Communication device, control method, and program

Abstract

To reduce the overhead of communication when transmitting capability information about communication performed by establishing multiple links with other communication devices.SOLUTION: An AP 102 receives a Probe Request frame from another communication device, for example, an STA 103 and transmits a Probe Response frame to the STA 103 containing the Capability information of the multi-link communication corresponding to a frequency band or a frequency channel determined on the basis of information about the frequency band or frequency channel contained in the received Probe Request frame.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 established by IEEE (Institute of Electrical and Electronics Engineers), the IEEE 802.11 series is known. Note that WLAN is an abbreviation for Wireless Local Area Network. The IEEE 802.11 series standards include standards such as IEEE 802.11a / b / g / n / ac / ax standards.

[0003] Patent Document 1 discloses that in the IEEE 802.11ax standard, wireless communication by OFDMA (Orthogonal Frequency Division Multiple Access) is performed. In the IEEE 802.11ax standard, high peak throughput is realized by performing wireless communication by OFDMA.

[0004] IEEE is considering formulating the IEEE 802.11be standard as a new standard for the IEEE 802.11 series in order to further improve throughput and frequency utilization efficiency. In the IEEE 802.11be standard, a technique in which one AP (Access Point) establishes and communicates with one STA (Station) through a plurality of different frequency channels and a plurality of links is being studied.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] When APs and STAs establish multiple links and communicate with each other, they use ProbeRequest and ProbeResponse frames to communicate capability information. However, if the AP notifies the STA of capability information for all frequency bands or frequency channels on which it can establish links, the frame size increases, resulting in significant communication overhead.

[0007] In view of the above issues, the present invention aims to reduce the communication overhead when transmitting capability information related to communication that is performed by establishing multiple links with other communication devices. [Means for solving the problem]

[0008] To achieve the above objective, the communication device of the present invention is P A receiving means for receiving a robe Request frame from another communication device, and the receiving means The Includes 1 Multi-Link element P When a robe Request frame is received , including information corresponding to the unique information for each link included in the first Multi-Link element The Probe Response frame containing the second Multi-Link element sending believe First Transmission means and When the receiving means receives a Probe Request frame that does not contain the first Multi-Link element, a second transmitting means transmits a Probe Response frame that does not contain the information, to have vinegar ru. [Effects of the Invention]

[0009] According to the present invention, the communication overhead is reduced when transmitting capability information related to communication that is performed by establishing multiple links with other communication devices. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows the network configuration to which AP102 belongs. [Figure 2]This diagram shows the hardware configuration of AP102. [Figure 3] This diagram shows the functional configuration of AP102. [Figure 4] This sequence diagram shows an example of the process that AP102 executes when it notifies STA103 of capability information. [Figure 5] This figure shows an example of the frame structure of a Probe Request frame. [Figure 6] This figure shows an example of the frame structure of a Probe Response frame. [Figure 7] This flowchart shows the process that AP102 executes when it notifies of capability information. [Figure 8] This sequence diagram shows another example of the process that AP102 performs when notifying STA103 of capability information. [Figure 9] This flowchart shows another process that AP102 performs when it notifies Capability information. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described in detail below with reference to the attached 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] <Embodiment 1> Figure 1 shows the network configuration in which the AP (Access Point) 102 according to this embodiment participates. AP 102 is a communication device that plays a role in constructing network 101. STA (Station) 103 is a communication device that plays a role in participating in network 101 constructed by the access point. Each communication device complies with the IEEE 802.11be (EHT) standard and can perform wireless communication compliant with the IEEE 802.11be standard via network 101. IEEE stands for Institute of Electrical and Electronics Engineers. EHT stands for Extremely High Throughput. EHT may also be interpreted as an abbreviation for Extreme High Throughput. Each communication device can communicate in the 2.4GHz, 5GHz, and 6GHz frequency bands. The frequency band used by each communication device is not limited to these; for example, a different frequency band such as the 60GHz band may be used. Furthermore, each communication device can communicate using bandwidths of 20MHz, 40MHz, 80MHz, 160MHz, and 320MHz.

[0013] AP102 and STA103 perform Multi-Link communication that establishes and communicates over a plurality of frequency channels. Here, a frequency channel refers to a frequency channel defined in the IEEE802.11 series of standards and capable of performing wireless communication compliant with the IEEE802.11 series of standards. In the IEEE802.11 series of standards, a plurality of frequency channels are defined in each of the 2.4GHz band, 5GHz band, and 6GHz band. Also, in the IEEE802.11 series of standards, the bandwidth of each frequency channel is defined as 20MHz. Note that by bonding with an adjacent frequency channel, a bandwidth of 40MHz or more may be utilized in one frequency channel. For example, AP102 can establish a first link 104 via a first frequency channel in the 2.4GHz band with STA103 and a second link 105 via a second frequency channel in the 5GHz band and communicate via both links. In this case, AP102 maintains the second link 105 via the second frequency channel in parallel with the first link 104 via the first frequency channel. Thus, by establishing links with STA103 via a plurality of frequency channels, AP102 can improve the throughput in communication with STA103.

