Communication device, communication method, and program

Abstract

To ensure frame compatibility when information is communicated regarding a link established with another communication device on a frequency channel conforming to the IEEE 802.11 series standards.SOLUTION: A link is established between a communication device 102 and a communication device 103 on a frequency channel capable of performing wireless communication conforming to the IEEE802.11 series standards, and the communication device 102 and the communication device 103 communicate a MAC (Media Access Control) frame including information regarding a second link different from the established first link as information to be communicated after SSID (Service Set Identifier) information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the transmission and reception of information regarding communication in wireless communication. [Background technology]

[0002] The IEEE802.11 series is known as a WLAN communication standard established by the IEEE (Institute of Electrical and Electronics Engineers). WLAN is an abbreviation for Wireless Local Area Network. The IEEE802.11 series standards include the IEEE802.11a / b / g / n / ac / ax standards.

[0003] In order to further improve throughput and frequency utilization efficiency, IEEE is considering the formulation of the IEEE802.11be standard as a new standard in the IEEE802.11 series. The IEEE802.11be standard considers Multi-Link communication, in which one AP (Access Point) establishes multiple links with one STA (Station) via multiple different frequency channels to communicate.

[0004] Patent Document 1 discloses that a link is established when an AP and a STA communicate with each other. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2012-523202 Summary of the Invention [Problem to be solved by the invention]

[0006] In multi-link communication, for example, it is possible to give priority to communication using links that are relatively less congested among multiple links. To perform such control, information about other links needs to be communicated between the AP and STA. However, since multi-link communication is a new technology introduced in the IEEE802.11 series of standards, when communicating information about other links using, for example, MAC frames, compatibility needs to be taken into consideration. MAC is an abbreviation for Media Access Control.

[0007] In view of the above, an object of the present invention is to ensure frame compatibility when communicating information regarding a link established with another communication device on a frequency channel compliant with the IEEE 802.11 series standards. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the communication device of the present invention has an establishment means for establishing a link with another communication device on a frequency channel capable of performing wireless communication conforming to the IEEE802.11 series standard, and a communication means for communicating a MAC (Media Access Control) frame including information regarding a second link with the other communication device, which is different from a first link established by the establishment means, as information communicated after SSID (Service Set Identifier) ​​information. Effect of the Invention

[0009] According to the present invention, frame compatibility can be ensured by appropriately communicating information regarding a link established with another communication device on a frequency channel compliant with the IEEE 802.11 series standards. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a configuration of a network to which a communication device 102 belongs. [Diagram 2]FIG. 2 is a diagram illustrating a hardware configuration of a communication device 102. [Diagram 3] FIG. 2 is a diagram illustrating a functional configuration of a communication device 102. [Figure 4] 10 is a sequence diagram showing an example of a process executed when communication devices 102 and 103 establish a link for multi-link communication. FIG. [Diagram 5] FIG. 13 is a diagram illustrating an example of a frame format of a Multi-Link Capability Element. [Figure 6] 11 is a flowchart showing a process executed by the communication device 103 when performing multi-link communication. [Figure 7] 10 is a flowchart showing the process executed by the communication device 102 when performing multi-link communication. [Figure 8] FIG. 13 is a diagram showing information contained in a Beacon. [Figure 9] FIG. 13 is a diagram showing information contained in a Probe Response. [Figure 10] FIG. 13 is a diagram showing an example of a frame format of a destination link information element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

[0012] FIG. 1 shows the configuration of a network in which a communication device 102 according to this embodiment participates. The communication device 102 is an access point (AP) that has a role of constructing a network 101. The network 101 is a wireless network. In this embodiment, when the communication device 102 constructs multiple networks, the BSSIDs of each network are all different. BSSID stands for Basic Service Set Identifier and is an identifier for identifying a network. Also, the SSIDs indicated by the communication device 102 in each network are all common. Alternatively, the communication device 102 may use a different SSID for each network. SSID stands for Service Set Identifier and is an identifier for identifying an access point.

[0013] The communication device 103 is a station (STA) that has a role of participating in the network 101. Each communication device is compatible with the IEEE802.11be (EHT) standard and can execute wireless communication conforming to the IEEE802.11be standard via the network 101. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. EHT is an abbreviation for Extremely High Throughput. EHT may be interpreted as an abbreviation for Extreme High Throughput. Each communication device can communicate in the frequency bands of 2.4 GHz, 5 GHz, and 6 GHz. The frequency bands used by each communication device are not limited to these, and a different frequency band such as the 60 GHz band may be used. Each communication device can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0014] The communication devices 102 and 103 can realize multi-user (MU) communication in which signals of multiple users are multiplexed by performing OFDMA communication conforming to the IEEE802.11be standard. OFDMA communication is an abbreviation for Orthogonal Frequency Division Multiple Access. In OFDMA communication, a part of the divided frequency band (RU, Resource Unit) is assigned to each STA so as not to overlap, and the carriers assigned to each STA are orthogonal. Therefore, the AP can communicate with multiple STAs in parallel.

[0015] Moreover, the communication devices 102 and 103 execute Multi-Link communication, which establishes links and communicates via multiple frequency channels. Here, the frequency channel is a frequency channel defined in the IEEE 802.11 series standard, and refers to a frequency channel that can execute wireless communication conforming to the IEEE 802.11 series standard. In the IEEE 802.11 series standard, multiple frequency channels are defined in each of the frequency bands of 2.4 GHz, 5 GHz, and 6 GHz. In addition, in the IEEE 802.11 series standard, the bandwidth of each frequency channel is defined as 20 MHz. Note that, by bonding with adjacent frequency channels, a bandwidth of 40 MHz or more may be used in one frequency channel. For example, the communication device 102 can establish a first link 104 with the communication device 103 via a first frequency channel in the 2.4 GHz band and a second link 105 via a second frequency channel in the 5 GHz band, and communicate via both links. In this case, the communication device 102 maintains the second link 105 via the second frequency channel in parallel with the first link 104 via the first frequency channel. In this way, the communication device 102 can improve the throughput of the communication with the communication device 103 by establishing links with the communication device 103 via multiple frequency channels. Note that the communication devices 102 and 103 may establish multiple links of different frequency bands in multi-link communication. For example, the communication devices 102 and 103 may establish a third link in the 6 GHz band in addition to the first link 104 in the 2.4 GHz band and the second link 105 in the 5 GHz band. Alternatively, links may be established via multiple different channels included in the same frequency band. For example, the first link 104 via 1ch in the 2.4 GHz band and the second link 105 via 5ch in the 2.4 GHz band may be established. Note that links of the same frequency band and links of different frequency bands may be mixed.For example, communication devices 102 and 103 may establish a first link 104 via ch 1 in the 2.4 GHz band, a second link 105 via ch 5 in the 2.4 GHz band, and a third link via ch 36 in the 5 GHz band. By establishing multiple connections with communication device 103 using different frequency bands, communication device 102 can communicate with communication device 103 using the other band even when one band is congested, thereby preventing a decrease in throughput in communication with communication device 103.

[0016] In this way, in multi-link communication, the multiple links established by the communication devices 102 and 103 need only have different frequency channels. Note that in multi-link communication, the channel spacing of the frequency channels of the multiple links established by the communication devices 102 and 103 needs only to be at least greater than 20 MHz. Note that, in this embodiment, the communication devices 102 and 103 establish the first link 104 and the second link 105, but three or more links may be established.

[0017] The communication devices 102 and 103 can execute three modes of communication as multi-link communication. One is Asynchronous Mode (Async Mode), in which communication through each link in the multi-link communication is performed asynchronously. Specifically, communication through the first link and communication through the second link are performed at independent timings. Therefore, both the first link and the second link can communicate at a timing that is not related to the timing of communication through the other link. In this case, if the channel interval between the frequency channels (channels) used in each link is narrow, communication through one link affects communication through the other link. Specifically, if the frequency channels between the links are close to each other, communication through one link is detected by the other link through carrier sense, and therefore communication through the other link cannot be performed while communication through one link is being performed. Therefore, in Async Mode, the channel interval between the links is wide. The other mode is Synchronous Mode (Sync Mode), in which communication through multiple links is performed synchronously. Specifically, the first link and the second link start communication at the same timing. In this case, since the communication through each link starts at the same time, the communication through one link is not carrier-sensed by the other link, so the channel interval between the channels used in each link may be narrow. Another mode is Semi-Asynchronous Mode (Semi-Async Mode). In this mode, when data communication is performed through one link, if the frequency channel of the other link is free, the communication through both links is performed synchronously. For example, when the back-off counter of the first link becomes 0, if the frequency channel of the second link is free, the communication through the first link and the second link start at the same timing. In this case, the back-off counter of the second link does not have to be 0.When the backoff counter of the first link becomes 0, if the frequency channel of the second link is not available, only the communication through the first link is started, and the communication through the second link is not started. In this mode, when the communication through multiple links is performed in parallel, the communication through each link is started simultaneously, so the interval between the channels used in each link may be narrow. The communication devices 102 and 103 may select the mode to be used in the multi-link communication based on the channel interval of the established multiple links.

[0018] When performing multi-link communication, at least one of the communication devices 102 and 103 is a device that can simultaneously transmit data via a certain link and receive data via another link. Alternatively, at least one of the communication devices 102 and 103 may be a device that can simultaneously only transmit data via another link when transmitting data via a certain link. Alternatively, at least one of the communication devices 102 and 103 may be a device that can simultaneously only receive data via another link when receiving data via a certain link. Alternatively, at least one of the communication devices 102 and 103 may be a device that can simultaneously maintain multiple links, but cannot simultaneously communicate data via another link when communicating data via a certain link. Note that such a communication device is not compatible with Sync Mode or Semi-Async Mode.

[0019] When performing multi-link communication, the communication devices 102 and 103 divide one piece of data and transmit it to the other device via multiple links. Alternatively, the communication devices 102 and 103 may transmit the same data via each of the multiple links, so that the communication via one link serves as a backup communication for the communication via the other link. Specifically, the communication device 102 transmits the same data to the communication device 103 via a first link via a first frequency channel and a second link via a second frequency channel. In this case, even if an error occurs in the communication via the first link, for example, the communication device 103 can receive the data transmitted from the communication device 102 because the same data is transmitted via the second link. Alternatively, the communication devices 102 and 103 may use different links depending on the type of frame or the type of data to be communicated. For example, the communication device 102 may transmit a management frame via the first link and transmit a data frame including data via the second link. Specifically, management frames refer to Beacon frames, Probe Request frames / Response frames, and Association Request frames / Response frames. In addition to these frames, Disassociation frames, Authentication frames, De-Authentication frames, and Action frames are also called management frames. Beacon frames are frames that report network information. Probe Request frames are frames that request network information, and Probe Response frames are the corresponding responses, providing network information. Association Request frames are frames that request a connection, and Association Response frames are the corresponding responses, indicating permission for connection or an error. Disassociation frames are frames that cut off a connection.An authentication frame is a frame that authenticates a partner device, and a de-authentication frame is a frame that interrupts authentication of a partner device and disconnects the connection. An action frame is a frame for performing additional functions other than those described above. The communication devices 102 and 103 transmit and receive management frames that comply with the IEEE802.11 series standards. Alternatively, when the communication device 102 transmits data related to a captured image, for example, the communication device 102 may transmit meta-information such as date, parameters at the time of capturing an image (aperture value and shutter speed), and location information via a first link, and transmit pixel information via a second link.

[0020] Furthermore, the communication devices 102 and 103 may be capable of performing MIMO (Multiple-Input And Multiple-Output) communication. In this case, the communication devices 102 and 103 have multiple antennas, and one of them transmits different signals from each antenna using the same frequency channel. The receiving side simultaneously receives all signals arriving from multiple streams using multiple antennas, and separates and decodes the signals of each stream. In this way, by performing MIMO communication, the communication devices 102 and 103 can communicate more data in the same time compared to when not performing MIMO communication. Furthermore, the communication devices 102 and 103 may perform MIMO communication in some links when performing multi-link communication.

[0021] In this embodiment, when the communication device 102 is performing multi-link communication with the communication device 103, the communication device 102 can transmit information about the second link 105 to the communication device 103 via the first link 104. The information about the second link 105 is, for example, information indicating a frequency channel used in the second link 105 and whether the frequency channel is busy (occupied). The communication device 103 that has received the information about the second link 105 can use the received information to determine whether to switch the link used for data communication with the communication device 102 from the first link 104 to the second link 105. In this way, the communication device 103 can switch the link used for data communication to a more appropriate one by receiving information about another link established with the communication device 102. In this embodiment, such information about the second link 105 is called destination information of the multi-link communication. Details of the destination information will be described later with reference to FIG. 10.

[0022] In addition, the communication device 102 may transmit information on a link that the device itself can establish with the communication device 103, instead of or in addition to the information on the link already established with the communication device 103. The information on the link that the device itself can establish with the communication device 103 is, for example, information indicating a frequency channel on which the communication device 102 has already established a wireless network and has not yet established a link with the communication device 103. Alternatively or in addition to this, the information may be information indicating whether the frequency channel is busy. In this embodiment, in addition to or in place of the information on the second link 105, these pieces of information may be called destination information of the multi-link communication. Details of these pieces of information will be described later in FIG. 10. By receiving such information, the communication device 103 can establish a new link with the communication device 102 and switch the link used for data communication from the currently used link to the newly established link. In this way, by newly establishing a link to be switched to when switching the link, the power saving of the communication devices 102 and 103 can be improved.

