Station device, access point device, and communication method

Abstract

To establish a method for appropriately controlling transition to an NPCA primary channel in order to improve wireless medium use efficiency.SOLUTION: According to the present invention, a lower layer unit determines transition to an NPCA primary channel based on information (an NAV threshold value, a bandwidth threshold value, a received power threshold value, and the like) indicating one or a plurality of values notified by an NPCA (Non-PrimaryChannelAccess) information element, and thus it is possible to improve effectiveness of substantial frequency use efficiency at the time of transition to the NPCA primary channel.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a station device, an access point device, and a communication method. [Background technology]

[0002] IEEE802.11be, which will achieve even faster speeds than the IEEE802.11 wireless LAN (Local Area Network) standard, is currently being standardized by the IEEE (The Institute of Electrical and Electronics Engineers Inc.), and wireless LAN devices compliant with the specification draft are appearing on the market. Currently, standardization activities for IEEE802.11bn, the successor to IEEE802.11be, have begun. The main theme in the standardization of IEEE802.11bn 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 a wireless LAN access point function 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 called an access point device) to the line termination device. In other words, wireless LAN station devices (also called station devices), such as smartphones and personal computers, can access the Internet by connecting to a wireless LAN access point device. When home wireless LANs were first introduced, homes often had only one wireless LAN access point device. However, these days, multiple wireless LAN access points are being installed to expand the coverage of the wireless LAN area within a home. For personal use, wireless LAN mesh networks, which enable wireless communication between wireless LAN access point devices (backhaul) via wireless LAN, are particularly popular for simplifying network construction. On the other hand, for enterprises, wired connections such as Ethernet (registered trademark) between wireless LAN access point devices are preferred to increase the reliability of frame transmission. However, because there is a trade-off between communication performance and the complexity of equipment installation, the decision of whether to use a wireless or wired connection between wireless LAN access point devices may be made based on the use case, taking into account the balance between these two factors.

[0004] Meanwhile, the United States has made it possible to use the 6 GHz band (5.925-7.125 GHz) as an unlicensed band, while Europe and Japan have approved the use of the lower frequencies of the 6 GHz band (5.925-6.425 GHz), with consideration underway for the upper frequencies (6.425-7.125 GHz). Similar considerations are also underway in other countries around the world. These trends are likely to enable wireless LANs 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.

[0005] The 6 GHz band is a frequency band between approximately 5.925 and 7.125 GHz, and a total of approximately 1.2 GHz of bandwidth will be newly available, which means that the equivalent of 14 80 MHz-wide channels and 7 160 MHz-wide channels will be added. Because of the availability of abundant frequency resources, the maximum channel bandwidth available for a single wireless LAN communication system (equivalent to BSS, described below) will double from 160 MHz in IEEE802.11ax to 320 MHz in IEEE802.11be.

[0006] While the 2.4 GHz band offers relatively wide coverage (the range in which communication is possible), it is subject to significant interference between communication devices and has a relatively narrow available bandwidth. The 5 GHz and 6 GHz bands offer wide communication bandwidths but lack coverage. Therefore, to realize various services and applications over WLAN, it is desirable to aggregate or switch between frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.) depending on the use case. However, devices using conventional WLAN communication standards were unable to aggregate and use different frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.) used for communication. Furthermore, switching between frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.) required disconnecting from the current frequency band and reconnecting to another frequency band.

[0007] 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. In other words, MLO allows a communication device to 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.

[0008] Furthermore, in the IEEE 802.11bn standardization, discussions are underway regarding Non-Primary Channel Access (NPCA) (Non-Patent Document 1). In conventional technologies, the maximum operating bandwidth is specified as wider as the generation becomes newer: 40 MHz for IEEE 802.11n, 80 MHz for IEEE 802.11ac, 160 MHz for IEEE 802.11ax, and 320 MHz for IEEE 802.11be. However, in practice, the bandwidth is divided into multiple 20 MHz subchannels for management. One 20 MHz subchannel must be designated as the primary channel, and a transmission opportunity (transmission right) must first be acquired for the primary channel. Then, a transmission opportunity must be acquired for a 20 MHz subchannel other than the primary channel. Therefore, if a transmission opportunity for the primary channel cannot be acquired, no transmission opportunity can be acquired even if multiple 20 MHz subchannels other than the primary channel are idle (unused). In the IEEE802.11be standard, if a transmission opportunity on the 20MHz primary channel cannot be acquired, the remaining 300MHz bandwidth cannot be used even if it is idle. The mechanism for acquiring transmission opportunities based on the primary channel is a remnant of the fact that WLAN technology was developed while maintaining backward compatibility. Wireless communication technologies that use the same frequency band as WLAN include Licensed Assisted Access (LAA), but they do not have channel access restrictions based on the primary channel like WLAN, putting WLAN technology at a disadvantage in terms of acquiring transmission opportunities. Therefore, a new channel access method is being considered for IEEE802.11bn, which would allow the use of multiple 20MHz subchannels other than the primary channel even if a transmission opportunity on the 20MHz primary channel cannot be acquired. [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] IEEE 802.11-24 / 0495-00-00bn, May.2024 Summary of the Invention [Problem to be solved by the invention]

[0010] NPCA is a technology in which, when the NAV is set to a 20 MHz primary channel and the channel is busy due to, for example, the occurrence of frame transmission / reception in an overlapping basic service set (OBSS), some or all wireless communication devices belonging to a basic service set (BSS) perform a channel transition (channel switch, channel change) to the NPCA primary channel, and if a transmission opportunity is obtained at the channel transition destination, wireless communication devices may transmit and receive frames. Here, the NPCA primary channel is a subchannel other than the primary channel that is included in the operation bandwidth (operation channel) of the wireless communication system. It is generally a 20 MHz subchannel, but may also be a subchannel with a larger bandwidth. Regardless of whether frames are transmitted or received on the NPCA primary channel, the wireless communication devices basically return to the primary channel before the end of the NAV set by the OBSS and attempt to obtain a transmission opportunity on the primary channel. To improve wireless medium utilization efficiency, it is necessary to establish a method for appropriately controlling the transition to the NPCA primary channel. [Means for solving the problem]

[0011] The communication device and communication method according to the present invention for solving the above-mentioned problems are as follows.

[0012] (1) That is, a station device according to one embodiment of the present invention comprises an upper layer section and a lower layer section, and the upper layer section determines that the lower layer section will transition to an NPCA primary channel based on information (first information) indicating one or more values ​​notified in an NPCA (Non-Primary Channel Access) information element.

[0013] (2) Also, a station device according to one embodiment of the present invention is described in (1) above, communicates with an access point device, and has a receiving unit, wherein the receiving unit receives a first frame transmitted by the access point device, and the first frame includes the NPCA information element.

[0014] (3) Also, a station device according to one embodiment of the present invention is described in (1) above, wherein the receiving unit receives a second frame from a wireless communication device other than a BSS (Basic Service Set) constituted by the access point device, and when at least one of the first information regarding the second frame satisfies a channel transition condition, the upper layer unit notifies the lower layer unit that a transition to the NPCA primary channel will be made.

[0015] (4) Furthermore, a station device according to one embodiment of the present invention is described in (1) above, wherein one of the first pieces of information is a NAV (Network Allocation Vector) threshold, and the channel transition condition is that the NAV set based on the second frame exceeds the NAV threshold.

[0016] (5) Furthermore, a station device according to one embodiment of the present invention is described in (1) above, wherein one of the first pieces of information is a bandwidth threshold, and the channel transition condition is that the bandwidth set based on the second frame is below the bandwidth threshold.

[0017] (6) Furthermore, a station device according to one aspect of the present invention is described in (1) above, wherein one of the first information is a reception power threshold, and the channel transition condition is that the reception power of the second frame is lower than the reception power threshold.

[0018] (7) Furthermore, an access point device according to one embodiment of the present invention is an access point device that communicates with one or more station devices, and is equipped with a transmitting unit, the transmitting unit transmits a frame to at least one of the one or more station devices, the frame including an NPCA information element, and the NPCA information element including information indicating an NPCA primary channel.

[0019] (8) Also, a station device according to one embodiment of the present invention is described in (7) above, wherein the NPCA information element includes information indicating one or more thresholds for channel transition conditions to the NPCA primary channel.

[0020] (9) Furthermore, a station device according to an aspect of the present invention is described in (7) above, wherein the threshold is a NAV threshold.

[0021] (10) Furthermore, a station device according to an aspect of the present invention is described in (7) above, wherein the threshold is a bandwidth threshold.

[0022] (11) Furthermore, a station device according to an aspect of the present invention is described in (7) above, wherein the threshold is a received power threshold.

