Station device, access point device, and communication method

Abstract

This access point device, which constitutes a Multi-AP wireless communication system, collects, from a station device connected to the access point device, reception signal quality information or the like necessary for cooperative operation among access point devices, handles the reception signal quality information as inter-access point device coordination information, and shares the reception signal quality information with other access point devices. The access point device uses the inter-access point device coordination information for selecting a cooperative operation mode, to thereby realize a Multi-AP wireless communication system that operates efficiently. A management frame including the reception signal quality information may be exchanged as a wireless frame between the access point devices, or may be exchanged as a wired frame between the access point devices via a DS, thereby enabling flexible exchange of management frames according to the environment.

Description

Station device, access point device, and communication method

[0001] The present application claims priority to Japanese Patent Application No. 2024-025779 filed in Japan on February 22, 2024, and Japanese Patent Application No. 2024-134092 filed in Japan on August 9, 2024, the contents of which are incorporated herein by reference.

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

[0003] Wireless LANs can transmit frames using unlicensed bands, which allow wireless communication without requiring permission (license) from a country or region. For personal use, such as at home, wireless Internet access from within a home has been made possible by incorporating wireless LAN access point functionality into a line termination device for connecting to a wide area network (WAN) line to the Internet, or by connecting a wireless LAN access point device (also referred to as an access point device) to the line termination device. That is, wireless LAN station devices (also referred to as station devices), such as smartphones and personal computers, can access the Internet by connecting to the wireless LAN access point device. When wireless LANs were first introduced to homes, there was often only one wireless LAN access point device within a home. However, recently, multiple wireless LAN access point devices have been introduced to expand the coverage of the wireless LAN usage area within a home. In particular, for personal use, wireless LAN mesh networks, which enable wireless communication between wireless LAN access point devices (backhaul) via wireless LAN, are preferred for simplified network construction. On the other hand, for enterprises, wired connections between wireless LAN access point devices using Ethernet (registered trademark) or the like 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.

[0004] Meanwhile, the United States allows the use of the 6 GHz band (5.925-7.125 GHz) as an unlicensed band, while Europe and Japan allow the use of the lower frequencies of the 6 GHz band (5.925-6.425 GHz), with consideration underway for the upper frequencies (6.425-7.125 GHz). Similar considerations are also underway in other countries around the world. Due to these trends, it is expected that wireless LANs will be able to use the 6 GHz band in addition to the 2.4 GHz and 5 GHz bands. To accommodate the expansion of applicable frequencies, the Wi-Fi Alliance has formulated Wi-Fi 6E (registered trademark), an extension of Wi-Fi 6, which will use the 6 GHz band.

[0005] The 6 GHz band is a frequency band from approximately 5.925 to 7.125 GHz, and a total of approximately 1.2 GHz of bandwidth will be newly available, which means that the bandwidth will increase by 14 channels in 80 MHz width conversion and 7 channels in 160 MHz width conversion. Because abundant frequency resources can be used, the maximum channel bandwidth available for one wireless LAN communication system (equivalent to BSS, described below) will be expanded from 160 MHz in IEEE 802.11ax to 320 MHz, double that in IEEE 802.11be.

[0006] While the 2.4 GHz band offers a relatively wide coverage (range of communication), it is subject to significant interference between communication devices and has a relatively narrow available bandwidth. While the 5 GHz and 6 GHz bands offer wide communication bandwidths, they lack wide coverage. Therefore, to realize various services and applications over a wireless LAN, it is desirable to bundle or switch between frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc., or channels or subchannels included in each frequency band) depending on the use case. However, devices using conventional wireless LAN communication standards were unable to bundle and use different frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.) used for communication. Furthermore, to switch frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.), it was necessary to disconnect from the current frequency band and reconnect to another frequency band.

[0007] Therefore, IEEE 802.11be specifies Multi-Link Operation (MLO), which enables a communication device to use multiple frequency bands and connect multiple links. 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 send and receive frames using multiple links simultaneously, but it can also switch link connections (change frequency bands) for sending and receiving frames without reconnecting. The links constituting the multiple links (Multi-Link) here are also referred to as physical layer links.

[0008] Furthermore, toward the standardization of IEEE 802.11bn, discussions are underway regarding a Multi-AP (Multi Access Point) wireless communication system in which multiple wireless LAN access point devices cooperate to transmit and receive frames to a single wireless LAN station device (see Non-Patent Document 1). In conventional technology, a wireless LAN access point device basically transmits frames while considering only the wireless LAN station devices connected to the wireless communication device itself. However, in a Multi-AP wireless communication system (also referred to as a multi-access point wireless communication system, multi-access point communication system, multi-access point system, cooperative multi-access point system, cooperative operation multi-access point system, etc.), a wireless LAN access point device cooperates with other wireless LAN access point devices ("cooperative operation" can also be called "cooperation"), and can transmit frames while considering the wireless LAN station devices connected to the other wireless LAN access point devices. For example, in a conventional wireless LAN access point device (herein referred to as a BSS-AP), propagation path characteristics are estimated by channel sounding only for wireless LAN station devices (herein referred to as BSS-STAs) connected to the wireless communication device for beam forming or the like. However, in a wireless LAN access point device in a multi-AP wireless communication system, other wireless LAN access point devices (herein referred to as OBSS-APs) are required to estimate propagation path characteristics by channel sounding for the wireless LAN station devices (herein referred to as BSS-STAs). In order to efficiently operate multi-AP cooperative operation (also referred to as multi-AP cooperation, cooperation between access point devices, or cooperative operation between access point devices), the wireless LAN station device (BSS-STA) estimates propagation path characteristics by channel sounding between the wireless LAN access point device to which it is connected and also between wireless LAN access point devices (OBSS-APs) other than the wireless LAN access point device to which it is connected.In addition to Channel Sounding, it is also useful for the wireless LAN station device (BSS-STA) to acquire other received signal qualities (RSSI, SNR, SINR, CQI, etc.) of wireless LAN access point devices (OBSS-APs) other than the connected wireless LAN access point device, in addition to the connected wireless LAN access point device.

[0009] IEEE 802.11-23 / 1832-00-00bn, Oct.2023

[0010] The propagation path characteristics and received signal quality between a wireless LAN access point device and a wireless LAN station device change due to the movement of the wireless LAN station device or the movement of people and objects in the environment. When such changes occur, it is desirable that the method of cooperative operation between the wireless LAN access point device (BSS-AP) to which the wireless LAN station device (BSS-STA) is connected and other wireless LAN access point devices (OBSS-APs) also change. Non-Patent Document 1 explains that in order to efficiently function a multi-AP wireless communication system, it is necessary for the BSS-AP to collect information such as received signal quality not only from the BSS-STA but also from the OBSS-STA. However, depending on the number of wireless LAN station devices connected to the multi-AP wireless communication system, the amount of information such as received signal quality (broadly referred to as radio measurement result information) to be handled becomes large, posing a challenge as to how to share this information in the multi-AP wireless communication system.

[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, an access point device according to one embodiment of the present invention is a first access point device that communicates with one or more station devices, and forms a coordinated multi-access point system together with at least a second access point device, and is equipped with a transmitter, a frame generation unit, and an upper layer unit, and the upper layer unit has a control unit and an access function unit, and the frame generation unit generates a management frame, and the control unit decides whether to transmit the management frame from the transmitter unit or forward it to the access function unit, and if forwarding it to the access function unit, the access function unit issues a Primitive to a Distribution System (DS) to notify it.

[0013] (2) Also, an access point device according to one aspect of the present invention is described in (1) above, wherein the management frame includes radio measurement results collected from each of the one or more station devices, and the radio measurement results are the received signal quality of a frame received by each of the one or more station devices from the second access point device.

[0014] (3) Furthermore, an access point device according to one aspect of the present invention is described in (1) above, wherein the management frame includes statistical information on the subchannel used by the first access point device when transmitting the frame.

[0015] (4) Also, an access point device according to one aspect of the present invention is described in (1) above, wherein the management frame includes information on the maximum bandwidth supported by the station device connected to the first access point device.

[0016] (5) Furthermore, an access point device according to one aspect of the present invention is described in (1) above, wherein the management frame is a collaboration request or a collaboration response for establishing the collaborative multi-access point system.

[0017] (6) Furthermore, an access point device according to one aspect of the present invention is described in (1) above, wherein the access function unit is a Distribution System Access Function (DSAF).

[0018] (7) A communication method according to one aspect of the present invention is a communication method in a coordinated multi-access point system consisting of at least a first access point device and a second access point device, in which the first access point device transmits a generated management frame to the second access point device via an interconnection system.

[0019] (8) A station device according to one aspect of the present invention is a station device that communicates with at least a first access point device that forms a coordinated multi-access point system with at least a second access point device, and is equipped with a transmitter and a frame generator, wherein the frame generator generates a management frame, the management frame including statistical information on frames transmitted and received by the station device, and the transmitter transmits the management frame to the first access point device.

[0020] (9) Furthermore, a station device according to an aspect of the present invention is described in (8) above, wherein the statistical information is statistical information of a subchannel used when transmitting a frame.

[0021] According to the present invention, in a multi-AP wireless communication system, a wireless LAN access point device can transfer and share radio measurement results, such as propagation path characteristics and received signal quality, collected from wireless LAN station devices and OBSS-APs, with other wireless LAN access point devices constituting the multi-AP wireless communication system. Each wireless LAN access point device constituting the multi-AP wireless communication system can use the radio measurement results to determine a multi-AP cooperative operation method and parameters for multi-AP cooperative operation.

[0022] FIG. 1 is a diagram showing an example of a frame configuration according to an embodiment of the present invention. FIG. 1 is a diagram showing an example of a frame configuration according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of communication according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing an example of division of a wireless medium according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of a configuration of a communication system according to an embodiment of the present invention. FIG. 5 is a block diagram showing an example of a configuration of a wireless communication device according to an embodiment of the present invention. FIG. 6 is a block diagram showing an example of a configuration of a wireless communication device according to an embodiment of the present invention. FIG. 7 is a diagram showing an example of an architecture of a wireless communication device according to an embodiment of the present invention. FIG. 8 is a diagram showing an example of a primitive sequence according to an embodiment of the present invention. FIG. 9 is a diagram showing an example of a frame configuration according to an embodiment of the present invention. FIG. 10 is a diagram showing an example of a frame sequence according to an embodiment of the present invention. FIG. 11 is a diagram showing an example of a configuration of a communication system according to an embodiment of the present invention. FIG. 12 is a diagram showing an example of a frame sequence according to an embodiment of the present invention. FIG. 13 is a diagram showing an example of an architecture of a wireless communication device according to an embodiment of the present invention. FIG. 14 is a diagram showing an example of a primitive sequence according to an embodiment of the present invention. FIG. 15 is a diagram showing an example of a primitive sequence according to an embodiment of the present invention.

[0023] The communication system according to this embodiment includes a wireless base station device (access point device) and multiple wireless terminal devices (station devices). A network including the access point device and the station devices is called a basic service set (BSS, management range). A station device according to this embodiment can have the functions of an access point device. Similarly, an access point device according to this embodiment can have the functions of a station device. Therefore, hereinafter, when simply referring to a communication device, the communication device can refer to both a station device and an access point device.

[0024] The access point device and station devices within the BSS communicate based on CSMA / CA (Carrier sense multiple access with collision avoidance). This embodiment focuses on infrastructure mode, in which an access point device communicates with multiple station devices. However, the method of this embodiment can also be implemented in ad hoc mode, in which station devices communicate directly with each other. In ad hoc mode, station devices form a BSS in place of access point devices. A BSS in ad hoc mode is also referred to as an IBSS (Independent Basic Service Set). Hereinafter, station devices forming an IBSS in ad hoc mode can also be considered as access point devices. The method of this embodiment can also be implemented in Wi-Fi Direct (registered trademark), in which station devices communicate directly with each other. In Wi-Fi Direct, station devices form groups in place of access point devices. Hereinafter, a group owner station device forming a group in Wi-Fi Direct can also be considered as an access point device.

[0025] In the IEEE 802.11 system, each wireless communication device can transmit frames of multiple frame types that share a common frame format. The frames are defined in the physical (PHY) layer, medium access control (MAC) layer, and logical link control (LLC) layer.

[0026] 8 shows an architecture diagram of a wireless communication device (including an access point device and a station device). The MAC layer corresponds to a layer above the PHY layer. The PHY layer includes a management entity called a Physical Layer Management Entity (PLME), and PHY layer management functions are initiated via the PLME. Similarly, the MAC layer includes a management entity called a Medium Access Control sublayer Management Entity (MLME), and MAC layer management functions are initiated via the MLME.

[0027] The SME (Station Management Entity) is a layer-independent entity whose role is to collect status specific to layers 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 primitives via the MLME SAP. Similarly, an interface called the PLME SAP exists between the SME and PLME, and the PHY layer and SME interact by exchanging primitives via the PLME SAP. Primitives include SET and GET operations.

[0028] 9, the MLME-Associate primitive will be described as a specific example of an MLME SAP Primitive. This primitive is used when a station device connects (associates) with an access point device. An MLME-Associate.request 9-1 is issued from the SME of the station device to the MLME, and the MLME-Associate.request 9-1 causes the station device to transmit an Associate Request frame from its PHY layer to the wireless medium. When the access point device receives an Associate Request frame 9-2, an MLME-Associate.indication 9-3 is issued from the MLME of the access point device to the SME, and an MLME-Associate.response 9-4 is issued from the SME to the MLME. The MLME-Associate.response 9-4 causes the access point device to transmit an Associate Response frame 9-5 from its PHY layer to the wireless medium. When the station device receives the Associate Response frame 9-5, the MLME of the station device issues an MLME-Associate.confirm 9-6 to the SME, and the series of processes related to the Associate are completed. If the Associate is successful, a state in which communication is possible between the station device and the access point device is established.