[0014] Furthermore, AP102 and STA103 may establish multiple links in different frequency bands in multilink communication. For example, AP102 and STA103 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 within the same frequency band. For example, a first link 104 may be established via channel 1 in the 2.4GHz band, and a second link 105 may be established via channel 5 in the 2.4GHz band. Furthermore, links in the same frequency band and links in different frequency bands may be mixed. For example, AP102 and STA103 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. AP102 can establish multiple connections with STA103 using different frequency bands, allowing it to communicate with STA103 on other bands even when one band is congested, thus preventing a decrease in throughput during communication with STA103.

[0015] The AP102 and STA103 can perform multilink communication in three modes. One is Asynchronous Mode (Async Mode), in which communication through each link in multilink communication is performed asynchronously. Specifically, communication through the first link and communication through the second link are performed at independent timings. Therefore, both the first and second links can communicate at timings that are not affected by the timing of communication on the other link.

[0016] Another mode is the Synchronous Mode (Sync Mode). In this mode, communication via multiple links is executed synchronously. Specifically, communication starts at the same timing on the first link and the second link. In this case, since communication via each link starts simultaneously, the other link does not perform carrier sensing on the communication of one link.

[0017] Also, another mode is the Semi-Asynchronous Mode (Semi-Async Mode). In this mode, when communicating data via one link, if the frequency channel of the other link is idle, it is a mode where communication via both links is executed synchronously. For example, when the backoff counter of the first link reaches 0 and the frequency channel of the second link is idle, communication via the first link and the second link starts at the same timing. In this case, the backoff counter of the second link does not have to be 0. Note that when the backoff counter of the first link reaches 0 and the frequency channel of the second link is not idle, only communication via the first link is started, and communication via the second link is not started.

[0018] AP102 and STA103 only need to correspond to at least one of the above three modes as the multi-link communication mode. Also, when corresponding to multiple modes, at least one of AP102 and STA103 selects which mode to execute the multi-link according to user instructions, instructions from the application, or communication status, etc.

[0019] While AP102 and STA103 are stated to be compatible with the IEEE 802.11be standard, they may also be compatible with at least one of the legacy standards that predate 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 standards, they may also be compatible 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.

[0020] Specific examples of AP102 include, but are not limited to, wireless LAN routers and PCs. AP102 can be any communication device capable of performing multilink communication with other communication devices. AP102 may also be an information processing device such as a wireless chip capable of performing wireless communication compliant with the IEEE 802.11be standard. Specific examples of STA103 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, and video cameras. STA103 can be any communication device capable of performing multilink communication with other communication devices. STA103 may also be an information processing device such as a wireless chip capable of performing wireless communication compliant with the IEEE 802.11be standard. The network in Figure 1 consists of one AP and one STA, but the number of APs and STAs is not limited to this. Information processing devices such as wireless chips may also have antennas for transmitting the generated signals.

[0021] Figure 2 shows the hardware configuration of AP102 in this embodiment. AP102 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.

[0022] 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.

[0023] The control unit 202 is composed of one or more processors, such as a CPU and an MPU, and controls the entire AP102 by executing a computer program stored in the memory unit 201. Alternatively, the control unit 202 may control the entire AP102 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 AP102 may be controlled by these multiple processors.

[0024] 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 AP102 to perform predetermined processes.

[0025] 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 from the 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 AP102 or may be separate components.

[0026] 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, as well as 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 AP102 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 AP102 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 AP102 communicates data such as image data, document data, and video data with the STA103 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.

[0027] Antenna 207 is an antenna capable of communication in the 2.4GHz, 5GHz, and 6GHz bands. In this embodiment, AP102 is assumed to have one antenna, but it may have different antennas for each frequency band. Also, if AP102 has multiple antennas, it may have a communication unit 206 corresponding to each antenna.

[0028] The STA103 has the same hardware configuration as the AP102.

[0029] Figure 3 shows the functional configuration of AP102 in this embodiment. AP102 consists of a Probe Request frame analysis unit 301, a Probe Response frame generation unit 302, a channel information management unit 303, and a data transmission / reception unit 304.

[0030] The Probe Request frame analysis unit 301 is a block that analyzes the Probe Request frame received from the STA103. The Probe Request frame is one of the management frames compliant with the IEEE 802.11 series standard and is a frame that requests network information. In this embodiment, the Probe Request frame includes information indicating whether the STA103 supports multilink communication and information regarding the frequency channels that support communication.

