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 related to communication in wireless communication.

Background Art

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

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

[0004] Patent Document 1 discloses establishing a link when an AP and an STA communicate with each other.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In multilink communication, for example, it is possible to prioritize the use of a less congested link among multiple links for communication. To implement such control, information about other links needs to be communicated between the AP and STA. However, since multilink communication is a new technology introduced in the IEEE 802.11 series standards, compatibility must be considered when communicating information about other links, for example, using MAC frames. MAC stands for Media Access Control.

[0007] In view of the above, the present invention aims to ensure frame compatibility when communicating information about a link established on a frequency channel compliant with the IEEE 802.11 series standard with other communication devices. [Means for solving the problem]

[0008] To achieve the above objective, the communication device of the present invention provides a first link in a first frequency channel that includes information about a second link in a second frequency channel. information and a second information including Capability Information information and prescribed The system includes communication means for communicating MAC frames, and establishment means for establishing a first link on the first frequency channel and a second link on the second frequency channel with other communication devices by exchanging Association Request frames and Association Response frames with other communication devices on the first frequency channel, prescribed A MAC frame has a header portion and a body portion, and in the body portion the first information is the second of the above information It will be placed later. Furthermore, in order to achieve the above objective, the communication device of the present invention provides a first frequency channel The communication means for communicating a predetermined MAC frame and the first frequency of other communication devices Through association in the channel, the first communication device A first link in the frequency channel and a second different from the first frequency channel It has establishing means for establishing a second link in the frequency channel, and the predetermined MAC The frame has a header portion and a body portion, and in the body portion, the second frequency The first information, which includes information about the second link in several channels, is from Capabilit. It is characterized by being placed after the second piece of information which contains information indicating y Information. Let's assume that. [Effects of the Invention]

[0009] According to the present invention, frame compatibility can be ensured by appropriately communicating information regarding links established on frequency channels compliant with the IEEE 802.11 series standards with other communication devices. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows the network configuration to which the communication device 102 belongs. [Figure 2] This diagram shows the hardware configuration of the communication device 102. [Figure 3] This diagram shows the functional configuration of the communication device 102. [Figure 4] This sequence diagram shows an example of the process performed when communication devices 102 and 103 establish a multilink communication link. [Figure 5] This figure shows an example of the frame format for the Multi-Link Capability Element. [Figure 6] This flowchart shows the processes that the communication device 103 performs when performing multilink communication. [Figure 7] This flowchart shows the processes that the communication device 102 performs when performing multilink communication. [Figure 8] This diagram shows the information contained in a beacon. [Figure 9] This diagram shows the information contained in the Probe Response. [Figure 10] This figure shows an example of the frame format for a destination link information element (Information Element). [Modes for carrying out the invention]

[0011] Hereinafter, embodiments 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 the network in which the communication device 102 according to this embodiment participates. The communication device 102 is an access point (AP) having a role of constructing the network 101. Note that the network 101 is a wireless network. In this embodiment, when the communication device 102 constructs a plurality of networks, the BSSIDs of each network are all different. Note that BSSID is an abbreviation for Basic Service Set Identifier and is an identifier for identifying a network. Also, it is assumed that the SSIDs indicated by the communication device 102 in each network are all common. Alternatively, the communication device 102 may use different SSIDs for each network. Note that SSID is an abbreviation for Service Set Identifier and is an identifier for identifying an access point.

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

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

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

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

[0017] Communication devices 102 and 103 can perform communication in three modes as multilink communication. One is Asynchronous Mode (Async Mode), in which communication via each link in multilink communication is performed asynchronously. Specifically, communication via the first link and communication via the second link are performed at independent timings. Therefore, both the first and second links can perform communication at timings independent of when the other link is performing communication. In this case, if the channel spacing between the frequency channels (channels) used by each link is narrow, communication on one link will affect communication on the other link. Specifically, if the frequency channels of the links are close, the other link will detect communication on one link using carrier sense, so communication on the other link cannot be performed while communication is taking place on one link. Therefore, in Async Mode, the channel spacing between links is widened. Another mode is Synchronous Mode (Sync Mode), in which communication via multiple links is performed synchronously. Specifically, the first and second links begin communication at the same time. In this case, since communication via each link starts simultaneously, the other link does not carrier sense the communication on the other link, so the channel spacing between the channels used by each link can be narrow. Another mode is Semi-Asynchronous Mode (Semi-Async Mode). In this mode, when data communication is performed via one link, if the frequency channel of the other link is free, communication via both links is performed synchronously. For example, if the backoff counter of the first link becomes 0 and the frequency channel of the second link is free, communication via the first and second links will start at the same time. In this case, the backoff counter of the second link does not need to be 0.Furthermore, if the backoff counter of the first link becomes 0 and the frequency channel of the second link is not available, communication will only be initiated via the first link, and communication via the second link will not be initiated. In this mode, when communication is performed in parallel via multiple links, communication via each link is initiated simultaneously, so the spacing between the channels used for each link may be narrow. Communication devices 102 and 103 may select the mode to be used for multilink communication based on the channel spacing of the established multiple links.

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

[0019] When performing multilink communication, communication devices 102 and 103 divide a single piece of data and transmit it to the other device via multiple links. Alternatively, communication devices 102 and 103 may transmit the same data via each of the multiple links, so that communication via one link serves as a backup for communication via the other link. Specifically, suppose communication device 102 transmits the same data to 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 communication via the first link, for example, communication device 103 can receive the data transmitted from communication device 102 because the same data is being transmitted via the second link. Alternatively, communication devices 102 and 103 may use different links depending on the type of frame or data being communicated. For example, communication device 102 may transmit management frames via the first link and data frames containing 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 broadcast network information. Probe Request frames are frames that request network information, and Probe Response frames are the responses that provide network information. Association Request frames are frames that request a connection, and Association Response frames are the responses that indicate connection permission or errors. Disassociation frames are frames that disconnect a connection.An Authentication frame is a frame used to authenticate the other device, while a De-Authentication frame is a frame used to interrupt the authentication of the other device and disconnect the connection. An Action frame is a frame used to perform additional functions other than those described above. Communication devices 102 and 103 send and receive management frames compliant with the IEEE 802.11 series standard. Alternatively, when communication device 102 transmits data related to an captured image, for example, metadata such as the date, parameters at the time of capture (aperture value and shutter speed), and location information may be transmitted via the first link, and pixel information may be transmitted via the second link.

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

[0021] In this embodiment, when communication device 102 is performing multilink communication with communication device 103, it can transmit information about the second link 105 to communication device 103 via the first link 104. Information about the second link 105 includes, for example, the frequency channel used by the second link 105 and information indicating whether the frequency channel is busy (occupied). Upon receiving information about the second link 105, communication device 103 can use the received information to determine whether to switch the link used for data communication with communication device 102 from the first link 104 to the second link 105. In this way, communication device 103 can switch to a more appropriate link for data communication by receiving information about other links established with communication device 102. In this embodiment, such information about the second link 105 is called the destination information for multilink communication. Details of the destination information will be explained in Figure 10 below.

[0022] Furthermore, communication device 102 may transmit information about links it can establish with communication device 103, in addition to or instead of information about links already established with communication device 103. Information about links that can be established with communication device 103 is, for example, information indicating a frequency channel where communication device 102 has already established a wireless network but has not yet established a link with communication device 103. Alternatively, or in addition to this, it may be information indicating whether the frequency channel is busy. In this embodiment, in addition to or instead of the information about the second link 105, this information may be called multilink communication transition destination information. Details of this information will be explained in Figure 10 below. By receiving such information, communication device 103 can establish a new link with 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 establishing a new link to switch to when switching links, the power saving of communication devices 102 and 103 can be improved.

[0023] Although communication devices 102 and 103 are said to be compliant with the IEEE 802.11be standard, they may also be compliant with at least one of the legacy standards that precede the IEEE 802.11be standard. Legacy standards refer to the IEEE 802.11a / b / g / n / ac / ax standards. In this embodiment, at least one of the IEEE 802.11a / b / g / n / ac / ax / be standards is referred to as the IEEE 802.11 series standard. In addition to the IEEE 802.11 series standard, they may also be compliant with other communication standards such as Bluetooth®, NFC, UWB, Zigbee, and MBOA. UWB stands for Ultra Wide Band, MBOA stands for Multi Band OFDM Alliance, OFDM stands for Orthogonal Frequency Division Multiplexing, and NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, Winet, and others. It may also support wired communication standards such as wired LAN.

[0024] Specific examples of communication device 102 include, but are not limited to, wireless LAN routers and PCs. Communication device 102 can be any communication device capable of performing multilink communication with other communication devices. Furthermore, communication device 102 may also be an information processing device such as a wireless chip capable of performing wireless communication compliant with the IEEE 802.11be standard. Similarly, specific examples of communication device 103 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, and video cameras. Communication device 103 can be any communication device capable of performing multilink communication with other communication devices. Furthermore, communication device 103 may also be an information processing device such as a wireless chip capable of performing wireless communication compliant with the IEEE 802.11be standard. Also, while the network in Figure 1 consists of one AP and one STA, the number of APs and STAs is not limited to this. Note that the information processing device such as a wireless chip has an antenna for transmitting the generated signals.

[0025] In this embodiment, communication device 102 is an AP and communication device 103 is an STA, but this is not limited to this configuration; both communication devices 102 and 103 may be STAs. In this case, communication device 102 is an STA, but it operates as a device that has the role of building a wireless network to establish a link with communication device 103.

[0026] Figure 2 shows the 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 memory unit 201 is composed of one or more memories such as ROM and RAM, and stores various information such as computer programs for performing various operations described later, and communication parameters for wireless communication. ROM stands for Read Only Memory, and RAM stands for Random Access Memory. In addition to memories such as ROM and RAM, the memory unit 201 may also use 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. Furthermore, the memory unit 201 may have multiple memories.

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

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

[0030] The input unit 204 receives various operations from the user. The output unit 205 provides various outputs to the user via a monitor screen or speaker. Here, the output from the output unit 205 may be a display on the monitor screen, audio output via a speaker, vibration output, etc. The input unit 204 and the output unit 205 may be implemented in a single module, such as a touch panel. The input unit 204 and the output unit 205 may be integrated with the communication device 102, or they may be separate units.

[0031] The communication unit 206 controls wireless communication compliant with the IEEE 802.11be standard. In addition to the IEEE 802.11be standard, the communication unit 206 may also control wireless communication compliant with other IEEE 802.11 series standards, or 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, etc., in addition to the IEEE 802.11be standard, it may also control wireless communication compliant with these communication standards. Furthermore, if the communication device 102 can perform wireless communication compliant with multiple communication standards, it may be configured to have separate communication units and antennas 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 separately from the communication unit 206, or it may be configured as a single module together with the communication unit 206.

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

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

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

[0035] The capability information generation unit 301 is a block that generates capability information related to multilink communication of the communication device 102. The communication device 102 generates capability information to notify other communication devices of its own capabilities regarding multilink communication. The capability information related to multilink communication will be explained in Figure 5 below. Regarding capability information, the communication device may notify other communication devices of its own capability information, or it may simply receive capability information of the other device from other communication devices.

