Communication device, control method therefor, and program

Abstract

A communication apparatus, a control method thereof, and a program are disclosed. In a case where a beacon frame is transmitted through a first frequency channel, and in a case where one of a multi-link communication non-supporting apparatus and a multi-link communication supporting communication apparatus establishes connection through a second frequency channel during the communication apparatus establishes connection with the multi-link communication supporting apparatus through the first frequency channel, a frequency channel for transmitting the beacon frame is switched from the first frequency channel to the second frequency channel.

Description

TECHNICAL FIELD

[0001] The present application relates to control of frequency channels for transmission of beacons in wireless communication. BACKGROUND

[0002] Standards for wireless local area network (LAN) technology are established by the Institute of Electrical and Electronics Engineers (IEEE) 802.11, which belongs to a wireless LAN technology standardization group, and standards for wireless LAN technology include IEEE 80.111 / a / b / g / n / ac / ax.

[0003] In IEEE 802.11 discussed in Patent Literature 1, a peak throughput of up to 9.6 Gbps and an increase in communication speed in a crowded situation are realized by orthogonal frequency division multiple access (OFDMA).

[0004] In order to further increase the throughput, a task group that establishes standards for IEEE 802.11be, which is a subsequent standard to IEEE 802.11ax, is established.

[0005] Generally, an access point (AP) of IEEE 802.11 establishes a connection with a station (STA) through a single frequency channel and communicates. In the IEEE 802.11be standard, a technology is being studied in which one AP is able to establish a connection with a STA through a plurality of frequency channels including a 2.4 GHz band, a 5 GHz band, and a 6 GHz band, and is able to communicate.

[0006] LIST OF CITATIONS

[0007] PATENT LITERATURE

[0008] PTL 1: Japanese Patent Publication No. 2018-50133 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] In the IEEE 802.11be standard, a technology is being studied in which an AP is able to establish a connection with a STA through a plurality of frequency channels and is able to communicate; however, in a case where the AP transmits a beacon frame through a plurality of frequency channels, power consumption and processing load increase.

[0011] Therefore, transmission of beacon frames through only representative frequency channels is being studied. However, for example, when an AP transmits a beacon frame through only a first frequency channel and communicates with a first communication device, in a case where the AP establishes a connection with a second communication device through a second frequency channel, the second communication device cannot receive the beacon frame. When the second communication device cannot receive the beacon frame, the second communication device, for example, cannot acquire basic information for synchronization, and cannot perform synchronization. Furthermore, in a case where a communication device uses a power saving function, the communication device cannot acquire the above-described basic information, and cannot know a timing at which the communication device returns from a power saving state.

[0012] The present application aims at preventing occurrence of a communication device that cannot receive a beacon frame when communication through a plurality of frequency channels is performed.

[0013] Problem solution

[0014] To achieve the above object, a communication device according to the present application is a communication device that establishes a connection with another communication device through a first frequency channel and a second frequency channel, and includes a transmission unit configured to transmit a beacon frame including first frequency channel information and second frequency channel information, the first frequency channel information being information of communication through the first frequency channel, the second frequency channel information being information of communication through the second frequency channel, and a switching unit configured to, in a case where the transmission unit transmits the beacon frame through the first frequency channel, and in a case where a second other communication device establishes a connection with the communication device through the second frequency channel during a period in which a first other communication device that recognizes the first frequency channel information and the second frequency channel information establishes a connection with the communication device through the first frequency channel, switch a frequency channel for transmission of the beacon frame from the first frequency channel to the second frequency channel.

[0015] Advantageous effects of the invention

[0016] According to the present application, when communication through a plurality of frequency channels is performed, communication can be performed while preventing occurrence of a communication device that cannot receive a beacon frame. BRIEF DESCRIPTION OF DRAWINGS

[0017] [ Figure 1 ] Figure 1 is a schematic diagram illustrating a configuration of a network to which the communication device 102 belongs.

[0018] [ Figure 2 ] Figure 2 is a schematic diagram illustrating a functional configuration of each of the communication devices 102 to 106.

[0019] [ Figure 3 ] Figure 3is a diagram illustrating a hardware configuration of each of the communication apparatuses 102 to 106.

[0020] [ Figure 4 ] Figure 4 is a flowchart related to the process of transmitting a beacon frame by the communication apparatus 102.

[0021] [ Figure 5 ] Figure 5 is a flowchart for determining a frequency channel for transmitting a beacon frame.

[0022] [ Figure 6 ] Figure 6 is a sequence chart in a case where the communication apparatus 103 that supports multi-link communication establishes a connection after the communication apparatus 102 determines a frequency channel for transmitting a beacon frame.

[0023] [ Figure 7 ] Figure 7 is a sequence chart in a case where the communication apparatus 103 that supports multi-link communication establishes a connection, and then the communication apparatus 104 that belongs to a multi-link communication non-support apparatus establishes a connection.

[0024] [ Figure 8 ] Figure 8 is a sequence chart in a case where the communication apparatus 104 that belongs to a multi-link communication non-support apparatus establishes a connection, and then the communication apparatus 105 that belongs to a multi-link communication non-support apparatus establishes a connection.

[0025] [ Figure 9 ] Figure 9 is a diagram illustrating an example of a frame format that exemplifies a multi-link performance element. DETAILED DESCRIPTION

[0026] Exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. The configurations described in the following exemplary embodiments are merely illustrative, and the present application is not limited to the illustrated configurations.

[0027] Figure 1 A network configuration constituted by the communication apparatus 102 in the present exemplary embodiment is exemplified. The communication apparatus 102 is an access point (AP) having a function of constituting a network 101. The network 101 including the communication apparatus 102 and the communication apparatuses 103 to 106 is exemplified. The communication apparatus 102 and the communication apparatuses 103 and 106 support the IEEE 802.11be standard, and are capable of performing communication conforming to the IEEE 802.11be standard through the network 101.