[0023] (12) Also, a communication method according to one embodiment of the present invention is a communication method in a wireless communication system consisting of an access point device and one or more station devices, wherein the access point device transmits a frame including an NPCA information element to the station device, the NPCA information element including information indicating an NPCA primary channel and information indicating one or more thresholds for channel transition conditions to the NPCA primary channel, and the station device transitions to the NPCA primary channel when a frame received from a wireless communication device other than a BSS constituted by the access point device satisfies the channel transition conditions. [Effects of the Invention]

[0024] According to the present invention, in a wireless LAN communication system that supports NPCA (Non-Primary Channel Access), the effective frequency utilization efficiency during channel transition can be improved by analyzing frame transmission and reception in surrounding wireless LAN communication systems and determining whether or not to transition to the NPCA primary channel based on the characteristics of the frames. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 10 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention. [Figure 2] FIG. 10 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention. [Figure 3] 1 is a diagram illustrating an example of the architecture of a wireless communication device according to one aspect of the present invention. [Figure 4] 1 is a schematic diagram illustrating an example of division of a wireless medium according to one aspect of the present invention. [Figure 5] 1 is a diagram illustrating an example of a configuration of a communication system according to an aspect of the present invention. [Figure 6] 1 is a block diagram illustrating an example of a configuration of a wireless communication device according to an aspect of the present invention. [Figure 7] 1 is a block diagram illustrating an example of a configuration of a wireless communication device according to an aspect of the present invention. [Figure 8] 1 is a block diagram illustrating an example of a configuration of a wireless communication device according to an aspect of the present invention. [Figure 9] FIG. 10 is a diagram illustrating an example of a frame configuration according to an aspect of the present invention. [Figure 10] FIG. 1 is a diagram illustrating an example of a configuration of a frame sequence according to an aspect of the present invention. [Figure 11] FIG. 1 is a diagram illustrating an example of a configuration of a frame sequence according to an aspect of the present invention. [Figure 12] 1 is a diagram illustrating an example of a configuration of a communication system according to an aspect of the present invention. [Figure 13] FIG. 2 is a diagram illustrating an example of a frame sequence according to an aspect of the present invention. [Figure 14] FIG. 10 is a diagram showing an example of a Primitive sequence according to one embodiment of the present invention. [Figure 15] FIG. 10 is a diagram showing an example of a Primitive sequence according to one embodiment of the present invention. [Figure 16] FIG. 10 is a diagram showing an example of a Primitive sequence according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] The communication system in this embodiment includes an access point device (also referred to as a wireless base station device, base station device, AP (Access Point), etc.) and multiple station devices (also referred to as wireless terminal devices, terminal devices, non-AP STAs, etc.). A network configured from the access point device and the station devices is called a basic service set (BSS, management range). Hereinafter, when simply referring to a communication device or wireless communication device, it can refer to both the station devices and the access point devices.

[0027] 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 that form 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 station device that serves as a group owner and forms a group in Wi-Fi Direct can also be considered as an access point device.

[0028] Figure 3 shows the architecture of a wireless communication device (including an access point device and a station device). The MAC layer corresponds to the layer above the PHY layer. The MAC layer may also be called the upper layer, and the PHY layer the lower layer. The PHY layer includes a management entity called the PLME (Physical Layer Management Entity), and PHY layer management functions are invoked via the PLME. Similarly, the MAC layer includes a management entity called the MLME (Medium Access Control sublayer Management Entity), and MAC layer management functions are invoked via the MLME.

[0029] 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 layers such as PHY and MAC. 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. The MLME SAP Primitive, PLME SAP Primitive, MAC Service Primitive, PHY Service Primitive, etc. are collectively referred to as Primitives.

[0030] In the IEEE 802.11 system, each wireless communication device can transmit frames of multiple frame types with a common frame format. The frames are defined in the physical (PHY) layer, medium access control (MAC) layer, and logical link control (LLC) layer.

[0031] A frame at the PHY layer is called a physical protocol data unit (PPDU, also known as a 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, also known as a PHY service data unit, or MAC layer frame), which is the data unit processed at the physical layer. A PSDU can be composed of a MAC protocol data unit (MPDU), which is the unit of retransmission in the radio section, or an aggregated MPDU (A-MPDU), which aggregates multiple MAC protocol data units.

[0032] 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 supported standard, STFs are 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), and Extremely High Throughput-STF (EHT-STF). Similarly, LTFs and SIGs 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, assuming technical updates within the same standard, a Universal SIGNAL (U-SIG) field containing additional control information can be included.

[0033] 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, BSS Color) other than the SSID or MAC address.

[0034] The PPDU is modulated according to the corresponding standard, for example, DSSS (Direct Sequence Spread Spectrum) for IEEE 802.11b, or OFDM (Orthogonal Frequency Division Multiplexing) for IEEE 802.11a and its successors (IEEE 802.11g / n / ac / ax / be / bn, etc.).

[0035] A wireless communication device has either a function for transmitting PPDUs or a function for receiving PPDUs, or both. Fig. 1 shows an example of the structure of a PPDU transmitted by a wireless communication device. A PPDU conforming to the IEEE 802.11a / b / g standard includes an L-STF, an L-LTF, an L-SIG, and a Data frame (MAC Frame, MAC Frame, payload, data section, data, information bits, etc.). A High Throughput PPDU (HT PPDU) conforming to the IEEE 802.11n standard includes an L-STF, an L-LTF, an L-SIG, an HT-SIG, an HT-STF, an HT-LTF, and a Data frame. A Very High Throughput PPDU (VHT PPDU) conforming to the IEEE 802.11ac standard includes some or all of an L-STF, an L-LTF, an L-SIG, a VHT-SIG-A, a VHT-STF, a VHT-LTF, a VHT-SIG-B, and a MAC frame. The IEEE802.11ax standard compliant HE PPDU (High efficiency PPDU) is a structure that includes some or all of the L-STF, L-LTF, L-SIG, RL-SIG (which is a time-repeated L-SIG), HE-SIG-A, HE-STF, HE-LTF, HE-SIG-B, and Data frames. The IEEE802.11be standardized EHT PPDU (Extremely High Throughput PPDU) is a structure that includes some or all of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, HET-LTF, and Data frames.

[0036] 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 the data unit processed at the MAC layer, and a frame check sequence (FCS), which checks the frame for errors. The MAC header contains the Frame Control field, Duration / ID field, Address1 field, Address2 field, Address3 field, Sequence Control field, Address4 field, QoS Control field, HT Control field, Frame Body field, and FCS field. The Frame Control field identifies the frame type (e.g., management frame, control frame, data frame, extension frame, etc.). The Duration / ID field (which may simply be called the Duration field) contains a value corresponding to the length of the transmission opportunity. The Address1 field, Address2 field, Address3 field, Address4 field, etc. identify the frame's transmitter address (TA) and receiver address (RA).

[0037] The L-STF, L-LTF, and L-SIG in Fig. 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 L-headers). For example, a wireless communication device conforming to the IEEE 802.11a / b / g standard can properly receive an L-header in a PPDU conforming to the IEEE 802.11n / ac standard. A wireless communication device conforming to the IEEE 802.11a / b / g standard can receive a PPDU conforming to the IEEE 802.11n / ac standard, treating it as a PPDU conforming to the IEEE 802.11a / b / g standard.

[0038] 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 information contained in the MAC header regarding the transmitter address (TA), receiver address (RA), and the duration field used to set the network allocation vector (NAV).

[0039] 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 the L-SIG (RATE field, L-RATE field, L-RATE, L_DATARATE, L_DATARATE field) and information about the transmission duration (LENGTH field, L-LENGTH field, L-LENGTH) are used by wireless communication devices conforming to the IEEE 802.11a / b / g standards to appropriately set NAV.

[0040] 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.

[0041] A wireless communication device can transmit an L-SIG multiple times (L-SIG Repetition). For example, a receiving wireless communication device can receive the L-SIG transmitted multiple times using Maximum Ratio Combining (MRC), thereby improving the demodulation accuracy of the L-SIG. Furthermore, when the wireless communication device has successfully received the L-SIG using MRC, it can interpret the PPDU including the L-SIG as a PPDU that complies with the IEEE 802.11ax standard.

[0042] Even while receiving a PPDU, the wireless communication device can receive 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 PPDU reception operation, the wireless communication device can update some or all of the destination address, source address, and information related to the PPDU or DATA period.

[0043] 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 of these 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 ascertain the frame type and subframe type of a received frame by reading the contents of the Frame Control field included in the MAC header.

[0044] 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 in Figure 2), and an inspection field, and is called a management frame.

[0045] The Ack may include a Block Ack, which can be used to notify completion of reception of multiple MPDUs.

[0046] A beacon frame includes a beacon interval, a field describing the SSID, an information element, and so on. 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.

[0047] After recognizing an access point device, a station device performs a connection process with the access point device. The connection process is divided 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 to be authenticated by the access point device. Note that the access point device and station device can exchange authentication frames multiple times.

[0048] 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.

[0049] After the connection process is completed, the access point device and station device actually send and receive frames (also called frame exchange). The IEEE802.11 system defines a distributed coordination function (DCF: Distributed Coordination Function), a centralized coordination function (PCF: Point Coordination Function), and their extended functions (enhanced distributed channel access (EDCA) and hybrid coordination function (HCF)). The following describes an example in which an access point device sends a frame to a station device using DCF.

[0050] 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 frame transmission 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. This CS, which each wireless communication device performs 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 CCA threshold (CCAT). If the access point device or station device detects a signal higher than the CCA level, it begins demodulating at least the PHY layer signal.

[0051] An access point device performs carrier sensing at an interframe space (IFS) that corresponds to the type of frame being transmitted, to determine 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 it is about to transmit. The IEEE 802.11 system defines several 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.

[0052] 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 transmitted by a transmitting station is received by a wireless communication device (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 them 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). Note that if the access point device determines through carrier sense that the wireless channel is busy during the backoff counter countdown, it stops counting down the backoff counter. Then, when the wireless channel becomes idle, the access point device waits for the same period (DIFS) as the previous IFS, and then restarts counting down the remaining backoff counter.

[0053] 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: Group ID) written in the VHT-SIG-A).

[0054] If a station device determines that a received frame is addressed to its own wireless communication device and successfully demodulates the frame, it must transmit an Ack frame to the access point device, which is the transmitting station, indicating that the frame was received correctly. An Ack frame is one of the highest-priority frames that is transmitted after waiting an SIFS period without a random backoff time. When the access point device receives an Ack frame from the station device, the frame exchange is successfully completed. If the station device fails to receive the frame correctly, it 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. Thus, 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.

[0055] If 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. 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 based on 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. For frames corresponding to HE PPDUs, 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.

[0056] 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.

[0057] The communication period by PCF includes a contention-free period (CFP) and a contention period (CP). During the CP, communication is performed based on the DCF described above, and during the CFP, the PC controls the transmission opportunity. The access point device, which is the PC, broadcasts a beacon frame describing the CFP duration (CFP Max duration) and other information within the BSS prior to PCF communication. Note that 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 this 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.