[0023] Although the communication devices 102 and 103 are described as being compatible with the IEEE802.11be standard, they may also be compatible with at least one of the legacy standards that are standards prior to the IEEE802.11be standard. The legacy standards are the IEEE802.11a / b / g / n / ac / ax standards. In this embodiment, at least one of the IEEE802.11a / b / g / n / ac / ax / be standards is called the IEEE802.11 series standard. In addition to the IEEE802.11 series standard, they may also be compatible with other communication standards such as Bluetooth (registered trademark), NFC, UWB, Zigbee, and MBOA. UWB stands for Ultra Wide Band, and MBOA stands for Multi Band OFDM Alliance. OFDM stands for Orthogonal Frequency Division Multiplexing. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNet, etc. It may also be compatible with communication standards for wired communication such as wired LAN.

[0024] Specific examples of the communication device 102 include, but are not limited to, a wireless LAN router and a PC. The communication device 102 may be any communication device capable of performing multi-link communication with other communication devices. The communication device 102 may be an information processing device such as a wireless chip capable of performing wireless communication conforming to the IEEE802.11be standard. Specific examples of the communication device 103 include, but are not limited to, a camera, a tablet, a smartphone, a PC, a mobile phone, a video camera, and the like. The communication device 103 may be any communication device capable of performing multi-link communication with other communication devices. The communication device 103 may be an information processing device such as a wireless chip capable of performing wireless communication conforming to the IEEE802.11be standard. The network in FIG. 1 is a network configured by one AP and one STA, but the number of APs and STAs is not limited to this. The information processing device such as a wireless chip has an antenna for transmitting the generated signal.

[0025] In this embodiment, the communication device 102 is an AP and the communication device 103 is an STA, but this is not limiting, and both the communication devices 102 and 103 may be STAs. In this case, the communication device 102 is an STA, but operates as a device having a role of constructing a wireless network for establishing a link with the communication device 103.

[0026] 2 shows a hardware configuration of the communication device 102 in this embodiment. The communication device 102 includes 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 an antenna 207.

[0027] The storage unit 201 is composed of one or more memories such as a ROM and a RAM, and stores various information such as computer programs for performing various operations described below and communication parameters for wireless communication. ROM stands for Read Only Memory, and RAM stands for Random Access Memory. As the storage unit 201, in addition to memories such as ROM and RAM, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used. Furthermore, the storage unit 201 may include multiple memories.

[0028] The control unit 202 is configured with one or more processors such as a CPU or an MPU, and controls the entire communication device 102 by executing a computer program stored in the storage unit 201. The control unit 202 may control the entire communication device 102 in cooperation with the computer program stored in the storage unit 201 and an OS (Operating System). The control unit 202 also generates data and signals (radio frames) to be transmitted in communication with other communication devices. The CPU stands for Central Processing Unit, and the MPU stands for Micro Processing Unit. The control unit 202 may also include multiple processors such as a multi-core processor, and the entire communication device 102 may be controlled by the multiple processors.

[0029] Furthermore, the control unit 202 controls the functional unit 203 to execute predetermined processes such as wireless communication, imaging, printing, projection, etc. The functional unit 203 is hardware that enables the communication device 102 to execute predetermined processes.

[0030] The input unit 204 receives various operations from the user. The output unit 205 performs various outputs to the user via a monitor screen or a speaker. Here, the output by the output unit 205 may be a display on a monitor screen, a voice output by a speaker, a vibration output, or the like. Note that both the input unit 204 and the output unit 205 may be realized by one module, such as a touch panel. Also, the input unit 204 and the output unit 205 may be integrated with the communication device 102, or may be separate.

[0031] The communication unit 206 controls wireless communication conforming to the IEEE802.11be standard. The communication unit 206 may control wireless communication conforming to other IEEE802.11 series standards in addition to the IEEE802.11be standard, or control wired communication such as wired LAN. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communication generated by the control unit 202. If the communication device 102 supports the NFC standard, Bluetooth standard, or the like in addition to the IEEE802.11be standard, the communication unit 206 may control wireless communication conforming to these communication standards. If the communication device 102 can perform wireless communication conforming to a plurality of communication standards, the communication unit 206 may have a configuration having a communication unit and an antenna corresponding to each communication standard. The communication device 102 communicates data such as image data, document data, and video data with the communication device 103 via the communication unit 206. The antenna 207 may be configured as a separate unit from the communication unit 206, or may be configured as a single module together with the communication unit 206.

[0032] The antenna 207 is an antenna capable of communication in the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. In this embodiment, the communication device 102 has one antenna, but may have a different antenna for each frequency band. In addition, when the communication device 102 has multiple antennas, it may have a communication unit 206 corresponding to each antenna.

[0033] The communication device 103 has the same hardware configuration as the communication device 102 .

[0034] 3 shows a functional configuration of the communication device 102 in this embodiment. The communication device 102 has a multilink communication capability information generation unit 301, a multilink communication operation information determination unit 302, and a multilink communication destination information generation unit 307. In addition to these, the communication device 102 has a connection processing unit 304, a MAC (Media Access Control) frame generation unit 305, and a data transmission / reception unit 306.

[0035] Capability information generating section 301 is a block that generates capability information related to multilink communication of communication device 102. Communication device 102 generates capability information for notifying other communication devices of its own capability related to multilink communication. Capability information related to multilink communication will be described later with reference to FIG. 5. Note that the capability information may be notified of the capability information of the own device to other communication devices, or it may simply receive capability information of the other device from the other communication device.

[0036] The operation information determination unit 302 is a block that determines operation information regarding multilink communication with a partner device based on capability information regarding multilink communication of the own device and the partner device. Operation information regarding multilink communication refers to frequency channels and bandwidths used in communication executed as multilink communication between the communication devices 102 and 103. Details of the operation information regarding multilink communication will be described later with reference to FIG. 5. Regarding the operation information, the determined operation information may or may not be notified to the partner device.

[0037] The connection processing unit 304 is a block that performs processing for allowing the communication device 103, which is an STA, to participate in the network 101 constructed by the communication device 102. Specifically, the connection processing unit 304 causes the communication device 102 to transmit an Association Response frame as a response to an Association Request, which is a connection request received from the communication device 103. The communication device 102 has a connection processing unit 304 corresponding to each of a plurality of links that the communication device 102 establishes.

[0038] The MAC frame generating unit 305 is a block that generates a MAC frame including information indicating capability information related to multilink communication generated by the capability information generating unit 301 and information indicating operational information related to multilink communication determined by the operational information determining unit 302. Also, the MAC frame generating unit 305 generates a MAC frame including information indicating destination information related to multilink communication generated by a destination information generating unit 307 described later. The MAC frame generated by the MAC frame generating unit 305 is transmitted by being included in at least one of a beacon, a probe response, and an association response wireless frame. In addition to this, or instead, the generated MAC frame is transmitted by being included in a reassociation response. The capability information and operational information included in the MAC frame generated by the MAC frame generating unit 305 are indicated by an Element shown in FIG. 5 described later. Also, the destination information included in the MAC frame generated by the MAC frame generating unit 305 is indicated by an Element shown in FIG. 10 described later.

[0039] The data transmitter / receiver unit 306 is a block that transmits and receives data frames in multi-link communication based on the operation information related to the multi-link communication determined by the operation information determination unit 302. The data transmitter / receiver unit 306 may transmit a wireless frame including a MAC frame generated by the MAC frame generation unit 305 and receive a wireless frame from a partner device.

[0040] The destination information generating unit 307 is a block that generates information about other links in the multi-link communication that the communication device 102 transmits to the communication device 103. The communication device 102 generates information about a link that is established between the communication device 102 and the communication device 103 and is different from the link used to transmit the information. The information about the other link will be described later with reference to FIG. 10. Note that, as the information about the other link, information about a link that can be established with the communication device 103 in the future may be generated. The information about the link that can be established with the communication device 103 in the future is information about a link that has not yet been used to establish a link with the communication device 103 but can be established via a wireless network that the communication device 102 has constructed. In addition to the information about the other link, information about the link used to transmit the information may be generated as information to be transmitted to the communication device 103.

[0041] The communication device 103 has the same functional configuration as the communication device 102, but differs in the following respects.

[0042] The communication device 103 has a request information determination section 302 instead of the operation information determination section 302. This is a block that determines request information regarding multilink communication with a partner device based on capability information regarding multilink communication of the own device and the partner device. The request information regarding multilink communication refers to a frequency channel, a bandwidth, and the like that are requested to be used in communication executed as multilink communication between the communication devices 102 and 103. Details of the request information regarding multilink communication will be described later with reference to FIG. 5. The communication device 103 may or may not notify the partner device of the determined request information.

[0043] The connection processing unit 304 is a block that performs processing for the communication device 103 to join the network 101 established by the communication device 102 that is an AP. Specifically, the connection processing unit 304 causes the communication device 103 to transmit an Association Request, which is a connection request, to the communication device 102, and to receive an Association Response as a response from the communication device 102.

[0044] Further, the MAC frame generating unit 305 is a block that generates a MAC frame including information indicating capability information related to multilink communication generated by the capability information generating unit 301 and request information related to multilink communication determined by the request information determining unit 302. The MAC frame generated by the MAC frame generating unit 305 is transmitted by being included in at least one of a Probe Request, an Association Request, and a Reassociation Request wireless frame. The capability information and request information included in the MAC frame generated by the MAC frame generating unit 305 are indicated by an Element shown in Fig. 5 described later.

[0045] Furthermore, the communication device 103 does not need to include the destination information generating unit 307 .

[0046] FIG. 4 is a sequence diagram showing an example of a process executed when the communication device 102 and the communication device 103 establish a link for multi-link communication.

[0047] The communication devices 102 and 103 each have a connection processing unit 304 internally corresponding to each of a plurality of links. AP1 of the communication device 102 is a connection processing unit 304 for the first link, and AP2 is a connection processing unit 304 for the second link. Also, STA1 of the communication device 103 indicates a connection processing unit 304 for the first link, and STA2 indicates a connection processing unit 304 for the second link. STA1 and AP1 process communication via a first frequency channel (e.g., 1ch in the 2.4 GHz band). STA2 and AP2 process communication via a second frequency channel (e.g., 36ch in the 5 GHz band).

[0048] The process of this sequence is started in response to the power being turned on for each of the communication devices 102 and 103. Alternatively, at least one of the communication devices 102 and 103 may start the process in response to an instruction to start multilink communication from a user or an application. Alternatively, at least one of the communication devices 102 and 103 may start the process in response to the amount of data to be communicated with the other device reaching or exceeding a predetermined threshold.

[0049] First, the communication device 102 transmits a Beacon including its own network information on a first frequency channel to notify surrounding STAs of the network information (S401). Specifically, the network information is a transmission interval at which the communication device 102 transmits a beacon and the SSID of the communication device 102. In addition, the communication device 102 may include a Multi-Link Capability Element shown in Fig. 5, which will be described later, in the Beacon as network information to notify capability information related to the multi-link communication of the communication device 102.

[0050] When the communication device 103 receives a Beacon from the communication device 102 transmitted on the first frequency channel, the communication device 103 transmits a Probe Request on the first frequency channel in order to inquire about network information of the communication device 102 (S402). The Probe Request includes the SSID of the communication device 103. In addition to this, the communication device 103 may notify capability information related to multi-link communication of the communication device 103 by including a Multi-Link Capability Element shown in Fig. 5 described later in the Probe Request.

[0051] When the communication device 102 receives the Probe Request, it transmits a Probe Response to the communication device 103 in response on the first frequency channel (S403). If the communication device 102 does not include the Multi-Link Capability Element shown in Fig. 5 in the Beacon, it transmits the Probe Response by including the Element. Alternatively, the communication device 102 may include only a part of the information included in the Multi-Link Capability Element shown in Fig. 5 (described later) in the Beacon, and include the remaining information or all of the information in the Probe Response.

[0052] By performing the processes of S401 to S403, the communication devices 102 and 103 can exchange capability information related to their respective multilink communications. Furthermore, the communication device 102 can indicate destination information in multilink communications by including a destination information element shown in FIG. 10, which will be described later, in the Beacon transmitted in S401. The communication device 102 may include a destination information element in the Probe Response transmitted in S403 in addition to or instead of the Beacon. Note that the communication device 102 includes a destination information element in at least one of the Beacon and the Probe Request after establishing at least one link of multilink communications with the communication device 103. In this case, if the communication device 102 has not established any link of multilink communications with the communication device 103, it transmits a Beacon and a Probe Response that do not include destination information. Alternatively, even if the communication device 102 has not established any multi-link communication link with the communication device 103, the communication device 102 may include destination information indicating information regarding a link that can be established with the communication device 103.

[0053] Next, the communication device 103 transmits an Association Request, which is a connection request, to the communication device 102 on the first frequency channel. In this case, the communication device 103 may notify the communication device 102 of capability information related to the multi-link communication by including a Multi-Link Capability Element shown in FIG. 5 in the Association Request. The communication device 103 may determine capability information to be transmitted in S404 based on capability information related to the multi-link communication of the communication device 102 acquired in at least one of S401 and S403. For example, even if the communication device 103 can combine links in the 2.4 GHz band and the 5 GHz band in the multi-link communication, the communication device 102 only supports multiple links in the 2.4 GHz band. In this case, the communication device 103 may transmit only capability information related to the establishment of multiple links in the 2.4 GHz band as capability information to be transmitted in this step. In this embodiment, the communication device 103 transmits capability information related to the multi-link communication of the own device in S402, but the present invention is not limited to this, and the capability information may not be transmitted in S402, but may be transmitted only in this step. Alternatively, the communication device 103 may transmit request information requested when performing multi-link communication, instead of capability information, by including a Multi-Link Capability Element shown in Fig. 5 in the Association Request. The request information requested by the communication device 103 may be indicated by the Multi-Link Capability Element in Fig. 5, or may be indicated by another Element. Details of the request information will be described later with reference to Fig. 5.