[0029] The MLME SAP Primitive includes various primitives, such as the MLME-Associate Primitive, for interaction between the SME and the MAC layer, depending on the purpose. Similarly, the PLME SAP Primitive includes various primitives for interaction between the SME and the PHY layer, depending on the purpose. The SME provides an interface not only between the PHY layer and the MAC layer, but also with layers above the MAC layer. Examples of such upper layers include, but are not limited to, the network layer, transport layer, session layer, presentation layer, and application layer, and any layer above the MAC layer may be used.

[0030] FIG. 15 shows an extended architecture diagram when the wireless communication device is an access point device. Multiple BSSs are connected via a distribution system (DS) to form an extended service set (ESS). The implementation method of the DS is not limited to wired connections, but may also include wireless connections. There may be multiple types of DS, including a type intended to interconnect multiple BSSs to form a LAN, a type intended to interconnect multiple BSSs for cooperation between access point devices, and other types depending on the purpose. Alternatively, other systems or entities with a role equivalent to that of a DS may be provided and used to connect multiple BSSs for cooperation between access point devices. As such, there may be multiple types of systems or entities that connect BSSs. Systems that allow BSSs to interconnect with other BSSs are collectively referred to as interconnection systems (IS) (or may also be referred to as interconnection systems), but the name is not limited to this. In this embodiment, a case where a DS is used as an example will be described, but it is of course possible to realize this using systems other than DS.

[0031] A Distribution System Access Function (DSAF) is located above the MAC layer, and the MAC layer and DSAF may exchange primitives via a MAC SAP, or via another SAP (shown as SAP1 in FIG. 15). Primitives may also be exchanged in a two-stage configuration, such as from the MAC layer via an MLME SAP to an SME, and then from the SME via an SAP (shown as SAP2 in FIG. 15) to the DSAF. The DSAF is defined as an entity that provides a function for accessing a DS, and similarly, an entity that provides a function for accessing an IS is defined as an Interconnection System Access Function (ISAF), although the name is not limited to this.

[0032] The DSAF has a DS SAP as an interface with the DS, and can send and receive frames to the DS via the DS SAP. In other words, a wireless communication device can send and receive frames to other wireless communication devices via the DS. Note that the DS SAF is defined as an SAP for accessing the DS, and similarly, an SAP for accessing the IS is defined as an IS SAP (although the name is not limited to this).

[0033] A PHY layer frame is called a physical protocol data unit (PPDU, PHY layer frame, radio frame, or frame). A PPDU consists of a physical layer header (PHY header) containing header information for signal processing at the physical layer, and a physical service data unit (PSDU, PHY layer frame), which is a data unit processed at the physical layer. A PSDU can be composed of an aggregated MPDU (A-MPDU), which aggregates multiple MAC protocol data units (MPDUs), which serve as retransmission units in the radio section.

[0034] The PHY header includes reference signals such as a short training field (STF) used for signal detection and synchronization, and a long training field (LTF) used to acquire channel information for data demodulation, as well as control signals such as a signal (SIG) containing control information for data demodulation. STF is further classified into Legacy-STF (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) depending on the corresponding standard. LTF and SIG are similarly 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 in the same standard, a Universal SIGNAL (U-SIG) field containing additional control information can be included.

[0035] Furthermore, the PHY header can include information for identifying the BSS that is the sender of the frame (hereinafter also referred to as BSS identification information). The information for identifying the BSS can be, for example, the SSID (Service Set Identifier) ​​of the BSS or the MAC address of the access point device of the BSS. The information for identifying the BSS can also be a value unique to the BSS (for example, a BSS Color) other than the SSID or MAC address.

[0036] The PPDU is modulated according to the corresponding standard, for example, in the case of the IEEE 802.11n standard, it is modulated into an Orthogonal Frequency Division Multiplexing (OFDM) signal.

[0037] An MPDU (also called a MAC frame) consists of a MAC header containing header information for signal processing at the MAC layer, a MAC service data unit (MSDU) or frame body, which is a data unit processed at the MAC layer, and a frame check sequence (FCS) that checks whether the frame is error-free (see Figure 10). Multiple MSDUs can also be aggregated as an aggregated MSDU (A-MSDU).

[0038] MAC layer frame types are broadly classified into three types: management frames (also called management frames or wireless management frames) that manage the connection status between wireless communication devices; control frames (also called control frames or wireless control frames) that manage the communication status between wireless communication devices; and data frames that contain actual transmission data. Each type is further classified into multiple subframe types. Control frames include acknowledgement (Ack) frames, request to send (RTS) frames, and clear to send (CTS) frames. Management frames include beacon frames, probe request frames, probe response frames, authentication frames, association request frames, and association response frames. Data frames include data frames and polling (CF-poll) frames. Each wireless communication device can determine the frame type and subframe type of a received frame by reading the contents of the frame control field in the MAC header.

[0039] An MMPDU (MAC Management Protocol) 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 layer header, an MMPDU (stored in the frame body portion in FIG. 10 ), and an inspection portion, and is called a management frame.

[0040] The Ack may include a Block Ack, which can be used to notify completion of reception of multiple MPDUs.

[0041] A beacon frame includes a field that describes the period at which the beacon is transmitted (beacon interval) and the SSID. An access point device can periodically broadcast a beacon frame within a BSS, and a station device can identify access point devices around the station device by receiving the beacon frame. The act of a station device identifying an access point device based on a beacon frame broadcast by an access point device is called passive scanning. On the other hand, the act of a station device searching 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.

[0042] After recognizing an access point device, a station device performs a connection process with the access point device. The connection process is classified into an authentication procedure and an association procedure. The station device transmits an authentication frame (authentication request) to the access point device with which it wishes to connect. Upon receiving the authentication frame, the access point device transmits an authentication frame (authentication response) to the station device, which includes a status code indicating whether the station device has been authenticated. By reading the status code written in the authentication frame, the station device can determine whether its own wireless communication device has been authorized by the access point device. Note that the access point device and station device can exchange authentication frames multiple times.

[0043] 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 manage multiple station devices by setting different AIDs for each station device to which it has issued connection permission.

[0044] After the connection process is completed, the access point device and the station device perform actual data transmission. The IEEE 802.11 system defines a distributed coordination function (DCF), a point coordination function (PCF), and their extended functions (enhanced distributed channel access (EDCA) and hybrid coordination function (HCF)). The following describes an example in which an access point device transmits a signal to a station device using DCF.

[0045] 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 communication. For example, if an access point device, which is a transmitting station, 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. CS, which is performed based on the power of the signal actually received by each wireless communication device (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). When an access point device or station device detects a signal higher than the CCA level, it begins demodulating at least the PHY layer signal.

[0046] The access point device performs carrier sensing for an interframe space (IFS) corresponding to the type of frame to be transmitted, and determines whether the wireless channel is busy or idle. The period during which the access point device performs carrier sensing varies depending on the frame type and subframe type of the frame to be transmitted. The IEEE 802.11 system defines multiple IFSs with different durations, including a short interframe space (SIFS) used for transmission frames assigned the highest priority, a polling interframe space (PCF IFS: PIFS) used for transmission frames with relatively high priority, and a distributed control interframe space (DCF IFS: DIFS) used for transmission frames with the lowest priority. When the access point device transmits a data frame using DCF, the access point device uses the DIFS.

[0047] After waiting for the DIFS, the access point device further waits for a random backoff time to prevent frame collisions. In the IEEE 802.11 system, the random backoff time is set within the contention window (CW). CSMA / CA assumes that a transmission frame sent by a transmitting station is received by a receiving station without interference from other transmitting stations. Therefore, if two transmitting stations transmit frames at the same time, the frames collide, preventing the receiving station from receiving the frames correctly. Therefore, frame collisions are avoided by each transmitting station waiting for a randomly set time before starting transmission. When the access point device determines through carrier sense that the wireless channel is idle, it starts counting down its backoff counter. Only when the backoff counter reaches 0 can it acquire the right to transmit and transmit a frame to the station device. 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. 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.

[0048] Regarding channel access in an IEEE 802.11 system, the acquisition of the transmission right is performed for each 20 MHz bandwidth, as will be further explained using FIG. 11 . For example, assume that a wireless communication system using a total bandwidth of 80 MHz is constructed using IEEE 802.11ax access point devices, with CH1 to CH4, each with a 20 MHz bandwidth. One of CH1 to CH4 is set as the primary channel, and the acquisition of the transmission right based on counting the backoff time and carrier sense on this primary channel also affects the acquisition of the transmission right on other channels. For example, if 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.

[0049] 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, assuming that the primary channel is set to CH1. When station device 2-1 determines that the wireless channel is idle by performing carrier sensing after a random backoff time on CH1, it transmits an RTS frame 11-11 on CH1 and, at the same timing, transmits equivalent frames as RTS frames 11-12 to 11-14 on CH2 to CH4. Upon receiving the RTS frame, access point device 1-1 checks the wireless channel conditions on CH1 to CH4 and, if it determines that the channels are idle, transmits CTS frames 11-21 to 11-24 indicating this on CH1 to CH4, respectively, which are received by station device 2-1. The station device determines that the wireless channels on CH1 to CH4 are available for use and transmits data frames 11-31 to 11-34. In other words, data frames can be transmitted using the entire 80 MHz channel bandwidth.

[0050] On the other hand, even if station device 2-1 transmits an RTS frame, there are cases where it is not possible to receive a CTS frame on any of CH1 to CH4. For example, this may occur when access point device 1-1 receives RTS frames 11-41 to 11-44 on each of CH1 to CH4, checks the wireless channel conditions, 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.

[0051] 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 capable of transmitting data frames because it received the CTS frame on CH1, which is the primary channel, it understands that only CH1 and CH2 are idle, and transmits data frames 11-81 and 11-82. In other words, only 40 MHz of the 80 MHz bandwidth can be used.

[0052] The receiving station, a station device, receives the frame, reads the PHY header of the frame, and demodulates the received frame. The station device can then determine whether the frame is addressed to its own wireless communication device by reading the MAC header of the demodulated signal. The station device can also determine the destination of the frame based on information stored in the PHY header (e.g., a group identifier (GID) stored in the VHT-SIG-A).

[0053] If a station device determines that the 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. The Ack frame is one of the highest-priority frames that is transmitted after waiting only an SIFS period (no random backoff time is taken). The access point device terminates a series of communications upon receiving the Ack frame from the station device. Note that if the station device fails to receive the frame correctly, it will not transmit an Ack. Therefore, if the access point device does not receive an Ack frame from the receiving station within a certain period (SIFS + Ack frame length) after transmitting a frame, it will consider the communication to have failed and terminate the communication. In this way, the end of one communication (also called a burst) 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.

[0054] When a station device determines that a received frame is not addressed to its own wireless communication device, it sets a network allocation vector (NAV) based on the length of the frame described in the PHY header or the like. The station device does not attempt communication during the period set in the NAV. In other words, the station device performs the same operation as when it determines that the wireless channel is busy by physical CS during the period set in the NAV, so communication control using the NAV is also called virtual carrier sense (virtual CS). In addition to being set based on information described in the PHY header, 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.

[0055] In contrast to DCF, in which each wireless communication device performs carrier sensing and autonomously acquires the transmission right, in PCF, a control station called a Point Coordinator (PC) controls the transmission right of each wireless communication device within the BSS. Generally, an access point device becomes the PC and acquires the transmission right of station devices within the BSS.

[0056] 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 the PC controls the transmission right during the CFP. The access point device, which is the PC, broadcasts a beacon frame containing the CFP duration (CFP Max duration) and other information within the BSS prior to PCF communication. The beacon frame broadcast at the start of PCF transmission uses PIFS and is transmitted without waiting for the CW. The station device that receives the beacon frame sets the CFP duration described in the beacon frame as its NAV. Thereafter, until the NAV elapses or a signal announcing the end of the CFP within the BSS (e.g., a data frame including CF-end) is received, the station device can acquire the transmission right only when it receives a signal signaling acquisition of the transmission right 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.

[0057] A wireless medium can be divided into multiple resource units (RUs). FIG. 4 is a schematic diagram showing an example of how a wireless medium is divided. For example, in resource division example 1, a wireless communication device can divide a frequency resource (subcarrier) of the wireless medium into nine RUs. Similarly, in resource division example 2, a wireless communication device can divide a subcarrier of the wireless medium into five RUs. Of course, the resource division example shown in FIG. 4 is merely an example, and, for example, multiple RUs can each be configured with a different number of subcarriers. Furthermore, the wireless medium divided into RUs can include not only frequency resources but also spatial resources. A wireless communication device (e.g., an access point device) can simultaneously transmit frames to multiple wireless communication devices (e.g., multiple station devices) by placing frames addressed to different station devices in each RU. The access point device can include information indicating the division status of the wireless medium (resource allocation information) in the PHY header of a frame transmitted by the wireless communication device itself as common control information. Furthermore, the access point device can include information indicating the RU in which the frame addressed to each station device is placed (resource unit assignment information) as unique control information in the PHY header of the frame transmitted by its own wireless communication device.

