COMMUNICATION DEVICE, CONTROL METHOD FOR COMMUNICATION DEVICE, AND PROGRAM

Abstract

To determine a frequency band that is appropriately used in multi-link communication.SOLUTION: A communication device conforming to the IEEE802.11 series standard can perform communication in either one communication mode of a first mode for independently performing transmission and reception in respective frequency bands or a second mode for simultaneously performing transmission and reception in the respective frequency bands, and while communicating with the other first communication device by using respective frequency bands of a plurality of frequency bands in the first mode of the second mode, when determining that a predetermined condition related to the communication mode is satisfied, based on the plurality of frequency bands, determines a plurality of frequency bands for performing communication in the communication mode after change, and communicates with the other first communication device in the communication mode after change by using the plurality of determined frequency bands.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to wireless communication technology. [Background technology]

[0002] In recent years, with the development of information and communication technology, Internet usage has been increasing year by year, and various communication technologies are being developed to meet the increasing demand. Among them, Wireless Local Area Network (WLAN) technology has realized an improvement in throughput in Internet communications such as packet data, voice, and video by terminal devices, and various technological developments are currently being actively carried out.

[0003] In the development of WLAN technology, numerous standardization efforts by the Institute of Electrical and Electronics Engineers (IEEE) 802, the standardization organization for WLAN technology, play an important role. The IEEE 802.11 series of standards is known as one of the standard WLAN communication standards, and includes standards such as IEEE 802.11n / a / b / g / ac and IEEE 802.11ax (Patent Document 1). For example, 802.11ax uses OFDMA (orthogonal frequency division multiple access) to achieve a high peak throughput of up to 9.6 gigabits per second (Gbps) as well as improved communication speeds under congested conditions.

[0004] In recent years, a task group called IEEE802.11be was launched as a successor standard aiming to further improve throughput, improve frequency utilization efficiency, and improve communication latency. In IEEE802.11be, multilink technology is being considered, which simultaneously uses multiple frequency bands (wireless channels) in the 2.4GHz, 5GHz, and 6GHz bands to transmit to a single STA (station / terminal device). Conventionally, STAs conforming to the IEEE802.11 standard connected to an AP (access point) and performed data communication with the access point over a single frequency band. With multilink technology, the AP and STA can simultaneously perform data communication over two or more wireless channels, thereby improving throughput. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-50133 A Summary of the Invention [Problem to be solved by the invention]

[0006] There are multiple communication modes for communication using multi-link technology (multi-link communication). For example, there is asynchronous mode, in which the AP and STA transmit and receive independently in multiple frequency bands, and synchronous mode, in which they transmit and receive while synchronized in multiple frequency bands. There is also semi-asynchronous mode, which uses synchronous mode and asynchronous mode depending on the situation.

[0007] In the asynchronous mode, the AP and the STA transmit and receive independently in each frequency band used, and each device (AP, STA) may transmit and receive simultaneously. When the same device transmits and receives simultaneously, if the interval between the frequency bands used for transmission and reception is small, the transmitted signal may be mixed into the receiving circuit as an interference wave, causing interference within the device that adversely affects the receiving characteristics. Therefore, in the asynchronous mode, frequency bands with a small interval that causes interference within the device cannot be used. On the other hand, in the synchronous mode, the AP and the STA transmit or receive simultaneously in each frequency band used. Therefore, frequency bands with a small interval that causes interference within the device can be used. Hereinafter, with regard to the STA, a STA that supports multilink technology is referred to as ML-STA, and a STA that does not support multilink technology is referred to as NonML-STA.

[0008] As described above, the throughput can be improved by multi-link communication, but if the AP and ML-STA do not communicate in an appropriate communication mode, the throughput may decrease. For example, assume that the AP and ML-STA are performing multi-link communication in synchronous mode using multiple frequency bands with small intervals that cause interference within the device. In such a state, when a NonML-STA communicates with an AP using one frequency band, the ML-STA and AP need to perform communication in another frequency band while taking into consideration interference within the device. In other words, in the communication between the ML-STA and the AP using the other frequency band, only transmission is possible when the AP is transmitting to the NonML-STA, and only reception is possible when the AP is receiving. As a result, communication waiting time occurs in the ML-STA, and the throughput decreases.

[0009] In addition, when an AP and an ML-STA are performing multi-link communication in synchronous mode, if data is to be transmitted and received in real time in both directions in an application, the data cannot be transmitted and received simultaneously, which may affect the use of the application.