[0054] When the communication device 102 receives the Association Request, it transmits an Association Response to the communication device 103 in response on the first frequency channel (S405). The Association Response transmitted here includes a Multi-Link Capability Element indicating operation information determined by the communication device 102 when performing multi-link communication with the communication device 103. Note that the operation information may be indicated by an element different from the Multi-Link Capability Element. Furthermore, if the communication device 103, which is the STA, has transmitted an Association Request including operation information requested in S404, the communication device 102 may transmit an Association Response including only the availability of the request.

[0055] If the communication device 103 can perform multi-link communication using the operation information included in the Association Response, the communication devices 102 and 103 establish a link via the first frequency channel and start data communication (S406). In this case, if the operation information transmitted by the communication device 102 includes operation information for a link via a second frequency channel, the communication devices 102 and 103 also establish a link via the second frequency channel and start data communication (S407).

[0056] Note that the process of S406 is also performed when the communication device 102 indicates permission in S405 for the request information requested in S404 to the communication device 103. In addition, when the request information transmitted by the communication device 103 in S404 also includes request information regarding a link via the second frequency channel, the process of S407 is performed.

[0057] In this embodiment, two links are established by transmitting and receiving frames on one frequency channel, but the present invention is not limited to this, and three or more links may be established.

[0058] In the present embodiment, the case where multi-link communication is started when no link has been established between the communication devices 102 and 103 has been described, but the present invention is not limited to this. The communication devices 102 and 103 may start link communication by establishing a new link in addition to the already established link. In this case, the communication device 103, which is an STA, may start from the process of S404 when it has already acquired capability information related to the multi-link communication of the communication device 102, which is an AP. Alternatively, the communication device 102 may start from the process of S404 by transmitting a signal to the communication device 103 to transmit an Association Request when it has already acquired capability information related to the multi-link communication of the communication device 103. Alternatively, the communication devices 102 and 103 may establish a new link in addition to the multiple links that have already been established. In this case, the sequence of FIG. 4 may also start from S404.

[0059] The communication device 102 transmits a Beacon at predetermined time intervals. The communication device 103 can determine whether to switch the link for data communication with the communication device 102 from the currently used link to another link based on the destination information included in the Beacon transmitted at predetermined time intervals. The communication device 102 also transmits a Probe Response in response to a Probe Request transmitted from the communication device 103. The communication device 103 may transmit a Probe Request to the communication device 102 not only to inquire about the network information of the communication device 102 but also to obtain destination information.

[0060] Fig. 5 is a diagram showing an example of a frame format of a Multi-Link Capability Element. Note that, in this embodiment, the name of the element shown in Fig. 5 is Multi-Link Capability Element, but is not limited thereto and may be another name such as Multi-Link Element.

[0061] The communication devices 102 and 103 can notify the other device of capability information indicating the capability of the device in multi-link communication by using the Multi-Link Capability Element shown in Fig. 5. Also, the communication device 102 can notify the other device of operation information when performing multi-link communication in addition to or instead of the capability information by using the Multi-Link Capability Element shown in Fig. 5. Also, the communication device 103 can notify the other device of request information when performing multi-link communication in addition to or instead of the capability information by using the Multi-Link Capability Element shown in Fig. 5.

[0062] The Multi-Link Capability Element shown in FIG. 5 includes an Element ID 501, a Length 502, and ML (Multi-Link) Capabilities 503. The Element ID 501 is an identifier for identifying an Information Element, and in this embodiment, includes an identifier indicating a Multi-Link Capability Element. The Length 502 is a field indicating the data length of an Element, and in this embodiment, includes information indicating the data length of ML Capabilities 503. The ML Capabilities 503 is information specific to the Multi-Link Capability Element, and includes information related to multi-link communication. Details of the information included in the ML Capabilities 503 will be described later.

[0063] The communication devices 102 and 103 generate the Multi-Link Capability Elements shown in FIG. 5 in order starting from Element ID 501, and transmit them to other communication devices. In this case, the communication devices 102 and 103 generate all fields in the frame before transmitting. Specifically, the communication devices 102 and 103 generate all of Element ID 501, Length 502, and ML Capabilities 503 before transmitting them to other communication devices. Alternatively, the communication devices 102 and 103 may generate and transmit fields in parallel. Specifically, the communication devices 102 and 103 may transmit, for example, the generated Element ID 501 and Length 502 in parallel.

[0064] The communication device 102, which is an AP, adds a MAC frame including a Multi-Link Capability Element to wireless frames such as a Beacon and a Probe Response and transmits the MAC frame. In addition to these wireless frames, the communication device 102 can also add a MAC frame including this Element to wireless frames such as an Association Response and a Reassociation Response. The communication device 103, which is an STA, adds a MAC frame including a Multi-Link Capability Element to wireless frames such as a Probe Request and an Association Request and transmits the MAC frame. In addition to these wireless frames, the communication device 103 can also add a MAC frame including this Element to a Reassociation Request.

[0065] ML Capabilities 503 includes Common Info 511, Per Band Info 512, and Per Link Info 513. Common Info 511 is a field indicating information common to all frequency bands and links. Per Band Info 512 is a field indicating information common to all links included in a specific frequency band, and is information indicated for each frequency band. Per Link Info 513 is a field indicating information for each link.

[0066] Common Info 511 includes Primary Ch 521, Sync Mode Support 522, Async Mode Support 523, and Semi-Async Mode Support 528. Common Info 511 further includes Total Max Link Number 524, Band Combination Info 525, and Per Band Info Number 526. Common Info 511 further includes Per Link Info Number 527, and Device Type 529.

[0067] The Primary CH 521 is a field including information indicating a frequency channel for transmitting and receiving management frames related to multi-link communication. The Primary CH is a frequency channel used for transmitting and receiving management frames when connecting and disconnecting links in multi-link communication. Specifically, information indicating a frequency channel for transmitting and receiving a beacon including a Multi-Link Capability Element is included. The communication device 102, which is an AP, includes information indicating a frequency channel for transmitting and receiving a beacon including a Multi-Link Capability Element. The communication device 103, which is an STA, includes information indicating a frequency channel for receiving a beacon including a Multi-Link Capability Element (i.e., for transmitting a Probe Request including the Element). In this embodiment, information indicating a first frequency channel for transmitting and receiving a beacon or a Probe Request / Response in FIG. 4 is included. Note that if the frequency channel for transmitting and receiving management frames is changed after the communication devices 102 and 103 start multi-link communication, the Primary CH 521 includes information on the frequency channel corresponding to the change. It should be noted that Primary CH 521 includes information indicating the frequency channel in which the management frame is transmitted and received, regardless of whether the element indicates capability information, operational information, or request information.

[0068] Sync Mode Support 522 is a field that includes capability information indicating whether the communication device 102 or 103 that transmits the Element supports Sync Mode for multi-link communication. For example, if this field contains 0, the transmitting device of the Element does not support Sync Mode, and if it contains 1, it supports Sync Mode.

[0069] When the operation information is indicated by the Multi-Link Capability Element, the Sync Mode Support 522 may indicate whether or not to execute the Sync Mode of the multi-link communication. For example, when the communication device 102 transmits an Association Response including this Element, this field indicates whether or not to execute the Sync Mode in the communication of the link established by the exchange of this association. In this case, for example, when this field contains 0, it indicates that the multi-link communication in the Sync Mode is not executed, and when this field contains 1, it indicates that the multi-link communication in the Sync Mode is executed.

[0070] Alternatively, when request information is indicated by the Multi-Link Capability Element, Sync Mode Support 522 may indicate whether or not to request execution of Sync Mode in multi-link communication. For example, when the communication device 103, which is an STA, transmits an Association Request including this element, this field indicates whether or not the communication device 103 requests execution of Sync Mode in multi-link communication. For example, when this field contains 0, it indicates that execution of multi-link communication in Sync Mode is not requested, and when this field contains 1, it indicates that execution of multi-link communication in Sync Mode is requested.

[0071] Async Mode Support 523 is a field that includes capability information indicating whether the communication device 102 or 103 that transmits the Element supports the Async Mode of Multi-Link communication. For example, if this field includes 0, the transmitting device of the Element does not support the Async Mode, and if this field includes 1, it indicates that the transmitting device supports the Async Mode.

[0072] In addition, when the operation information is indicated by the Multi-Link Capability Element, the Async Mode Support 523 may indicate whether or not the Async Mode of the Multi-Link communication is executed. For example, when the communication device 102 transmits an Association Response including this Element, this field indicates whether or not the Async Mode is executed in the Link established by the exchange of this association. In this case, for example, when this field contains 0, it indicates that the Multi-Link communication in the Async Mode is not executed, and when this field contains 1, it indicates that the Multi-Link communication in the Async Mode is executed. In addition, when the operation information is indicated by the Element, if the Sync Mode Support 522 indicates that the Sync Mode is executed, this field indicates that the Async Mode is not executed. Similarly, when the Sync Mode Support 522 indicates that the Sync Mode is not executed, the Async Mode Support 523 indicates that the Async Mode is executed.

[0073] Alternatively, when request information is indicated by the Multi-Link Capability Element, Async Mode Support 523 may indicate whether or not to request execution of Async Mode in multi-link communication. For example, when the communication device 103, which is an STA, transmits an Association Request including this element, this field indicates whether or not the communication device 103 requests execution of Async Mode in multi-link communication. For example, when this field contains 0, it indicates that execution of multi-link communication in Async Mode is not requested, and when this field contains 1, it indicates that execution of multi-link communication in Async Mode is requested.

[0074] Semi-Async Mode Support 528 is a field that includes capability information indicating whether the communication device 102 or 103 that transmits the Element supports Semi-Async Mode of Multi-Link communication. For example, if this field includes 0, the transmitting device of the Element does not support Semi-Async Mode, and if it includes 1, it supports Semi-Async Mode.

[0075] When the operation information is indicated by the Multi-Link Capability Element, this field may indicate whether or not to execute the Semi-Async Mode of the multi-link communication. For example, when the communication device 102 transmits an Association Response, this field indicates whether or not to execute the Semi-Async Mode in the communication of the link established by the exchange of this association. For example, when this field contains 0, it indicates that the multi-link communication in the Semi-Async Mode is not executed. Also, for example, when this field contains 1, it indicates that the multi-link communication in the Semi-Async Mode is executed.

[0076] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may indicate whether or not to request execution of multi-link communication in Semi-Async Mode. For example, when the communication device 103, which is an STA, transmits an Association Request, this field indicates whether or not the communication device 103 requests execution of Semi-Async Mode in multi-link communication. For example, when this field contains 0, it indicates that execution of multi-link communication in Semi-Async Mode is not requested. Also, for example, when this field contains 1, it indicates that execution of multi-link communication in Semi-Async Mode is requested.

[0077] Note that, when the communication devices 102 and 103 perform multi-link communication, if it is preset which of the Sync Mode, the Async Mode, and the Semi-Async Mode to use, these fields may be omitted. Specifically, Sync Mode Support 522, Async Mode Support 523, and Semi-Async Mode Support 528 may be omitted.

[0078] The Total Max Link Number 524 is a field containing capability information indicating the maximum number of links that the communication device 102 or 103 transmitting the Element supports in multi-link communication. The maximum number of links is the maximum number of links that the transmitting device of the Element can establish with one other device. For example, if the value of this field is 3, it is indicated that the transmitting device of the Element can establish up to three links with one other device. In this case, the transmitting device of the Element may maintain multiple links with another other device in parallel with maintaining three links with one other device. Alternatively, the maximum number of links may indicate the maximum number of links that the transmitting device of the Element can establish in multi-link communication, regardless of the other device. In this case, for example, if the value of this field is 3 and the transmitting device of the Element has established three links with the other device, the transmitting device cannot establish any more links regardless of the other device. The communication device 102, which is an AP, and the communication device 103, which is an STA, each contain information indicating the maximum number of links that their own device can simultaneously maintain in multi-link communication in this field.

[0079] When the operation information is indicated by the Multi-Link Capability Element, this field may include the number of links that are actually established in the multi-link communication. For example, when the communication device 102, which is an AP, transmits an Association Response including this Element, this field indicates the number of links that are established by the exchange of this association. Alternatively, the maximum number of links that can be established in the multi-link communication with the communication device 103 may be included. In this case, Total Max Link Number 524 includes a value equal to or less than the smaller value of the maximum number of links that the own device can establish in the multi-link communication and the maximum number of links that the other device can establish.

[0080] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may include the number of links requested to be established in multi-link communication. For example, when communication device 103, which is an STA, transmits an Association Request including this element, this field indicates the number of links that communication device 103 requests communication device 102 to establish. Alternatively, it may include the maximum number of links that can be established in multi-link communication with communication device 102. Note that, when operational information or request information is indicated by a Multi-Link Capability Element, this field may be omitted.