[0058] Furthermore, multiple wireless communication devices (e.g., multiple station devices) can simultaneously transmit frames by placing the frames in the RUs assigned to them and transmitting them. After receiving a frame (Trigger frame: TF) containing trigger information transmitted from an access point device, the multiple station devices can wait a predetermined period of time before transmitting the frame. Each station device can grasp the RU assigned to its own wireless communication device based on the information contained in the TF. Furthermore, each station device can acquire the RU by random access based on the TF.

[0059] 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 one frame using the multiple RUs allocated to one station device, or can allocate multiple frames to different RUs for transmission. At least one of the multiple frames can be a frame containing common control information for multiple station devices transmitting resource allocation information.

[0060] A single 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.

[0061] The access point device can assign multiple AIDs to one station device. The access point device can assign RUs to the multiple AIDs assigned to one station device, respectively. The access point device can transmit different frames to the multiple AIDs assigned to one station device using the assigned RUs, respectively. The different frames can be frames of different frame types.

[0062] 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.

[0063] Hereinafter, access point devices and station devices will be collectively referred to as wireless communication devices or communication devices. Information exchanged when one wireless communication device communicates with another wireless communication device will also be referred to as data. In other words, wireless communication devices include access point devices and station devices.

[0064] A wireless communication device has either a function for transmitting a PPDU or a function for receiving a PPDU, or both. Fig. 1 is a diagram showing an example of the configuration of a PPDU transmitted by a wireless communication device. A PPDU conforming to the IEEE 802.11a / b / g standard is configured to include an L-STF, an L-LTF, an L-SIG, and a Data frame (MAC Frame, MAC Frame, payload, data section, data, information bits, etc.). A PPDU conforming to the IEEE 802.11n standard is configured to include an L-STF, an L-LTF, an L-SIG, an HT-SIG, an HT-STF, an HT-LTF, and a Data frame. A PPDU conforming to the IEEE 802.11ac standard includes some or all of the following: L-STF, L-LTF, L-SIG, VHT-SIG-A, VHT-STF, VHT-LTF, VHT-SIG-B, and a MAC frame. A PPDU conforming to the IEEE 802.11ax standard includes some or all of the following: 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 a Data frame. The PPDU under consideration in IEEE 802.11be is configured to include some or all of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, HET-LTF, and Data frames.

[0065] The L-STF, L-LTF, and L-SIG enclosed by dotted lines in Figure 1 are structures commonly used in the IEEE 802.11 standard (hereinafter, L-STF, L-LTF, and L-SIG are also collectively referred to as the L-header). For example, a wireless communication device that complies with the IEEE 802.11a / b / g standard can properly receive an L-header in a PPDU that complies with the IEEE 802.11n / ac standard. A wireless communication device that complies with the IEEE 802.11a / b / g standard can receive a PPDU that complies with the IEEE 802.11n / ac standard, treating it as a PPDU that complies with the IEEE 802.11a / b / g standard.

[0066] 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 information related to the transmitter address (TA), receiver address (RA), and the Duration / ID field used to set the NAV.

[0067] 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 operation for a predetermined period of time). Information on the transmission rate in the L-SIG (RATE field, L-RATE field, L-RATE, L_DATARATE, L_DATARATE field) and information on the transmission period (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.

[0068] 2 is a diagram showing an example of a method for inserting Duration information into an L-SIG. While FIG. 2 shows a PPDU configuration corresponding to the IEEE 802.11ac standard as an example, the PPDU configuration is not limited to this. A PPDU configuration corresponding to the IEEE 802.11n standard, a PPDU configuration corresponding to the IEEE 802.11ax standard, or a PPDU configuration considered in IEEE 802.11be may also be used. TXTIME includes information regarding the length of the PPDU, aPreambleLength includes information regarding the length of the preamble (L-STF + L-LTF), and aPHYHeaderLength includes information regarding the length of the PHY header (L-SIG). L_LENGTH is a virtual period set to ensure compatibility with the IEEE 802.11 standard, and is related to the Signal Extension, L_RATE. ｏｐｓIt is calculated based on aSymbolLength, which is information about the duration of one symbol (symbol, OFDM symbol, etc.), aPHYServiceLength, which indicates the number of bits included in the Service field, and aPHYConvolutionalTailLength, which indicates the number of tail bits of the convolutional code. The wireless communication device can calculate L_LENGTH and include it in the L-SIG. The wireless communication device can also calculate L-SIG Duration. L-SIG Duration indicates information about the duration obtained by adding together the duration of the PPDU including L_LENGTH and the Ack and SIFS that are expected to be transmitted from the destination wireless communication device in response to the PPDU.

[0069] FIG. 3 is a diagram showing an example of L-SIG Duration in L-SIG TXOP Protection. DATA (frame, payload, data, etc.) is composed of a MAC frame and a part of the PHY header, or both. BA is Block Ack or Ack. PPDU includes L-STF, L-LTF, and L-SIG, and can further include any one or more of DATA, BA, RTS, and CTS. The example shown in FIG. 3 shows L-SIG TXOP Protection using RTS / CTS, but CTS-to-Self may also be used. Here, MAC Duration is the period indicated by the value of the Duration / ID field. In addition, the initiator can transmit a CF_End frame to notify the end of the L-SIG TXOP Protection period.

[0070] 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.

[0071] The wireless communication device can transmit the L-SIG multiple times (L-SIG Repetition). For example, the receiving wireless communication device receives the L-SIG transmitted multiple times using MRC (Maximum Ratio Combining), thereby improving the demodulation accuracy of the L-SIG. Furthermore, when the wireless communication device has correctly received the L-SIG using MRC, it can interpret the PPDU including the L-SIG as a PPDU conforming to the IEEE 802.11ax standard.

[0072] Even during the operation of receiving a PPDU, the wireless communication device can perform an operation of receiving a part of a PPDU other than the PPDU (for example, a preamble, L-STF, L-LTF, PHY header, etc., as defined by IEEE 802.11) (also referred to as a dual reception operation). When the wireless communication device detects a part of a PPDU other than the PPDU during the operation of receiving a PPDU, it can update some or all of the destination address, source address, and information related to the PPDU or DATA period.

[0073] Ack and BA can also be called responses (response frames). Also, probe responses, authentication responses, and connection responses can also be called responses.

[0074] 1. First Embodiment A multi-AP wireless communication system is configured from wireless communication systems provided by a plurality of access point devices. The multi-AP wireless communication system according to this embodiment will be described with reference to FIG.

[0075] The wireless communication system 3-1 includes an access point device 1-1 and station devices 2-1, 2-12, 2-13, and 2-123. Furthermore, the station devices 2-1, 2-12, 2-13, and 2-123 are collectively referred to as station device 2A (terminal device 2A) as station devices connected (associated) with the access point device 1-1. The access point device 1-1 and station device 2A are wirelessly connected and can transmit and receive frames to and from each other. Furthermore, the station device 2-12 is connected to the access point device 1-1, but the access point devices 1-1 and 1-2 can cooperate to transmit and receive frames to and from the station device 2-12. The station device 2-13 is connected to the access point device 1-1, but the access point devices 1-1 and 1-3 can cooperate to transmit and receive frames to and from the station device 2-13. Station device 2-123 is connected to access point device 1-1, but access point devices 1-1, 1-2, and 1-3 can cooperate to transmit and receive frames to and from station device 2-123. Station device 2-1 transmits and receives frames only to access point device 1-1, to which it is connected.

[0076] The wireless communication system 3-2 includes an access point device 1-2 and station devices 2-2, 2-21, 2-23, and 2-213. Furthermore, the station devices 2-2, 2-21, 2-23, and 2-213 are 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. Furthermore, the station device 2-21 is connected to the access point device 1-2, but the access point devices 1-2 and 1-3 can cooperate to transmit and receive frames to and from the station device 2-21. The station device 2-23 is connected to the access point device 1-2, but the access point devices 1-2 and 1-3 can cooperate to transmit and receive frames to and from the station device 2-23. Station device 2-213 is connected to access point device 1-2, but access point devices 1-2, 1-1, and 1-3 can cooperate to transmit and receive frames to and from station device 2-213. Station device 2-2 transmits and receives frames only to access point device 1-2, with which it is connected.

[0077] The wireless communication system 3-3 includes an access point device 1-3 and station devices 2-3, 2-31, 2-32, 2-34, and 2-312. Furthermore, 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 can transmit and receive frames to and from each other. Furthermore, the station device 2-31 is connected to the access point device 1-3, but the access point device 1-3 and the access point device 1-1 can cooperate to transmit and receive frames to and from the station device 2-31. The station device 2-32 is connected to the access point device 1-3, but the access point device 1-3 and the access point device 1-2 can cooperate to transmit and receive frames to and from the station device 2-32. Station device 2-34 is connected to access point device 1-3, but access point device 1-3 and access point device 1-4 can cooperate to transmit and receive frames to and from station device 2-34. Station device 2-312 is connected to access point device 1-3, but access point device 1-3, access point device 1-1, and access point device 1-2 can cooperate to transmit and receive frames to and from station device 2-312. Station device 2-3 transmits and receives frames only to access point device 1-3, to which it is connected.

[0078] The wireless communication system 3-4 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 are capable of transmitting and receiving 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.

[0079] 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. ESS refers to a service set that forms a LAN (Local Area Network). In other words, wireless communication devices that belong to the same ESS can be considered to belong to the same network from a higher layer. Furthermore, multiple BSSs are connected via a DS (Distribution System) to form an ESS.

[0080] For example, one multi-AP wireless communication system (referred to as multi-AP wireless communication system A in this embodiment) may be constructed using four wireless communication systems: wireless communication system 3-1, wireless communication system 3-2, wireless communication system 3-3, and wireless communication system 3-4. As another example, one multi-AP wireless communication system (referred to as multi-AP wireless communication system B in this embodiment) may be constructed using three wireless communication systems: wireless communication system 3-1, wireless communication system 3-2, and wireless communication system 3-3, and another multi-AP wireless communication system (referred to as multi-AP wireless communication system C in this embodiment) may be constructed using wireless communication system 3-3 and wireless communication system 3-4. In this case, wireless communication system 3-3 participates in multi-AP wireless communication system B and multi-AP wireless communication system C. In this way, one wireless communication system may participate in two or more multi-AP wireless communication systems. Note that the number of wireless communication systems and the number of multi-AP wireless communication systems shown in FIG. 5 are merely examples. In reality, there is no limit to the number of wireless communication systems, and there is no limit to the number of multi-AP wireless communication systems composed of those wireless communication systems.

[0081] In conventional technology, one station device connects (associates) with one access point device to transmit and receive frames for wireless communication. In a multi-AP wireless communication system, in addition to the conventional technology, multiple access point devices can cooperate to transmit and receive frames with station devices. Basically, the communication areas (also called coverage, which in this example refer to 3-1, 3-2, 3-3, and 3-4) provided by each wireless communication system are configured to overlap. It is desirable to perform appropriate multi-AP cooperative operation depending on the degree of overlap and the status of the station devices.

[0082] 5, the access point device 1-1 is located within the coverage of the wireless communication system 3-2 of the access point device 1-2 and within the coverage of the wireless communication system 3-3 of the access point device 1-3, but outside the coverage of the wireless communication system 3-4 of the access point device 1-4. Similarly, the access point device 1-2 is located within the coverage of the wireless communication system 3-1 of the access point device 1-1 and within the coverage of the wireless communication system 3-3 of the access point device 1-3, but outside the coverage of the wireless communication system 3-4 of the access point device 1-4. Similarly, the access point device 1-3 is located within the coverage of the wireless communication system 3-1 of the access point device 1-1 and within the coverage of the wireless communication system 3-2 of the access point device 1-2, but outside the coverage of the wireless communication system 3-4 of the access point device 1-4. On the other hand, the access point device 1-4 is located within the coverage of the wireless communication system 3-3 of the access point device 1-3, but is located outside the coverage of the wireless communication system 3-1 of the access point device 1-1, and is located outside the coverage of the wireless communication system 3-2 of the access point device 1-2. Therefore, the access point devices 1-1, 1-2, and 1-3 can transmit and receive wireless frames to and from each other, but the access point 1-4 can transmit and receive wireless frames only to and from the access point device 1-3.

[0083] The access point devices 1-1, 1-2, 1-3, and 1-4 that make up the Multi-AP wireless communication system each constitute a wireless communication system, but at least one access point device serves as a parent access point device (parent AP) (also referred to as a Coordinator access point device (Coordinator AP), Sharing access point device (Sharing AP), etc.) and plays a role in issuing instructions to and controlling other access point devices, that is, child access point devices (child APs) (also referred to as Coordinated access point devices (Coordinated AP), Shared access point devices (Shared AP), etc.). Multiple parent access point devices may be arranged in one Multi-AP wireless communication system to provide redundancy or to share roles. Furthermore, the role equivalent to that of a parent access point device does not necessarily have to be played by an access point device, but may instead be played by a network device (such as a network controller, network switch, or network router) connected via a DS.

[0084] When multi-AP collaborative operation is established, each access point device may be assigned a fixed role of parent access point device or child access point device. Alternatively, when multi-AP collaborative operation is established, temporary parent access point devices and temporary child access point devices may be set and dynamically changed depending on the situation. For example, an access point device that has secured a TXOP becomes a parent access point device, and an access point device that shares the TXOP from the parent access point device becomes a child access point device.

[0085] Each access point device constituting the multi-AP wireless communication system may relay frames to be transmitted to or received from station devices connected to other access point devices. For example, a frame transmitted by access point device 1-1 may be received by station device 2-2 via access point device 1-2. A frame transmitted by station device 2-2 may also be received by access point device 1-1 via access point device 2-1.