[0058] A wireless medium can be divided into multiple resource units (RUs). FIG. 4 is a schematic diagram showing an example of how the wireless medium is divided. For example, in resource division example 1, a wireless communication device can divide frequency resources (subcarriers) of the wireless medium into nine RUs. Similarly, in resource division example 2, a wireless communication device can divide subcarriers of the wireless medium into five RUs. Of course, the resource division example shown in FIG. 4 is merely an example, and 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 state 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.

[0059] Furthermore, multiple wireless communication devices (e.g., multiple station devices) can transmit frames simultaneously by placing frames in the RUs assigned to them. After receiving a frame (Trigger frame: TF) containing trigger information transmitted from an access point device, multiple station devices can wait a predetermined period of time before transmitting a frame. Each station device can determine the RU assigned to itself based on the information contained in the TF. Furthermore, each station device can acquire an RU by random access based on the TF.

[0060] The access point device can simultaneously allocate multiple RUs to one station device. The multiple RUs can be configured with contiguous or non-contiguous 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 that transmit resource allocation information.

[0061] A station device can be assigned multiple RUs by the access point device. The station device can transmit a single frame using the assigned multiple RUs. The station device can also use the assigned multiple RUs to transmit multiple frames, each assigned to a different RU. The multiple frames can be of different frame types.

[0062] The access point device can assign multiple AIDs to one station device. The access point device can assign RUs to each of the multiple AIDs assigned to one station device. The access point device can transmit different frames to each of the multiple AIDs assigned to one station device using the assigned RUs. The different frames can be of different frame types.

[0063] A single station device can be assigned multiple AIDs by an access point device. A single station device can be assigned RUs for each of the multiple assigned AIDs. A single station device recognizes all RUs assigned to the multiple AIDs assigned to its own wireless communication device as RUs assigned to its own wireless communication device, and can transmit a single frame using the multiple assigned RUs. Furthermore, a single station device can transmit multiple frames using the multiple assigned RUs. At this time, the multiple frames can be transmitted by including information indicating the AIDs associated with the assigned RUs.

[0064] [1. First embodiment]

[0065] The wireless communication system of this embodiment will be described with reference to Fig. 5. Wireless communication system 3-1 (also referred to as BSS 3-1) includes access point device 1-1 and station devices 2-1, 2-12, 2-13, and 2-123. Station devices 2-1, 2-12, 2-13, and 2-123 are also collectively referred to as station device 2A (terminal device 2A) as station devices connected (associated) with access point device 1-1. 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.

[0066] The wireless communication system 3-2 (also referred to as BSS3-2) includes an access point device 1-2 and station devices 2-2, 2-21, 2-23, and 2-213. The station devices 2-2, 2-21, 2-23, and 2-213 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 can transmit and receive frames to and from each other.

[0067] The wireless communication system 3-3 (also referred to as BSS3-3) includes an access point device 1-3 and station devices 2-3, 2-31, 2-32, 2-34, and 2-312. The station devices 2-3, 2-31, 2-32, 2-34, and 2-312 are collectively referred to as station device 2C (terminal device 2C) as devices connected (associated) with the access point device 1-3. The access point device 1-3 and station device 2C are wirelessly connected and are capable of transmitting and receiving frames to and from each other.

[0068] The wireless communication system 3-4 (also referred to as BSS3-4) includes an access point device 1-4 and a station device 2-4. The station device 2-4 is also collectively referred to as a station device 2D (terminal device 2D) as a device connected to the access point device 1-4. The access point device 1-4 and the station device 2D are wirelessly connected and can transmit and receive frames to and from each other. The station device 2-4 transmits and receives frames only to and from the access point device 1-4, to which it is connected.

[0069] 5, the access point 1-1 is located within the coverage of the wireless communication system 3-2 of the access point 1-2 and within the coverage of the wireless communication system 3-3 of the access point 1-3, but outside the coverage of the wireless communication system 3-4 of the access point 1-4. Similarly, the access point 1-2 is located within the coverage of the wireless communication system 3-1 of the access point 1-1 and within the coverage of the wireless communication system 3-3 of the access point 1-3, but outside the coverage of the wireless communication system 3-4 of the access point 1-4. Similarly, the access point 1-3 is located within the coverage of the wireless communication system 3-1 of the access point 1-1 and within the coverage of the wireless communication system 3-2 of the access point 1-2, but outside the coverage of the wireless communication system 3-4 of the access point 1-4. On the other hand, access point 1-4 is located within the coverage of wireless communication system 3-3 of access point 1-3, but outside the coverage of wireless communication system 3-1 of access point 1-1 and outside the coverage of wireless communication system 3-2 of access point 1-2. Therefore, access point devices 1-1, 1-2, and 1-3 can transmit and receive wireless frames to and from each other, but access point 1-4 can transmit and receive wireless frames only to access point device 1-3.

[0070] Although the wireless communication systems 3-1, 3-2, 3-3, and 3-4 form different BSSs, this does not necessarily mean that the ESSs (Extended Service Sets) are different. An ESS indicates 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. The BSSs are connected via a DS (Distribution System) to form an ESS. Each of the wireless communication systems 3-1, 3-2, 3-3, and 3-4 can also be equipped with multiple wireless communication devices.

[0071] 6 is a diagram showing an example of the device configuration of wireless communication devices 1-1, 1-2, 1-3, 1-4, 2A, 2B, 2C, and 2D (hereinafter collectively referred to as wireless communication device 10000-1). Wireless communication device 10000-1 includes 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.

[0072] The upper layer unit 10001-1 includes 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 MAC layer frame generation unit 10001a-1 adjusts the information bits to a size that fits into the Framebody 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. The upper layer control unit 10001b-1 controls not only the upper layer unit 10001-1 itself but also controls communication with the DS and communication with the physical layer. For example, it may control whether to transmit the MAC frame to the DS or to the physical layer side (the autonomous distributed control unit 10002-1 and physical layer frame generation unit 10003a-1, which will be described later).

[0073] Upper layer unit 10001-1 has a MAC layer function, is connected to other networks and other BSSs via a DS (Distribution System), and can notify autonomous distributed control unit 10002-1 of traffic information. The traffic information may be, for example, information addressed to other wireless communication devices, or control information included in management frames or control frames. Upper layer unit 10001-1 may have an MLME function.

[0074] 7 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 includes a CCA unit (CCA step) 10002a-1, a backoff unit (backoff step) 10002b-1, and a transmission determination unit (transmission determination step) 10002c-1.

[0075] The CCA unit 10002a-1 can determine the state of the radio resource (including determining whether it is busy or idle) using either or both of information about the power of a signal received via the radio resource and information about 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 state determination information about the radio resource.

[0076] 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.

[0077] The transmission decision unit 10002c-1 makes a transmission decision using either or both of the wireless resource status decision information and the back-off counter value. 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 10002c-1 can notify the transmission decision information to the transmitting unit 10003-1.

[0078] The transmitting unit 10003-1 includes a physical layer frame generating unit (physical layer frame generating step) 10003a-1 and a radio transmitting unit (radio transmitting step) 10003b-1. The physical layer frame generating unit 10003a-1 has a 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 radio transmitting unit 10003b-1.

[0079] 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 unit. 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 configuring the coding blocks, dummy bits can also be inserted into the information bit sequence input from the MAC layer.

[0080] 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. The frames generated by the physical layer frame generator 10003a-1 also 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 that the wireless communication device instructed to transmit the frame will use when transmitting the frame.

[0081] The wireless transmitter 10003b-1 converts the physical layer frame generated by the physical layer frame generator 10003a-1 into a radio frequency (RF) band signal to generate a radio frequency signal. The processing performed by the wireless transmitter 10003b-1 includes digital-to-analog conversion, filtering, frequency conversion from the baseband to the RF band, etc.

[0082] The receiving unit 10004-1 includes a wireless receiving unit (wireless receiving step) 10004a-1 and a signal demodulating unit (signal demodulating step) 10004b-1. The receiving unit 10004-1 generates information related to received signal power from an RF band signal received by the antenna unit 10005-1. The receiving unit 10004-1 can notify the CCA unit 10002a-1 of the information related to the received signal power and the information related to the received signal.

[0083] The wireless receiver 10004a-1 has the function of converting an RF signal received by the antenna 10005-1 into a baseband signal and generating a physical layer signal (e.g., a physical layer frame). The processing performed by the wireless receiver 10004a-1 includes frequency conversion from the RF band to the baseband, filtering, and analog-to-digital conversion.

[0084] 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, and the like. The signal demodulation unit 10004b-1 can extract, from the physical layer signal, for example, information contained in the physical layer header, information contained in the MAC header, and other information contained in the MAC frame. The signal demodulation unit 10004b-1 can output the extracted information to the upper layer unit 10001-1. 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.

[0085] Antenna unit 10005-1 has a function of transmitting the radio frequency signal generated by radio transmission unit 10003b-1 into wireless space toward other radio device 10000-1, and also has a function of receiving the radio frequency signal transmitted from other radio device 10000-1.

[0086] The wireless communication device 10000-1 can include information indicating a 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 a frame to be transmitted, thereby causing wireless communication devices around 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 around the wireless communication device is referred to as the transmission opportunity (or TXOP period, or simply TXOP) acquired by the wireless communication device 10000-1. The wireless communication device 10000-1 that acquired the transmission opportunity is referred to as the TXOP acquirer (TXOP holder). The frame type of the frame transmitted by wireless communication device 10000-1 to notify it of 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, a CTS-to-self frame, etc.) or a data frame transmitted in a format such as Non-HT PPDU, HT PPDU, VHT PPDU, EHT PPDU, or UHR-PPDU.

