Station device, access point device, and communication method

Abstract

To perform the multi-AP cooperative operation on the basis of inaccurate information, which is an issue when a wireless LAN station device moves after the measurement is performed.SOLUTION: A wireless LAN station device reports information required for cooperative operation between access point devices in a Multi-AP wireless communication system to a wireless LAN access point device without being solicited by the wireless LAN access point device.SELECTED DRAWING: Figure 13

Description

[Technical field]

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

[0002] The Institute of Electrical and Electronics Engineers Inc. (IEEE) is currently working on the specification of IEEE802.11be, which will achieve even faster speeds than the IEEE802.11 wireless LAN (Local Area Network) standard, and wireless LAN devices that comply with the draft specification are appearing on the market. Currently, standardization activities for IEEE802.11bn are scheduled to begin as the successor to IEEE802.11be. The main theme of the IEEE802.11bn standardization is the realization of Ultra High Reliability (UHR).

[0003] In wireless LAN, frames can be transmitted using unlicensed bands that allow wireless communication without requiring permission (license) from a country or region. For personal use such as at home, wireless LAN access has been made possible from within the home by including a wireless LAN access point function in a line termination device for connecting to a WAN (Wide Area Network) line to the Internet, or by connecting a wireless LAN access point device (also called an access point device) to a line termination device. In other words, a wireless LAN station device (also called a station device) such as a smartphone or personal computer can connect to a wireless LAN access point device to access the Internet. When wireless LAN was first introduced to homes, there was often only one wireless LAN access point device in the home, but nowadays, multiple wireless LAN access point devices are being introduced to expand the coverage of the wireless LAN use area in the home. In particular, for personal use, a wireless LAN mesh network that wirelessly communicates between wireless LAN access point devices (backhaul) is preferred to simplify network construction. On the other hand, for enterprises, wired connections such as Ethernet (registered trademark) are preferred between wireless LAN access point devices to increase the reliability of frame transmission. However, since there is a trade-off between communication performance and the complexity of equipment installation, it is sometimes necessary to consider this balance and decide whether to use a wireless or wired connection between wireless LAN access point devices depending on the use case.

[0004] Meanwhile, in the United States, the 6 GHz band (5.925 to 7.125 GHz) can be used as an unlicensed band, while in Europe and Japan, the use of the lower frequencies of the 6 GHz band (5.925 to 6.425 GHz) is permitted, and consideration is also underway for the upper frequencies (6.425 to 7.125 GHz). Similar considerations are also underway in other countries around the world. As a result, it is expected that wireless LAN will be able to use the 6 GHz band in addition to the 2.4 GHz and 5 GHz bands. In order to accommodate the expansion of target frequencies, the Wi-Fi Alliance has formulated Wi-Fi6E (registered trademark), an extension of Wi-Fi6, which will use the 6 GHz band.

[0005] To be precise, the 6GHz band is the frequency band from 5.925 to 7.125GHz, and a total of approximately 1.2GHz of bandwidth will be newly available, which means an increase of 14 channels in 80MHz-wide channels and 7 channels in 160MHz-wide channels. Because abundant frequency resources can be used, the maximum channel bandwidth available for one wireless LAN communication system (equivalent to BSS, described later) will be expanded from 160MHz in IEEE802.11ax to 320MHz, double the bandwidth in IEEE802.11be.

[0006] The 2.4 GHz band has a relatively wide coverage (range of communication), but the available bandwidth is relatively narrow, and the effect of interference between communication devices is large. The 5 GHz and 6 GHz bands have a wide communication bandwidth, but the coverage is not wide. Therefore, in order to realize various services and applications with wireless LAN, it is desirable to bundle or switch the frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc., or channels included in each frequency band, or subchannels included in the channel) used according to the use case. However, in conventional wireless LAN communication devices, it was not possible to bundle and use different frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.) used for communication. In addition, in order to switch frequency bands (2.4 GHz, 5 GHz, 6 GHz, etc.), it was necessary to once disconnect the current frequency band and reconnect to another frequency band.

[0007] Therefore, in IEEE802.11be, MLO (Multi-Link Operation) is specified, which allows a communication device to use multiple frequency bands and connect multiple links. One example is simultaneous operation of three link connections, namely, 2.4 GHz band connection, 5 GHz band connection, and 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 viewpoint of frequency bands, in the future, millimeter waves (45 GHz band, 60 GHz band, etc.) can also be used as one link constituting Multi-Link. According to MLO, a communication device can maintain multiple link connections with different settings related to wireless resources and communication used. In other words, by using MLO, a communication device can simultaneously maintain link connections of different frequency bands. Not only can frames be transmitted and received using multiple links simultaneously, but also it is possible to switch link connections for transmitting and receiving frames (changing frequency bands) without performing a reconnection operation. The links constituting the multiple links (Multi-Link) here are also called physical layer links.

[0008] Furthermore, in preparation for the standardization of IEEE802.11bn, discussions are underway regarding Multi-AP (Multi Access Point), in which multiple wireless LAN access point devices cooperate to transmit and receive frames to one wireless LAN station device (see Non-Patent Document 1). In conventional technology, a wireless LAN access point device basically transmits frames taking into consideration only the wireless LAN station device connected to itself. However, in a Multi-AP wireless communication system, a wireless LAN access point device cooperates with other wireless LAN access point devices ("cooperative operation" may also be called "cooperation"), and becomes able to transmit frames taking into consideration the wireless LAN station devices connected to the other wireless LAN access point devices. For example, a wireless LAN access point device (herein referred to as BSS-AP) in the conventional technology estimates the propagation path characteristics by Channel Sounding only for a wireless LAN station device (herein referred to as BSS-STA) connected to the wireless LAN access point device itself for Beam Forming or the like, but a wireless LAN access point device in a Multi-AP wireless communication system is required to have other wireless LAN access point devices (herein referred to as OBSS-AP) estimate the propagation path characteristics by Channel Sounding for the wireless LAN station device (herein referred to as BSS-STA). In order to efficiently operate Multi-AP cooperative operation (also referred to as Multi-AP cooperation, cooperation between access point devices, and cooperative operation between access point devices), the wireless LAN station device (BSS-STA) estimates the propagation path characteristics by Channel Sounding between the wireless LAN access point device other than the connection destination, in addition to the connection destination wireless LAN access point device. 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 other than the connected wireless LAN access point device (OBSS-AP) in addition to the connected wireless LAN access point device. [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] IEEE 802.11-23 / 0854-00-0,May.2023 Summary of the Invention [Problem to be solved by the invention]

[0010] The propagation path characteristics and the reception 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 a change occurs, it is desirable to change the method of cooperative operation between the wireless LAN access point device to which the wireless LAN station device is connected and other wireless LAN access point devices. In the proposed technology (Non-Patent Document 1), the wireless LAN access point device is the starting point for issuing a trigger to measure the propagation path characteristics and the reception signal quality. However, since it is difficult for the wireless LAN access point device to detect the movement of the wireless LAN station device, if the wireless LAN station device moves after the measurement is performed, the Multi-AP cooperative operation will be performed based on inaccurate information, which is a problem. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, a communication device and a communication method according to the present invention are as follows.

[0012] (1) That is, a station device according to one embodiment of the present invention is connected to a first access point device and includes a receiving unit that receives frames transmitted by a plurality of access point devices including the first access point device, and a transmitting unit that transmits a radio management frame, wherein the radio management frame includes received signal quality information generated by measuring each frame transmitted by the plurality of access point devices, and when the received signal quality information is requested by the first access point device, the station device transmits the radio management frame as a solicited frame, and when the received signal quality information is not requested by the first access point device, at least one of a first method and a second method is executed, wherein the first method notifies an SME of the received signal quality information from an MLME using a primitive, and the second method transmits the radio management frame as an unsolicited frame.

[0013] (2) Moreover, a station device according to one embodiment of the present invention is described in (1) above, and the execution of the first method and the second method is instructed by a primitive from the SME to the MLME.

[0014] (3) Moreover, a station device according to one aspect of the present invention is described in (1) above, wherein the received signal quality information includes at least one of RSSI, SNR, SINR, and CQI of the multiple access point devices.

[0015] (4) Moreover, a station device according to one aspect of the present invention is described in (1) above, wherein the received signal quality information includes capability information of the plurality of access point devices.

[0016] (5) Furthermore, a station device according to one embodiment of the present invention is described in (1) above, and the content of the received signal quality information contained in the solicited frame is different from the content of the received signal quality information contained in the unsolicited frame.

[0017] (6) Moreover, a station device according to one aspect of the present invention is described in (1) above, wherein the received signal quality information includes higher layer traffic requirement information.

[0018] (7) An access point device according to one embodiment of the present invention is an access point device that communicates with station devices, and is connected to a first station device, and is equipped with a transmitting unit that transmits frames and a receiving unit that receives frames, and receives an unsolicited frame including received signal quality information transmitted by the first station device, and the received signal quality information is generated by measuring each frame transmitted by a plurality of access point devices including the access point device to which the first station device is connected.

