Communication device, control method, and program

Abstract

To provide a communication control technology that prevents reception on the other side in parallel with transmission on one side of a plurality of frequency channels.SOLUTION: A communication device that performs wireless communication conforming to the IEEE802.11 standard series receives a predetermined signal regarding a connection request from another communication device, and controls a response to a predetermined signal in order to connect the other communication device on the first channel when the predetermined signal is received at a second channel different from a predetermined first channel.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a connection control technique for a wireless LAN. [Background technology]

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is known as a communication standard for wireless local area networks (WLANs). The IEEE 802.11 standard is a series of standards including the IEEE 802.11a / b / g / n / ac / ax standards. Patent Document 1 describes that the IEEE 802.11ax standard performs communication using orthogonal frequency division multiple access (OFDMA). Wireless communication using OFDMA can achieve high peak throughput.

[0003] Currently, the IEEE802.11be standard is being developed as a new standard in the IEEE802.11 series to further improve throughput. The IEEE802.11be standard considers multi-link communication, in which one access point (AP) communicates with one station (STA) by establishing multiple wireless links over multiple frequency bands. In multi-link communication, for example, an AP establishes a connection with a STA using multiple frequency channels in the 2.4 GHz, 5 GHz, or 6 GHz frequency bands, and communicates in parallel over each frequency channel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-050133 Summary of the Invention [Problem to be solved by the invention]

[0005] Even in a multi-link communication environment, due to hardware limitations of wireless communication devices, there may be cases where APs or STAs cannot receive on one link while transmitting on another. In such cases, an AP may connect to STAs that can each use a single frequency channel over multiple frequency channels. In this case, if these STAs transmit signals only on the frequency channel they are connected to, when the AP transmits a signal on one frequency channel, the signal may arrive on another frequency channel and be unable to be received.

[0006] The present invention provides a communication control technique that prevents transmission on one of a plurality of frequency channels from occurring in parallel with reception on another. [Means for solving the problem]

[0007] A communication device according to one embodiment of the present invention is a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, and has a receiving means for receiving a predetermined signal regarding a connection request from another communication device, and a control means for controlling a response to the predetermined signal when the predetermined signal is received on a second channel different from a predetermined first channel, in order to connect the other communication device on the first channel. [Effects of the Invention]

[0008] According to the present invention, it is possible to prevent transmission on one of a plurality of frequency channels from occurring in parallel with reception on another. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Figure 2] FIG. 2 illustrates an example of the hardware configuration of an AP. [Figure 3] FIG. 2 is a diagram illustrating an example of a functional configuration of an AP. [Figure 4] FIG. 10 is a diagram illustrating a first example of the flow of a connection process. [Figure 5]FIG. 10 is a diagram illustrating a second example of the flow of connection processing. [Figure 6] FIG. 10 is a diagram illustrating a third example of the flow of connection processing. [Figure 7] FIG. 10 is a diagram illustrating a fourth example of the flow of connection processing. [Figure 8] FIG. 10 is a diagram illustrating an example of the flow of a Probe Request frame reception process. [Figure 9] FIG. 10 is a diagram illustrating an example of the flow of an Association Request frame reception process. [Figure 10] FIG. 10 is a diagram illustrating an example of the flow of a channel determination process for a primary link. DETAILED DESCRIPTION OF THE INVENTION

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

[0011] (System Configuration) FIG. 1 shows an example of the configuration of a wireless communication system according to this embodiment. This wireless communication system includes a wireless LAN access point (AP 102) and a station (STA 103) as wireless communication devices. The STA 103 participates in a network 101 formed by the AP 102, thereby enabling wireless communication. Here, the STA 103 is configured to be capable of multi-link communication, which establishes multiple wireless links with the AP 102 for communication, and is capable of transmitting and receiving frames via each of the multiple wireless links. FIG. 1 shows an example in which two links, a first link 104 and a second link 105, are used. Channels in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands may be used for each link. However, the frequency bands used are not limited to these, and other frequency bands, such as the 60 GHz band, may also be used. Depending on the multi-link communication capability information of the STA and the AP, a combination of channels in the 2.4 GHz band and the 5 GHz band may be used, or a combination of multiple channels selected from the 6 GHz band may also be used. Furthermore, multi-link communication may be performed using multiple channels within a single frequency band. Note that Figure 1 is an example, and multiple STAs may exist, and other APs may also exist. Furthermore, the positional relationship between the AP and the STAs may differ from that shown in Figure 1.