[0087] The wireless communication device 10000-1, which is a TXOP holder, can transmit frames to wireless communication devices other than 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.

[0088] The wireless communication device 1-1 may acquire a transmission opportunity for all communication bands (operation bandwidth, operation channel, etc.) in which frames may be transmitted and received, 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.

[0089] The wireless communication device to which the wireless communication device 1-1 instructs to transmit and receive frames during 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 an RTS / CTS frame, and data frames.

[0090] This section also discusses transmission opportunities in EDCA, a channel access method (data transmission method) different from DCF. The IEEE 802.11e standard, which is related to EDCA, specifies transmission opportunities from the perspective of quality of service (QoS) guarantees 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 a set of EDCA parameters: the minimum CW (CWmin), the maximum CWmax, the length of the Arbitration IFS (AIFS), a type of IFS, and the TXOP limit, which is the upper limit of transmission opportunities. These parameters are set to differentiate between access categories. For example, the CWmin, CWmax, and AIFS for VO, which has the highest priority for voice transmission, can be set to relatively small values ​​compared to other access categories, enabling data transmission to take priority over other access categories. For example, in VI, where the amount of data transmitted is relatively large for video transmission, setting a large TXOP limit makes it possible to secure longer transmission opportunities than in other access categories.In this way, the EDCA parameter values ​​for each access category are adjusted to guarantee QoS according to the type of service.

[0091] In this embodiment, 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, the error detection includes error detection using an error detection code (e.g., a cyclic redundancy check (CRC) code) that is previously 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 (LDPC) code). The decoding processing at the physical layer can be applied to each coding block.

[0092] 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 to determine whether the MAC layer signal transmitted by the station device that transmitted the received frame was correctly decoded.

[0093] The wireless communication device may be a multi-link device (MLD) capable of multi-link communication. An access point device that supports MLD is called an MLD access point device, and a station device that supports MLD is called an MLD station device. Furthermore, MLD access point devices and MLD station devices are collectively called MLD wireless communication devices.

[0094] The MLD access point device 20000-1 and MLD station device 30000-1 will be described using Figure 8. An 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 called a physical layer link) that constitutes a multilink. Figure 8 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 8 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. The sub-wireless communication device (sub-access point device, sub-station device, etc.) may be configured as a 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).

[0095] In Fig. 8, 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 is the same as that described above with reference to Figs. 6 and 7.

[0096] The number of sub-access point devices included in one MLD access point device and the number of substation devices included in one MLD station device may vary depending on the grade, class, and capabilities of each MLD wireless communication device. The higher the grade, class, and capabilities of an MLD wireless communication device, the more sub-wireless communication devices (sub-access point devices, substation devices) it may have. 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) that make up each MLD wireless communication device may vary depending on the grade, class, and capabilities, and these numbers do not have to be the same.

[0097] The substation apparatus 30000-2 connects (associates) with the sub-access point apparatus 20000-2 and establishes link 1. The substation apparatus 30000-3 connects (associates) with the sub-access point apparatus 20000-3 and establishes link 2. The substation apparatus 30000-4 connects (associates) with the sub-access point apparatus 20000-4 and establishes link 3. In the description of this embodiment, the number of links constituting the multilink is three, but this is not limited to three and any number may be used. In the description of this embodiment, the carrier frequency of link 1 is the 2.4 GHz band, the carrier frequency of link 2 is the 5 GHz band, and the carrier frequency of link 3 is the 6 GHz band. However, the frequency used by each link can be set arbitrarily from the 2.4 GHz band, 5 GHz band, 6 GHz band, 60 GHz band, or any other frequency band, channel, or subchannel supported by the wireless communication system, and may vary depending on the laws and regulations of each country.

[0098] Here, with reference to FIG. 11, it will be further explained that the acquisition of transmission opportunities is performed for each 20 MHz bandwidth in channel access in an IEEE 802.11 system. For example, assume that a wireless communication system is constructed using an access point device conforming to IEEE 802.11ax, with a total operational bandwidth of 80 MHz, consisting of subchannels CH1 to CH4, each with a 20 MHz bandwidth. One of CH1 to CH4 is set as the primary channel. For example, when CH1 is set as the primary channel, CH2 adjacent to CH1 is called the secondary channel, the combination of CH1 and CH2 is called the 40 MHz primary channel, and the combination of CH3 and CH4 adjacent to the 40 MHz primary channel is called the 40 MHz secondary channel. Note that the acquisition of transmission opportunities based on counting the backoff time and carrier sense in the primary channel also affects the acquisition of transmission opportunities in other channels.

[0099] Assuming that the primary channel is set to CH1, an example of a frame transmission procedure will be described below in which station device 2-1 transmits a frame to access point device 1-1. If station device 2-1 performs carrier sensing on CH1 after a random backoff time and determines that CH1 is in an idle state, it may transmit an RTS frame 11-11 on CH1. If CH1, the primary channel, is in an idle state, it may also perform carrier sensing on the remaining CH2 to CH4, and if it confirms that they are in an idle state, it may transmit RTS frames 11-12 to 11-14. Note that if primary channel CH1 is in a busy state, it does not proceed to the procedure of carrier sensing on the other channels CH2 to CH4. Upon receiving the RTS frame, access point device 1-1 checks the wireless channel conditions of CH1 to CH4 and, if it determines that they are in an idle state, transmits CTS frames 11-21 to 11-24 indicating this on each of CH1 to CH4, which are received by station device 2-1. The station device may determine that the radio channels CH1 to CH4 are available for use and transmit data frames 11-31 to 11-34, that is, the data frames can be transmitted using the entire 80 MHz channel bandwidth.

[0100] On the other hand, even if station device 2-1 transmits an RTS frame, there are cases where the CTS frame cannot be received on some of CH1 to CH4. For example, when access point device 1-1 receives RTS frames 11-41 to 11-44 on CH1 to CH4, respectively, it checks the wireless channel conditions and determines that only CH3 and CH4 are idle, and transmits CTS frames (11-53, 11-54) only to CH3 and CH4. If station device 2-1 cannot receive a CTS frame on CH1, which is the primary channel, it cannot transmit a data frame on any of CH1 to CH4. In other words, the decision on whether to transmit a data frame depends on the condition of the primary channel.

[0101] As another example, there may be a case where a CTS frame is received on CH1, which is the primary channel, but the CTS frame cannot be received on any of CH1 to CH4. For example, an access point device that receives RTS frames 11-61 to 11-64 on each of CH1 to CH4 checks the wireless channel conditions and determines that only CH1 and CH2 are idle, and transmits CTS frames (11-71, 11-72) only to CH1 and CH2. Although station device 2-1 is able to transmit data frames because it received the CTS frame on CH1, which is the primary channel, it detects that only CH1 and CH2 are idle, and transmits data frames 11-81 and 11-82. In other words, station device 2-1 can only use a 40 MHz bandwidth out of the 80 MHz bandwidth.

[0102] The access point device may write information indicating the primary channel set in the wireless communication system it configures in an OCI (Operating Channel Information) information element or the like. The access point device includes the OCI information element in management frames such as beacons and probe responses and transmits them to the station device. The station device can identify the primary channel from the contents of the OCI information element included in the received management frame. The access point device may write information indicating the primary channel in an information element other than the OCI information element, include it in the management frame, and transmit it to the station device.

[0103] An overview of Non-Primary Channel Access (NPCA) will be described. First, in the conventional channel access method, as explained above with reference to FIG. 11, when the operating bandwidth is composed of multiple 20 MHz subchannels, if a transmission opportunity (transmission right) is acquired in the 20 MHz subchannel set as the primary channel, the step of determining whether the remaining subchannels are available for use can be proceeded to. In other words, if a transmission opportunity cannot be acquired in the 20 MHz subchannel set as the primary channel, the remaining subchannels cannot be used either. NPCA is a technology that improves frequency utilization efficiency by allowing channel access that can acquire transmission opportunities in subchannels other than the primary channel without acquiring a transmission opportunity in the primary channel, which was required in the conventional technology. Specifically, even if a transmission opportunity in the primary channel cannot be acquired, if a transmission opportunity in the NPCA primary channel (also referred to as the NPCA primary channel or the secondary primary channel) is attempted and acquired, the system allows frame transmission, including in other idle subchannels. From the perspective of channel access, the NPCA primary channel can be said to play a role equivalent to that of the primary channel.

[0104] NPCA is a technology in which, when the NAV is set to the 20 MHz primary channel and the channel is busy due to, for example, the occurrence of OBSS frame transmission / reception, some or all of the wireless communication devices belonging to the BSS perform a channel transition (channel switch) to the NPCA primary channel, and if a transmission opportunity is obtained at the channel transition destination, frames may be transmitted and received between the wireless communication devices. Here, the NPCA primary channel is a subchannel other than the primary channel that is included in the operation bandwidth (operation channel) of the wireless communication system. It is generally a 20 MHz subchannel, but may be a subchannel with a larger bandwidth. Regardless of whether frames are transmitted and received on the NPCA primary channel, the wireless communication devices basically return to the primary channel before the NAV set by the OBSS expires and attempt to obtain a transmission opportunity on the primary channel. If medium access recovery processing is permitted, the wireless communication devices may return to the primary channel after the NAV set by the OBSS expires. Note that frames transmitted via OBSS are referred to as OBSS frames.

[0105] The procedure for establishing NPCA (also referred to as a configuration procedure) according to this embodiment will now be described. The access point device may store information related to NPCA in an NPCA information element and transmit it via management frames such as beacons and probe responses. FIG. 9 shows an example of the configuration of an NPCA information element. The NPCA information element includes a field indicating at least one NPCA primary channel (NPCA primary channel, secondary primary channel), but may also include fields indicating other NPCA primary channel candidates. As mentioned above, channels (frequencies) in a wireless LAN are basically handled in 20 MHz subchannel units, and the NPCA primary channel field may contain a channel number assigned in 20 MHz units. The NPCA primary channel may be 20 MHz wide or wider. For example, if the NPCA primary channel is 40 MHz wide, a channel number corresponding to that may be described.