[0019] (8) A communication method according to one embodiment of the present invention is a communication method used in a communication system including a station device, a first access point device communicating with the station device, and one or more access point devices other than the first access point device, wherein the station device connects to the first access point device, the station device receives frames transmitted by a plurality of access point devices including the first access point device, the station device transmits a radio management frame, the radio management frame includes received signal quality information generated by measuring each frame transmitted by the plurality of access point devices, when the received signal quality information is requested by the first access point device, the station device transmits the radio management frame as a solicited frame, and when the received signal quality information is not requested by the first access point device, the station device executes at least one of a first method and a second method, wherein the first method notifies an SME of the received signal quality information from an MLME using a primitive, and the second method transmits the radio management frame as an unsolicited frame. Effect of the Invention

[0020] According to the present invention, in a Multi-AP wireless communication system, the wireless LAN station device can report the propagation path characteristics and received signal quality between the wireless LAN station device and a surrounding wireless LAN access point device to the wireless LAN access point device without receiving instructions from the wireless LAN access point device, and the method of Multi-AP cooperative operation on the wireless LAN access point device side can be changed with low latency in accordance with the report. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram illustrating an example of communication according to an embodiment of the present invention. [Figure 4] FIG. 1 is a schematic diagram illustrating an example of division of a wireless medium according to one aspect of the present invention. [Diagram 5] FIG. 1 is a diagram illustrating an example of a configuration of a communication system according to an aspect of the present invention. [Figure 6] 1 is a block diagram showing an example of a configuration of a wireless communication device according to an aspect of the present invention. [Figure 7] 1 is a block diagram showing an example of a configuration of a wireless communication device according to an aspect of the present invention. [Figure 8] 1 is an architecture diagram of a wireless communication device according to one aspect of the present invention. [Figure 9] FIG. 1 is a diagram showing an example of a Primitive sequence according to one embodiment of the present invention. [Figure 10] FIG. 2 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. [Figure 11] FIG. 1 is a diagram illustrating an example of a configuration of a communication system according to an aspect of the present invention. [Figure 12] FIG. 1 is a schematic diagram of communication according to one aspect of the present invention. [Figure 13] FIG. 1 is a diagram showing an example of a Primitive sequence according to one embodiment of the present invention. [Figure 14]FIG. 1 is a diagram showing an example of a Primitive sequence according to one embodiment of the present invention. [Figure 15] FIG. 2 is a diagram illustrating an example of a frame format according to an embodiment of the present invention. [Figure 16] 1 is a block diagram showing an example of a configuration of a wireless communication device according to an aspect of the present invention. [Figure 17] FIG. 2 is a diagram illustrating an example of a frame format according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The communication system in this embodiment includes a wireless base station device (access point device: Access point, base station device) and multiple wireless terminal devices (station devices: Station, terminal devices). A network configured with the base station device and the terminal devices is called a basic service set (BSS: Basic service set, management range). The station device according to this embodiment can have the functions of an access point device. Similarly, the 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.

[0023] The base station device and the terminal device in the BSS communicate based on CSMA / CA (Carrier sense multiple access with collision avoidance). In this embodiment, the base station device communicates with a plurality of terminal devices in the infrastructure mode, but the method of this embodiment can also be implemented in the ad-hoc mode in which the terminal devices communicate directly with each other. In the ad-hoc mode, the terminal devices form a BSS in place of the base station device. The BSS in the ad-hoc mode is also referred to as an IBSS (Independent Basic Service Set). In the following, the terminal devices forming the IBSS in the ad-hoc mode can also be considered as the base station device. The method of this embodiment can also be implemented in WiFi Direct (registered trademark) in which the terminal devices directly communicate with each other. In WiFi Direct, the terminal devices form a Group in place of the base station device. In the following, the terminal devices of the Group Owner that form a Group in WiFi Direct can also be considered as the base station device.

[0024] In the IEEE802.11 system, each device can transmit multiple frame types with a common frame format. The frames are defined in the physical (PHY) layer, medium access control (MAC) layer, and logical link control (LLC) layer.

[0025] Figure 8 shows the architecture of a wireless communication device. The MAC layer is the layer above the PHY layer. The PHY layer includes a management entity called the Physical Layer Management Entity (PLME), and the management functions of the PHY layer are activated via the PLME. Similarly, the MAC layer includes a management entity called the Medium Access Control Management Entity (MLME), and the management functions of the MAC layer are activated via the MLME.

[0026] The SME (Station Management Entity) is a layer-independent entity that collects status specific to layers such as PHY and MAC, and sets parameter values ​​specific to layers such as PHY and MAC. There is an interface called MLME SAP (Service Access point) between the SME and MLME, and the MAC layer and SME interact by exchanging primitives via the MLME SAP. Similarly, there is an interface called PLME SAP 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.

[0027] As a specific example of the MLME SAP Primitive, the MLME-Associate primitive will be described with reference to Fig. 9. This primitive is used when a station device connects (associates) to 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 to the wireless medium from the PHY layer. 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 to the wireless medium from the PHY layer. 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.

[0028] In addition to the MLME-Associate primitive, the MLME SAP Primitive also provides various primitives for interaction between the SME and the MAC layer, depending on the purpose. Similarly, the PLME SAP Primitive also provides 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 the upper layers include the network layer, transport layer, session layer, presentation layer, and application layer, but are not limited to these, and may be any layer located above the MAC layer.

[0029] The frame of the PHY layer is called a physical protocol data unit (PPDU, physical layer frame, radio frame, frame). The PPDU is composed of a physical layer header (PHY header) that contains header information for signal processing in the physical layer, and a physical service data unit (PSDU, PHY service data unit, MAC layer frame), which is a data unit processed in the physical layer. The PSDU can be composed of an aggregated MPDU (A-MPDU), which aggregates multiple MAC protocol data units (MPDUs), which are the units of retransmission in the radio section.

[0030] The PHY header includes reference signals such as a short training field (STF) used for signal detection and synchronization, a long training field (LTF) used to acquire channel information for data demodulation, and control signals such as a signal (SIG) containing control information for data demodulation. STFs are 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, and LTFs and SIGs 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, it can include a Universal SIGNAL (U-SIG) field that contains additional control information in anticipation of technical updates in the same standard.

[0031] Furthermore, the PHY header can include information for identifying the BSS that is the source 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 base station device of the BSS. The information for identifying the BSS can also be a value unique to the BSS (for example, BSS Color, etc.) other than the SSID or MAC address.

[0032] The PPDU is modulated according to a corresponding standard, for example, in the case of the IEEE802.11n standard, it is modulated into an Orthogonal Frequency Division Multiplexing (OFDM) signal.

[0033] MPDU is composed of a MAC layer header (MAC header) that contains header information for signal processing at the MAC layer, a MAC service data unit (MSDU) or frame body that is a data unit processed at the MAC layer, and a frame check sequence (FCS) that checks whether there are any errors in the frame. Multiple MSDUs can also be aggregated as an Aggregated MSDU (A-MSDU).

[0034] The frame types of MAC layer frames are broadly classified into three types: management frames (also called management frames or wireless management frames) that manage the connection status between devices, control frames (also called control frames or wireless control frames) that manage the communication status between 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 device can determine the frame type and subframe type of a received frame by reading the contents of the frame control field included in the MAC header.

[0035] The Ack may include a Block Ack, which is capable of notifying completion of reception of multiple MPDUs.

[0036] The beacon frame includes a field that describes the period (Beacon interval) at which the beacon is transmitted and the SSID. The base station device can periodically broadcast the beacon frame within the BSS, and the terminal device can identify the base station devices around the terminal device by receiving the beacon frame. The terminal device's identification of the base station device based on the beacon frame broadcast by the base station device is called passive scanning. On the other hand, the terminal device's exploration of the base station device by broadcasting a probe request frame within the BSS is called active scanning. The base station device can transmit a probe response frame in response to the probe request frame, and the contents of the probe response frame are equivalent to those of the beacon frame.

[0037] After recognizing a base station device, the terminal device performs a connection process with the base station device. The connection process is classified into an authentication procedure and an association procedure. The terminal device transmits an authentication frame (authentication request) to the base station device to which it wishes to connect. When the base station device receives the authentication frame, it transmits an authentication frame (authentication response) to the terminal device that includes a status code indicating whether the terminal device has been authenticated or not. By reading the status code written in the authentication frame, the terminal device can determine whether or not it has been authorized to be authenticated by the base station device. Note that the base station device and the terminal device can exchange authentication frames multiple times.

[0038] Following the authentication procedure, the terminal device transmits a connection request frame to the base station device to perform a connection procedure. When the base station device receives the connection request frame, it determines whether or not to permit the connection of the terminal device, and transmits a connection response frame to notify the result. The connection response frame contains a status code indicating whether or not the connection process is possible, as well as an association identifier (AID) for identifying the terminal device. The base station device can manage multiple terminal devices by setting different AIDs for each terminal device for which it has issued connection permission.

[0039] After the connection process is completed, the base station device and the terminal device perform actual data transmission. In the IEEE802.11 system, a distributed coordination function (DCF: Distributed Coordination Function), a centralized coordination function (PCF: Point Coordination Function), and their extended functions (enhanced distributed channel access (EDCA) and hybrid coordination function (HCF), etc.) are defined. The following describes an example in which a base station device transmits a signal to a terminal device using DCF.

[0040] In DCF, a base station device and a terminal device perform carrier sense (CS) to check the usage status of a wireless channel around the device before communication. For example, when a base station 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 the transmission of a frame on the wireless channel. Hereinafter, a state in which a signal of CCA level or higher is detected on the wireless channel is called a busy state, and a state in which a signal of CCA level or higher is not detected is called an idle state. In this way, CS performed based on the power of a signal actually received by each device (received power level) is called physical carrier sense (physical CS). The CCA level is also called a carrier sense level (CS level) or a CCA threshold (CCA threshold: CCAT). When a signal of CCA level or higher is detected, the base station device and the terminal device start an operation of demodulating at least a PHY layer signal.

