Communication device, control method, and computer-readable storage medium

Abstract

A communication device for performing wireless communication conforming to the IEEE 802.11 standards series receives a predetermined signal related to a connection request from another communication device, and controls a response to the predetermined signal to connect the other communication device using a first channel in a case where the predetermined signal is received in a second channel different from the first channel.

Description

Technical Field

[0001] This invention relates to connection control technology in wireless LANs. Background Technology

[0002] As a communication standard related to wireless LANs (Wireless Local Area Networks), the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard is known. The IEEE 802.11 standard is a family of standards including IEEE 802.11a / b / g / n / ac / ax. Patent document 1 describes communication using OFDMA (Orthogonal Frequency Division Multiple Access) within the IEEE 802.11ax standard. High throughput can be achieved in wireless communication using OFDMA.

[0003] Currently, to further improve throughput, the IEEE 802.11be standard has been defined as a new standard in the IEEE 802.11 standard family. The IEEE 802.11be standard has explored multilink communication, in which an access point (AP) performs communication by establishing multiple radio links with a station (STA) in multiple frequency bands. In multilink communication, for example, the AP uses multiple frequency channels in the 2.4 GHz, 5 GHz, or 6 GHz bands to establish connections with the STA and simultaneously communicate with the STA using these frequency channels.

[0004] Citation List

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-050133 Summary of the Invention

[0007] Technical issues

[0008] Even in a multi-link communication environment, it's possible to assume the following scenario: due to hardware limitations of wireless communication devices, there exist APs and STAs that can transmit on one link but cannot receive on another. In this case, the AP can use multiple frequency channels to connect to STAs that can each use a single frequency channel. If each STA transmits signals by focusing only on the frequency channel it's connected to, then when the AP transmits using a given frequency channel, the signal might arrive on another frequency channel, thus preventing the AP from receiving the signal.

[0009] Solution to the problem

[0010] This invention provides a communication control technique that prevents simultaneous transmission operations on one frequency channel and reception operations on other frequency channels.

[0011] According to one aspect of the invention, a communication device is a communication device for performing wireless communication conforming to the IEEE 802.11 standard series, the communication device comprising: a receiving component for receiving a predetermined signal in relation to a connection request from another communication device; and a control component for controlling a response to the predetermined signal, in the case that the predetermined signal is received in a second channel different from a predetermined first channel, to use the first channel to connect to the other communication device.

[0012] Advantages of the invention

[0013] According to the present invention, it is possible to prevent the use of other frequency channels for receiving operations while using one of the multiple frequency channels for transmitting operations.

[0014] Other features and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings. Note that in all the drawings, the same reference numerals denote the same or similar components. Attached Figure Description

[0015] Embodiments of the invention are illustrated in conjunction with the accompanying drawings, which are included in and form part of this specification, and together with the specification serve to explain the principles of the invention.

[0016] Figure 1 This is a diagram illustrating an example configuration of a wireless communication system;

[0017] Figure 2 This is a block diagram illustrating an example of the hardware layout of an AP;

[0018] Figure 3 This is a block diagram illustrating an example of the functional layout of an AP;

[0019] Figure 4 This is a sequence diagram illustrating a first example of the connection processing procedure;

[0020] Figure 5 This is a sequence diagram illustrating a second example of the connection processing procedure;

[0021] Figure 6 This is a sequence diagram illustrating a third example of the connection processing procedure;

[0022] Figure 7 This is a sequence diagram illustrating a fourth example of the connection processing procedure;

[0023] Figure 8 This is a flowchart illustrating an example of the process of receiving and processing a probe request frame;

[0024] Figure 9 This is a flowchart illustrating an example of the process of receiving and processing an association request frame; and

[0025] Figure 10 This is a flowchart illustrating an example of the process for determining the channel of the main link. Detailed Implementation

[0026] In the following, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claimed invention. Several features are described in the embodiments, but it is not a limitation requiring all such features, and multiple such features can be suitably combined. Furthermore, in the drawings, the same reference numerals are given the same or similar arrangement, and redundant descriptions thereof are omitted.

[0027] (System configuration)

[0028] Figure 1 An example configuration of a wireless communication system according to an embodiment is shown. The wireless communication system includes an access point (AP 102) and a station (STA 103) as wireless communication devices in a wireless LAN, and performs wireless communication when STA 103 joins the network 101 formed by AP 102. As an example, it is assumed that STA 103 is configured to perform multi-link communication (in which multiple radio links are established with AP 102 for communication), and can send / receive frames in each of the multiple radio links. Figure 1 An example using both links 104 and 105 is shown. Channels in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands can be used in each link. Note that the frequency bands used are not limited to these; different bands such as the 60 GHz band can be used. Depending on the multi-link communication capability information between the STA and AP, channels in the 2.4 GHz and 5 GHz frequency bands can be combined, or multiple channels selected from the 6 GHz band can be combined. Multiple channels in a single frequency band can be used to perform multi-link communication. Note that... Figure 1 An example is shown, and multiple STAs can exist, as can other PAs. The positional relationship between APs and STAs can differ. Figure 1 The positional relationship between AP and STA is shown.