[0031] The Probe Response frame generation unit 302 is a block that generates Probe Response frames to be transmitted by AP102. A Probe Response frame is one of the management frames compliant with the IEEE 802.11 series standard, and is a frame that provides network information and is transmitted as a response to a Probe Request frame. In this embodiment, the Probe Response frame includes capability information regarding multilink communication of AP102. In this embodiment, the Probe Response frame generation unit 302 generates a frame that includes information on multilink communication corresponding to the frequency channels that STA103 supports, as indicated by the received Probe Request frame. In this case, communication overhead can be reduced by not including information on multilink communication corresponding to frequency channels that AP102 supports but STA103 does not.

[0032] The channel information management unit 303 is a block that manages information about the frequency channels in the multilink communication supported by AP102. Specifically, the channel information management unit 303 manages information about at least one of the frequency channels on which AP102 is performing multilink communication and the frequency channels on which AP102 is capable of performing multilink communication.

[0033] The data transmission / reception unit 304 is a block that transmits and receives management frames and data frames according to the IEEE 802.11 series standard.

[0034] Figure 4 shows a sequence diagram illustrating an example of the process performed when AP102 notifies STA103 of Capability information. This sequence begins when the power to AP102 and STA103 is turned on. Alternatively, it may begin when at least one of AP102 and STA103 is instructed by a user or application to start multilink communication. Alternatively, it may begin when at least one of AP102 and STA103 has reached a predetermined threshold amount of data to be communicated with the other device.

[0035] In this embodiment, AP102 supports multilink communication using up to three links and internally has connection processing units corresponding to each of the multiple links. Specifically, AP102 has connection processing units for AP1 to AP3, each using a different frequency band. On the other hand, STA103 supports multilink communication using up to two links and internally has connection processing units for STA1 to STA2, each using a different frequency band. Furthermore, STA103 does not support wireless communication in the 6GHz band.

[0036] STA1, operating in the 2.4GHz band within STA103, sends a Probe Request frame to request multilink communication capability information from AP102 (S401). In this case, STA103 may send a Probe Request frame in this step based on having received a Beacon frame (not shown) from AP102 prior to S401.

[0037] In this case, the Probe Request frame transmitted by STA103 includes an ML (Multi-Link) element and channel information indicating at least one of the frequency channels or frequency bands supported by STA103. The ML element is information indicating that STA103 supports multi-link communication. In this embodiment, since STA103 supports wireless communication in the 2.4GHz and 5GHz bands, the channel information includes information indicating that it supports the 2.4GHz and 5GHz bands.

[0038] In this embodiment, the Probe Request frame is assumed to contain channel information separately from the ML element, but this is not limited to this, and the channel information may also be included within the ML element.

[0039] AP102 transmits a Probe Response frame (S402) containing capability information determined based on the channel information of STA103 included in the received Probe Request frame. AP102 compares the channel information indicating the frequency channels or frequency bands that its device supports for multilink communication with the channel information of STA103. Then, AP102 includes only the capability information for the frequency bands or channels supported by STA103 in the Probe Response frame. In Figure 4, since STA103 supports only the 2.4GHz and 5GHz bands, AP102 transmits a Probe Response frame containing capability information for the 2.4GHz and 5GHz bands. In this case, the transmitted Probe Response frame does not include capability information for the 6GHz band. This reduces the amount of information included in the Probe Response frame, thereby reducing communication overhead.

[0040] In this embodiment, STA103 does not support wireless communication in the 6GHz band. However, this is not limited to this embodiment; wireless communication in the 6GHz band may be possible, but multilink communication may not be supported. In this case, AP102 determines the capability information to be included in the Probe Response frame to be transmitted based on the channel information contained in the received ML element.

[0041] Furthermore, in this embodiment, the channel information includes information indicating the frequency band supported by STA103, but in addition to this, or instead, information indicating the frequency channels supported by STA103 may also be included. In this case, AP102 may send a Probe Response frame that includes only capability information regarding the frequency channels supported by STA103. For example, suppose STA103 sends a Probe Request frame that includes information indicating channels 1 to 5 in the 2.4GHz band as channel information. In this case, AP102 may send a Probe Response frame that includes capability information for channels 1 to 5, but does not include capability information for channels 6 to 13.

[0042] Furthermore, AP1 to AP3 may be configured as independent hardware components, or they may be configured as software components. The same applies to STA1 to STA2.

[0043] Figure 5 shows an example of the frame structure of a Probe Request frame. In this embodiment, the Probe Request frame is composed of the following fields: SSID element 501, Supported Rates Element 502, and HT Capabilities element 504. HT stands for High Throughput. Furthermore, the Probe Request frame is composed of the following fields: VHT (Very High Throughput) Capabilities element 505 and ML element 506. Furthermore, the Probe Request frame is composed of the following fields: Multi-band element 507 and Supported Operating element 508.