[0086] The access point devices constituting the multi-AP wireless communication system may cooperate with each other, and one or more access point devices may transmit and receive frames to and from one station device. For example, the access point device 1-1 may be involved in transmitting and receiving frames to and from a station device 2-21 connected to the access point device 1-2.

[0087] There are multiple methods (also referred to as operation modes) for the cooperative operation between access point devices described above. A representative method is joint operation, in which multiple access point devices transmit and receive frames to one station device, and examples of such methods include joint Tx (joint transmission), joint OFDMA, and joint BF (beam forming). For example, the data portion of a frame addressed to station device 2-21 is shared from access point device 1-2 to access point device 1-1, and the access point devices 1-2 and 1-1 synchronize their timing to transmit the frame to station device 2-21, thereby achieving a gain.

[0088] Another typical method is coordinated operation, in which multiple access point devices cooperate by sharing their communication status with each other, adjusting the use of the wireless medium, and ultimately only one access point device transmits and receives frames to one station device. Examples include coordinated OFDMA, coordinated spatial reuse (SR), coordinated beam forming (BF), coordinated TXOP sharing, and coordinated time division multiple access (TDMA). For example, in coordinated OFDMA, frequency resources are allocated so that the frequency resources used by access point device 1-1 and access point device 1-2 do not overlap. As a result, for station device 2-12 and station device 2-21, which are located in an area where their communication areas (coverages) overlap, access point device 1-1 can use frequency resource A for station device 2-12, and access point device 1-2 can use frequency resource B, which does not overlap with frequency resource A, for station device 2-21, to simultaneously transmit and receive frames.

[0089] The method of cooperative operation between access point devices is not limited to the two methods described here, joint operation and coordinated operation, but there are various other methods.

[0090] An example of a MAC Frame format is shown in Figure 10. Here, MAC Frame refers to the Data Frame (MAC Frame, MAC Frame, Payload, Data Section, Data, Information Bits, etc.) in Figure 1 and the MAC Frame in Figure 2. The MAC Frame includes Frame Control, Duration / ID, Address 1, Address 2, Address 3, Sequence Control, Address 4, QoS Control, HT Control, Frame Body, and FCS.

[0091] 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. ESS refers to a service set that forms a LAN (Local Area Network). In other words, wireless communication devices that belong to the same ESS can be considered to belong to the same network from a higher layer. Furthermore, the BSSs are connected via a DS (Distribution System) to form the ESS. Each of the wireless communication systems 3-1, 3-2, 3-3, and 3-4 can also be equipped with multiple wireless communication devices.

[0092] 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 is configured to include an upper layer unit (upper layer processing step) 10001-1, an autonomous distributed control unit (autonomous distributed control step) 10002-1, a transmitter (transmitting step) 10003-1, a receiver (receiving step) 10004-1, and an antenna unit 10005-1.

[0093] 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 within 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 the MAC frame is transmitted to the DS or to the physical layer (the autonomous distributed control unit 10002-1 and physical layer frame generation unit 10003a-1, which will be described later). The upper layer unit may have an access function unit (access function step) 10001c-1 that provides an access function to the DS (or IS). The access function refers to, for example, the DSAF or ISAF.

[0094] 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 may be control information included in a management frame or a control frame.

[0095] 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 is configured to include a CCA unit (CCA step) 10002a-1, a backoff unit (backoff step) 10002b-1, and a transmission determination unit (transmission determination step) 10002c-1.

[0096] The CCA unit 10002a-1 can use either or both of information about the received signal power received via the radio resource and information about the received signal (including information after decoding) notified from the receiving unit 10004-1 to determine the state of the radio resource (including determining whether it is busy or idle). The CCA unit 10002a-1 can notify the backoff unit 10002b-1 and the transmission determination unit 10002c-1 of the state determination information of the radio resource.

[0097] 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.

[0098] The transmission decision unit 10002c-1 makes a transmission decision using either the wireless resource status decision information or the back-off counter value, or both. For example, when the wireless resource status decision information indicates idle and the back-off counter value is 0, the transmission decision unit 10002c-1 can notify the transmission decision information to the transmitting unit 10003-1. Also, when the wireless resource status decision information indicates idle, the transmission decision unit 10003-1 can notify the transmission decision information.

[0099] The transmitting unit 10003-1 includes a physical layer frame generating unit (physical layer frame generating step) 10003a-1 and a wireless transmitting unit (wireless transmitting step) 10003b-1. The physical layer frame generating unit 10003a-1 has the function of generating a physical layer frame (PPDU) based on transmission decision information notified from the transmission decision unit 10002c-1. The physical layer frame generating unit 10003a-1 performs error correction coding, modulation, precoding filter multiplication, etc. on the transmission frame sent from the upper layer. The physical layer frame generating unit 10003a-1 outputs the generated physical layer frame to the wireless transmitting unit 10003b-1.

[0100] The physical layer frame generator 10003a-1 performs error correction coding on the information bits input from the MAC layer, but the unit for performing error correction coding (coding block length) is not limited to any particular value. For example, the physical layer frame generator 10003a-1 can divide the information bit sequence input from the MAC layer into information bit sequences of a predetermined length, and perform error correction coding on each of them to create multiple coding blocks. Note that when constructing the coding blocks, dummy bits can also be inserted into the information bit sequence input from the MAC layer.

[0101] 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 to be used when the wireless communication device instructed to transmit the frame transmits the frame.

[0102] The wireless transmission unit 10003b-1 converts the physical layer frame generated by the physical layer frame generation unit 10003a-1 into a radio frequency (RF) band signal to generate a radio frequency signal. The processing performed by the wireless transmission unit 10003b-1 includes digital-to-analog conversion, filtering, frequency conversion from the baseband band to the RF band, etc.

[0103] The receiving unit 10004-1 includes a wireless receiving unit (wireless receiving step) 10004a-1 and a signal demodulation unit (signal demodulation step) 10004b-1. The receiving unit 10004-1 generates information about received signal power from the RF band signal received by the antenna unit 10005-1. The receiving unit 10004-1 can notify the CCA unit 10002a-1 of information about received signal power and information about the received signal.

[0104] The wireless receiving unit 10004a-1 has the function of converting an RF band signal received by the antenna unit 10005-1 into a baseband signal and generating a physical layer signal (e.g., a physical layer frame). The processing performed by the wireless receiving unit 10004a-1 includes frequency conversion from the RF band to the baseband, filtering, and analog-to-digital conversion.

[0105] The signal demodulation unit 10004b-1 has the function of demodulating the physical layer signal generated by the wireless receiving unit 10004a-1. The processing performed by the signal demodulation unit 10004b-1 includes channel equalization, demapping, error correction decoding, etc. The signal demodulation unit 10004b-1 can extract, for example, information contained in the physical layer header, information contained in the MAC header, and other information contained in the MAC frame from the physical layer signal. The signal demodulation unit 10004b-1 can output the extracted information to the upper layer unit 10001-1. Note that the signal demodulation unit 10004b-1 can extract any or all of the information contained in the physical layer header, information contained in the MAC header, and other information contained in the MAC frame.

[0106] Antenna unit 10005-1 has a function of transmitting the radio frequency signal generated by wireless transmission unit 10003b-1 into wireless space toward other wireless device 10000-1, and also has a function of receiving the radio frequency signal transmitted from other wireless device 10000-1.

[0107] The wireless communication device 10000-1 can include information indicating the period during which the wireless communication device uses the wireless medium in the PHY header or MAC header of a frame to be transmitted, thereby causing wireless communication devices surrounding the wireless communication device to set a NAV for only that period. For example, the wireless communication device 10000-1 can include information indicating that period in the Duration / ID field or Length field of a frame to be transmitted. The NAV period set in the wireless communication devices surrounding the wireless communication device is referred to as the TXOP period (or simply referred to as TXOP, also referred to as transmission opportunity) acquired by the wireless communication device 10000-1. The wireless communication device 10000-1 that has acquired the TXOP is referred to as the TXOP acquirer (TXOP holder). The frame type of the frame transmitted by the wireless communication device 10000-1 to acquire the TXOP is not limited to any particular type, and may be a control frame (e.g., an RTS frame or a CTS-to-self frame) or a data frame.

[0108] The wireless communication device 10000-1, which is a TXOP holder, can transmit frames to wireless communication devices other than the wireless communication device itself during the TXOP. When 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 TXOP period. 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 TXOP period. 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 TXOP period.

[0109] The wireless communication device 1-1 may reserve a TXOP for all communication bands (e.g., Operation bandwidth) over which frames may be transmitted, or may reserve a TXOP for a specific communication band (e.g., Transmission bandwidth) over which frames are actually transmitted.

[0110] The wireless communication device that instructs the wireless communication device 1-1 to transmit a frame during the acquired TXOP 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 a frame in order to cause wireless communication devices in the vicinity of the wireless communication device itself to transmit a management frame such as a Reassociation frame or a control frame such as an RTS / CTS frame.

[0111] Furthermore, we will also explain TXOP in EDCA, a data transmission method different from DCF. The IEEE 802.11e standard is related to EDCA and specifies TXOP from the perspective of quality of service (QoS) guarantee for various services such as video transmission and VoIP. Services are broadly classified into four access categories: VO (VOice), VI (VIdeo), BE (Best Effort), and BK (Background). Generally, the order of priority is VO, VI, BE, and BK. Each access category has parameters such as the minimum CW value (CWmin), the maximum CW value (CWmax), AIFS (Arbitration IFS), which is a type of IFS, and TXOP limit, which are the upper limit of TXOP. The values ​​are set to differentiate between high and low priorities. For example, by setting the CWmin, CWmax, and AIFS of VO, which has the highest priority for voice transmission, to relatively small values ​​compared to other access categories, data transmission can be prioritized over other access categories. For example, in VI, which transmits a relatively large amount of data for video transmission, setting the TXOP limit to a large value makes it possible to secure a longer TXOP than other access categories. In this way, the values ​​of the four parameters of each access category are adjusted to guarantee QoS according to various services.

[0112] In this embodiment, the signal demodulation unit 10004b-1 of the station device performs decoding processing on the received signal at the physical layer and can 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 pre-assigned to the received signal, and error detection using an error correction code that originally has an error detection function (e.g., a low-density parity check code (LDPC)). The decoding processing at the physical layer can be applied to each coding block.

[0113] The upper layer unit 10001-1 receives the physical layer decoding result from the signal demodulation unit 10004b-1 and restores the MAC layer signal. The MAC layer then performs error detection and determines whether the MAC layer signal transmitted by the station device that transmitted the received frame has been restored correctly.

[0114] The wireless communication device may be a multi-link device (MLD) capable of multi-link communication. An access point device compatible with MLD will be referred to as an MLD access point device, and a station device compatible with MLD will be referred to as an MLD station device. Furthermore, MLD access point devices and MLD station devices will also be collectively referred to as MLD wireless communication devices.

[0115] The MLD access point device 20000-1 and the MLD station device 30000-1 will be described using FIG. 16. The MLD wireless communication device is composed of multiple sub-wireless communication devices corresponding to the frequency bands (or channels, or sub-channels) of each link (also referred to as a physical layer link) that constitutes a multi-link. FIG. 16 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, FIG. 16 shows an example in which the MLD station device 30000-1 is composed of three sub-wireless communication devices, in this case three substation devices (30000-2, 300000-3, and 30000-4), but the number of substation devices may be any number greater than or equal to one. In addition, the sub-wireless communication device (sub-access point device, sub-station device, etc.) may be configured as part of the circuitry within the wireless communication device, and may be called a sub-wireless communication unit (sub-access point unit, sub-station unit).

[0116] 16, 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 from a single wireless communication device (10000-1), and its configuration is the same as that described above with reference to FIGS. 6 and 7.

[0117] 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 greater the number of 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) constituting each MLD wireless communication device may vary depending on the grade, class, and capabilities, and these numbers do not have to be the same.

[0118] The substation device 30000-2 connects (associates) with the sub-access point device 20000-2 and establishes link 1. The substation device 30000-3 connects (associates) with the sub-access point device 20000-3 and establishes link 2. The substation device 30000-4 connects (associates) with the sub-access point device 20000-4 and establishes link 3. In the description of this embodiment, the number of links constituting the multi-link is 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 frequencies 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 sub-channel supported by the wireless communication system, and may vary depending on the laws and regulations of each country.

[0119] The procedure for establishing a Multi-AP wireless communication system according to this embodiment (also referred to as a configuration procedure or a formation procedure) is illustrated using the wireless communication device layout diagram shown in Figure 12 as an example. Figure 12 illustrates the access point device 1-1, station devices 2-1, 2-12, 2-13, and 2-123 connected to the access point device 1-1, access point devices 1-2 and 1-3 that cooperate with the access point device 1-1, and access point device 1-4 that does not cooperate with the access point device 1-1, as shown in Figure 5. Station devices 2-2, 2-3, 2-4, and 2-34 are also added for supplementary explanation.

[0120] In this embodiment, the access point devices 1-1, 1-2, 1-3, and 1-4 are assumed to be access point devices that support cooperative operation between access point devices. However, for example, when targeting station device 2A connected to access point device 1-1, the communication area (coverage) of access point device 1-4 does not overlap with that of access point device 1-1. Therefore, in this embodiment, the access point device 1-4 cannot communicate with station device 2A in cooperation with access point device 1-1. Also, as described above, the access point devices 1-1, 1-2, and 1-3 can transmit and receive wireless frames to and from each other, but the access point device 1-4 can transmit and receive wireless frames only to and from access point device 1-3.

[0121] As mentioned above, examples of the method (operation mode) of cooperative operation between access point devices include joint operation and coordinated operation, but the present invention is not limited to these and other methods may be used.