[0010] The present invention has been made in view of the above problems, and has an object to determine an appropriate frequency band to be used in multi-link communication. [Means for solving the problem]

[0011] As a means for achieving the above object, a communication device according to the present invention has the following configuration: Compliant with IEEE802.11 series standards Multi-link communication is possible Communication Equipment teeth, Multiple Frequency Channels Each frequency channel A first mode in which transmission and reception are performed independently in the Multiple Frequency Channels Each frequency channel a communication means for performing communication in either a first communication mode or a second communication mode for simultaneously performing transmission or reception in the first communication mode; Change of communication mode Change communication mode to process Means, The above After being changed by the communication mode changing means In communication mode 、 The frequency used for communication channel and a determining means for determining The communication means In front In the second mode, multiple frequencies channel Each frequency channel while communicating with a first other communication device using When a connection is established by a second other communication device, the determination means determines frequency channels such that a frequency interval between two adjacent frequency channels among the plurality of frequency channels is equal to or greater than a predetermined interval; The communication means is Frequency Channel Using The first The first communication device communicates with the first other communication device in a mode. Effect of the Invention

[0012] In multi-link communication, it becomes possible to appropriately determine the frequency band to be used. [Brief description of the drawings]

[0013] [Figure 1] 1 shows an example of a network configuration. [Diagram 2] FIG. 2 is a block diagram illustrating an example of a functional configuration of a communication device. [Diagram 3]FIG. 2 is a block diagram illustrating an example of a hardware configuration of a communication device. [Figure 4] FIG. 13 is a conceptual diagram for explaining a frequency interval value required to prevent interference within equipment. [Diagram 5] 11 is a flowchart of a connection process with an ML-STA executed by an AP in the first embodiment. [Figure 6] FIG. 11 is a sequence chart of a connection process executed by an AP and an ML-STA in the first embodiment. [Figure 7] FIG. 4 is a diagram showing frequency intervals of links in the first embodiment. [Figure 8] 11 is a flowchart of a connection process with a NonML-STA executed by an AP in the first embodiment. [Figure 9] FIG. 11 is a sequence chart of a connection process executed by an AP and a NonML-STA in the first embodiment. [Figure 10] FIG. 4 is a conceptual diagram of changing a frequency band of a link in the first embodiment. [Figure 11] 11 is a flowchart of a link frequency band change process executed by an AP in the first embodiment after disconnection of a connection with a NonML-STA. [Figure 12] FIG. 11 is a sequence chart of a process for changing the frequency band of a link after disconnection of a connection with a NonML-STA in the first embodiment. [Figure 13] 13 is a flowchart of a connection process with an ML-STA executed by an AP in the second embodiment. [Figure 14] 13 is a flowchart of a connection process with a NonML-STA executed by an AP in the second embodiment. [Figure 15] FIG. 11 is a sequence chart of a connection process between an AP and a NonML-STA in the second embodiment. [Figure 16] FIG. 11 is a sequence chart of a process of re-changing the operating frequency band based on the type of transmission data in the third embodiment. [Figure 17]FIG. 11 is a sequence chart of a process of re-changing the operating frequency band based on the type of transmission data in the third embodiment. [Figure 18] FIG. 13 is a sequence chart of a process based on the type of transmission data in the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0015] In the following description, frequency channels are those defined in the IEEE 802 series of standards, and the channel numbers in the 2.4 GHz band, 5 GHz band, and 6 GHz band are not limited to those disclosed in this specification and may be any numbers (channels).

[0016] [First embodiment] This embodiment is an embodiment of a process for changing the link to be used to a frequency band that can perform simultaneous transmission and reception when a NonML-STA connects to an AP in a state where the AP and ML-STA are performing multi-link communication in a communication mode including a synchronous mode. As described above, an ML-STA is an STA (station / terminal device) that supports multi-link technology, and a NonML-STA is an STA that does not support multi-link technology. Note that a link refers to a frequency channel (frequency band) that enables data transmission and reception.

[0017] (Configuration of wireless communication system) Fig. 1 shows an example of the configuration of a network in this embodiment. Fig. 1 shows a configuration including an AP (Access Point) 102, an ML-STA 103, and a NonML-STA 104 as communication devices compatible with IEEE802.11be. The AP 102 is a communication device compatible with multi-link technology. The network formed by the AP 102 is indicated by a circle 101. The ML-STA 103 and NonML-STA 104 can transmit and receive signals transmitted and received by the AP 102.

[0018] In this embodiment, as described later with reference to Fig. 2, the AP 102 and the ML-STA 103 are each equipped with multiple wireless LAN control units and can simultaneously transmit and receive frames using multiple frequency bands, whereas the NonML-STA 104 is equipped with one wireless LAN control unit and transmits and receives frames using one frequency band.