[0036] The operation information determination unit 302 is a block that determines operation information regarding multilink communication with the other device based on the capability information regarding multilink communication of its own device and the other device. Operation information regarding multilink communication refers to the frequency channel and bandwidth used for communication performed as multilink communication between communication devices 102 and 103. Details of the operation information regarding multilink communication will be explained in Figure 5 below. The determined operation information may or may not be notified to the other device.

[0037] The connection processing unit 304 is a block that performs processing to allow communication device 103, which is an STA, to join the network 101 established by communication device 102. Specifically, the connection processing unit 304 causes communication device 102 to send an Association Response frame as a response to the Association Request, which is a connection request received from communication device 103. Communication device 102 has a connection processing unit 304 corresponding to each of the multiple links it establishes.

[0038] The MAC frame generation unit 305 is a block that generates MAC frames containing information indicating capability information related to multilink communication generated by the capability information generation unit 301 and operational information related to multilink communication determined by the operational information determination unit 302. It also generates MAC frames containing information indicating migration destination information related to multilink communication generated by the migration destination information generation unit 307, which will be described later. The MAC frames generated by the MAC frame generation unit 305 are transmitted in at least one of the wireless frames of Beacon, Probe Response, and Association Response. In addition to or instead of this, the generated MAC frames are transmitted in the Reassociation Response. The capability information and operational information contained in the MAC frames generated by the MAC frame generation unit 305 are indicated by the Elements shown in Figure 5, which will be described later. The migration destination information contained in the MAC frames generated by the MAC frame generation unit 305 is indicated by the Elements shown in Figure 10, which will be described later.

[0039] The data transmission / reception unit 306 is a block that transmits and receives data frames in multilink communication based on the operational information related to multilink communication determined by the operational information determination unit 302. The data transmission / reception unit 306 may also transmit wireless frames including MAC frames generated by the MAC frame generation unit 305 and receive wireless frames from the other device.

[0040] The destination information generation unit 307 is a block that generates information about other links in multilink communication to be transmitted by the communication device 102 to the communication device 103. The communication device 102 generates information about links that are different from the link that it has established with the communication device 103 and that it uses to transmit the information. Information about other links will be explained in Figure 10 below. In addition, information about links that can be established with the communication device 103 may also be generated as information about other links. Information about links that can be established with the communication device 103 refers to links that have not yet been used to establish a link with the communication device 103 but can be established via the wireless network that the communication device 102 has constructed. Furthermore, in addition to information about other links, information about the link used to transmit the information may also be generated as information to be transmitted to the communication device 103.

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

[0042] The communication device 103 has a request information determination unit 302 instead of an operation information determination unit 302. This unit is a block that determines request information regarding multilink communication with the other device based on the capability information regarding multilink communication of its own device and the other device. Request information regarding multilink communication refers to the frequency channel and bandwidth to be used in the communication to be executed as multilink communication between communication devices 102 and 103. Details of the request information regarding multilink communication will be explained in Figure 5 below. The communication device 103 may or may not notify the other device of the determined request information.

[0043] The connection processing unit 304 is a block that processes the connection of the communication device 103 to join the network 101 established by the communication device 102, which is an AP. Specifically, the connection processing unit 304 causes the communication device 103 to send 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] Furthermore, the MAC frame generation unit 305 is a block that generates MAC frames containing information indicating capability information related to multilink communication generated by the capability information generation unit 301 and request information related to multilink communication determined by the request information determination unit 302. The MAC frames generated by the MAC frame generation unit 305 are transmitted in at least one of the wireless frames of Probe Request, Association Request, and Reassociation Request. The capability information and request information included in the MAC frames generated by the MAC frame generation unit 305 are indicated by the Elements shown in Figure 5, which will be described later.

[0045] Furthermore, the communication device 103 does not necessarily have a destination information generation unit 307.

[0046] Figure 4 shows a sequence diagram illustrating an example of the process performed when communication device 102 and communication device 103 establish a multilink communication link.

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

[0048] The processing of this sequence begins when the power to each of the communication devices 102 and 103 is turned on. Alternatively, at least one of the communication devices 102 and 103 may begin when instructed by a user or application to start multilink communication. Alternatively, at least one of the communication devices 102 and 103 may begin when the amount of data to be communicated with the other device exceeds a predetermined threshold.

[0049] First, the communication device 102 transmits a Beacon containing its own network information on the first frequency channel, thereby notifying surrounding STAs of the network information (S401). Specifically, the network information includes the transmission interval at which the communication device 102 transmits beacons and the SSID of the communication device 102. In addition, the communication device 102 may also notify information about its multilink communication capabilities by including the Multi-Link Capability Element shown in Figure 5 (described later) as part of the network information in the Beacon.

[0050] When communication device 103 receives a Beacon from communication device 102 being transmitted on the first frequency channel, it sends a Probe Request on the first frequency channel to query the network information of communication device 102 (S402). The Probe Request includes the SSID of communication device 103. In addition, communication device 103 may also include the Multi-Link Capability Element shown in Figure 5 below in the Probe Request to notify communication device 103 of its multi-link communication capability information.

[0051] When communication device 102 receives a Probe Request, it sends a ProbeResponse to communication device 103 on the first frequency channel as a response (S403). If communication device 102 does not include the Multi-Link Capability Element shown in Figure 5 in the Beacon, it includes the Element in the Probe Response and sends it. Alternatively, communication device 102 may include only some of the information contained in the Multi-Link Capability Element shown in Figure 5 in the Beacon, and include the remaining information or all of the information in the Probe Response.

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

[0053] Next, communication device 103 transmits an Association Request, which is a connection request, to communication device 102 on the first frequency channel. In this case, communication device 103 may notify communication device 103 of its multi-link communication capability information by including the Multi-Link Capability Element shown in Figure 5 in the Association Request. Communication device 103 may also determine the capability information to transmit in S404 based on the multi-link communication capability information of communication device 102 obtained in at least one of S401 or S403. For example, even if communication device 103 can combine links in the 2.4GHz band and the 5GHz band in multi-link communication, communication device 102 may only support multiple links in the 2.4GHz band. In this case, communication device 103 may transmit only capability information regarding the establishment of multiple links in the 2.4GHz band as the capability information to transmit in this step. Furthermore, in this embodiment, the communication device 103 transmits capability information regarding its own multilink communication in S402, but it is not limited to this, and capability information may not be transmitted in S402, and may only be transmitted in this step. Alternatively, the communication device 103 may include the Multi-Link CapabilityElement shown in Figure 5 in the Association Request to transmit request information required when performing multilink communication, rather than capability information. The request information requested by the communication device 103 may be shown by the Multi-Link Capability Element in Figure 5, or by another Element. Details of the request information will be explained in Figure 5 below.

[0054] When communication device 102 receives an Association Request, it sends an Association Response to communication device 103 on the first frequency channel as a response (S405). The Association Response sent here includes a Multi-Link Capability Element that indicates the operational information for multilink communication with communication device 103, as determined by communication device 102. Note that the operational information may be indicated by an Element other than the Multi-Link Capability Element. Also, if communication device 103, which is the STA, sent an Association Request in S404 that included the operational information it requested, communication device 102 may send an Association Response that only includes whether or not it can respond to the request.

[0055] If communication device 103 is capable of performing multilink communication based on the operational information included in the Association Response, communication devices 102 and 103 establish a link via the first frequency channel and begin data communication (S406). In this case, if the operational information transmitted by communication device 102 includes operational information for a link via the second frequency channel, communication devices 102 and 103 also establish a link via the second frequency channel and begin data communication (S407).

[0056] Similarly, if communication device 102 grants permission in S405 to the request information requested by communication device 103 in S404, the processing in S406 is performed. Also, if the request information transmitted by communication device 103 in S404 includes request information regarding a link via a second frequency channel, the processing in S407 is performed.

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

[0058] Furthermore, although this embodiment shows a case where multilink communication is started from a state where a link has not yet been established between communication devices 102 and 103, it is not limited to this. Communication devices 102 and 103 may start link communication by establishing a new link in addition to the links that have already been established. In this case, if communication device 103, which is an STA, has already acquired the capability information for multilink communication of communication device 102, which is an AP, it may start from processing S404. Alternatively, if communication device 102 has already acquired the capability information for multilink communication of communication device 103, it may send a signal to communication device 103 to send an Association Request, thereby enabling it to start from processing S404. Alternatively, communication devices 102 and 103 may establish a new link in addition to the multiple links that have already been established. In this case as well, the sequence in Figure 4 may start from S404.

[0059] Furthermore, communication device 102 transmits Beacons at predetermined intervals. Based on the destination information contained in the Beacons transmitted at predetermined intervals, communication device 103 can determine whether to switch the link used for data communication with communication device 102 from the currently used link to another link. In addition, communication device 102 transmits a Probe Response in response to a Probe Request transmitted from communication device 103. Communication device 103 may transmit a Probe Request to communication device 102 not only to inquire about the network information of communication device 102, but also for the purpose of obtaining destination information.

[0060] Figure 5 shows an example of the frame format of a Multi-Link Capability Element. In this embodiment, the element shown in Figure 5 is named "Multi-Link Capability Element," but it is not limited to this and may be named by other names, such as "Multi-Link Element."

[0061] Communication devices 102 and 103 can use the Multi-Link Capability Element shown in Figure 5 to notify the other device of capability information indicating their own capabilities in multilink communication. Furthermore, communication device 102 can use the Multi-Link Capability Element shown in Figure 5 to notify the other device of operational information for multilink communication, in addition to or instead of capability information. Similarly, communication device 103 can use the Multi-Link Capability Element shown in Figure 5 to notify the other device of request information for multilink communication, in addition to or instead of capability information.

[0062] The Multi-Link Capability Element shown in Figure 5 consists of an Element ID 501, a Length 502, and ML (Multi-Link) Capabilities 503. Element ID 501 is an identifier for identifying an Information Element, and in this embodiment, it includes an identifier indicating a Multi-Link Capability Element. Length 502 is a field indicating the data length of the Element, and in this embodiment, it includes information indicating the data length of ML Capabilities 503. 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 ML Capabilities 503 will be described later.

[0063] Furthermore, communication devices 102 and 103 generate the Multi-Link Capability Elements shown in Figure 5, starting with Element ID 501, and transmit them to other communication devices. In this case, communication devices 102 and 103 generate all fields within the frame before transmitting. Specifically, 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, communication devices 102 and 103 may transmit fields in parallel with their generation. Specifically, communication devices 102 and 103 may, for example, transmit Length 502 in parallel with the transmission of the generated Element ID 501.

[0064] The AP (Access Point) communication device 102 transmits wireless frames such as Beacon and Probe Response with a MAC frame containing the Multi-Link Capability Element attached. In addition to these wireless frames, the communication device 102 can also attach a MAC frame containing this Element to wireless frames such as Association Response and Reassociation Response. The STA (Stand-Assisted Device) communication device 103 transmits wireless frames such as Probe Request and Association Request with a MAC frame containing the Multi-Link Capability Element attached. In addition to these wireless frames, the communication device 103 can also attach a MAC frame containing this Element to Reassociation Request.