[0041] The base station device performs carrier sensing for an inter frame space (IFS) that corresponds to the type of frame to be transmitted, and judges whether the wireless channel is busy or idle. The period during which the base station device performs carrier sensing varies depending on the frame type and subframe type of the frame that the base station device is about to transmit. In the IEEE802.11 system, multiple IFSs with different periods are defined, including a short inter frame space (SIFS: Short IFS) used for transmission frames assigned the highest priority, a polling inter frame space (PCF IFS: PIFS) used for transmission frames with relatively high priority, and a distributed control inter frame space (DCF IFS: DIFS) used for transmission frames with the lowest priority. When the base station device transmits a data frame using DCF, the base station device uses DIFS.

[0042] After waiting for the DIFS, the base station device further waits for a random backoff time to prevent frame collision. In the IEEE802.11 system, the random backoff time is set within a contention window (CW). In CSMA / CA, it is assumed that a transmission frame transmitted by a certain transmitting station is received by a receiving station without interference from other transmitting stations. Therefore, if transmitting stations transmit frames at the same timing, the frames collide with each other and the receiving station cannot receive the frames correctly. Therefore, frame collision is avoided by having each transmitting station wait for a randomly set time before starting transmission. When the base station device determines that the wireless channel is in an idle state by carrier sense, it starts counting down the backoff counter, and only when the backoff counter reaches 0 can it acquire the transmission right and transmit a frame to the terminal device. If the base station device determines that the wireless channel is in a busy state by carrier sense during the backoff counter countdown, it stops counting down the backoff counter. Then, when the wireless channel becomes idle, the base station device waits for the same period (DIFS) as the previous IFS, and then resumes counting down the remaining backoff counter.

[0043] The terminal device, which is the receiving station, receives the frame, reads the PHY header of the frame, and demodulates the received frame. The terminal device can then read the MAC header of the demodulated signal to determine whether the frame is addressed to the terminal device itself. The terminal device can also determine the destination of the frame based on information written in the PHY header (for example, a group identification number (GID: Group identifier, Group ID) written in VHT-SIG-A).

[0044] When the terminal device judges that the received frame is addressed to itself and demodulates the frame without error, it must transmit an Ack frame indicating that the frame was received correctly to the base station device, which is the transmitting station. The Ack frame is one of the highest priority frames that is transmitted only by waiting for the SIFS period (no random backoff time is taken). The base station device ends a series of communications by receiving the Ack frame transmitted from the terminal device. If the terminal device does not receive the frame correctly, the terminal device does not transmit an Ack. Therefore, if the base station device does not receive an Ack frame from the receiving station for a certain period (SIFS + Ack frame length) after transmitting a frame, it terminates the communication as it has failed. In this way, the end of one communication (also called a burst) in the IEEE802.11 system is always determined by the presence or absence of an Ack frame, except in special cases such as the transmission of a notification signal such as a beacon frame or the use of fragmentation to divide the transmission data.

[0045] When a terminal device determines that a received frame is not addressed to the terminal device, the terminal device sets a network allocation vector (NAV) based on the length of the frame described in the PHY header or the like. The terminal device does not attempt communication during the period set in the NAV. In other words, the terminal device performs the same operation as when it determines that the wireless channel is busy by the physical CS during the period set in the NAV, so communication control by the NAV is also called virtual carrier sense (virtual CS). In addition to being set based on the 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 introduced to solve the hidden terminal problem.

[0046] In contrast to DCF, in which each 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 device within the BSS. In general, a base station device becomes the PC and acquires the transmission right for terminal devices within the BSS.

[0047] The communication period by PCF includes a contention free period (CFP) and a contention period (CP). During the CP, communication is performed based on the DCF described above, and during the CFP, the PC controls the transmission right. The base station device, which is the PC, broadcasts a beacon frame in which the CFP period (CFP Max duration) and the like are described in the BSS prior to PCF communication. Note that the PIFS is used for transmitting the beacon frame broadcast at the start of PCF transmission, and it is transmitted without waiting for the CW. The terminal device that receives the beacon frame sets the CFP period described in the beacon frame to the NAV. After that, until the NAV elapses or a signal (e.g., a data frame including CF-end) that broadcasts the end of CFP in the BSS is received, the terminal device can acquire the transmission right only when it receives a signal (e.g., a data frame including CF-poll) that signals the acquisition of the transmission right transmitted from the PC. During the CFP period, no packet collisions occur within the same BSS, so each terminal device does not take the random backoff time used in DCF.

[0048] A wireless medium can be divided into a number of resource units (RUs). FIG. 4 is a schematic diagram showing an example of a division state of a wireless medium. For example, in resource division example 1, a wireless communication device can divide a frequency resource (subcarrier) which is a wireless medium into nine RUs. Similarly, in resource division example 2, a wireless communication device can divide a subcarrier which is a wireless medium into five RUs. Of course, the resource division example shown in FIG. 4 is merely an example, and for example, a number of RUs can be configured with different numbers of subcarriers. In addition, the wireless medium divided into RUs can include not only frequency resources but also spatial resources. A wireless communication device (e.g., an AP) can transmit frames to a number of terminal devices (e.g., a number of STAs) simultaneously by placing frames addressed to different terminal devices in each RU. The AP can include information indicating the division state of the wireless medium (resource allocation information) in the PHY header of a frame transmitted by the AP as common control information. Furthermore, the AP can include information indicating the RU in which the frame addressed to each STA is placed (resource unit assignment information) as unique control information in the PHY header of the frame transmitted by the AP itself.

[0049] Furthermore, multiple terminal devices (e.g., multiple STAs) can transmit frames simultaneously by placing frames in the assigned RUs and transmitting them. After receiving a frame (Trigger frame: TF) containing trigger information transmitted from the AP, multiple STAs can transmit frames after waiting for a predetermined period of time. Each STA can grasp the RU assigned to itself based on the information contained in the TF. Furthermore, each STA can acquire an RU by random access based on the TF.

[0050] The AP can simultaneously allocate multiple RUs to one STA. The multiple RUs can be configured with consecutive subcarriers or non-consecutive subcarriers. The AP can transmit one frame using the multiple RUs allocated to one STA, and can allocate multiple frames to different RUs for transmission. At least one of the multiple frames can be a frame including common control information for multiple terminal devices that transmit resource allocation information.

[0051] One STA can be assigned multiple RUs by the AP. The STA can transmit one frame using the assigned multiple RUs. Also, the STA can assign multiple frames to different RUs and transmit them using the assigned multiple RUs. The multiple frames can be frames of different frame types.

[0052] An AP can assign multiple AIDs to one STA. An AP can assign RUs to the multiple AIDs assigned to one STA. An AP can transmit different frames to the multiple AIDs assigned to one STA using the assigned RUs. The different frames can be frames of different frame types.

[0053] One STA can be assigned multiple AIDs by the AP. One STA can be assigned RUs for each of the multiple assigned AIDs. One STA recognizes all RUs assigned to the multiple AIDs assigned to the STA as RUs assigned to the STA itself, and can transmit one frame using the multiple assigned RUs. Also, one STA can transmit multiple frames using the multiple assigned RUs. At this time, the multiple frames can be transmitted including information indicating the AIDs associated with the assigned RUs.

[0054] Hereinafter, the base station device and the terminal device are collectively referred to as a wireless communication device or a communication device. Information exchanged when a wireless communication device communicates with another wireless communication device is also referred to as data. In other words, the wireless communication device includes the base station device and the terminal device.

[0055] The wireless communication device has either or both of a function for transmitting and receiving a PPDU. FIG. 1 is a diagram showing an example of a PPDU structure transmitted by a wireless communication device. A PPDU conforming to the IEEE802.11a / 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 IEEE802.11n 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 IEEE802.11ac standard is configured to include an L-STF, an L-LTF, an L-SIG, a VHT-SIG-A, a VHT-STF, a VHT-LTF, a VHT-SIG-B, and a part or all of a MAC frame. The PPDU conforming to the IEEE802.11ax standard is configured to include some or all of the following: L-STF, L-LTF, L-SIG, RL-SIG in which L-SIG is repeated over time, HE-SIG-A, HE-STF, HE-LTF, HE-SIG-B, and Data frames. The PPDU considered in IEEE802.11be is configured to include some or all of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, HET-LTF, and Data frames.

[0056] The L-STF, L-LTF, and L-SIG enclosed by dotted lines in Fig. 1 are configurations commonly used in the IEEE 802.11 standard (hereinafter, L-STF, L-LTF, and L-SIG are also collectively referred to as L-header). For example, a wireless communication device compatible with the IEEE 802.11a / b / g standard can properly receive an L-header in a PPDU compatible with the IEEE 802.11n / ac standard. A wireless communication device compatible with the IEEE 802.11a / b / g standard can receive a PPDU compatible with the IEEE 802.11n / ac standard by regarding it as a PPDU compatible with the IEEE 802.11a / b / g standard.

[0057] However, wireless communication devices that comply with the IEEE 802.11a / b / g standards cannot demodulate the PPDU that complies with the IEEE 802.11n / ac standards that follows the L-header, and therefore cannot demodulate information related to the transmitter address (TA: Transmitter Address), receiver address (RA: Receiver Address), and Duration / ID field used to set the NAV.

[0058] 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 to perform reception 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.

[0059] FIG. 2 is a diagram showing an example of a method of inserting Duration information into an L-SIG. In FIG. 2, a PPDU configuration corresponding to the IEEE802.11ac standard is shown as an example, but the PPDU configuration is not limited to this. A PPDU configuration corresponding to the IEEE802.11n standard, a PPDU configuration corresponding to the IEEE802.11ax standard, or a PPDU configuration considered in IEEE802.11be may also be used. TXTIME includes information on the length of the PPDU, aPreambleLength includes information on the length of the preamble (L-STF+L-LTF), and aPHYHeaderLength includes information on the length of the PHY header (L-SIG). L_LENGTH includes a Signal Extension, which is a virtual period set to achieve compatibility with the IEEE802.11 standard, and an N related to 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. The L-SIG Duration indicates information about the duration that is the sum of the duration of the PPDU including L_LENGTH and the duration of the Ack and SIFS that are expected to be transmitted from the destination wireless communication device in response to the PPDU.