[0122] FIG. 13 is an example of a frame sequence diagram of the wireless communication system establishment procedure (also referred to as the configuration procedure, formation procedure, negotiation procedure, and association procedure) for the case where the access point device 1-1 takes the lead in establishing a multi-AP wireless communication system (referred to as multi-AP wireless communication system B in this embodiment) consisting of wireless communication systems 3-1, 3-2, and 3-3. The access point device 1-1 transmits frame 13-1 to the access point device 1-2 for a collaboration request (also referred to as the configuration request, formation request, negotiation procedure, and association request). The collaboration request frame may include operation mode information that specifies the operation mode of collaboration between the access point devices (joint operation, coordinated operation, etc.). Note that one collaboration request frame may specify only one operation mode, or multiple operation modes.

[0123] The cooperation request frame includes an identifier (ID, BSSID, MAC address, etc.) of the access point device. It may also include protection information for protecting parts of a frame (such as Information Element, Element, and Field) transmitted and received between access point devices after the Multi-AP wireless communication system is established, as well as the data field portion (also referred to as Framebody). The protection information is information required to encrypt the Framebody and generate MME information for the Framebody, and examples of this information include information related to encryption key generation, such as a random value. Other information that may be included include time information (such as a TSF value) used for synchronization between access point devices, and information related to identifying the location of the access point device (such as GPS location information).

[0124] The access point device 1-2 transmits a frame 13-2 for a collaboration response (also referred to as a configuration response, formation response, negotiation response, or association response). The collaboration response frame 13-2 may include status information indicating whether or not to accept the collaboration request from the access point device 1-1. The collaboration response frame may include the protection information for protecting the contents of frames (also referred to as frame bodies) transmitted and received between access point devices after the Multi-AP wireless communication system is established. The collaboration request frame and collaboration response frame are frames belonging to the type of management frame.

[0125] When a multi-AP wireless communication system including an access point device 1-3 in addition to the access point device 1-2 is constructed, the access point device 1-1 may execute the same processing as that executed with the access point device 1-2 described above. That is, the access point device 1-1 may transmit a collaboration request frame 13-3 to the access point device 1-3. In response to the collaboration request, the access point device 1-3 transmits a collaboration response frame 13-4 to the access point device 1-1.

[0126] In this embodiment, it is assumed that when the access point device 1-1 takes the initiative, the access point device 1-1 transmits a cooperation request frame to the access point devices 1-2 and 1-3. However, when constructing one multi-AP wireless communication system, the system is not limited to one access point device transmitting a cooperation request frame, and multiple access point devices may transmit cooperation request frames.

[0127] When access point device 1-2 and access point device 1-3 accept the request for cooperative operation from access point device 1-1, one multi-AP wireless communication system (referred to as multi-AP wireless communication system B in this embodiment) is constructed from the three wireless communication systems 3-1, 3-2, and 3-3.

[0128] The access point devices 1-1, 1-2, and 1-3 constituting the multi-AP wireless communication system B transmit and receive (exchange) inter-access point device cooperation information generated by each access point device. The inter-access point device cooperation information will be described in detail later. In the case of FIG. 13 , the access point device 1-1 transmits management frames 13-5 and 13-6 to the access point devices 1-2 and 1-3, respectively, including inter-access point device cooperation information 1 generated from information collected by the access point device itself. The access point device 1-1 may broadcast the management frames 13-5 and 13-6 as a single frame to the access point devices 1-2 and 1-3. The management frames 13-5 and 13-6 may be frames transmitted periodically, such as beacon signals. The management frames 13-5 and 13-6 may be unsolicited frames transmitted from the access point device 1-1 without a request from another wireless communication system. The management frames 13-5 and 13-6 may be solicited frames transmitted from the access point device 1-1 in response to requests from other access point devices. By using such a method, cooperation information between access point devices can be continuously updated, thereby enabling the construction of a more flexible and appropriate multi-AP wireless communication system.

[0129] Similarly, the access point device 1-2 transmits management frames 13-7 and 13-8, each including access point device cooperation information 2 created from information collected by its own wireless communication device, to the access point devices 1-1 and 1-3. The access point device 1-1 may broadcast the management frames 13-7 and 13-8 as a single frame to the access point devices 1-1 and 1-3. The management frames 12-3 and 13-8 may be frames transmitted periodically, such as beacon signals. The management frames 13-7 and 13-8 may be unsolicited frames transmitted from the access point device 1-2 without a request from another wireless communication system. The management frames 12-7 and 12-8 may be solicited frames transmitted from the access point device 1-2 in response to a request from another wireless communication system.

[0130] Similarly, the access point device 1-3 transmits management frames 13-9 and 13-10, each including access point device cooperation information 3 created from information collected by its own wireless communication device, to the access point devices 1-1 and 1-2. The access point device 1-3 may broadcast the management frames 13-9 and 13-10 as a single frame to the access point devices 1-1 and 1-2. The management frames 13-9 and 13-10 may be frames that are transmitted periodically, such as beacon signals. The management frames 13-9 and 13-10 may be unsolicited frames transmitted from the access point device 1-3 without a request from another wireless communication system. The management frames 13-9 and 13-10 may be solicited frames transmitted from the access point device 1-3 in response to a request from another wireless communication system.

[0131] An access point device that is not participating in the multi-AP wireless communication system may be prevented from referencing the inter-access point cooperation information of access point devices that are participating in the multi-AP wireless communication system. For example, when the multi-AP wireless communication system is established, the inter-access point cooperation information may be encrypted or MME information may be added based on protection information transmitted and received between the access point devices. Alternatively, a frame body that includes the inter-access point cooperation information may be encrypted or MME information may be added.

[0132] Furthermore, the access point devices may include the inter-access point device cooperation information and / or protection information in a collaboration request frame or a collaboration response frame and transmit the frame. For example, the access point device 1-1 may include the inter-access point device cooperation information and / or protection information in a collaboration request frame 13-1 and transmit the frame to the access point device 1-2. The access point device 1-1 may include the inter-access point device cooperation information and / or protection information in a collaboration request frame 13-3 and transmit the frame to the access point device 1-3.

[0133] For example, the access point device 1-2 may include the inter-access point device cooperation information and / or protection information in a collaboration response frame 13-2 and transmit the same to the access point device 1-1. The access point device 1-3 may include the inter-access point device cooperation information and / or protection information in a collaboration response frame 13-4 and transmit the same to the access point device 1-1.

[0134] Each access point device constituting the multi-AP wireless communication system may use the received inter-access point device cooperation information to determine with which other access point devices the access point device will cooperate and in what manner. Each access point device transmits a data frame in accordance with the determined cooperative operation mode, parameters for cooperative operation, etc. In FIG. 13 , when access point device 1-1, which has initiated the configuration of the multi-AP wireless communication system, secures a TXOP, it transmits a data frame 13-11 to station device 2A in accordance with the determined cooperative operation mode, parameters for cooperative operation, etc. Similarly, when access point device 1-2 secures a TXOP, it may transmit a data frame 13-12 to station device 2B, and when access point device 1-3 secures a TXOP, it may transmit a data frame 13-13 to station device 2C.

[0135] When the access point device 1-1 plays the role of a parent access point device and acquires a TXOP to become a TXOP holder, it may share and transfer the acquired TXOP to the access point device 1-2, which plays the role of a child access point device. The access point device 1-2 may further share and transfer the shared TXOP to another child access point device (e.g., access point device 1-3). The child access point device may return the shared TXOP to the parent access point device. The roles of the parent access point device and the child access point device may be dynamically changed. For example, the access point device 1-2 may become the parent access point device, and the access point devices 1-1 and 1-3 may become child access point devices. Alternatively, the access point device 1-3 may become the parent access point device, and the access point devices 1-1 and 1-2 may become child access point devices.

[0136] Access point devices participating in a multi-AP wireless communication system can also participate in other multi-AP wireless communication systems. Figure 11 shows a frame sequence diagram for a case in which access point device 1-1 takes the initiative in establishing multi-AP wireless communication system B, which consists of wireless communication systems 3-1, 3-2, and 3-3. For example, access point device 1-3 can participate in multi-AP wireless communication system C while maintaining its participation in multi-AP wireless communication system B by receiving a collaboration request frame from access point device 1-4 and transmitting a collaboration response frame indicating acceptance. Alternatively, access point device 1-3 may take the initiative in transmitting a collaboration request frame to access point device 1-4 and receiving a collaboration response frame indicating acceptance from access point device 1-4, thereby participating in multi-AP wireless communication system C. There may or may not be a limit on the number of multi-AP wireless communication systems that one access point device can participate in, and an upper limit may be determined based on the capabilities of the access point device.

[0137] 14 shows an example of a sequence diagram for establishing a multi-AP wireless communication system C by receiving a collaboration request frame 14-1 from the access point device 1-4 and transmitting a collaboration response frame 14-2 indicating acceptance. Management frames 14-3 and 14-7 contain access point device cooperation information for the access point device 1-4 and are shared with the access point device 1-3. Management frames 14-4 and 14-8 contain access point device cooperation information for the access point device 1-3 and are shared with the access point device 1-4. In accordance with the collaboration mode and collaboration parameters determined in response to the management frames 14-3 and 14-4, the access point device 1-3 transmits a data frame 14-5 to the station device 2C, and the access point device 1-4 transmits a data frame 14-6 to the station device 2D. In accordance with the cooperative operation mode and parameters for cooperative operation determined in response to the management frames 14-7 and 14-8, the access point device 1-3 transmits a data frame 14-9 to the station device 2C, and the access point device 1-4 transmits a data frame 14-10 to the station device 2D.

[0138] When performing cooperative operations between access point devices, such as joint operations and coordinated operations, it is useful to report to the access point device received signal quality information (also referred to as received signal statistical information) based on measurements of frame reception status from surrounding access point devices (OBSS-APs) observed by the station device. Furthermore, if the received signal quality information also includes content based on measurements of frame reception status from other station devices (Reported STAs) observed by the reporting station device (Reporting STA), this contributes to better joint operations and coordinated operations.

[0139] The access point device generates inter-access point device cooperation information (which may also be referred to as inter-access point device cooperation information, multi-AP cooperation information, multi-AP cooperation information, inter-layer cooperation information, etc.) based on received signal quality information collected from station devices connected to its own wireless communication device, frame reception statistical information, frame transmission statistical information (described later), traffic requirement information, station device specification information, etc. Alternatively, the inter-access point device cooperation information may be composed of at least one of received signal quality information, frame reception statistical information, frame transmission statistical information, traffic requirement information, and station device specification information. Note that each piece of information, such as received signal quality information, frame reception statistical information, and frame transmission statistical information, may be referred to as radio measurement information or radio measurement result.

[0140] The frame reception statistical information may, for example, be some or all of the information such as the reception amount (number of received bytes), number of received data frames, number of received management frames, BER (Bit Error Rate), FER (Frame Error Rate), BLER (Block Error Rate) of frames received by the access point device from a station device connected to its own wireless communication device, etc. Furthermore, the information is not limited to these examples and may be any statistical information related to frame reception.

[0141] The frame transmission statistical information may be, for example, some or all of the information such as the transmission amount (number of transmitted bytes) of frames transmitted by the access point device to the station device connected to its own wireless communication device, the number of transmitted data frames, the number of transmitted management frames, the frame collision rate, the retransmission rate, the CW length, the medium occupancy rate, the wireless medium busy rate, the wireless medium idle rate, the channel load, etc. The information is not limited to these examples and may be any statistical information related to frame transmission.

[0142] As another example, the frame transmission statistical information may include statistical information related to the usage status of the channels used by the access point device when transmitting frames from its own wireless communication device. Figure 11 illustrates how, in a wireless communication system using a total bandwidth of 80 MHz from subchannels CH1 to CH4, each with a 20 MHz bandwidth, the channel (bandwidth) used for frame transmission is determined depending on whether each subchannel is busy or idle. Specifically, histogram information showing the distribution of the percentages of use of three types of patterns: (1) transmission using only the primary channel, (2) transmission using only the 40 MHz primary channel, and (3) transmission using the entire 80 MHz bandwidth, may be used as statistical information related to channel usage. While Figure 11 illustrates an example in which the wireless communication system has a total bandwidth of 80 MHz, the number of patterns would increase if the wireless communication system had a total bandwidth of 160 MHz or 320 MHz. Furthermore, IEEE 802.11be also specifies preamble puncturing, which allows other subchannels to be used in 20 MHz increments as long as the primary channel is secured. Therefore, the channel usage status of each 20 MHz subchannel that makes up the wireless communication system can be used as statistical information.

[0143] Traffic requirement information (which may also be referred to as traffic specification, traffic classification, QoS characteristics, etc.) is the traffic requirement of an application operating at the application layer, and may use some or all of the information such as average throughput, maximum throughput, minimum throughput, acceptable frame error rate, acceptable delay, and acceptable jitter value, for example.

[0144] The information included in the station device specification information may indicate the IEEE amendment standard supported by the station device connected to the access point device. Here, the IEEE amendment standard refers to IEEE 802.11a, IEEE 802.11b, IEEE 802.11n (equivalent to Wi-Fi 4), IEEE 802.11ac (equivalent to Wi-Fi 5), IEEE 802.11ax (equivalent to Wi-Fi 6), IEEE 802.11be (equivalent to Wi-Fi 7), etc. The station device specification information may also include histogram information indicating the distribution of the number of station devices conforming to each IEEE amendment standard. In addition, the station device specification information may include histogram information showing the distribution of the maximum bandwidth (20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, etc.) that is actually capable of communication and supported by the station device connected to the access point device.