[0065] ML Capabilities503 consists of Common Info511, Per Band Info512, and Per Link Info513. Common Info511 is a field that shows information common to all frequency bands and links. Per Band Info512 is a field that shows information common to all links included in a particular frequency band, and the information is shown for each frequency band. PerLink Info513 is a field that shows information for each link.

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

[0067] Primary CH521 is a field containing information indicating the frequency channel used for sending and receiving management frames related to multilink communication. Primary CH refers to the frequency channel used when sending and receiving management frames when connecting or disconnecting links in multilink communication. Specifically, it contains information indicating the frequency channel used for sending and receiving Beacons and other devices that include Multi-Link Capability Elements. Communication device 102, which is an AP, includes information indicating the frequency channel used when transmitting a Beacon that includes a Multi-Link Capability Element. Communication device 103, which is an STA, includes information indicating the frequency channel on which it receives a Beacon that includes a Multi-Link Capability Element (i.e., sends a Probe Request that includes the Element). In this embodiment, it includes information indicating the first frequency channel on which Beacons and Probe Requests / Responses were sent and received in Figure 4. If the frequency channel used for sending and receiving management frames changes after communication devices 102 and 103 have started multilink communication, Primary CH521 will contain information on the frequency channel corresponding to the change. Furthermore, Primary CH521 includes information indicating the frequency channel on which management frames are transmitted and received, regardless of whether the element is displaying capability information, operational information, or request information.

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

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

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

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

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

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

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

[0075] Furthermore, when operational information is indicated by the Multi-Link Capability Element, this field may indicate whether or not to execute Semi-Async Mode for multilink communication. For example, when communication device 102 sends an Association Response, this field indicates whether or not to execute Semi-Async Mode in the communication of the Link established by this association exchange. For example, if this field contains 0, it indicates that multilink communication in Semi-Async Mode will not be executed. For example, if this field contains 1, it indicates that multilink communication in Semi-Async Mode will be executed.

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

[0077] Furthermore, if the choice of Sync Mode, Async Mode, or Semi-Async Mode to be used when communication devices 102 and 103 perform multilink communication is pre-configured, 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 can support in multilink communication. The maximum number of links refers to the maximum number of links that the Element's transmitting device can establish with a single peer device. For example, if this field contains the value 3, it indicates that the Element's transmitting device can establish up to 3 links with a single peer device. In this case, the Element's transmitting device may maintain 3 links with one peer device while simultaneously maintaining multiple additional links with another peer device. Alternatively, the maximum number of links may indicate the maximum number of links that the Element's transmitting device can establish in multilink communication, regardless of the peer device. In this case, for example, if this field contains the value 3 and the Element's transmitting device has established 3 links with a peer device, the transmitting device cannot establish any more links, regardless of the peer device. The AP (Access Point) communication device 102 and the STA (Stand-Assistant) communication device 103 each include information in this field indicating the maximum number of links that they can simultaneously maintain in multilink communication.

[0079] Furthermore, when operational information is indicated by the Multi-Link Capability Element, this field may also include the number of links actually established in multilink communication. For example, when communication device 102, which is an AP, sends an Association Response that includes this Element, this field indicates the number of links established through the exchange of this association. Alternatively, it may include the maximum number of links that can be established in multilink communication with communication device 103. In this case, Total Max Link Number 524 will include a value less than or equal to the smaller of the maximum number of links that the local device can establish in multilink communication and the maximum number of links that the other device can establish.

[0080] Alternatively, when request information is indicated by the Multi-Link Capability Element, this field may include the number of links to be established in multilink communication. For example, when communication device 103, which is an STA, sends 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 multilink communication with communication device 102. Note that when operational information or request information is indicated by the Multi-Link Capability Element, this field may be omitted.

[0081] Band Combination Info 525 is a field containing capability information indicating the frequency bands that the communication device 102 or 103, which transmits the Element, supports during multilink communication. Table 1 shows an example of the information indicated by each bit in this field. In Table 1, each bit indicates which frequency band or combination of frequency bands is supported. In this embodiment, if the bit contains 0, it indicates that multilink communication in the manner indicated by that bit is not supported, and if it contains 1, it indicates that multilink communication in the manner indicated by that bit is supported. For example, if the Band Combination Info 525 transmitted by communication device 102 contains 1 in bit 0, it indicates that communication device 102 supports multilink communication on different channels in the 2.4GHz band. Also, for example, if the value of Band Combination Info 525 is 0000111000, it indicates that communication device 102 supports multilink communication using multiple links with different frequency bands. In this case, it indicates that communication device 102 does not support multilink communication using multiple links with the same frequency band. Furthermore, setting all bits of Band Combination Info525 to 0 may indicate that the transmitter of the Multi-Link Capability Element does not support Multi-Link communication. Alternatively, it may indicate that the transmitter of the Element is currently unable to perform multi-link communication. Note that communication devices 102 and 103 may support different frequency bands for single-link communication and multi-link communication. For example, communication devices 102 and 103 may support all of 2.4GHz, 5GHz, and 6GHz for single-link communication, but only support 5GHz and 6GHz for multi-link communication. Note that the correspondence between each bit of Band Combination Info525 and its contents is not limited to that shown in Table 1.Furthermore, increasing the number of bits in Band Combination Info525 may allow for the indication of more frequency band combinations, or the possibility of establishing multiple links in different frequency bands.

[0082] [Table 1]

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

[0084] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may indicate the frequency band to be used in multilink communication. For example, when a communication device 103, which is an STA, sends an Association Request including this Element, this field indicates the frequency band to which the communication device 103 requests the communication device 102 to perform multilink communication. Even when the Element indicates operational information or request information, this field may also include capability information indicating the frequency bands that the transmitting device of the Element supports in multilink communication.

[0085] Per Band Info Number 526 is a field that contains information indicating the number of Per Band Info entries included in Per Band Info 512, which is described below. Per Band Info 512 contains a set of Per Band Info entries for each frequency band supported in multi-link communication by the communication device 102 or 103 that transmits the Multi-Link Capability Element. Specifically, it contains information indicating the same number as the number of frequency bands shown in Band Combination Info 525. However, this does not apply if information for multiple frequency bands is shown in a common Per Band Info in Per Band Info 512, which is described below. Also, if Per Band Info 512 is omitted, this field is also omitted.

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

[0087] Device Type 529 is a field containing capability information indicating what type of device the communication device 102 or 103 transmitting the Element is in multilink communication. Specifically, it contains information indicating which of the following four types the transmitting device of the Element is: A first type of device is one that can simultaneously transmit data over one link and receive data over other links in multilink communication. A second type of device is one that, when transmitting data over one link, can simultaneously transmit data over other links only. A third type of device is one that, when receiving data over one link, can simultaneously receive data over other links only. A fourth type of device is one that can maintain multiple links simultaneously, but when communicating data over one link, cannot simultaneously communicate data over other links.

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

[0089] Alternatively, when request information is indicated by the Multi-Link Capability Element, Device Type 529 may indicate which type of device the device requests to operate as in multilink communication. For example, if communication device 103, which is an STA, sends an Association Request including this Element, this field indicates which type of device communication device 103 wants to operate as in multilink communication. For example, if this field contains information indicating a second type, it indicates that communication device 103 requests to operate as a second type of device in multilink communication with communication device 102.

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

[0091] Band ID 531 is a field containing information that identifies the frequency band. Table 2 shows an example of the correspondence between the values ​​contained in Band ID 531 and the meaning they represent. For example, if Band ID 531 contains the value 0, then Per Band Info 512, which includes this Band ID 531, indicates information common to the links in multilink communication in the 2.4GHz band. Note that the correspondence between the values ​​contained in Band ID 531 and the meaning they represent is not limited to this example. Furthermore, increasing the number of bits in Band ID 531 may allow for the representation of more frequency bands.

[0092] [Table 2]

[0093] Supported Bandwidth532 is a field containing capability information indicating the bandwidth supported by the communication device 102 or 103 that transmitted the Element in the frequency band indicated by Band ID531. The bandwidth indicated here is information indicating the bandwidth supported per link when the Element's transmitter performs multilink communication in the frequency band indicated by Band ID531. Table 3 shows an example of the correspondence between the values ​​included in Supported Bandwidth532 and what those values ​​indicate. For example, if Supported Bandwidth532 contains the value 0, it indicates that the Element's transmitter supports a bandwidth of 20 MHz in the frequency band indicated by Band ID531. If the value of Supported Bandwidth532 is 1 or greater, the Element's transmitter can support any bandwidth less than or equal to that value when establishing a multilink communication link. For example, if the value of Supported Bandwidth532 is 2, the transmitter supports 20 MHz, 40 MHz, and 80 MHz as link bandwidths. Note that communication devices 102 and 103 may support different bandwidths for single-link communication and multi-link communication. For example, communication devices 102 and 103 may support a bandwidth of 80 MHz at 5 GHz for single-link communication, but support a bandwidth of 20 MHz for multi-link communication. Note that the correspondence between the values ​​included in Supported Bandwidth532 and the content they represent is not limited to this. Furthermore, increasing the number of bits in Supported Bandwidth532 may allow for the representation of a wider range of frequency bands.

[0094] [Table 3]

[0095] Furthermore, when operational information is indicated by the Multi-Link Capability Element, this field may indicate the bandwidth actually used in multi-link communication. For example, when communication device 102, which is an AP, sends an Association Response that includes this Element, this field includes information indicating the bandwidth of the link established by the exchange of this association. For example, when communication devices 102 and 103 establish a link with a bandwidth of 40 MHz at 2.4 GHz, the value of Supported Bandwidth532 will be 1.

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

[0097] Supported CH533 is a field containing capability information indicating the channels supported by the communication device 102 or 103 that transmitted the Element in the frequency band indicated by Band ID 531. The channels indicated here are those on which the Element's transmitting device supports multilink communication in the frequency band indicated by Band ID 531. Table 4 shows an example of the correspondence between each bit of Supported CH533 and the channel indicated by that bit. For example, if a bit contains the value 0, it indicates that the Element's transmitting device does not support the channel indicated by that bit, and if it contains the value 1, it indicates that the channel indicated by that bit is supported. For example, if Supported CH533 contains the value 0000010010100, it indicates that the transmitting device in this field supports multilink communication on channels 3, 5, and 8. Note that the channels supported by communication devices 102 and 103 in single-link communication and the channels supported in multilink communication may differ. For example, communication devices 102 and 103 may support all channels 1 through 13 in single-link communication, but may support only some channels, such as channels 1 and 5, in multi-link communication. Note that the correspondence between each bit of SupportedCH533 and its content is not limited to what is shown in Table 4. Furthermore, increasing the number of bits in SupportedCH533 may allow for the representation of more channels. For example, Table 4 only shows channels at 2.4GHz as an example, but by increasing the number of bits, channels at 5GHz and 6GHz may be represented from bit 13 onwards. Alternatively, if Band ID 531 contains information indicating 5GHz, the channels at 5GHz may be shown in ascending order starting from bit 0. Similarly, if Band ID 531 includes 6GHz, the channels at 6GHz may be shown in ascending order starting from bit 0.