[0060] 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 a 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. In the example shown in FIG. 3, L-SIG TXOP Protection using RTS / CTS is shown, but CTS-to-Self may also be used. Here, MAC Duration is a 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.

[0061] 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.

[0062] 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, the wireless communication device can interpret the PPDU including the L-SIG as a PPDU that complies with the IEEE802.11ax standard.

[0063] The wireless communication device can receive a part of a PPDU other than the PPDU (for example, a preamble, L-STF, L-LTF, PHY header, etc., defined by IEEE802.11) even during a PPDU reception operation (also referred to as a dual reception operation). When the wireless communication device detects a part of a PPDU other than the PPDU during a PPDU reception operation, the wireless communication device can update a destination address, a source address, and part or all of information related to the PPDU or DATA period.

[0064] Ack and BA can also be called responses (response frames). In addition, a probe response, an authentication response, and a connection response can also be called responses. [1. First embodiment]

[0065] The Multi-AP wireless communication system is composed of wireless communication systems provided by a plurality of access point devices. FIG. 5 is a diagram showing an example of the Multi-AP wireless communication system according to the present embodiment, which is an example composed of four systems, namely, wireless communication system 3-1, wireless communication system 3-2, wireless communication system 3-3, and wireless communication system 3-4. In the Multi-AP wireless communication system, in addition to the conventional transmission and reception of frames between one access point device and one or more station devices, it is also possible for a plurality of access point devices to cooperate with each other to transmit and receive frames to and from station devices. Basically, the communication areas (also called coverage, which in this example refers to 3-1, 3-2, 3-3, and 3-4) provided by each wireless communication system are configured to overlap (overlap). This example is an example in which the Multi-AP wireless communication system is composed of four wireless communication systems, but it is merely an example, and the system may be composed of a plurality of wireless communication systems other than four.

[0066] 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. The station devices 2-1, 2-12, 2-13, and 2-123 are collectively referred to as station device 2A (terminal device 2A) as devices connected (associated) with the access point device 1-1. The access point device 1-1 and the 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 work together 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 work together 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 device 1-1, access point device 1-2, and access point device 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, which is the connection destination.

[0067] 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. The station devices 2-2, 2-21, 2-23, and 2-213 are also collectively referred to as station device 2B (terminal device 2B) as devices connected (associated) with the access point device 1-2. The access point device 1-2 and the 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 device 1-2 and the access point device 1-1 work together 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 device 1-2 and the access point device 1-3 work together 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 device 1-2, access point device 1-1 and access point device 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, which is the connection destination.

[0068] 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. 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 the 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 work together 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 work together 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, which is the connection destination.

[0069] 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 in a state in which they can transmit and receive frames to and from each other. The station device 2-4 transmits and receives frames only to and from the access point device 1-4 to which it is connected.

[0070] The access point devices 1-1, 1-2, 1-3, and 1-4 constituting 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 called a Coordinator access point device (Coordinator AP) or Sharing access point device (Sharing AP), etc.) and plays a role of issuing instructions to and controlling the other access point devices, that is, child access point devices (child APs) (also called Coordinated access point device (Coordinated AP) or Shared access point device (Shared AP), etc.). A plurality of parent access point devices may be arranged in one Multi-AP wireless communication system to provide redundancy or to share roles.

[0071] Each access point device constituting the Multi-AP wireless communication system may relay a frame to be transmitted to a station device connected to another access point device, or a frame received from a station device. For example, a frame transmitted by an access point device 1-1 may be received by a station device 2-2 via an access point device 1-2. A frame transmitted by a station device 2-2 may be received by an access point device 1-1 via an access point device 2-1.

[0072] 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.

[0073] There are several methods for the above-mentioned cooperation between access point devices. A representative method is joint operation, in which several 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 can synchronize their timing to transmit the frame to station device 2-21, thereby achieving a gain.

[0074] Another representative method is coordinated operation, in which multiple access point devices cooperate by sharing each other's communication status, and adjust the usage of the wireless medium, so that 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 the access point device 1-1 and the access point device 1-2 do not overlap. As a result, for station device 2-12 and station device 2-21 located in a place where their communication areas (coverages) overlap, the access point device 1-1 can use frequency resource A for station device 2-12, and the 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.

[0075] 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.

[0076] An example of the format of a MAC Frame is shown in Figure 10. The MAC Frame here 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.

[0077] Although the wireless communication system 3-1, the wireless communication system 3-2, the wireless communication system 3-3, and the wireless communication system 3-4 form different BSSs, this does not necessarily mean that the ESSs (Extended Service Sets) are different. The ESS indicates a service set forming a LAN (Local Area Network). In other words, wireless communication devices belonging to the same ESS can be regarded as belonging to the same network from a higher layer. The BSSs are coupled via a DS (Distribution System) to form an ESS. Each of the wireless communication systems 3-1, 3-2, 3-3, and 3-4 can further include a plurality of wireless communication devices.

[0078] 6 is a diagram showing an example of the device configuration of wireless communication devices 1-1, 1-2, 1-3, 1-4, 2A, 2B, 2C, and 2D (hereinafter, collectively referred to as wireless communication device 10000-1). Wireless communication device 10000-1 includes an upper layer unit (upper layer processing step) 10001-1, an autonomous distributed control unit (autonomous distributed control step) 10002-1, a transmitting unit (transmitting step) 10003-1, a receiving unit (receiving step) 10004-1, and an antenna unit 10005-1.

[0079] The upper layer unit 10001-1 has a function of the MAC layer, is connected to other networks via a DS (Distribution System), and can notify the autonomous distributed control unit 10002-1 of traffic-related information. The traffic-related 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.

[0080] 7 is a diagram showing an example of the device configuration of the autonomous distributed control unit 10002-1. The autonomous distributed control unit 10002-1 includes a CCA unit (CCA step) 10002a-1, a backoff unit (backoff step) 10002b-1, and a transmission decision unit (transmission decision step) 10002c-1.

[0081] The CCA unit 10002a-1 can use either or both of information on the power of a signal received via a wireless resource and information on the received signal (including information after decoding) notified from the receiving unit 10004-1 to perform a state determination of the wireless resource (including a determination of whether the wireless resource 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 wireless resource.

[0082] 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 of a random backoff time set in 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.

[0083] The transmission decision unit 10002c-1 makes a transmission decision using either or both of the wireless resource status decision information and the back-off counter value. For example, when the wireless resource status decision information indicates "idle" and the back-off counter value is 0, the transmission decision unit 10003-1 can be notified of the transmission decision information. Also, when the wireless resource status decision information indicates "idle," the transmission decision unit 10003-1 can be notified of the transmission decision information.

[0084] 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 a function of generating a physical layer frame (PPDU) based on transmission decision information notified from the transmission decision unit 10002c-1. The physical layer frame generating unit 10003a-1 performs error correction coding, modulation, precoding filter multiplication, etc. on the transmission frame sent from the upper layer. The physical layer frame generating unit 10003a-1 outputs the generated physical layer frame to the wireless transmitting unit 10003b-1.

[0085] The physical layer frame generator 10003a-1 applies error correction coding to the information bits input from the MAC layer, but the unit (coding block length) for applying error correction coding is not limited to any particular one. 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, apply error correction coding to each of them, and generate a plurality of coding blocks. When forming the coding blocks, it is also possible to insert dummy bits into the information bit sequence input from the MAC layer.

[0086] The frame generated by the physical layer frame generator 10003a-1 includes control information. The 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 frame generated by the physical layer frame generator 10003a-1 also includes a trigger frame that instructs the wireless communication device, which is the destination terminal, to transmit a frame. The trigger frame includes information indicating the RU to be used when the wireless communication device instructed to transmit the frame transmits the frame.

[0087] 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, and the like.

[0088] The receiving unit 10004-1 includes a wireless receiving unit (wireless receiving step) 10004a-1 and a signal demodulating unit (signal demodulating step) 10004b-1. The receiving unit 10004-1 generates information about the 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 the information about the received signal power and the information about the received signal.

[0089] The wireless receiver 10004a-1 has a function of converting an RF 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 receiver 10004a-1 includes frequency conversion from the RF band to the baseband, filtering, and analog-to-digital conversion.

[0090] The signal demodulation unit 10004b-1 has a function of demodulating the physical layer signal generated by the wireless receiving unit 10004a-1. The processing performed by the signal demodulation unit 10004b-1 includes channel equalization, demapping, error correction decoding, and the like. The signal demodulation unit 10004b-1 can extract, 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. The signal demodulation unit 10004b-1 can extract any one 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.

[0091] The antenna unit 10005-1 has a function of transmitting a radio frequency signal generated by the wireless transmission unit 10003b-1 to the other wireless device 10000-1 into wireless space, and also has a function of receiving a radio frequency signal transmitted from the other wireless device 10000-1.

[0092] The wireless communication device 10000-1 can include information indicating the period during which the wireless medium is used by the wireless communication device 10000-1 in the PHY header or MAC header of a frame to be transmitted, thereby making it possible for the wireless communication devices around the wireless communication device 10000-1 to set a NAV for that period only. For example, the wireless communication device 10000-1 can include information indicating that period in the Duration / ID field or Length field of the frame to be transmitted. The NAV period set in the wireless communication devices around the wireless communication device 10000-1 is called the TXOP period (or simply called TXOP, also called transmission opportunity) acquired by the wireless communication device 10000-1. The wireless communication device 10000-1 that has acquired the TXOP is called a TXOP acquirer (TXOP holder). The frame type of the frame that the wireless communication device 10000-1 transmits to acquire a TXOP is not limited to any particular type, and may be a control frame (for example, an RTS frame or a CTS-to-self frame) or a data frame.