[0028] Further, the communication apparatuses 102, 103, and 106 establish connections through a plurality of frequency channels in a plurality of frequency bands, and are capable of multi-link communication. The plurality of frequency bands indicates a sub-GHz frequency band, a 2.4 GHz frequency band, a 3.6 GHz frequency band, a 4.9 GHz frequency band, a 5 GHz frequency band, a 60 GHz frequency band, and a 6 GHz frequency band. For example, the communication apparatus 102 can establish a connection with the communication apparatus 103 through a first frequency channel of the 2.4 GHz frequency band and can establish a connection with the communication apparatus 103 through a second frequency channel of the 5 GHz frequency band, and can communicate through these two connections. In this case, the communication apparatus 102 maintains the connection through the second frequency channel in parallel with the connection through the first frequency channel. Further, the established connection can be referred to as a link. In addition, the communication apparatus 102 can not establish connections in different frequency bands but establish a plurality of connections through different frequency channels in the same frequency band.

[0029] Further, the communication apparatuses 102, 103, and 106 can communicate through frequency band widths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0030] In contrast, each of the communication apparatuses 104 and 105 does not support multi-link communication (hereinafter, referred to as a multi-link communication non-support apparatus). The multi-link communication non-support apparatus can be a communication apparatus that supports the IEEE 802.11a / b / g / n / ac / ax standards, or a communication apparatus that supports the IEEE 802.11be standard but does not support multi-link communication.

[0031] In the present exemplary embodiment, each of the communication apparatuses 102, 103, and 106 includes one or more wireless local area network (LAN) control units. In a case where each of the communication apparatuses 102, 103, and 106 includes two or more wireless LAN control units, each of the communication apparatuses 102, 103, and 106 can simultaneously transmit / receive frames by using a plurality of frequency channels. The diagram is illustrative, and the following discussion can be applied to, for example, a network including a large number of communication apparatuses in a wider area or a positional relationship of various communication apparatuses, but is not limited thereto.

[0032] Figure 2 A functional configuration of each of the communication apparatuses 102 to 106 according to the present exemplary embodiment is exemplified. Each of the communication apparatuses 102 to 106 includes wireless LAN control units 201 and 208, a frame generation unit 202, a wireless LAN management unit 203, a user interface (UI) control unit 204, and wireless antennas 207 and 209.

[0033] The wireless LAN control units 201 and 208 are each configured to include a circuit for transmitting or receiving a wireless signal to or from another communication apparatus and a program for controlling the circuit. The wireless LAN control units 201 and 208 each control wireless communication in accordance with the IEEE 802.11 series standards based on a frame generated by the frame generation unit 202 described below. The wireless LAN control units 201 and 208 each control a wireless signal with another communication apparatus in the 2.4 GHz band, the 5 GHz band, and the 6 GHz band.

[0034] The number of wireless LAN control units is not limited to 2 and can be 1 or 3 or no limit. In a case where 1 wireless LAN control unit is provided, the wireless LAN control unit can be used in a time-divided manner to transmit / receive frames of a plurality of frequency channels. The number of wireless antennas provided is consistent with the number of wireless LAN control units.

[0035] The frame generation unit 202 generates a wireless LAN control frame to be transmitted by at least one of the wireless LAN control units 201 and 208. The wireless LAN control frame generated by the frame generation unit 202 can be generated based on a setting stored in the storage unit 301 described below. Also, in addition to or instead of this, the wireless LAN control frame can be generated based on a user setting input by a user.

[0036] The wireless LAN management unit 203 manages frequency channels supported by the communication apparatuses 102 to 106. For example, in a case where the wireless LAN control unit 201 supports the 2.4 GHz band and the wireless LAN control unit 208 supports the 6 GHz band, the wireless LAN management unit 203 manages and shares these frequency channels with the frame generation unit 202.

[0037] In the communication apparatus 102, the wireless LAN management unit 203 manages a connection state of a communication apparatus with which a connection is currently established. The connection state includes information on the number of communication apparatuses connected through which frequency channel and information on whether the communication apparatus with which a connection is established is a multi-link communication non-supporting apparatus. The frequency channels supported by each of the wireless LAN control units can be determined by the communication unit 306 and the wireless antennas 307 and 308 described below and can be limited by a setting stored in the storage unit 301. Alternatively, the frequency channels supported by each of the wireless LAN control units can be changed by a user setting through the UI control unit 204.

[0038] The UI control unit 204 is configured to include a touch panel or UI-related hardware (e.g., a key) for receiving a user's operation of the communication apparatus, and a program that controls the touch panel and the hardware. The UI control unit 204 has a function of presenting information to the user, for example, a function of displaying an image or outputting sound.

[0039] Figure 3 A hardware configuration of each of the communication apparatuses 102 to 106 according to the present exemplary embodiment is exemplified. The communication apparatus 102 includes a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 306, and wireless antennas 307 and 308.

[0040] The storage unit 301 includes one or more memories such as a read only memory (ROM) and a random access memory (RAM), and stores programs for performing various operations described below and various information such as a communication parameter for wireless communication. In addition to the memories such as the ROM and the RAM, a storage medium such as a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a compact disc read only memory (CD-ROM), a compact disc recordable (CD-R), a magnetic tape, a non-volatile memory card, and a digital versatile disc (DVD) can be used as the storage unit 301. Furthermore, the storage unit 301 can include a plurality of memories and the like.

[0041] The control unit 302 includes a processor such as a central processing unit (CPU) and a micro processing unit (MPU), an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), and the like.

[0042] The control unit 302 controls the entire AP or STA by executing the programs stored in the storage unit 301. The control unit 302 can control the entire AP or STA in cooperation with the programs stored in the storage unit 301 and an operating system (OS).