[0081] Band Combination Info 525 is a field including capability information indicating the frequency bands supported by the communication device 102 or 103 transmitting the Element during multilink communication. Table 1 shows an example of information indicated by each bit of this field. In Table 1, it is arranged to indicate which frequency band or what combination of frequency bands is supported for each bit. In this embodiment, if the corresponding bit contains 0, it indicates that the multilink communication in the content indicated by that bit is not supported, and if the corresponding bit contains 1, it indicates that the multilink communication in the content indicated by that bit is supported. For example, if bit 0 in Band Combination Info 525 transmitted by the communication device 102 contains 1, it indicates that the communication device 102 supports multilink communication in different channels in the 2.4 GHz band. Also, for example, if the value of Band Combination Info 525 is 0000111000, it indicates that the communication device 102 supports multilink communication using multiple links with different frequency bands. In this case, it is indicated that the communication device 102 does not support multilink communication using multiple links with the same frequency band. Moreover, by setting all bits of Band Combination Info 525 to 0, it may be indicated that the transmitting device of the Multi-Link Capability Element does not support Multi-Link communication. Alternatively, it may be indicated that the transmitting device of the Element is currently in a state in which it cannot execute multi-link communication. Note that the communication devices 102 and 103 may support different frequency bands in communication using only one link and in multi-link communication. For example, the communication devices 102 and 103 may support all of 2.4 GHz, 5 GHz, and 6 GHz in communication using only one link, but may support only 5 GHz and 6 GHz in multi-link communication. Note that the correspondence between each bit of Band Combination Info 525 and its contents is not limited to that shown in Table 1.Moreover, by increasing the number of bits of Band Combination Info 525, it may be possible to indicate more combinations of frequency bands or whether or not multiple links can be established in different frequency bands.

[0082] [Table 1]

[0083] When the operation information is indicated by the Multi-Link Capability Element, this field may indicate the frequency band actually used in the multi-link communication. For example, when the communication device 102, which is an AP, transmits an Association Response including this element, this field includes information indicating the frequency band of the link established by the exchange of this association. For example, when the communication devices 102 and 103 establish a 2.4 GHz link and a 5 GHz link, the value of Band Combination Info 525 is 00001000.

[0084] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may indicate a frequency band requested for use in multi-link communication. For example, when the communication device 103, which is an STA, transmits an Association Request including this Element, this field indicates a frequency band for which the communication device 103 requests the communication device 102 to execute multi-link communication. Note that even when operation information or request information is indicated by this Element, this field may include capability information indicating a frequency band supported by the transmitting device of the Element in multi-link communication.

[0085] Per Band Info Number 526 is a field including information indicating the number of Per Band Info included in Per Band Info 512 described later. Per Band Info 512 includes a set of Per Band Info for each frequency band supported in multi-link communication by the communication device 102 or 103 transmitting the Multi-Link Capability Element. Specifically, information indicating the same number as the number of frequency bands indicated in Band Combination Info 525 is included. Note that this does not apply when information on a plurality of frequency bands is indicated by a common Per Band Info in Per Band Info 512 described later. Also, when Per Band Info 512 described later is omitted, this field is also omitted.

[0086] Per Link Info Number 527 is a field that includes information indicating the number of Per Link Info included in Per Link Info 513 described later. Per Link Info 513 includes a set of Per Link Info for each link supported in multi-link communication by the communication device 102 or 103 that transmits the Multi-Link Capability Element. When Per Link Info 513 described later is omitted, this field is also omitted.

[0087] The Device Type 529 is a field that includes capability information indicating what type of device the communication device 102 or 103 that transmits the Element is in multi-link communication. Specifically, information indicating which of the following four types of devices the transmitting device of the Element is is included. The first type of device is a device that can simultaneously transmit data via a certain link and receive data via another link in multi-link communication. The second type of device is a device that can simultaneously transmit data only via another link when transmitting data via a certain link. The third type of device is a device that can simultaneously receive data only via another link when receiving data via a certain link. The fourth type of device is a device that can simultaneously maintain multiple links, but cannot simultaneously communicate data via one link when communicating data via another link.

[0088] When the operation information is indicated by the Multi-Link Capability Element, the Device Type 529 may indicate which type of device both devices will operate as in the multi-link communication. For example, when the communication device 102 transmits an Association Response including this element, this field indicates which type of device the device will operate as in the communication of the link established by the exchange of this association. For example, when information indicating the second type is transmitted as the operation information, the communication device 102 operates as a second type device in the communication of the link established by the exchange of this association, even if it is a device that can operate as the first type.

[0089] Alternatively, when request information is indicated by the Multi-Link Capability Element, Device Type 529 may indicate what type of device the communication device 103 is requested to operate as in multi-link communication. For example, when the communication device 103, which is an STA, transmits an Association Request including this element, this field indicates what type of device the communication device 103 wishes to operate as in multi-link communication. For example, when information indicating the second type is included in this field, it indicates that the communication device 103 requests to operate as a second type of device in multi-link communication with the communication device 102.

[0090] Per Band Info 512 is a field including Band ID 531, Supported Bandwidth 532, Supported CH 533, and Async Mode CH Distance 534. In addition to these fields, Per Band Info 512 further includes Max Link Number 535 and Supported Nss 536. A set of Per Band Info 512 is included in a Multi-Link Capability Element for each frequency indicated by Band ID 531, which will be described later.

[0091] Band ID 531 is a field including information for identifying a frequency band. Table 2 shows an example of the correspondence between the value included in Band ID 531 and the contents indicated by the value. For example, when Band ID 531 includes a value of 0, Per Band Info 512 including this Band ID 531 is information indicating information common to the Links of multi-link communication in the 2.4 GHz band. Note that the correspondence between the value included in Band ID 531 and the contents indicated is not limited to this. Also, the number of bits of Band ID 531 may be increased to indicate more frequency bands.

[0092] [Table 2]

[0093] Supported Bandwidth 532 is a field including capability information indicating a bandwidth supported by the communication device 102 or 103 that transmitted the Element in the frequency band indicated by Band ID 531. The bandwidth indicated here is information indicating a bandwidth supported per link when the transmitting device of the Element performs multilink communication in the frequency band indicated by Band ID 531. Table 3 shows an example of a correspondence relationship between the value included in Supported Bandwidth 532 and the contents indicated by the value. For example, when Supported Bandwidth 532 includes a value of 0, it is indicated that the bandwidth supported by the transmitting device of the Element in the frequency band indicated by Band ID 531 is 20 MHz. When the value of Supported Bandwidth 532 is 1 or more, the transmitting device of the Element can support any bandwidth equal to or less than the value when establishing a link for multilink communication. For example, when the value of Supported Bandwidth 532 is 2, the transmitting device supports any of 20 MHz, 40 MHz, and 80 MHz as the bandwidth of the link. The communication devices 102 and 103 may support different bandwidths in communication using only one link and in multi-link communication. For example, the communication devices 102 and 103 may support a bandwidth of 80 MHz at 5 GHz in communication using only one link, but may support a bandwidth of 20 MHz in multi-link communication. The correspondence between the values ​​included in the Supported Bandwidth 532 and the contents indicated by them is not limited to this. Also, the number of bits in the Supported Bandwidth 532 may be increased to indicate more frequency bands.

[0094] [Table 3]

[0095] When the operation information is indicated by the Multi-Link Capability Element, this field may indicate the bandwidth actually used in the multi-link communication. For example, when the communication device 102, which is an AP, transmits an Association Response including this Element, this field includes information indicating the bandwidth of the link established by the exchange of this association. For example, when the communication devices 102 and 103 establish a link with a bandwidth of 40 MHz at 2.4 GHz, the value of Supported Bandwidth 532 is 1.

[0096] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may indicate the bandwidth requested for use in multi-link communication. When the communication device 103, which is an STA, transmits an Association Request including this Element, this field indicates the bandwidth requested by the communication device 103 to the communication device 102. Note that even when operational information or request information is indicated by this Element, this field may include capability information indicating the bandwidth supported by the transmitting device of the Element in multi-link communication.

[0097] Supported CH533 is a field including capability information indicating channels supported by the communication device 102 or 103 that transmitted the Element in the frequency band indicated by Band ID531. The channel indicated here is information indicating channels that the transmitting device of the Element supports in the frequency band indicated by Band ID531 for multilink communication. Table 4 shows an example of the correspondence between each bit of Supported CH533 and the channel indicated by the bit. For example, when a bit includes a value of 0, it indicates that the transmitting device of the Element does not support the channel indicated by the bit, and when a bit includes a value of 1, it indicates that the transmitting device supports the channel indicated by the bit. For example, when Supported CH533 includes a value of 0000010010100, it indicates that the transmitting device of this field supports multilink communication in 3ch, 5ch, and 8ch. Note that the communication devices 102 and 103 may support different channels in communication with only one link and in multilink communication. For example, the communication devices 102 and 103 may support all of 1-13ch in communication with only one link, but may support only some channels such as 1ch and 5ch in multi-link communication. The correspondence between each bit of SupportedCH533 and its contents is not limited to that shown in Table 4. In addition, by increasing the number of bits of SupportedCH533, more channels may be indicated. For example, in Table 4, only channels at 2.4GHz are shown as an example, but by increasing the number of bits, each channel at 5GHz and 6GHz may be indicated from 13th bit onwards. Alternatively, if information indicating 5GHz is included in Band ID531, each channel at 5GHz may be indicated in ascending order starting from 0 bit. Similarly, if Band ID531 includes 6GHz, each channel at 6GHz may be indicated in descending order starting from 0 bit.

[0098] [Table 4]

[0099] In addition, when the operation information is indicated by the Multi-Link Capability Element, this field may indicate the channel actually used in the multi-link communication. For example, when the communication device 102, which is an AP, transmits an Association Response including this Element, this field includes information indicating the channel of the link established by the exchange of this association. For example, when the communication devices 102 and 103 establish links of 1ch and 4ch at 2.4GHz, the value of Supported CH533 is 0000000001001.

[0100] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may indicate a channel requested to be used in multi-link communication. For example, when the communication device 103, which is an STA, transmits an Association Request including this Element, this field indicates a channel for which the communication device 103 requests the communication device 102 to establish a link. Note that, even when the operation information or request information is indicated by this Element, this field may include capability information indicating a channel supported by the transmitting device of the Element in multi-link communication.

[0101] Async Mode CH Distance 534 is a field including capability information indicating the channel spacing required in Async Mode by a transmitting device that transmitted the Element in the frequency band indicated by Band ID 531. In Async Mode, communication of each link is performed asynchronously, so if the channels used in each link are close to each other, there is a risk of communication interference. The distance between the channels between the links required to properly decode the signals of each link varies depending on the communication device, so this field is used to notify capability information. For example, if Async Mode CH Distance 534 includes a value of 4, it is indicated that the transmitting device of the Element requires a channel spacing of at least 4ch or more in Async Mode. Note that, if the above-mentioned Async Mode Support 523 includes information indicating that Async Mode is not supported, this field may include a value of 0, or this field may be omitted. In this embodiment, the channel spacing required in Async Mode is indicated for each frequency band indicated by Band ID 531, but this is not limited to this, and information common to each frequency band may be used. Specifically, this field may be included in Common Info 511.

[0102] When the operation information is indicated by the Multi-Link Capability Element, this field may contain information indicating the interval of the channels actually used in the Async Mode of the multi-link communication. For example, when the communication device 102, which is an AP, transmits an Association Response including this Element, this field contains information indicating the channel interval of the multiple links established by the exchange of this association.

[0103] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may include information indicating the interval of the channel requested to be used in the Async Mode of the multi-link communication. Information indicating the minimum channel interval supported in the Async Mode of the multi-link communication with the other device may be included. When operation information is indicated by the Element, this field includes a value equal to or greater than the larger channel interval between the channel interval indicated by the communication device 102 as the capability information and the channel interval indicated by the communication device 103 as the capability information. Also, when the Async Mode Support 523 includes information indicating that the Async Mode is not executed, or when the Async Mode Support 523 is omitted, this field may include a value of 0. Alternatively, this field may be omitted. Alternatively, when the communication device 103, which is an STA, transmits an Association Request including this Element, this field indicates the channel interval requested by the communication device 103 in the Async Mode with the communication device 102. Note that, when the communication device 103 does not request the execution of the Async Mode, this field may include a value of 0 or may be omitted. When the operation information or request information is indicated by the Multi-Link Capability Element, this field may be omitted.

[0104] Max Link Number 535 is a field including capability information indicating the maximum number of links supported by the transmitting device that transmitted the Element when performing multi-link communication in the frequency band indicated by Band ID 531. If the above-mentioned Band Combination Info 525 does not include information indicating that multi-link communication between links in the same frequency band is supported, this field may include a value of 0. Alternatively, this field may be omitted. In addition, in this embodiment, the maximum number of links can be indicated for each frequency band, but this is not limited to the above, and the maximum number of links may be indicated as information common to all frequency bands. Specifically, this field may be included in Common Info 511.

[0105] When operation information is indicated by a Multi-Link Capability Element, this field may indicate the total number of links actually used in multi-link communication in the frequency band indicated by Band ID 531. For example, when the communication device 102, which is an AP, transmits an Association Response including this Element, this field includes information indicating the number of links, one or more, established by the exchange of this association. For example, when the communication devices 102 and 103 establish two links at 2.4 GHz, this field includes a value of 2.

[0106] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may indicate the total number of links requested to be used in multi-link communication in the frequency band indicated by Band ID 531. For example, when communication device 103, which is an STA, transmits an Association Request including this Element, this field indicates the number of links that communication device 103 requests communication device 102 to establish. Note that even when operational information or request information is indicated by this Element, this field may include capability information indicating the maximum number of links in multi-link communication by the transmitting device of this Element.

[0107] Supported Nss 536 is a field including capability information indicating the maximum number of (spatial) streams supported by the transmitting device that transmitted the Element when performing multilink communication in the frequency band indicated by Band ID 531. Note that Nss is an abbreviation for Number Of Special Stream. The number of streams indicated in this field is the number of streams in MIMO communication. Note that, if MIMO communication is not supported in multilink communication in the frequency band indicated by Band ID 531, this field includes a value of 0 or 1, or this field is omitted. In addition, in this embodiment, the maximum number of streams can be indicated for each frequency band, but this is not limited to this, and the maximum number of streams may be indicated as information common to all frequency bands. Specifically, this field may be included in Common Info 511.