[0019] Note that this diagram is just one example, and the following discussion can be applied to a network including a large number of ML-STAs and NonML-STAs in a wider area, and to the positional relationships of various communication devices.

[0020] (Configuration of communication device) Next, the configuration of the communication devices (AP102, ML-STA103, NonML-STA104) in this embodiment will be described. First, the functional configuration of the communication devices will be described with reference to Fig. 2. Fig. 2(a) shows a block diagram of an example of the functional configuration of AP102 and ML-STA103. AP102 and ML-STA103 each include wireless LAN control units 201a, 201b, 201c, a frame generation unit 202, a frame analysis unit 203, a UI (user interface) control unit 204, a frequency band determination unit 205, a multi-link communication control unit 206, and a communication mode control unit 207 as an example of the functional configuration.

[0021] The wireless LAN control units 201a, 201b, and 201c are configured to include a program that performs control for transmitting and receiving wireless signals to and from other wireless LAN devices. The wireless LAN control units 201a, 201b, and 201c execute wireless LAN communication control based on frames generated by the frame generation unit 202 in accordance with the IEEE802.11 standard series. In this embodiment, the wireless LAN control units 201a, 201b, and 201c are each capable of performing communication (communication control) in any one of the 2.4 GHz band, the 5 GHz band, and the 6 GHz band via the antennas 306a, 306b, and 306c (FIG. 3(a)). The number of wireless LAN control units is not limited to three, and may be two, four, or more.

[0022] The frame generation unit 202 generates wireless control frames to be transmitted by the wireless LAN control units 201a, 201b, and 201c. The contents of the wireless control frames generated by the frame generation unit 202 may be restricted by settings stored in the storage unit 301 (FIG. 3(a)). The contents of the wireless control frames may be changed by settings made by the user via the input unit 304 (FIG. 3(a)) and the UI control unit 204.

[0023] Frame analysis unit 203 interprets frames received by wireless LAN control units 201a, 201b, and 201c, and reflects the contents of the frames in wireless LAN control units 201a, 201b, and 201c. Regardless of which wireless LAN control unit receives a frame, by passing the frame through frame analysis unit 203 once, it becomes possible to control a wireless LAN control unit that has not received the frame.

[0024] The UI control unit 204 is configured to include a program that controls the operation of the input unit 304 (FIG. 3(a)) of the AP 102 and the ML-STA 103 by a user (not shown). The UI control unit 204 also has a function for displaying images or the like or presenting information such as audio output to the user via the output unit 305 (FIG. 3(a)). The frequency band determination unit 205 has a function for determining which frequency band is available for data communication. The multilink communication control unit 206 has a function for performing control related to the multilink communication. For example, the multilink communication control unit 206 performs control for determining (including changing or maintaining) multiple frequency bands to be used for communication. The communication mode control unit 207 performs control of the communication mode (synchronous mode, asynchronous mode, etc.). For example, the communication mode control unit 207 determines whether or not a predetermined condition related to the change of the communication mode is satisfied. The synchronous mode is a communication mode in which transmission and reception are performed while being synchronized in multiple frequency bands, and the asynchronous mode is a communication mode in which the AP and the STA perform transmission and reception independently in multiple frequency bands.

[0025] FIG. 2(b) shows a block diagram of a functional configuration example of the NonML-STA 104. The wireless LAN control unit 211 is configured to include a program that performs control for transmitting and receiving wireless signals to and from other wireless LAN devices. The wireless LAN control unit 211 executes wireless LAN communication control based on a frame generated by the frame generation unit 212 in accordance with the IEEE802.11 standard series. In this embodiment, the wireless LAN control unit 211 is assumed to be able to perform communication (communication control) in any of the 2.4 GHz band, the 5 GHz band, and the 6 GHz band via an antenna 316 (FIG. 3(b)). The frame generation unit 212 generates a wireless control frame to be transmitted by the wireless LAN control unit 211. The contents of the wireless control frame generated by the frame generation unit 212 may be restricted by settings stored in the storage unit 311 (FIG. 3(b)). The contents of the wireless control frame may also be changed by settings made by the user via the UI control unit 214. The frame analysis unit 213 interprets the frame received by the wireless LAN control unit 211. The UI control unit 214 is configured to include a program that controls operations on an input unit 314 (FIG. 3(b)) of the NonML-STA 104 by a user (not shown). The UI control unit 214 also has a function for displaying images or other information, such as audio output, to the user via an output unit 315 (FIG. 3(b)). The frequency band determination unit 215 has a function for determining which frequency band is to be made available for data communication.