[0012] The AP 102 is capable of multi-link communication, but is configured so that while transmitting on a first link, it cannot receive on a second link different from the first link. In this embodiment, the AP 102 determines a primary link from among multiple links and connects, for example, a specific type of STA to the primary link. Here, the specific type of STA may be, for example, an STA that complies with an older version of IEEE 802.11be, such as IEEE 802.11ax, or an IEEE 802.11be STA that can only operate on a single link. Note that the AP 102 may connect all STAs to the primary link, rather than only to a specific type of STA. This allows the AP 102 to control the transmission timing of channels of non-primary links according to the reception timing of signals from STAs accessing channels on the primary link. As a result, it is possible to prevent transmission opportunities on one link and reception opportunities on other links from occurring simultaneously. In this embodiment, a configuration of the AP 102 that connects STAs to the primary link and an example of the control process executed by the AP 102 are described.

[0013] In this embodiment, the configuration and processing of the AP 102 will be described, but at least a part of the following processing may be executed by a STA, or the following processing may be executed in a wireless communication system other than a wireless LAN conforming to the IEEE 802.11 standard. In other words, the processing executed by the AP 102 described below may be executed by any wireless communication device in any wireless communication system.

[0014] (Device configuration) 2 is a diagram illustrating an example of the hardware configuration of the AP 102 according to this embodiment. The AP 102 includes, for example, 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. The STA 103 may also have a similar configuration.

[0015] The storage unit 201 is configured to include one or more memories such as ROM and RAM, and stores various information such as computer programs for performing various operations described below and communication parameters for wireless communication. ROM is an acronym for Read Only Memory, and RAM is an acronym for Random Access Memory. The storage unit 201 may include storage media such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, a DVD, etc., in addition to or instead of memories such as ROM and RAM. The storage unit 201 may also include multiple memories.

[0016] The control unit 202 is configured with one or more processors, such as a CPU or an MPU, and controls the entire AP 102 by executing a computer program stored in the storage unit 201, for example. Note that CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit 202 may be configured to perform processes for generating data and signals to be transmitted in communication with other communication devices (e.g., the STA 103) in addition to the overall control of the AP 102. Note that the control unit 202 may be configured to perform processes such as the overall control of the AP 102 in cooperation with a computer program stored in the storage unit 201 and an OS (Operating System). The control unit 202 may also include multiple processors, such as a multi-core processor, and may perform processes such as the overall control of the AP 102 using the multiple processors. The control unit 202 may also be configured with an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or the like.

[0017] Furthermore, the control unit 202 controls the functional unit 203 to execute predetermined processes such as capturing images, printing, and projection. The functional unit 203 is hardware that causes the AP 102 to execute predetermined processes. For example, if the AP 102 is a camera, the functional unit 203 is an imaging unit that performs imaging processing. For example, if the AP 102 is a printer, the functional unit 203 is a printing unit that performs printing processing. For example, if the AP 102 is a projector, the functional unit 203 is a projection unit that performs projection processing. The data processed by the functional unit 203 may be data stored in the storage unit 201, or may be data communicated with another communication device (e.g., STA 103) via the communication unit 206, which will be described later.

[0018] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes, for example, at least one of a display on a screen, an audio output from a speaker, and a vibration output. Note that both the input unit 204 and the output unit 205 may be implemented by a single module, such as a touch panel. Furthermore, the input unit 204 and the output unit 205 may each be built into the AP 102, or may be configured as an external device connected to a communication device.

[0019] The communication unit 206 controls wireless communication compliant with the IEEE 802.11 standard series and IP communication. In this embodiment, the communication unit 206 is configured to control wireless communication compliant with the IEEE 802.11be standard in particular. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communication generated by, for example, the control unit 202. The AP 102 communicates data such as image data, document data, and video data with a communication partner device (for example, the STA 103) via the communication unit 206. The antenna 207 may be provided separately from the communication unit 206, or may be configured as a single module together with the communication unit 206.

[0020] Antenna 207 is an antenna capable of communication in the sub-GHz band, 2.4 GHz band, 5 GHz band, and 6 GHz band. Note that AP 102 may have a multi-band antenna as antenna 207, or may have multiple antennas corresponding to each frequency band. If AP 102 has multiple antennas, it may have one communication unit 206 for the multiple antennas, or multiple communication units 206 corresponding to each of the multiple antennas. Note that antenna 207 may be a single antenna or an antenna array. That is, antenna 207 may have multiple antenna elements and be configured to be able to perform communication using, for example, MIMO (Multi-Input and Multi-Output).

[0021] FIG. 3 shows an example of the functional configuration of the AP 102. The AP 102 includes, for example, a Probe Request frame analysis unit 301 and a Probe Response frame generation unit 302 as its functional configuration. The AP 102 also includes an Association Request frame analysis unit 303 and an Association Response frame generation unit 304. The AP 102 also includes a Primary Link Management unit 305, a Beacon frame generation unit 306, and a frame transmission / reception unit 307. Each function in FIG. 3 can be realized, for example, by the control unit 202 executing a program stored in the storage unit 201. Dedicated hardware for realizing each function may also be provided. For example, some or all of the functions shown in FIG. 3 may be realized as functions of the communication unit 206. In one example, each function in FIG. 3 may be realized by the control unit 202 controlling the communication unit 206.