[0108] When the operation information is indicated by the Multi-Link Capability Element, this field may indicate the number of streams actually used in the frequency band indicated by the Band ID 531 in the multi-link communication. For example, when the communication device 102, which is an AP, transmits an Association Response including this Element, this field includes information indicating the number of streams of the MIMO communication actually performed by the exchange of this association. For example, when the communication devices 102 and 103 perform MIMO communication with three streams in a link for multi-link communication at 2.4 GHz, this field includes a value of 3. When MIMO communication is not performed, this field may include a value of 0 or 1, or this field may be omitted.

[0109] Alternatively, when request information is indicated by the Multi-Link Capability Element, this field may indicate the number of streams requested for use in the frequency band indicated by Band ID 531 in multi-link communication. When the communication device 103, which is an STA, transmits an Association Request including this Element, this field indicates the number of streams requested by the communication device 103 in MIMO communication in multi-link communication. Note that, when the communication device 103 does not request MIMO communication, this field may include a value of 0 or 1, or this field may be omitted. Also, even when the operation information or request information is indicated by the Element, this field may include capability information indicating the maximum number of streams supported by the transmission device of the Element in MIMO communication in multi-link communication.

[0110] Per Link Info513 is a field including each of the fields Link ID541, Band ID542, Bandwidth543, CH544, and Nss545. When capability information is indicated by a Multi-Link Capability Element, Per Link Info513 indicates information on channels for which the transmission device of the Element supports multi-link communication. In this case, the set of Per Link Info513 includes the number of channels (links) for which the transmission device of the Element supports multi-link communication. Alternatively, when capability information is indicated by the Element and a link for multi-link communication has already been established, Per Link Info513 indicates information on the already established links. In this case, the set of Per Link Info513 may include the number of links already established. In this case, the link for which the communication device 102 indicates information by Per Link Info513 is established with at least one of the communication device 103 and another communication device. In this case, the link for which the communication device 103 indicates information by the Per Link Info 513 is established with at least one of the communication device 103 and another communication device. Alternatively, when the capability information is indicated by the element, the Per Link Info 513 may not be included. When the operation information is indicated by the Multi-Link Capability Element, the case where the communication device 102, which is the AP, transmits an Association Response including the element is not limited to this. In this case, the Per Link Info 513 indicates information about the link established by the exchange of this association. In this case, the Per Link Info 513 is included for the number of links established by the exchange of this association. In addition, when the communication device 103 indicates request information by transmitting an Association Request including the element, the Per Link Info 513 indicates information about the link that the communication device 103 requests to be established.In this case, Per Link Info 513 will include information for each link that the communication device 103 requests to establish.

[0111] Link ID 541 is a field that includes an identifier for identifying a link.

[0112] The Band ID 542 is a field including information indicating a frequency band to which the link indicated by the Link ID 541 belongs. This field is indicated in the same manner as the Band ID 531.

[0113] Bandwidth 543 is a field including information indicating the bandwidth in the link indicated by Link ID 541. This field is indicated in the same manner as Supported Bandwidth 532. When capability information is indicated by Multi-Link Capability Element, this field indicates the bandwidth supported in the link indicated by Link ID 541. When the communication device 102, which is an AP, indicates operation information by transmitting an Association Response including this Element, this field indicates the bandwidth used in the link indicated by Link ID 541. When the communication device 103, which is an STA, indicates request information by transmitting an Association Request including this Element, this field indicates the bandwidth requested by the communication device 103 in the link indicated by Link ID 541.

[0114] CH544 is a field including information indicating the frequency channel of the link indicated by Link ID541. This field may include the number indicating the channel as it is. Alternatively, the channel may be indicated as shown in Table 4. When capability information is indicated by a Multi-Link Capability Element, this field indicates the channel supported in the link indicated by Link ID541. When the communication device 102, which is an AP, indicates operation information by transmitting an Association Response including this Element, this field indicates the channel used in the link indicated by Link ID541. When the communication device 103, which is an STA, indicates request information by transmitting an Association Request including this Element, this field indicates the channel requested by the communication device 103 in the link indicated by Link ID541.

[0115] Moreover, Nss545 is a field including information indicating the number of streams of MIMO communication in the link indicated by Link ID541. When MIMO communication is not performed, this field may include a value of 0 or 1, or this field may be omitted. When capability information is indicated by a Multi-Link Capability Element, this field indicates the maximum number of streams supported in the link indicated by Link ID541. When the communication device 102, which is an AP, indicates operation information by transmitting an Association Response including this Element, this field indicates the number of streams used in the link indicated by Link ID541. When the communication device 103 indicates request information by transmitting an Association Request including this Element, this field indicates the number of streams requested by the communication device 103 in the link indicated by Link ID541.

[0116] By transmitting and receiving the MAC frame including the above-mentioned Multi-Link Capability Element, the communication devices 102 and 103 exchange capability information, operation information, and request information of the multi-link communication. In the present embodiment, the capability information, operation information, and request information of the multi-link communication are indicated by the same Multi-Link Capability Element, but this is not limited to the above. The capability information and the operation information or the capability information and the request information may be indicated by different Information Elements. In this case, for example, the capability information may be indicated by an Element including Common Info 511 and Per Band Info 512. Furthermore, the operation information and the request information may be indicated by an Element including Common Info 511 and Per Link Info 513. Furthermore, when the capability information is indicated by the Multi-Link Capability Element, the operation information or the request information may be indicated for some fields. Alternatively, when the operation information or the request information is indicated by the Multi-Link Capability Element, the capability information may be indicated for some fields.

[0117] 5 includes fields for Primary CH 521, Supported CH 533, and CH 544 as information indicating a frequency channel. However, this is not limiting, and it is sufficient that the Multi-Link Capability Element includes at least one of Primary CH 521, Supported CH 533, and CH 544 as information indicating a frequency channel.

[0118] Furthermore, the names of the fields, the number of fields, the order of the fields, and the like are not limited to those shown in Fig. 5. Any of the fields may be included before or after any of the fields shown in Fig. 5. Furthermore, a field included in Common Info 511 may be included in Per Band Info 512 or Per Link Info 513. The fields included in Per Band Info 512 and Per Link Info 513 may also be included in the other field or in Common Info 511. Furthermore, any of the fields shown in Fig. 5 may be omitted.

[0119] 8 and 9 show information contained in the body portion of the MAC frame of the Beacon and Probe Response transmitted by the communication device 102. The frame format of the MAC frame can be divided into a header portion and a body portion, and the MAC frame is transmitted and received in the order of the header portion and then the body portion. The header portion contains information indicating the type of the MAC frame. Specifically, for example, in the case of a Beacon, the header portion contains information indicating that the type of the MAC frame is a management frame, and further, that the subtype is Beacon. Similarly, in the case of a Probe Response, the header portion contains information indicating that the type of the MAC frame is a management frame, and that the subtype is ProbeResponse.

[0120] 8 shows information included in the body portion of the MAC frame of a Beacon transmitted by the communication device 102. The Beacon contains various pieces of information shown in the Information column as elements. These pieces of information are transmitted and received in the order shown in the Order column. Note that the Beacon does not need to contain all of the information shown in FIG. 8, and it is sufficient if it contains at least some of the information.

[0121] Of these pieces of information, the Timestamp (Order=1), the Beacon interval (Order=2), and the Capability Information (Order=3) are essential pieces of information that must be included in a Beacon. Additionally, the SSID (Order=4) and the Supported Rates and BSS Membership Selectors (Order=5) are also essential pieces of information that must be included in a Beacon.

[0122] The Timestamp contains information indicating the value of a Timing Synchronization Function (TSF) timer of the device transmitting the MAC frame.

[0123] The beacon interval includes information indicating the interval at which the beacon is transmitted by the transmitting device of the MAC frame.

[0124] The capability information includes information indicating whether the transmitting device of the MAC frame can execute a PCF (Point Coordination Function) or not, and also includes information indicating whether the transmitting device of the MAC frame needs encryption in data communication.

[0125] The SSID includes information indicating the ESS or IBSS identifier of the device transmitting the MAC frame. ESS is an abbreviation for Extended Service Set, and IBSS is an abbreviation for Independent Basic Service Set. The ESS identifier includes the ESSID, which is the identification name of the AP. Generally, the ESSID includes the SSID.

[0126] The Supported Rates and BSS Membership Selectors includes information indicating the wireless transmission rates supported by the beacon transmitting device.

[0127] Each piece of information communicated after Supported Rates and BSS Membership Selectors may or may not be included in the MAC frame.

[0128] In this embodiment, the migration destination information shown in Fig. 10 described later is arranged as an element of Order=Z communicated after the EHT Capabilities Element and the EHT Operation Element, as shown in Fig. 8. Here, the name of the element indicating the migration destination information of the multi-link communication is the migration destination link information, but is not limited to this. For example, the name may be Multi-link report element. Also, the migration destination information is arranged so as to be communicated before the Vendor Specific Element which is communicated last in the MAC frame.

[0129] The EHT Capabilities Element includes information indicating the capabilities of the MAC frame transmitting device in communication conforming to the IEEE 802.11be standard. Specifically, for example, information indicating the PHY capabilities of the MAC frame transmitting device in communication conforming to the IEEE 802.11be standard (EHT PHY Capabilities Information) is included. In addition to this, or instead, information indicating the MAC capabilities of the MAC frame transmitting device in communication conforming to the IEEE 802.11be standard (EHT MAC Capabilities Information) may be included. The MAC frame transmitting device can indicate that it is a device capable of communication conforming to the IEEE 802.11be standard by transmitting the EHT Capabilities Element. The EHT Capabilities Element may be communicated next to the element of Order=87 in the Beacon.

[0130] The EHT Operation Element includes information for controlling a communication device in communication conforming to the IEEE 802.11be standard. The operation of a communication device supporting communication conforming to the IEEE 802.11be standard and participating in a BSS conforming to the IEEE 802.11be standard is controlled by the EHT Operation Element. The EHT Operation Element may be communicated next to the EHT Capabilities Element in a Beacon.

[0131] When a beacon transmitting device transmits a beacon including destination information of multi-link communication, the beacon includes at least one of an EHT Capabilities Element and an EHT Operation Element. The destination information of multi-link communication is communicated after at least one of the EHT Capabilities Element and the EHT Operation Element, thereby ensuring compatibility. A communication device that supports only a standard earlier than the IEEE802.11ax standard cannot understand the contents of the destination information of multi-link communication even if it receives it, and therefore discards the information after the destination information. For example, if the destination information is communicated before information about communication compliant with the IEEE802.11ax standard, the receiving device may not be able to obtain information about communication compliant with the IEEE802.11ax standard of the transmitting device. By arranging the destination information of multi-link communication so that it is communicated after the EHT Capabilities and EHT Operation, the receiving device of the beacon can obtain information about communication of a standard earlier than the IEEE802.11be standard.

[0132] However, the present invention is not limited to this, and it is sufficient that the multilink transition destination information is arranged so that it is communicated at least after the SSID, Supported Rates, and BSS Membership Selectors in the beacon. By arranging the multilink transition destination information so that it is communicated after the information that is required to be included in the beacon, a receiving device that is compatible only with standards prior to the IEEE802.11ax standard can also obtain the required information included in the beacon. This ensures compatibility with legacy terminals (compatible only with standards prior to the IEEE802.11ax standard).

[0133] Similarly, the Multi-link Capability Element shown in FIG. 5 is also arranged so as to be communicated after at least one of the EHT Capabilities Element and the EHT Operation Element. This makes it possible to ensure compatibility with legacy terminals. Not limited to this, the Multi-link Capability Element may be arranged so as to be communicated after the SSID and the Supported Rates and BSS Membership Selectors. This makes it possible to ensure compatibility with legacy terminals.

[0134] 9 shows information included in the body portion of the MAC frame of a Probe Response transmitted by the communication device 103. The Probe Response includes various pieces of information shown in the Information column as elements. These pieces of information are transmitted and received in the order shown in the Order column. Note that the Probe Response does not need to include all of the information shown in FIG. 9, and it is sufficient if it includes at least some of the information.

[0135] Like a beacon, a probe response must also include a timestamp (Order=1), a beacon interval (Order=2), and capability information (Order=3). In addition to these, a probe response must also include an SSID (Order=4). Unlike a beacon, a probe response may or may not include Supported Rates and BSS Membership Selectors (Order=5).

[0136] In this embodiment, the migration destination information shown in FIG. 10 described later is arranged as an element of Order=Z communicated after the EHT Capabilities Element and the EHT Operation Element, as shown in FIG. 9. Here, the name of the element indicating the migration destination information of the multi-link communication is the migration destination link information, but is not limited to this. For example, the name may be Multi-link report element. In addition, the migration destination information is arranged so as to be communicated before the Vendor Specific Element, which is the penultimate communication in the MAC frame. By arranging the migration destination information so as to be communicated after at least one of the EHT Capabilities Element and the EHT Operation Element, compatibility with legacy terminals can be ensured.

[0137] However, the present invention is not limited to this, and the multilink migration destination information may be arranged so as to be communicated after the SSID in the probe response. This ensures compatibility with legacy terminals.

[0138] Furthermore, if the Probe Request contains information indicating a request for destination information for multi-link communication, the transmitting device of the Probe Response may communicate the destination information without communicating other elements after the SSID. By not transmitting unnecessary elements, the transmitting device of the Probe Response can reduce the number of elements to be communicated and reduce overhead.