[0029] Assume that AP 102 is configured to perform multi-link communication, and to perform transmission operations on a first link while not performing reception operations on a second link different from the first link. In this embodiment, AP 102 determines the main link from multiple links and, for example, connects a specific type of STA to the main link. In this example, the specific type of STA may be, for example, a STA conforming to a standard older than the IEEE 802.11be standard, such as the IEEE 802.11ax standard, or an IEEE 802.11be STA that can only operate on a single link. Note that AP 102 can connect not only specific types of STAs to the main link, but also all STAs to the main link. This allows AP 102 to control the transmission timing in channels outside the main link based on the reception timing of signals from STAs accessing the channel on the main link. As a result, it prevents transmission opportunities in one link from occurring simultaneously with reception opportunities in other links. In this embodiment, an example of the arrangement of AP 102 for connecting STAs to the main link and the control processing performed by AP 102 will be described.

[0030] Note that this embodiment will describe the arrangement and processing of AP 102, but STA can perform at least some of the following processes, or the following processes can be performed in a wireless communication system other than a wireless LAN conforming to the IEEE 802.11 standard. That is, the processes performed by AP 102 as described below can be performed by any wireless communication device in any wireless communication system.

[0031] (Equipment layout)

[0032] Figure 2 This is a block diagram illustrating an example hardware configuration of AP 102 according to this embodiment. AP 102 includes, for example, a storage unit 201, a control unit 202, a functional unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207. Note that STA 103 may have the same arrangement as in AP 102.

[0033] Storage unit 201 includes one or more memories such as ROM and RAM, and stores computer programs configured to perform various types of operations, as described later, and various types of information such as communication parameters for wireless communication. Note that ROM is an abbreviation for Read Only Memory, and RAM is an abbreviation for Random Access Memory. Note that instead of memories such as ROM or RAM, or in addition to memories such as ROM or RAM, storage unit 201 may also include storage media such as floppy disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, or DVDs. Storage unit 201 may include multiple memories.

[0034] The control unit 202 is formed by one or more processors, such as a CPU and an MPU, and controls the entire AP 102, for example, by executing a computer program stored in the storage unit 201. Note that CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. In addition to controlling the entire AP 102, the control unit 202 may also be configured to perform processing for generating data or signals to be transmitted in communication with other communication devices (e.g., STA 103). Note that the control unit 202 may, for example, be configured to perform processing such as controlling the entire AP 102 in cooperation with the computer program stored in the storage unit 201 and the OS (operating system). The control unit 202 may include multiple processors, such as a multi-core processor, and the processing such as controlling the entire AP 102 may be performed by multiple processors. Furthermore, the control unit 202 may be formed by an ASIC (Application-Specific Integrated Circuit), a DSP (Digital Signal Processor), or a FPGA (Field-Programmable Gate Array).

[0035] Control unit 202 controls function unit 203 to perform predetermined processes such as image capture, printing, or projection. Function unit 203 is the hardware used by AP 102 to perform the predetermined processes. For example, if AP 102 is a camera, function unit 203 is an image capture unit and performs image capture processing. For example, if AP 102 is a printer, function unit 203 is a printing unit and performs printing processing. For example, if AP 102 is a projector, function unit 203 is a projection unit and performs projection processing. The data to be processed by function unit 203 may be data stored in storage unit 201, or data communicated with other communication devices (e.g., STA 103) via communication unit 206 (described later).

[0036] Input unit 204 receives various operations from the user. Output unit 205 provides various types of output to the user. In this example, the output of output unit 205 includes at least one of the following: display on a screen, audio output from a speaker, and vibration output. Note that input unit 204 and output unit 205 can both be implemented as a single module, similar to a touchpad. Input unit 204 and output unit 205 can each be incorporated into AP 102, or they can be configured as external devices connected to a communication device.

[0037] Communication unit 206 controls wireless communication conforming to the IEEE 802.11 standard family, or controls IP communication. In this embodiment, communication unit 206 is specifically configured to control wireless communication conforming to the IEEE 802.11be standard. Communication unit 206 controls antenna 207 to, for example, transmit / receive signals for wireless communication generated by control unit 202. AP 102 communicates data such as image data, document data, or video data with a communication counterpart device (e.g., STA 103) via communication unit 206. Note that antenna 207 can be prepared separately from communication unit 206, or it can be combined with communication unit 206 to form a module.