[0044] STA103 transmits the SSID element 501 first, followed by each field shown in Figure 5, from left to right. STA103 may begin transmitting the Probe Request frame only after all fields included in the Probe Request frame have been generated. Alternatively, STA103 may begin transmitting after some fields have been generated, and then generate the remaining fields and transmit the fields that have been generated in parallel.

[0045] The Probe Request frame does not need to include all the fields shown in Figure 5; at least one field may be omitted.

[0046] SSID element501 is a field that specifies the SSID of AP102 from which STA103 requests Capability information.

[0047] Supported Rates Element502 is a field that lists the data rates supported by STA103.

[0048] Field 503, transmitted after Supported Rates Element 502, includes a field indicating the capability information of STA103 on the channel from which STA103 is transmitting Probe Request frames. In this embodiment, field 503 specifically includes, but is not limited to, HT Capabilities element 504 and VHT Capabilities element 505.

[0049] HT Capabilities element 504 is a field that indicates the capability information of STA103 when performing communication compliant with the IEEE 802.11n standard.

[0050] The VHT Capabilities element 505 is a field that indicates the capability information of STA103 when performing communication compliant with the IEEE 802.11ac standard.

[0051] In addition, field 503 may include an EHT Capabilities element instead of, or in addition to, HT Capabilities element 504 and VHT Capabilities element 505. The EHT Capabilities element is a field that indicates the capability information of STA103 when performing communication compliant with the IEEE 802.11be standard.

[0052] The ML (Multi-Link) element 506 is a field that indicates capability information for multi-link communication in the STA103. If the Probe Request frame contains ML element 506, it indicates that the STA103 supports multi-link communication.

[0053] Note that Probe Request frames sent by STAs that do not support multilink communication do not include ML elements.

[0054] Like other Information Elements defined in the IEEE 802.11 series standards, ML element 506 includes an Element ID field 511 and a Length field 512. Furthermore, ML element 506 includes fields for element-specific information. These fields include Common Info 513, which contains information common to all links, and field 514, which includes one or more Per Link Info 515 fields, which contain information specific to each link.

[0055] In this embodiment, the ML element 506 includes information about frequency channels on which STA103 has already established a link with other communication devices, and / or information about frequency channels on which STA103 can perform multilink communication.

[0056] The Element ID field 511 is a field that contains information that identifies the Element.

[0057] The Length field 512 is a field that contains information indicating the data length of the Element.

[0058] Per Link Info515 is further composed of subfields 521 to 524.

[0059] Band ID 521 is a subfield that contains information identifying the frequency band. Specifically, it contains a value indicating the frequency band, as shown in Table 1.

[0060] [Table 1]

[0061] Supported Bandwidth522 is a subfield that contains information indicating the bandwidth that the STA103 supports during multilink communication in the frequency band indicated by Band ID521. Specifically, it contains a value indicating the bandwidth, as shown in Table 2.

[0062] [Table 2]

[0063] Supported CH(Channel)523 is a subfield containing information indicating the channels on which STA103 can perform multilink communication in the frequency band indicated by Band ID521. Alternatively, this subfield may also include information indicating channels on which STA103 has already established a link. For example, if Band ID521 contains information indicating the 2.4GHz band, it will contain channel values ​​as shown in Table 3. Note that this subfield may contain information indicating only one frequency channel or information indicating multiple frequency channels.

[0064] [Table 3]

[0065] Supported Nss524 is a subfield that contains information indicating the maximum number of MIMO streams that the STA103 supports during multilink communication in the frequency band indicated by Band ID 521.

[0066] Per Link Info 515 may include all or some of the subfields 521-524. For example, Per Link Info 515 may be configured to include Band ID 521 but not Supported CH 523.

[0067] Furthermore, the ML element 506 may be configured to include one Per Link Info 515 for each frequency band, or one Per Link Info 515 for each frequency channel.

[0068] The Multi-Band element 507 is a field containing information indicating the frequency bands and channels supported by the STA103. When the Multi-Band element 507 is included in a Probe Request frame, it indicates that the STA103 supports communication across multiple frequency bands. The ML element 506 was a field containing information indicating the frequency bands and channels on which the STA103 can perform multilink communication. However, this field now includes information indicating the frequency bands and channels on which the STA103 can perform wireless communication, not limited to multilink communication.

[0069] The Multi-Band element 507 includes a Band ID, which contains information indicating the frequency band on which STA103 can perform wireless communication. Furthermore, this element includes Operating classes, which contain information indicating the frequency channels within the frequency band indicated by the Band ID on which STA103 can perform wireless communication. The Operating classes also contain information indicating a set of multiple frequency channels on which STA103 can perform wireless communication. Note that the Multi-Band element 507 may contain only either the Band ID or the Operating classes.

