transition timeout interval may be indicated by an AP (Affiliated AP) belonging to the AP MLD in the Transition Timeout subfield of the EML Capabilities subfield of the Basic Multi-Link element of all Management frames, including the Basic Multi-Link element, except for Authentication frames. The second rule is that the Transition timeout interval may start at the end of a PPDU [+SigExt (Signal Extension)] transmitted by an AP (Affiliated AP) belonging to the AP MLD that returns an Immediate Acknowledgement to an EML Operating Mode Notification frame transmitted by a Non-AP STA belonging to the Non-AP MLD. The third rule is that the EML Control field of an EML Operating Mode Notification frame transmitted by an AP (Affiliated AP) belonging to the AP MLD may be set to the same value as the EML Control field of the received EML Operating Mode Notification frame.

[0118] Regarding activation of the EMLSR SC mode, when a Non-AP MLD with Dot11EHTEMLSRSecondaryChannelAccessOptionActivated set to true enables the EMLSR SC mode on the EMLSR link, the Non-AP MLD may be considered to support EMLSR operation. Here, the Non-AP MLD may transmit an association request frame including information indicating that Secondary Channel Access Mode is enabled as capability information.

[0119] Regarding activation of the EMLSR SC mode, when a Non-AP MLD with Dot11EHTEMLSRSSecondaryChannelAccessOptionActivated set to true enables the EMLSR SC mode on the EMLSR link, the Non-AP MLD can operate the EMLSR mode on the EMLSR link, and therefore other Non-AP STAs belonging to the Non-AP MLD can also operate the EMLSR SC mode on the EMLSR SC link corresponding to the other Non-AP STAs. In this case, other Non-AP STAs belonging to the Non-AP MLD operating on the EMLSR SC link may transition to the active mode without transmitting an EML Operating Mode Notification frame or a frame with the Power Management subfield set to 0. This transition to Active mode may occur at the end of the Transition timeout interval, or immediately after transmitting an Acknowledgment in response to an EML Operating Mode Notification frame received from one of the APs (Affiliated APs) belonging to the AP MLD before the end of the Transition timeout interval, whichever occurs first. Furthermore, other Non-AP STAs operating on the EMLSR SC link may not transmit frames with the Power Management subfield set to 1 until they receive an EML Operating Mode Notification frame from one of the APs (Affiliated APs) belonging to the AP MLD or before the end of the transition timeout interval, whichever occurs first.

[0120] Regarding the activation of the EMLSR SC link, a Non-AP MLD may operate in EMLSR SC mode on a designated set of activated links between connected AP MLDs. The EMLSR SC link may be indicated by setting the bit position corresponding to the Link ID value of the EMLSR SC link to 1 in the EMLSR Link Bitmap subfield of the EML Control field of the EML Operating Mode Notification frame. When the EMLSR SC mode is activated in a Single Radio Non-AP MLD, a Non-AP STA belonging to the Non-AP MLD operating on a link whose bit position in the EMLSR Link Bitmap subfield is equal to 0 must be in the Doze state if another Non-AP STA belonging to the Non-AP MLD is already in the Awake state on one of the EMLSR SC links.

[0121] Regarding the frame exchange sequence for EMLSR SC operation, the structure of the MU-RTS trigger frame, which is an ICF, will be described. An MLD supporting EMLSR SC operation can include one or more User Info fields in the User Info List field of the MU-RTS trigger frame. For example, an AP MLD supporting EMLSR SC operation includes one or more User Info fields as an ICF in the MU-RTS trigger frame and transmits the MU-RTS trigger frame. The RU Allocation subfield of the one or more User Info fields may include information about secondary channels. The one or more User Info fields may be any of an HE variant User Info field, an EHT variant User Info field, and a UHR variant User Info field.