[0022] The Probe Request frame analysis unit 301 analyzes Probe Request frames that are sent by surrounding STAs to search for APs and are received by the AP 102. Here, the Probe Request frame may include a Multi Link element that indicates whether the sending STA supports multi-link communication. The Probe Request frame may also include a Multi Band element that provides information on the frequency bands and channels supported by the sending STA, and capability information on whether the sending STA supports Channel Switch. The AP 102 can identify the capabilities of the STA that sent the Probe Request frame through analysis by the Probe Request frame analysis unit 301.

[0023] The Probe Response frame generator 302 generates a Probe Response frame for transmission to the STA that sent the Probe Request frame. The Probe Response frame may include, for example, a Multi Link element that indicates channel information of the primary link determined by the AP 102. The Probe Response frame may also include information that instructs 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.

[0024] The Association Request frame analyzer 303 analyzes an Association Request frame that a STA sends to the AP 102 to request connection with the AP 102 and that is received by the AP 102. The Association Request frame may include a Multi Link element indicating whether the STA that sent the frame supports multi-link communication. The Association Request frame may also include a Multi Band element, which is information about the frequency bands and channels supported by the STA that sent the frame, and capability information indicating whether the STA supports Channel Switching. The AP 102 can identify the capabilities of the STA that sent the Association Request frame through analysis by the Association Request frame analyzer 303. The AP 102 can obtain STA information using either a Probe Request frame or an Association Request frame. That is, a STA may transmit information about its own device in only either a Probe Request frame or an Association Request frame.

[0025] The Association Response frame generator 304 generates an Association Response frame for transmission to the STA that sent the Association Request frame. The Association Response frame includes a status code indicating the connection result, etc.

[0026] The primary link management unit 305 determines the frequency channel to be used in the primary link. The primary link management unit 305 may set a fixed channel as the channel of the primary link, for example, when initializing the AP 102. The primary link management unit 305 may also dynamically change the channel of the primary link according to information about the frequency bands in which the currently connected STAs can operate.

[0027] The Beacon frame generator 306 generates a Beacon frame to be transmitted to the surrounding area. STAs around the AP 102 can recognize the presence of the AP 102 by receiving this Beacon frame and can also obtain information about the AP 102. In this embodiment, the Beacon frame includes a Multi Link element indicating channel information of the primary link determined by the AP 102, etc.

[0028] The frame transmitting / receiving unit 307 transmits and receives various MAC (Media Access Control) frames and data frames. For example, the frame transmitting / receiving unit 307 sends out a Beacon frame generated by the Beacon frame generating unit 306. Furthermore, when the frame transmitting / receiving unit 307 receives a Probe Request frame, it transfers the frame to the Probe Request frame analyzing unit 301. Similarly, when the frame transmitting / receiving unit 307 receives an Association Request frame, it transfers the frame to the Association Request frame analyzing unit 303. Furthermore, the frame transmitting / receiving unit 307 transmits frames generated by the Probe Response frame generating unit 302 and the Association Response frame generating unit 304 to the STA.

[0029] (Processing flow within the system) Next, several examples of processing executed in the wireless communication system of this embodiment will be described. In the following, it is assumed that the AP 102 and the STA 103 are capable of communicating using the 2.4 GHz band and the 5 GHz band, and that the AP 102 is configured so that while a transmission operation is being performed on one link, a reception operation on the other link cannot be performed. Note that using the 2.4 GHz band and the 5 GHz band is merely an example, and the following discussion can also be applied to other combinations of frequency bands. The following discussion can also be applied similarly when two or more different channels of the same frequency band are used. For example, the AP 102 may be configured to function as two access points to establish wireless links and communicate in each of the two frequency bands. For example, the AP 102 may be configured to be capable of communicating in each frequency band using two physically separated communication circuits, or may be configured to be capable of communicating in each frequency band using one physically separated communication circuit but two logically separated communication circuits. Here, the AP 102 determines the link formed by the 2.4 GHz band channel as the primary link, and executes processing to connect the STA 103 attempting to connect via the primary link.

[0030] Each of the following processes is started, for example, when the AP 102 and the STA 103 are powered on. Alternatively, this process may be started in response to a command to start multilink communication from a user or an application in at least one of the AP 102 and the STA 103. Alternatively, this process may be started in response to the amount of data to be communicated with the other device in at least one of the AP 102 and the STA 103 reaching or exceeding a predetermined threshold. The following processes may be realized, for example, by the control unit 202 of the AP 102 (and the STA 103) executing a program stored in the storage unit 201.

[0031] <Processing example 1> FIG. 4 shows a first example of the flow of processing executed when a connection is established between AP 102 and STA 103. In this processing, when AP 102 receives a Probe Request frame from a predetermined STA over a non-primary link, it transmits a Probe Response frame to instruct STA 103 to switch the operating channel. Here, the predetermined STA is, for example, a STA that operates over a single link conforming to a standard older than IEEE 802.11be, such as IEEE 802.11ax, or a STA that complies with IEEE 802.11be and can only operate over a single link. In the following, STA 103 is assumed to be a STA that operates over a single link and operates in the 5 GHz band.