[0026] Next, the hardware configuration of the communication device will be described with reference to Fig. 3. Fig. 3(a) shows a block diagram of an example of the hardware configuration of AP 102 and ML-STA 103. Here, the description will be given taking AP 102 as an example, but the same description can be applied to ML-STA 103. AP 102 has, as an example of the hardware configuration, a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 307, and antennas 306a, 306b, and 306c.

[0027] The storage unit 301 is configured with both or either one of a ROM and a RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. Note that, in addition to memories such as ROM and RAM, the storage unit 301 may be a storage medium 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, or a DVD.

[0028] The control unit 302 is configured with, for example, a processor such as a CPU or MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc. Here, CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit 302 controls the entire AP 102 by executing a program stored in the storage unit 301. Note that the control unit 302 may control the entire AP 102 in cooperation with the program stored in the storage unit 301 and an OS (Operating System).

[0029] Furthermore, the control unit 302 controls the functional unit 303 to execute predetermined processes such as imaging, printing, and projection. The functional unit 303 is hardware for the AP 102 to execute predetermined processes. For example, if the AP 102 is a camera, the functional unit 303 is an imaging unit and performs imaging processing. For example, if the AP 102 is a printer, the functional unit 303 is a printing unit and performs printing processing. For example, if the AP 102 is a projector, the functional unit 303 is a projection unit and performs projection processing. Data processed by the functional unit 303 may be data stored in the storage unit 301, or may be data communicated with another communication device via a communication unit 307 described later.

[0030] The input unit 304 receives various operations from the user. The output unit 305 outputs various information to the user. Here, the output by the output unit 305 includes at least one of display on a screen, audio output by a speaker, vibration output, and the like. Note that both the input unit 304 and the output unit 305 may be realized by one module, such as a touch panel. Also, the input unit 304 and the output unit 305 may be integrated with the AP 102 or may be separate from it.

[0031] The communication unit 307 controls wireless communication compliant with the IEEE802.11 series of standards and IP communication. In this embodiment, the communication unit 307 can execute processing compliant with at least the IEEE802.11be standard. The communication unit 307 also controls antennas 306a, 306b, and 306c to transmit and receive wireless signals for wireless communication. The AP 102 communicates content such as image data, document data, and video data with other communication devices via the communication unit 307. The communication unit 307 also includes a transmission queue that holds data to be transmitted.

[0032] The antennas 306a, 306b, and 306c are antennas capable of communicating in at least one of the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. In this embodiment, the antennas 306a, 306b, and 306c are assumed to be used for communication by the wireless LAN control units 201a, 201b, and 201c (FIG. 2(a)), respectively. The antennas 306a, 306b, and 306c may each be physically configured with one or more antennas to realize MIMO (Multi-Input and Multi-Output) transmission and reception.

[0033] FIG. 3(b) shows a block diagram of a hardware configuration example of the NonML-STA 104. In FIG. 3(b), the storage unit 311, the control unit 312, the function unit 313, the input unit 314, the output unit 315, and the communication unit 317 are similar to the storage unit 301, the control unit 302, the function unit 303, the input unit 304, the output unit 305, and the communication unit 317 in FIG. 3(a), and therefore the description thereof will be omitted. However, the communication unit 317 does not have to comply with the IEEE802.11be standard. The NonML-STA 104 has one antenna 316. The antenna 316 is an antenna capable of communication in at least one of the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. In this embodiment, the antenna 316 is used for communication by the wireless LAN control unit 211 (FIG. 2(b)). The antenna 316 may be physically composed of one or more antennas to realize MIMO transmission and reception.

[0034] (Processing flow) Next, the flow of processing of each communication device in this embodiment will be described. First, a frequency interval value required to prevent intra-device interference, which is preset in the AP 102 and ML-STA 103 compatible with the multi-link technology, will be described. In the case of multi-link communication in asynchronous mode (when the same device can perform transmission and reception simultaneously), if the frequency interval of each link used for transmission and reception is small, the transmission signal may be mixed into the receiving circuit as an interference wave, causing intra-device interference that adversely affects the reception characteristics. In order to prevent intra-device interference, a frequency interval value required to prevent intra-device interference is set in the AP 102 and ML-STA 103.

[0035] FIG. 4 is a conceptual diagram for explaining a frequency interval value F required to prevent interference within the device. As shown in FIG. 4, the frequency interval value F is a frequency interval value required to prevent interference within the device when two links (Link1 and Link2) are used. In this embodiment, the frequency interval value F for the AP 102 (hereinafter, F AP ) is 200 MHz, and the frequency interval value F for the ML-STA103 (hereinafter, F ML-STA (hereinafter referred to as the "frequency division multiplexing") is set to 300 MHz.

