Access point device, control method, and program

Abstract

This access point device transmits, to at least one other access point device that performs coordinated communication, a request frame for requesting a transmission buffer state, and receives, from the other access point device, a response frame including the transmission buffer state.

Description

Access point device, control method, and program

[0001] The present disclosure relates to access point devices for communicating information.

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is known as a communication standard for wireless local area networks (LANs). The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax / be (Patent Document 1). The IEEE 802.11be standard and its successor standards are designed to improve communication efficiency and throughput by cooperatively operating multiple access point devices (hereinafter simply referred to as APs). A communication technique in which multiple APs operate in cooperation is called multi-AP communication, and APs are classified into one Coordinator AP that manages all APs, and Coordinated APs that operate under the management of the Coordinator.

[0003] JP 2018-050133 A

[0004] Incidentally, as an example of multi-AP communication, a technology for improving efficiency called Coordinated TDMA (Time Division Multiple Access) is being considered, in which a portion of the TXOP (Transmission Opportunity) secured by one AP is shared and allocated to another AP, and multiple APs communicate cooperatively in a time-division manner.

[0005] However, current wireless LAN standards do not define a mechanism for acquiring information for determining the TXOP to be allocated to each AP when multiple APs perform cooperative communication.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a mechanism for acquiring information for determining a TXOP to be assigned to each AP when multiple APs perform cooperative communication.

[0007] An access point device according to one aspect of the present invention is an access point device that cooperates with one or more other access point devices to perform wireless communication in accordance with the IEEE 802.11 standard, and is characterized by having a transmitting means for transmitting a request frame to the other access point devices requesting the status of a transmission buffer, and a receiving means for receiving a response frame including the status of the transmission buffer from the other access point devices.

[0008] According to one aspect of the present invention, it is possible to provide a mechanism for acquiring information for determining a TXOP to be allocated to each AP when a plurality of APs perform cooperative communication.

[0009] 1 is a diagram illustrating an example of the configuration of a communication system. FIG. 2 is a diagram illustrating the hardware configuration of an access point device. FIG. 3 is a diagram illustrating the software configuration of an access point device. FIG. 4 is a sequence diagram illustrating processing when communication between AP101 and AP102 is DL (Down Link). FIG. 5 is a sequence diagram illustrating processing when communication between AP101 and AP102 is UL (Up Link). FIG. 6 is a sequence diagram illustrating processing when communication between AP101 and AP102 is both DL and UL. FIG. 7 is a diagram illustrating an example of a trigger frame of the present invention. FIG. 8 is a diagram illustrating a first example of a frame responding to a trigger frame of the present invention. FIG. 9 is a diagram illustrating a second example of a frame responding to a trigger frame of the present invention. FIG. 10 is a diagram illustrating a third example of a frame responding to a trigger frame of the present invention. FIG. 11 is an example of control executed by AP100. FIG. 12 is an example of control executed by AP101 to AP102. FIG. 13 is a diagram illustrating a fourth example of a frame responding to a trigger frame of the present invention.

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0011] <Configuration of communication system> Fig. 1 shows an example of the configuration of a wireless communication system according to this embodiment. This wireless communication system includes three access point devices (hereinafter simply referred to as APs, AP STAs, or access points) and four station devices (hereinafter simply referred to as STAs, Non-AP STAs, or stations). Hereinafter, APs 100-102 and STAs 120-123 will be collectively referred to as communication devices.

[0012] The APs 100 to 102 are configured to be able to communicate wireless frames that comply with the successor standard to the IEEE 802.11be standard, which targets a maximum transmission speed of 46.08 Gbps and is intended to achieve a maximum transmission speed of 90 Gbps to 100 Gbps or more. The STAs 120 to 122 are also configured to be able to communicate wireless frames that comply with the successor standard.

[0013] IEEE stands for Institute of Electrical and Electronics Engineers. This successor standard to 802.11be features support for highly reliable communication and low latency communication, as well as AP cooperation as its main features. Based on the above, in this embodiment, the successor standard to IEEE 802.11be, which targets a maximum transmission speed of 90 Gbps to 100 Gbps or more, is also referred to as UHR (Ultra High Reliability) or IEEE 802.11bn. The wireless frame communicated under this successor standard is also referred to as UHR PPDU. PPDU stands for PLCP Protocol Data Unit, and PLCP stands for Physical Layer Convergence Protocol.

[0014] The names IEEE 802.11bn and UHR standards are given for convenience in consideration of the goals to be achieved by the successor standards and the key features of the standards, and may be different names once the standards are fully formulated. However, please note that this specification and the appended claims are essentially applicable to all successor standards to the 802.11be standard that can support the function of Coordinated TDMA communication, in which multiple APs communicate cooperatively in a time-division manner.

[0015] 1 shows a wireless communication network including three APs and four STAs as an example, but the number of APs may be more or less than that shown. Furthermore, while APs 100-102 and STAs 120-123 are described as supporting UHR PPDU communication (transmission and reception), they may also be configured to support legacy PPDU communication, which is a standard that predates the UHR standard. Specifically, APs 100-102 and STAs 120-123 may be configured to support PPDU transmission and reception according to IEEE 802.11a / b / g / n / ac / ax / be standards, etc.

[0016] APs 100 to 102 are APs that perform cooperative operations, and AP 100 is an AP that performs overall control for the cooperation. In this embodiment, an AP such as AP 100 that performs overall control is also called a Coordinator AP. Furthermore, APs 101 to 102 are APs that function as controlled devices controlled by the Coordinator AP. In this embodiment, APs such as APs 101 to 102 that are controlled by the Coordinator AP are also called Coordinated APs. The roles of the Coordinator AP and the Coordinated AP may change dynamically. AP 100 provides network 110, AP 101 provides network 111, and AP 102 provides network 112. STAs 120 to 123 are STAs that participate in networks provided by access points.