[0093] 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. If the wireless communication device 1-1 is a TXOP holder, the wireless communication device 1-1 can transmit frames to the wireless communication device 2A during the 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.

[0094] 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 (Band), such as a communication band (e.g., Transmission bandwidth) over which frames will actually be transmitted.

[0095] The wireless communication device that instructs the wireless communication device 1-1 to transmit a frame during the period of the TXOP acquired by the wireless communication device 1-1 is not necessarily limited to the wireless communication device connected to the wireless communication device itself. For example, the wireless communication device can instruct a wireless communication device not connected to the wireless communication device itself to transmit a frame in order to make the wireless communication device in the vicinity of the wireless communication device itself transmit a management frame such as a Reassociation frame or a control frame such as an RTS / CTS frame.

[0096] In addition, we will also explain TXOP in EDCA, which is a data transmission method different from DCF. The IEEE802.11e standard is related to EDCA, and specifies TXOP from the viewpoint of QoS (Quality of Service) guarantee for various services such as video transmission and VoIP. Services are roughly 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 value of CW, CWmin, the maximum value, AIFS (Arbitration IFS), which is a type of IFS, and TXOP limit, which is the upper limit of TXOP, and the values ​​are set to give a difference in priority. For example, the CWmin, CWmax, and AIFS of VO, which has the highest priority for voice transmission, can be set to relatively small values ​​compared to other access categories, enabling data transmission with priority over other access categories. For example, in a VI where the amount of data transmitted is relatively large for video transmission, by setting the TXOP limit large, it is possible to obtain a longer TXOP than other access categories.In this way, the values ​​of the four parameters for each access category are adjusted to guarantee QoS according to various services.

[0097] In this embodiment, the signal demodulation unit 10004b-1 of the station device can perform decoding processing in the physical layer on the received signal and perform error detection. Here, the decoding processing includes decoding processing on the error correction code applied to the received signal. Here, the error detection includes error detection using an error detection code (e.g., a cyclic redundancy check (CRC) code) that is previously added 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 in the physical layer can be applied to each coding block.

[0098] The upper layer unit 10001-1 receives the result of decoding the physical layer by the signal demodulation unit 10004b-1 and restores the MAC layer signal. Then, the MAC layer performs error detection and judges whether the MAC layer signal transmitted by the station device that is the source of the received frame has been correctly restored.

[0099] The wireless communication device may be a multi-link device (MLD: Multi Link Device) capable of multi-link communication. An access point device that supports MLD is called an MLD access point device, and a station device that supports MLD is called an MLD station device. In addition, MLD access point devices and MLD station devices are collectively called MLD wireless communication devices.

[0100] The MLD access point device 20000-1 and the MLD station device 30000-1 will be described with reference to Fig. 16. The MLD wireless communication device is composed of a plurality of sub-wireless communication devices corresponding to the frequency bands (or channels, or sub-channels) of each link (also called physical layer link) constituting the 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, 20000-4), but the number of sub-access point devices is 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, 30000-4), but the number of substation devices is any number greater than or equal to one. The sub-wireless communication device (sub-access point device, sub-station device, etc.) may be configured as a part of the circuitry within the wireless communication device, and may be called a sub-wireless communication unit (sub-access point unit, sub-station unit).

[0101] In Fig. 16, for the sake of explanation, a plurality of sub-wireless communication devices are logically shown as separate blocks (squares), but they may be physically configured as one wireless communication device. Alternatively, they may be physically configured as separate sub-wireless communication devices, in which case each sub-access point device transmits and receives necessary information via connections 9-1 and 9-2, and each substation device transmits and receives necessary information via connections 9-3 and 9-4. In this embodiment, the MLD wireless communication device is physically configured as one wireless communication device (10000-1), and the configuration is the same as that described above with reference to Figs. 6 and 7.

[0102] The number of sub-access point devices included in one MLD access point device and the number of substation devices included in one MLD station device may vary depending on the grade, class, and capabilities of each MLD wireless communication device. The higher the grade, class, and capabilities of an MLD wireless communication device, the more sub-wireless communication devices (sub-access point devices, substation devices) it may have. In other words, for each MLD wireless communication device located in one wireless communication system, the number of sub-wireless communication devices (sub-access point devices, substation devices) that make up each MLD wireless communication device may vary depending on the grade, class, and capabilities, and these numbers do not have to be the same.

[0103] 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 this and may be any number. In the description of this embodiment, the carrier frequency of link 1 is 2.4 GHz band, the carrier frequency of link 2 is 5 GHz band, and the carrier frequency of link 3 is 6 GHz band. However, the frequency used by each link can be arbitrarily set from the 2.4 GHz band, 5 GHz band, 6 GHz band, 60 GHz band, and other frequency bands, channels, and sub-channels supported by the wireless communication system, and may change according to the laws and regulations of each country.

[0104] An example of a wireless communication system including a station device and an access point device according to this embodiment will be described with reference to Fig. 11. Fig. 11 shows the access point device 1-1, the station devices 2-1, 2-12, 2-13, and 2-123 connected to the access point device 1-1, the access point devices 1-2 and 1-3 that cooperate with the access point device 1-1, and the access point device 1-4 that does not cooperate with the access point device 1-1, as shown in Fig. 5. In addition, the station devices 2-2, 2-3, 2-4, and 2-34 are also added for supplementary explanation. Also, it is assumed that a frame 11-11 is transmitted from the access point device 1-1 to the station device 2-123, a frame 11-12 is transmitted from the station device 2-123 to the access point device 1-1, a frame 11-21 is transmitted from the access point device 1-2 to the station device 2-123, a frame 11-22 is transmitted from the station device 2-123 to the access point device 1-2, a frame 11-31 is transmitted from the access point device 1-3 to the station device 2-123, and a frame 11-32 is transmitted from the station device 2-123 to the access point device 1-3. Here, it is assumed that the access point devices 1-1, 1-2, 1-3, and 1-4 are access point devices that support cooperation between the access point devices. However, for example, when the station device 2A connected to the access point device 1-1 is the target, the communication area (coverage) of the access point device 1-4 does not overlap with that of the access point device 1-1. Therefore, in this embodiment, a case will be described in which the access point device 1-4 cannot communicate with the station device 2A in cooperation with the access point device 1-1.

[0105] Also, if the access point device 1-4 does not support cooperation between access point devices, the access point device 1-4 cannot cooperate with other access point devices. For example, although a station 2-34 connected to the access point device 1-3 is located within the communication area (coverage) of the access point device 1-4, the access point devices 1-3 and 1-4 communicate only with the access point device 1-3.

[0106] The method of cooperation between the access point devices is not limited, and as an example, the above-mentioned joint operation, coordinated operation, or the like may be used.

[0107] When performing cooperative operations between access point devices, such as joint operations and coordinated operations, it is useful to report received signal quality information (also called received signal statistical information) based on measurements of frame reception conditions from surrounding access point devices observed on the station device side to the access point device side. Furthermore, if the received signal quality information includes information based on measurements of frame reception conditions from other station devices (Reported STAs) observed on the reporting station device (Reporting STA), this contributes to better joint operations and coordinated operations.

[0108] The reception signal quality information, frame reception statistical information, frame transmission statistical information, traffic requirement information, etc., described later, are referred to as 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.). The inter-access point device cooperation information may include any one of reception signal quality information, frame reception statistical information, frame transmission statistical information, and traffic requirement information.

[0109] The frame reception statistical information may be, for example, a part or all of information such as the bit error rate (BER), frame error rate (FER), block error rate (BLER), number of received data frames, number of received management frames, etc. of the frame received by the station device. Also, without being limited to these pieces of information, information showing frame reception statistics may be used. The frame transmission statistical information may be, for example, a part or all of information such as the frame collision rate, retransmission rate, CW time, medium occupancy rate, wireless medium busy rate, wireless medium idle rate, channel load, etc., when the station device transmits a frame. Without being limited to these examples, any statistical information related to frame transmission and reception may be used.

[0110] Traffic requirement (which may also be referred to as Traffic Specification, Traffic Classification, QoS Characteristics, etc.) information is the traffic requirements 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, as examples.

[0111] The received signal quality value to be included in the access point device cooperation information may be, for example, 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., but is not limited to these and may be any value or index that evaluates the received signal quality.

[0112] The inter-access point device cooperation information reported by the station device (station device 2-123 in this example) to the access point device (access point device 1-1 in this example) may be shared (transmitted) to the Coordinator access point device in addition to the access point device 1-1. Information included in the received signal quality information can also be used to determine an access point device other than the access point device 1-1, which is the connection destination (association destination), that has a large influence from the viewpoint of the station device 2-123. According to the reported contents, the access point device 1-1 (or the Coordinator access point device) may determine the inter-access point device cooperation instruction information (also referred to as inter-access point device cooperation instruction information) indicating with which other access point device the access point device 1-1 will cooperate and in what way. It is effective for the access point device side and the station device 2-123 to transmit and receive frames in the determined cooperative operation. An example of the above-mentioned "highly influential access point device" may be an access point device with a large RSSI measured by the station device 2-123, which is an example of information included in the received signal quality information. In other words, an access point device with a large RSSI other than the access point device 1-1 may be an interference factor in frame transmission and reception between the access point device 1-1 and the station device 2-123, and it is effective to make it a target of cooperative operation. It goes without saying that the judgment index for a "highly influential access point device" is not limited to RSSI.