[0038] Antenna 207 is an antenna capable of communication in the Sub-GHz band, 2.4GHz band, 5GHz band, and 6GHz band respectively. Note that AP 102 may include a multi-band antenna as antenna 207, or may include multiple antennas corresponding to each frequency band. If AP 102 includes multiple antennas, AP 102 may include a single communication unit 206 for each antenna, or may include multiple communication units 206 corresponding to each antenna. Note that antenna 207 may be a single antenna or an antenna array. That is, antenna 207 may include multiple antenna elements and may be configured to perform, for example, MIMO (Multiple-Input Multiple-Output) communication.

[0039] Figure 3 An example of the functional layout of AP 102 is shown. AP 102 includes, for example, a probe request frame analysis unit 301 and a probe response frame generation unit 302 as functional components. Furthermore, AP 102 includes an association request frame analysis unit 303 and an association response frame generation unit 304. AP 102 also includes a main link management unit 305, a beacon frame generation unit 306, and a frame transmission / reception unit 307. For example, when the control unit 202 executes the program stored in the storage unit 201, it can achieve… Figure 3 The various functions are shown. Alternatively, dedicated hardware components can be prepared to implement each function. For example, Figure 3Some or all of the functions shown can be implemented as the functions of communication unit 206. In one example, when control unit 202 controls communication unit 206, it can achieve... Figure 3 The various functions shown.

[0040] The probe request frame analysis unit 301 analyzes probe request frames sent by nearby STAs to search for the AP and received by the AP 102. The probe request frame may include a multi-link element indicating whether the STA, as the sending source, supports multi-link communication. The probe request frame may also include a multi-bandelement containing information about the frequency bands and channels supported by the STA, and capability information indicating whether the STA supports channel switching. The AP 102 can specify the capabilities of the STA, as the sending source of the probe request frame, through the analysis by the probe request frame analysis unit 301.

[0041] The probe response frame generation unit 302 generates a probe response frame to be sent to the STA, which is the source of the probe request frame. The probe response frame may include, for example, a multi-link element indicating channel information of the primary link determined by AP102. The probe response frame may also include information instructing the STA to perform a channel switch. This information may be, for example, a channel switch announcement element or an extended channel switch announcement element.

[0042] The association request frame analysis unit 303 analyzes association request frames sent from the STA to the AP 102 to request connection to the AP 102 and received by the AP 102. The association request frame may include multi-link elements indicating whether the STA, as the sending source, supports multi-link communication. The association request frame may include multi-band elements as information on the frequency bands and channels supported by the STA, as well as capability information indicating whether the STA supports channel switching. The AP 102 can specify the capabilities of the STA, as the sending source of the association request frame, through the analysis of the association request frame analysis unit 303. Note that the AP 102 can obtain STA information by using either the probe request frame or the association request frame. That is, the STA can send only one of the probe request frame and the association request frame, including information about its own equipment.

[0043] The association response frame generation unit 304 generates an association response frame to be sent to the STA, which is the source of the association request frame. The association response frame includes a status code indicating the connection result.

[0044] The main link management unit 305 determines the frequency channel to be used in the main link. For example, the main link management unit 305 can set a fixed channel as the main link channel during AP 102 initialization. Furthermore, the main link management unit 305 can dynamically change the main link channel based on information about the operable frequency bands of the connected STA.

[0045] The beacon frame generation unit 306 generates a beacon frame to be sent to the surrounding area. STAs located near AP 102 can confirm the presence of AP 102 and obtain information about AP 102 by receiving the beacon frame. In this embodiment, the beacon frame includes a multi-link element indicating channel information of the primary link determined by AP 102.

[0046] The frame transmission / reception unit 307 performs the transmission / reception of various types of MAC (Media Access Control) frames and data frames. For example, the frame transmission / reception unit 307 transmits beacon frames generated by the beacon frame generation unit 306. When a probe request frame is received, the frame transmission / reception unit 307 transmits the frame to the probe request frame analysis unit 301. Similarly, when an association request frame is received, the frame transmission / reception unit 307 transmits the frame to the association request frame analysis unit 303. In addition, the frame transmission / reception unit 307 transmits frames generated by the probe response frame generation unit 302 or the association response frame generation unit 304 to the STA.

[0047] (The processing procedure within the system)

[0048] The following will describe some examples of the processing performed in the wireless communication system according to this embodiment. In the following description, it is assumed that AP 102 and STA 103 can communicate with each other using the 2.4 GHz and 5 GHz frequency bands, and AP 102 is configured to perform a transmit operation in one link while not performing a receive operation in the other. Note that the use of the 2.4 GHz and 5 GHz frequency bands is merely an example, and the following discussion applies to other combinations of frequency bands. The following discussion similarly applies to the case of using two or more different channels in the same frequency band. For example, AP 102 can be configured as two access points to communicate by establishing radio links in two separate frequency bands. For example, AP 102 can be configured to communicate in each frequency band using two physically separate communication circuits, or it can be configured to communicate in each frequency band using a single physical communication circuit that is logically divided into two circuits. In this case, AP 102 will determine the link formed by the channel in the 2.4 GHz frequency band as the main link and perform the processing of connecting the STA 103, which is attempting to connect, using the main link.