[0017] In FIG. 1 , STAs 120 to 121 participate in a network 111 provided by AP 101, and STAs 122 to 123 participate in a network 112 provided by AP 102. APs 100 to 102 can perform multi-user (MU) communication, which uses OFDMA technology to simultaneously communicate with multiple STAs. In MU communication using OFDMA technology, a single channel is divided into multiple sub-channels called resource units (RUs). Each RU is then treated as a resource for communication with a different STA (which may be a group of STAs consisting of multiple STAs), allowing the AP and multiple STAs to communicate simultaneously on a single channel. In this case, the AP transmits a multi-user (MU) PPDU, in which data is modulated using OFDMA, to one or more STAs. If all devices are compatible with the UHR standard, a UHR MU PPDU, which is an MU PPDU compliant with the UHR standard, is transmitted to one or more STAs.

[0018] The APs 100-102 and the STAs 120-123 may also be configured to support wireless communication based on other communication standards, such as Bluetooth (registered trademark), NFC, or Bluetooth (registered trademark) Low Energy (LE). NFC stands for Near Field Communication. The APs 100-102 may also be configured to support wired communication using an Ethernet (registered trademark) cable or wired communication using optical fiber. Specific examples of the APs 100-102 and the STAs 120-123 include, but are not limited to, wireless LAN routers and personal computers (PCs). The APs 100-102 and the STAs 120-123 may also be information processing devices, such as wireless chips, that support the transmission and reception of UHR PPDUs. Specific examples of the STAs 120 to 123 include cameras, tablets, smartphones, PCs, mobile phones, video cameras, wearable devices such as smart glasses, etc., but are not limited to these.

[0019] In this embodiment, when the APs 100 to 102 provide a network, each network has a different BSSID. BSSID is an abbreviation for Basic Service Set Identifier, and is an identifier for identifying an access point.

[0020] Furthermore, each communication device such as APs 100 to 102 and STAs 120 to 123 can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 480 MHz, and 640 MHz.

[0021] Next, a cooperative operation in which multiple APs consisting of APs 100 to 102 operate in cooperation will be described. APs 100 to 102 can perform cooperative operation. Specifically, AP 100 can share and allocate a portion of its reserved TXOP (Transmission Opportunity) to another AP, thereby performing a coordinated TDMA communication function in which multiple APs, including AP 101, communicate at different times. Each AP can perform DL (Down Link) communication and UL (Up Link) communication with its connected STA using its assigned TXOP. In this embodiment, AP 100 is the Coordinator AP that shares and allocates the TXOP. However, another AP that first reserved the TXOP may also be designated as the Coordinator AP, and the roles of the Coordinator AP and the Coordinated AP may change dynamically.

[0022] Hereinafter, a mechanism for performing the Coordinated TDMA communication function will be specifically described. In order to effectively explain the Coordinated TDMA function, in the wireless communication system of this embodiment, the APs 100 to 102 will be described as providing a network in which STAs can participate using the same operating frequency band and the same bandwidth.

[0023] 2 shows an example of the hardware configuration of an AP. The AP has, as an example of its hardware configuration, a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and antennas 207 to 209.

[0024] The storage unit 201 is configured with ROM and / or RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. RAM stands for Random Access Memory, and ROM stands for Read Only Memory. Note that the storage unit 201 may be a storage medium such as a non-volatile storage device, such as a hard disk or SSD (Solid State Drive), in addition to memories such as ROM and RAM.

[0025] The control unit 202 is configured by, for example, a processor such as a CPU or MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc. Here, CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit 202 executes programs stored in the storage unit 201 and controls the entire device by operating hardware circuits such as the ASIC. Note that the control unit 202 may also control the entire device in cooperation with the programs stored in the storage unit 201 and an OS (Operating System).

[0026] The control unit 202 also controls the functional unit 203 to perform predetermined processes such as capturing images, printing, and projection. The functional unit 203 is hardware that enables the device to perform predetermined processes. For example, if the communication device is a camera such as a digital still camera or a smartphone equipped with a camera, the functional unit 203 is an imaging unit that captures images of the surroundings via a camera unit (not shown) included in the communication device. For example, if the communication device is a printer, the functional unit 203 is a printing unit that performs printing on a sheet such as paper based on print data obtained from the outside via wireless communication. For example, if the communication device is a projector or smart glasses, the functional unit 203 is a projection unit that performs projection of image data or video data obtained from the outside via wireless communication. In the case of smart glasses, the projection surface is the end user's retina, for example. The data processed by the functional unit 203 may be data stored in the storage unit 201 or data communicated with another AP or STA via the communication unit 206 (described later). Furthermore, communication devices such as AP 101 can also provide network storage functions such as NAS (Network Attached Storage). This function is provided to other communication devices as a web service such as a network storage service. For example, a communication device such as an STA connects to a network storage service provided by APs 101-103 using a protocol such as SMB, FTP, or WebDAV. The communication device such as an STA then uploads files to the storage service and downloads files from the storage. This upload and download data communication is also realized by communicating UHR PPDU between devices.

[0027] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes, for example, at least one of display on a screen, audio output by a speaker, vibration output, etc. Note that both the input unit 204 and the output unit 205 may be implemented by a single module, such as a touch panel.

[0028] The communication unit 206 controls wireless communications compliant with the IEEE 802.11 standard series and IP communications. In this embodiment, the communication unit 206 cooperates with the antennas 207 to 209 to transmit and receive UHR PPDUs, which are wireless frames conforming to the UHR standard, as well as PPDUs conforming to earlier standards. The antennas 207 to 209 are antennas capable of transmitting and receiving signals in at least one of the following frequency bands: sub-GHz, 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, and 60 GHz. While the present embodiment describes the presence of three antennas, a single antenna may be used, or a different antenna may be used for each frequency band. Furthermore, if multiple antennas are used, a communication unit 206 may be provided corresponding to each antenna.