[0070] The Supported Operating element 508 is a field that contains information indicating the frequency channels supported by STA103 in each country. Specifically, it contains information indicating the frequency channels supported by STA103 in the countries where STA103 is currently located. This field contains numerical information that can identify one or more sets of frequency channels and frequency bands.

[0071] Multi-Band element 507 and Supported Operating element 508 are both pieces of information defined in standards prior to the IEEE 802.11ax standard.

[0072] In this embodiment, STA103 includes at least one of the Multi-Band element 507 or the Supported Operating element 508 as channel information. Alternatively, STA103 may use the Per Link Info 515 included in the ML element 506 as channel information in addition to or instead of the above. Furthermore, when using Per Link Info 515 as channel information, it may be configured to include only one of the Band ID 521 and Supported CH 523, or to include both.

[0073] STA103 can notify AP102 of the frequency band and / or frequency channel on which it can communicate by sending a Probe Request frame containing channel information to AP102. Additionally, STA103 can notify AP102 that it supports multilink communication by sending a Probe Request frame containing an ML element 506.

[0074] Note that the names of the fields shown in Figure 5, as well as the order of transmission and generation, are not limited to these. Similar information may be included in fields with different names, and may be transmitted or generated in different orders. Furthermore, any of the fields or subfields shown in Figure 5 may be omitted.

[0075] Figure 6 shows an example of the frame structure of a Probe Response frame. In this embodiment, the Probe Response frame is composed of the fields SSID element 601, Supported Rates Element 602, and HT Capabilities element 604. Furthermore, the Probe Response frame is composed of the fields VHT Capabilities element 605 and ML element 606. Furthermore, the Probe Response frame is composed of the fields Multi-band element 607 and Supported Operating element 608.

[0076] AP102 transmits the SSID element 601 first, followed by each field shown in Figure 6, from left to right. AP102 may start transmitting the Probe Response frame only after all fields included in the Probe Response frame have been generated. Alternatively, AP102 may start transmitting after some fields have been generated, and generate the remaining fields and transmit the fields that have been generated in parallel.

[0077] Fields 601-624 in Figure 6 contain the same information as fields 501-524 in Figure 5. Note that while fields 501-524 in Figure 5 contain information indicating the capability of STA103, fields 601-624 in Figure 6 contain information indicating the capability of AP102.

[0078] Furthermore, the Probe Response frame may include a field 625 in Per Link Info 615 that shows capability information for the frequency band indicated by AP102's Band ID 621. Alternatively, field 625 may include information showing AP102's capability information for the frequency channel indicated by Supported CH 623.

[0079] Specifically, field 625 is configured to include HT Capabilities element 626 and VHT Capabilities element 627. Each field contains information similar to that of fields 504 and 505 shown in Figure 5. In addition to, or instead of, these fields, an EHT Capabilities element field may also be included.

[0080] AP102 determines which channel information to include in the Probe Response frame based on the channel information of STA103 contained in the Probe Request frame received from STA103. AP102 decides to include only the capability information related to the frequency band and / or frequency channel indicated by the channel information received from STA103 in the Probe Response frame. Specifically, AP102 includes only the Per Link Info corresponding to the frequency band and / or frequency channel indicated by the channel information contained in the Probe Request frame received from STA103 in the ML element 606. By not including capability information related to frequency bands and frequency channels that STA103 does not support in the Probe Response frame, AP102 can reduce communication overhead.

[0081] Note that the names of the fields shown in Figure 6, as well as the order of transmission and generation, are not limited to these. Similar information may be included in fields with different names, and may be transmitted or generated in different orders. Furthermore, any of the fields or subfields shown in Figure 6 may be omitted.

[0082] Figure 7 is a flowchart showing the process that occurs when AP102 notifies Capability information, by the control unit 202 reading and executing a computer program stored in the memory unit 201. The process in this flowchart starts when at least one of AP1 to AP3, the connection processing units of AP102, receives a Probe Request frame from STA. AP1 to AP3 may each execute the process in this flowchart independently and in parallel.

[0083] AP102 determines whether the Probe Request frame received from STA103 contains an ML element (S700). If the received Probe Request frame contains an ML element, AP102 determines "Yes" in this step and proceeds to S702. On the other hand, if the Probe Request frame does not contain an ML element, AP102 determines "No" in this step and proceeds to S701.