[0145] As an example of received signal quality information, some or all of RSSI (Received Signal Strength Indicator), SNR (Signal to Noise Ratio), SINR (Signal to Interference plus Noise Ratio), CQI (Channel Quality Indication), etc. may be used, but the information is not limited to these and may be any value or index that evaluates received signal quality.

[0146] Examples of frames that are measured by station devices that create received signal quality information include wireless management frames and wireless control frames transmitted by access point devices. Beacon frames, one example of wireless management frames, are frames that contain information about the capabilities of access point devices and are broadcast by access point devices to surrounding wireless communication devices rather than being transmitted only to specific station devices. Therefore, beacon frames are suitable for understanding the standard (normal) transmission characteristics and signal quality of access point devices.

[0147] In addition, a station device that creates received signal quality information may measure frames transmitted and received between a nearby access point device and other specific station devices in order to understand communication conditions other than beacon frames, including unicast frames (individually addressed frames) and multicast frames (group addressed frames).

[0148] Furthermore, when a station device that generates received signal quality information measures frames such as unicast frames or multicast frames to which beamforming is applied and addressed to the other specific station device, the measured RSSI may be greater than the RSSI of a broadcast frame such as a beacon. In this case, the station device that generates received signal quality information may report received signal quality information generated by taking into account the received signal quality of frames unicast (or multicast) to the other specific station device to the access point device to which it is connected.

[0149] In this embodiment, an access point device participating in a multi-AP wireless communication system may transmit and receive access point device cooperation information to and from other access point devices participating in the multi-AP wireless communication system via a data station. The SME of an access point device, or an upper layer of the access point device, or a coordinator access point device in the multi-AP wireless communication system may use the access point device cooperation information to determine with which other access point devices the access point device will cooperate and in what manner.

[0150] [2. Second Embodiment] The configurations of the wireless communication system, MLD access point device, and MLD station device in the second embodiment are the same as those in the first embodiment and may be implemented in combination with the first embodiment. In the first embodiment, the access point devices 1-1, 1-2, and 1-3 in FIG. 11 are capable of transmitting and receiving wireless frames to and from each other. However, depending on the wireless environment conditions and the access point placement conditions, the reliability of wireless frame transmission and reception between the access point devices constituting the Multi-AP wireless communication system may decrease or may even become impossible. In the second embodiment, the access point devices 1-1, 1-2, and 1-3 are connected via a wired backhaul such as Ethernet in a DS, and collaboration request frames, collaboration response frames, other management frames, control frames, and the like may be transmitted and received via the wired backhaul. While this embodiment uses management frames as an example, this is merely an example, and other frame types such as control frames may also be used.

[0151] The procedure for transmitting and receiving frames between an access point device and another access point device via DS will be explained using the Primitive sequence diagram in Fig. 17, taking as examples the collaboration request frame 13-1 and collaboration response frame 13-2 in the frame sequence diagram in Fig. 13. The type of DS is not limited to wired connections and includes wireless connections, but in the explanation of this embodiment, Ethernet, a typical protocol for wired LANs, will be used.

[0152] In the second embodiment, frames exchanged between the access point devices in FIG. 13 may be transmitted and received on a DS. The access point device 1-1 first issues a DS-MANAGEMENT.request 17-1 from the MLME to the DSAF (or an entity capable of relaying between the MLME and the DSAF, such as an SME) via an SAP (MCA SAP, SAP1, SAP2, etc.). The DS-MANAGEMENT.request is a primitive requesting transmission of a management frame toward the DS. The DS-MANAGEMENT.request 17-1 includes at least the contents to be included in the frame body (equivalent to an MMPDU) of the collaboration request frame 13-1, the identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 as the sender, and the identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 as the destination. Furthermore, DS-MANAGEMENT.request17-1 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0153] If the DSAF parses the contents of the DS-MANAGEMENT.request 17-1 and finds that the MMPDU is encrypted, it adds a header indicating that the MMPDU is encrypted and generates a collaboration request frame 13-1. If the MMPDU is not encrypted but the DS-MANAGEMENT.request 17-1 contains encryption information indicating encryption, it encrypts the MMPDU accordingly and generates a collaboration request frame 13-1. The access point device 1-1 transmits the collaboration request frame 13-1 to the access point device 1-2 from the DS SAP toward the DS. In this example, the DS is configured as an Ethernet wired LAN, and in this case the collaboration request frame 13-1 is an Ethernet format frame. However, the DS configuration is not limited to Ethernet and can be other protocols, and the collaboration request frame 13-1 is generated in accordance with the adopted protocol.

[0154] The access point device 1-2 receives a collaboration request frame 13-1 from the DS via a DS SAP. The DSAF parses the content of the collaboration request frame 13-1 and issues a DS-MANAGEMENT.indication 17-2 to the MLME via a SAP (e.g., MCA SAP, SAP1, SAP2). The DS-MANAGEMENT.indication 17-2 may include the content included in the frame body (equivalent to an MMPDU) of the collaboration request frame 13-1, an identifier (e.g., MAC address, MLD MAC address) of the access point device 1-1 that is the sender, and an identifier (e.g., MAC address, MLD MAC address) of the access point device 1-2 that is the destination. Furthermore, DS-MANAGEMENT.indication17-2 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0155] The access point device 1-2 receives the collaboration request frame from the access point device 1-1 and issues a DS-MANAGEMENT.request 17-3 from the MLME to the DSAF (or an entity that can relay between the MLME and the DSAF, such as an SME) via a SAP (MCA SAP, SAP1, SAP2, etc.) in order to send a collaboration response frame back to the access point device 1-1. The DS-MANAGEMENT.request 17-3 includes at least the content to be included in the frame body (equivalent to an MMPDU) of the collaboration response frame 13-2, the identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 that is the sender, and the identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 that is the destination. Furthermore, DS-MANAGEMENT.request17-3 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0156] The DSAF analyzes (parses) the contents included in the DS-MANAGEMENT.request and transmits a collaboration response frame 13-2 to the access point device 1-1 from the DS SAP toward the DS.

[0157] The access point device 1-1 receives a collaboration response frame 13-2 from the DS via a DS SAP. The DSAF parses the contents of the collaboration response frame 13-2 and issues a DS-MANAGEMENT.indication 17-2 to the MLME via a SAP (e.g., MCA SAP, SAP1, SAP2). The DS-MANAGEMENT.indication 17-4 may include the contents included in the frame body (equivalent to an MMPDU) of the collaboration response frame 13-2, an identifier (e.g., MAC address, MLD MAC address) of the access point device 1-2 that is the sender, and an identifier (e.g., MAC address, MLD MAC address) of the access point device 1-1 that is the destination. Furthermore, DS-MANAGEMENT.indication 17-4 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0158] The access point device 1-1 may issue a DS-AP-NOTIFY.request 17-5 from the MLME to the DSAF (or an entity capable of relaying between the MLME and the DSAF, such as an SME) via a SAP (MCA SAP, SAP1, SAP2, etc.). The DS-AP-NOTIFY.request may have a role of updating information (e.g., mapping information, multi-link establishment information, etc., but may be other information) shared between the access point devices (in this example, between the access point devices 1-1 and 1-2). Similarly, the access point device 1-2 may issue a DS-AP-NOTIFY.request 17-6 from the MLME to the DSAF (or an entity capable of relaying between the MLME and the DSAF, such as an SME) via a SAP (MCA SAP, SAP1, SAP2, etc.) to update the information shared between the access point devices.

[0159] The Primitives DS-MANAGEMENT.request and DS-MANAGEMENT.indication are Primitives used to transmit management frames to the DS. In this embodiment, a collaboration request frame and a collaboration response frame have been used as examples of management frames, but the present invention can also be applied to other management frames, control frames, and the like. For example, management frames 13-5, 13-6, 13-7, 13-8, 13-9, and 13-10, which are intended to be transmitted including cooperation information between access point devices, can also be transmitted from an access point device to other access point devices via the DS using the Primitives DS-MANAGEMENT.request and DS-MANAGEMENT.indication. Any management frame can be targeted, and the present invention can also be applied to Beacons, Authentication Requests / Responses, Association Requests / Responses, Probe Requests / Responses, Action frames, and the like. Action frames also include management frames that transmit Measurement Results.

[0160] In this embodiment, an access point device participating in a multi-AP wireless communication system may transmit and receive access point device cooperation information to and from other access point devices participating in the multi-AP wireless communication system via a data station. The SME of an access point device, or an upper layer of the access point device, or a coordinator access point device in the multi-AP wireless communication system may use the access point device cooperation information to determine with which other access point devices the access point device will cooperate and in what manner.

[0161] [3. Third Embodiment] In the third embodiment, a primitive for unit data frames is extended, and management frames, control frames, and frames belonging to other frame types are exchanged between access point devices via a DS. That is, as a primitive exchanged from an MLME to a DSAF (or an entity that can relay between an MLME and a DSAF, such as an SME) via an SAP (MCA SAP, SAP1, SAP2, etc.), a DS-UNIDATA.request is used instead of the DS-MANAGEMENT.request in the second embodiment, a DS-UNIDATA.request is used instead of the DS-MANAGEMENT.request in the second embodiment, and a DS-STA-NOTIFY.request is used instead of the DS-AP-NOTIFY.request in the second embodiment.

[0162] A conventional DS-UNITDATA.request includes at least a MAC service tuple. The MAC service tuple includes at least an MSDU, a source address, a destination address, routing information, priority information, drop eligible information, service class information, a station vector, and MSDU format information. In this embodiment, the Primitive DS-UNITDATA.request, which requests transmission of unit data toward a DS, is extended for transmitting management frames (or control frames, etc.). Similarly, the Primitive DS-UNITDATA.indication and DS-STA-NOTIFY.request are extended for management frames (or control frames, etc.). In the following explanation, a management frame is used as an example, but the subject is not limited to a management frame and may be a frame belonging to another frame type (for example, a control frame, etc.).

[0163] The procedure for transmitting and receiving frames between an access point device and another access point device via DS will be explained using the primitive sequence diagram in Fig. 18, taking as examples the collaboration request frame 13-1 and collaboration response frame 13-2 in the frame sequence diagram in Fig. 13. The type of DS is not limited to wired connections and includes wireless connections, but in the explanation of this embodiment, it is assumed to be a wired LAN protocol typified by Ethernet.

[0164] In the third embodiment, frames exchanged between the access point devices in Fig. 13 may be transmitted and received on a DS. The access point device 1-1 first issues a DS-UNITDATA.request 18-1 from the MLME to the DSAF (or an entity that can relay between the MLME and the DSAF, such as an SME) via a SAP (MCA SAP, SAP1, SAP2, etc.). In this embodiment, the Primitive DS-UNITDATA.request, which requests transmission of unit data toward the DS, is extended for management frame transmission. For this purpose, DS-UNITDATA.request 18-1 includes at least the contents to be included in the frame body (equivalent to MMPDU in the case of a management frame) of the collaboration request frame 12-1, frame type information indicating whether the frame body is an MMPDU (equivalent to the frame body of a management frame), a control frame, a data frame, or other type, an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 that is the sender, and an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 that is the destination. Furthermore, DS-UNITDATA.request 18-1 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0165] The DSAF analyzes (parses) the contents of the DS-UNITDATA.request 18-1, and if it determines from the frame type information that the frame body is an MMPDU, it generates a management frame with the MMPDU as the frame body, stores it in the frame body section (data section) of the unit data frame format, and may add an encapsulation header (which may also be referred to as an encapsulation field, frame type field, etc.) indicating that the data stored in the frame body section (data section) of the unit data frame format is an MMPDU. In other words, it generates a collaboration request frame 13-1 in which the management frame is encapsulated within the unit data frame. Also, if the MMPDU received in the DS-UNITDATA.request 18-1 is encrypted, it adds a header indicating information indicating encryption and generates the collaboration request frame 13-1. If the MMPDU is not encrypted but encryption information is included in the DS-UNITDATA.request 18-1, it encrypts the MMPDU accordingly and generates the collaboration request frame 13-1. The access point device 1-1 transmits a collaboration request frame 13-1 to the access point device 1-2 from the DS SAP toward the DS. In this example, the DS is configured as an Ethernet wired LAN, in which case the collaboration request frame 13-1 is a frame in Ethernet format. However, the DS configuration is not limited to Ethernet and may be other protocols, and the collaboration request frame 13-1 is generated in accordance with the protocol being adopted.

[0166] The access point device 1-2 receives a collaboration request frame 13-1 from the DS via the DS SAP. The DSAF parses the contents of the collaboration request frame 13-1, references the encapsulation header, and determines whether the frame body (data section) of the unit data frame format contains an MMPDU, a control frame, a data frame, or something else. The DSAF issues a DS-UNITDATA.indication 18-2 to the MLME via a SAP (MCA SAP, SAP1, SAP2, etc.). The DS-UNITDATA.indication includes at least the contents included in the frame body (equivalent to MMPDU in the case of a management frame) of the collaboration request frame 12-1, frame type information indicating whether the frame body is an MMPDU (equivalent to the frame body of a management frame), a control frame, a data frame, or other type, an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 that is the sender, and an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 that is the destination. Furthermore, the DS-UNITDATA.indication 18-2 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has been encrypted, information for encryption, etc.).