[0032] First, the STA 103 transmits a Probe Request frame including a Multi Band element indicating supported frequency bands and channel information (S401), requesting information (e.g., capability information) from the AP 102. It is assumed that the STA 103 transmits a Probe Request frame in which the 2.4 GHz band is set as the supported frequency band information.

[0033] When the AP 102 receives the Probe Request frame, it analyzes the frame. Then, the AP 102 determines whether the STA 103 can operate on the primary link channel (2.4 GHz band) from the information in the Multi Band element. In this case, the AP 102 determines that the STA 103 can operate on the primary link channel. Therefore, the AP 102 generates a Probe Response frame including an information element for switching the operating channel of the STA 103 to the primary link channel, and transmits the Probe Response frame to the STA 103 (S402). This information element is, for example, a Channel Switch Announcement element.

[0034] Upon receiving this Probe Response frame, the STA 103 switches its operating frequency band from the 5 GHz band to the 2.4 GHz band and starts operating on the channel of the primary link (S403). Then, a wireless link establishment process is executed between the AP 102 and the STA 103 in the 2.4 GHz band (S404). In the link establishment process, an Authentication Request frame and an Authentication Response frame for authentication are exchanged between the AP 102 and the STA 103. An Association Request frame and an Association Response frame for connection processing are also exchanged between the AP 102 and the STA 103. In this process example, the AP 102 completes the connection process by transmitting to the STA 103 an Association Response frame with SUCCESS set as the status code indicating the connection result, indicating a successful connection. After the link establishment process is completed, for example, the STA 103 becomes able to transmit a data frame (S405). 4, before executing the link establishment process (S404), the AP 102 switches the operating channel of the STA 103 to the channel of the primary link, thereby enabling the AP 102 to establish a connection with the STA 103 on the channel of the primary link.

[0035] <Processing example 2> Next, a second example of the flow of processing executed when a connection is established between the AP 102 and the STA 103 will be shown using Figure 5. In this processing example, when the AP 102 receives a Probe Request frame from the STA 103 via a non-primary link, it does not respond with a Probe Response frame. If the STA 103 does not receive a Probe Response frame, it changes its operating frequency and retransmits the Probe Request frame on a channel in a different frequency band. This allows the AP 102 to transition the operating frequency of the STA 103 to the frequency band of the primary link, enabling the establishment of a connection on the channel of the primary link.

[0036] In this process, the STA 103 transmits a Probe Request frame including a Multi Band element indicating supported frequency bands and channel information in the 5 GHz band, which is the operating frequency band (S501). S501 is the same as S401 in FIG. 4. The AP 102 analyzes this Probe Request frame and recognizes from the information in the Multi Band element that the STA 103 can operate on the primary link channel. The AP 102 then refrains from responding with a Probe Response frame in order to transition the operating frequency of the STA 103 to the 2.4 GHz band.

[0037] For example, if the STA 103 fails to receive a Probe Response frame in the 5 GHz band within a predetermined period after transmitting a Probe Request frame, the STA 103 switches the operating channel to the 2.4 GHz frequency band (S502). Then, the STA 103 transmits a Probe Request frame in the 2.4 GHz band, including a Multi Band element indicating supported frequency bands and channel information (S503). Here, information indicating the 5 GHz band is set as the supported frequency band information. As a result, the AP 102 receives the Probe Request frame in the 5 GHz band, which is the primary link.

[0038] When the AP 102 receives a Probe Request frame on the primary link, it transmits a Probe Response frame to permit the STA 103 to connect (S504). Then, a link establishment process is executed (S505), and data is transmitted and received (S506). These processes are the same as S404 and S405 in FIG. 4. In this way, in the example of FIG. 5, the AP 102 switches the operating channel of the STA 103 to the channel of the primary link before executing the link establishment process (S505). This allows the AP 102 to establish a connection with the STA 103 on the channel of the primary link.

[0039] <Processing example 3> In the above-described process examples 1 and 2, the operating frequency of the STA 103 is changed before the link establishment process. However, the operating frequency can also be changed after the link establishment process. In this process example, such a process will be described with reference to FIG. 6. In this process, the STA 103 transmits an Association Request frame via a non-primary link. In response to receiving this Association Request frame, the AP 102 first establishes a connection and then transmits a Probe Response frame to the STA 103 to instruct the STA 103 to switch its operating channel. As a result, after the connection is established, the AP 102 shifts the operating frequency of the STA 103 to the frequency band of the primary link, enabling communication to be performed on the channel of the primary link. Note that in this process example, it is assumed that the AP 102 and the STA 103 transmit and receive Probe Request frames and Probe Response frames before the link establishment process.