[0139] In addition, the Multi-link Capability Element shown in FIG. 5 is also arranged so as to be communicated after at least one of the EHT Capabilities Element and the EHT Operation Element. This makes it possible to ensure compatibility with legacy terminals. Not limited to this, the Multi-link Capability Element may be arranged so as to be communicated after the SSID. This makes it possible to ensure compatibility with legacy terminals.

[0140] An example of the frame format of the destination link information element is shown in Fig. 10. The destination link information of Order=Z shown in Fig. 8 and Fig. 9 includes information as shown in Fig. 10.

[0141] The destination link information element has fields of Element ID 1101, Length 1102, Element ID Extension 1103, and Number of Links 1104. In addition to these, the destination link information element has a field of Optional Subelements 1105. The communication device 102 generates the destination link information elements shown in FIG. 10 in order starting from Element ID 1101, and transmits them to another communication device. In this case, the communication device 102 generates all fields in the frame before transmitting them. Alternatively, the communication device 102 may perform transmission in parallel with the generation of the fields. Specifically, the communication device 102 may generate Length 1102 in parallel with the transmission of the generated Element ID 1101, for example.

[0142] The Element ID 1101 includes a value indicating that this element is a destination link information element.

[0143] Length 1102 includes information specifying the number of octets of the destination link information element following Length 1102 (not including Length 1102).

[0144] The Element ID Extension 1103 includes a value for identifying different elements to which the same Element ID is assigned. In the IEEE 802.11be standard, if an Element ID Extension is not assigned to the destination link information element, this field is omitted.

[0145] Number of Links 1104 includes information indicating the number of links whose information is indicated by the destination link information element. This field is an unsigned integer field. The length of this field is 9 bits so that 0 to 511 can be identified, but it may be more or less than this. By including this field in the destination link information, the receiving device of the destination link information can identify the number of links whose information is indicated by the destination link information without analyzing the following Optional Subelements 1105. Note that since the number of links whose information is indicated can be obtained by analyzing Optional Subelements 1105, this field may be omitted.

[0146] Information about each link is indicated in Optional Subelements 1105. Optional Subelements 1105 includes Link Reports 1111 to 111m as subelements (or subfields) for the number of links whose information is indicated in the destination link information element.

[0147] The communication device 102 that transmits the destination link information transmits, as the destination link information, information on at least one of the links already established with the communication device 103, excluding the link used to transmit the destination link information. In addition to or instead of this, the communication device 102 may transmit information on a link that can be established with the communication device 103 in the future. Specifically, the communication device 102 transmits information on a wireless network that has not yet established a link with the communication device 103 but that has already been built by the communication device 102. In addition to the information on these links, the communication device 102 may also transmit information on the link used to transmit the destination link information.

[0148] The Link Reports 1111 to 111m each include fields of a Subelement ID 1121, a Length 1122, a BSSID 1123, BSSID Information 1124, and an Operating Class 1125. In addition to these fields, the Link Reports 1111 to 111m each include fields of a Channel Number 1126, a PHY Type 1127, and Optional Subelements 1128.

[0149] In this embodiment, the frame format of the Link Report uses the frame format of the Neighbor Report element defined in the IEEE 802.11 series of standards. Note that the frame format of the Link Report is not limited to that of the Neighbor Report.

[0150] Subelement ID 1121 includes information indicating that this subelement is a Link Report. When a Neighbor Report is used as a Link Report, 52 is included as an ID indicating the Neighbor Report. This field may be omitted.

[0151] Length 1122 includes information specifying the number of octets of the Link Report following Length 1122 (not including Length 1122).

[0152] BSSID 1123 includes information indicating the BSSID as identification information of the wireless network in which the link indicated in the Link Report is established. Alternatively, instead of or in addition to BSSID 1123, a Link ID field may be included as identification information of the link. Note that when indicating information of a link that has not yet been established, the Link ID field does not need to be included, or the Link ID field may include a value indicating that the link has not yet been established.

[0153] BSSID Information 1124 includes information indicating whether the wireless network indicated by BSSID 1123 is capable of communication conforming to the IEEE 802.11be standard. In addition to this, information indicating whether the wireless network indicated by BSSID 1123 is capable of communication conforming to the IEEE 802.11ax standard or the IEEE 802.11n standard may be included. Note that this field may be omitted.

[0154] The Operating Class 1125 includes information indicating a set of frequency channels in which the communication device 102 can communicate. Note that this field may be omitted.

[0155] The Channel Number 1126 includes information indicating a frequency channel used in the wireless network indicated by the BSSID 1123. When the Link Report indicates information on an already established link, the Channel Number 1126 may include information indicating the frequency channel used in that link.

[0156] The PHY Type 1127 includes information indicating the physical medium type of the MAC frame including the destination link information element.

[0157] Optional Subelements 1128 includes information about the link. Optional Subelements 1128 includes one or more Measurement Report fields. Measurement Reports 1131 to 113n are included in Optional Subelements 1128 in the number of types of information about the link. Information about the link includes information indicating the possibility of acquiring a transmission opportunity for the communication device 102 or 103 as information used for determining link switching or selection in multi-link communication. For example, information about the link includes information indicating the ratio of a period during which the frequency channel used for the link is busy or not busy in a predetermined period. Alternatively, information indicating whether a signal transmitted from another communication device or a radar has been detected in the frequency channel used for the link is included. Alternatively, information indicating the power of a signal received by the communication device 102 in the frequency channel used for the link is included. Note that the power of the signal received by the communication device 102 refers to the power of a signal transmitted from the communication device 103 and received by the communication device 102. Alternatively, the information may include information indicating a signal-to-noise ratio for a frequency channel used for the link, or information regarding the total power of noise and interference waves. Alternatively, the information may include information regarding the number of management frames and data frames received through the link or a wireless network that establishes the link. The communication device 102 may include at least one of the above information for one link as a Measurement Report in the Optional Subelements 1128.

[0158] The Measurement Reports 1131 to 113n each include fields of a Subelement ID 1141, a Length 1142, and a Measurement Token 1143. In addition to these fields, the Measurement Reports 1131 to 113n each include fields of a Measurement Report Mode 1144, a Measurement Type 1145, and a Measurement Report 1146.

[0159] Information indicating that this subelement is a Measurement Report is included in the Subelement ID 1141. Note that this field may be omitted.

[0160] Length 1142 includes information specifying the number of octets of the Measurement Report following Length 1142 (not including Length 1142).

[0161] The Measurement Token 1143 contains the same value as the Measurement Token of the Measurement Request element received from the communication device 103. The communication device 103 can request the communication device 102 to transmit destination link information by transmitting a Probe Request including the Measurement Request element to the communication device 102. Note that the communication device 102 may transmit a Measurement Request frame including the Measurement Request element instead of a Probe Request. The Measurement Request frame may be transmitted at any timing. Furthermore, when the communication device 102 transmits Measurement Reports 1131 to 113n not based on the reception of a Measurement Request element, 0 is set in the Measurement Token 1143. Note that this field may be omitted.

[0162] Measurement Type 1145 includes information indicating the type of information included in Measurement Report 1146, which will be described later. The information included in Measurement Report 1146 is the information about the above-mentioned link.

[0163] In this embodiment, as the Measurement Type, a Type indicating a type of information that is not applied to the Neighbor Report element but is applied to other elements in the standards before IEEE802.11ax may be specified. For example, Basic, CCA (Clear Channel Assessment), or RPI (Receive Power Indicator) Histogram may be specified as the Type. Alternatively, Channel Load, Noise Histogram, Beacon, or Frame may be specified as the Type.

[0164] The Measurement Report field 1146 includes information indicating frequency channel information, measurement start time, and measurement period length, regardless of the Measurement Type. It also includes information on the type indicated by Measurement Type under these conditions. Note that the Measurement Report field may be called a [Measurement Type name] Report based on the type specified in Measurement Type. For example, when the Measurement Type is Basic, the Measurement Report field is called a Basic Report.

[0165] When Measurement Type 1145 indicates Basic, Measurement Report 1146 (Basic Report) includes information indicating whether a valid MPDU from another BSS has been received. Note that MPDU is an abbreviation for Medium Access Control (MAC) Protocol Data Unit. In addition to or instead of this information, information indicating whether a sequence of short training symbols not followed by a valid SIGNAL field has been received is also included. In addition to or instead of these pieces of information, information indicating whether a large amount of power that cannot be identified as a radar wave, an OFDM preamble, or a valid MPDU has been received, or whether a radar wave has been received, is also included.

[0166] When Measurement Type 1145 indicates CCA, Measurement Report 1146 (CCA Report) includes information indicating the percentage of time that the frequency channel is busy.

[0167] When Measurement Type 1145 indicates RPI Histogram, Measurement Report 1146 includes information indicating a frequency distribution of power observed at an antenna into classes, etc. In this case, Measurement Report 1146 may be called an RPI Histogram Report.

[0168] When Measurement Type 1145 indicates Channel Load, Measurement Report 1146 (Channel Load Report) includes information indicating the percentage of time that the frequency channel is busy, etc. In addition to or instead of this, information regarding switching to a new bandwidth, etc. is also included.

[0169] When Measurement Type 1145 indicates Noise Histogram, Measurement Report 1146 (Noise Histogram Report) includes information indicating the total average power of noise and interference waves, and in addition to or instead of this, includes information indicating a frequency distribution with the total power of noise and interference waves as a class.

[0170] When Measurement Type 1145 indicates Beacon, Measurement Report 1146 (Beacon Report) includes information indicating the reception power, signal-to-noise ratio, etc. of the Beacon. Alternatively, or in addition to this, it includes information indicating the reception power, signal-to-noise ratio, etc. of the Measurement Pilot or Probe Response frame.

[0171] When Measurement Type 1145 indicates Frame, Measurement Report 1146 (Frame Report) includes information indicating the average power of the received frame, or in addition to or instead of this, includes information indicating the signal-to-noise ratio, the number of received data frames and management frames, etc.

[0172] In this embodiment, as shown in FIG. 10, all destination information is included in a single element (destination link information element). However, this is not limited to this, and the communication device 102 may independently include multiple elements as destination information. Specifically, instead of the destination link information element shown in FIG. 10, Link Reports 1111 to 111m may be included in the MAC frame as elements rather than as subelements. In this case, the Subelement ID field 1121 is replaced with an Element ID field, or an Element ID field and an Element ID Extension field. An identifier corresponding to the element is stored in these fields. Note that when a Neighbor Report is used as a Link Report, 52 is included as an ID indicating the Neighbor Report.

[0173] In the present embodiment, the Link Report includes sub-elements of Measurement Reports 1131 to 113n as information related to the link, but is not limited to this. Instead of the Measurement Report, other elements defined in the IEEE 802.11 series of standards that include information useful for the STA to determine the possibility of obtaining a transmission opportunity may be included as sub-elements.

[0174] For example, elements such as BSS Load, BSS Average Access Delay, and BSS AC Access Delay defined in standards prior to the IEEE 802.11ax standard may be included as subelements. Alternatively, or in addition, elements such as Extended BSS Load and HE BSS Load may be included as subelements. One or more of these elements may be included as subelements in one Link Report. Alternatively, at least one of the above elements may be included as a subelement in the Measurement Report subelement.

[0175] When the above elements are treated as subelements, the Element ID field of these elements is replaced with the Subelement ID field. The Subelement ID field stores an identifier for identifying the subelement in the Measurement Report or Link Report. If the Element ID Extension field exists, it is deleted. However, the Subelement ID field stores an identifier corresponding to the combination of the Element ID field value and the Element ID Extension field value.

[0176] The BSS Load includes information indicating the number of STAs contained in the target BSS, information indicating the percentage of time the medium is busy, and information indicating the total remaining medium time available through admission control.

[0177] The BSS Average Access Delay includes information indicating the average media access delay time of the AP.

[0178] The BSS AC Access Delay includes information indicating the average media access delay time of each access category, namely, AC_BE, AC_BK, AC_VI, and AV_VO.

[0179] The Extended BSS Load includes information indicating the number of VHT STAs associated with the BSS that have Multi-User (MU) beamforming capabilities, and additionally or alternatively includes information indicating the percentage of unused space in the spatial stream domain during medium busy times, and the percentage of secondary 20 MHz, 40 MHz, or 80 MHz bands in use over time.

[0180] The HE BSS Load includes information indicating the number of HE STAs associated with the target BSS, information indicating the percentage of time that the medium is busy for communication between the AP and the HE STA, etc. Note that HE STA refers to a STA that supports wireless communication compliant with the IEEE802.11ax standard. In addition to or instead of this, it also includes information indicating the unused rate in the frequency domain during the busy time of the medium, and information indicating the unused rate in the spatial stream domain during the busy time of the medium.

[0181] In addition to or instead of these elements, the Link Report or the Measurement Report may include elements that are not specified in the standards before IEEE802.11ax as subelements. In this embodiment, one of such elements is called EHT BSS Load. The EHT BSS Load includes information indicating the number of EHT STAs associated with the target BSS. The EHT BSS refers to a STA that supports wireless communication conforming to the IEEE802.11be standard. The number of EHT STAs is calculated by counting the STAs that include at least one of EHT Capabilities and EHT Operation in the management frame. In addition to or instead of this, information indicating the proportion of time that the medium is busy for communication between the AP and the EHT STA, information indicating the unused rate in the frequency domain during the busy time of the medium, and the like may be included. In addition to or instead of these information, information indicating the unused rate in the spatial stream domain during the busy time of the medium may be included.

[0182] FIG. 6 is a flowchart showing a process executed by the control unit 202 reading and executing a computer program stored in the storage unit 201 when the communication device 103 performs multi-link communication.

[0183] This flowchart starts in response to power-on of communication device 103. Alternatively, communication device 103 may start in response to an instruction to start multilink communication from a user or an application. Alternatively, communication device 103 may start in response to the amount of data to be transmitted to communication device 102 reaching or exceeding a predetermined threshold.