[0106] The NPCA information element may include a field indicating the NPCA maximum bandwidth, which indicates the maximum bandwidth that may be used for transmitting and receiving frames when a transmission opportunity is acquired on the NPCA primary channel.

[0107] The NPCA primary channel and the NPCA maximum bandwidth may be dynamically changed or may be set statically. The NPCA primary channel and the NPCA maximum bandwidth may be determined based on statistical information generated by monitoring wireless frames transmitted and received in BSSs surrounding the BSS, such as the bandwidth occupancy status, frame transmission and reception frequency, and received power in the BSS. In this case, information obtained by the access point device via other station devices using functions such as neighbor reporting and beacon reporting may be used. The NPCA primary channel may be set to a channel separated from the primary channel by a predetermined minimum separation bandwidth (also referred to as the minimum separation channel or the minimum number of separation channels). The minimum separation bandwidth may be determined in advance using a Management Information Base (MIB) or the like. In the 6 GHz band, channel numbers 5, 21, 37, 53, 59, 69, 85, 101, 117, 133, 149, 165, 181, 197, 213, and 229 are designated as PSCs (Preferred Scanning Channels) to reduce the number of scanned channels, and the NPCA primary channel may be selected from the PSCs.

[0108] The NPCA information element may include a field indicating an NPCA execution threshold, which indicates a condition value for transitioning to the NPCA primary channel. Examples of NPCA execution thresholds include the NPCA NAV threshold, the NPCA bandwidth threshold, and the NPCA receive power threshold. The purpose of setting these values ​​is to prevent unconditional transitions to the NPCA primary channel and improve the effectiveness of actual spectral efficiency when transitioning to the NPCA primary channel. Therefore, if this purpose can be achieved, condition values ​​other than the three types described above may be adopted and described in the NPCA execution threshold field of the NPCA information element. The NPCA information element may include at least one condition value from the NPCA NAV threshold, the NPCA bandwidth threshold, the NPCA receive power threshold, and other thresholds, or may include multiple condition values. Furthermore, the NPCA execution threshold field does not necessarily have to be a threshold value; it may also include a value, an index value, or a range. These condition values ​​may be managed by the MIB. In addition, the content described above as being written in the NPCA execution threshold field does not necessarily have to be notified by the access point device, but may be a value specified by the standard and commonly used by wireless communication devices that comply with the standard.

[0109] The NPCA information element may include an NPCA enable / disable field that indicates whether NPCA is enabled or disabled at the time the management frame containing the NPCA information element is transmitted. The access point devices that make up the BSS monitor wireless frames transmitted and received in surrounding BSSs and can enable or disable NPCA based on the bandwidth occupancy status, frame transmission / reception frequency, and reception power in the BSS. If the NPCA enable / disable field indicates NPCA disabled, wireless communication devices included in the BSS do not perform NPCA. If the NPCA enable / disable field indicates NPCA enabled, wireless communication devices included in the BSS may perform NPCA.

[0110] In this embodiment, a negotiation procedure, which is a preliminary preparation for performing NPCA, will be described using the sequence diagram of FIG. 10. While FIG. 10 illustrates station device 2-1 as an example, it may be any station device included in station device 2A. Station device 2-1 intending to perform NPCA may transmit an NPCA participation request frame (10-1) to access point device 1-1. The NPCA participation request frame may include capability information of the station device. Examples of the capability information may include the delay time required to transition between the primary channel and the NPCA primary channel (channel transition delay time), as well as information on characteristics specific to the NPCA primary channel (maximum channel bandwidth, maximum operating bandwidth, maximum bandwidth, maximum MCS (Modulation and Coding Scheme), maximum number of streams, maximum transmit power, receiver sensitivity, etc.).

[0111] The access point device 1-1 transmits an NPCA participation response frame (10-2) to the station device 2-1. The NPCA participation response frame (10-2) includes at least status information indicating whether the station device 2-1 is to "permit (success, accept)" or "reject (fail)" the NPCA. The access point device 1-1 may determine the content of the status information in accordance with the NPCA permission conditions. The NPCA permission conditions may be managed by an MIB or the like.

[0112] The access point device 1-1 may determine whether to "permit (success, accept)" or "reject (fail)" the NPCA for the station device 2-1 based on the capability information of the station device included in the NPCA participation request frame (10-1). For example, a channel transition delay time upper limit may be set in an MIB or the like, and the NPCA permission condition (also referred to as an NPCA participation condition or NPCA acceptance condition) may be that the channel transition delay time of the station device is shorter than the channel transition delay time upper limit ("less than or equal to (≦)" or "less than (<)")). If the channel transition delay time of the station device is longer than the channel transition delay time upper limit ("exceeds (>)" or "greater than or equal to (≧)"), it may determine that the efficiency of NPCA in the entire wireless communication system may be reduced, and may "reject (fail)" the NPCA participation request of the station device.

[0113] Alternatively, the access point device may determine whether to "permit (succeed, accept)" or "reject (fail)" NPCA for the station device, without basing it on the capability information of the station device included in the NPCA participation request frame (10-1). For example, the maximum number of NPCA-enabled station devices that the access point device can manage (the upper limit of the number of NPCA station devices) may be set in an MIB or the like, and the NPCA permission condition (also referred to as an NPCA participation condition or NPCA acceptance condition) may be that the number of NPCA-permitted stations is kept less than the maximum number of NPCA station devices ("less than or equal to (≦)" or "less than (<)")). If permitting NPCA for the station device would exceed the maximum number of NPCA station devices ("exceed (>)" or "greater than or equal to (≧)"), the access point device may determine that the efficiency of NPCA in the entire wireless communication system may be reduced, and may "reject (fail)" the NPCA participation request for the station device.

[0114] The NPCA permission conditions are not limited to the conditions based on the upper limit of the channel transition delay time and the maximum number of NPCA station devices described above, but may be any conditions that can limit the station devices that are capable of NPCA within the BSS managed by the access point device.

[0115] The access point device 1-1 can adjust and limit the number of station devices that perform NPCA by notifying "permission (success, accepted)" or "rejection (failure)" in the status information of the NPCA participation response frame (10-2). One reason for imposing such a limit is that as the number of station devices participating in NPCA increases, the competition for medium acquisition among the station devices increases after the NPCA primary channel transition, which can result in poor efficiency. However, a station device that is notified of "permission (success, accepted)" in the status information of the NPCA participation response frame (10-2) does not necessarily have to perform NPCA.

[0116] There are at least two methods for enabling the NPCA operation of the station device 2-1. In method 1, the access point device 1-1 may "enable (valid, possible)" the NPCA operation of the station device 2-1 by notifying "permission (success, acceptance)" in the status information of the NPCA participation response frame (10-2). In method 2, the access point device 1-1 may "enable (valid, possible)" the NPCA operation of the station device 2-1 by transmitting an NPCA enable frame (10-3) in addition to "enable (valid, possible)" in the status information of the NPCA participation response frame (10-2). The access point device 1-1 may "disable (not possible)" the NPCA operation of the station device 2-1 by transmitting an NPCA disable frame (10-4). The access point device 1-1 may notify the NPCA enable frame (10-3) or the NPCA disable frame (10-4) by broadcast frames or individually by unicast frames. By broadcasting NPCA enable / disable frames to station devices, NPCA can be enabled / disabled collectively throughout the entire wireless communication system. By individually sending NPCA enable / disable frames to station devices, the number of station devices participating in NPCA can be flexibly controlled and adjusted. Access point devices can decide whether to select Method 1 or Method 2 through settings in the MIB, etc., depending on operational policies, etc.

[0117] The NPCA join response frame, NPCA valid frame, NPCA invalid frame, etc. may be management frames (action frames, etc.). The NPCA join request may be included in an association request transmitted by the station device 2-1 when connecting to the access point device 1-1, and the NPCA join response may be included in an association response transmitted by the access point device 1-1 to the station device 2-1.

[0118] The station device 2-1 may unilaterally notify the access point device 1-1 that it will stop executing NPCA by transmitting an NPCA withdrawal request frame (10-5) to the access point device 1-1. Alternatively, the station device 2-1 may check the value of the status information (such as "permitted (success, accepted)" or "rejected (failed)") contained in the NPCA withdrawal response frame (10-6) transmitted from the access point device 1-1, and if the value is "permitted (success, accepted)," may cancel the execution of NPCA.

[0119] The NPCA withdrawal request frame and the NPCA withdrawal response frame may be management frames (such as action frames). The NPCA withdrawal request may be included in a disassociation frame or a deauthentication frame that the station device 2-1 transmits when disconnecting from the access point device 1-1.

[0120] An example of the operation of NPCA (Non-Primary Channel Access) in this embodiment will be described with reference to FIG. 12. It is assumed that NPCA has been enabled for the access point device 1-1 and the station device 2-1 through the negotiation procedure described in FIG. 10. It is assumed that the wireless communication system 3-1 (BSS1) and the wireless communication system 3-2 (BSS2), whose wireless communication coverage overlaps with BSS1, both use the 20 MHz subchannel CH1 as their primary channel. It is also assumed that CH4 is set as the NPCA primary channel. When considering BSS1 as the center, BSS2, whose wireless coverage overlaps, is the BSS configured by access point device 1-2, which is a wireless communication device other than BSS1 configured by access point device 1-1. BSS2 is referred to as an OBSS (Overlapping BSS), and frames transmitted and received in BSS2 are referred to as OBSS frames. Similarly, when considering BSS2 as the center, BSS1 is the OBSS, and frames transmitted and received in BSS1 are OBSS frames. In the example of Fig. 12, the behavior of NPCA will be explained mainly with respect to BSS1, BSS2 will be referred to as OBSS, and frame transmission and reception within BSS1 will be referred to as BSS frames, and frame transmission and reception within BSS2 will be referred to as OBSS frames. Also, for the sake of simplicity, only one station device 2-1 is shown in Fig. 12, but multiple station devices 2A may exist.