[0122] Information about secondary channels will now be described. The RU Allocation subfield of one or more User Info fields transmitted to a non-AP STA indicates whether the CTS frame is transmitted on at least one channel. The AP MLD assigns at least one User Info field of one or more User Info fields of the MU-RTS trigger frame to one non-AP MLD, and sets the index of the RU of the secondary channel in the RU allocation subfield of the User Info field assigned to the non-AP MLD. The non-AP MLD refers to the non-AP STAs belonging to the non-AP MLD. For example, the information about the secondary channel may be the index of the RU of the secondary channel, such as a secondary 20 MHz channel, a secondary 40 MHz channel, a secondary 80 MHz channel, a secondary 160 MHz channel, a secondary 80+80 MHz channel (HE only), a primary 20 MHz + secondary 20 MHz, a primary 40 MHz + secondary 40 MHz, a primary 80 MHz + secondary 80 MHz (HE only), a primary 160 MHz + secondary 80+80 MHz channel (HE only), a primary 160 MHz + secondary 160 MHz (EHT, UHR only), etc. For example, for the encoding of B7-B1 in the RU Allocation subfield, if the primary channel is 61, 62-64 and 70-81 are set to 20 MHz secondary, if the primary channel is 65, 66 and 82-87 are set to 40 MHz secondary, if the primary channel is 67, 88-90 are set to 80 MHz secondary, and if the primary channel is 68, 91 is set to 160 MHz secondary. The method for setting the index of the RU of the secondary channel is not limited to this. However, the value of the AID12 subfield in the User Info field in which the index of the RU of the secondary channel is set may be the same.

[0123] Regarding the frame exchange sequence for EMLSR SC operation, an example of a CTS frame in response to an MU-RTS trigger frame will be described. When a non-AP STA receives an MU-RTS trigger frame as an ICF, the transmission of the CTS frame shall start from the SIFS time boundary after the end of the received PPDU if the non-AP STA is operating in EMLSR SC mode and all of the following conditions are met: The first condition may be that the AID12 subfield of the User Info field in the MU-RTS trigger frame matches the 12 LSB of the AID of a non-AP STA belonging to the non-AP MLD; The second condition may be that the MU-RTS trigger frame is transmitted from an affiliated AP connected to the non-AP STA or an affiliated AP corresponding to the Transmitted BSSID. In the latter case, the non-AP STA may set the Rx Control Frame To MultiBSS subfield of the HE Capabilities element to 1 to indicate that it supports receiving control frames with the TA of the Transmitted BSSID. The third condition may be that, if there are multiple User Info fields, all AID12 subfields indicate the same AID. If these conditions are not met, the non-AP STA may not transmit a CTS frame. That is, if the value of the AID12 subfield in one or more User Info fields included in the MU-RTS trigger frame is an AID assigned to a non-AP MLD, the non-AP STA may select at least one index of an RU on a secondary channel from the RU allocation subfield in one or more User Info fields of the MU-RTS trigger frame, and transmit a CTS frame on the channel indicated by the selected index in response to receiving the MU-RTS trigger frame. Note that the non-AP MLD supports EMLSR operation.

[0124] Regarding the frame exchange sequence for EMLSR SC operation, the response of an EHT STA to an MU-RTS trigger frame in EMLSR SC mode will be described. The CTS frame transmitted in response to the MU-RTS trigger frame may be transmitted in the RU indicated in the RU Allocation subfield of the HE variant User Info field, EHT variant User Info field, or UHR variant User Info field. However, punctured 20 MHz subchannels indicated in the Disabled Subchannel Bitmap subfield of the EHT Operation element are excluded. The RU may be a channel indicated by the index selected in the RU Allocation subfield of the MU-RTS trigger frame. In response to the MU-RTS trigger frame, a non-AP STA transmits a CTS frame on the secondary channel indicated by the index selected in the RU Allocation subfield of the MU-RTS trigger frame. [2. Common to all embodiments]

[0125] A wireless communication device according to an embodiment of the present invention can communicate in a frequency band (frequency spectrum) called an unlicensed band, which does not require permission to use from a country or region, but the usable frequency band is not limited to this. The wireless communication device according to an embodiment of the present invention can also be effective in a frequency band called a white band (e.g., a frequency band allocated for television broadcasting but unused in some regions) that is not actually used despite permission to use it for a specific service from a country or region for the purpose of preventing interference between frequencies, or in a shared spectrum (shared frequency band) that is expected to be shared by multiple operators.

[0126] A program running on a wireless communication device according to one aspect of the present invention is a program (a program that causes a computer to function) that controls a CPU and other components to implement the functions of the above-described embodiment according to one aspect of the present invention. Information handled by these devices is temporarily stored in RAM during processing, and then stored in various ROMs or HDDs, where it is read, modified, and written by the CPU as needed. Recording media for storing the program may include semiconductor media (e.g., ROM, non-volatile memory cards, solid-state drives, etc.), optical recording media (e.g., DVDs, MOs, MDs, CDs, BDs, etc.), and magnetic recording media (e.g., magnetic tapes, flexible disks, etc.). Executing a loaded program not only implements the functions of the above-described embodiment, but may also implement the functions of the present invention by processing in cooperation with an operating system or other application programs based on instructions from the program.