[0184] First, the communication device 103 acquires capability information of the other device in multi-link communication (S601). Specifically, the communication device 103 acquires the capability information of the communication device 102 by receiving a Beacon including a Multi-Link Capability Element transmitted by the communication device 102. Alternatively, the communication device 103 may perform the process of this step by receiving a Probe Response including a Multi-Link Capability Element transmitted by the communication device 102. In this case, the order of this step and S602 described later is reversed.

[0185] Next, the communication device 103 notifies the capability information of the multi-link communication of the own device (S602). Specifically, the communication device 103 notifies the capability information of the own device in the multi-link communication by transmitting a Probe Request including a Multi-Link Capability Element. If the capability information of the other device has been acquired before this step, the capability information to be notified by the own device may be determined based on the capability information of the other device. Specifically, the communication device 103 may determine the capability information to be notified in this step so as not to exceed the capability of the communication device 102. For example, consider a case where the communication device 103 supports multi-link communication at 2.4 GHz, 5 GHz, and 6 GHz, and the communication device 102 supports only 2.4 GHz and 5 GHz. In this case, the communication device 103 notifies the communication device 102 that it supports multi-link communication at 2.4 GHz and 5 GHz as capability information in this step. Note that, when the communication device 103 transmits an Association Request including request information indicating a request for multi-link communication to the communication device 102 in S603 described later, the processing in this step may be omitted.

[0186] Next, the communication device 103 transmits an Association Request including request information for multilink communication (S603). The request information transmitted in this step indicates information related to multilink communication that the communication device 103 requests to be executed. Note that in this step, the communication device 103 may transmit an Association Request that does not include request information.

[0187] The communication device 103 determines whether an Association Response has been received from the communication device 102, which is the AP (S604). If the communication device 103 has not received an Association Response, it determines No in this step and performs the process of this step again. If the communication device 103 has not determined Yes in this step even after a predetermined time has elapsed since the communication device 103 sent the Association Request in S603, it notifies the user of an error and ends the process of this flow. On the other hand, if the communication device 103 has received an Association Response, it determines Yes in this step and performs the process of S605.

[0188] The communication device 103 starts multilink communication with the communication device 102 (S605). If the Association Response received in S604 contains operation information for multilink communication, the communication device 103 starts multilink communication based on the operation information. Alternatively, if request information has been transmitted in S603 and an Association Response containing only information indicating permission has been received in S604, the communication device 103 starts multilink communication based on the request information transmitted in S603. In this embodiment, in S605, multilink communication via the multiple links established with the communication device 102 is started.

[0189] When the communication device 103 starts multi-link communication with the communication device 102, it acquires destination information of the multi-link communication from the communication device 102 (S606). Specifically, the communication device 103 receives a Beacon including the destination link information element shown in Fig. 10 from the communication device 102. The communication device 103 may receive a Beacon including the destination link information element from the communication device 102 for each Beacon Interval of the communication device 102. The Beacon received in this step may include, in addition to the destination link information element, a Multi-Link Capability Element indicating capability information in the multi-link communication of the communication device 102.

[0190] In this embodiment, the communication device 103 receives a Beacon in S606, but this is not limiting, and the communication device 103 may receive a Probe Response including a destination link information element. In this case, between S605 and S606, the communication device 103 transmits a Probe Request for requesting destination information to the communication device 102. The Probe Request transmitted by the communication device 103 may include information indicating a request for destination information. The Probe Response may not include a Multi-Link Capability Element indicating capability information in multi-link communication of the communication device 102.

[0191] The communication device 103 determines whether to change the link used in the multi-link communication with the communication device 102 (S607). Specifically, the communication device 103 determines whether the user has instructed to change the link. If the user has instructed to change the link, the communication device 103 determines Yes in this step and performs processing of S608. On the other hand, if the user has not instructed to change the link, the communication device 103 determines No in this step and performs processing of S609. In this case, the communication device 103 may display on the display unit the destination information indicated by the destination link information element acquired in S606, and display a screen that inquires the user whether to change the link. Alternatively, the communication device 103 may perform the determination in this step based on the destination link information element acquired in S606, regardless of the user instruction. For example, the communication device 103 compares the possibility of the communication device 103 obtaining a transmission opportunity in the link used for data communication with the communication device 102 with the possibility of obtaining a transmission opportunity in another link indicated by the destination link information element, and performs the judgment in this step. In this case, if the communication device 103 has a higher possibility of obtaining a transmission opportunity in another link than the currently used link, the communication device 103 judges Yes in this step. On the other hand, if the communication device 103 has a lower possibility of obtaining a transmission opportunity in another link than the currently used link, the communication device 103 judges No in this step. In this case, it is assumed that a link in which the frequency channel used for the link has a lower ratio of a period during which it is busy per a predetermined period is more likely to obtain a transmission opportunity. It is also assumed that a link with a higher signal-to-noise ratio is more likely to obtain a transmission opportunity. Alternatively, it is assumed that a link in which the power of a signal received in a frequency channel used for the link is higher is more likely to obtain a transmission opportunity. It is also assumed that a link in which the total power of noise and interference waves in a frequency channel used for the link is lower is more likely to obtain a transmission opportunity. Also, it is assumed that a link that receives fewer management frames and data frames via the wireless network that has an established link has a higher probability of obtaining a transmission opportunity.Alternatively, the communication device 103 determines "Yes" in this step if the desired throughput is not obtained in the link used for data communication with the communication device 102. Note that the throughput threshold may be set by a user or may be preset in the communication device 103.

[0192] In this embodiment, the destination information is acquired in S606, and then the determination as to whether or not to change the link is made in S607, but this is not limited thereto. The communication device 103 may first determine whether a link change instruction has been issued from the user, and then acquire the destination information. After S605, the communication device 103 makes the determination in S607 based on the user instruction, and if the determination is Yes, transmits a Probe Request to request the destination information from the communication device 102. Thereafter, the communication device 103 acquires the destination information from the communication device 102 (S606), and performs the process of S608, which will be described later, based on the acquired destination information. If the determination is No in S607, the communication device 103 performs the process of S609, which will be described later.

[0193] If the determination in S607 is Yes, the communication device 103 performs link change processing (S608). Specifically, the link change processing is to switch the link used for data communication with the communication device 102 to another link. Alternatively, without being limited to this, another link may be added as a link to be used for data communication with the communication device 102. Alternatively, the communication device 103 may establish a new link with the communication device 102 and switch or increase the link used for data communication with the communication device 102. Note that the communication device 103 may perform change processing on a link for transmitting a control frame in addition to or instead of the link used for data communication with the communication device 102.

[0194] In S608, the communication device 103 transmits a link change request to the communication device 102. Note that the communication device 102 starts data communication via the new link based on the fact that a response to the transmitted change request is returned from the communication device 103. Alternatively, when establishing a new link with the communication device 102, the communication device 103 may transmit an Association Request in S608 as in S604. In this case, the communication device 103 starts data communication via the new link based on the fact that an Association Response is received from the communication device 102.

[0195] In this case, the communication device 103 may transmit a link change request or an association request via a frequency channel used for communication of management frames with the communication device 102. Alternatively, the communication device 103 may transmit these signals via a frequency channel used for data communication.

[0196] The communication device 103 determines whether to end the multilink communication (S609). Specifically, it determines whether the user has instructed the end of the multilink communication with the communication device 102. If the user has instructed the end of the multilink communication, the communication device 103 determines Yes in this step and executes the process of S610. On the other hand, if the user has not instructed the end of the multilink communication, the communication device 103 executes the process of S606 again.

[0197] The communication device 103 disconnects the link with the communication device 102 (S610). In this case, the communication device 103 disconnects all but one of the multiple links established between the communication device 103 and the communication device 102. Specifically, the communication device 103 transmits a Disassociation frame including information that allows identification of the link to be disconnected to the communication device 102. The communication device 103 may transmit the Disassociation frame via a link that is to be maintained without being disconnected, or may transmit the Disassociation frame via any one of the links to be disconnected. Note that, although one link with the communication device 102 is maintained in this embodiment, this is not limited thereto, and all links may be disconnected in this step. After executing the process of S610, the communication device 103 ends the process of this flow.

[0198] The communication device 103 may make the determination in S609 based on whether a link for multi-link communication with the communication device 102 is maintained, rather than on a user instruction. In this case, the communication device 103 skips S610. If multiple links are maintained with the communication device 102, the communication device 103 determines No in S609. On the other hand, if multiple links are not maintained with the communication device 102, the communication device 103 determines Yes in S609. Alternatively, the communication device 103 may determine Yes in S609 if one or more links are maintained with the communication device 102, and may determine No if no link is maintained.

[0199] 6, after starting multilink communication with communication device 102, communication device 103 can acquire destination information to change the link of multilink communication with communication device 102. This allows communication device 103 to prevent a decrease in throughput in multilink communication with communication device 102 and improve communication efficiency.

[0200] FIG. 7 is a flowchart showing a process executed by the control unit 202 reading and executing a computer program stored in the storage unit 201 when the communication device 102 performs multi-link communication.

[0201] This flowchart starts in response to power-on of the communication device 102. Alternatively, the communication device 102 may start in response to an instruction to start multilink communication from a user or an application. Alternatively, the communication device 102 may start in response to the amount of data to be transmitted to the communication device 103 reaching or exceeding a predetermined threshold.

[0202] First, the communication device 102 notifies its own device of its capability information in multi-link communication (S701). Specifically, the communication device 102 notifies its own device of its capability information in multi-link communication by transmitting a Beacon including a Multi-Link Capability Element. Alternatively, the communication device 102 may perform the process of this step by transmitting a Probe Response including a Multi-Link Capability Element in response to receiving a Probe Response from the communication device 103. In this case, the order of this step and S702 described later is reversed.

[0203] Next, the communication device 102 acquires capability information of the other device in multi-link communication (S702). Specifically, the communication device 102 acquires capability information of the other device in multi-link communication by receiving a Probe Request including a Multi-Link Capability Element. Note that if a Probe Request including a Multi-Link Capability Element is not received from the other device, the process of this step may be omitted.

[0204] When the communication device 102 receives a Probe Request from the communication device 103, the communication device 102 returns a Probe Response as a response. In this case, if a Beacon including a Multi-Link Capability Element is transmitted, the Probe Response does not need to include the Element.

[0205] The communication device 102 determines whether an Association Request has been received from the communication device 103 (S703). If the communication device 102 has not received an Association Request, it determines No in this step and performs the process of this step again. If the communication device 102 has not determined Yes in this step even after a predetermined time has elapsed since transmitting a Probe Response in S702, the communication device 102 notifies the user of an error and ends the process of this flow. On the other hand, if the communication device 102 has received an Association Request, it determines Yes in this step and performs the process of S704.

[0206] Next, the communication device 102 transmits an Association Response as a response to the Association Request (S704). If the request information has not been received from the communication device 103 in S703, the communication device 102 transmits the Association Response including operation information in the multilink communication with the communication device 103. In this case, the communication device 102 determines what operation information to include in the Association Response based on the capability information of the communication device 103 in the multilink communication. The operation information that the communication device 102 transmits by including in the Association Response indicates information on the multilink communication actually performed between the communication devices 102 and 103. Note that even if the request information from the communication device 103 is included in the Association Request received in S703, the communication device 102 may transmit the Association Response including the operation information. In this case, the communication device 102 determines what operation information to include in the Association Response based on the request information from the communication device 103 in the received Association Request. Alternatively, if request information has been received from the communication apparatus 103 in S703, the communication apparatus 102 may transmit an Association Response including only information indicating whether or not multi-link communication is permitted.

[0207] The communication device 102 starts multi-link communication with the communication device 103 (S705). If operation information for multi-link communication is included in the Association Response transmitted in S704, multi-link communication based on the operation information is started. Alternatively, if request information has been received in S703 and an Association Response including only information indicating permission has been transmitted in S704, multi-link communication based on the request information received in S703 is started. In this embodiment, in S705, multi-link communication via the multiple links established with the communication device 103 is started.

[0208] When the communication device 102 starts multilink communication, it notifies destination information of the multilink communication (S706). Specifically, the communication device 102 transmits a Beacon including the destination link information element shown in Fig. 10. The communication device 102 may transmit a Beacon including the destination information at each Beacon Interval. Note that in this step, the communication device 102 may transmit the capability information transmitted in S701 in addition to the destination information.

[0209] In this embodiment, the communication device 102 transmits a Beacon including the destination information in this step, but this is not limiting, and a Probe Response including the destination information may be transmitted. In this case, the communication device 102 includes a step between S705 and S706 for determining whether a Probe Request has been received. If the communication device 102 determines that a Probe Request has been received, it performs the process of S706, and if it determines that a Probe Request has not been received, it again determines whether a Probe Request has been received.

[0210] Furthermore, the communication device 102 may transmit a probe response including different information based on the other device that transmitted the probe request. Specifically, when the communication device 102 receives a probe request transmitted from a other device (the communication device 103 in this embodiment) that has already started multilink communication, the communication device 102 transmits a probe response including destination information. In this case, the probe response does not need to include capability information for multilink communication. On the other hand, when the communication device 102 receives a probe request transmitted from a other device that has not started multilink communication, the communication device 102 transmits a probe response that does not include destination information. In this case, the probe response includes capability information for multilink communication. By changing the information to be included in the probe response depending on the transmitting device of the probe request, the amount of information to be communicated can be reduced, and overhead can be reduced.