[0113] A specific example will be described using RSSI as an example of information included in the received signal quality information. For example, station device 2-123 is located at a place where the communication areas (coverages) of wireless communication systems 3-1, 3-2, and 3-3 overlap, and is located outside the communication area (coverage) of wireless communication system 1-4. Station device 2-123 measures the RSSI of a frame transmitted from each access point device, and reports to access point device 1-1, which is the communication partner, that the RSSI value of access point device 1-1 is RSSI_1, the RSSI value of access point device 1-2 is RSSI_2, the RSSI value of access point device 1-3 is RSSI_3, and the RSSI value of access point device 1-4 is RSSI_4. For example, it is assumed that RSSI_1, RSSI_2, and RSSI_3 are the same value, and RSSI_4 is an unmeasurable value. In communication with station device 2-123, access point device 1-1 (or Coordinator access point device) may determine that access point devices 1-2 and 1-3, which have relatively large reported RSSIs, are candidates for cooperative operation between access point devices, and may determine that access point device 1-4, whose RSSI could not be measured because it is outside the communication area, is not a candidate for cooperative operation between access point devices, and may perform cooperative operation between access point devices depending on the results of these determinations.

[0114] As described above, the access point device 1-1 (or the Coordinator access point device) generates inter-access point device cooperation instruction information. When the access point devices are capable of wireless communication with each other, the access point devices may directly transmit and receive a frame including the inter-access point device cooperation instruction information. As an example, when the access point device 1-1 (or the Coordinator access point device) is capable of wireless communication with a target access point device (access point devices 1-2 and 1-3 in this example) for inter-access point device cooperation operation, the access point device 1-1 (or the Coordinator access point device) may directly transmit and receive a wireless frame including the inter-access point device cooperation instruction information with the target access point device. For example, the access point device 1-1 transmits a frame including the inter-access point device cooperation instruction information to the access point device 1-2 and the access point device 1-3. The access point devices 1-1, 1-2, and 1-3 may cooperate with each other according to the shared inter-access point device cooperation instruction information.

[0115] 11, the access point devices 1-2 and 1-3 are not located within the communication area (coverage) 3-1 of the access point device 1-1. In such a case, the access point devices may be connected to each other by a wired connection such as Ethernet (registered trademark), and the access point device 1-1 may transmit inter-access point device cooperation instruction information to the access point devices 1-2 and 1-3 by wired communication.

[0116] Another method of transmitting the access point apparatus cooperation instruction information is via a station device. For example, the access point apparatus 1-1 transmits the access point apparatus cooperation instruction information to the station device 2-123 by including the access point apparatus cooperation instruction information in a frame 11-11. The station device 2-123 that receives the frame 11-11 may transmit the access point apparatus cooperation instruction information to the access point apparatus 1-2 by including the access point apparatus cooperation instruction information in a frame 11-21. That is, the station device 2-123 may relay the access point apparatus cooperation instruction information received from the access point apparatus 1-1 to the access point apparatus 1-2. Similarly, the station device 2-123 that receives the frame 11-11 may transmit the access point apparatus cooperation instruction information to the access point apparatus 1-3 by including the access point apparatus cooperation instruction information in a frame 11-31. That is, the station device 2-123 may relay the access point apparatus cooperation instruction information received from the access point apparatus 1-1 to the access point apparatus 1-3. In this manner, the station device 2-123 may operate as a relay device that relays inter-access point device cooperation instruction information received from an access point device to a plurality of access point devices other than the access point device.

[0117] The inter-access point device cooperation instruction information may be transmitted to the target access point devices (access point devices 1-2 and 1-3 in this example) in a unicast frame (Individually addressed frame), a multicast frame (Multicast frame, Group addressed frame), or a broadcast frame. The inter-access point device cooperation instruction information may be transmitted to the target access point devices in the inter-access point device cooperation operation.

[0118] The access point devices (in this example, the access point devices 1-1, 1-2, and 1-3) that have shared the inter-access point device cooperation instruction information may use the inter-access point cooperation instruction information for cooperative operation between the access point devices.

[0119] The inter-access point apparatus cooperation instruction information includes information related to a method of cooperation between access point apparatuses (also referred to as an operation mode, and specifies an operation mode such as joint operation or coordinated operation). When joint operation is specified, information indicating an operation mode such as Joint Tx (joint transmission), Joint OFDMA, or Joint BF (Beam Forming) may be included. When coordinated operation is specified, information indicating an operation mode such as Coordinated OFDMA, Coordinated SR (Spatial Reuse), Coordinated BF (Beam Forming), Coordinated TXOP Sharing, or Coordinated TDMA (Time Division Multiple Access) may be included.

[0120] The inter-access point device cooperation instruction information may include a list of access point devices that cooperate with each other. In the example of Fig. 11, since the access point devices 1-1, 1-2, and 1-3 cooperate with each other for the station device 2-123, the list of access point devices that cooperate with each other may include information related to the access point devices 1-1, 1-2, and 1-3 (identification information such as BSSID and individual identification information corresponding thereto).

[0121] The inter-access point device cooperation instruction information may include information for time synchronization of the access point devices. For example, the inter-access point device cooperation instruction information may include a time synchronization function (TSF) of the access point devices and a TSF offset (TSF offset) between the access point devices. For example, the inter-access point device cooperation instruction information may include the TSF of the access point device 1-1 in order for the access point devices 1-1, 1-2, and 1-3 to transmit frames in time synchronization. The access point devices 1-2 and 1-3 may calculate the offset of their respective TSFs based on the TSF of the access point device 1-1.

[0122] 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. A beacon frame, which is an example of a wireless management frame, is a frame that includes the capability information of an access point device, and is not transmitted by an access point device to a specific station device only, but is broadcast to surrounding wireless communication devices. Therefore, a beacon frame is suitable for grasping the standard (normal) transmission characteristics and signal quality of an access point device.

[0123] In addition, a station device that creates received signal quality information may measure frames transmitted and received by a surrounding access point device between itself and other specific station devices in order to grasp communication conditions other than beacon frames. This means that unicast frames (individually addressed frames) and multicast frames (group addressed frames) may also be included in the measurement targets.

[0124] Furthermore, in the case where a station device that creates the received signal quality information measures frames such as unicast frames or multicast frames to which beamforming is applied 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 creates the received signal quality information may report the received signal quality information generated by taking into account the received signal quality of the frame unicast (or multicast) to the other specific station device to the access point device to which it is connected.

[0125] 13 illustrates an example of primitives exchanged within a wireless communication device and frames exchanged between wireless communication devices, taking as an example a case where a station device measures the received signal quality of a nearby access point device. Here, as an example, the primitive name is MEASURESTA. In order to check the status of frames received from nearby access point devices, the station device issues a primitive MLME-MEASURESTA.request13-1 from the SME to the MLME instructing it. Upon receiving the instruction, the MLME instructs the MAC layer and PHY layer to receive frames transmitted by nearby access point devices and measure the received signal quality.

[0126] The station device transmits the access point device cooperation information including the reception signal quality information of the frame received from the surrounding access point device in a Report frame 13-2, and the access point device receives the information. The MLME of the access point device reports the access point device cooperation information included in the Report frame 13-2 to the SME in Primitive MLME-MEASURESTA.indication 13-3, and the reported content can also be used by the upper layer. Here, the upper layer means a layer above the MAC layer, and the upper layer also includes the application layer. This means that the application layer of the access point device can use the access point device cooperation information including the reception signal quality information of the surrounding access point device acquired by the station device. In addition, the access point device can share (transmit) the access point device cooperation information to a Coordinator access point device in the Multi-AP wireless communication system.

[0127] The SME of the access point device, or an upper layer of the access point device, or a Coordinator access point device in a Multi-AP wireless communication system may use the received access point device coordination information to determine which other access point devices the access point device will cooperate with and in what manner.

[0128] As an example, the MLME of the station device may report the inter-access point device cooperation information included in the Report frame 13-2 to the SME in Primitive MLME-MEASURESTA.confirm 13-4. The reported content can also be used by higher layers. In other words, the station device can use the received signal quality information of the surrounding access point devices that it has acquired and other information included in the inter-access point device cooperation information (frame reception statistical information, frame transmission statistical information, etc.) in its own higher layer.

[0129] The SME of the station device or an upper layer of the station device may change the traffic requirement information according to the received inter-access point device cooperation information. For example, by referring to frame transmission statistical information, if the wireless medium busy rate is high, the average throughput value of the traffic requirement information may be reduced, assuming that the wireless communication environment is poor. In addition, the values ​​included in the traffic requirement information may be changed according to the values ​​included in the reception signal quality information, frame reception statistical information, and frame transmission statistical information, which are included in the inter-access point device cooperation information.

[0130] Although it has been described above that the station device transmits the Report frame 13-2 to the access point device of the connection destination (association destination) after the station device connects (associates) with the access point device, the Report frame 13-2 may be transmitted to an access point device other than the connection destination, or the Report frame 13-2 may be broadcast without limiting the destination. Also, the station device may transmit the Report frame 13-2 before connecting (associating) with the access point device.

[0131] The Report frame 13-2 is a frame that the station device transmits voluntarily without being solicited (also called triggered) by the access point device, and a frame transmitted from the station device in this manner is also called an unsolicited frame. This method (also called a method or mode) is also called an unsolicited mode.

[0132] While Fig. 13 describes a case where a station device transmits cooperation information between access point devices using an unsolicited frame, Fig. 14 describes a case where a station device transmits cooperation information between access point devices using a solicited frame in which the station device is solicited (also called a trigger) by an access point device. This method (also called a technique or mode) is called a solicited mode.