[0040] In this process, the AP 102 and the STA 103 first perform authentication processing over a non-primary link. That is, the STA 103 transmits an Authentication Request frame to the AP 102 in the 5 GHz band (S601). Then, the AP 102 transmits an Authentication Response frame to the STA 103 in response in the 5 GHz band (S602). Next, the STA 103 transmits an Association Request frame in the 5 GHz band that includes a Multi Band element indicating the frequency bands and channel information that the STA 103 supports, requesting a connection to the AP 102 (S603). Here, information indicating the 2.4 GHz band is set as the supported frequency band information.

[0041] Upon receiving the Association Request frame, the AP 102 analyzes the frame. From the information in the Multi Band element in the frame, the AP 102 recognizes that the STA 103 is capable of operating on the primary link channel (2.4 GHz band). In response, the AP 102 transmits an Association Response frame to the STA 103, in which SUCCESS, indicating a successful connection, is set in the status code indicating the connection result (S604). The AP 102 then transmits a Probe Response frame including a Channel Switch Announcement element to switch the operating channel of the STA 103 to the primary link channel (S605). Upon receiving this Probe Response frame, the STA 103 switches its operating frequency band from the 5 GHz band to the 2.4 GHz band and begins operating on the primary link channel (S606). Data is then transmitted and received between the AP 102 and the STA 103 (S607).

[0042] 6, after executing the link establishment process, the AP 102 switches the operating channel of the STA 103 to the channel of the primary link, thereby enabling the AP 102 to establish a connection with the STA 103 on the channel of the primary link.

[0043] <Processing example 4> In Processing Example 3, a processing flow was described in which a Probe Response frame is transmitted to change the operating frequency of STA 103 after a link is established via a non-primary link. In this processing example, a link via a non-primary link is not established, and STA 103 is made to attempt to establish a link via the primary link. That is, when AP 102 receives an Association Request frame from STA 103 via the non-primary link, it rejects the connection and prompts STA 103 to switch its operating frequency. An example of this processing flow will be described using FIG. 7. Note that in this processing example as well, it is assumed that Probe Request frames and Probe Response frames are transmitted and received between AP 102 and STA 103 before the link establishment processing.

[0044] In this processing example, the AP 102 and the STA 103 first perform authentication processing on a non-primary link (S701, S702). Then, the STA 103 transmits an Association Request frame in the 5 GHz band, including a Multi Band element indicating the frequency bands and channel information supported by the STA 103, to request connection to the AP 102 (S703). These processing steps are the same as those in S601 to S603 in FIG. 6. Upon receiving the Association Request frame, the AP 102 analyzes the frame. From the information in the Multi Band element, the AP 102 determines that the STA 103 can operate on the channel of the primary link. In response, the AP 102 transmits an Association Response frame to the STA 103, with the status code indicating the connection result set to FAIL, indicating a connection failure (S704). This allows the STA 103 to recognize that the connection attempt in the 5 GHz band has failed. In response to this connection failure, the STA 103 switches its operating frequency to the 2.4 GHz band (S705). Thereafter, the AP 102 and the STA 103 execute a link establishment process in the 2.4 GHz band (S706), and after the link is established, transmit and receive data (S707).

[0045] 7, the AP 102 switches the operating channel of the STA 103 to the channel of the primary link during the link establishment process, thereby enabling the AP 102 to establish a connection with the STA 103 on the channel of the primary link.

[0046] (AP102 processing) Next, an example of the flow of processing executed by the AP 102 among the above-mentioned system operations will be described.

[0047] First, referring to FIG. 8, a process will be described in which the AP 102 changes the operating frequency of the STA 103 in response to a Probe Request frame. First, the AP 102 determines whether the channel on which the Probe Request frame is received is the primary link channel (S801). If the AP 102 receives the Probe Request frame on the primary link channel (YES in S801), it generates a Probe Response frame that does not include Channel Switch information (S804). The AP 102 then transmits the generated frame to the STA 103 (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 also be transmitted in S809. On the other hand, if the AP 102 receives a Probe Request frame on a non-primary link channel (NO in S801), it then determines whether the frame includes a Multi Link element (S802). If the AP 102 determines that the frame includes a Multi Link element (YES in S802), it recognizes that the STA supports multi-link communication. In this case, the STA 103 can operate on both the non-primary link channel and the primary link channel. Therefore, the AP 102 sets the primary link channel to the Multi Link element (S803). Then, the AP 102 generates a Probe Response frame that does not include Channel Switch information and transmits it to the STA 103 (S804, S809).