[0029] If the communication device is compatible with the NFC standard, Bluetooth (registered trademark) standard, or the like, the communication unit 206 may be configured to control wireless communication in accordance with these communication standards.

[0030] Next, the functional configuration of the APs 100 to 102 will be explained using Fig. 3. Note that Fig. 3 shows only the functional configuration necessary for explaining the TXOP allocation function. The AP has a frame processing unit 301, a TXOP allocation processing unit 302, and a frame transmission / reception unit 303.

[0031] Each function will be described below. The frame processing unit 301 works in cooperation with the antennas 207 to 209 to interpret various wireless frames received from the outside and notify upper layer functions (not shown), and performs wireless communication control processing based on the information obtained through the interpretation. If the frame processing unit 301 is the data transmission source communication device, it generates a data frame. In the case of the AP 100, the frame processing unit 301 is a block that generates a Multi-AP BSRP (Buffer Status Report Poll) Trigger frame to be transmitted to the APs 101 to 102 to acquire information for determining the TXOP, acquires information for determining the TXOP from the AP BSR (Buffer Status Report) frames received from the APs 101 to 102, and generates a Trigger frame for allocating the determined TXOP to the APs 101 to 102. The frame processing unit 301 is a block that processes the Multi-AP BSRP Trigger frame received from AP100 in the case of AP101 to AP102, generates an AP BSR frame containing information for determining the TXOP, and processes the Trigger frame for allocating the TXOP received from AP100.

[0032] The TXOP allocation processing unit 302 determines the TXOP to be allocated to the APs 101 to 102 based on the information for determining the TXOP included in the AP BSR frame acquired from the APs 101 to 102 in the case of the AP 100. Furthermore, the TXOP allocation processing unit 302 determines the TXOP allocated to itself in accordance with the contents of the Trigger frame for allocating the TXOP in the case of the APs 101 to 102, and communicates with the STA connected to itself.

[0033] The frame transmitting / receiving unit 303 cooperates with the antennas 207 to 209 to transmit wireless frames such as UHR PPDUs generated by the frame processing unit 301 to external APs and STAs. The specific formats of the Multi-AP BSRP Trigger frame and AP BSR frame will be described later.

[0034] Next, the procedure for acquiring information for determining the TXOP to be assigned to the Coordinated AP will be described with reference to the sequence diagrams of Figures 4 and 5. Figure 4 is a sequence diagram showing an example of wireless frame exchange when the Coordinated AP wishes to perform DL communication with a STA connected thereto. DL communication refers to data communication from the AP to the STA.

[0035] AP 100, which is the Coordinator AP, transmits a Multi-AP BSRP Trigger frame 401, which is a request frame requesting information for determining the TXOP to be allocated to the Coordinating APs with which it is coordinating. APs 101 and 102 that receive this Multi-AP BSRP Trigger frame 401 transmit AP BSR frames 402 and 403, which include the transmit buffer status necessary for DL ​​communication with each STA connected to them, as response frames to AP 100. In this embodiment, by including in the Multi-AP BSRP Trigger frame 401 RU allocation information when each AP transmits an AP BSR frame, AP 101 and AP 102 simultaneously transmit AP BSR frames 402 and 403 using RUs assigned by OFDMA communication. The transmission of the AP BSR frame is not limited to OFDMA communication, and for example, the AP BSR may be transmitted in a time-division manner by TDMA communication in accordance with the AP transmission order specified in the Multi-AP BSRP Trigger frame.

[0036] Upon receiving the AP BSR frames 402 and 403, the AP 100 checks the state of the transmission buffer required for DL ​​communication for each AP, and can determine the TXOP to be allocated.

[0037] After determining the TXOP to be allocated, AP 100 notifies each of APs 101 to 102 of the allocation information for that TXOP. While this notification method is assumed to be, for example, the transmission of MU-RTS TXS Trigger frames 404 and 406, as long as it can notify the information of the TXOP to be allocated, it is not limited to this. MU-RTS TXS Trigger frames are frames used in IEEE 802.11be and later standards. Upon receiving this notification, APs 101 to 102 execute DL communication processing with the STAs connected to them during the periods of the allocated TXOPs 405 and 406, respectively. In this embodiment, an MU-RTS TXS Trigger frame is transmitted to each of AP101 to AP102 to notify them of the TXOP to be allocated, but a single frame may be used to indicate the TXOP information to be allocated to each of AP101 to AP102 and the order in which the TXOPs are allocated.

[0038] 5 is a sequence diagram showing an example of wireless frame exchange when a Coordinated AP wishes to perform UL communication with a STA connected thereto. UL communication refers to data communication from the STA to the AP.

[0039] AP 100, the Coordinator AP, transmits a Multi-AP BSRP Trigger frame 501 requesting information for determining the TXOP to be allocated to the Coordinating APs with which it is coordinating. APs 101 to 102 that receive this Multi-AP BSRP Trigger frame 501 check the transmit buffer status of each STA in order to perform UL communication with the connected STAs 120 to 123. The Multi-AP BSRP Trigger frame 501 can include information on the order in which each AP transmits its BSRP Trigger frame, timing information for each AP to transmit its AP BSR frame, and RU allocation information for each AP when transmitting its AP BSR frame. In this embodiment, the order in which BSRP Trigger frames are transmitted is AP 101, followed by AP 102. To achieve this, AP 101 first transmits a BSRP Trigger frame 502 and receives notifications from the STAs via BSR frames 503-504, thereby obtaining the buffer status of each STA. BSRP Trigger frames and BSR frames are frames used in IEEE 802.11ax and later standards. Next, AP 102 transmits a BSRP Trigger frame 505 and receives notifications from the STAs via BSR frames 506-507, thereby obtaining the transmit buffer status of each STA. Next, AP 101 and AP 102 simultaneously transmit AP BSR frames 508-509 using the RUs assigned by OFDMA communication, according to the timing information specified in Multi-AP BSRP Trigger frame 501. The transmission of the AP BSR frame is not limited to OFDMA communication, and for example, the AP BSR may be transmitted in a time-division manner by TDMA communication in accordance with the AP transmission order specified in the Multi-AP BSRP Trigger frame.Furthermore, if an AP that has received a Multi-AP BSRP Trigger frame already knows the transmission buffer status of the STA connected to itself, for example by transmitting a BSRP Trigger frame before receiving the Multi-AP BSRP Trigger frame, the AP may directly transmit an AP BSR frame without transmitting a BSRP Trigger frame again.