[0084] If the received Probe Request frame does not contain an ML element, AP102 generates a Probe Response frame that does not contain an ML element (S701). Specifically, it generates a Probe Response frame that does not contain ML element 606 as shown in Figure 6. Because this Probe Response frame does not contain an ML element, it is backward compatible with IEEE 802.11 series standards prior to the IEEE 802.11ax standard. AP102 determines that STA103 does not support multilink communication because the received Probe Request frame does not contain an ML element. After performing the processing in this step, AP102 performs the processing in S709.

[0085] If S700 determines Yes, AP102 determines whether the received Probe Request frame contains information indicating the frequency channel (S702). In this case, since the received Probe Request frame contains an ML element, AP102 determines that STA103 supports multilink communication. Specifically, the information indicating the frequency channel is the information containing the Supported CH523 in the Per Link Info shown in Figure 5. Alternatively, it may be the information indicating the frequency channel contained in the Operating classes within the Multi-Band element 507. Or, it may be the information indicating the frequency channel contained in the Supported Operating element 508. If the received Probe Request frame does not contain information indicating the frequency channel, AP102 determines No in this step and proceeds to S704. On the other hand, if the Probe Request frame contains information indicating the frequency channel, AP102 determines Yes in this step and proceeds to S703.

[0086] AP102 generates a Probe Response frame containing capability information corresponding to the frequency channel specified by the frequency channel information contained in the received Probe Request frame (S703). Specifically, it generates a Probe Response frame containing an ML element 606 that includes only the Per Link Info 615 containing the Supported CH 523 corresponding to the specified frequency channel. After performing the processing in this step, AP102 performs the processing in S709.

[0087] In this embodiment, AP102 generates a Probe Response frame in S703 that contains only the capability information corresponding to the specified frequency channel, but this is not limited to this. AP102 may also generate a Probe Response frame that contains only the capability information corresponding to the frequency band to which the specified frequency channel belongs. Even in this case, the Probe Response frame does not contain capability information corresponding to frequency bands to which the specified frequency channel does not belong, thus reducing communication overhead.

[0088] If the result in S702 is No, AP102 determines whether the received Probe Request frame contains information indicating the frequency band (S704). Specifically, the information indicating the frequency band is the information containing BandID521 in Per Link Info515 shown in Figure 5. Alternatively, it may be the information indicating the frequency band contained in Band ID in Multi-Bandelement507. Alternatively, it may be the information indicating the frequency band contained in Supported Operating element508. If the received Probe Request frame does not contain information indicating the frequency band, AP102 determines No in this step and proceeds to process S707. On the other hand, if the Probe Request frame contains information indicating the frequency band, AP102 determines Yes in this step and proceeds to process S705.

[0089] AP102 generates a Probe Response frame containing Capability information corresponding to the frequency band specified by the information indicating the frequency band included in the received Probe Request frame (S705). Specifically, it generates a Probe Response frame containing an ML element 606 that includes only the Per Link Info 615 containing the Band ID 521 corresponding to the specified frequency band. After performing the processing in this step, AP102 performs the processing in S709.

[0090] If S704 determines No, AP102 generates a ProbeResponse frame containing Capability information corresponding to all frequency bands and / or frequency channels supported by its device (S707). Specifically, AP102 generates a Probe Response frame containing an ML element 606 that includes Per Link Info 615 corresponding to all frequency bands and / or frequency channels on which its device can perform multilink communication. After completing the processing in this step, AP102 proceeds with the processing in S709.

[0091] AP102 sends the generated Probe Response frame to STA103, the source of the received Probe Request frame (S709).

[0092] As shown in Figure 7, AP102 can reduce communication overhead by determining the capability information to include in the Probe Response frame based on the information contained in the received Probe Request frame. Furthermore, if STA103 does not support multilink communication, communication overhead can be further reduced by not including the ML element in the Probe Response frame.

[0093] Furthermore, if AP102 has already established links that are experiencing high communication load and should not be used for communication with STA103, it may generate a Probe Response frame excluding the Capability information corresponding to those links. High communication load occurs, for example, when the amount of data transmitted on the link within a predetermined time exceeds a predetermined threshold. Alternatively, it occurs when the amount of data that fails to communicate on the link within a predetermined time exceeds a predetermined threshold. Or, it occurs when the received signal strength from other communication devices via the link falls below a predetermined threshold. By excluding the Capability information of links to be excluded from communication with STA103 from the Probe Response frame in this way, AP102 can further reduce communication overhead.

[0094] <Embodiment 2> Embodiment 1 described the processing that AP102 performs when it receives a Probe Request frame from STA103 via one frequency channel. Embodiment 2 describes the processing that AP102 performs when it receives a Probe Request frame from STA103 via two or more frequency channels.