[0121] When an access point device 1-2 constituting an OBSS that has obtained a transmission opportunity on primary channel CH1 decides to transmit and receive wireless frames only on the 20 MHz bandwidth of CH1 out of the 80 MHz bandwidth of CH1 to CH4, it transmits an RTS frame 12-21 to its communication partner station device 2-2. Having received the RTS frame 12-21 on CH1, the station device 2-2 transmits a CTS frame 12-22. The Duration field of the RTS frame 12-21 specifies T21 as the duration for which the obtained transmission opportunity will be maintained, indicating that the period of T21 will be used as the time for frame exchange (frame transmission / reception) 12-23 between the access point device 1-2 and the station device 2-2. Similarly, the Duration field of the CTS frame 12-22 specifies T22 as the duration for which the obtained transmission opportunity will be maintained, indicating that the time until the end of T22 will be used as the time for frame exchange 12-23 between the access point device 1-2 and the station device 2-2. The frame exchange 12-23 is composed of one or more frame transmissions between the access point device 1-2 and the station device 2-2 in the BSS2 corresponding to the OBSS.

[0122] The access point device 1-1 and station device 2-1 belonging to BSS1 can receive the RTS frame 12-21 and the CTS frame 12-22 in the OBSS and update their NAVs according to the Duration field included in each frame. They detect that at least CH1 is occupied by the OBSS for time T21 after receiving the RTS frame 12-21 or for time T22 after receiving the CTS frame 12-22, and manage the BSS1 so that frame transmission / reception does not occur on CH1 during that period. When a transmission opportunity for the primary channel CH1 is acquired by the OBSS, the access point device 1-1 and station device 2-1 belonging to BSS1 and with NPCA enabled may proceed to a step of determining whether to start NPCA.

[0123] The following describes the operation when the NPCA information element includes an NPCA NAV threshold. The access point device 1-1 or station device 2-1 will not transition to the NPCA primary channel if the NAV value set by the OBSS (such as the aforementioned T21 or T22 values) is below the NPCA NAV threshold or a value based on information indicating the NAV threshold ("less than or equal to (≦)" or "less than (<)"). The access point device 1-1 or station device 2-1 may transition to the NPCA primary channel if the NAV value set by the OBSS (such as the aforementioned T21 or T22 values) is above the NPCA NAV threshold ("exceeds (>)" or "greater than or equal to (≧)"). By setting an NPCA NAV threshold as the NPCA primary channel transition condition and controlling transition to the NPCA primary channel, inefficient channel transitions are suppressed.

[0124] 12 shows an example in which the NAV value set by the OBSS (such as the aforementioned T21 and T22 values) exceeds the NPCA NAV threshold, and the access point device 1-1 and the station device 2-1 transition to the NPCA primary channel. A hardware delay equivalent to the aforementioned channel switch delay occurs for the channel transition, the magnitude of which differs depending on the wireless communication device.

[0125] After the access point device 1-1 and the station device 2-1 transition to the NPCA primary channel, the access point device 1-1 waits for a period of xIFS (referring to any type of IFS, such as PIFS, AIFS, or DFIS), and then starts counting down a backoff counter set with a random backoff time. When the value of the backoff counter reaches 0, the access point device 1-1 becomes able to transmit a frame. The example in FIG. 12 shows a case in which the access point device 1-1 acquires and manages a transmission opportunity. In preparation for frame exchange 12-13, the access point device 1-1 transmits an ICF (Initial Control Frame) 12-11, and the station device 2-1 transmits an ICF response 12-12. Although not shown in FIG. 12, if multiple station devices 2A are participating in NPCA, each station device transmits an ICF response 12-12. Note that the frame exchange 12-13 consists of one or more frame transmissions between the access point device 1-1 and the station device 2A in BSS1.

[0126] The ICF 12-11 may be, for example, a Multi-User RTS (MU-RTS) frame or a Buffer Status Report Poll (BSRP) frame. The MU-RTS frame specifies radio resources (radio resource units specified on the frequency axis, time axis, space axis, etc.) to be allocated to each of multiple station devices 2A, and allocates the radio resources to station devices 2A that respond with an ICF response 12-12, and transmits a downlink radio frame. The downlink frame transmission is included in the frame exchange 12-13. Each station device 2A that receives the BSRP frame requests radio resources by transmitting an ICF response 12-12 to notify the amount of data that is scheduled to be transmitted and that is stored in its transmission buffer. The access point device 1-1 that receives the ICF response 12-12 transmits a trigger frame including information specifying the radio resources to be allocated to each station device in response to the request, and each station device transmits an uplink radio frame using the allocated radio resources. The trigger frame transmission and the uplink radio frame transmission are included in the frame exchange 12-13.

[0127] In the example of Fig. 12, since ICF response 12-12 is transmitted on CH2 to CH4, frame exchange 12-13 is also performed on CH2 to CH4. Frame exchange 12-13 may be performed only on the channels from CH2 to CH4 on which ICF response 12-12 was transmitted. For example, if ICF response 12-12 is transmitted only on CH4, which is the NPCA primary channel, and CH2, frame exchange 12-13 may be performed only on CH4 and CH2, resulting in frame exchange in which some 20 MHz subchannels are punctured.

[0128] After the frame exchange 12-13 is completed, the access point device 1-1 and the station device 2A may transition channels from the NPCA primary channel to the primary channel without receiving instructions from other wireless communication devices before the end of the NAV set by the OBSS (T21 set by the RTS frame 12-21, T22 set by the CTS frame 12-22, etc.).

[0129] Alternatively, after the frame exchange 12-13 is completed, the access point 1-1 may transmit a channel return frame 12-14 to the station device 2A to instruct a channel transition from the NPCA primary channel to the primary channel. The NAV value for the primary channel may be stored in the channel return frame 12-14. If the access point device 1-1 has the ability to keep the NAV of the primary channel up to date in addition to the NAV of the NPCA primary channel while operating on the NPCA primary channel, the station device 2A can grasp the latest NAV information for the primary channel before returning from the NPCA primary channel to the primary channel.

[0130] Basically, the access point device 1-1 and the station device 2A return to the primary channel before the end of the NAV set by the OBSS (such as T21 set by the RTS frame 12-21 or T22 set by the CTS frame 12-22). However, if the return to the primary channel occurs after the NAV (such as T21 or T22), the latest NAV information is not normally known and medium access recovery processing is required, resulting in a delay before the station device 2A can resume acquiring transmission opportunities on the primary channel. However, by notifying the latest NAV on the primary channel in the channel return frame 12-14 transmitted by the access point device 1-1 on the NPCA primary channel, the station device 2A does not need to perform medium access recovery processing when transitioning to the primary channel, and can resume acquiring transmission opportunities on the primary channel relatively quickly.

[0131] An example of a procedure for NPCA (Non-Primary Channel Access) in this embodiment will be described with reference to Fig. 13. While Fig. 12 shows an example in which the NAV is calculated based on the RTS frame 12-21 and the CTS frame 12-22 in the OBSS, Fig. 13 differs in that the NAV is calculated from the frame exchange 13-23 in the OBSS. In other respects, for example, the configurations, mechanisms, and behaviors of the ICF 13-11, ICF response 13-12, frame exchange 13-13, and Channel return frame 13-14 in Fig. 13 are the same as those of the ICF 12-11, ICF response 12-12, frame exchange 12-13, and Channel return frame 12-14 in Fig. 12.

[0132] The access point device 1-1 and station device 2-1 belonging to BSS1 receive frame exchange 13-23 in the BSS and, by referencing the PHY header, MAC header, etc., can learn the time (T31) that the primary channel will be occupied by frame exchange 13-23 and the planned use of 20 MHz sub-channels other than the primary channel. The PHY header configuration differs depending on the standard (IEEE802.11a, IEEE802.11b, IEEE802.11g, IEEE802.11n, IEEE802.11ac, IEEE802.11ax, IEEE802.11be, IEEE802.11bn, etc.), so each will be explained below.

[0133] If frame exchange 13-23 starts with an HE PPDU (IEEE802.11ax PPDU), the BSS color field in the HE-SIG-A field can be used to determine whether it corresponds to an OBSS, the Bandwidth field can be used to determine the planned use of other 20 MHz subchannels including the primary channel, and the TXOP field can be used to determine the planned medium occupancy time (equivalent to T31) and set the NAV.

[0134] If frame exchange 13-23 starts with an EHT PPDU (IEEE802.11be PPDU) or a UHR PPDU (IEEE802.11bn PPDU), the BSS color field in the U-SIG field can be used to determine whether it corresponds to an OBSS, the Bandwidth field can be used to determine the planned use of other 20 MHz subchannels including the primary channel, and the TXOP field can be used to determine the planned medium occupancy time (equivalent to T31) and set the NAV.

[0135] If frame exchange 13-23 starts with a VHT PPDU (IEEE802.11ac PPDU), it can be determined whether or not it corresponds to OBSS from the contents of the Group ID field and Partial AID in the VHT-SIG-A field, and the planned use of other 20MHz subchannels including the primary channel can be known from the BW field. The Length field of the L-SIG can be used as a guide to the medium occupancy time (equivalent to T31) to set the NAV.