[0043] Furthermore, the control unit 302 controls the function unit 303 to perform a predetermined process such as imaging, printing, and projection. The function unit 303 is hardware that causes the AP or STA to perform a predetermined process. For example, in a case where the AP or STA is a camera, the function unit 303 is an imaging unit, and performs an imaging process. In a case where the AP or STA is a printer, the function unit 303 is a printing unit, and performs a printing process. Furthermore, for example, in a case where the AP or STA is a projector, the function unit 303 is a projection unit, and performs a projection process. Data processed by the function unit 303 can be data stored in the storage unit 301, or data communicated with another AP or STA through the communication unit 306 described below.

[0044] The input unit 304 receives various operations from a user. The output unit 305 performs various outputs to the user through a monitor screen and a speaker. The output of the output unit 305 can be a display on the monitor screen, a sound output by the speaker, a vibration output, or the like. The input unit 304 and the output unit 305 can be implemented by one module such as a touch panel. Also, the input unit 304 and the output unit 305 can be integrated with or separated from the communication device 102.

[0045] The communication unit 306 controls wireless communication conforming to the IEEE 802.11 series standards. The communication unit 306 controls the wireless antennas 307 and 308 to transmit / receive a signal for wireless communication generated by the control unit 302. In a case where the communication device 102 supports a Near Field Communication (NFC) standard, In a case where the communication device 102 performs wireless communication conforming to a plurality of communication standards, a communication unit and a wireless antenna corresponding to each communication standard can be respectively provided. The communication device 102 communicates data such as image data, document data, and video data with each of the communication devices 103, 104, 105, and 106 through the communication unit 306. At least one of the wireless antennas 307 and 308 can be integrated with or separated from the communication unit 306. Also, each of the wireless antennas 307 and 308 can include one or a plurality of physical antennas to perform Multi-Input and Multi-Output (MIMO) transmission / reception.

[0046] Each of the communication devices 102 to 106 operates each unit by using power supplied from an external power source or a built-in battery.

[0047] Figure 4 is a flowchart illustrating a processing flow performed when the control unit 302 executes a program stored in the storage unit 301 of the communication device 102. The flowchart illustrates a processing flow of transmitting a beacon frame.

[0048] In the present exemplary embodiment, the flowchart is started at the time of starting a wireless LAN function, for example, at the time of turning on the communication device 102 or at the time of turning on the wireless LAN function of the communication device 102.

[0049] First, in step S401, the communication device 102 determines a frequency channel for transmitting a beacon frame in a beacon frame transmission channel determination process.

[0050] The frequency channel for transmitting the beacon frame is determined based on information about the frequency channels supported by the AP managed by the wireless LAN management unit 203 of the communication apparatus 102. For example, in a case where the wireless LAN control unit 201 supports the 2.4 GHz band and the wireless LAN control unit 208 supports the 5 GHz band, the communication apparatus 102 can use one frequency channel of the 2.4 GHz band and one frequency channel of the 5 GHz band. In addition, the communication apparatus 102 can also use two frequency channels of the 2.4 GHz band and two frequency channels of the 5 GHz band.

[0051] Further, the communication apparatus 102 can determine the frequency channel for transmitting the beacon frame based on the connection state of the communication apparatus with which the communication apparatus 102 establishes a connection, which is managed by the wireless LAN management unit 203. This will be described below with reference to Figure 5

[0052] After the frequency channel for transmitting the beacon frame is determined, the communication apparatus 102 starts the process for transmitting the beacon frame through the determined frequency channel during the beacon frame interval in step S402. In this example, the beacon frame interval is set to 100 milliseconds; however, the beacon frame interval is not limited thereto.

[0053] In step S403, the communication apparatus 102 monitors the usage state of the frequency channel. In a case where the usage state of the frequency channel has changed (YES in step S403), the process returns to step S401. In a case where the usage state of the frequency channel has not changed (NO in step S403), the process in step S403 is repeated until the end of the process is determined in step S404. During this period, the transmission of the beacon frame is maintained in the frequency channel in which the transmission has been started in step S402.

[0054] In a case where the connection state between the communication apparatus 102 and another communication apparatus changes, the usage state of the frequency channel can be changed. In the present exemplary embodiment, the connection of a new communication apparatus is described as an example of the change of the usage state of the frequency channel; however, the disconnection of the connection with another communication apparatus that has been established can be handled as the change of the usage state of the frequency channel.

[0055] In addition, in a case where the usable frequency channel is changed by a user input, or in a case where the communication apparatus 102 detects that the congestion situation of the surrounding wireless channel has changed, the usage state of the frequency channel can be changed. Thus, with this change as a trigger, the process can return to step S401.

[0056] In step S404, the process ends at the end of the wireless LAN function, for example, at the time when the communication apparatus 102 is turned off or at the time when the wireless LAN function of the communication apparatus 102 is turned off. ​

[0057] In multi-link communication, power consumption and processing load increase when beacon frames are transmitted through all of the frequency channels of the plurality of connections. In other words, the power to be supplied to the communication unit 306 increases, and the processing to be performed in parallel by the control unit 302 increases. Therefore, a representative channel can be selected from the plurality of frequency channels, and a beacon frame including not only information about the representative channel but also information about other frequency channels (non-representative channels) can be transmitted through the representative channel. The representative channel can be referred to as a Primary CH. Thus, each of the communication apparatuses that establish a connection with the communication apparatus 102 can acquire information about non-representative channels together with the beacon frame of the representative channel. The acquired information includes Timing Synchronization Function (TSF) information used for synchronization with the communication apparatus and Traffic Indication Map (TIM) information indicating whether transmission data to each communication apparatus is pending; however, the information is not limited thereto.

[0058] The information about the frequency channels included in the beacon frame can include only information about frequency channels other than the frequency channel through which the beacon frame is transmitted. For example, a beacon frame transmitted in the 2.4 GHz band can include only information about frequency channels of the 5 GHz band, and a beacon frame transmitted in the 5 GHz band can include only information about frequency channels of the 2.4 GHz band. In a case where a plurality of channels in the same 5 GHz band are available, in order to notify availability of different channels in the same band, the beacon frame can include information about frequency channels in the same band.