[0049] For example, when AP 102 and STA 103 are each powered on, the following process begins. In at least one of AP 102 and STA 103, this process may begin when a user or application instructs that multi-link communication be initiated. Alternatively, in at least one of AP 102 and STA 103, this process may begin when the amount of data to be communicated with the other device becomes equal to or greater than a predetermined threshold. Note, for example, that this process may be implemented when the control unit 202 of AP 102 (and STA 103) executes a program stored in storage unit 201.

[0050] <Processing Example 1>

[0051] Figure 4 This illustration shows a first example of the process performed when establishing a connection between AP 102 and STA 103. In this process, if AP 102 receives a probe request frame from a predetermined STA in a non-primary link, AP 102 sends a probe response frame to instruct STA 103 to switch its operating channel. The predetermined STA is, for example, an STA operating in a single link conforming to a standard older than IEEE 802.11be, such as IEEE 802.11ax, or an STA conforming to IEEE 802.11be and operating only in a single link. In the following description, STA 103 is an STA operating in a single link and in the 5 GHz band.

[0052] First, STA 103 sends a probe request frame (S401) including multi-band elements indicating the supported frequency bands and channels, and requests information from AP 102 (e.g., capability information). Note that in the probe request frame sent by STA 103, the 2.4 GHz band is set as the supported frequency band information.

[0053] Upon receiving a probe request frame, AP 102 analyzes the frame. Then, AP 102 identifies from the information in the multi-band elements whether STA 103 can operate in the main link channel (2.4 GHz band). In this example, AP 102 identifies that STA 103 can operate in the main link channel. Therefore, AP 102 generates a probe response frame including information elements for switching the operating channel of STA 103 to the main link channel and sends this frame to STA 103 (S402). This information element is, for example, a channel switching notification element.

[0054] Upon receiving a probe response frame, STA103 switches its operating band from the 5GHz band to the 2.4GHz band and begins operation in the main link channel (S403). Then, a radio link establishment process is performed between AP 102 and STA103 in the 2.4GHz band (S404). During the link establishment process, an authentication request frame and an authentication response frame are exchanged between AP 102 and STA103 for authentication. Furthermore, an association request frame and an association response frame are exchanged between AP 102 and STA 103 for connection processing. In this example, if AP 102 sends an association response frame to STA103 indicating a successful connection, with the SUCCESS status code set to indicate the connection result, the connection processing is complete. After completing the link establishment process, STA103 can, for example, send a data frame (S405). As described above, in Figure 4 In the example shown, before performing the link establishment process (S404), AP 102 causes STA 103 to switch its operating channel to the primary link channel. This enables AP 102 to establish a connection to STA 103 in the primary link channel.

[0055] <Processing Example 2>

[0056] Then, refer to Figure 5A second example describes the process performed when establishing a connection between AP 102 and STA 103. In this example, if AP 102 receives a probe request frame from STA 103 on a non-primary link, AP 102 does not respond with a probe response frame. If STA 103 does not receive a probe response frame, STA 103 changes its operating frequency and retransmits the probe request frame using a channel in a different frequency band. This allows AP 102 to shift STA 103's operating frequency to the primary link's frequency band, thereby using a channel on the primary link to establish a connection.

[0057] In this process, STA103 transmits a probe request frame in the 5GHz band, which is the operating frequency band. This probe request frame includes a multi-band element (S501) indicating the supported frequency bands and channels. S501 and... Figure 4 The process is the same as S401. AP 102 analyzes the probe request frame and identifies from the information of the multi-band elements that STA 103 can operate in the main link channel. Then, AP 102 does not respond with a probe response frame to shift the operating frequency of STA 103 to the 2.4 GHz band.

[0058] If STA 103 cannot receive a probe response frame in the 5GHz band, for example, within a predetermined time period since the probe request frame was sent, STA 103 switches its operating channel to the 2.4GHz band (S502). Then, STA 103 sends a probe request frame in the 2.4GHz band, including multi-band elements indicating the supported band and channel (S503). At this time, the information indicating the 5GHz band is set to the supported band information. Therefore, AP 102 receives the probe request frame in the 5GHz band, which serves as the main link.

[0059] If AP 102 receives a probe request frame on the main link, AP 102 sends a probe response frame to allow STA 103 to connect (S504). Afterwards, link establishment processing is performed (S505), and data is sent / received (S506). These processes are related to... Figure 4 The processing in S404 and S405 is the same. As mentioned above, the same applies in... Figure 5 In the example shown, before performing the link establishment process (S505), AP 102 causes STA 103 to switch its operating channel to the main link channel. This enables AP 102 to establish a connection to STA 103 in the main link channel.