[0098] [Table 4]

[0099] Furthermore, when operational information is indicated by the Multi-Link Capability Element, this field may indicate the channel actually used in multi-link communication. For example, when communication device 102, which is an AP, sends an Association Response that includes this Element, this field includes information indicating the channel of the link established by the exchange of this association. For example, when communication devices 102 and 103 establish a link between channel 1 and channel 4 at 2.4GHz, the value of Supported CH533 will be 0000000001001.

[0100] Alternatively, when request information is indicated by a Multi-Link Capability Element, this field may indicate the channel to be requested for use in multilink communication. For example, when a communication device 103, which is an STA, sends an Association Request including this Element, this field indicates the channel on which the communication device 103 requests the establishment of a link from the communication device 102. Even when the Element indicates operational information or request information, this field may also include capability information indicating the channels supported by the transmitting device of the Element in multilink communication.

[0101] The Async Mode CH Distance 534 field contains capability information indicating the channel spacing required in Async Mode by the transmitting device that transmitted the Element in the frequency band indicated by Band ID 531. In Async Mode, communication on each link is performed asynchronously, so if the channels used by each link are close together, there is a risk of communication interference. The distance between channels between links required for proper decoding of the signals on each link varies depending on the communication device, so this field is used to notify capability information. For example, if the value of Async Mode CH Distance 534 is 4, it indicates that the transmitting device of the Element requires a channel spacing of at least 4 channels or more in Async Mode. Note that if the aforementioned Async Mode Support 523 contains information indicating that Async Mode is not supported, this field may contain a value of 0, or this field may be omitted. Furthermore, in this embodiment, the required channel spacing 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 all frequency bands may be used. Specifically, this field may be included in Common Info 511.

[0102] Furthermore, when operational information is indicated by the Multi-Link Capability Element, this field may also include information indicating the channel spacing actually used in the Async Mode of multi-link communication. For example, when communication device 102, which is an AP, sends an Association Response that includes this Element, this field includes information indicating the channel spacing of the multiple links established by the exchange of this association.

[0103] Alternatively, when request information is indicated by the Multi-Link Capability Element, this field may include information indicating the channel interval to be requested for use in the Async Mode of multilink communication. It may also include information indicating the minimum channel interval supported in the Async Mode of multilink communication with the partner device. When operational information is indicated by this Element, this field contains a value greater than or equal to the larger of the channel interval indicated by the communication device 102 as capability information and the channel interval indicated by the communication device 103 as capability information. Furthermore, if Async Mode Support 523 contains information indicating that Async Mode will not be executed, or if Async Mode Support 523 is omitted, this field may contain a value of 0. Alternatively, this field may be omitted. Alternatively, when the communication device 103, which is an STA, sends an Association Request including this Element, this field indicates the channel interval that the communication device 103 requests in Async Mode with the communication device 102. Note that if the communication device 103 does not request the execution of Async Mode, this field may contain a value of 0, or it may be omitted. Note that this field may be omitted when the Multi-Link Capability Element is used to indicate operational or request information.

[0104] Max Link Number 535 is a field containing capability information indicating the maximum number of links supported by the transmitting device that transmitted the Element when performing multilink communication in the frequency band indicated by Band ID 531. If the Band Combination Info 525 mentioned above does not contain information indicating support for multilink communication between links in the same frequency band, this field may contain a value of 0. Alternatively, this field may be omitted. Furthermore, although this embodiment allows for the maximum number of links to be indicated for each frequency band, it is not limited to this, 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] Furthermore, when operational information is indicated by the Multi-Link Capability Element, this field may indicate the total number of links actually used in multi-link communication within the frequency band indicated by Band ID 531. For example, when communication device 102, which is an AP, sends an Association Response that includes this Element, this field includes information indicating the number of links (one or more) established by the exchange of this association. For example, if communication devices 102 and 103 establish two links at 2.4 GHz, this field will contain the value 2.

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

[0107] Supported Nss536 is a field containing capability information indicating the maximum number of (spatial) streams supported by the transmitting device that sent the Element when performing multilink communication in the frequency band indicated by Band ID 531. Nss stands for Number of Special Streams. The number of streams indicated in this field is the number of streams in MIMO communication. If MIMO communication is not supported in multilink communication in the frequency band indicated by Band ID 531, this field will contain a value of 0 or 1, or this field will be omitted. In this embodiment, the maximum number of streams can be indicated for each frequency band, but it 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 Info511.

[0108] When operational information is indicated by the Multi-Link Capability Element, this field may also indicate the number of streams actually used in multilink communication in the frequency band indicated by Band ID 531. For example, when communication device 102, which is an AP, sends an Association Response that includes this Element, this field includes information indicating the number of MIMO communication streams actually executed by the exchange of this association. For example, if communication devices 102 and 103 perform MIMO communication with 3 streams on a link performing multilink communication at 2.4GHz, this field will contain the value 3. If MIMO communication is not performed, this field may contain the value 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, sends an Association Request including this Element, this field indicates the number of streams that the communication device 103 requests for MIMO communication in multi-link communication. If the communication device 103 does not request MIMO communication, this field may contain a value of 0 or 1, or this field may be omitted. Furthermore, even when the Element indicates operational information or request information, this field may include capability information indicating the maximum number of streams that the transmitting device of the Element supports for MIMO communication in multi-link communication.

[0110] Per Link Info 513 is a field comprising the fields Link ID 541, Band ID 542, Bandwidth 543, CH 544, and Nss 545. When capability information is indicated by the Multi-Link Capability Element, Per Link Info 513 indicates information about the channels on which the Element's transmitter supports multilink communication. In this case, the set of Per Link Info 513 will include as many entries as there are channels (links) on which the Element's transmitter supports multilink communication. Alternatively, when capability information is indicated by the Element and multilink communication links have already been established, Per Link Info 513 indicates information about the already established links. In this case, the set of Per Link Info 513 may include as many entries as there are already established links. Also in this case, the links on which communication device 102 indicates information by Per Link Info 513 are those established with communication device 103 and at least one of the other communication devices. In this case, the link that communication device 103 indicates by Per Link Info 513 is one that has been established with communication device 103 and at least one of other communication devices. Alternatively, if capability information is indicated by the Element, Per Link Info 513 may not be included. This is not limited to cases where operational information is indicated by a Multi-Link Capability Element and communication device 102, which is an AP, sends an Association Response that includes the Element. In this case, Per Link Info 513 indicates information about the links established by the exchange of this association. In this case, Per Link Info 513 will be included for each link established by the exchange of this association. Also, if communication device 103 indicates request information by sending an Association Request that includes the Element, Per Link Info 513 indicates information about the links that communication device 103 requests to be established.In this case, Per Link Info 513 will include the number of links that the communication device 103 requests to establish.

[0111] Link ID541 is a field that contains an identifier for identifying the link.

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

[0113] Bandwidth543 is a field containing information indicating the bandwidth of the link indicated by Link ID541. This field is displayed in the same way as Supported Bandwidth532. When capability information is indicated by Multi-Link CapabilityElement, this field indicates the bandwidth supported on the link indicated by Link ID541. Furthermore, when communication device 102, which is an AP, indicates operational information by sending an Association Response that includes this Element, this field indicates the bandwidth used on the link indicated by Link ID541. Furthermore, when communication device 103, which is an STA, indicates request information by sending an Association Request that includes this Element, this field indicates the bandwidth requested by communication device 103 on the link indicated by Link ID541.

[0114] CH544 is a field containing information indicating the frequency channel of the link indicated by Link ID 541. This field may contain the number of channels directly, or the channels may be indicated as shown in Table 4. When capability information is indicated by the Multi-Link Capability Element, this field indicates the channels supported on the link indicated by Link ID 541. Furthermore, when communication device 102, which is an AP, indicates operational information by sending an Association Response that includes this Element, this field indicates the channels used on the link indicated by Link ID 541. Furthermore, when communication device 103, which is an STA, indicates request information by sending an Association Request that includes this Element, this field indicates the channels requested by communication device 103 on the link indicated by Link ID 541.

[0115] Furthermore, Nss545 is a field that contains information indicating the number of MIMO communication streams on the link indicated by Link ID 541. If MIMO communication is not performed, this field may contain a value of 0 or 1, or this field may be omitted. When capability information is indicated by the Multi-Link Capability Element, this field indicates the maximum number of streams supported on the link indicated by Link ID 541. When communication device 102, which is an AP, indicates operational information by sending an Association Response that includes this Element, this field indicates the number of streams used on the link indicated by Link ID 541. When communication device 103 indicates request information by sending an Association Request that includes this Element, this field indicates the number of streams requested by communication device 103 on the link indicated by Link ID 541.

[0116] By sending and receiving MAC frames that include the Multi-Link Capability Element described above, communication devices 102 and 103 exchange multi-link communication capability information, operational information, and request information. In this embodiment, multi-link communication capability information, operational information, and request information are shown by the same Multi-Link Capability Element, but this is not limited to this. Capability information and operational information, or capability information and request information, may each be shown by different Information Elements. In this case, for example, capability information may be shown by an Element that includes Common Info 511 and Per Band Info 512. Operational information and request information may also be shown by an Element that includes Common Info 511 and Per Link Info 513. Furthermore, when capability information is shown by a Multi-Link Capability Element, some fields may show operational information or request information. Alternatively, when operational information or request information is shown by a Multi-Link Capability Element, some fields may show capability information.

[0117] In Figure 5, the Multi-Link Capability Element is assumed to include fields for Primary CH521, Supported CH533, and CH544 as information indicating the frequency channel. However, the Multi-Link Capability Element is not limited to these; it is sufficient for the Multi-Link Capability Element to include at least one of Primary CH521, Supported CH533, and CH544 as information indicating the frequency channel.

[0118] Furthermore, the names of each field, the number of fields, and the order of the fields are not limited to those shown in Figure 5. Any field may be included before or after any of the fields shown in Figure 5. Also, a field included in Common Info511 may be included in Per Band Info512 or Per Link Info513. Similarly, a field included in Per Band Info512 or Per Link Info513 may be included in the other field or in Common Info511. In addition, any of the fields shown in Figure 5 may be omitted.

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

[0120] Figure 8 shows the information contained in the body portion of the MAC frame of a Beacon transmitted by the communication device 102. The Beacon contains various pieces of information as elements, as shown in the Information column. This information is 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 Figure 8; it is sufficient if it contains at least some of it.

[0121] Of this information, Order=1 (Timestamp), Order=2 (Beacon interval), and Order=3 (Capability Information) are essential information for a Beacon. Additionally, Order=4 (SSID) and Order=5 (Supported Rates and BSS Membership Selectors) are also essential information for a Beacon.

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

[0123] The Beacon interval contains information indicating the interval at which the MAC frame transmitter sends Beacons.

[0124] Capability Information includes information indicating whether the MAC frame sender is capable of performing a Point Coordination Function (PCF). It also includes information indicating whether the MAC frame sender requires encryption for data communication.

[0125] The SSID contains information indicating the ESS or IBSS identifier of the MAC frame transmitter. ESS stands for Extended Service Set, and IBSS stands for Independent Basic Service Set. The ESS identifier includes the AP's identification name, ESSID. Generally, the SSID is included as the ESSID.