[0059] The information about the frequency channels can be not only delivered to the beacon frame but also delivered to a Probe Response, an Association Response, or a Reassociation Response transmitted by the communication apparatus 102. Also, each of the communication apparatuses 103 and 106 belonging to the multi-link communication support apparatus can notify the communication apparatus 102 of frequency information that the apparatuses themselves can use through the Probe Response, the Association Response, or the Reassociation Response.

[0060] The frequency channel information can be delivered to the beacon frame by storing the frequency channel information in a multi-link communication support information element such as a multi-link capability element. Also, the frequency channel information can be stored by extending an already existing information element (for example, a Multi-Band Element), and a similar method can be used without being limited thereto.

[0061] Figure 9An example of a frame format of the multi-link capability element is illustrated. In the present example embodiment, Figure 9 The name of the illustrated element is a multi-link capability element; however, the name is not limited thereto, and can be, for example, a multi-link element or other names.

[0062] Each of the communication apparatuses 102, 103, and 106 can detect whether the other communication apparatus is a multi-link communication support apparatus by using the multi-link capability element. Figure 9 The illustrated multi-link capability element notifies the other apparatus of capability information indicating the capability of the own apparatus in multi-link communication. The communication apparatus 102 detects from the received capability information that the communication apparatus is a multi-link communication support apparatus.

[0063] The frame of the multi-link capability element includes an element ID 901, a length 902, and ML capabilities 903. The ML capabilities 903 include common info 904, per band info 905, and per link info 906. The common info 904 is a field indicating common information for all bands and links. Also, the per band info 905 is a field indicating common information for all links included in a specific band, and includes information for each band. Also, the per link info 906 is a field indicating information for each link, and includes information for each link.

[0064] A primary CH 907 included in the common info 904 is a field including information indicating a frequency channel for transmitting / receiving a management frame related to multi-link communication. The management frame indicates a beacon frame, a probe request frame / response frame, an association request frame / response frame, and an action frame.

[0065] In a case where the performance information is represented by the Multi-Link Capability Element, the Per Link Info 906 represents information about a frequency channel through which the transmission apparatus of the Multi-Link Capability Element supports multi-link communication. In this case, the number of channels includes a set of the Per Link Info 906 through which the transmission apparatus of the Multi-Link Capability Element supports multi-link communication. In the present exemplary embodiment, for example, in a case where the communication apparatus 102 supports 1CH (channel) in the 2.4 GHz band and 3CH in the 5 GHz band, the Per Link Info 906 includes two fields, that is, a field for 1CH in the 2.4 GHz band and a field for 3CH in the 5 GHz band. Also, the frequency channel information included in the beacon frame is the information included in the Per Link Info 906, and is information for communication through the frequency channel represented by the frequency channel information included in the beacon frame. The multi-link communication support apparatus can recognize the information included in the Per Link Info 906, but the multi-link communication non-support apparatus cannot recognize the information included in the Per Link Info 906.

[0066] The Link ID 908 included in the Per Link Info 906 is a field including an identifier for identifying a link.

[0067] The Band ID 909 included in the Per Link Info 906 is a field including information for identifying a band. For example, assuming that the Band ID 909 includes values of 0, 1, and 2, the 2.4 GHz band, the 5 GHz band, and the 6 GHz band are the bands corresponding to these values. At this time, for example, in a case where the Band ID 909 has a value of 0, the Per Link Info 906 including the Band ID 909 is information common to the links of the multi-link communication in the 2.4 GHz band. The correspondence relationship between the value included in the Band ID 909 and the content represented by the value is not limited to this. Also, the number of bits of the Band ID 909 can be increased to represent more bands.

[0068] Bandwidth 910 is a field including information indicating the bandwidth of the link indicated by Link ID 908. In a case where the performance information is represented by a multi-link performance element, this field indicates the bandwidth supported by the transmission apparatus of the multi-link performance element in the link indicated by Link ID 908. Bandwidth 910 is a field including performance information indicating the bandwidth supported by the communication apparatus in the frequency band indicated by Band ID 909. For example, assuming that bandwidth 910 includes values of 0, 1, and 2, 20 MHz bandwidth, 40 MHz bandwidth, and 80 MHz bandwidth are displayed as the frequency bandwidths corresponding to these values. At this time, for example, in a case where Band ID 909 has a value of 0, the bandwidth supported by the transmission apparatus of the multi-link performance element in the frequency band indicated by Band ID 909 is 20 MHz. In a case where bandwidth 910 has a value of 1 or more, the transmission apparatus of the multi-link performance element can support all the bandwidths of the value or smaller values thereof when establishing the link of the multi-link communication. For example, in a case where bandwidth 910 has a value of 2, the transmission apparatus supports all 20 MHz, 40 MHz, and 80 MHz as the bandwidth of the link. In each of communication apparatuses 102 and 103, the bandwidth supported in the communication of only one link and the bandwidth supported in the multi-link communication can be different from each other.

[0069] Channel (CH) 911 is a field including information indicating the frequency channel of the link indicated by Link ID 908. This field can include a number directly indicating the channel. Alternatively, CH 911 can include values of 0, 1, 2, and the like, and channels of, for example, 1 CH, 2 CH, and 3 CH can be displayed as the channels corresponding to these values. For example, in a case where CH 911 has a value of 0, the corresponding channel is 1 CH. The correspondence relationship between the value included in CH 911 and the content indicated by the value is not limited to this.