[0060] <Processing Example 3>

[0061] In the examples of Processing Example 1 and Processing Example 2 above, it has been illustrated that the operating frequency of STA103 changes before the link establishment process; however, the operating frequency can change after the link establishment process. In this processing example, reference will be made to... Figure 6 Describe this process. In this process, STA103 sends an association request frame on a non-primary link. Upon receiving the association request frame, AP 102 establishes a connection and then sends a probe response frame to STA103 to instruct it to switch the operating channel of STA103. This allows AP 102 to transfer the operating frequency of STA103 to the primary link band after the connection is established, thereby performing communication on the primary link channel. Note that in this example, AP 102 and STA103 send / receive probe request and probe response frames before the link establishment process.

[0062] In this process, AP 102 and STA 103 perform authentication procedures on a non-main link. Specifically, STA 103 sends an authentication request frame to AP 102 in the 5GHz band (S601). Then, AP 102 sends an authentication response frame to STA 103 in the 5GHz band as a response (S602). Next, STA 103 sends an association request frame in the 5GHz band, requesting AP 102 to establish a connection (S603), where the association request frame includes multi-band elements indicating the frequency bands and channels supported by STA 103 itself. In this example, the information indicating the 2.4GHz band is set to the supported frequency band information.

[0063] Upon receiving an association request frame, AP 102 analyzes the frame. From the information in the multi-band elements of the frame, AP 102 identifies that STA 103 can operate in the main link channel (2.4GHz band). In response, AP 102 sends an association response frame to STA 103, with the SUCCESS status code set to indicate the connection result (S604). Subsequently, AP 102 sends a probe response frame including a channel switching notification element to switch the operating channel of STA 103 to the main link channel (S605). Upon receiving the probe response frame, STA 103 switches its operating band from the 5GHz band to the 2.4GHz band and begins operation in the main link channel (S606). Afterwards, data is transmitted / received between AP 102 and STA 103 (S607).

[0064] As mentioned above, in Figure 6In the example shown, after performing the link establishment process, AP 102 causes STA 103 to switch its operating channel to the primary link channel. This allows AP 102 to establish a connection to STA 103 within the primary link channel.

[0065] <Processing Example 4>

[0066] In Example 3, the process of sending a probe response frame to change the operating frequency of STA 103 after establishing a link on a non-primary link has been described. In this example, STA 103 attempts to establish a link on the primary link, not on the non-primary link. That is, AP 102 rejects the connection when it receives an association request frame from STA 103 on the non-primary link, prompting STA 103 to switch its operating frequency. (Refer to...) Figure 7 An example describing the processing procedure. Note that, also in this processing example, probe request frames and probe response frames are sent / received between AP 102 and STA 103 before the link establishment process.

[0067] Similarly, in this processing example, AP 102 and STA 103 first perform authentication processes on a non-master link (S701 and S702). Then, STA 103 sends an association request frame in the 5GHz band, requesting AP 102 to connect (S703), where the association request frame includes multi-band elements indicating the frequency bands and channels supported by STA 103 itself. These processes are related to... Figure 6 The processing in S601 to S603 is the same. Upon receiving an association request frame, AP 102 analyzes the frame. AP 102 identifies from the information of the multi-band elements that STA 103 can operate in the channel of the main link. In response, AP 102 sends an association response frame to STA 103 with the FAIL indicating connection failure set to a status code indicating connection result (S704). This allows STA 103 to recognize the connection failure in the 5GHz band. In response to the connection failure, STA 103 switches its operating frequency to the 2.4GHz band (S705). Subsequently, AP 102 and STA 103 perform link establishment processing in the 2.4GHz band (S706), and send / receive data after the link is established (S707).

[0068] As mentioned above, in Figure 7 In the example shown, during the link establishment process, AP 102 causes STA 103 to switch its operating channel to the primary link channel. This allows AP 102 to establish a connection to STA 103 within the primary link channel.

[0069] (Processing performed by AP 102)

[0070] Subsequently, an example of the process performed by AP 102 in the above system operation will be described.