[0136] If frame exchange 13-23 begins with an HT PPDU (IEEE802.11n PPDU) or non-HT PPDU, it is not possible to obtain from the PHY header information such as whether it corresponds to OBSS, information about the medium occupancy time, or information about the planned use of other 20 MHz subchannels including the primary channel. By decoding the MAC header and referring to Address1, Address2, Address3, and Address4, it is possible to determine whether it corresponds to OBSS, and to obtain information about the medium occupancy time (equivalent to T31) from the Duration field and set the NAV.

[0137] The following describes the operation when the NPCA information element includes the NPCA bandwidth threshold or information indicating the NPCA bandwidth threshold. When the OBSS frame exchange 13-23 begins with an EHT PPDU, the access point device 1-1 or station device 2-1 demodulates the PHY header of the EHT PPDU and can determine whether the OBSS corresponds to the BSS color field in the U-SIG field and determine the planned use of other 20 MHz subchannels, including the primary channel, from the Bandwidth field. If the bandwidth planned for the OBSS exceeds the NPCA bandwidth threshold ("exceeds (>)" or "greater than or equal to (≧)"), the access point device 1-1 or station device 2-1 does not transition to the NPCA primary channel. If the bandwidth planned for the OBSS is below the NPCA bandwidth threshold ("less than or equal to (≦)" or "less than (<)"), the access point device 1-1 or station device 2-1 may transition to the NPCA primary channel. By setting an NPCA bandwidth threshold as the NPCA primary channel transition condition and controlling the transition to the NPCA primary channel, inefficient channel transitions are suppressed.

[0138] The following describes the operation when the NPCA information element includes the NPCA received power threshold or information indicating the NPCA received power threshold. In Fig. 12, the access point device 1-1 or station device 2-1 receives an RTS frame 12-21 or a CTS frame 12-22 and can calculate the OBSS received power (RSSI) related to the wireless frames transmitted and received via the OBSS. In Fig. 13, the access point device 1-1 or station device 2-1 can calculate the OBSS received power related to the wireless frames transmitted and received via the OBSS from an OBSS frame exchange 13-23. When the access point device 1-1 or station device 2-1 receives a frame transmitted and received via the OBSS and its received power (referred to as the OBSS received power) exceeds the NPCA received power threshold ("exceeds (>)" or "greater than or equal to (≧)"), the access point device 1-1 or station device 2-1 does not transition to the NPCA primary channel. The access point device 1-1 or the station device 2-1 may transition to the NPCA primary channel when the OBSS reception power is below the NPCA reception power threshold ("less than or equal to (≦)" or "less than (<)"). By setting the NPCA reception power threshold as the NPCA primary channel transition condition, transition to the NPCA primary channel is controlled, thereby suppressing inefficient channel transitions.

[0139] When the NPCA execution threshold field of the NPCA information element includes multiple conditions, such as an NPCA NAV threshold, an NPCA bandwidth threshold, an NPCA received power threshold, or information indicating some or all of these, the behavior of the access point device 1-1 and the station device 2-1 can vary. For example, the access point device 1-1 and the station device 2-1 may transition to the NPCA channel only when all conditions are met, or may transition to the NPCA channel when a specific combination of multiple conditions (e.g., a combination of the NPCA NAV threshold and the NPCA bandwidth threshold, a combination of the NPCA NAV threshold and the NPCA received power threshold, etc.) is met, or may transition to the NPCA channel when any one of the conditions is met. The condition to be selected may be determined by the policy of the access point device 1-1, or may be specified in any field included in the NPCA information element or in the MIB.

[0140] Figure 3 shows an architecture diagram of a wireless communication device (including an access point device and a station device). For NPCA, we will explain the primitives used for notifications (including requests, responses, confirmations, indications, etc.) between the MAC layer and the PHY layer via the PHY SAP.

[0141] A first example of a Primitive sequence for realizing NPCA will be described with reference to FIG. 14. The MAC layer configures the PHY layer by notifying (also called issuing) the PHY layer with Primitive PHY-CONFIG.request14-1. PHY-CONFIG.request14-1 sets the parameter PHYCONFIG_VECTOR as an argument. PHYCONFIG_VECTOR is a collection of parameters for configuring the PHY layer, such as parameters OPERATING_CHANNEL, CHANNEL_WIDTH, CENTER_FREQUENCY_SEGMENT_0, and CENTER_FREQUENCY_SEGMENT_1. For example, the parameter OPERATING_CHANNEL is information indicating a value used to specify the primary channel, and the parameter CHANNEL_WIDTH is information indicating a value used to specify the operation bandwidth of the wireless communication system. The MAC layer may include a parameter NPCA_CHANNEL in PHYCONFIG_VECTOR to notify the PHY layer of the NPCA primary channel, and the parameter NPCA_CHANNEL may be set with information indicating a value used to specify the NPCA primary channel.

[0142] The information indicating the value used to specify the primary channel (also referred to as primary channel information or primary channel number) is set in dot11CurrentPrimaryChannel of the MIB in the PHY layer. The information indicating the value used to specify the NPCA primary channel (also referred to as NPCA primary channel information or NPCA primary channel number) may be set in a MIB different from dot11CurrentPrimaryChannel in the PHY layer.

[0143] The MAC layer notifies the PHY layer of the data sequence to be requested for transmission using Primitive PHY-DATA.request 14-2, with DATA and USER_INDEX set as arguments. The argument DATA stores the data sequence that the PHY layer is requested to frame and transmit. The PHY layer notifies the PHY layer that it has received the data sequence using Primitive PHY-DATA.confirm 14-3.

[0144] The MAC layer notifies the PHY layer of a request to transmit a wireless frame by setting TXVECTOR as an argument to Primitive PHY-TXSTART.request 14-4. TXVECTOR is a collection of parameters related to the wireless frame generated by the PHY layer, such as parameters FORMAT and CH_BANDWIDTH. The parameter FORMAT is information indicating the type of PPDU (HT PPDU, VHT PPDU, HE PPDU, EHT PPDU, etc.), and the parameter CH_BANDWIDTH is information indicating the transmission bandwidth. The MAC layer may include the parameter NPCA_CHANNEL or a parameter instructing transmission using the NPCA primary channel in TX_VECTOR to notify the PHY layer whether to transmit the wireless frame on the primary channel or the NPCA primary channel. The parameter NPCA_CHANNEL may be a Boolean parameter, and may be used in a manner such that FALSE indicates transmission on the primary channel and TRUE indicates transmission on the NPCA primary channel, or vice versa. When instructed to transmit on the primary channel, the carrier sense procedure first targets the primary channel. On the other hand, when instructed to transmit on the NPCA primary channel, the carrier sense procedure first transitions from the primary channel to the NPCA primary channel, targets the NPCA primary channel, and at least avoids transmission on the primary channel.

[0145] The parameter NPCA_CHANNEL may be set with information indicating a value used to specify the aforementioned NPCA primary channel (also referred to as NPCA primary channel information or NPCA primary channel number). If the parameter NPCA_CHANNEL stores the NPCA primary channel number, it is assumed that transmission on the NPCA primary channel is instructed, and the carrier sense procedure first involves transitioning from the primary channel to the NPCA primary channel, making the NPCA primary channel the target of carrier sense, and at least avoiding transmission on the primary channel. On the other hand, if the value stored in the parameter NPCA_CHANNEL is a special value such as all zeros (all octets are X'00) or all Fs (all octets are X'FF), it is assumed that transmission on the primary channel is instructed, and the carrier sense procedure first involves making the primary channel the target of carrier sense. Note that the special value is not limited to all zeros or all Fs, and may be any value previously set as a number indicating the primary channel, such as the aforementioned primary channel information or primary channel number.

[0146] The PHY layer notifies the MAC layer of the reception of a WLAN frame using the Primitive PHY-RXSTART.request. RXVECTOR is set as an argument to the Primitive PHY-RXSTART.request. RXVECTOR is a collection of parameters related to the wireless frame received by the PHY layer, such as the parameters FORMAT and CH_BANDWIDTH. The parameter FORMAT indicates the type of PPDU (HT PPDU, VHT PPDU, HE PPDU, EHT PPDU, etc.), and the parameter CH_BANDWIDTH indicates the reception bandwidth. The PHY layer may include the parameter NPCA_CHANNEL in RX_VECTOR to notify the MAC layer whether the wireless frame was received on the primary channel or the NPCA primary channel. The parameter NPCA_CHANNEL may be a Boolean value, and may be used such that FALSE indicates reception on the primary channel and TRUE indicates reception on the NPCA primary channel, or vice versa.

[0147] Thus, in the first example, the basic configuration of the PHY layer is first performed by Primitive PHY-CONFIG.request 14-1, and the timing of NPCA execution (channel transition from the primary channel to the NPCA primary channel) may be indicated by Primitive PHY-TXSTART.request.

[0148] A second example of a Primitive sequence for realizing NPCA will be described with reference to Figure 15. In the first example described in Figure 14, Primitive PHY-CONFIG.request notifies NPCA primary channel information from the MAC layer to the PHY layer, but execution of NPCA is instructed by Primitive PHY-TXSART.request. In the second example described in Figure 15, Primitive PHY-CONFIG.request notifies NPCA primary channel information from the MAC layer to the PHY layer and also instructs execution of NPCA. In other respects, the contents described in Figures 14 and 15 are equivalent.

[0149] The MAC layer configures the PHY layer by notifying (also called issuing) the PHY layer with the Primitive PHY-CONFIG.request. PHY-CONFIG.request takes the parameter PHYCONFIG_VECTOR as an argument. For example, PHYCONFIG_VECTOR may include the parameter NPCA_CHANNEL, which may be information indicating a value used to specify the NPCA primary channel. PHYCONFIG_VECTOR may also include the parameter NPCA_CHANNEL_EN. The parameter NPCA_CHANNEL_EN may be a Boolean parameter, and may be used to specify whether the channel should be set to the primary channel when FALSE or the NPCA primary channel when TRUE, or vice versa.