[0070] The process flow when the control unit 302 determines the frequency channel for transmitting the beacon frame by executing the program stored in the storage unit 301 of the communication apparatus 102 in step S401 will be described with reference to Figure 5 The process flow when the control unit 302 determines the frequency channel for transmitting the beacon frame by executing the program stored in the storage unit 301 of the communication apparatus 102 in step S401 will be described with reference to

[0071] First, in step S501, the communication apparatus 102 determines the presence / absence of a communication apparatus with which the communication apparatus 102 has established a connection. The connection state of the communication apparatus is managed by the wireless LAN management unit 203. In step S501, in a case where it is determined that there is no communication apparatus with which a connection has been established (NO in step S501), the frequency channel for transmitting the beacon frame is determined in step S502. In this case, the frequency channel can be determined on the basis of a default setting of the communication apparatus 102, a setting input by a user, or a setting corresponding to the surrounding wireless environment. After the frequency channel for transmitting the beacon frame is determined in step S502, the process ends.

[0072] Further, in step S502, the communication apparatus 102 can change the frequency channel for transmission of the beacon frame to only the plurality of frequency channels set by the user, or determine the channel used by each link, based on the user's setting. In the absence of user input, the default setting held in the storage unit 301 will be used.

[0073] Further, the frequency channel for transmission of the beacon frame can be determined based on the congestion of the surrounding wireless environment. As a method of investigating the congestion, a method of transmitting a probe request in the frequency band and counting the number of response probes, or a method of counting the number of beacon frames received within a predetermined period of time can be considered. Furthermore, a method of aggregating the number of times of carrier sensing within a predetermined period of time, or a method of exchanging information with other communication apparatuses can also be considered; however, the method is not limited thereto.

[0074] In step S501, in the case where it is determined that there is a communication apparatus with which a connection has been established (Yes in step S501), in step S503, it is determined whether only one communication apparatus has established a connection. The number of connected communication apparatuses is also managed by the wireless LAN management unit 203.

[0075] In step S503, in the case where it is determined that only one communication apparatus has established a connection (Yes in step S503), in step S504, it is determined whether the connection is through the frequency channel in which the beacon frame is being transmitted. In step S504, in the case where it is determined that the connection is through the frequency channel in which the beacon frame is being transmitted (Yes in step S504), in step S505, the frequency channel for transmission of the beacon frame is maintained. Then the process ends. In step S504, in the case where it is determined that the connection is not through the frequency channel in which the beacon frame is being transmitted (No in step S504), in step S506, the frequency channel for transmission of the beacon frame is switched to the frequency channel through which the communication apparatus has established a connection. Then the process ends. The case where the connection is not through the frequency channel in which the beacon frame is being transmitted, for example, indicates the case where the communication apparatus 103 has established a connection in the 2.4 GHz band while the communication apparatus 102 is transmitting a beacon frame in the 5 GHz band. In this case, the frequency channel for transmission of the beacon frame will be determined to be the 2.4 GHz band. In step S506, when the frequency channel for transmission of the beacon frame is switched to the frequency channel through which the communication apparatus 103 has established a connection, the transmission of the beacon frame through the frequency channel in which the beacon frame is being transmitted can be maintained. In this case, the beacon frame is transmitted through both frequency channels.

[0076] In step S503, in a case where it is determined that two or more communication apparatuses have established connection (NO in step S503), in step S507, it is determined whether the connection is through the frequency channel on which the beacon frame is being transmitted. In step S507, in a case where it is determined that the connection is through the frequency channel on which the beacon frame is being transmitted (YES in step S507), in step S508, the frequency channel for transmitting the beacon frame is maintained. Then the process ends. In step S507, in a case where it is determined that the connection is not through the frequency channel on which the beacon frame is being transmitted (NO in step S507), in step S509, it is determined whether a multi-link communication non-supporting apparatus has established connection through the frequency channel on which the beacon frame is being transmitted. Note that whether the communication apparatus that has established connection is a multi-link communication non-supporting apparatus is also managed by the wireless LAN management unit 203. In step S509, in a case where it is determined that a multi-link communication non-supporting apparatus has established connection (YES in step S509), in step S510, the frequency channel for transmitting the beacon frame is switched to two frequency channels. Then the process ends. For example, a case where the communication apparatus 102 has established connection with a multi-link communication non-supporting apparatus in the 2.4 GHz band while transmitting a beacon frame in the 2.4 GHz band is described. At this time, in a case where the multi-link communication non-supporting apparatus has also established connection in the 5 GHz band, the beacon frame can be transmitted through two frequency channels. In a case where the communication apparatus 102 has established connection with a multi-link communication supporting apparatus in the 5 GHz band, the beacon frame is transmitted in a similar manner.

[0077] In step S509, in a case where it is determined that a multi-link communication non-supporting apparatus has not established connection (NO in step S509), in step S511, the frequency channel is switched to the frequency channel through which the second or subsequent communication apparatus has established connection. Then the process ends. For example, a case where the communication apparatus 102 has established connection with a multi-link communication supporting apparatus in the 2.4 GHz band while transmitting a beacon frame in the 2.4 GHz band is described. At this time, in a case where a multi-link communication non-supporting apparatus has established connection in the 5 GHz band, the frequency channel for transmitting the beacon frame is switched from the 2.4 GHz band to the 5 GHz band. In a case where the communication apparatus that has established connection in the 5 GHz band is a multi-link communication supporting apparatus, the frequency channel is switched in a similar manner.

[0078] As described above, in a case where the beacon frame is transmitted through one of the frequency channels, communication can be performed while reducing power consumption of the communication apparatus, so as not to generate a communication apparatus that cannot receive the beacon frame. In other words, it is sufficient to supply the communication unit 306 with power required to transmit the beacon frame through one of the frequency channels. This can reduce power consumption compared to a case where the beacon frame is transmitted through a plurality of frequency channels. Also, the control unit 302 does not need to perform processing to transmit the beacon frame in parallel through a plurality of frequency channels. Therefore, the processing load of the control unit 302 can be reduced. Also, a multi-link communication non-supporting apparatus can receive the beacon frame in this case. Therefore, such an apparatus can appropriately perform communication based on the beacon frame, and can perform processing based on the beacon frame.