[0126] Supported Rates and BSS Membership Selectors contain information indicating the wireless transmission rates supported by the Beacon transmitter.

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

[0128] In this embodiment, the destination information shown in Figure 10 (described later) is placed as an Order=Z element that is communicated after the EHT Capabilities Element and the EHT Operation Element, as shown in Figure 8. Here, the name of the element indicating the destination information for multilink communication is referred to as the destination link information, but this is not limited to this. For example, it may be named as a Multi-link report element. Furthermore, the destination information is placed so that it is communicated before the Vendor Specific Element, which is the last element communicated in the MAC frame.

[0129] The EHT Capabilities Element contains information indicating the MAC frame transmitter's ability to communicate in accordance with the IEEE 802.11be standard. Specifically, it may include, for example, information indicating the MAC frame transmitter's PHY capability in IEEE 802.11be communication (EHT PHY Capabilities Information). In addition to this, or alternatively, it may also include information indicating the MAC capability in IEEE 802.11be communication (EHT MAC Capabilities Information). By transmitting the EHT Capabilities Element, the MAC frame transmitter can indicate that its device is capable of IEEE 802.11be communication. The EHT Capabilities Element may be transmitted in a Beacon after the element with Order=87.

[0130] The EHT Operation Element contains information for controlling communication devices in communications compliant with the IEEE 802.11be standard. The operation of communication devices that support communications compliant with the IEEE 802.11be standard and participate in a BSS compliant with the IEEE 802.11be standard is controlled by the EHT Operation Element. The EHT Operation Element may be communicated in a Beacon after the EHT Capabilities Element.

[0131] When a Beacon transmitter sends a Beacon containing multilink communication destination information, the Beacon includes at least one of the EHT Capabilities Element and the EHT Operation Element. Compatibility can be ensured by transmitting the multilink communication destination information after at least one of the EHT Capabilities Element and the EHT Operation Element. Communication devices that only support standards prior to IEEE 802.11ax will not be able to understand the contents of the multilink communication destination information even if they receive it, and will discard the information after the destination information. For example, if the destination information is transmitted before the information regarding communication compliant with the IEEE 802.11ax standard, the receiving device may not be able to obtain the information regarding the transmitter's communication compliant with the IEEE 802.11ax standard. By arranging the multilink communication destination information to be transmitted after EHT Capabilities and EHT Operation, the Beacon receiver can obtain information regarding communication for standards prior to IEEE 802.11be.

[0132] Furthermore, in addition to the above, multilink migration destination information should be configured so that it is communicated at least after the SSID and Supported Rates and BSS MembershipSelectors in the Beacon. By configuring the multilink migration destination information to be communicated after the information that is essential to the Beacon, even receivers that only support standards prior to IEEE 802.11ax can obtain the essential information contained in the Beacon. This ensures compatibility with legacy terminals (those that only support standards prior to IEEE 802.11ax).

[0133] Similarly, the Multi-link Capability Element shown in Figure 5 is positioned to communicate after at least one of the EHT Capabilities Element and the EHT Operation Element. This ensures compatibility with legacy devices. However, the Multi-link Capability Element may also be positioned to communicate after the SSID and Supported Rates and BSS Membership Selectors. This also ensures compatibility with legacy devices.

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

[0135] Similar to Beacons, Probe Responses must include Order=1 (Timestamp), Order=2 (Beacon interval), and Order=3 (Capability Information). In addition, Order=4 (SSID) is also mandatory. Unlike Beacons, Order=5 (Supported Rates and BSS Membership Selectors) may or may not be included.

[0136] In this embodiment, the migration destination information shown in Figure 10 (described later) is placed as an Order=Z element that is communicated after the EHT Capabilities Element and the EHT Operation Element, as shown in Figure 9. Here, the name of the element indicating the migration destination information for multilink communication is referred to as the migration destination link information, but it is not limited to this. For example, it may be named as a Multi-link report element. Furthermore, the migration destination information is placed so that it is communicated before the Vendor Specific Element, which is the second to last element communicated in the MAC frame. By placing the migration destination information so that it is communicated after at least one of the EHT Capabilities Element and the EHT Operation Element, compatibility with legacy terminals can be ensured.

[0137] Furthermore, in addition to this, the destination information for multilink connections should be arranged so that it is communicated after the SSID in the Probe Response. This ensures compatibility with legacy devices.

[0138] Furthermore, if the Probe Response transmitter contains information indicating that it is requesting destination information for multilink communication, it may transmit the destination information without transmitting other elements after the SSID. By not transmitting unnecessary elements, the Probe Response transmitter can reduce the number of elements to communicate and lower overhead.

[0139] Furthermore, the Multi-link Capability Element shown in Figure 5 is positioned so that it communicates after at least one of the EHT Capabilities Element and the EHT Operation Element. This ensures compatibility with legacy devices. However, the Multi-link Capability Element may also be positioned so that it communicates after the SSID. This also ensures compatibility with legacy devices.

[0140] Figure 10 shows an example of the frame format for the destination link information element (Information Element). The destination link information with Order=Z shown in Figures 8 and 9 includes the information shown in Figure 10.

[0141] The destination link information element has the fields Element ID 1101, Length 1102, Element ID Extension 1103, and Number of Links 1104. In addition, the destination link information element has the field Optional Subelements 1105. The communication device 102 generates the destination link information elements shown in Figure 10 sequentially, starting with Element ID 1101, and transmits them to other communication devices. In this case, the communication device 102 generates all fields in the frame before transmitting. Alternatively, the communication device 102 may transmit the fields in parallel with generating them. Specifically, the communication device 102 may, for example, generate Length 1102 in parallel with transmitting the generated Element ID 1101.

[0142] Element ID 1101 contains a value that indicates this element is a destination link information element.

[0143] Length1102 contains information specifying the number of octets in the destination link information element that follows Length1102 (but does not include Length1102).

[0144] Element ID Extension 1103 contains a value to identify different elements that have the same Element ID assigned to them. In the IEEE 802.11be standard, this field is omitted if an Element ID Extension is not assigned to the destination link information element.

[0145] The Number of Links 1104 field contains information indicating the number of links indicated in the destination link information element. This field is in unsigned integer format. The length of this field is assumed to be 9 bits to distinguish between 0 and 511, but it may be more or less. By including this field in the destination link information, the receiving device for the destination link information can identify the number of links indicated in the destination link information without having to parse the subsequent Optional Subelements 1105. Note that the number of links indicated can be obtained by parsing Optional Subelements 1105, so this field may be omitted.

[0146] Optional Subelements1105 contains information about each link. Optional Subelements1105 includes Link Reports1111~111m as sub-elements (or sub-fields) for each link whose information is provided in the destination link information element.

[0147] The communication device 102 that transmits the destination link information transmits information about at least one link already established with the communication device 103, excluding the link used to transmit the destination link information. In addition to this, or instead, the communication device 102 may transmit information about links that can be established with the communication device 103. Specifically, it transmits information about a wireless network that the communication device 102 has already built, even though it has not yet established a link with the communication device 103. In addition to this information about links, the communication device 102 may also transmit information about the link used to transmit the destination link information.

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

[0149] In this embodiment, the frame format for the Link Report shall be the frame format for the Neighbor Report element as defined in the IEEE 802.11 series standard. However, the frame format for the Link Report is not limited to that of the Neighbor Report.

[0150] Subelement ID 1121 contains information indicating that this subelement is a Link Report. If a Neighbor Report is used as a Link Report, ID 52 will be included to indicate that it is a Neighbor Report. Note that this field may be omitted.

[0151] Length1122 contains information specifying the number of octets in the Link Report after Length1122 (excluding Length1122).

[0152] BSSID1123 contains information indicating the BSSID as identification information for the wireless network on which the link shown in the Link Report is established. Alternatively, instead of or in addition to BSSID1123, a Link ID field may be included as identification information for the link. Note that when indicating information for a link that has not yet been established, the Link ID field may be omitted, or the Link ID field may contain a value indicating that the link has not yet been established.

[0153] BSSID Information1124 includes information indicating whether the wireless network indicated by BSSID1123 is capable of communication compliant with the IEEE 802.11be standard. In addition, it may also include information indicating whether the wireless network indicated by BSSID1123 is capable of communication compliant with the IEEE 802.11ax or IEEE 802.11n standards. Note that this field may be omitted.

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

[0155] Channel Number 1126 contains information indicating the frequency channel used within the wireless network indicated by BSSID 1123. Note that if the Link Report indicates information about an already established link, Channel Number 1126 may also include information indicating the frequency channel used by that link.

[0156] PHY Type 1127 contains information indicating the Physical Medium Type of the MAC frame that contains the destination link information element.

[0157] Optional Subelements 1128 contains information about the link. Optional Subelements 1128 contains one or more Measurement Report fields. Measurement Reports 1131 to 113n are included in Optional Subelements 1128 in quantities equal to the number of types of information about the link in question. The information about the link includes information indicating the availability of transmission opportunities for communication device 102 or 103, which is used to determine link switching and selection in multilink communication. For example, the information about the link may include information indicating the percentage of time during which the frequency channel used for the link in question is busy or not busy within a given period. Alternatively, it may include information indicating whether signals transmitted from other communication devices or radar have been detected on the frequency channel used for the link in question. Alternatively, it may include information indicating the power of the signal received by communication device 102 on the frequency channel used for the link in question. Note that the power of the signal received by communication device 102 refers to the power of the signal transmitted from communication device 103 and received by communication device 102. Alternatively, it may include information indicating the signal-to-noise ratio for the frequency channel used in the link, or information regarding the total power of noise and interference waves. Alternatively, it may include information regarding the number of management frames and data frames received through the link or the wireless network establishing the link. The communication device 102 only needs to include at least one of the above pieces of information as a Measurement Report in Optional Subelements 1128 for each link.

[0158] Measurement Reports 1131-113n include the fields SubelementID 1141, Length 1142, and Measurement Token 1143. In addition to these fields, they also include the fields Measurement Report Mode 1144, Measurement Type 1145, and Measurement Report 1146.

[0159] Subelement ID 1141 contains information indicating that this subelement is a Measurement Report. This field may be omitted.

[0160] Length1142 contains information specifying the number of octets in the Measurement Report after Length1142 (excluding Length1142).

[0161] Measurement Token 1143 contains the same value as the Measurement Token of the Measurement Request element received from communication device 103. Communication device 103 can request communication device 102 to send destination link information by sending a Probe Request including the Measurement Request element to communication device 102. Communication device 102 may send a Measurement Request frame including the Measurement Request element instead of a Probe Request. The Measurement Request frame may be sent at any time. Also, if communication device 102 sends Measurement Reports 1131 to 113n without receiving a Measurement Request element, Measurement Token 1143 will be set to 0. This field may be omitted.

[0162] Measurement Type 1145 includes information indicating the type of information contained in Measurement Report 1146, which will be described later. The information contained in Measurement Report 1146 refers to the information related to the links mentioned above.

[0163] In this embodiment, the Measurement Type may be specified to indicate a type of information that does not apply to the Neighbor Report element but does apply to other elements in standards prior to IEEE 802.11ax. 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 contains information about the frequency channel, the start time of the measurement, and the length of the measurement period, regardless of the Measurement Type. It also contains information about the type indicated by the Measurement Type under these conditions. The Measurement Report field is sometimes called the [Measurement Type Name] Report based on the type specified in Measurement Type. For example, if the Measurement Type is Basic, the Measurement Report field is called the Basic Report.