[0048] On the other hand, if the AP 102 determines that the Probe Request frame does not include a Multi-Band element (NO in S802), it recognizes that a STA that is not capable of multi-link communication has transmitted a Probe Request frame on a non-primary link channel. In this case, the AP 102 determines whether the Probe Request frame includes a Multi-Band element (S805). If the AP 102 determines that the Probe Request frame does not include a Multi-Band element (NO in S805), the STA 103 cannot operate on the primary link channel, and the AP 102 terminates the process. In this case, the AP 102 does not transmit a Probe Response frame, and the STA 103 cannot establish a link with the AP 102. On the other hand, if the Probe Request frame includes a Multi-Band element (YES in S805), the AP 102 determines based on that information whether the STA 103 can operate on the primary link channel (S806). If the AP 102 determines that the STA 103 cannot operate on the primary link channel (NO in S806), the AP 102 terminates the process. In this case, too, the AP 102 does not transmit a Probe Response frame, and therefore the STA 103 cannot establish a link with the AP 102. If the AP 102 determines that the STA 103 can operate on the channel of the primary link (NO in S806), it then determines whether the STA 103 supports Channel Switching (S807). If the AP 102 determines that the STA 103 does not support Channel Switching (NO in S807), it cannot transmit an instruction to the STA 103 to change the channel, and therefore ends the process. In this case, too, the AP 102 does not transmit a Probe Response frame, and therefore the STA 103 cannot establish a link with the AP 102. However, in this case, the STA 103 may be able to establish a link with the AP 102 by changing the operating frequency and transmitting a Probe Request frame on the channel of the primary link.

[0049] In S807, for example, when the AP 102 uses a Channel Switch Announcement element for Channel Switch, the AP 102 determines whether the STA 103 supports this. In this case, the AP 102 can make this determination by checking the Spectrum Management bit in the Capability Information field of the Probe Request frame from the STA 103. Also, when the AP 102 uses an Extended Channel Switch Announcement, the AP 102 can determine whether the STA 103 supports this. In this case, the AP 102 can make this determination by checking the Extended Channel Switching bit in the Extended Capabilities field of the Probe Request frame. Also, whether the STA 103 supports Channel Switch may be determined in a different manner using other capability information.

[0050] If the AP 102 determines that the STA 103 supports Channel Switch (YES in S807), it generates a Probe Response frame in which the primary link channel is set in the Channel Switch information (S808). The AP 102 then transmits this generated frame to the STA 103, causing the STA 103 to change its operating frequency to the frequency band of the primary link. This allows the AP 102 to enable the STA 103, which is capable of operating on the primary link channel, to operate on the primary link channel.

[0051] Next, an example of processing when the AP 102 changes the operating frequency of the STA 103 during / after the link establishment processing will be described with reference to FIG. 9. This processing is processing when the AP 102 receives an Association Request frame. First, the AP 102 executes processing to determine a channel for the primary link (S901). In this processing example, the AP 102 determines that a channel in the 2.4 GHz band will be used as the channel for the primary link. Note that if the channel for the primary link is fixed, the processing of S901 may be omitted. Note that the processing to determine the channel for the primary link may also be executed before the processing of S801 in FIG. 8.

[0052] The AP 102 determines whether the channel on which the Association Request frame was received is the primary link channel (S902). If the channel on which the Association Request frame was received is the primary link channel, the AP 102 determines whether the frame includes a Multi Link element (S903). If the frame includes a Multi Link element, the AP 102 determines that the STA 103 supports multi-link communication, and if the frame does not include a Multi Link element, the AP 102 determines that the STA 103 does not support multi-link communication. If the AP 102 determines that the frame includes a Multi Link element (YES in S903), the AP 102 determines whether the STA 103 can operate on the primary link channel (S904). For example, the AP 102 can determine whether the STA 103 can operate on the primary link channel based on capability information of the STA 103 acquired from a frame such as the Association Request frame.

[0053] If the AP 102 determines that the STA 103 cannot operate on the primary link channel (NO in S904), it cannot change the operating frequency of the STA 103 to the frequency band of the primary link and therefore does not allow the connection. That is, the AP 102 rejects the connection by transmitting an Association Response frame with the status code set to FAIL to the STA 103 (S905). On the other hand, if the AP 102 determines that the STA 103 can operate on the primary link channel (YES in S904), it determines whether or not a predetermined connection condition is satisfied (S906). Note that the determination in S906 can also be made when the channel on which the Association Request frame was received is the primary link channel (YES in S902). The connection condition includes, for example, that the number of connected STAs is below the maximum number that the AP 102 can accommodate. That is, for example, when STA 103 connects to AP 102, considering that AP 102 may not be able to provide communication services to STA 103 depending on its capabilities, the connection conditions include a state in which communication services can be provided. If AP 102 determines that the connection conditions are not met (NO in S906), it transmits an Association Response frame with the status code set to FAIL to STA 103 and rejects the connection (S905). On the other hand, if AP 102 determines that the connection conditions are met (YES in S906), it transmits an Association Response frame with the status code set to SUCCESS to STA 103 and permits the connection (S907).