[0040] Upon receiving the AP BSR frames 508 to 509, the AP 100 checks the state of the transmission buffer required for UL communication of each AP and can determine the TXOP to be allocated.

[0041] AP 100, which has determined the TXOP to be allocated, notifies each of APs 101 to 102 of the allocation information of the TXOP using MU-RTS TXS Trigger frames 510 and 512, as in the case of Fig. 4. Upon receiving the notification, APs 101 to 102 execute UL communication processing with the STAs connected thereto during the periods of the allocated TXOPs 511 and 513, respectively.

[0042] As described above with reference to FIGS. 4 and 5, the AP 100 that has transmitted the Multi-AP BSRP Trigger frame can obtain information for determining the TXOP to be allocated to the Coordinated AP.

[0043] While the explanation has been given separately for the cases of DL communication and UL communication using Fig. 4 and Fig. 5, Fig. 6 is a sequence diagram showing an example of wireless frame exchange when a Coordinated AP wants to perform both DL communication and UL communication. It is assumed that AP 101 wants to perform only DL communication, and AP 102 wants to perform both DL communication and UL communication.

[0044] The AP 100, which is the Coordinator AP, transmits a Multi-AP BSRP Trigger frame 601 to the Coordinated APs with which it is coordinating, requesting information for determining the TXOP to be allocated.

[0045] Upon receiving the Multi-AP BSRP Trigger frame 601, the AP 101 responds to the AP 100 with an AP BSR frame 605 including the transmission buffer status necessary for performing DL communication with each STA connected to the AP 100 at a predetermined timing as described in Fig. 5. Furthermore, upon receiving the Multi-AP BSRP Trigger frame 601, if the AP 102 is to perform not only DL communication but also UL communication, the AP 102 transmits a BSRP Trigger frame 602 for checking the transmission buffer status of each STA as described in Fig. 5. Upon receiving BSR frames 603-604 from the STAs 122-123, the AP 102 notifies the AP 100 of the information including the transmission buffer status of each STA and the transmission buffer status necessary for the AP 100 to perform DL communication. AP 100, which has determined the TXOP to be allocated, notifies each of APs 101 to 102 of the allocation information of that TXOP using MU-RTS TXS Trigger frames 607 and 609, as in the case of Fig. 4. Upon receiving the notification, AP 101 performs DL communication processing with the STA connected to itself during the period of the allocated TXOP 608, and AP 102 performs DL and UL communication processing with the STA connected to itself during the period of the allocated TXOP 610.

[0046] As described above with reference to FIG. 6, even when the Coordinated AP wishes to perform both DL communication and UL communication, the AP 100 can obtain information for determining the TXOP to be allocated.

[0047] (Frame Structure) Next, the structure of a frame communicated in this embodiment will be described with reference to FIGS.

[0048] 7 is a diagram showing an example of a Multi-AP BSRP Trigger frame format transmitted by AP 100. The Frame Control field 701 is a field in which a value indicating that the frame is a Trigger frame used in standards after IEEE 802.11ax is entered. The Common Info field 702 indicates information common to multiple APs that are the destinations of this Trigger frame. The Trigger Type field 703 contains information for identifying the Trigger frame, as shown in Table 1. The Trigger Dependent Common Info field 704 contains information that depends on each Trigger frame.

[0049]

[0050] 7 is called, for example, a Multi-AP BSRP Trigger frame. In this case, the Trigger Type field 703 is set to "8." Alternatively, for example, a new Trigger Type for the Multi-AP BSRP Trigger frame may be defined and used from the values ​​marked "Reserved" in Table 1.

[0051] In addition, a new Trigger Type may be defined and used that distinguishes whether the transmission buffer status information to be responded is for DL ​​communication or UL communication. A Coordinated AP that receives a Trigger frame for DL ​​communication responds with the transmission buffer status information required for DL ​​communication. This Trigger frame for DL ​​communication is called, for example, a Multi-AP-BSRP DL Trigger frame, and the Trigger Type is defined as "9". On the other hand, a Coordinated AP that receives a Trigger frame for UL communication responds with the transmission buffer status information required for UL communication. This Trigger frame for UL communication is called, for example, a Multi-AP-BSRP UL Trigger frame, and the Trigger Type is defined as "10". A new Trigger Type indicating both UL and DL communication may be defined and used. This may be defined from the reserved values, or the Multi-AP BSRP Trigger frame defined as "8" may be used.

[0052] Furthermore, the identification information for distinguishing between DL communication and UL communication may not use the Trigger Type, but may use other information. For example, a field for setting information for distinguishing between them may be provided in the Trigger Dependent Common Info field 704. For example, a Direction field 705 may be provided, and a value of "0" in this field indicates DL communication, a value of "1" indicates UL communication, and a value of "2" indicates both DL and UL communication. A Coordinated AP that receives a Trigger frame with a Trigger Type of "8" can check this subfield to distinguish between DL communication and UL communication.