[0165] If Measurement Type 1145 indicates Basic, Measurement Report 1146 (Basic Report) includes information indicating whether a valid MPDU was received from another BSS. MPDU stands for Medium Access Control (MAC) Protocol Data Unit. In addition to this information, or alternatively, it includes information indicating whether a sequence of short training symbols not followed by a valid SIGNAL field was received. In addition to this information, or alternatively, it includes information indicating whether a large power signal that cannot be identified as either a radar wave, an OFDM preamble, or a valid MPDU was received, or whether a radar wave was received.

[0166] If Measurement Type 1145 indicates CCA, Measurement Report 1146 (CCA Report) will include information such as the percentage of time the frequency channel is busy.

[0167] If Measurement Type 1145 indicates an RPI Histogram, Measurement Report 1146 includes information such as a frequency distribution with power observed by the antenna as the class. In this case, Measurement Report 1146 may also be called an RPI Histogram Report.

[0168] If Measurement Type 1145 indicates Channel Load, Measurement Report 1146 (Channel Load Report) includes information such as the percentage of time the frequency channel is busy. In addition, or alternatively, it may include information regarding switching to a new bandwidth.

[0169] If Measurement Type 1145 indicates a Noise Histogram, Measurement Report 1146 (Noise Histogram Report) includes information showing the total average power of noise and interference waves. In addition, or alternatively, it may include information showing the frequency distribution with the total power of noise and interference waves as the class.

[0170] If Measurement Type 1145 indicates a beacon, Measurement Report 1146 (Beacon Report) includes information such as the beacon's received power and signal-to-noise ratio. Alternatively, it may include, in addition to or instead of, information such as the received power and signal-to-noise ratio of the Measurement Pilot or Probe Response frame.

[0171] If Measurement Type 1145 indicates a Frame, Measurement Report 1146 (Frame Report) includes information indicating the average power of the received frame. Alternatively, it may include, in addition to or instead of this, information such as the signal-to-noise ratio and the number of received data frames and management frames.

[0172] In this embodiment, as shown in Figure 10, all destination information is included in a single element (destination link information element). However, the communication device 102 is not limited to this and may include multiple elements independently as destination information. Specifically, instead of the destination link information element shown in Figure 10, Link Reports 1111 to 111m may be included in the MAC frame as elements rather than as sub-elements. 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. These fields store identifiers corresponding to the element. When a Neighbor Report is used as a Link Report, 52 is included as the ID indicating the Neighbor Report.

[0173] Furthermore, in this embodiment, the Link Report includes sub-elements of Measurement Reports 1131 to 113n as link-related information, but this is not limited to this. Instead of the Measurement Report, other elements specified in the IEEE 802.11 series standards that contain 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, as defined in standards prior to IEEE 802.11ax, may be included as sub-elements. Alternatively, or in addition to these, elements such as Extended BSS Load or HE BSS Load may be included as sub-elements. A single Link Report may include one or more of these elements as sub-elements. Alternatively, a Measurement Report sub-element may include at least one of the above elements as a sub-element.

[0175] When the elements described above are treated as sub-elements, the ElementID field of these elements is replaced with a Subelement ID field. The Subelement ID field then stores an identifier for identifying the sub-element within the Measurement Report or Link Report. If an Element ID Extension field exists, it is deleted. However, the Subelement ID field stores an identifier corresponding to the combination of the values ​​in the Element ID field and the Element ID Extension field.

[0176] BSS Load includes information such as the number of STAs included in the target BSS, the percentage of time the media is busy, and the total remaining time of the media available due to admission control.

[0177] BSS Average Access Delay includes information such as the average media access delay time of the access point (AP).

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

[0179] Extended BSS Load has Multi-User (MU) beamform-me capability and includes information indicating the number of VHT STAs associated with the target BSS. In addition, or alternatively, it includes information indicating the unused rate in the spatial stream domain during busy media times, and information indicating the temporal utilization rate of the secondary 20MHz, 40MHz, or 80MHz bandwidths.

[0180] The HE BSS Load includes information such as the number of HE STAs associated with the target BSS, and the percentage of time the media is busy for communication between the AP and the HE STA. HE STA refers to an STA that supports wireless communication compliant with the IEEE 802.11ax standard. In addition, or alternatively, it may also include information indicating the unused rate in the frequency domain during busy media times, and information indicating the unused rate in the spatial stream domain during busy media times.

[0181] In addition to these elements, or as an alternative, the Link Report or Measurement Report may include sub-elements that are not specified in standards prior to IEEE 802.11ax. In this embodiment, one such element is called the EHT BSS Load. The EHT BSS Load includes information indicating the number of EHT STAs associated with the target BSS. An EHT BSS refers to an STA that supports wireless communication compliant with the IEEE 802.11be standard. The number of EHT STAs is calculated by counting STAs that include at least one of EHT Capabilities and EHT Operation in their management frame. In addition to this, or as an alternative, the report may include information indicating the percentage of time the media is busy for communication between the AP and the EHT STA, and information indicating the unused rate in the frequency domain during the busy time of the media. In addition to this, or as an alternative, the report may also include information indicating the unused rate in the spatial stream domain during the busy time of the media.

[0182] Figure 6 is a flowchart showing the process that is executed when the communication device 103 performs multilink communication, by the control unit 202 reading and executing a computer program stored in the memory unit 201.

[0183] This flowchart starts when the power to the communication device 103 is turned on. Alternatively, the communication device 103 may start when a user or application instructs it to start multilink communication. Alternatively, the communication device 103 may start when the amount of data to be transmitted to the communication device 102 exceeds a predetermined threshold.

[0184] First, communication device 103 acquires capability information for multilink communication from the other device (S601). Specifically, communication device 103 acquires capability information for communication device 102 by receiving a Beacon containing a Multi-Link Capability Element transmitted by communication device 102. Alternatively, communication device 103 may perform this step by receiving a Probe Response containing a Multi-Link Capability Element transmitted by 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 other device of its capabilities in multilink communication (S602). Specifically, the communication device 103 notifies the other device of its capabilities in multilink communication by sending a Probe Request that includes a Multi-Link Capability Element. If the capabilities information of the other device has been obtained before this step, the communication device 103 may determine the capabilities information to notify based on the capabilities information of the other device. Specifically, the communication device 103 may determine the capabilities information to notify in this step so as not to exceed the capabilities of the communication device 102. For example, consider a case where the communication device 103 supports multilink communication at 2.4GHz, 5GHz, and 6GHz, and the communication device 102 supports only 2.4GHz and 5GHz. In this case, the communication device 103 notifies in this step that it supports multilink communication at 2.4GHz and 5GHz as capabilities information. Note that if the communication device 103 sends an Association Request to the communication device 102 in S603, which will be described later, that includes request information indicating a request for multilink communication, the processing in this step may be omitted.

[0186] Next, the communication device 103 sends an AssociationRequest containing information requesting multilink communication (S603). The request information sent in this step indicates information regarding the multilink communication that the communication device 103 requests to be performed. In this step, the communication device 103 may also send an AssociationRequest that does not include the request information.

[0187] The communication device 103 determines whether it has received an Association Response from the AP (Application Platform) communication device 102 (S604). If the communication device 103 has not received an Association Response, it determines No in this step and repeats the process in this step. If a predetermined amount of time has elapsed since sending the Association Request in S603 and it has not determined Yes in this step, the communication device 103 notifies the user of an error and terminates the processing of this flow. On the other hand, if the communication device 103 has received an Association Response, it determines Yes in this step and proceeds to the process in S605.

[0188] Communication device 103 initiates multilink communication with communication device 102 (S605). If the Association Response received in S604 contains operational information for multilink communication, it initiates multilink communication based on that operational information. Alternatively, if request information was sent in S603 and an Association Response containing only permission information was received in S604, it initiates multilink communication based on the request information sent in S603. In this embodiment, in S605, multilink communication is initiated via multiple links established with communication device 102.

[0189] When communication device 103 starts multilink communication with communication device 102, it obtains multilink communication transition information from communication device 102 (S606). Specifically, communication device 103 receives a Beacon containing the transition link information element shown in Figure 10 from communication device 102. Communication device 103 may also receive a Beacon containing the transition link information element from communication device 102 at each Beacon Interval of communication device 102. In addition to the transition link information element, the Beacon received in this step may also include a Multi-Link CapabilityElement indicating the capability information of communication device 102 in multilink communication.

[0190] In this embodiment, the communication device 103 receives a Beacon in S606, but it is not limited to this, and may also receive a Probe Response that includes a destination link information element. In this case, between S605 and S606, the communication device 103 sends a Probe request to the communication device 102 to request destination information. The Probe Request sent by the communication device 103 may include information indicating that destination information is being requested. The Probe Response does not necessarily have to include a Multi-Link Capability Element that indicates the communication device 102's capability information in multi-link communication.

[0191] The communication device 103 determines whether to change the link used for multilink communication with the communication device 102 (S607). Specifically, the communication device 103 determines whether the user has instructed it to change the link. If the user has instructed it to change the link, the communication device 103 determines Yes in this step and proceeds to S608. On the other hand, if the user has not instructed it to change the link, the communication device 103 determines No in this step and proceeds to S609. In this case, the communication device 103 may display the destination information indicated by the destination link information element acquired in S606 on the display unit and display a screen asking the user whether to change the link. Alternatively, the communication device 103 may make the determination in this step based on the destination link information element acquired in S606, not limited to user instructions. For example, communication device 103 compares the likelihood of obtaining a transmission opportunity on the link currently used for data communication with communication device 102 with the likelihood of obtaining a transmission opportunity on other links indicated by the destination link information element, and makes the determination in this step. In this case, if communication device 103 has a higher likelihood of obtaining a transmission opportunity on other links compared to the link currently in use, it determines Yes in this step. On the other hand, if communication device 103 has a lower likelihood of obtaining a transmission opportunity on other links compared to the link currently in use, it determines No in this step. In this case, a link with a lower percentage of the time the frequency channel used for the link is busy per predetermined period is considered to have a higher likelihood of obtaining a transmission opportunity. Also, a link with a higher signal-to-noise ratio is considered to have a higher likelihood of obtaining a transmission opportunity. Alternatively, a link with a higher power of the signal received on the frequency channel used for the link is considered to have a higher likelihood of obtaining a transmission opportunity. Also, a link with a lower total power of noise and interference waves on the frequency channel used for the link is considered to have a higher likelihood of obtaining a transmission opportunity. Furthermore, links with fewer management frames and data frames received via the established wireless network are considered to have a higher probability of obtaining transmission opportunities.Alternatively, if the communication device 103 is not achieving the desired throughput on the link used for data communication with the communication device 102, it will determine "Yes" in this step. The throughput threshold may be set by the user or may be preset in the communication device 103.