[0079] A specific example of the processing of the flowchart in Figures 6 to 8 will be described. Figure 5

[0080] Figure 6 is a sequence diagram in a case where the communication apparatus 103 establishes a connection in the 5 GHz band after the communication apparatus 102 determines the frequency channel of the 2.4 GHz band as the frequency channel for transmitting the beacon frame.

[0081] In step S502 after startup, the communication apparatus 102 determines the 2.4 GHz band as the frequency channel for transmitting the beacon frame, and in step S402, the communication apparatus 102 starts transmission of the beacon frame (M6011). Therefore, the communication apparatus 103 starts reception of the beacon frame in the 2.4 GHz band. The beacon frame includes not only the frequency channel information of the 2.4 GHz band but also the frequency channel information of the 5 GHz band. Therefore, the communication apparatus 103 can recognize that the communication apparatus 102 is capable of communicating through the frequency channels of the 2.4 GHz band and the 5 GHz band. In other words, the communication apparatus 103 can detect that the communication apparatus 102 is capable of communicating through the frequency channels of the 5 GHz band by receiving the beacon frame in the 2.4 GHz band. When the communication apparatus 103 transmits a probe request frame by broadcast in the 5 GHz band (M6021), the communication apparatus 102 receives the probe request frame through the frequency channel of the 5 GHz band. In response to the received probe request frame, the communication apparatus 102 transmits a probe response frame (M6022). Therefore, the communication apparatus 103 can detect that the communication apparatus 102 is capable of communicating through the frequency channels of the 5 GHz band. At this time, in a case where the reception of the beacon frame can sufficiently receive the communicable frequency channel information, the probe request frame and the probe response frame can be omitted.

[0082] ​In order to establish a connection with the communication apparatus 102 in the 5 GHz band, the communication apparatus 103 transmits an association request frame (M6023). In response to the received association request frame, the communication apparatus 102 transmits an association response frame (M6024). Thus, the communication apparatus 103 and the communication apparatus 102 can establish a connection through a frequency channel of the 5 GHz band.

[0083] With this connection as a trigger, in step S403, the communication apparatus 102 determines that the usage state of the frequency channel has been changed. The process then returns to step S401. Although the communication apparatus 102 transmits a beacon frame through a frequency channel of the 2.4 GHz band, the communication apparatus 102 can detect that the communication apparatus has connected in the 5 GHz band, and in step S506, can switch the frequency channel for transmitting a beacon frame to a frequency channel of the 5 GHz band.

[0084] Due to the switching, it is sufficient for the communication apparatus 103 to monitor a beacon frame through only a frequency channel of the 5 GHz band. Thus, the communication apparatus 103 is able to maintain communication with low power consumption and low processing load, compared to a case where the communication apparatus 103 receives a beacon frame through a frequency channel of the 2.4 GHz band while communicating through a frequency channel of the 5 GHz band. Also, the communication apparatus 102 is able to maintain communication with low power consumption and low processing load, compared to a case where the communication apparatus 102 transmits a beacon frame through the 2.4 GHz band and the 5 GHz band.

[0085] In order to notify of the switching of the frequency channel for transmitting a beacon frame, the communication apparatus 102 can transmit an action frame (M6012) through the frequency channel in which a beacon frame is being transmitted. Also, the communication apparatus 102 sets the frequency channel for transmitting a beacon frame to the 2.4 GHz band at the time of transmitting M6022; however, the communication apparatus 102 can switch the frequency channel to the 5 GHz band at the time of transmitting M6024 and notify the communication apparatus 103 of the switching of the frequency channel. In this case, upon receiving M6023, the communication apparatus 102 detects the change in the usage state of the frequency channel in step S403, the process returns to step S401, and the communication apparatus 102 changes the frequency channel for transmitting a beacon frame to the 5 GHz band. The frequency channel information in the M6024 frame can be updated from the 2.4 GHz band to the 5 GHz band.

[0086] The communication apparatus 102, which has switched the frequency channel for transmitting a beacon frame, maintains the transmission of a beacon frame through the switched frequency channel (M6025).

[0087] In the present exemplary embodiment, the communication apparatus 103 is a communication apparatus that supports multi-link communication. In a case where a connection is established with the communication apparatus 104 that belongs to a multi-link communication non-supporting apparatus, similar processing can be performed.

[0088] Figure 7 is a sequence chart in a case where the communication apparatus 102 establishes a connection with the communication apparatus 103 supporting multi-link communication, and then the communication apparatus 102 establishes a connection with the communication apparatus 104 belonging to a multi-link communication non-supporting apparatus. As an example, a case will be described in which, after the communication apparatus 102 determines a frequency channel in the 2.4 GHz band as a frequency channel for transmitting a beacon frame, the communication apparatus 103 establishes a connection in the 2.4 GHz band, and then the communication apparatus 104 establishes a connection in the 5 GHz band.

[0089] In step S502 after the start, the communication apparatus 102 determines the 2.4 GHz band as a frequency channel for transmitting a beacon frame, and in step S402, the communication apparatus 102 starts transmission of a beacon frame (M7011). The communication apparatus 103 starts receiving a beacon frame through the frequency channel of the 2.4 GHz band. Since the beacon frame includes frequency channel information of the 5 GHz band, the communication apparatus 103 can recognize that the communication apparatus 102 is capable of communicating through the 2.4 GHz band and the 5 GHz band. In other words, the communication apparatus 103 can detect that the communication apparatus 102 is capable of communicating through the frequency channel of the 5 GHz band by receiving the beacon frame in the 2.4 GHz band. When the communication apparatus 103 transmits a probe request frame by broadcast in the 2.4 GHz band (M7012), the communication apparatus 102 can receive the probe request frame through the frequency channel of the 2.4 GHz band. In response to the received probe request frame, the communication apparatus 102 transmits a probe response frame (M7013). Thus, by receiving the beacon frame of the communication apparatus 102 in the 2.4 GHz band, the communication apparatus 103 can detect that the communication apparatus 102 is capable of communicating through the frequency channel of the 5 GHz band.