[0150] For example, by issuing PHY-CONFIG.request15-1 with the parameter NPCA_CHANNEL_EN set to FALSE, the channel may first be set to the primary channel, or if it is already set to the NPCA primary channel, NPCA may be cancelled (a channel transition from the NPCA primary channel to the primary channel).When PHY-CONFIG.request15-2 is issued with the parameter NPCA_CHANNEL_EN set to TRUE, NPCA is executed (a channel transition from the primary channel to the NPCA primary channel).

[0151] The MAC layer notifies the PHY layer of a request to transmit a wireless frame by setting TXVECTOR as an argument to Primitive PHY-TXSTART.request15-5. In the second example for implementing NPCA, the channel transition from the primary channel to the NPCA primary channel is completed before issuing PHY-TXSTART.request.

[0152] The information indicating the value used to specify the primary channel (also referred to as primary channel information or primary channel number) is set in MIB dot11CurrentPrimaryChannel in the PHY layer. Information indicating the value used to specify the NPCA primary channel (also referred to as NPCA primary channel information or NPCA primary channel number) may also share MIB dot11CurrentPrimaryChannel in the PHY layer. In other words, primary channel information may be set in dot11CurrentPrimaryChannel when frames are transmitted and received on the primary channel, and NPCA primary channel information may be set when frames are transmitted and received on the NPCA primary channel after NPCA is executed.

[0153] A third example of a Primitive sequence for realizing NPCA will be described with reference to FIG. 16. In the second example described in FIG. 15, the Primitive PHY-CONFIG.request notifies the NPCA primary channel information from the MAC layer to the PHY layer and also instructs the execution of NPCA. In the third example described in FIG. 16, the Primitive PHY-CONFIG.request notifies the NPCA primary channel information from the MAC layer to the PHY layer, but the Primitive PHY-NPCA.request instructs the execution of NPCA from the MAC layer to the PHY layer. In other respects, the contents described in FIG. 15 and FIG. 16 are equivalent. Note that the Primitive PHY-NPCA.request is a different Primitive from the Primitive PHY-CONFIG.request and PHY-TXSTART.request.

[0154] The MAC layer configures the PHY layer by notifying (also called issuing) the PHY layer with the Primitive PHY-CONFIG.request. The PHY-CONFIG.request takes the parameter PHYCONFIG_VECTOR as an argument. For example, the PHYCONFIG_VECTOR may include the parameter NPCA_CHANNEL, which may be information indicating the value used to specify the NPCA primary channel.

[0155] The MAC layer may issue a Primitive PHY-NPCA.request to the PHY layer to instruct a channel transition from the primary channel to the NPCA primary channel. The parameter NPCA_CHANNEL_EN may be included as an argument. The parameter NPCA_CHANNEL_EN may be a Boolean parameter, and may be used to instruct the channel to be set to the primary channel when FALSE and to instruct the channel to be set to the NPCA primary channel when TRUE, or vice versa.

[0156] For example, the MAC layer may notify (or issue) the PHY layer with Primitive PHY-CONFIG.request16-1 to perform basic configuration of the PHY layer and set the channel to the primary channel. Next, the MAC layer may issue Primitive PHY-NPCA.request with the parameter NPCA_CHANNEL_EN set to TRUE to instruct the channel setting from the primary channel to the NPCA primary channel.

[0157] Information indicating the value used to specify the primary channel (also referred to as primary channel information or primary channel number) is set in dot11CurrentPrimaryChannel of the MIB in the PHY layer. Information indicating the value used to specify the NPCA primary channel (also referred to as NPCA primary channel information or NPCA primary channel number) may be set in a MIB different from dot11CurrentPrimaryChannel in the PHY layer.

[0158] The above describes an exemplary embodiment in which a transmission opportunity is acquired by transitioning from a primary channel to a subchannel other than the primary channel and frames are exchanged, using the Non-Primary Channel Access (NPCA) technology as an example. This embodiment can also be applied to Dynamic Subchannel Operation (DSO) technology and In-Device Coexistence (IDC) technology. Modern wireless communication devices are equipped with multiple wireless communication technologies. For example, smartphones are equipped with wireless communication technologies such as 4G / 5G cellular communication technology, Bluetooth (registered trademark), and UWB (Ultra Wideband) in addition to wireless LAN. When different wireless communication technologies use the same frequency band, wireless interference can occur, resulting in degradation of the wireless communication performance of each. One way to avoid this is to use DSO technology or IDC technology, which controls different wireless communication technologies so that they do not use the same frequency during the same time period. [2. Common to all embodiments]

[0159] The communication device according to 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 communication device according to the present invention can also be effective in, for example, a frequency band called a white band (for example, 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.

[0160] The program running on the wireless communication device according to the present invention is a program that controls a CPU and other components (a program that causes a computer to function) so as to realize the functions of the above-described embodiments of the present invention. Information handled by these devices is temporarily stored in RAM during processing, and then stored in various ROMs or HDDs, from which the CPU reads, modifies, and writes the information as needed. Recording media for storing the programs may include semiconductor media (e.g., ROMs, non-volatile memory cards, 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 realizes the functions of the above-described embodiments, but may also realize the functions of the present invention by processing in cooperation with an operating system or other application programs, etc., based on instructions from the program.

[0161] 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 is also included in the present invention. Furthermore, part or all of the communication device in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit. Each functional block of the 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.

[0162] Furthermore, the integrated circuit method is not limited to LSI, and may be realized by dedicated circuits or general-purpose processors. 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.

[0163] It should be noted that the present invention is not limited to the above-described embodiments. The wireless communication device of the present invention is not limited to application to mobile station devices, 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.

[0164] 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. [Industrial Applicability]

[0165] The present invention is suitable for use in a communication device and a communication method. [Explanation of symbols]

[0166] 1-1, 1-2, 1-3, 1-4 Access point device 2-1, 2-12, 2-13, 2-123, 2-2, 2-21, 2-23, 2-213, 2-3, 2-31, 2-32, 2-34, 2-312, 2-4 Station equipment 3-1, 3-2, 3-3, 3-4 Communication area (coverage) 10000-1 Wireless communication device 10001-1 Upper layer section 10001a-1 MAC layer frame generator 10001b-1 Upper layer control unit 10001c-1 Access function section 10002-1 Autonomous distributed control unit 10002a-1 CCA Department 10002b-1 Backoff section 10002c-1 Transmission decision unit 10003-1 Transmitter 10003a-1 Physical layer frame generator 10003b-1 Radio transmitter 10004-1 Receiver 10004a-1 Radio receiving unit 10004b-1 Signal demodulation unit 10005-1 Antenna part 11-11, 11-12, 11-13, 11-14, 11-21, 11-22, 11-23, 11-24, 11-31, 11-32, 11-33, 11-34, 11-41, 11-42, 11-43, 11-44, 11-53, 11-54, 11-61, 11-62, 11-63, 11-64, 11-71, 11-72, 11-81, 11-82 Frame 12-11, 12-12, 12-14, 12-21, 12-22 Frame 12-13, 12-23 frame replacement 13-11, 13-12, 13-14 Frames 13-13, 13-23, Frame replacement 14-1, 14-2, 14-3, 14-4, 14-5 Primitive 15-1, 15-2, 15-3, 15-4, 15-5, 15-6 Primitive 16-1, 16-2, 16-3, 16-4, 16-5, 16-6, 16-7 Primitive 20000-1 MLD access point device 20000-2, 20000-3, 20000-4 sub-access point devices 30000-1 MLD station equipment 30000-2, 30000-3, 30000-4 Substation Equipment

Claims

1. Station device It comprises an upper layer and a lower layer, The upper layer unit determines that the lower layer unit transitions to an NPCA primary channel based on information (first information) indicating one or more values ​​notified by an NPCA (Non-Primary Channel Access) information element. A station device characterized by:

2. 2. The station device according to claim 1, a receiving unit for receiving a frame transmitted by the access point device, the receiving unit receives a first frame transmitted by the access point device; the first frame includes the NPCA information element; 2. The station device according to claim 1.

3. the receiving unit receives a second frame from a wireless communication device other than a BSS (Basic Service Set) configured by the access point device, For the second frame, if at least one of the first information satisfies a channel transition condition, The upper layer notifies the lower layer of a transition to the NPCA primary channel.

3. The station device according to claim 2.

4. One of the first information is a NAV (Network Allocation Vector) threshold, the channel transition condition is that the NAV set based on the second frame exceeds the NAV threshold.

4. The station device according to claim 3.

5. one of the first pieces of information is a bandwidth threshold; the channel transition condition is that the bandwidth set based on the second frame falls below the bandwidth threshold; 4. The station device according to claim 3.

6. one of the first information is a received power threshold, the channel transition condition is that the received power of the second frame falls below the received power threshold.

4. The station device according to claim 3.

7. An access point device for communicating with one or more station devices, A transmitter unit is provided, the transmitting unit transmits a frame to at least one of the one or more station devices; The frame includes an NPCA information element, The NPCA information element includes information indicating an NPCA primary channel.

1. An access point device comprising:

8. The NPCA information element includes information indicating one or more thresholds for a channel transition condition to the NPCA primary channel.

8. The access point device according to claim 7.

9. The threshold is a NAV threshold.

9. The access point device according to claim 8.

10. the threshold is a bandwidth threshold; 9. The access point device according to claim 8.

11. The threshold is a received power threshold.

9. The access point device according to claim 8.

12. A communication method in a wireless communication system configured with an access point device and one or more station devices, The access point device transmits a frame including an NPCA information element to the station device; The NPCA information element includes information indicating an NPCA primary channel and information indicating one or more thresholds for a channel transition condition to the NPCA primary channel; the station device transitions to the NPCA primary channel when a frame received from a wireless communication device other than the BSS constituted by the access point device satisfies the channel transition condition; A communication method comprising:

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