[0133] FIG. 14 illustrates an example of Primitives exchanged within a wireless communication device and frames exchanged between wireless communication devices as an example of a case where a station device receives a request from an access point device and measures the reception signal quality of a neighboring access point device. Here, the name of the Primitive is MEASUREAP as an example. In the access point device, in order to request cooperation information between access point devices (including reception signal quality information and the like) from the station device, the SME issues Primitive MLME-MEASUREAP.request 14-1 to the MLME to instruct the station device. Upon receiving the instruction, the MLME transmits Report Request frame 14-2 to the station device, which receives it. The station device issues MLME-MEASUREAP.indication 14-3 from the MLME to the SME, and the SME issues MLME-MEASUREAP.response 14-4 to the MLME. This corresponds to instructing the MAC layer and PHY layer to receive frames transmitted by neighboring access point devices and measure reception signal quality.

[0134] The station device transmits the access point device cooperation information including the reception signal quality information in a Report Response frame 14-5, and the access point device receives it. The MLME of the access point device reports the access point device cooperation information (including the reception signal quality information) included in the Report Response frame 14-5 to the SME in Primitive MLME-MEASUREAP.confirm 14-6, and the reported content can also be used by the upper layer. Here, the upper layer means a layer above the MAC layer, and the upper layer also includes the application layer. This means that the application layer of the access point device can use the access point device cooperation information including the reception signal quality information of the surrounding access point devices acquired by the station device. In addition, the access point device can share (transmit) the access point device cooperation information to a Coordinator access point device in the Multi-AP wireless communication system.

[0135] The station device can extract the access point device cooperation information reported to the access point device in the Report Response frame 14-5 to the SME of the station device or to a higher layer of the station device. Here, the Primitive name is set to MEASURESELF as an example. The SME sends MLME-MEASURESELF.request14-7 to the MLME. The MLME reports the contents equivalent to the access point device cooperation information included in the Report Response frame 14-5, or a part of it, to the SME in Primitive MLME-MEASURESELF.confirm, and the reported information can also be used by higher layers.

[0136] Although it has been described above that the station device transmits the Report Response frame 14-5 to the access point device to which it is connected (associated), it may also be transmitted to an access point device other than the access point device to which it is connected, or may be broadcast without limiting the destination. Also, the access point device may transmit the Report Request frame 14-2 to an unassociated station device (Unassociated STA), and in response, the station device may transmit the Report Response frame 14-5 to the access point device. In the case of an Unassociated STA, the Report Response frame 14-5 may also be broadcast without limiting the destination.

[0137] The SME of the access point device, or an upper layer of the access point device, or a Coordinator access point device in a Multi-AP wireless communication system may use the access point device coordination information to determine which other access point devices the access point device will cooperate with and in what manner.

[0138] The inter-access point device cooperation information created by the station device may include information other than the reception signal quality. For example, it may include some or all of the frame reception statistical information and the frame transmission statistical information as statistical information related to the frame transmission and reception of the station device. Examples of the frame reception statistical information include the BER (Bit Error Rate), FER (Frame Error Rate), BLER (Block Error Rate), the number of received data frames, the number of received management frames, and the like of the frames received by the station device. Examples of the frame transmission statistical information include the frame collision rate, retransmission rate, CW time, medium occupancy rate, medium busy rate, medium idle rate, channel load, and the like when transmitting frames from the station device. The information is not limited to these examples, and may be any statistical information related to the frame transmission and reception.

[0139] The primitive MLME-MEASURESTA.request13-1 in FIG. 13 and the primitive MLME-MEASUREAP.response14-4 in FIG. 14 issued by the station device from the SME to the MLME can include information from an upper layer. These primitives may include traffic requirement values ​​of an application operating in the application layer. For example, if the application is a video playback application, information indicating traffic requirement information required by the application, such as average throughput, maximum throughput, minimum throughput, acceptable frame error rate, acceptable delay amount, and acceptable jitter value, required for video playback, may be included. Note that the traffic requirement information may be included in the inter-access point device cooperation information.

[0140] Fig. 13 shows an example of a primitive sequence in unsolicited mode, but not all primitives are necessarily executed, and additional primitives may be executed. Fig. 14 shows an example of a primitive sequence in solicited mode, but not all primitives are necessarily executed, and additional primitives may be executed. The verbs "request", "confirm", "indication", and "response" at the end of the primitive names may differ from those shown in Figs. 13 and 14.

[0141] Using the frame transmission and reception diagram of FIG. 12, an example will be described in which a station device measures the received signal quality from the RSSI of a beacon frame from a surrounding access point device.

[0142] Here, the measurement target time is t1, and the measurement target time may be a fixed value, a variable value, or may be determined by negotiation at the time of association. The measurement target time t1 may be set in the MIB. The measurement target time t1 may be set by a Primitive. In the case of the unsolicited mode, in the station device in FIG. 13, the SME issues Primitive MLME-MEASURESTA.request13-1 to the MLME to indicate the measurement target time t1. In the case of the solicited mode, in the access point device in FIG. 14, the SME issues Primitive MLME-MEASUREAP.request14-1 to the MLME, and indicates the measurement target time t1 to the MLME of the station device using Report Request frame14-2 transmitted in response to the Primitive MLME-MEASUREAP.request14-1. In the same manner as in the method of determining the measurement target period t1 described above, parameters related to the reception signal quality measurement, such as the frame type to be measured (beacon frame, unicast frame, multicast frame, management frame, data frame, control frame, etc.) and the number of frames, may be determined.

[0143] In Fig. 12, only the minimum number of frames necessary for explanation are shown, but in reality, other frames may be transmitted and received. It is assumed that the measurement target time t1 is specified, but the frame type and the number of frames may be used as other parameters. It is assumed that the wireless LAN access point device 1-1 transmits beacon frames 12-11, 12-12, 12-13, and 12-14, the wireless LAN access point device 1-2 transmits beacon frames 12-21, 12-22, 12-23, and 12-24, the wireless LAN access point device 1-3 transmits beacon frames 12-31, 12-32, 12-33, and 12-34, and the wireless LAN access point device 1-4 transmits frames 12-41, 12-42, 12-43, and 12-44. During the designated measurement time t1, the wireless LAN station device 2-123 calculates the RSSI as the reception signal quality information of the wireless LAN access point device 1-1 from the beacon frames 12-11, 12-12, 12-13, and 12-14, calculates the RSSI as the reception signal quality information of the wireless LAN access point device 1-2 from the beacon frames 12-21, 12-22, 12-23, and 12-24, calculates the RSSI as the reception signal quality information of the wireless LAN access point device 1-3 from the beacon frames 12-31, 12-32, 12-33, and 12-34, and calculates the RSSI as the reception signal quality information of the wireless LAN access point device 1-4 from the beacon frames 12-41, 12-42, 12-43, and 12-44. The average value, maximum value, minimum value, etc. in the measurement time t1 are used to calculate the RSSI as the reception signal quality information.

[0144] The reception signal quality information may be generated from all frames received during the period t1 as frames to be measured, or may be generated from some of the frames. For example, when generating reception signal quality information for the access point device 1-3, all of the frames 12-31, 12-32, 12-33, and 12-34 may be used, or only the frames 12-31 and 12-32 may be used as some of the frames. Although FIG. 12 shows only the beacon frames being broadcast as the targets for generating reception signal quality information, other frame types, such as unicast frames (individually addressed frames), broadcast frames, and multicast frames (group addressed frames), may be used as measurement targets depending on the negotiation, MIB, and primitive during the association described above.

[0145] The station device 2-123 reports the measurement result of the reception signal quality of the surrounding wireless LAN access point device at the measurement target time t1 to the access point device in a Report frame 12-51 (also called a Report Response frame 12-51). The frame 12-51 may be unicast (Individually addressed) to only the connection destination (association destination) access point device 1-1. The access point device cooperation information included in the Report frame 12-51 may be shared from the connection destination (association destination) access point device 1-1 to the Coordinator access point device. The Report frame 12-51 may be broadcast (Broadcast) or multicast (Multicast, Group addressed) so that it can be received by other access point devices. The wireless LAN access point device 1-1 (or a Coordinator access point device) may grasp the status of the access point devices around the station device 2-123 from the access point coordination information indicated in Report frame 12-51, and determine how to cooperate with other access point devices to communicate with the station device 2-123.

[0146] An example of the configuration of a Report frame 12-51 (also referred to as a Report Response frame 12-51) transmitted by the station device 2-123 is shown in Fig. 15. Note that the PHY header, MAC header, etc. are omitted. The Report frame 12-51 includes access point cooperation information. The access point cooperation information may include at least one of received signal quality information, received frame statistical information, transmitted frame statistical information, traffic requirement information, etc.

[0147] In the case of the wireless communication system shown in FIG. 11, the station device 2-123 can receive frames from the access point devices 1-1, 1-2, and 1-3, and the Report frame 12-51 includes the measurement results of the access points 1-1, 1-2, and 1-3. On the other hand, the station device 2-123 cannot receive frames from the access point device 1-4, so the Report frame 12-51 does not need to include the measurement results of the access point 1-4. The received signal quality information is information related to the signal quality of frames transmitted from the access point devices around the station device 2-123, and includes information such as RSSI, SNR, SNIR, and CQI, and the identification information may use part or all of the information such as the corresponding BSSID and SSID as information for identifying the access point device. For example, the received signal quality information 1 corresponds to the received signal quality information of the access point device 1-1, the received signal quality information 2 corresponds to the access point device 1-2, and the received signal quality information 3 corresponds to the received signal quality information of the access point device 1-3. Information about the access point apparatus 1-1 to which the station apparatus 2-123 is connected (associated) may or may not be included in the inter-access point cooperation information.