[0053] The Trigger Dependent Common Info field 704 may include a BSRP required field 706 indicating whether the AP that received the Multi-AP BSRP Trigger frame should transmit a BSRP Trigger frame to the STA connected to it. For example, if the BSRP required field 706 is set to "0," transmission of the BSRP Trigger frame is not required, and if it is set to "1," transmission of the BSRP Trigger frame is required. If the BSRP required field is set to "0" or if the AP already knows the transmission buffer status of the STA connected to it, it may transmit an AP BSR frame without transmitting a new BSRP Trigger frame. Furthermore, the BSRP order field 707 is information indicating the transmission order when each AP is made to transmit a BSRP Trigger frame. For example, a list of BSSIDs indicating the transmission order of APs may be included, or a list of BSS colors may be included. Also, the Feedback Timing field 708 includes information indicating the timing at which each AP transmits an AP BSR frame.

[0054] For example, the time until the AP BSR is transmitted based on the reception time of the Multi-AP BSRP Trigger frame may be indicated in microseconds or milliseconds. In addition to requesting the AP for the transmission buffer status, a TX Parameter Required field 712 may be included, indicating that the AP's transmission parameters for DL ​​communication or the STA's transmission parameters for UL communication are requested. For example, in the case of DL communication, the transmission parameters include information on the MCS (Modulation and Coding Scheme) and transmission power applied to the PPDU transmitted by the AP when the AP performs DL communication with the STA connected thereto. For example, in the case of UL communication, the transmission parameters include information on the MCS and transmission power applied to the PPDU transmitted by the STA when the AP performs UL communication with the STA connected thereto.

[0055] For example, if the TX Parameter Required field 712 is set to "0," it is not necessary to include transmission parameters in the AP BSR frame, and if it is set to "1," it is necessary to include transmission parameters in the AP BSR frame. The Coordinator AP can more accurately determine the TXOP to allocate to the Coordinator AP by acquiring the transmission parameters for DL ​​communication or UL communication in addition to the transmission buffer capacity for DL ​​communication or UL communication of the Coordinator AP. In the example of FIG. 7 , the TX Parameter Required field 712 is a field indicating that the AP's transmission parameters for DL ​​communication and the STA's transmission parameters for UL communication are required, but the field may be separated for DL ​​communication and UL communication.

[0056] The User Info field 709 stores information specific to each AP. The AP ID field 710 stores information for identifying the AP, such as the BSSID and BSS color. The RU Allocation field 711 stores information indicating the OFDMA RU allocated to the AP specified in the AP ID field 710. Each AP can simultaneously transmit AP BSR frames via OFDMA communication using the allocated RU.

[0057] Furthermore, the Frame Control field 701 includes a Type subfield and a Subtype subfield that indicate the frame type. In this embodiment, a frame in which "01" is set in the Type subfield and "0010" is set in the Subtype subfield is defined as a Multi-AP-BSRP Trigger frame. Note that the Type subfield and the Subtype subfield may have different values ​​as long as the Multi-AP-BSRP Trigger frame can be identified. For example, as shown in Table 2, a frame in which "11" indicating Extension is set in the Type subfield and "0011" or the like is set in the Subtype subfield can be defined as a Multi-AP-BSRP Trigger frame.

[0058]

[0059] The Multi-AP BSRP Trigger frame is an example of the name of a frame for requesting information for determining the TXOP to be allocated to the access point, and may have another name.

[0060] 8 shows an example of the configuration of an AP BSR frame used by AP101 to AP102 when notifying AP100. Information indicating the transmission buffer status for DL ​​communication is included in a DL Buffer Status field 801. The DL Buffer Status field 801 includes the queue sizes of TID (Traffic Identifier) ​​#0 to #15, and for example, 803 indicates the total queue size obtained by aggregating the transmission buffer status of data for TID #0 addressed to all STAs. In addition, information indicating the transmission buffer status for UL communication is included in a UL Buffer Status field 802. The UL Buffer Status field 802 includes the queue sizes of TIDs 0 to 15. For example, 804 indicates the total queue size obtained by aggregating the transmission buffer status of all STAs having data for TID 0. The queue size may indicate the number of octets indicating the data size, or may indicate the number of data blocks of a predetermined number of octets. Alternatively, the queue size of TIDs 0 to 15 may be indicated for each STA.

[0061] 9 shows another example of the configuration of an AP BSR frame. In the example of FIG. 8, one DL Buffer Status field contained all of the queue sizes for TIDs #0 to #15, but in FIG. 9, one DL Buffer Status field contains a TID field 903 that identifies the TID and a Queue size field 904 that indicates the transmission buffer status. 904 indicates the total queue size obtained by aggregating the transmission buffer status of data for all STAs with the TID specified in TID field 903. Similarly, the UL Buffer Status field 902 also contains a TID field 905 that identifies the TID and a Queue size field 906 that indicates the UL transmission buffer status for the TID specified in TID field 905. If data for multiple TIDs is buffered, the AP BSR frame may include multiple DL Buffer Status fields or multiple UL Buffer Status fields.

[0062] Fig. 10 shows another example of the configuration of an AP BSR frame. In Fig. 8 and Fig. 9, the fields indicating the transmission buffer status are shown separately for DL ​​communication and UL communication, but in Fig. 10, a single field is used that aggregates the transmission buffer status for DL ​​communication and UL communication. An Aggregated Buffer Status field 1001 contains the total queue size obtained by aggregating the transmission buffer status for DL ​​communication and the transmission buffer status for UL communication.

[0063] Although the queue size for each TID is shown in FIGS. 8 and 9, the queue size may be the total of the queue sizes for all TIDs.