[0071] Reference Figure 8 This describes the process when AP 102 causes STA 103 to change its operating frequency in response to a probe request frame. First, AP 102 determines whether the channel from which the probe request frame has been received is a primary link channel (step S801). If AP 102 receives the probe request frame in a primary link channel (yes in step S801), AP 102 generates a probe response frame that does not include channel switch information (step S804). Then, AP 102 sends the generated frame to STA 103 (step S809) and ends the process. Note that the probe response frame is an example of a frame that includes information for changing the channel, and other frames may be sent in step S809. On the other hand, if AP 102 receives the probe request frame in a non-primary link channel (no in step S801), AP 102 determines whether the frame includes a multi-link element (step S802). If AP 102 determines that the frame includes a multi-link element ("Yes" in step S802), then AP 102 recognizes that the STA supports multi-link communication. In this case, STA 103 can operate in the primary link channel while operating in a non-primary link channel. Therefore, AP 102 sets the primary link channel in the multi-link element (step S803). Then, AP 102 generates a probe response frame that does not include channel switching information and sends the frame to STA 103 (steps S804 and S809).

[0072] On the other hand, if AP 102 determines that the frame does not include multi-link elements ("No" in step S802), AP 102 identifies that the STA, which cannot perform multi-link communication, has already sent a probe request frame in a non-primary link channel. In this case, AP 102 determines whether the probe request frame includes multi-band elements (step S805). If AP 102 determines that the probe request frame does not include multi-band elements ("No" in step S805), then STA 103 cannot operate in the primary link channel, and therefore the process ends directly. In this case, AP 102 does not send a probe response frame, so STA 103 cannot establish a link with AP 102. On the other hand, if the probe request frame includes multi-band elements ("Yes" in step S805), then AP 102 determines whether STA 103 can operate in the primary link channel based on this information (step S806). If AP 102 determines that STA 103 cannot operate in the main link channel (No in step S806), the process ends directly. In this case, AP 102 does not send a probe response frame, therefore STA 103 cannot establish a link with AP 102. If AP 102 determines that STA 103 can operate in the main link channel (Yes in step S806), AP 102 determines whether STA 103 supports channel switching (step S807). If AP 102 determines that STA 103 does not support channel switching (No in step S807), AP 102 cannot send an indication to STA 103 to change the channel, therefore the process ends directly. In this case, AP 102 does not send a probe response frame, therefore STA 103 cannot establish a link with AP 102. However, in this case, STA 103 may be able to change its operating frequency and send a probe request frame in the main link channel, thereby establishing a link with AP 102.

[0073] In step S807, if AP 102 uses, for example, a channel switching announcement element for channel switching, AP 102 determines whether STA 103 supports this element. In this case, AP 102 can perform the determination by checking the Spectrum Management bit in the Capabilities field of the probe request frame from STA 103. If AP 102 uses an Extended Channel Switching announcement element, AP 102 can determine whether STA 103 supports this element. In this case, AP 102 can perform the determination by checking the Extended Channel Switching bit in the Extended Capabilities field of the probe request frame. AP 102 can determine whether STA 103 supports channel switching using other capability information in different ways.

[0074] If AP 102 determines that STA 103 supports channel switching ("Yes" in step S807), then AP 102 generates a probe response frame indicating that the primary link channel has been set to channel switching information (step S808). Then, AP 102 sends the generated frame to STA 103 to change the operating frequency of STA 103 to the primary link's frequency band. Using this operation, AP 102 can enable STA 103, which can operate in the primary link's channel, to operate in the primary link's channel.

[0075] Then, refer to Figure 9 This describes an example of the process where AP 102 causes STA 103 to change its operating frequency during / after link establishment processing. This processing occurs when AP 102 receives an association request frame. First, AP 102 performs a process to determine the channel of the primary link (step S901). In this example, AP 102 decides to use a channel in the 2.4 GHz band as the primary link channel. Note that if the primary link channel is fixed, the process in step S901 can be skipped. Figure 8 Before the processing in step S801, processing for determining the channel of the main link can also be performed.

[0076] AP 102 determines whether the channel through which the association request frame has been received is the main link channel (step S902). If the channel through which the association request frame has been received is the main link channel, AP 102 determines whether the frame includes a multi-link element (step S903). If the frame includes a multi-link element, AP 102 determines that STA 103 supports multi-link communication; if the frame does not include a multi-link element, it determines that STA 103 does not support multi-link communication. If AP 102 determines that the frame includes a multi-link element ("yes" in step S903), AP 102 determines whether STA 103 can operate in the main link channel (step S904). For example, AP 102 can determine whether STA 103 can operate in the main link channel based on STA 103's capability information obtained using frames such as association request frames.

[0077] If AP 102 determines that STA 103 cannot operate in the main link channel (No in step S904), then AP 102 cannot change the operating frequency of STA 103 to the main link frequency band, thus preventing a connection. That is, AP 102 sends an association response frame with the FAIL status code set to STA 103, thereby refusing the connection (step S905). On the other hand, if AP 102 determines that STA 103 can operate in the main link channel (Yes in step S904), then AP 102 determines whether the predetermined connection conditions are met (step S906). Note that if the channel that has received the association request frame is the main link channel (Yes in step S902), the determination process in step S906 can also be performed. Connection conditions include, for example, the condition that the number of connected STAs is less than the maximum number of STAs that AP 102 can accommodate. That is, for example, if STA103 is connected to AP102, the connection conditions include conditions under which communication services can be provided, taking into account the fact that AP102 may not be able to provide communication services to STA103 depending on its capabilities. If AP102 determines that the connection conditions are not met ("No" in step S906), AP102 sends an associated response frame with FAIL set to the status code to STA103, thereby refusing the connection (step S905). On the other hand, if AP102 determines that the connection conditions are met ("Yes" in step S906), AP102 sends an associated response frame with SUCCESS set to the status code to STA103, thereby allowing the connection (step S907).