[0095] The network configuration of the network in which AP102 participates is the same as in Figure 1 of Embodiment 1. The hardware configuration of AP102 is the same as in Figure 2 of Embodiment 1. The functional configuration of AP102 is the same as in Figure 3 of Embodiment 1. The frame configuration of the Probe Request frame is the same as in Figure 5. The frame configuration of the Probe Response frame is the same as in Figure 6. Here, only the differences from Embodiment 1 will be explained.

[0096] Figure 8 shows a sequence diagram illustrating another example of the process performed when AP102 notifies STA103 of Capability information. This sequence begins when the power to AP102 and STA103 is turned on. Alternatively, it may begin when at least one of AP102 and STA103 is instructed by a user or application to start multilink communication. Alternatively, it may begin when at least one of AP102 and STA103 has reached a predetermined threshold amount of data to be communicated with the other device.

[0097] AP102 and STA103 each support multilink communication as shown in Figure 4 of Embodiment 1, and internally have connection processing units corresponding to each of the multiple links. AP1 to AP3 may be configured as independent hardware or as software. The same applies to STA1 to STA2.

[0098] STA1, operating in the 2.4GHz band within STA103, sends a Probe Request frame to request multilink communication capability information from AP102 (S801). In this case, STA103 may send a Probe Request frame in this step based on having received a Beacon frame (not shown) from AP102 prior to S801.

[0099] In this case, the Probe Request frame transmitted by STA103 includes an ML element and channel information indicating at least one of the frequency channels or frequency bands supported by STA103. In this embodiment, since STA103 supports wireless communication in the 2.4GHz and 5GHz bands, the channel information includes information indicating that it supports the 2.4GHz and 5GHz bands.

[0100] In this embodiment, the Probe Request frame is assumed to contain channel information separately from the ML element, but this is not limited to this, and the channel information may also be included within the ML element.

[0101] Next, STA2, which operates in the 5GHz band within STA103, sends a Probe Request frame requesting AP102's multilink communication capability information (S802). This can occur, for example, if communication is temporarily congested on the frequency channel used by STA1, and AP102 is unable to send a Probe Response frame for a certain period of time. If STA103 does not receive a response after a certain period of time has elapsed since sending the Probe Request frame via STA1, it may send another Probe Request frame via STA2, which uses a different frequency band. The Probe Request frame sent in this step, like the Probe Request frame sent in S801, includes information indicating support for both the 2.4GHz and 5GHz bands as channel information.

[0102] If AP102 receives a Probe Request frame from STA103 via multiple frequency channels, it only needs to send a Probe Response frame to STA103 via any one of the frequency channels. In this sequence, AP2, which operates in the 5GHz band within AP102, sends a Probe Response frame to STA103 (S803). The Probe Response frame sent in this step includes capability information determined based on the channel information of STA103 contained in the Probe Request frame received by AP102, similar to S402 in Figure 4. Alternatively, AP1, which operates in the 2.4GHz band and received the Probe Request frame earlier, may send the Probe Response frame instead of AP2, which operates in the 5GHz band and received the Probe Request frame later. Furthermore, AP102 may receive three or more Probe Request frames from STA103.

[0103] As shown in Figure 8, even if AP102 receives Probe Request frames from the same STA via two or more frequency channels, it will only send a Probe Response frame via one frequency channel. This prevents AP102 from sending multiple Probe Response frames with the same content, thus preventing an increase in communication overhead.

[0104] Figure 9 is a flowchart showing another process that is executed when AP102 notifies Capability information, by the control unit 202 reading and executing a computer program stored in the memory unit 201. The process in this flowchart is started when at least one of AP1 to AP3, the connection processing units of AP102, receives a Probe Request frame from STA. AP1 to AP3 may each execute the process in this flowchart independently and in parallel.

[0105] When AP102 receives a Probe Request frame from STA103, it sets a flag to 1 to indicate that it is processing the Probe Request frame for the received link (S900).

[0106] For S901 to S909, the same processing as S700 to S707 in Figure 7 of Embodiment 1 is performed.

[0107] When AP102 generates a Probe Response frame to send, it determines whether a flag indicating that it is processing Probe Request frames for other links is set to 1 (S910). Specifically, it determines whether the flag is set for a link different from the one flagged in S900. If the flag is not set for other links, AP102 determines No in this step and proceeds to S911. On the other hand, if the flag is set for other links, AP102 determines Yes in this step and proceeds to S913.

[0108] AP102 determines in S910 whether the source of the Probe Request frame received on the link flagged in S900 is the same as the source of the Probe Request frame received on another link that was flagged in S910 (S913). Specifically, AP102 compares the source identification information contained in the received Probe Request frame. If they match, it determines Yes in this step and proceeds to S912. On the other hand, if the source identification information does not match, AP102 determines No in this step and proceeds to S911.

[0109] AP102 sends the generated Probe Response frame to the source STA of the Probe Request frame received in S900 (S911). After processing S911, AP102 performs the processing in S912.