[0167] Upon receiving the collaboration request frame 13-1 from the access point device 1-1, the access point device 1-2 issues a DS-UNITDATA.request 18-3 from the MLME to the DSAF (or an entity capable of relaying between the MLME and the DSAF, such as an SME) via an SAP (MCA SAP, SAP1, SAP2, etc.) in order to send a collaboration response frame 13-2 back to the access point device 1-1. The DS-UNITDATA.request 18-3 includes at least the contents to be included in the frame body (equivalent to MMPDU in the case of a management frame) of the collaboration response frame 13-2, frame type information indicating whether the frame body is MMPDU (equivalent to the frame body of a management frame), a control frame, a data frame, or other type, an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 as the sender, and an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 as the destination. Furthermore, DS-UNITDATA.request18-3 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0168] The DSAF analyzes (parses) the contents of the DS-UNITDATA.request 18-3, and if it determines from the frame type information that the frame body is an MMPDU, it generates a management frame with the MMPDU as the frame body, stores it in the frame body section (data section) of the unit data frame format, and also adds an encapsulation header indicating that the frame body section (data section) of the unit data frame format is an MMPDU. In other words, it generates a collaboration response frame 13-2 in which the management frame is encapsulated within the unit data frame. Furthermore, if the MMPDU received in the DS-UNITDATA.request 18-3 is encrypted, it adds a header indicating information indicating encryption and generates the collaboration response frame 13-2. If the MMPDU is not encrypted but encryption information is included in the DS-UNITDATA.request 18-3, it encrypts the MMPDU accordingly and generates the collaboration response frame 13-2. The access point device 1-2 transmits a collaboration response frame 13-2 to the access point device 1-1 from the DS SAP toward the DS. In this example, the DS is configured as an Ethernet wired LAN, in which case the collaboration response frame 13-2 is a frame in Ethernet format. However, the DS configuration is not limited to Ethernet and may be other protocols, and the collaboration response frame 13-2 is generated in accordance with the protocol being adopted.

[0169] The access point device 1-1 receives a collaboration response frame 13-2 from the DS via the DS SAP. The DSAF parses the contents of the collaboration request frame 13-2, references the encapsulation header, and determines whether the data stored in the frame body portion (data portion) of the unit data frame format is an MMPDU. The DSAF issues a DS-UNITDATA.indication 18-4 to the MLME via a SAP (MCA SAP, SAP1, SAP2, etc.). The DS-UNITDATA.indication includes at least the contents of the frame body (equivalent to an MMPDU in the case of a management frame) of the collaboration response frame 13-2, frame type information indicating whether the frame body is an MMPDU (equivalent to the frame body of a management frame), a control frame, a data frame, or other type, an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 that is the sender, and an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 that is the destination. Furthermore, DS-UNITDATA.indication 18-4 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0170] The access point device 1-1 may issue a DS-AP-NOTIFY.request 18-5 from the MLME to the DSAF (or an entity capable of relaying between the MLME and the DSAF, such as an SME) via a SAP (MCA SAP, SAP1, SAP2, etc.). The DS-AP-NOTIFY.request may have a role of updating information (e.g., mapping information, multi-link establishment information, etc., but may be other information) shared between the access point devices (in this example, between the access point devices 1-1 and 1-2). Similarly, the access point device 1-2 may issue a DS-AP-NOTIFY.request 18-6 from the MLME to the DSAF (or an entity capable of relaying between the MLME and the DSAF, such as an SME) via a SAP (MCA SAP, SAP1, SAP2, etc.) to update the information shared between the access point devices.

[0171] So far, we have explained the procedure for exchanging management frames between access point devices via DS by extending the Primitive for unit data frames, but control frames may also be exchanged between access point devices via DS in a similar manner.

[0172] [4. Fourth Embodiment] The configurations of the wireless communication system, MLD access point device, and MLD station device in the fourth embodiment are the same as those of the first embodiment, and may be implemented in combination with the first embodiment, or in combination with some or all of the second and third embodiments. In the fourth embodiment, as in the second embodiment, the access point devices 1-1, 1-2, and 1-3 are connected via a wired backhaul such as Ethernet (registered trademark) in DS, and management frames such as collaboration request frames and collaboration response frames, as well as control frames, data frames, and data units defined in wireless LANs (such as MSDU, MPDU, and MMPDU), may be transmitted and received via the wired backhaul. In this embodiment, collaboration request frames and collaboration response frames are used as examples of management frames, but the present invention is not limited to these.

[0173] The procedure for transmitting and receiving frames between an access point device and another access point device via a DS (DS also includes DS media) will be explained using the Primitive sequence diagram in Figure 19, taking as examples the collaboration request frame 13-1 and collaboration response frame 13-2 in the frame sequence diagram in Figure 13. The type of DS is not limited to wired connections, but also includes wireless connections. In the explanation of this embodiment, as an example, it is assumed that the DS is configured with a wired connection and that Ethernet, a typical protocol for wired LANs, is used.

[0174] In the fourth embodiment, an access point device may transmit management frames via the DS when the destination of the management frame is another access point device connected via the DS, and may also receive management frames from other access point devices via the DS. For example, frames exchanged between the access point devices in FIG. 13 may be transmitted and received over the DS. The DSAF (or other entity, such as an MLME) of the access point device 1-1 issues a DS-MANAGEMENT.request 19-1 to the DS via the DS SAP. The DS-MANAGEMENT.request is a primitive requesting transmission of frame 19-7 to the DS medium. The DS-MANAGEMENT.request 19-1 includes at least fields (also referred to as elements) such as frame content information to be stored in the frame body of frame 19-7, an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 as the sender, and an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 as the destination. The frame content information includes a management frame or a portion of a management frame in a wireless LAN, such as, but not limited to, an action frame or an MMPDU. The frame content information may be in the form of a MAC service tuple, and may include some or all of the information contained in the MAC service tuple. Furthermore, the DS-MANAGEMENT.request 19-1 may include fields such as information indicating whether the MMPDU includes a Mesh Control field (which may be information indicating whether it is a management frame in a mesh network), information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (such as information indicating whether it has been encrypted, information for encryption, etc.).

[0175] In this example, the contents of the MMPDU correspond to a management frame for a collaboration request and collaboration response. In other words, frame 19-7 corresponds to collaboration request frame 13-1. Of course, this is merely an example, and the contents may correspond to other management frames. The DS transmits frame 19-7 (collaboration request frame 13-1) over the DS medium based on the information in the fields included in DS-MANAGEMENT.request 19-1. As a variant, if the DS analyzes (parses) the contents of DS-MANAGEMENT.request 19-1 and finds that the MMPDU is encrypted, it adds a header indicating encryption and generates frame 19-7. If the MMPDU is not encrypted but DS-MANAGEMENT.request 19-1 contains encryption information indicating encryption, it encrypts the MMPDU accordingly and generates frame 19-7. The access point device 1-1 transmits frame 19-7 (collaboration request frame 13-1) over the DS medium to the access point device 1-2. In this example, the DS is configured as an Ethernet wired LAN, in which case the frame 19-7 is an Ethernet format frame. However, the DS configuration is not limited to Ethernet and may be other protocols, and the frame 19-7 is generated in accordance with the protocol being adopted.

[0176] The DSAF (or other entity such as an MLME) of the access point device 1-2 is notified of the reception of frame 19-7 (interaction request frame 13-1) from the DS medium by a DS-MANAGEMENT.indication 19-2 received from the DS via a DS SAP. The DS-MANAGEMENT.indication 19-2 may include frame content information included in the frame body of frame 19-7, an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 that is the sender, and an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 that is the destination. Furthermore, the DS-MANAGEMENT.indication 19-2 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether the MMPDU has already been encrypted, information for encryption, etc.).

[0177] The access point device 1-2 receives a collaboration request frame 13-1 (corresponding to frame 19-7) from the access point device 1-1 and sends a collaboration response frame 13-2 (corresponding to frame 19-8) back to the access point device 1-1. To do this, the DSAF (or another entity such as an MLME) of the access point device 1-2 issues a DS-MANAGEMENT.request 19-3 via the DS SAP. The DS-MANAGEMENT.request 19-3 includes at least the frame content information stored in the frame body of the management frame 19-8, the identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 that is the sender, and the identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 that is the destination. Furthermore, DS-MANAGEMENT.request19-3 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0178] The DSAF (or other entity such as an MLME) of the access point device 1-1 is notified of the reception of the collaboration response frame 13-2 by a DS-MANAGEMENT.indication 19-4 received via the DS SAP. The DS-MANAGEMENT.indication 19-4 may include frame content information included in the frame body of frame 19-8 (corresponding to the collaboration response frame 13-2), an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 that is the sender, and an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 that is the destination. Furthermore, the DS-MANAGEMENT.indication 19-4 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether the MMPDU has already been encrypted, information for encryption, etc.).

[0179] The DSAF of the access point device 1-1 (or another entity such as an MLME) may issue a DS-AP-NOTIFY.request 19-5 to the DS via a DS SAP. The DS-AP-NOTIFY.request may include information (e.g., DS mapping information, multi-link establishment information, etc., but may also be other information) shared between the access point devices (between the access point devices 1-1 and 1-2 in this example) and may serve to update this information in the DS. The access point device 1-2 may also similarly issue a DS-AP-NOTIFY.request 19-6 via a DS SAP to update the information shared between the access point devices.

[0180] The Primitives DS-MANAGEMENT.request and DS-MANAGEMENT.indication are basically Primitives used to send and receive management frames via DS. In this embodiment, a collaboration request frame and a collaboration response frame have been used as examples of management frames, but they can also be applied to other management frames. They may also be applied to control frames, data frames, and the like. For example, management frames 13-5, 13-6, 13-7, 13-8, 13-9, and 13-10 in FIG. 13, which are assumed to be transmitted including cooperation information between access point devices, can also be transmitted from an access point device to other access point devices via DS using the Primitives DS-MANAGEMENT.request and DS-MANAGEMENT.indication. When the target is a management frame, they can also be applied to Beacons, Authentication Requests / Responses, Association Requests / Responses, Probe Requests / Responses, Action frames, and the like. Action frames also include management frames that transmit Measurement Results.

[0181] The Ethernet frame format is shown in Figure 21. An Ethernet frame consists of a preamble section, a destination MAC address field, a source MAC address field, an Ether Type field, a payload section, and a CRC (Cyclic Redundancy Check) section. The Ether Type field is used to identify the contents of the payload (frame body) stored in the Ethernet frame. For example, in a typical example, 0x0800 is specified for an IPv4 packet if the payload is an IPv4 packet, and 0x86DD is specified for an IPv6 packet. If a frame defined at the wireless LAN layer is stored in the payload section, 0x890d is specified for the Ether Type. In this embodiment, frames transmitted and received over a DS may be formatted such that the Ether Type is specified as 0x890d in the Ethernet frame and some or all of the information specified in the frame content information is stored in the payload section. A field for identifying the type of management frame may be placed at the beginning of the payload section.

[0182] In this embodiment, an access point device participating in a multi-AP wireless communication system may transmit and receive access point device cooperation information to and from other access point devices participating in the multi-AP wireless communication system via a DS. The SME or MLME of the access point device, or an upper layer of the access point device (which may be the MAC layer, or a layer higher than the MAC layer, such as the application layer), or a coordinator access point device in the multi-AP wireless communication system may use the access point device cooperation information to determine with which other access point devices the access point device will cooperate and in what manner.

[0183] [5. Fifth Embodiment] The configurations of the wireless communication system, MLD access point device, and MLD station device in the fifth embodiment are the same as those of the first embodiment, and may be implemented in combination with the first embodiment, or in combination with some or all of the second, third, and fourth embodiments. In the fifth embodiment, as in the fourth embodiment, the access point devices 1-1, 1-2, and 1-3 are connected via a wired backhaul such as Ethernet in DS, and management frames such as collaboration request frames and collaboration response frames, as well as control frames, data frames, and data units defined in wireless LANs (such as MSDU, MPDU, and MMPDU), may be transmitted and received via the wired backhaul. In this example, a collaboration request frame and a collaboration response frame are used as examples of management frames.

[0184] In the fifth embodiment, the primitive for unit data frames is extended, and management frames, control frames, and frames belonging to other frame types defined in the wireless LAN layer are transmitted and received between access point devices via the DS. In other words, primitives are transmitted and received via the DS SAP between the DSAF (or other entities such as an MLME) and the DS. As a primitive, DS-UNIDATA.request is used instead of the DS-MANAGEMENT.request in the fourth embodiment, and DS-UNIDATA.request is used instead of the DS-MANAGEMENT.request in the fourth embodiment.

[0185] A conventional DS-UNITDATA.request includes at least a MAC service tuple. The MAC service tuple includes at least the following fields: a data (MSDU) field, a source address field, a destination address field, a routing information field, a priority information field, a drop eligible information field, a service class information field, a station vector field, and an MSDU format field. In this embodiment, the Primitive DS-UNITDATA.request, which requests transmission of unit data toward a DS, is extended for transmitting management frames (or control frames, etc.). Similarly, the Primitive DS-UNITDATA.indication is extended for management frames (or control frames, etc.). In the following explanation, a management frame is used as an example, but the subject is not limited to management frames and may be frames belonging to other frame types (e.g., control frames, etc.).

[0186] The procedure for transmitting and receiving frames between an access point device and another access point device via a DS (DS also includes DS media) will be explained using the Primitive sequence diagram in Figure 20, taking as examples the collaboration request frame 13-1 and collaboration response frame 13-2 in the frame sequence diagram in Figure 13. The type of DS is not limited to wired connections, but also includes wireless connections. In the explanation of this embodiment, it is assumed that the DS is configured with a wired connection and that Ethernet, a typical protocol for wired LANs, is used.