[0090] In order to establish a connection with the communication apparatus 102 in the 2.4 GHz band, the communication apparatus 103 transmits an association request frame (M7014). In response to the received association request frame, the communication apparatus 102 transmits an association response frame (M7015). Thus, the communication apparatus 103 and the communication apparatus 102 can establish a connection through the frequency channel of the 2.4 GHz band.

[0091] With this connection as a trigger, the communication apparatus 102 determines in step S403 that the use state of the frequency channel has been changed. The process then returns to step S401. Although the communication apparatus 102 detects that a connection has been established in the 2.4 GHz band, the communication apparatus 102 determines in step S505 that a beacon frame can continue to be transmitted through the frequency channel of the 2.4 GHz band, and maintains the frequency channel for transmitting a beacon frame.

[0092] On the other hand, the communication apparatus 104, which is a non-supporting apparatus of the multi-link communication, transmits a probe request frame by broadcast in the 5-GHz band (M7021). At this time, the communication apparatus 102 can receive the probe request frame through the frequency channel of the 5-GHz band. In response to the received probe request frame, the communication apparatus 102 transmits a probe response frame (M7022). Thus, the communication apparatus 104 detects that the communication apparatus 102 is capable of communication through the frequency channel of the 5-GHz band.

[0093] In order to establish a connection with the communication apparatus 102 in the 5-GHz band, the communication apparatus 104 transmits an association request frame (M7023). In response to the received association request frame, the communication apparatus 102 transmits an association response frame (M7024). Thus, the communication apparatus 104 and the communication apparatus 102 establish a connection through the frequency channel of the 5-GHz band.

[0094] With this connection as a trigger, the communication apparatus 102 determines in step S403 that the use state of the frequency channel has been changed. The process then returns to step S401. Although the communication apparatus 102 transmits a beacon frame through the frequency channel of the 2.4-GHz band, the communication apparatus 102 switches the frequency channel for transmission of the beacon frame to the frequency channel of the 5-GHz band based on the fact that a connection has been established in the 5-GHz band by one communication apparatus.

[0095] As a result of the switching, it is sufficient for the communication apparatus 104 to monitor the beacon frame only through the frequency channel in the 5-GHz band in which the connection has been established.

[0096] In order to notify of the switching of the frequency channel for transmission of the beacon frame, the communication apparatus 102 can transmit an action frame through the frequency channel in which the beacon frame is being transmitted (M7016). The communication apparatus 102 maintains transmission of the beacon frame through the frequency channel for transmission of the beacon frame (M7025). The communication apparatus 103, which has received the action frame (M7016), can continue communication with the communication apparatus 102 by switching the frequency channel for monitoring of the beacon frame from the 2.4-GHz band to the 5-GHz band.

[0097] In the case where the communication apparatus 103 supports the multi-link communication but has established a connection only through the 2.4-GHz band, the communication of the communication apparatus 103 is disconnected as a result of the switching of the frequency channel for transmission of the beacon frame from the 2.4-GHz band to the 5-GHz band. However, the communication apparatus 103 can also detect from the frequency channel information of the beacon frame that the communication apparatus 102 is capable of establishing a connection in the 5-GHz band. Thus, the communication apparatus 103 can also request a connection in the 5-GHz band.

[0098] Figure 8is a sequence chart in a case where the communication apparatus 102 establishes a connection with the communication apparatus 104 belonging to the multi-link communication non-support apparatus, and then the communication apparatus 102 establishes a connection with the communication apparatus 105 belonging to the multi-link communication non-support apparatus. As an example, a case will be described in which the communication apparatus 102 determines a frequency channel in the 2.4 GHz band as a frequency channel for transmitting a beacon frame, the communication apparatus 104 establishes a connection in the 2.4 GHz band, and then the communication apparatus 105 establishes a connection in the 5 GHz band.

[0099] In step S502 after the start, the communication apparatus 102 determines the 2.4 GHz band as a frequency channel for transmitting a beacon frame, and in step S402, the communication apparatus 102 starts transmission of a beacon frame (M8011). The communication apparatus 104 starts receiving a beacon frame through the frequency channel of the 2.4 GHz band. The beacon frame includes not only frequency channel information of the 2.4 GHz band but also frequency channel information of the 5 GHz band. However, since the communication apparatus 104 is a multi-link communication non-support apparatus, the communication apparatus 104 cannot recognize that the communication apparatus 102 is capable of communicating through the frequency channels of the 2.4 GHz band and the 5 GHz band. In such a case, the communication apparatus 104 transmits a probe request frame through broadcast in the 2.4 GHz band (M8012). The communication apparatus 102 can receive the probe request frame through the frequency channel of the 2.4 GHz band. In response to the received probe request frame, the communication apparatus 102 transmits a probe response frame (M8013). Thus, the communication apparatus 104 can detect that the communication apparatus 102 is capable of communicating through the frequency channel of the 2.4 GHz band.

[0100] In order to establish a connection with the communication apparatus 102 in the 2.4 GHz band, the communication apparatus 104 transmits an association request frame (M8014). In response to the received association request frame, the communication apparatus 102 transmits an association response frame (M8015). Thus, the communication apparatus 104 and the communication apparatus 102 can establish a connection through the frequency channel of the 2.4 GHz band.

[0101] With this connection as a trigger, the communication apparatus 102 determines in step S403 that the use state of the frequency channel has been changed. The process then returns to step S401. Although the communication apparatus 102 detects that a connection has been established in the 2.4 GHz band, the communication apparatus 102 determines in step S505 that a beacon frame can continue to be transmitted through the frequency channel of the 2.4 GHz band, and maintains the frequency channel for transmitting a beacon frame.

[0102] On the other hand, when the communication apparatus 105 transmits a probe request frame by broadcast in the 5 GHz band (M8021), the communication apparatus 102 can receive the probe request frame through the frequency channel of the 5 GHz band. In response to the received probe request frame, the communication apparatus 102 transmits a probe response frame (M8022). Thus, the communication apparatus 105 detects that the communication apparatus 102 is capable of communicating through the frequency channel of the 5 GHz band.