[0064] 13 shows another example in which the Queue size for each STA is indicated in the DL Buffer Status field and the UL Buffer Status field in the AP BSR frame. Information indicating the transmission buffer status for DL ​​communication is included in the DL Buffer Status field 1300. The DL Buffer Status field 1300 includes a STAID (Station Identifier) ​​field 1301, which includes information identifying the STA connected to the Coordinated AP. The STAID field 1301 includes, for example, the MAC address of the STA and AID (Association Identifier) ​​information. The Queue Size field 1302 includes information indicating the size of the transmission buffer for data addressed to the STA identified in the STAID field 1301. Furthermore, the TX Parameter field 1303 stores transmission parameters to be applied when the Coordinated AP transmits data addressed to the STA identified by the STA ID field 1301. The transmission parameters include, for example, an MCS field 1304 and a TX Power field 1305. The MCS field 1304 includes information on a modulation method, such as QPSK (Quadrature Phase Shift Keying) or 16QAM (Quadrature Amplitude Modulation), and information on a coding rate. The TX Power field 1305 indicates the value of transmission power when the MCS specified in the MCS field 1304 is applied to the PPDU to be transmitted. When the Coordinating AP receives a Multi-AP BSRP Trigger frame with the TX Parameter Required field set to 1 from the Coordinator AP, the Coordinating AP may include a TX Parameter field 1303 in the AP BSR frame.The Coordinator AP that has acquired this information can calculate the communication time required to transmit data of the size specified in the Queue Size field 1302 using the transmission parameters specified in the TX Parameter field 1303, and can more accurately estimate the TXOP to be assigned to the Coordinator AP. In the example of Fig. 13, the AP BSR frame includes DL Buffer Status information for one STA, but it may also include information for multiple STAs.

[0065] Furthermore, information indicating the status of the transmission buffer for UL communication is included in a UL Buffer Status field 1310. The UL Buffer Status field 1310 includes a STAID (Station Identifier) ​​field 1311, which includes information for identifying a STA connected to the Coordinated AP. The Queue Size field 1312 includes information indicating the size of the transmission buffer for data addressed to the Coordinated AP by the STA identified in the STAID field 1301. Furthermore, the TX Parameter field 1313 stores transmission parameters that are applied when a STA connected to the Coordinated AP identified in the STAID field 1311 transmits data addressed to the Coordinated AP.

[0066] The transmission parameters include, for example, an MCS field 1314 and a TX Power field 1315. The Coordinator AP that acquires this information can calculate the communication time required to transmit data of the size specified in the Queue Size field 1312 using the transmission parameters specified in the TX Parameter field 1313, and can more accurately estimate the TXOP to be assigned to the Coordinator AP. In the example of Fig. 13, an AP BSR frame includes UL Buffer Status information for one STA, but the AP BSR frame may also include information for multiple STAs.

[0067] The AP BSR frame in this embodiment is an example of the name of a frame for notifying information for determining a TXOP to be assigned to an access point, and may have a different name.

[0068] (Processing Flow) The control of the TXOP determination process executed by the Coordinator AP of the present invention will be described with reference to the flowchart in Fig. 11. The AP 100 starts this process when it determines to allocate part of its reserved TXOP to the Coordinated AP.

[0069] First, the AP 100 generates a Multi-AP BSRP Trigger frame requesting information for determining the TXOP to be allocated (S1101). For example, when using the Multi-AP BSRP Trigger frame of FIG. 7, "8" indicating Multi-AP BSRP Trigger is set in the Trigger Type field 703. In addition, various fields included in the Trigger Dependent Common Info field 704 and a User Info field containing information specific to each AP are set. Next, the AP 100 transmits the Multi-AP BSRP Trigger frame (S1102). This frame is broadcast to the surrounding area including APs 101 and 102.

[0070] The AP 100 then receives the AP BSR frames transmitted by the APs 101 and 102 in response to the Multi-AP BSRP Trigger frame (S1103) and acquires the information contained in the AP BSR frames (S1104). The AP 100 then determines the TXOP to be allocated to each Coordinating AP based on the transmission buffer status information contained in the AP BSR frames (S1105). The TXOP may be determined, for example, by determining the ratio of the TXOP to be allocated to each AP according to the ratio of the buffer capacity indicated in each AP BSR frame. Alternatively, the AP 100 may calculate the communication time required to transmit the buffered amount of data indicated in each AP BSR frame and determine the TXOP to be allocated, or may determine the TXOP to be allocated to each AP based on the buffer capacity of a high-priority TID. Transmission parameter information acquired from the Coordinating AP may be used to calculate the communication time required to transmit the data. For example, if the transmission parameter information includes an MCS, it is possible to determine the data rate of the physical layer, and the communication time can be determined based on the data rate and the buffer amount. Furthermore, if the transmission parameters include transmission power information, the communication time can be calculated when the transmission power of the Coordinated AP or a STA connected to the Coordinated AP is changed. For example, when the transmission power is increased above the transmission power notified in the AP BSR frame, it may be possible to increase the data rate of the physical layer and shorten the communication time by applying an MCS with a higher data rate than the MCS notified in the AP BSR frame. When the transmission power is changed, the Coordinator AP may instruct the Coordinated AP or a STA connected to the Coordinated AP to change the transmission power by including information about the changed transmission power in an MU-RTS TXS Trigger frame for allocating a TXOP.

[0071] As described above, the Coordinator AP can obtain information on the transmission buffer status by transmitting a Trigger frame requesting information for determining the TXOP to be allocated to the Coordinating AP. After obtaining the information on the transmission buffer status from the Coordinating AP, the AP 100 can determine the TXOP to be allocated to the Coordinating AP.

[0072] Next, the control executed in the Coordinated AP of the present invention will be explained using the flowchart in Figure 12. AP 101 and AP 102 start this process when they determine that they have received a Multi-AP BSRP Trigger frame requesting information for determining the TXOP to be allocated by the Coordinator AP. While the following explanation focuses on AP 101, AP 102 also performs similar processing.