[0192] In this embodiment, the destination information is obtained in S606 and then the decision to change the link is made in S607, but this is not limited to this configuration. The communication device 103 may first determine whether the user has issued a link change instruction before obtaining the destination information. After S605, the communication device 103 makes the decision in S607 based on the user instruction, and if it determines Yes, it sends a Probe Request to the communication device 102 to request the destination information. Subsequently, the communication device 103 obtains the destination information from the communication device 102 (S606) and performs the processing in S608 described later based on the obtained destination information. If it determines No in S607, the communication device 103 performs the processing in S609 described later.

[0193] If the communication device 103 determines "Yes" in S607, it performs a link change process (S608). Specifically, the link change process involves switching the link used for data communication with communication device 102 to a different link. Alternatively, it may add another link to be used for data communication with communication device 102. Alternatively, communication device 103 may establish a new link with communication device 102 and switch or increase the number of links used for data communication with communication device 102. In addition to the link used for data communication with communication device 102, communication device 103 may also perform a change process on the link used to transmit control frames.

[0194] In S608, communication device 103 sends a link change request to communication device 102. Based on the response received from communication device 103 to the change request it sent, communication device 102 starts data communication on the new link. Alternatively, when establishing a new link with communication device 102, communication device 103 may send an Association Request in S608, similar to S604. In this case, based on the receipt of an Association Response from communication device 102, communication device 103 starts data communication on the new link.

[0195] In this case, communication device 103 may send link change requests and association requests via the frequency channel used for communication of management frames with communication device 102. Alternatively, communication device 103 may send these signals via the frequency channel used for data communication.

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

[0197] Communication device 103 disconnects the link with communication device 102 (S610). In this case, communication device 103 disconnects all but one of the multiple links established with communication device 102. Specifically, communication device 103 sends a Disassociation frame to communication device 102 containing information that identifies the link to be disconnected. Communication device 103 may send the Disassociation frame through the link to be maintained without disconnection, or it may send the Disassociation frame through any one of the links to be disconnected. In this embodiment, one link with communication device 102 is maintained, but this is not limited to this, and all links may be disconnected in this step. After executing the process in S610, communication device 103 terminates the processing of this flow.

[0198] Note that the communication device 103 may make the determination in S609 based on whether a link for multilink communication with the communication device 102 is maintained, rather than on user instructions. In this case, the communication device 103 skips S610. If multiple links are maintained between the communication device 103 and the communication device 102, the communication device 103 determines No in S609. On the other hand, if multiple links are not maintained between the communication device 102 and the communication device 103, 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 between the communication device 102 and the communication device 102, and No if no links are maintained.

[0199] As shown in Figure 6, after initiating multilink communication with communication device 102, communication device 103 can change the link of the multilink communication with communication device 102 by acquiring destination information. This allows communication device 103 to prevent a decrease in throughput during multilink communication with communication device 102 and improve communication efficiency.

[0200] Figure 7 is a flowchart showing the process that is executed when the communication device 102 performs multilink communication, by the control unit 202 reading and executing a computer program stored in the memory unit 201.

[0201] This flowchart starts when the power to the communication device 102 is turned on. Alternatively, the communication device 102 may start when a user or application instructs it to start multilink communication. Alternatively, the communication device 102 may start when the amount of data to be transmitted to the communication device 103 exceeds a predetermined threshold.

[0202] First, the communication device 102 notifies the other device of its capabilities in multilink communication (S701). Specifically, the communication device 102 notifies the other device of its capabilities in multilink communication by transmitting a Beacon containing a Multi-Link Capability Element. Alternatively, the communication device 102 may perform this step by transmitting a Probe Response containing 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 the capability information for multilink communication of the other device (S702). Specifically, the communication device 102 acquires the capability information for multilink communication of the other device by receiving a Probe Request that includes a Multi-Link Capability Element. If the communication device 102 does not receive a Probe Request that includes a Multi-Link Capability Element from the other device, this step may be omitted.

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

[0205] The communication device 102 determines whether it has received an Association Request from the communication device 103 (S703). If the communication device 102 has not received an Association Request, it determines No in this step and repeats the process in this step. If a predetermined amount of time has elapsed since sending the Probe Response in S702 and the result is not Yes in this step, the communication device 102 notifies the user of an error and terminates the processing of this flow. On the other hand, if the communication device 102 has received an Association Request, it determines Yes in this step and proceeds to the process in S704.

[0206] Next, communication device 102 sends an Association Response in response to the Association Request (S704). If request information was not received from communication device 103 in S703, communication device 102 sends an Association Response that includes operational information for multilink communication with communication device 103. In this case, communication device 102 decides what operational information to include in the Association Response based on the capabilities information of communication device 103 for multilink communication. The operational information that communication device 102 includes in the Association Response indicates information about the multilink communication actually conducted between communication devices 102 and 103. Note that even if the Association Request received in S703 includes request information from communication device 103, communication device 102 may still send an Association Response that includes operational information. In this case, communication device 102 decides what operational information to include in the Association Response based on the request information from communication device 103 in the received Association Request. Alternatively, if the communication device 103 has received request information in S703, the communication device 102 may send an Association Response that includes only information indicating whether or not to permit multilink communication.

[0207] Communication device 102 initiates multilink communication with communication device 103 (S705). If the Association Response transmitted in S704 contains operational information for multilink communication, multilink communication is initiated based on that operational information. Alternatively, if request information is received in S703 and an Association Response containing only permission information is transmitted in S704, multilink communication is initiated based on the request information received in S703. In this embodiment, in S705, multilink communication is initiated via multiple links established with communication device 103.

[0208] When the communication device 102 starts multilink communication, it notifies the destination information for the multilink communication (S706). Specifically, the communication device 102 transmits a Beacon containing the destination link information elements shown in Figure 10. The communication device 102 may also transmit a Beacon containing the destination information at each Beacon Interval. In this step, the communication device 102 may also transmit the capability information transmitted in S701 in addition to the destination information.

[0209] In this embodiment, the communication device 102 transmits a Beacon containing destination information in this step, but it is not limited to this, and may also transmit a Probe Response containing destination information. In this case, the communication device 102 includes a step between S705 and S706 to determine whether it has received a Probe Request. If the communication device 102 determines that it has received a Probe Request, it performs the process in S706, and if it determines that it has not received one, it determines again whether it has received a Probe Request.

[0210] Furthermore, the communication device 102 may send a Probe Response containing different information depending on the device that sent the Probe Request. Specifically, if the communication device 102 receives a Probe Request sent from a device that has already started multilink communication (communication device 103 in this embodiment), it sends a Probe Response that includes migration destination information. In this case, the Probe Response does not need to include information on the capability of multilink communication. On the other hand, if the communication device 102 receives a Probe Request sent from a device that has not started multilink communication, it sends a Probe Response that does not include information on the migration destination. In this case, the Probe Response includes information on the capability of multilink communication. By changing the information included in the Probe Response depending on the device that sent the Probe Request, the amount of information to be communicated can be reduced, and overhead can be minimized.

[0211] Furthermore, the communication device 102 may send a Probe Response containing different information depending on whether the received Probe Request contains information indicating a request for destination information. If the communication device 102 receives a Probe Request that contains information indicating a request for destination information, it sends a Probe Response that includes destination information. In this case, the Probe Response does not need to include information on the capabilities of multilink communication. On the other hand, if the communication device 102 receives a Probe Request that does not contain information indicating a request for destination information, it sends a Probe Response that does not include destination information. In this case, the Probe Response includes information on the capabilities of multilink. In this way, by changing the information to be included in the Probe Response depending on whether or not the Probe Request contains information indicating a request for destination information, the amount of information to be communicated can be reduced and overhead can be minimized.

[0212] When the communication device 102 receives the 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, it is a communication device different from the communication device 103. If the user instructs the communication device 102 to start multilink communication with another communication device, it determines Yes in this step and proceeds to S702. On the other hand, if the user does not instruct the communication device 102 to start multilink communication, it determines No in this step and proceeds to S708.

[0213] In addition, the communication device 102 may make a determination in S707 based on whether it has received a Probe Request from another communication device, not limited to user instructions. In this case, the communication device 102 determines Yes in this step based on having received a Probe Request from another communication device that has not initiated multilink communication, and proceeds to the process in S703. If the communication device 102 has not received a Probe Request from another communication device, it determines No in this step and proceeds to the process in S708.

[0214] Alternatively, the communication device 102 may make the determination in S707 based on whether it has received an Association Request from another communication device that has not initiated multilink communication. In this case, the communication device 102 determines Yes in this step based on having received an Association Request from another communication device that has not initiated multilink communication, and proceeds to the process in S704. On the other hand, if it has not received an Association Request from another communication device, the communication device 102 determines No in this step and proceeds to the process in S708.

[0215] Furthermore, when communication device 102 receives a change request or Association Request from communication device 103, it returns a change response or Association Response as a response.

[0216] Next, the communication device 102 determines whether to change the link used for multilink 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 proceeds to 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 proceeds to S710. Alternatively, the communication device 102 may make the determination in S708 based on whether or not it has received an Association Request from the communication device 103 in addition to or instead of a change request. If the communication device 103 receives an Association Request from the communication device 102, it determines Yes in this step; otherwise, it determines No.

[0217] Communication device 102 performs a link change process in multilink communication with communication device 103 (S709). Specifically, the link change process involves switching the link used for data communication in multilink communication with communication device 103 to another link already established with communication device 103. In addition to this, or instead, communication device 102 may use another link already established with communication device 103 in addition to the currently used link for data communication with communication device 103. Alternatively, communication device 102 may establish a new link for multilink communication with communication device 103. In this case, communication device 102 may switch the link used for data communication with communication device 103 from the current link to the newly established link, or it may use the newly established link in addition to the current link.

[0218] Communication device 102 initiates multilink communication using a new link with communication device 103.

[0219] Communication device 102 determines whether to terminate multilink communication (S710). Specifically, communication device 102 makes this determination based on whether a link for multilink communication with communication device 103 is maintained. If multiple links are maintained with communication device 103, communication device 102 determines No in this step and proceeds to S706. On the other hand, if multiple links are not maintained with communication device 103, communication device 102 determines Yes in this step and terminates the processing of this flow. Links that are not maintained are links in which identification information was included in the Disassociation frame transmitted from communication device 103, or links in which no communication has taken place for a predetermined time. Alternatively, communication device 102 may determine Yes in S710 if one or more links are maintained with communication device 103, and No if no links are maintained.

[0220] Furthermore, in any step from S705 onward, if communication device 102 receives a Disassociation frame from communication device 103, it will disconnect the link. Specifically, communication device 102 will consider any link in which the Disassociation frame contains identification information to be disconnected and will not perform any communication using that link.

[0221] Furthermore, if the communication device 102 is performing multilink communication with multiple partner devices, the communication device 102 makes the determination in S710 based on the links with all partner devices with which it is performing multilink communication. The communication device 102 determines Yes in S710 if multiple links are maintained with at least one partner device. On the other hand, if multiple links are not maintained with all partner devices, it determines No in S710.

[0222] As shown in Figure 7, after initiating multilink communication with communication device 103, communication device 102 can notify the destination information. By notifying the destination information, communication device 103, having received the information, can change the link in the 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 improve communication efficiency.