[0078] If AP 102 determines that the association request frame does not include a multi-link element ("No" in step S903), then AP 102 determines whether the frame includes a multi-band element (step S908). If AP 102 determines that the frame includes a multi-band element ("Yes" in step S908), then AP 102 determines whether STA 103 can operate in the main link channel (step S909). Then, if AP 102 determines that STA 103 can operate in the main link channel ("Yes" in step S909), then AP 102 determines whether STA 103 supports channel switching (step S910). This determination can be based on the value set in the multi-band element. If AP 102 determines that STA 103 supports channel switching ("Yes" in step S910), then AP 102 determines whether the connection conditions are met (step S911). Note that if AP 102 determines in steps S908 to S910 that STA 103 cannot operate in the main link channel or that it is impossible to change the operating frequency of STA 103 to the frequency of the main link, then AP 102 will transfer the processing to step S905 to refuse the connection. If AP 102 determines that the connection conditions are not met ("No" in step S911), then AP 102 will also refuse the connection (step S905).

[0079] If STA103 can operate in the main link channel, the operating frequency can be changed to the main link channel, and the connection condition is met ("Yes" in step S911). AP 102 enables the connection of STA 103. AP 102 sends an associated response frame with SUCCESS set to the status code to STA103, thereby allowing the connection (step S912). Afterwards, AP 102 sends a probe response frame to STA103 indicating that the main link channel has been set to a channel switching information (step S913). This switches the connection between AP 102 and STA103 to a connection via the main link.

[0080] Note that in the above process, instead of sending the associated response frame with the FAIL status code set in step S905, the associated response frame may not be sent. In this case, STA103 can identify connection failure based on the fact that the associated response frame has not been received. Note that in response, STA103 can change its operating frequency to the main link's frequency band and resend the associated request frame to establish a connection.

[0081] The case where the main link channel is fixed has been described above. However, for example, the main link channel can be dynamically determined in step S901. (Refer to...) Figure 10The process for determining the primary link channel in this situation is described. In this process, AP 102 first determines whether the association request frame includes multi-band elements (step S1001). Then, for the STAs currently connected to AP 102 and STA 103, which is the source of the frame, AP 102 calculates the number of STAs operable in each frequency band (step S1002 or S1003). For example, if AP 102 determines that the frame includes multi-band elements ("Yes" in step S1001), AP 102 calculates the number of STAs based on the capability information of the STAs currently connected to its own device and the multi-band elements (step S1002). On the other hand, if AP 102 determines that the association request frame does not include multi-band elements ("No" in step S1001), AP 102 calculates the number of STAs based on the frequency bands on which the frame has been received (step S1003). For example, among the connected STAs, there are three STAs that can operate in the 2.4 GHz band and three STAs that can operate in the 5 GHz band. In step S1002, if STA 103 supports both the 2.4 GHz and 5 GHz bands, the number of STAs that can operate in the 2.4 GHz band is calculated to be 4, and the number of STAs that can operate in the 5 GHz band is also calculated to be 4. In step S1003, if STA 103 sends an association request frame in the 5 GHz band, the number of STAs that can operate in the 2.4 GHz band is calculated to be 3, and the number of STAs that can operate in the 5 GHz band is also calculated to be 4. Then, AP 102 sets the channel in the band with the largest number of operable STAs as the channel of the main link (step S1004).

[0082] At this point, AP 102 determines whether the channel of the primary link set in step S1004 has changed from the previously set channel of the primary link (step S1005). If the channel of the primary link has not changed ("No" in step S1005), AP 102 directly ends the process. On the other hand, if the channel of the primary link has changed ("Yes" in step S1005), AP 102 performs a process to change the operating frequency for a predetermined STA among the connected STAs. The predetermined STA may be, for example, a STA operating in a single link conforming to a standard older than the IEEE 802.11be standard, such as the IEEE 802.11ax standard, or an IEEE 802.11be STA that can only operate in a single link. AP 102 sends a probe response frame to the predetermined STA, in which the changed channel of the primary link is set as channel switching information (step S1006). For STAs operating in multiple links, AP 102 updates the channel information of the primary link included in the multi-link element of the beacon frame to the changed channel information. This allows AP 102 to configure the appropriate channel for the main link as needed.