[0127] Furthermore, when distributing the program on the market, the program can be stored and distributed on a portable recording medium or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer also falls within one aspect of the present invention. Furthermore, part or all of the wireless communication device in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit. Each functional block of the wireless communication device may be individually formed into a chip, or part or all of the functional blocks may be integrated into a chip. When each functional block is formed into an integrated circuit, an integrated circuit control unit that controls them is added. Needless to say, a case in which a program or setting information is downloaded from a server computer to implement at least part of the functions of the above-described embodiments also falls within one aspect of the present invention.

[0128] Furthermore, the method of integration is not limited to LSI, but may be realized by a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology, it may also be possible to use an integrated circuit based on that technology.

[0129] It should be noted that one aspect of the present invention is not limited to the above-described embodiment. The wireless communication device of the present invention is not limited to application to a mobile station device, but can of course be applied to stationary or non-mobile electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0130] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included in the scope of the claims.

[0131] One aspect of the present invention is suitable for use in a wireless communication device and a wireless communication method.

[0132] 1-1, 1-2 Access point device 2-1, 2-2, 2-3, 2-4, 3-1, 3-2, 3-3, 3-4 Station device 2-5, 3-5 Wireless communication system 10000-1 Wireless communication device 10001-1 Upper layer unit 10001a-1 MAC layer frame generation unit 10001b-1 Upper layer control unit 10002-1 Autonomous distributed control unit 10002a-1 CCA unit 10002b-1 Backoff unit 10002c-1 Transmission decision unit 10003-1 Transmission unit 10003a-1 Physical layer frame generation unit 10003b-1 Wireless transmission unit 10004-1 Reception unit 10004a-1 Wireless reception unit 10004b-1 Signal demodulation unit 10005-1 Antenna section 10-1 Beacon 10-2 Probe request 10-3 Probe response 10-4 Enhanced Multi-Link (EML) Operating Mode Notification frame 10-5, 11-11, 11-12, 11-13, 11-14 ICF 10-6, 11-21, 11-22, 11-23, 11-24 ICR 10-7, 11-31, 11-32, 11-33, 11-34 Frame 20000-1 MLD access point device 20000-2, 20000-3, 20000-4 Sub-access point device 30000-1 MLD station device 30000-2, 30000-3, 30000-4 Sub-station device

Claims

1. An access point device, wherein the access point device is an access point multilink device, comprising a transmitter and a controller, wherein the controller supports Enhanced Multi-Link Single Radio (EMLSR), wherein the controller further includes one or more User Info fields in the MU-RTS trigger frame, and assigns at least one of the one or more User Info fields to one Non-AP multilink device, and sets an index of an RU of a secondary channel in an RU allocation subfield of the User Info field assigned to the Non-AP multilink device, wherein the values ​​of the AID12 subfields of the User Info fields in which the index of the RU of the secondary channel is set are the same, and the transmitter further transmits the MU-RTS trigger frame as an initial control frame.

2. An access point device as described in claim 1, wherein the control unit includes a Basic Multi-Link element in a beacon or a probe response frame, includes first control information in the Basic Multi-Link element, and the first control information includes information indicating support for EMLSR Secondary Channel Access, and the transmission unit transmits the beacon or the probe response frame.

3. A station device, wherein the station device is a Non-AP multilink device, and comprises a transmitter, a controller, and a receiver, wherein the controller supports Enhanced Multi-Link Single Radio (EMLSR) and includes first control information in an Enhanced Multi-Link (EML) Control field of an Enhanced Multi-Link (EML) Operating Mode Notification frame, the first control information indicating that Secondary Channel Access Mode is enabled in the EMLSR, the transmitter transmits the Enhanced Multi-Link (EML) Operating Mode Notification frame, the receiver receives an MU-RTS trigger frame as an initial control frame, and the controller, when a value of an AID12 subfield of one or more User Info fields included in the MU-RTS trigger frame is an AID assigned to the Non-AP multilink device, selects at least one index of an RU of a secondary channel from an RU allocation subfield of one or more User Info fields of the MU-RTS trigger frame, The transmitter further transmits a CTS frame on the channel indicated by the selected index in response to receiving the MU-RTS trigger frame.

4. A station device according to claim 3, wherein the association request frame includes, as capability information, information indicating that Secondary Channel Access Mode is enabled in the EMLSR.

Images