[0187] In the fifth embodiment, an access point device transmits management frames via the DS when the destination of the management frame is another access point device connected via the DS, and may also receive management frames from other access point devices via the DS. For example, frames exchanged between the access point devices in FIG. 13 may be transmitted and received over the DS. The DSAF (or other entity such as an MLME) of the access point device 1-1 issues a DS-UNITDATA.request 20-1 to the DS via the DS SAP. In this embodiment, the Primitive DS-UNITDATA.request, which requests the transmission of unit data toward the DS, is extended for management frame transmission. For this purpose, DS-UNITDATA.request 20-1 may include information to be stored in the frame body of frame 20-7 (examples include, but are not limited to, an MMPDU or an action frame), frame type information indicating whether the content to be stored in the frame body corresponds to a management frame (such as an MMPDU), a control frame, a data frame, or other information, an identifier of access point device 1-1 as the sender (MAC address, MLD MAC address, etc.), an identifier of access point device 1-2 as the destination (MAC address, MLD MAC address, etc.), etc. Furthermore, DS-UNITDATA.request 20-1 may include information indicating whether the MMPDU includes a Mesh Control field (which may be information indicating whether it is a management frame in a Mesh network), information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0188] In this example, the contents of the MMPDU correspond to a management frame for a collaboration request and collaboration response. In other words, frame 20-7 corresponds to collaboration request frame 13-1. Of course, this is merely an example, and the contents may correspond to other management frames. If the DS analyzes (parses) the contents of DS-UNITDATA.request 20-1 and determines from the frame type information that it is a management frame (e.g., MMPDU), it may add an encapsulation header (which may also be referred to as an encapsulation field, frame type field, etc.) indicating that what is stored in the data field of the MAC service tuple is a management frame (e.g., MMPDU). In other words, it generates frame 20-7 in which the management frame is encapsulated within a unit data frame. Alternatively, instead of the encapsulation header, one of the fields included in the MAC service tuple may indicate that what is stored in the data field of the MAC service tuple is a management frame (e.g., MMPDU). Furthermore, if the MMPDU received in the DS-UNITDATA.request 20-1 is encrypted, a header indicating that it is encrypted is added to generate frame 20-7. If the MMPDU is not encrypted but encryption information is included in the DS-UNITDATA.request 20-1, the MMPDU is encrypted accordingly to generate frame 20-7. The access point device 1-1 transmits frame 20-7 (corresponding to the collaboration request frame 13-1) to the access point device 1-2 via the DS. In this example, the DS is configured as an Ethernet wired LAN, in which case frame 20-7 is an Ethernet format frame. However, the DS configuration is not limited to Ethernet and may be other protocols, and the collaboration request frame 13-1 is generated in accordance with the adopted protocol.

[0189] The DSAF (or other entity such as an MLME) of the access point device 1-2 is notified of the reception of frame 20-7 (interaction request frame 13-1) from the DS medium by DS-UNITDATA.indication 20-2 received from the DS via the DS SAP. The DSAF parses the contents of frame 20-7, references the encapsulation header, and determines whether the frame body portion of the frame format of the unit data is a management frame (e.g., MMPDU), a control frame, a data frame, or other type of frame. Alternatively, instead of the encapsulation header, the DSAF may reference one of the fields included in the MAC service tuple to determine whether the frame stored in the data field of the MAC service tuple is a management frame (e.g., MMPDU), a control frame, a data frame, or other type of frame. DS-UNITDATA.indication 20-2 may include the contents included in the frame body of frame 20-7 (examples include, but are not limited to, an MMPDU, an action frame, etc.), frame type information indicating whether the contents included in the frame body correspond to a management frame (such as an MMPDU), a control frame, a data frame, or other frame, an identifier (MAC address, MLD MAC address, etc.) of access point device 1-1, which is the source, and an identifier (MAC address, MLD MAC address, etc.) of access point device 1-2, which is the destination. Furthermore, DS-UNITDATA.indication 20-2 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has been encrypted, information for encryption, etc.).

[0190] The access point device 1-2 receives a collaboration request frame 13-1 (frame 20-7) from the access point device 1-1 and returns a collaboration response frame 13-2 (frame 20-8) to the access point device 1-1. To this end, the DSAF (or other entity, such as an MLME) of the access point device 1-2 issues a DS-UNITDATA.request 20-3 via the DS SAP. The DS-UNITDATA.request 20-3 may include information such as the contents to be stored in the frame body of the frame 20-8 (such as, but not limited to, an MMPDU or an action frame), frame type information indicating whether the contents to be stored in the frame body correspond to a management frame (such as an MMPDU), a control frame, a data frame, or other information, an identifier (such as a MAC address or MLD MAC address) of the access point device 1-2 that is the sender, and an identifier (such as a MAC address or MLD MAC address) of the access point device 1-1 that is the destination. Furthermore, DS-UNITDATA.request20-3 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has already been encrypted, information for encryption, etc.).

[0191] The DS analyzes (parses) the contents of the DS-UNITDATA.request 20-3, and if it determines from the frame type information that it is a management frame (such as an MMPDU), it also adds an encapsulation header indicating that the data field of the MAC service tuple is a management frame (such as an MMPDU). In other words, it generates a frame 20-8 in which the management frame is encapsulated within the unit data frame. Alternatively, instead of the encapsulation header, one of the fields included in the MAC service tuple may indicate that the data field of the MAC service tuple is a management frame (such as an MMPDU). Furthermore, if the MMPDU received in the DS-UNITDATA.request 20-3 is encrypted, it adds a header indicating information indicating encryption and generates the frame 20-8. If the MMPDU is not encrypted but encryption information is included in the DS-UNITDATA.request 20-3, it encrypts the MMPDU accordingly and generates the frame 20-8. The access point device 1-2 transmits frame 20-8 (corresponding to the collaboration response frame 13-2) to the access point device 1-1 via the DS. In this example, the DS is configured as an Ethernet wired LAN, in which case the collaboration response frame 13-2 is a frame in Ethernet format. However, the DS configuration is not limited to Ethernet and may be other protocols, and frame 20-8 is generated in accordance with the protocol being adopted.

[0192] The DSAF (or other entity such as an MLME) of the access point device 1-1 is notified of the reception of the collaboration response frame 13-2 by the DS-UNITDATA.indication 20-4 received via the DS SAP. The DSAF parses the contents of the frame 20-8, references the encapsulation header, and determines whether the frame body portion of the frame format of the unit data is an MMPDU. Alternatively, instead of the encapsulation header, the DSAF may reference one of the fields contained in the MAC service tuple to determine whether the frame stored in the data field of the MAC service tuple is a management frame (such as an MMPDU), a control frame, a data frame, or something else. The DS-UNITDATA.indication 20-4 may include the contents included in the frame body of the frame 20-8 (examples include, but are not limited to, an MMPDU, an action frame, etc.), frame type information indicating whether the contents included in the frame body correspond to a management frame (such as an MMPDU), a control frame, a data frame, or other frame, an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-2 that is the sender, and an identifier (MAC address, MLD MAC address, etc.) of the access point device 1-1 that is the destination. Furthermore, the DS-UNITDATA.indication 20-4 may include information indicating whether the MMPDU includes a Mesh Control field, information indicating whether the MMPDU includes an MME, and information related to encryption of the MMPDU (information indicating whether it has been encrypted, information for encryption, etc.).

[0193] The DSAF (or other entity such as an MLME) of the access point device 1-1 may issue a DS-AP-NOTIFY.request 20-5 to the DS via a DS SAP. The DS-AP-NOTIFY.request may have a role of updating information (e.g., DS mapping information, multi-link establishment information, etc., but may be other information) shared between the access point devices (between the access point devices 1-1 and 1-2 in this example). The access point device 1-2 may also issue a DS-AP-NOTIFY.request 20-6 via a DS SAP to update the information shared between the access point devices.

[0194] So far, we have explained the procedure for exchanging management frames defined in the wireless LAN layer between access point devices via DS by extending the Primitives DS-UNITDATA.request and DS-UNITDATA.inidication for unit data frames, but control frames defined in the wireless LAN layer can also be exchanged between access point devices via DS in a similar manner.

[0195] The Ethernet frame format is shown in FIG. 21. An Ethernet frame consists of a preamble section, a destination MAC address field, a source MAC address field, an Ether Type field, a payload section, and a CRC (Cyclic Redundancy Check) section. The Ether Type field is used to identify the contents of the payload (frame body) stored in the Ethernet frame. For example, in a typical example, if the payload is an IPv4 packet, 0x0800 is specified, and if it is an IPv6 packet, 0x86DD is specified. If a frame defined at the wireless LAN layer is stored in the payload section, 0x890d is specified as the Ether Type. In this embodiment, frames transmitted and received on a DS may be in a format in which 0x890d is specified as the Ether Type in the Ethernet frame and the frame body of a management frame (equivalent to an MMPDU) is stored in the payload section. The encapsulation header may be placed at the beginning of the payload section or at a specific location. A field for identifying the type of management frame may be placed at the beginning of the payload section or at a specific location. [6. Common to All Embodiments]

[0196] The communication device according to the present invention can communicate in a frequency band (frequency spectrum) that does not require permission to use from a country or region, which is called an unlicensed band, 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 that is not actually used for purposes such as preventing interference between frequencies even though permission to use it for a specific service is granted by a country or region (for example, a frequency band allocated for television broadcasting but unused in some regions), or in a shared spectrum (shared frequency band) that is expected to be shared by multiple operators.

[0197] The program running on the wireless communication device according to the present invention is a program that controls the CPU and other components (programs that cause a computer to function) to implement 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. The information is then read, modified, and written by the CPU as needed. The recording medium for storing the program may be a semiconductor medium (e.g., a ROM, a non-volatile memory card, etc.), an optical recording medium (e.g., a DVD, an MO, an MD, a CD, a BD, etc.), a magnetic recording medium (e.g., a magnetic tape, a flexible disk, etc.), or the like. Furthermore, not only are the functions of the above-described embodiments implemented by executing the loaded program, but the functions of the present invention may also be implemented by processing in cooperation with an operating system or other application programs, etc., based on instructions from the program.

[0198] 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.

[0199] Furthermore, the method of integration is not limited to LSI, but may be realized by a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology, it may also be possible to use an integrated circuit based on that technology.

[0200] 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.

[0201] 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.

[0202] The present invention is suitable for use in a communication device and a communication method.

[0203] 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 device 3-1, 3-2, 3-3, 3-4 Communication area (coverage) 10000-1 Wireless communication device 10001-1 Upper layer unit 10001-a1 MAC layer frame generation unit 10001-b1 Upper layer control unit 10001-c1 Access function unit 10002-1 Autonomous distributed control unit 10002a-1 CCA unit 10002b-1 Backoff unit 10002c-1 Transmission decision unit 10003-1 Transmission unit 10003a-1 Physical layer frame generation unit 10003b-1 Wireless transmission unit 10004-1 Reception unit 10004a-1 Wireless reception unit 10004b-1 Signal demodulation unit 10005-1 Antenna unit 9-1, 9-2, 9-3, 9-4, 9-5, 9-6 Primitive 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 13-1, 13-2, 13-3, 13-4, 13-5, 13-6, 13-7, 13-8, 13-9, 13-10, 13-11, 13-12, 13-13 Frame 14-1, 14-2, 14-3, 14-4, 14-5, 14-6, 14-7, 14-8, 14-9, 14-10 Frame 20000-1 MLD access point device 20000-2, 20000-3, 20000-4 Sub-access point device 30000-1 MLD station device 30000-2, 30000-3, 30000-4 Sub-station device 17-1, 17-2, 17-3, 17-4, 17-5, 17-6 Primitive 18-1, 18-2, 18-3, 18-4, 18-5, 18-6 Primitive 19-1, 19-2, 19-3, 19-4, 19-5, 19-6 Primitive 19-7, 19-8 Frame 20-1, 20-2,20-3, 20-4, 20-5, 20-6 Primitive 20-7, 20-8 Frame,

Claims

1. A first access point device that communicates with one or more station devices, which forms a coordinated multi-access point system with at least a second access point device, and which comprises a transmitter, a frame generator, and an upper layer unit, wherein the upper layer unit has a control unit and an access function unit, the frame generator unit generates a management frame, the control unit decides whether to transmit the management frame from the transmitter unit or forward it to the access function unit, and if forwarding it to the access function unit, the access function unit issues a primitive to a Distribution System (DS) to notify it.

2. The access point device according to claim 1, characterized in that the management frame includes radio measurement results collected from each of the one or more station devices, and the radio measurement results are the received signal quality of frames received by each of the one or more station devices from the second access point device.

3. The access point device according to claim 1, wherein the management frame includes statistical information on a sub-channel used by the first access point device when transmitting a frame.

4. The access point device according to claim 1, wherein the management frame includes information on the maximum bandwidth supported by the station device connected to the first access point device.

5. The access point device according to claim 1, wherein the management frame is a collaboration request or a collaboration response for establishing the coordinated multi-access point system.

6. The access point device according to claim 1, wherein the access function unit is a Distribution System Access Function (DSAF).

7. A communication method in a coordinated multi-access point system consisting of at least a first access point device and a second access point device, characterized in that the first access point device transmits a generated management frame to the second access point device via an interconnection system.

8. A station device that communicates with a first access point device that forms a coordinated multi-access point system with at least a second access point device, comprising a transmitter and a frame generator, wherein the frame generator generates a management frame, the management frame including statistical information on frames transmitted and received by the station device, and the transmitter transmits the management frame to the first access point device.

9. The station device according to claim 8, wherein the statistical information is statistical information of a subchannel used when transmitting a frame.

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