[0083] Note that if the primary link channel is configured, it may not be necessary to change the operating frequency of STA 103. That is, even if the receive channel is not the primary link channel when an association request frame is received, the receive channel can be configured to be the primary link channel by changing the primary link channel. Therefore, for example, the determination result in step S902 can be based on... Figure 9 The settings of the main link channel in step S901 are changed.

[0084] Note that the methods described above for wireless LANs conforming to the IEEE 802.11 standard family have been described. However, the same discussion applies to communication devices that can establish multiple radio links. That is, the above methods can be applied as control for connecting a communication counterpart with predetermined characteristics to one of multiple radio links. Note that the AP 102 described above is not always a communication device that cannot simultaneously perform transmission in one of two or more frequency bands and reception in other frequency bands. That is, the AP 102 can determine a frequency band based on given criteria and perform the above processing to enable the STA 103 to operate in that frequency band.

[0085] The present invention can be implemented by supplying a program for implementing one or more functions of the above embodiments to a system or device via a network or storage medium, and causing one or more processors of the system or device's computer to read and execute the program. The present invention can also be implemented by circuitry (e.g., an ASIC) for implementing one or more functions.

[0086] This invention is not limited to the embodiments described above, and various changes and modifications can be made within the spirit and scope of this invention. Therefore, the appended claims are made to inform the public of the scope of this invention.

[0087] This application claims priority to Japanese Patent Application 2020-150739, filed on September 8, 2020, which is incorporated herein by reference.

Claims

1. A communication device for performing wireless communication conforming to the IEEE 802.11 standard family, the communication device comprising: A communication component for multi-link communication with other communication devices using multiple links established with other communication devices, wherein each of the multiple links operates on a different channel; A receiving component, configured to receive probe request frames from the other communication devices; as well as A control unit, configured to, upon receiving the probe request frame in a second channel different from the first channel, in order to enable other communication devices to communicate with the communication device using the first channel, execute control to send a probe response frame as a response using the second channel different from the first channel, including information indicating that a switchback to the first channel should be performed. The information indicating that a switch to the first channel should be performed is one of the channel switching notification element and the extended channel switching notification element.

2. The communication device according to claim 1, wherein, If the other communication device is able to operate in the first channel, the control unit performs control to send the probe response frame to the other communication device, including information indicating that a switch to the first channel should be performed; if the other communication device is not able to operate in the first channel, the control unit does not perform the control.

3. The communication device according to claim 2, wherein, The control unit determines whether the other communication device can operate in the first channel based on the information included in the probe request frame.

4. The communication device according to claim 1, wherein, If the other communication device supports channel switching, the control unit performs control to send the probe response frame to the other communication device, which includes information indicating that a switch to the first channel should be performed; if the other communication device does not support channel switching, the control unit does not perform the control.

5. The communication device according to claim 4, wherein, The control unit determines whether the other communication devices support channel switching based on the information included in the probe request frame.

6. The communication device according to claim 1, further comprising a determining component, the determining component being configured to determine the first channel from a plurality of channels available for use by the communication device.

7. The communication device according to claim 6, wherein, The determining component determines the first channel based on the number of other devices connected to the communication device that can operate in each of the plurality of channels, and the channels that the other communication devices can operate.

8. The communication device according to claim 7, wherein, The determining component determines the first channel based on the number of other devices connected to the communication device that can operate in each of the plurality of channels, and the channels that have received the probe request frame.

9. The communication device according to claim 7, wherein, If the first channel is changed, the control unit also performs control to send information to other connected devices indicating that a switch to the changed first channel should be performed.

10. The communication device according to claim 7, wherein, If the first channel is changed, the control unit also performs control to transmit beacon frames through the changed first channel.

11. The communication device according to claim 1, wherein, The communication device is capable of communicating using both the first channel and the second channel, but cannot use the other channel for receiving when transmitting using either the first channel or the second channel.

12. The communication device according to claim 1, wherein, The first channel is a channel in the first frequency band, and the second channel is a channel in the second frequency band.

13. A computer-readable storage medium storing a program for causing a computer to function as a communication device as defined in any one of claims 1 to 12.

14. A control method performed by a communication device for performing wireless communication conforming to the IEEE 802.11 series of standards, the control method comprising: Multiple links are established with other communication devices to perform multi-link communication with the other communication devices, wherein each of the multiple links operates on a different channel; Receive probe request frames from the other communication devices; as well as If the probe request frame is received in a second channel different from the first channel, in order for the other communication devices to use the first channel to communicate with the communication device, control is executed to send a probe response frame, including information indicating that a switchback to the first channel should be made, using the second channel different from the first channel. The information indicating that a switch to the first channel should be performed is one of the channel switching notification element and the extended channel switching notification element.

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