[0073] First, the AP 101 determines whether a TXOP is required for DL ​​communication (S1201). For example, when using the Multi-AP BSRP Trigger frame of FIG. 7, the AP 101 may determine whether DL communication is required based on the Direction field 705, or the AP 101 itself may determine whether DL communication is required regardless of the contents of the Multi-AP BSRP Trigger frame. If the AP 101 determines in S1201 that a TXOP is required for DL ​​communication, the AP 101 acquires the transmission buffer status required for DL ​​communication (S1202). Next, the AP 101 determines whether a TXOP is required for UL communication as well (S1203). If a TXOP is required only for DL ​​communication, the AP 101 transmits an AP BSR frame including information indicating the required transmission buffer status to the Coordinator AP (S1204). For example, when the AP BSRP frame shown in FIG. 8 is used, information indicating the required transmission buffer status is set in the DL Buffer Status field and transmitted.

[0074] On the other hand, if it is determined in S1201 that a TXOP is not required for DL ​​communication, or if it is determined in S1203 that a TXOP is also required for UL communication, the AP 101 transmits a BSRP Trigger frame to notify the STA connected to the AP 101 of the transmission buffer status (S1205). Note that if the AP 101 already knows the transmission buffer status of the connected STA, it may skip steps S1205 and S1206. Next, the AP 101 that transmitted the BSRP Trigger frame in S1205 receives a BSR frame including the transmission buffer status from the STA (S1206) and acquires the transmission buffer status included in the received BSR frame (S1207). Then, it transmits a response including the transmission buffer status information indicated in the AP BSR frame to the Coordinator AP (S1204). For example, when the AP BSRP frame of Figure 8 is used, information indicating the required transmission buffer status is set in the UL Buffer Status field and transmitted. Note that when the transmission buffer status of each STA is not included in the UL Buffer Status field as in Figure 8, a transmission buffer status that aggregates the transmission buffer status included in the BSR frame of each STA for each TID is stored in this field. Also, for example, when an AP BSR frame in which the transmission buffer status for DL ​​and the transmission buffer status for UL are combined in one field as in Figure 10 is used, a transmission buffer status that aggregates the transmission buffer status included in the BSR frame of each STA and the transmission buffer status of the AP is stored in this one field.

[0075] In this way, the Coordinated AP can respond to a Multi-AP BSRP Trigger frame requesting information for determining the TXOP to be allocated.

[0076] (Other Modifications) In the above-described embodiments, the Coordinator AP responds to the Trigger frame transmitted by the Coordinator AP with information about the status of its transmission buffer. However, this is not limited to this. Any information necessary for the Coordinator AP to determine the TXOP to be allocated may be used. Instead of the information about the status of the transmission buffer, the Coordinator AP may respond with, for example, information about the communication time it wishes the Coordinator AP to allocate. For example, the communication time may be specified in units such as microseconds or milliseconds, or as a multiple of a predetermined time unit.

[0077] The present invention can also be realized by a process in which a program that realizes one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., an ASIC) that realizes one or more of the functions.

[0078] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

[0079] (Summary of the embodiment) At least some of the above-described embodiments can be summarized as follows.

[0080] (Item 1) An access point device that cooperates with one or more other access point devices and performs wireless communication compliant with the IEEE 802.11 standard, comprising: a transmitting means that transmits a request frame to the other access point devices to request the status of a transmission buffer; and a receiving means that receives a response frame including the status of the transmission buffer from the other access point devices.

[0081] (Item 2) The access point device according to item 1, wherein the request frame includes information indicating a request for a status of a transmission buffer of the other access point device in DL (Down Link) communication of the other access point device.

[0082] (Item 3) The access point device according to item 1 or 2, wherein the request frame includes information indicating a request for the status of a transmission buffer of one or more stations connected to the other access point device in UL (Up Link) communication of the other access point device.

[0083] (Item 4) The access point device according to any one of items 1 to 3, wherein the request frame includes information requesting acquisition of transmission parameters of the other access point device in the DL communication.

[0084] (Item 5) The access point device according to any one of items 1 to 4, wherein the request frame includes information requesting acquisition of transmission parameters of one or more stations connected to the other access point device in the UL communication.

[0085] (Item 6) The access point device according to any one of items 1 to 5, wherein the request frame includes information regarding an order in which to obtain the status of transmission buffers of one or more stations connected to the other access point device in the UL communication.

[0086] (Item 7) The access point device according to any one of items 1 to 6, wherein the request frame includes information regarding a timing for transmitting the response frame.

[0087] (Item 8) The access point device according to any one of items 1 to 7, wherein the response frame includes a state of a transmission buffer of the other access point device in the DL communication.

[0088] (Item 9) The access point device according to any one of items 1 to 8, wherein the response frame includes a status of a transmission buffer of one or more station devices connected to the other access point device in the UL communication.

[0089] (Item 10) The access point device according to any one of items 1 to 9, wherein the response frame includes a transmission parameter of the other access point device in the DL communication.

[0090] (Item 11) The access point device according to any one of items 1 to 10, wherein the response frame includes transmission parameters of one or more stations connected to the other access point device in the UL communication.

[0091] (Item 12) The access point device according to any one of items 1 to 11, wherein the response frame includes information summarizing the status of transmission buffers of one or more station devices connected to the other access point device.

[0092] (Item 13) The access point device described in any one of items 1 to 12, characterized in that the response frame includes information that aggregates the status of the transmission buffer of the other access point device and the status of the transmission buffer of one or more station devices connected to the other access point device.

[0093] (Item 14) An access point device that cooperates with one or more other access point devices and performs wireless communication in accordance with the IEEE 802.11 standard, comprising: a transmitting means that transmits a request frame requesting communication time to the other access point devices; and a receiving means that receives a response frame including the communication time from the other access point devices.

[0094] (Item 15) The access point device according to item 14, wherein the request frame includes information indicating a request for communication time of the other access point device in DL (Down Link) communication of the other access point device.

[0095] (Item 16) The access point device according to item 14 or 15, wherein the request frame includes information indicating a request for communication time for one or more stations connected to the other access point device in UL (Up Link) communication of the other access point device.