[0223] In this embodiment, it is assumed that communication device 103 sends a Probe Request in S706, but this is not limited to this, and other communication devices different from communication devices 102 and 103 may also send a Probe Request to communication device 102. Here, it is assumed that the other communication devices that send the Probe Request have started multilink communication with communication device 102. In this case, communication device 102 may send a Probe Response that includes different destination information for each communication device that sent a Probe Request. For example, communication device 102 may send a Probe Response that includes destination information indicating information about the link established with communication device 103 in response to a Probe Request sent by communication device 103. In this case, the Probe Response sent to communication device 103 does not include destination information regarding the link established with the other communication device. In this case, communication device 102 sends a Probe Response that includes destination information regarding the link established with the other communication device in response to a Probe Request sent by the other communication device. The Probe Response sent to other communication devices does not include destination information regarding the link established with communication device 103.

[0224] Furthermore, if the communication device 102 includes destination information in the Probe Response, it may include only information about the link corresponding to the frequency channel supported by the communication device 103, based on the multilink communication capability information received from the communication device 103.

[0225] Furthermore, in this embodiment, when the communication device 102 transmits migration destination information, it transmits information about all links that could potentially be the migration destination, but this is not limited to this. The communication device 102 may transmit only information about BSSs, frequency channels, or links that it has determined to have a high probability of obtaining a transmission opportunity for the communication device 103 (STA). For example, the communication device 102 determines that a BSS has a high probability of obtaining a transmission opportunity for the STA if the proportion of time the media is busy is small or if there is little high-priority traffic such as AC_VO, AC_VI. The communication device 102 may make similar determinations regarding frequency channels and links. The communication device 102 includes the BSSID of the BSS that has been determined to have a high probability of obtaining a transmission opportunity for the STA in the BSSID field 1123. In this case, other fields of the Link Report may be omitted. Note that the Channel Number field 1126 may be included to indicate the frequency channel used by the relevant BSS. If the determination is based on a number of channels, only the Channel Number field 1126 may be included instead of the BSSID field 1123. Alternatively, the BSSID field 1123 may include an ID of the BSS established by the communication device 102 on the relevant frequency channel. If the determination is based on the link, the BSSID field 1123 may include at least one of the Channel Number field 1126, which indicates the frequency channel used for the link, and the BSSID field 1123, which indicates the BSS. In this case, the communication device 102 selects an appropriate link as the destination for the link transition with the communication device 103 and then transmits information about the candidate link to the communication device 103. This reduces the processing required for the communication device 103 to select the destination link.

[0226] Furthermore, the communication device 102 may include information about multilink communication in the MAC frame when it is performing multilink communication or has been instructed to perform multilink communication, but may not include it otherwise. In particular, when multilink communication is not being performed, frame overhead can be reduced by not including destination information in the Beacon or Probe Response.

[0227] Furthermore, by reusing frame formats defined in standards prior to the IEEE 802.11ax standard when indicating migration destination information, the development burden on software and hardware for configuring or analyzing communication devices can be reduced.

[0228] In this embodiment, when the communication device 102 is performing multilink communication, it includes destination information in at least one of the Beacon and Probe Response. On the other hand, even when the communication device 102 is performing multilink communication, it does not include destination information in the Association Response, Disassociation, Authentication, and De-Authentication. By not including destination information in the frames used when establishing or disconnecting a link, or in the frames used when authenticating the other device, the communication device 102 can reduce frame overhead. Note that the communication device 102 only needs to not include destination information in at least one of the Association Response, Disassociation, Authentication, and 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 obtaining information about other links via a multilink communication link already established with the communication device 102. In this case, changing a link means switching links. Alternatively, the number of links used for data communication may be increased. Or, if data communication with the communication device 102 is already being performed using multiple links, the type of data transmitted over a certain link may be changed, or the proportion of transmitted data may be changed. The communication device 103 obtains information about other links from the communication device 102 via the link to be changed. Alternatively, the communication device 103 may obtain link information from the communication device 102 via a link different from the link to be changed. In this case, the link information may include information about the link used to obtain the information.

[0230] In this embodiment, it is assumed that a Disassociation frame is sent from communication device 103 to communication device 102 when multilink communication is terminated, but this is not limited to this. A Disassociation frame may also be sent from communication device 102 to communication device 103. In this case, communication device 103 executes the process of S710 in Figure 7 instead of S609 and S610 in Figure 6. Similarly, communication device 102 executes the processes of S609 and S610 in Figure 6 instead of S710 in Figure 7.

[0231] Furthermore, in this embodiment, communication devices 102 and 103 established multiple links and communicated migration destination information after starting multilink communication. However, the system is not limited to this, and communication devices 102 and 103 may also communicate migration destination information after establishing a single link. Specifically, instead of multilink communication, communication may be initiated via an established single link at S605 in Figure 6 and S705 in Figure 7. In this case, communication devices 102 and 103 may establish a new link and start multilink communication by changing the link at S608 in Figure 6 and S709 in Figure 7.

[0232] Furthermore, at least part or all of the flowcharts for communication devices 103 and 102 shown in Figures 6 and 7 may be implemented in hardware. When implemented in hardware, for example, a dedicated circuit can be generated on an FPGA from a computer program to implement each step using a predetermined compiler, and this can then be utilized. FPGA stands for Field Programmable Gate Array. Alternatively, a Gate Array circuit may be formed in a similar manner to an FPGA and implemented as hardware. It may also be implemented using an ASIC (Application Specific Integrated Circuit).

[0233] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions. [Explanation of symbols]

[0234] 101 Network 102 Communication equipment (AP) 103 Communication equipment (STA) 104 The first Link 105 The second Link

Claims

1. A communication device capable of performing wireless communication in accordance with the IEEE 802.11 series standard, Communication means for communicating a predetermined MAC (Media Access Control) frame in a first link in a first frequency channel, which includes first information including information about a second link in a second frequency channel and second information including information indicating Capability Information, The system includes establishing means for establishing a first link on the first frequency channel and a second link on the second frequency channel with other communication devices by exchanging Association Request frames and Association Response frames on the first frequency channel with other communication devices, The aforementioned predetermined MAC frame has a header portion and a body portion. In the aforementioned body portion, the first information is arranged after the second information. A communication device characterized by the following features.

2. A communication device capable of performing wireless communication in accordance with the IEEE 802.11 series standard, The communication device includes a communication means for communicating a predetermined MAC frame on a first frequency channel, The system has establishing means for establishing a first link on the first frequency channel and a second link on a second frequency channel different from the first frequency channel with other communication devices through association with other communication devices on the first frequency channel, The aforementioned predetermined MAC frame has a header portion and a body portion, In the body portion, the first information, which includes information relating to the second link in the second frequency channel, is placed after the second information, which includes information indicating Capability Information. A communication device characterized by the following features.

3. In the body portion of the predetermined MAC frame, The first information, which includes information about the second link in the second frequency channel, This information is placed after the third piece of information, which includes information indicating the SSID (Service Set Identifier). A communication device according to claim 1 or 2.

4. The first piece of information is a Multi-Link Element. A communication device according to any one of claims 1 to 3.

5. The information relating to the second link includes an identifier that identifies the second link. A communication device according to any one of claims 1 to 4.

6. The information relating to the second link is stored in a first specific field which contains information relating to the second link. A communication device according to any one of claims 1 to 5.

7. If the communication device is capable of establishing a third link in a third frequency channel with the other communication device, the first information further includes a second specific field, which is different from the first specific field, and which includes information relating to the third link. The communication device according to feature 6.

8. The first specific field containing information relating to the second link includes a Link ID field indicating the identifier of the second link. The communication device according to claim 6 or 7.

9. The first specific field is a Link Info field. A communication device according to any one of claims 6 to 8.

10. The information relating to the second link includes information relating to the capacity of the second link. A communication device according to any one of claims 1 to 9.

11. The information relating to the second link includes information relating to the channel of the second link. A communication device according to any one of claims 1 to 10.

12. The information relating to the second link includes information relating to the maximum number of streams supported by the second link. A communication device according to any one of claims 1 to 11.

13. The first information includes information regarding the maximum number of links that can operate simultaneously. A communication device according to any one of claims 1 to 12.

14. The information of the above-mentioned 1 is further, This includes information indicating whether or not it supports simultaneous transmission of data on the first link and reception of data on the second link. A communication device according to any one of claims 1 to 13.

15. The first information further includes, Includes Element ID field and Length field A communication device according to any one of claims 1 to 14.

16. The establishing means establishes a first link in the first frequency channel and a second link in the second frequency channel with the other communication device by communicating an Association Request frame and an Association Response frame with the other communication device in the first frequency channel, The Association Request frame and the Association Response frame each contain the first information. A communication device according to any one of claims 1 to 15.

17. The same SSID is set for the first link and the second link. A communication device according to any one of claims 1 to 16.

18. The communication device communicates using at least one of the following frequency bands: 2.4 GHz band, 5 GHz band, 6 GHz band, and 60 GHz band. A communication device according to any one of claims 1 to 17.

19. The communication device communicates using at least one bandwidth from among 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz. A communication device according to any one of claims 1 to 18.

20. The communication device has a plurality of antennas A communication device according to any one of claims 1 to 19.

21. The communication device is capable of performing communication using OFDMA (Orthogonal Frequency Division Multiple Access). A communication device according to any one of claims 1 to 20.

22. The communication device is capable of simultaneously transmitting data on the first link and receiving data on the second link. A communication device according to any one of claims 1 to 21.

23. When the communication device transmits data on the first link, it is possible to simultaneously transmit only data on the second link. A communication device according to any one of claims 1 to 21.

24. When the communication device receives data on the first link, it is possible to simultaneously receive only data on the second link. A communication device according to any one of claims 1 to 21.

25. The data transmitted in the first link and the data transmitted in the second link are the same data. A communication device according to any one of claims 1 to 24.

26. The predetermined MAC frame is a Beacon frame or a Probe Response frame. A communication device according to any one of claims 1 to 25.

27. A control method for a communication device capable of performing wireless communication in accordance with the IEEE 802.11 series standard, A communication step of communicating a predetermined MAC frame in a first link in a first frequency channel, which includes first information including information about a second link in a second frequency channel and second information including information indicating Capability Information, The system includes an establishment step of establishing a first link on the first frequency channel and a second link on the second frequency channel with other communication devices by exchanging Association Request frames and Association Response frames on the first frequency channel with other communication devices, The aforementioned predetermined MAC frame has a header portion and a body portion. In the aforementioned body portion, the first information is arranged after the second information. A method for controlling a communication device, characterized by the features described above.

28. A method for controlling a communication device capable of performing wireless communication in accordance with the IEEE 802.11 series standards, The control method includes a communication step of communicating a predetermined MAC frame on a first frequency channel, The system includes an establishment step of establishing a first link on the first frequency channel and a second link on a second frequency channel different from the first frequency channel with other communication devices through association with other communication devices on the first frequency channel, The aforementioned predetermined MAC frame has a header portion and a body portion, In the body portion, the first information, which includes information relating to the second link in the second frequency channel, is placed after the second information, which includes information indicating Capability Information. A method for controlling a communication device, characterized by the features described above.

29. A program for operating a computer as a communication device according to any one of claims 1 to 26.

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