[0103] In order to establish a connection with the communication apparatus 102 in the 5 GHz band, the communication apparatus 105 will transmit an association request frame (M8023). In response to the received association request frame, the communication apparatus 102 transmits an association response frame (M8024). Thus, the communication apparatus 105 and the communication apparatus 102 establish a connection through the frequency channel of the 5 GHz band.

[0104] With this connection as a trigger, the communication apparatus 102 determines in step S403 that the usage state of the frequency channel has been changed. The process then returns to step S401. The communication apparatus 102 detects that a connection has been established with the multi-link communication non-supporting apparatus through the frequency channel of the 2.4 GHz band and the frequency channel of the 5 GHz band. Thus, in step S510, the communication apparatus 102 switches the frequency channel for transmitting a beacon frame to the frequency channel of the 2.4 GHz band and the frequency channel of the 5 GHz band.

[0105] As a result of the switching, it is sufficient for the communication apparatuses 104 and 105 to monitor the beacon frame only through the respective frequency channel through which the connection has been established.

[0106] As described above, the communication apparatus 102 according to the present exemplary embodiment can prevent the occurrence of a communication apparatus that cannot receive a beacon frame by switching the frequency channel for transmitting a beacon frame.

[0107] Note that a recording medium storing a program code that can realize the above-described functions can be provided to a system or an apparatus, and a computer (central processing unit (CPU) or micro processing unit (MPU)) of the system or the apparatus can read and execute the program code stored in the recording medium. In this case, the program code read out from the storage medium itself can realize the functions of the above-described exemplary embodiments, and the storage medium storing the program code can be configured as the above-described apparatus.

[0108] Examples of the storage medium for providing the program code include a floppy 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 ROM, and a DVD.

[0109] Furthermore, the above-described functions can be realized not only by the computer executing the read program code but also by causing an operating system (OS) running in the computer to perform part or all of the actual processing based on the instructions of the program code.

[0110] Moreover, the program code read from the storage medium can be written into a memory included in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Moreover, a CPU provided in the function expansion board or the function expansion unit can perform part or all of the actual processing based on the instructions of the program code, thereby realizing the above-described functions.

[0111] The present application can be implemented by providing a program for realizing one or more functions of the above-described exemplary embodiments to a system or an apparatus via a network or a storage medium, and causing one or more processors in a computer of the system or the apparatus to read and execute the program. Moreover, the present application can be implemented by a circuit (for example, an ASIC) that realizes one or more functions.

[0112] The present application is not limited to the above-described embodiments, and various changes and modifications can be made within the spirit and scope of the present application. Therefore, the following claims are presented to inform the public of the scope of the present application.

[0113] This application claims the benefit of Japanese Patent Application No. 2020-048199, filed March 18, 2020, which is hereby incorporated by reference herein in its entirety.

Claims

1. A communication device that establishes a connection with another communication device via a first frequency channel and a second frequency channel, the communication device comprising: The transmission unit is configured to transmit a beacon frame including first frequency channel information and second frequency channel information, wherein the first frequency channel information is information communicated through the first frequency channel and the second frequency channel information is information communicated through the second frequency channel. as well as A switching unit is configured to switch the frequency channel used for transmitting the beacon frame from the first frequency channel to the second frequency channel when the transmission unit transmits the beacon frame through the first frequency channel, and when a second other communication device establishes a connection with the communication device through the second frequency channel during the period when the communication device establishes a connection with the first other communication device through the first frequency channel, wherein the first other communication device identifies the first frequency channel information and the second frequency channel information included in the beacon frame.

2. The communication device according to claim 1, wherein, When the transmission unit transmits the beacon frame through the first frequency channel, and when the second other communication device establishes a connection with the communication device through the second frequency channel during the period when the communication device establishes a connection with the third other communication device through the first frequency channel, the communication device transmits the beacon frame through the first frequency channel and the second frequency channel, and the third other communication device does not recognize the first frequency channel information and the second frequency channel information included in the beacon frame.

3. The communication device according to claim 1, wherein, When the transmission unit transmits the beacon frame through the first frequency channel, and when the second other communication device establishes a connection with the communication device through the first frequency channel while the first other communication device establishes a connection with the communication device through the first frequency channel, the switching unit does not switch the frequency channel used for transmitting the beacon frame, and the transmission of the beacon frame through the first frequency channel is maintained.

4. The communication device according to any one of claims 1 to 3, wherein, The first frequency channel information and the second frequency channel information are transmitted to the beacon frame by storing them in a multi-link performance element or a multi-band element.

5. The communication device according to claim 1, in, The information communicated via the first frequency channel includes information for synchronizing the other communication devices via the first frequency channel, and The information communicated via the second frequency channel includes information for synchronizing the other communication devices via the second frequency channel.

6. The communication device according to claim 5, wherein, The information being synchronized is the Timed Synchronization Function (TSF).

7. The communication device according to claim 1, wherein, The communication device operates as an access point conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11be standard.

8. A control method for a communication device, wherein the communication device establishes a connection with another communication device via a first frequency channel and a second frequency channel, the method comprising: The transmission includes beacon frames containing first frequency channel information and second frequency channel information. The first frequency channel information is information used for communication through the first frequency channel, and the second frequency channel information is information used for communication through the second frequency channel. as well as When the beacon frame is transmitted through the first frequency channel, and when a second other communication device establishes a connection with the communication device through the second frequency channel while the communication device establishes a connection with the first other communication device through the first frequency channel, the frequency channel used for transmitting the beacon frame is switched from the first frequency channel to the second frequency channel, and the first other communication device identifies the first frequency channel information and the second frequency channel information.

9. A computer program product comprising a computer program, wherein, The computer program enables the computer to function as a unit of the communication device according to any one of claims 1 to 7.

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