[0096] (Item 17) The access point device according to any one of items 14 to 16, wherein the request frame includes information regarding an order in which communication time of one or more stations connected to the other access point device is to be acquired.

[0097] (Item 18) The access point device according to any one of items 14 to 17, wherein the response frame includes a communication time of the other access point device in the DL communication.

[0098] (Item 19) The access point device according to any one of items 14 to 18, wherein the response frame includes communication times of one or more station devices connected to the other access point device in the UL communication.

[0099] (Item 20) The access point device according to any one of items 14 to 19, wherein the response frame includes information summarizing communication times of one or more station devices connected to the other access point device.

[0100] (Item 21) The access point device described in any one of items 14 to 20, characterized in that the response frame includes information that aggregates the communication time of the other access point device and the communication time of one or more station devices connected to the other access point device.

[0101] (Item 22) A control method for an access point device that cooperates with one or more other access point devices and performs wireless communication compliant with the IEEE 802.11 standard, the control method comprising: a transmitting step of transmitting a request frame to the other access point devices requesting the status of a transmission buffer; and a receiving step of receiving a response frame including the status of the transmission buffer from the other access point devices.

[0102] (Item 23) A control method for an access point device that cooperates with one or more other access point devices and performs wireless communication compliant with the IEEE 802.11 standard, the control method comprising: a transmitting step of transmitting a request frame requesting communication time to the other access point devices; and a receiving step of receiving a response frame including the communication time from the other access point devices.

[0103] (Item 24) A program for causing a computer to execute the control method for the access point device according to either item 22 or 23.

[0104] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

[0105] This application claims priority based on Japanese Patent Application No. 2023-141711 filed on August 31, 2023 and Japanese Patent Application No. 2024-091839 filed on June 5, 2024, the entire contents of which are incorporated herein by reference.

[0106] 100 AP 101 AP 102 AP 110 Network 111 Network 112 Network 120 STA 121 STA 122 STA 123 STA

Claims

1. An access point device that cooperates with one or more other access point devices and performs wireless communication compliant with the IEEE 802.11 standard, comprising: a transmitting means for transmitting a request frame to the other access point devices to request the status of a transmission buffer; and a receiving means for receiving a response frame including the status of the transmission buffer from the other access point devices.

2. The access point device according to claim 1, characterized in that the request frame includes information indicating a request for a status of a transmission buffer of the other access point device in DL (Down Link) communication of the other access point device.

3. The access point device according to claim 1, characterized in that the request frame includes information indicating a request for the status of a transmission buffer of one or more stations connected to the other access point device in UL (Up Link) communication of the other access point device.

4. The access point device according to claim 2, characterized in that the request frame includes information requesting acquisition of transmission parameters of the other access point device in the DL communication.

5. The access point device according to claim 3, characterized in that the request frame includes information requesting acquisition of transmission parameters of one or more stations connected to the other access point device in the UL communication.

6. The access point device according to claim 3, characterized in that the request frame includes information regarding an order for obtaining the status of a transmission buffer of one or more stations connected to the other access point device in the UL communication.

7. The access point device according to claim 1, wherein the request frame includes information regarding a timing for transmitting the response frame.

8. The access point device according to claim 1, characterized in that the response frame includes a state of a transmission buffer of the other access point device in the DL communication.

9. The access point device according to claim 1, wherein the response frame includes a status of a transmission buffer of one or more station devices connected to the other access point device in the UL communication.

10. The access point device according to claim 8, wherein the response frame includes a transmission parameter of the other access point device in the DL communication.

11. The access point device according to claim 9, wherein the response frame includes transmission parameters of one or more stations connected to the other access point device in the UL communication.

12. The access point device according to claim 1, wherein the response frame includes information summarizing the states of transmission buffers of one or more station devices connected to the other access point device.

13. The access point device according to claim 1, characterized in that the response frame includes information summarizing the status of the transmission buffer of the other access point device and the status of the transmission buffer of one or more station devices connected to the other access point device.

14. An access point device that cooperates with one or more other access point devices and performs wireless communication compliant with the IEEE 802.11 standard, comprising: a transmitting means for transmitting a request frame requesting communication time to the other access point devices; and a receiving means for receiving a response frame including the communication time from the other access point devices.

15. The access point device according to claim 14, characterized in that the request frame includes information indicating a request for communication time of the other access point device in DL (Down Link) communication of the other access point device.

16. The access point device according to claim 14, characterized in that the request frame includes information indicating a request for communication time for one or more stations connected to the other access point device in UL (Up Link) communication of the other access point device.

17. The access point device according to claim 16, wherein the request frame includes information regarding the order in which communication time is to be acquired for one or more stations connected to the other access point devices.

18. The access point device according to claim 14, characterized in that the response frame includes a communication time of the other access point device in the DL communication.

19. The access point device according to claim 14, wherein the response frame includes communication times of one or more station devices connected to the other access point device in the UL communication.

20. The access point device according to claim 14, characterized in that the response frame includes information aggregating communication times of one or more station devices connected to the other access point devices in the UL communication.

21. The access point device according to claim 14, characterized in that the response frame includes information that aggregates the communication time of the other access point device and the communication time of one or more station devices connected to the other access point device.

22. A control method for an access point device that cooperates with one or more other access point devices and performs wireless communication compliant with the IEEE 802.11 standard, comprising: a transmission step of transmitting a request frame to the other access point devices to request the status of a transmission buffer; and a reception step of receiving a response frame including the status of the transmission buffer from the other access point devices.

23. A control method for an access point device that cooperates with one or more other access point devices and performs wireless communication compliant with the IEEE 802.11 standard, comprising: a transmission step of transmitting a request frame requesting communication time to the other access point devices; and a reception step of receiving a response frame including the communication time from the other access point devices.

24. A program for causing a computer to execute the method for controlling an access point device according to claim 22 or 23.

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