[0110] AP102 sets a flag to 0 to indicate that it is processing the Probe Request frame for the received link (S912). After processing S912, AP102 terminates processing this flow.

[0111] As shown in Figure 9, even if AP102 receives Probe Request frames from the same STA via multiple frequency channels, it will only send a Probe Response frame via one frequency channel. This prevents AP102 from sending multiple Probe Response frames containing the same capability information, thus preventing an increase in communication overhead.

[0112] Although the processes shown in Embodiment 1 and Embodiment 2 are assumed to be executed by different APs, this is not limited to a single AP. In this case, the AP has a mode for executing the processes of Embodiment 1 and a mode for executing the processes of Embodiment 2. Such an AP may switch between operating in the mode for executing the processes shown in each embodiment based on user instructions or based on application instructions.

[0113] Furthermore, at least part or all of the AP102 flowcharts shown in Figures 7 and 9 may be implemented in hardware. When implemented in hardware, for example, a dedicated circuit can be generated on the 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).

[0114] 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]

[0115] 101 Network 102 AP 103 STA 104 The first link 105 Second Link

Claims

1. A communication device, A receiving means for receiving Probe Request frames from other communication devices, When the receiving means receives a Probe Request frame containing a first Multi-Link element, the first transmitting means transmits a Probe Response frame containing a second Multi-Link element containing information corresponding to the unique information for each link contained in the first Multi-Link element, When the receiving means receives a Probe Request frame that does not contain the first Multi-Link element, a second transmitting means transmits a Probe Response frame that does not contain the information, A communication device characterized by having the following features.

2. The second Multi-Link element of the Probe Response frame transmitted by the first transmitting means contains only the information corresponding to the unique information for each link included in the first Multi-Link element of the Probe Request frame received by the receiving means. The communication device according to feature 1.

3. When the receiving means receives a Probe Request frame including a first Multi-Link element that does not include unique information for each link, the communication device further comprises a third transmitting means that transmits a Probe Response frame to a second Multi-Link element that includes the information corresponding to all links supported by the communication device. A communication device according to claim 1 or 2.

4. The receiving means further comprises a determination means for determining which information to include in the second Multi-Link element of the Probe Response frame transmitted by the first transmitting means, based on predetermined identification information contained in the unique information for each link contained in the first Multi-Link element received by the receiving means. A communication device according to any one of claims 1 to 3.

5. The aforementioned predetermined identification information is included in the Band ID field. The communication device according to feature 4.

6. The first Multi-Link element and the second Multi-Link element each include a first field and a second field. The first field is a Common Info field containing information common to all links, and the second field contains unique information for one or more links. A communication device according to any one of claims 1 to 5, characterized by the features described herein.

7. The unique information for each link is contained in the Per Link Info field for each link. A communication device according to any one of claims 1 to 6, characterized by...

8. The device further includes connection means for establishing a connection with the other communication device via a first link in a first frequency band and a second link in a second frequency band. A communication device according to any one of claims 1 to 7, characterized by the features described herein.

9. The communication device performs the communication on the first link and the communication on the second link in a synchronized manner. The communication device according to feature 8.

10. The Probe Request frame, which includes the first Multi-Link element, is a frame for requesting Capability information regarding the multilink of the communication device. A communication device according to any one of claims 1 to 9, characterized by the features described herein.

11. The second Multi-Link element of the Probe Response frame transmitted by the first transmitting means includes Capability information relating to the multilink of the communication device. A communication device according to any one of claims 1 to 10, characterized by the features described herein.

12. The information contained in the second Multi-Link element included in the Probe Response frame transmitted by the first transmission means includes an HT Capabilities element. A communication device according to any one of claims 1 to 10, characterized by the features described herein.

13. The information contained in the second Multi-Link element included in the Probe Response frame transmitted by the first transmission means includes a VHT Capabilities element. A communication device according to any one of claims 1 to 10, characterized by the features described herein.

14. The information contained in the second Multi-Link element included in the Probe Response frame transmitted by the first transmitting means includes an EHT Capabilities element. A communication device according to any one of claims 1 to 10, characterized by the features described herein.

15. A method for controlling a communication device, A receiving process in which a Probe Request frame is received from another communication device, If a Probe Request frame containing a first Multi-Link element is received in the receiving step, a first transmission step is performed to transmit a Probe Response frame containing a second Multi-Link element containing information corresponding to the unique information for each link contained in the first Multi-Link element, If the receiving step receives a Probe Request frame that does not contain the first Multi-Link element, the second transmission step transmits a Probe Response frame that does not contain the information, A method for controlling a communication device, characterized by having the following features.

16. A program for causing a computer to function as one of the means of a communication device according to any one of claims 1 to 14.

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