[0211] Furthermore, the communication device 102 may transmit a probe response including different information based on whether the received probe request includes information indicating a request for destination information. When the communication device 102 receives a probe request including information indicating a request for destination information, the communication device 102 transmits a probe response including destination information. In this case, the probe response may not include multilink communication capability information. On the other hand, when the communication device 102 receives a probe request that does not include information indicating a request for destination information, the communication device 102 transmits a probe response that does not include destination information. In this case, the probe response includes multilink capability information. In this way, by changing the information included in the probe response depending on whether the probe request includes information indicating a request for destination information, the amount of information to be communicated can be reduced, and overhead can be reduced.

[0212] When the communication device 102 is notified of the transfer destination information, it determines whether to start multilink communication with another partner device (S707). The other partner device is another communication device that has not started multilink communication, and in this embodiment, is another communication device other than the communication device 103. If the communication device 102 is instructed by the user to start multilink communication with another communication device, it determines Yes in this step and performs processing of S702. On the other hand, if the communication device 102 is not instructed by the user to start multilink communication, it determines No in this step and performs processing of S708.

[0213] In addition, the communication device 102 may make the determination in S707 based on whether or not a probe request has been received from another communication device, not limited to a user instruction. In this case, the communication device 102 determines "Yes" in this step based on the fact that a probe request has been received from another communication device that has not started multilink communication, and performs the process of S703. If the communication device 102 has not received a probe request from another communication device, it determines "No" in this step, and performs the process of S708.

[0214] Alternatively, the communication device 102 may make the determination in S707 based on whether an Association Request has been received from another communication device that has not started multilink communication. In this case, the communication device 102 determines "Yes" in this step based on the receipt of an Association Request from another communication device that has not started multilink communication, and performs the process of S704. On the other hand, if the communication device 102 has not received an Association Request from another communication device, the communication device 102 determines "No" in this step, and performs the process of S708.

[0215] When the communication device 102 receives a change request or an Association Request from the communication device 103, the communication device 102 returns a change response or an Association Response as a response.

[0216] Next, the communication device 102 determines whether to change the link used in multi-link communication with the communication device 103 (S708). If the communication device 102 receives a link change request from the communication device 103, it determines Yes in this step and performs processing of S709. On the other hand, if the communication device 102 does not receive a link change request from the communication device 103, it determines No in this step and performs processing of S710. Alternatively, the communication device 102 may perform the determination of S708 based on whether or not an Association Request has been received from the communication device 103 in addition to or instead of the change request. If the communication device 103 receives an Association Request from the communication device 102, it determines Yes in this step, and if not, it determines No.

[0217] The communication device 102 performs a link change process in the multilink communication with the communication device 103 (S709). The link change process specifically refers to switching the link used for data communication in the multilink communication with the communication device 103 to another link already established with the communication device 103. In addition to or instead of this, the other link already established with the communication device 103 may be used as the link to be used for data communication with the communication device 103 in addition to the currently used link. Alternatively, the communication device 102 may newly establish a link to be used for multilink communication with the communication device 103. In this case, the communication device 102 may switch the link to be used for data communication with the communication device 103 from the current link to the newly established link, or may use the newly established link in addition to the current link.

[0218] The communication device 102 starts multi-link communication with the communication device 103 using the new link.

[0219] The communication device 102 judges whether to end the multi-link communication (S710). Specifically, the communication device 102 makes the judgment in this step based on whether a link for multi-link communication with the communication device 103 is maintained. If multiple links are maintained between the communication device 102 and the communication device 103, the communication device 102 judges No in this step and performs the process of S706. On the other hand, if multiple links are not maintained between the communication device 103, the communication device 102 judges Yes in this step and ends the process of this flow. An unmaintained link is a link whose identification information was included in the Disassociation frame transmitted from the communication device 103, or a link on which communication has not been performed for a predetermined time. Alternatively, the communication device 102 may judge Yes in S710 if one or more links are maintained between the communication device 103 and the communication device 102, and may judge No if no link is maintained.

[0220] Note that in any step after S705, the communication device 102 disconnects the link if it receives a Disassociation frame from the communication device 103. Specifically, the communication device 102 determines that the link whose identification information was included in the Disassociation frame has been disconnected, and does not perform communication using the link.

[0221] When the communication device 102 is performing multi-link communication with multiple partner devices, the communication device 102 performs the determination in S710 based on the links with all of the partner devices performing the multi-link communication. When multiple links are maintained with at least one partner device, the communication device 102 determines Yes in S710. On the other hand, when multiple links are not maintained with all of the partner devices, the communication device 102 determines No in S710.

[0222] 7, communication device 102 can notify communication device 103 of destination information after starting multilink communication with communication device 103. By notifying communication device 103 of the destination information, communication device 103 that has acquired the destination information can change the link of multilink communication with communication device 102. This allows communication device 102 to prevent a decrease in throughput in multilink communication with communication device 103, and improves communication efficiency.

[0223] In the present embodiment, the communication device 103 transmits a Probe Request in S706, but this is not limiting, and a communication device other than the communication devices 102 and 103 may transmit a Probe Request to the communication device 102. It is assumed here that the other communication devices transmitting the Probe Request have started multi-link communication with the communication device 102. In this case, the communication device 102 may transmit a Probe Response including different destination information for each communication device that transmitted the Probe Request. For example, the communication device 102 may transmit a Probe Response including destination information indicating information regarding a link established with the communication device 103 in response to a Probe Request transmitted by the communication device 103. At this time, the Probe Response transmitted to the communication device 103 does not include destination information regarding a link established with the other communication device. In this case, the communication device 102 transmits a Probe Response including destination information regarding a link established with the other communication device in response to a Probe Request transmitted by the other communication device. The probe response transmitted to the other communication device does not include destination information regarding the link established with the communication device 103.

[0224] In addition, when the communication device 102 includes destination information in the probe response, it may include only information regarding the link corresponding to the frequency channel supported by the communication device 103 based on the multi-link communication capability information received from the communication device 103.

[0225] In addition, in the present embodiment, when transmitting the destination information, the communication device 102 transmits information on all links that may become destinations, but this is not limited thereto. The communication device 102 may transmit only information on a BSS, a frequency channel, or a link that is determined to have a high possibility of the communication device 103 (STA) acquiring a transmission opportunity. For example, the communication device 102 determines that a BSS in which the proportion of time that the medium is busy is small or there is little high-priority traffic such as AC_VO or AC_VI is a BSS that is likely to have a transmission opportunity for the STA. The communication device 102 may make a similar determination regarding a frequency channel or a link. The communication device 102 includes in the BSSID field 1123 the BSSID of the BSS that is determined to have a high possibility of the STA acquiring a transmission opportunity. In this case, other fields in the Link Report may be omitted. Note that a Channel Number field 1126 may be included to indicate the frequency channel used in the BSS. When the determination is made based on a type or number of channels, only the Channel Number field 1126 may be included instead of the BSSID field 1123. Alternatively, a BSSID field 1123 indicating the ID of the BSS established by the communication device 102 in the corresponding frequency channel may be included. When determining based on the link, at least one of a Channel Number field 1126 indicating the frequency channel used in the corresponding link and a BSSID field 1123 indicating the BSS may be included. In this case, the communication device 102 selects an appropriate link as a transition destination of the link with the communication device 103, and then transmits information on the transition destination candidate link to the communication device 103. This reduces the processing load when the communication device 103 selects a transition destination link.

[0226] Note that the communication device 102 may include information about multilink communication in the MAC frame when performing multilink communication or when instructed to perform multilink communication, and may not include the information in other cases. In particular, when not performing multilink communication, the overhead of the frame can be reduced by not including destination information in the Beacon or Probe Response.

[0227] In addition, by reusing the frame format defined in standards prior to the IEEE802.11ax standard when indicating migration destination information, the development burden of software and hardware that configures or analyzes communication devices can be reduced.

[0228] In this embodiment, when the communication device 102 is performing multi-link communication, the communication device 102 includes the destination information in at least one of the Beacon and the Probe Response. On the other hand, even when the communication device 102 is performing multi-link communication, the communication device 102 does not include the destination information in the Association Response, Disassociation, Authentication, or De-Authentication. By not including the destination information in a frame used when establishing or disconnecting a link or in a frame used when authenticating a partner device, the communication device 102 can reduce frame overhead. Note that the communication device 102 may not include the destination information in at least one of the Association Response, Disassociation, Authentication, or De-Authentication.

[0229] In this embodiment, the communication device 103 selects whether to change the link currently used for data communication with the communication device 102 by acquiring information about another link via a link of multi-link communication already established with the communication device 102. In this case, changing the link refers to switching the link. Alternatively, the number of links used for data communication may be increased. Alternatively, when data communication with the communication device 102 is already performed using multiple links, the type of data transmitted via a certain link may be changed, or the ratio of transmitted data may be changed. The communication device 103 acquires information about another link from the communication device 102 via the link to be changed. Alternatively, the communication device 103 may acquire information about the link from the communication device 102 via a link different from the link to be changed. In this case, the information about the link may include information about the link used to acquire the information.

[0230] In this embodiment, when terminating multilink communication, a Disassociation frame is transmitted from communication device 103 to communication device 102, but this is not limited thereto. A Disassociation frame may be transmitted from communication device 102 to communication device 103. In this case, communication device 103 executes the process of S710 in Fig. 7 instead of S609 and S610 in Fig. 6. Also, communication device 102 executes the process of S609 and S610 in Fig. 6 instead of S710 in Fig. 7.

[0231] Also, in this embodiment, the communication devices 102 and 103 establish multiple links, start multi-link communication, and then communicate the destination information. However, this is not limited to the above, and the communication devices 102 and 103 may establish a single link and then communicate the destination information. Specifically, communication via the established single link may be started instead of multi-link communication at S605 in FIG. 6 and S705 in FIG. 7. In this case, the communication devices 102 and 103 may establish a new link and start multi-link communication at the link change at S608 in FIG. 6 and S709 in FIG. 7.

[0232] At least a part or all of the flowcharts of the communication devices 103 and 102 shown in Fig. 6 and Fig. 7 may be realized by hardware. When the flowcharts are realized by hardware, for example, a specific compiler may be used to generate a dedicated circuit on an FPGA from a computer program for realizing each step, and this may be used. FPGA is an abbreviation for Field Programmable Gate Array. Also, a gate array circuit may be formed in the same manner as an FPGA, and realized as hardware. Also, it may be realized by an ASIC (Application Specific Integrated Circuit).

[0233] The present invention can also be realized by a process in which a program for implementing 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., ASIC) that implements one or more of the functions. [Explanation of symbols]

[0234] 101 Network 102 Communication equipment (AP) 103 Communication equipment (STA) 104 First Link 105 Second Link

Claims

1. A communication device capable of performing wireless communication in accordance with the IEEE 802.11 series standard, A communication means for communicating a MAC frame including a first element including information on a second link in a second frequency channel and a second element including information indicating capability information, in a first link in a first frequency channel; establishing a first link in the first frequency channel and a second link in the second frequency channel with the other communication device by exchanging an association request frame and an association response frame with the other communication device on the first frequency channel; The MAC frame has a header portion and a body portion, The first element is disposed behind the second element in the body portion. A communication device comprising:

2. The first element is a multi-link element.

2. The communication device according to claim 1 .

3. The information regarding the second link included in the MAC frame is information regarding a second link that has not yet been established between the other communication device and the second communication device by the establishing means.

3. The communication device according to claim 1 or 2.

4. The information regarding the second link included in the MAC frame is information regarding a second link that can be established between the other communication device and the second communication device by the establishing means.

3. The communication device according to claim 1 or 2.

5. The information regarding the second link includes an identifier that identifies the second link.

5. The communication device according to claim 1, wherein the first and second inputs are connected to the first and second inputs.

6. Information regarding the second link is stored in a Link Info field regarding the second link.

6. The communication device according to claim 1, wherein the first and second inputs are connected to the first and second inputs.

7. If the communication device is capable of establishing a third link on a third frequency channel with the other communication device, the first element further includes a Link Info field regarding the third link.

7. The communication device according to claim 6.

8. The Link Info field includes a Link ID field, The Link Info field for the second link includes a Link ID field indicating an identifier of the second link.

8. The communication device according to claim 6 or 7.

9. When the establishing means establishes a first link in the first frequency channel and a second link in the second frequency channel between the other communication device and the other communication device by exchanging the Association Request frame and the Association Response frame with the other communication device on the first frequency channel, the Association Request frame and the Association Response frame each include a Multi-Link Element.

9. A communication device according to claim 1, wherein the communication device is a communication device having a plurality of communication ports.

10. When the Association Request frame and the Association Response frame exchanged with the other communication device on the first frequency channel do not include the Multi-Link Element, the establishing means does not establish a second link on the second frequency channel with the other communication device.

10. The communication device according to claim 9 .

11. The MAC frame further includes a third element, an HE Capabilities Element; The third element is disposed before the first element and after the second element in the body portion of the MAC frame.

11. The communication device according to claim 1 ,

12. The MAC frame is a MAC frame that complies with the IEEE 802.11 series standard.

12. The communication device according to claim 1 ,

13. A method for controlling a communication device capable of performing wireless communication in accordance with the IEEE 802.11 series standard, comprising: a communication step of communicating, in a first link in a first frequency channel, a MAC frame including a first element including information about a second link in a second frequency channel and a second element including information indicating capability information; an establishing step of establishing a first link in the first frequency channel and a second link in the second frequency channel with the other communication device by exchanging an association request frame and an association response frame with the other communication device on the first frequency channel; The MAC frame has a header portion and a body portion, The first element is disposed behind the second element in the body portion. A method for controlling a communication device comprising:

14. A program for causing a computer to function as the communication device control method according to claim 13.

Images