[0148] As an example, in the inter-access point cooperation information, the received signal quality information of each access point device may be arranged in the order in which the station device judges the signal quality to be good or in the order in which the access point device is recommended as a cooperation destination. In the example of Fig. 15, the station device may arrange the received signal quality information 1, the received signal quality information 2, and the received signal quality information 3 in order of good received signal quality values ​​or the order in which the access point device is preferred as a cooperation destination, or the order may be reversed. However, it is not necessary to arrange the received signal quality information according to the station device's standards, and the access point device that receives the Report frame 12-51 may judge the signal quality of each access point device according to the access point device's standards.

[0149] A difference may be provided in the contents of the inter-access point apparatus cooperation information included in the Report frame 12-51 (also referred to as the Report Response frame 12-51) between the solicited mode and the unsolicited mode. For example, traffic requirement information may be included in the unsolicited mode, but not in the solicited mode. For example, traffic requirement information may not be included in the unsolicited mode, but traffic requirement information may be included in the solicited mode. The information that is the difference is not limited to traffic requirement information, and may be other information (received signal quality information, received frame statistical information, transmitted frame statistical information, etc.).

[0150] So far, we have explained that in a Multi-AP wireless communication system, a station device measures the signal quality of frames transmitted from surrounding access point devices and reports the results to the access point device, and the access point device determines the combination of access point devices that will operate in cooperation with each other based on the contents of the report.

[0151] When the station device is an MLD, the signal quality of each of a plurality of frequencies (multi-links) may be measured. An example of the configuration of the Report frame12-51 (also called the Report Response frame12-51) is shown in FIG. 17. The cooperation information between the access point devices is composed of a plurality of link quality information. The link quality information 1 is composed of information on the link 1 (for example, the frequency is 2.4 GHz band), the link quality information 2 is composed of information on the link 2 (for example, the frequency is 5 GHz band), the link quality information 3 is composed of information on the link 3 (for example, the frequency is 6 GHz band), and so on, which may be used by the MLD. Each link quality information is composed of identification information, received signal quality information, received frame statistical information, transmitted frame statistical information, traffic requirement information, and so on, but does not necessarily need to include all of the information. The identification information here is information for identifying the link (such as Link ID).

[0152] In FIG. 13, when the SME of the station device issues Primitive MLME-MEASURESTA.request to request the MLME to perform measurement, the MLME creates link quality information for multiple frequencies (multi-links) constituting the MLD or multiple frequencies (multi-links) that may be used in the MLD, and reports it to the access point device to which it is connected in Report frame 13-2. In addition, the content equivalent to the inter-access point device cooperation information included in Report frame 13-2, or a part of it, is reported to the SME in Primitive MLME-MEASURESTA.confirm, and the reported information can also be used by the upper layer. Here, the upper layer means a layer above the MAC layer, and includes the application layer. The upper layer may use the link quality information included in the received inter-access point device cooperation information to determine which application is to be mapped to which link, and which TID (Traffic ID) is to be mapped to which link (frequency) (TID to Link Mapping). The upper layer may use the received link quality information for cooperation between the access point devices.

[0153] Each application can select a link according to its traffic requirements for communication. For example, assume that the communication conditions of link 1 are the best, followed by link 2 and link 3 in order of signal quality. If the desired bit rate of each application is highest for application 1, followed by application 2 and application 3 in order of bit rate, application 1 can be mapped to link 1, application 2 to link 2, and application 3 to link 3, respectively, thereby optimizing the operation of all applications appropriately.

[0154] As another application, the measurement target can be a nearby station device instead of a nearby access point device. If the measurement is expanded so that a station device measures the signal quality of a frame transmitted from another station device, the station device can use the measurement to select and determine the most suitable other station device for P2P communication, TDLS (Tunneled Direct Link Setup) communication, etc., which are communications between station devices.

[0155] [2. Common to all embodiments]

[0156] The communication device according to the present invention can communicate in a frequency band (frequency spectrum) called an unlicensed band, which does not require permission to use from a country or region, but the available frequency band is not limited to this. The communication device according to the present invention can also be effective in a frequency band called a white band (for example, a frequency band allocated for television broadcasting but unused in some regions) that is not actually used for the purpose of preventing interference between frequencies even though permission to use the band for a specific service is given by a country or region, and in a shared spectrum (shared frequency band) that is expected to be shared by multiple operators.

[0157] The program that operates in the wireless communication device according to the present invention is a program that controls the CPU, etc. (a program that makes a computer function) so as to realize the functions of the above-mentioned embodiments of the present invention. Information handled by these devices is temporarily stored in the RAM during processing, and then stored in various ROMs or HDDs, and is read, modified, and written by the CPU as necessary. The recording medium that stores the program may be any of semiconductor media (e.g., ROM, non-volatile memory card, etc.), optical recording media (e.g., DVD, MO, MD, CD, BD, etc.), magnetic recording media (e.g., magnetic tape, flexible disk, etc.), etc. In addition, not only the functions of the above-mentioned embodiments are realized by executing the loaded program, but also the functions of the present invention may be realized by processing in cooperation with an operating system or other application programs, etc. based on instructions from the program.

[0158] In addition, when distributing the program on the market, the program can be stored in a portable recording medium and distributed, 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. In addition, a part or all of the communication device in the above-mentioned embodiment 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 a 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.

[0159] In addition, 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 appears due to the advancement of semiconductor technology, it is also possible to use an integrated circuit based on that technology.

[0160] The present invention is not limited to the above-mentioned embodiment. The wireless communication device of the present invention is not limited to application to a mobile station device, but can be applied to stationary or non-movable electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning and washing machines, air conditioners, office equipment, vending machines, and other household appliances.

[0161] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs and the like that do not deviate from the gist of the present invention are also included in the scope of the claims. [Industrial Applicability]

[0162] The present invention is suitable for use in a communication device and a communication method. [Explanation of symbols]

[0163] 1-1, 1-2, 1-3, 1-4 Access point device 2-1, 2-12, 2-13, 2-123, 2-2, 2-21, 2-23, 2-213, 2-3, 2-31, 2-32, 2-34, 2-312, 2-4 Station equipment 3-1, 3-2, 3-3, 3-4 Communication area (coverage) 10001-1 Upper layer section 10002-1 Autonomous distributed control unit 10002a-1 CCA Department 10002b-1 Backoff section 10002c-1 Transmission decision unit 10003-1 Transmitter 10003a-1 Physical layer frame generator 10003b-1 Radio transmitter 10004-1 Receiver 10004a-1 Radio receiver 10004b-1 Signal demodulation section 10005-1 Antenna section 9-1, 9-2, 9-3, 9-4, 9-5, 9-6 Primitive 11-1, 11-2, 11-3 Frames 12-1~12-14, 12-21~12-24, 12-31~12-34, 12-41~12-44, 12-51 Frame 13-1, 13-3, 13-4 Primitive 14-1, 14-3, 14-4, 14-6, 14-7, 14-8 Primitive 20000-1 MLD access point device 13-2, 14-2, 14-5 frames 20000-2, 20000-3, 20000-4 Sub-access point device 30000-1 MLD station equipment 30000-2, 30000-3, 30000-4 Substation Equipment

Claims

1. A station device that communicates with an access point device, Connecting to a first access point device; a receiving unit that receives frames transmitted from a plurality of access point devices including a first access point device; a transmitter for transmitting a wireless management frame, the wireless management frame includes received signal quality information generated by measuring each frame transmitted by the plurality of access point devices, transmitting the wireless management frame as a solicited frame when the first access point device requests the received signal quality information; When the received signal quality information is not requested by the first access point device, at least one of a first method and a second method is executed; The first method includes notifying the received signal quality information from an MLME of a station device to an SME by a primitive; The second method transmits the radio management frame as an unsolicited frame. A station device comprising:

2. Execution of the first method and the second method is instructed by a primitive from the SME of the station device to the MLME.

2. The station device according to claim 1,

3. The received signal quality information includes at least one of an RSSI, an SNR, an SINR, and a CQI of the plurality of access point devices.

2. The station device according to claim 1, wherein the station device is a first device.

4. The received signal quality information includes capability information of the plurality of access point devices.

2. The station device according to claim 1, wherein the station device is a first device.

5. The content of the received signal quality information included in the solicited frame; The content of the received signal quality information included in the unsolicited frame is different.

2. The station device according to claim 1, wherein the station device is a first device.

6. The received signal quality information is Contains higher layer traffic requirement information; 2. The station device according to claim 1, wherein the station device is a first device.

7. An access point device for communicating with a station device, Connect with a first station device; a transmitter for transmitting frames; A receiving unit for receiving a frame, receiving an unsolicited frame including received signal quality information transmitted by the first station device; The received signal quality information is generated by the first station device by measuring frames transmitted from a plurality of access point devices including the access point device to which the first station device is connected.

1. An access point device comprising:

8. A communication method for use in a communication system including a station device, a first access point device communicating with the station device, and one or more access point devices other than the first access point device, comprising: the station device connects to a first access point device; the station device receives frames transmitted by a plurality of access point devices including a first access point device; The station device transmits a wireless management frame; the wireless management frame includes received signal quality information generated by measuring each frame transmitted by the plurality of access point devices, the station device transmits the wireless management frame as a solicited frame when the first access point device requests the received signal quality information; the station device performs at least one of a first method and a second method when the received signal quality information is not requested by the first access point device; The first method includes notifying the received signal quality information from the MLME to the SME using a primitive; The second method transmits the radio management frame as an unsolicited frame. A communication method comprising:

Images