[0054] If the AP 102 determines that the Association Request frame does not include a Multi Link element (NO in S903), it determines whether the frame includes a Multi Band element (S908). If the AP 102 determines that the frame includes a Multi Band element (YES in S908), it determines whether the STA 103 can operate on the primary link channel (S909). If the AP 102 determines that the STA 103 can operate on the primary link channel (YES in S909), it determines whether the STA 103 supports Channel Switch (S910). This determination can be made based on the value set in the Multi Band element. If the AP 102 determines that the STA 103 supports Channel Switch (YES in S910), it determines whether the connection condition is satisfied (S911). If the AP 102 determines in steps S908 to S910 that the STA 103 cannot operate on the channel of the primary link or that the operating frequency of the STA 103 cannot be changed to the frequency of the primary link, the AP 102 transitions the process to step S905 and rejects the connection. The AP 102 also rejects the connection (S905) if it determines that the connection conditions are not satisfied (NO in step S911).

[0055] If the STA 103 is capable of operating on the primary link channel, can change its operating frequency to the primary link channel, and satisfies the connection conditions (YES in S911), the AP 102 allows the STA 103 to connect. The AP 102 transmits an Association Response frame with the status code set to SUCCESS to the STA 103 to permit the connection (S912). The AP 102 then transmits a Probe Response frame with the primary link channel set in the Channel Switch information to the STA 103 (S913). This switches the connection between the AP 102 and the STA 103 to a connection via the primary link.

[0056] In the above process, instead of transmitting an Association Response frame with the status code set to FAIL in S905, the Association Response frame may not be transmitted. In this case, the STA 103 can recognize the connection failure based on the fact that the Association Response frame was not received. In response to this, the STA 103 can change the operating frequency band to the frequency band of the primary link and retransmit an Association Request frame to establish the connection.

[0057] In the above description, the primary link channel is fixed. However, for example, the primary link channel may be dynamically determined in S901. The primary link channel determination process in this case will be described with reference to FIG. 10. In this process, the AP 102 first determines whether the Association Request frame includes a Multi-Band element (S1001). The AP 102 then calculates the number of STAs that can operate in each frequency band, including the STAs currently connected to the AP 102 and the STA 103 that transmitted the frame (S1002, S1003). For example, if the AP 102 determines that the frame includes a Multi-Band element (YES in S1001), it calculates this number based on the capability information of the STAs currently connected to the AP 102 and the Multi-Band element (S1002). On the other hand, if the AP 102 determines that the Association Request frame does not include a Multi-Band element (NO in S1001), it calculates the above number based on the frequency band in which the frame was received (S1003). For example, assume that, among the connected STAs, the number of STAs that can operate in the 2.4 GHz band is three, and the number of STAs that can operate in the 5 GHz band is three. Here, in S1002, if STA 103 supports both the 2.4 GHz band and the 5 GHz band, the number of STAs that can operate in the 2.4 GHz band is calculated to be four, and the number of STAs that can operate in the 5 GHz band is calculated to be four. Also, in S1003, if STA 103 transmits 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 three, and the number of STAs that can operate in the 5 GHz band is calculated to be four. Then, AP 102 sets the channel of the frequency band with the largest number of operable STAs as the channel of the primary link (S1004).

[0058] Here, the AP 102 determines whether the primary link channel set in S1004 has been changed from the previously set primary link channel (S1005). If the primary link channel has not changed (NO in S1005), the AP 102 terminates the process. On the other hand, if the primary link channel has changed (YES in S1005), the AP 102 executes a process to change the operating frequency of a specific STA among the currently connected STAs. The specific STA here may be, for example, a STA that operates on a single link conforming to a standard older than IEEE 802.11be, such as IEEE 802.11ax, or an IEEE 802.11be STA that can only operate on a single link. The AP 102 transmits a Probe Response frame to the specific STA, in which the new primary link channel is set in the Channel Switch information (S1006). Furthermore, for STAs operating on multiple links, the AP 102 updates the primary link channel information included in the Multi Link element of the Beacon frame to the new channel information. In this way, the AP 102 can set an appropriate channel for the primary link depending on the situation.

[0059] Note that, depending on the setting of the primary link channel, there may be cases where it becomes unnecessary to change the operating frequency of STA 103. That is, even if the receiving channel of the Association Request frame is not the primary link channel when it is received, the receiving channel may become the primary link channel by changing the primary link channel. Therefore, for example, depending on the setting of the primary link channel in S901 of FIG. 9, the determination result in S902 may vary.

[0060] Although the above-described embodiment has been described as a method for a wireless LAN conforming to the IEEE 802.11 standard series, the same discussion can be applied to a communication device capable of establishing multiple wireless links. That is, the above-described method can be applied as a control for connecting a communication partner having a predetermined characteristic to one of multiple wireless links. The above-described AP 102 does not necessarily have to be a communication device that cannot simultaneously transmit in one frequency band and receive in another frequency band among two or more frequency bands. That is, the AP 102 may determine a frequency band based on some criteria and perform the above-described process to operate the STA 103 in that frequency band.

[0061] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0062] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0063] 102: Access Point (AP), 103: Station (STA), 301: Probe Request frame analysis unit, 302: Probe Response frame generation unit, 303: Association Request frame analysis unit, 304: Association Response frame generation unit, 305: Primary link management unit

Claims

1. A communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, receiving means for receiving a predetermined signal related to a connection request from another communication device; a control means for controlling a response to the predetermined signal when the predetermined signal is received on a second channel different from the predetermined first channel, in order to connect the other communication device on the first channel; A communication device comprising:

2. the predetermined signal is a Probe Request frame, 2. The communication device according to claim 1, wherein the control means controls the other communication device to transmit a probe response frame including information indicating that the other communication device should switch to the first channel.

3. 3. The communication device according to claim 2, wherein the control means controls the other communication device to transmit the Probe Response frame including information indicating that the other communication device should switch to the first channel when the other communication device is capable of operating on the first channel, and does not perform such control when the other communication device is not capable of operating on the first channel.

4. 4. The communication device according to claim 3, wherein the control means determines whether the other communication device is capable of operating on the first channel based on information contained in the Probe Request frame.

5. 5. The communication device according to claim 2, wherein the control means controls the other communication device to transmit the Probe Response frame including information indicating that the other communication device should switch to the first channel when the other communication device supports channel switching, and does not perform the control when the other communication device does not support channel switching.

6. 6. The communication device according to claim 5, wherein the control means determines whether the other communication device supports channel switching based on information included in the Probe Request frame.

7. 7. The communication device according to claim 2, wherein the information indicating that the channel should be switched to the first channel is a Channel Switch Announcement element or an Extended Channel Switch Announcement element.

8. the predetermined signal is a Probe Request frame, 2. The communication device according to claim 1, wherein the control means performs control to prompt the other communication device to transmit the Probe Request frame on the first channel by not responding to the Probe Request frame received on the second channel.

9. the predetermined signal is an Association Request frame, 2. The communication device according to claim 1, wherein the control means controls the communication device to transmit, to the other communication device, a frame including information indicating that the other communication device should switch to the first channel, after transmitting an Association Response frame including information indicating that the connection has been successful.

10. 10. The communication device according to claim 9, wherein the control means controls the other communication device to transmit an Association Response frame including information indicating a successful connection when the other communication device is capable of operating on the first channel, and controls the other communication device to transmit an Association Response frame including information indicating a failed connection when the other communication device is not capable of operating on the first channel.

11. 11. The communication device according to claim 10, wherein the control means determines whether the other communication device is capable of operating on the first channel based on information included in the association request frame.

12. 12. The communication device according to claim 9, wherein the control means controls the other communication device to transmit an Association Response frame including information indicating a successful connection when the other communication device supports channel switching, and controls the other communication device to transmit an Association Response frame including information indicating a failed connection when the other communication device does not support channel switching.

13. 13. The communication device according to claim 12, wherein the control means determines whether the other communication device supports channel switching based on information included in the association request frame.

14. 14. The communication device according to claim 9, wherein the frame including the information indicating that switching to the first channel should be performed is a Probe Response frame.

15. 15. The communication device according to claim 14, wherein the information indicating that the channel should be switched to the first channel is a Channel Switch Announcement element or an Extended Channel Switch Announcement element.

16. the predetermined signal is an Association Request frame, 2. The communication device according to claim 1, wherein the control means performs control to prompt the other communication device to transmit the Association Request frame on the first channel by not responding to the Association Request frame received on the second channel.

17. 17. A communication device according to claim 1, further comprising a determining means for determining the first channel from a plurality of channels that can be used by the communication device.

18. 18. The communication device according to claim 17, wherein the determining means determines the first channel based on the number of other devices connected to the communication device that can operate on each of the plurality of channels and the channels on which the other communication devices can operate.

19. 18. The communication device according to claim 17, wherein the determining means determines the first channel based on the number of other devices connected to the communication device that are capable of operating on each of the plurality of channels and the channel on which the predetermined signal is received.

20. 20. The communication device according to claim 18 or 19, characterized in that, when the first channel is changed, the control means further controls the other device to be connected to transmit information indicating that the other device should switch to the changed first channel.

21. 21. The communication device according to claim 18, wherein the control means further performs control to transmit a Beacon frame including the changed first channel when the first channel is changed.

22. The communication device described in any one of claims 1 to 21, characterized in that the communication device is capable of communicating using both the first channel and the second channel, but is unable to receive on either the first channel or the second channel while transmitting on the other of the first channel or the second channel.

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

24. A control method executed by a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, comprising: receiving a predetermined signal relating to a request for connection from another communication device; When the predetermined signal is received on a second channel different from the predetermined first channel, controlling a response to the predetermined signal to connect the other communication device on the first channel; A control method comprising:

25. A program for causing a computer to function as the communication device according to any one of claims 1 to 22.

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