[0036] <Connection Process between AP102 and ML-STA103> Using FIGS. 5 and 6, the connection process (the process until data transmission and reception) between AP102 and ML-STA103 will be described. FIG. 5 shows a flowchart of the connection process between AP102 and ML-STA103 executed by AP102 in the present embodiment, and FIG. 6 shows a sequence chart of the connection process executed by AP102 and ML-STA103 in the present embodiment. As described above, AP102 and ML-STA103 each have wireless LAN control units 201a, 201b, and 201c that can communicate in any of the 2.4 GHz band, 5 GHz band, and 6 GHz band.

[0037] In the present embodiment, the frequency at which AP102 and ML-STA103 communicate a management frame for the connection process is 2.4 GHz, and the connection in other frequency bands is also controlled by this communication. Note that using 2.4 GHz is an example, and the frequency for transmitting and receiving the management frame is not limited to this. The management frame is defined in the IEEE802.11 series of standards and includes Beacon frames, Probe Request / Response, Authentication Request / Response, Association Request / Response, Reassociation Request / Response frames, etc. The generation process of the frame is performed by the frame generation unit 202.

[0038] In FIG. 5, first, the frequency band determination unit 205 of AP102 determines which frequency band to make available (S501). AP102 may make this determination based on the congestion of the surrounding wireless environment, but is not limited to this. In the present embodiment, it is assumed that the 2.4 GHz band, 5 GHz band, and 6 GHz band are available.

[0039] After the frequency bands available for use are determined by the frequency band determination unit 205 of the AP 102, the AP 102 transmits frequency band information using one of the available frequency bands (S502). Here, it is assumed that the wireless LAN control unit 201a transmits using the 2.4 GHz band (in both the AP 102 and the ML-STA 103). The frequency band information includes information on frequency bands available for use by the AP 102, information indicating that the AP 102 supports multi-link communication, and F AP (The same applies to the following explanation.) The wireless LAN control unit 201a of the AP 102, for example, assigns frequency band information to a Beacon frame and transmits it in the 2.4 GHz band (F601). Note that the frequency band information may be assigned not only to the Beacon frame but also to the Probe Response, Authentication Response, Association Response, and Reassociation Response frames transmitted by the AP 102.

[0040] After the AP 102 transmits the frequency band information to the ML-STA 103, the wireless LAN control unit 201a of the ML-STA 103, which has received the Beacon frame, transmits a Probe Request frame at 2.4 GHz and starts a scan operation (F602). The wireless LAN control unit 201a of the ML-STA 103 may add the frequency band information of the ML-STA 103 to the Probe Request frame. The frequency band information may include information on the frequency band that the ML-STA 103 can use, information indicating that the ML-STA 103 supports multi-link communication, and F ML-STA (The same applies to the following description.) The ML-STA 103 may notify the AP 102 of its available frequency information by including it in an Authentication Request, Association Request, or Reassociation Request frame.

[0041] The wireless LAN control unit 201a of the AP 102 that has received the Probe Request frame from the ML-STA 103 transmits a Probe Response frame to the ML-STA 103 (F603). The Probe Response frame may include available frequency information of the AP 102. The frame analysis unit 203 of the ML-STA 103 uses the available frequency information included in the Beacon frame and the Probe Response frame from the AP 102 to detect the frequency supported by the AP 102 and the channel that operates at that frequency.

[0042] Thereafter, the AP 102 and the ML-STA 103 establish a connection by communication via the respective wireless LAN control units 201a (S503, F604, F605). When a secure connection using encryption is to be established between the AP 102 and the ML-STA 103, communication processing such as WPA (Wi-Fi Protected Access), WPA2, and WPA3 may be performed thereafter. Although a connection without encryption is described in this embodiment, the present invention is not limited to this. The AP 102 and the ML-STA 103 may establish a connection using two or more available frequency bands. For example, when there are three available frequency bands, a connection may be established using two or all of them. Hereinafter, a channel (frequency band) that allows data transmission and reception in this way becomes a "link". In this embodiment, 5ch in the 2.4 GHz band, 36ch in the 5 GHz band, and 100ch in the 5 GHz band are regarded as links. In addition, the AP 102 and the ML-STA 103 each have a function of communicating in a maximum 40 MHz band in the 2.4 GHz band, and in a maximum 160 MHz band in the 5 GHz band and 6 GHz band.

[0043] When a connection is established between the AP 102 and the ML-STA 103, the multilink communication control unit 206 of the AP 102 optionally determines transmission and reception parameters (S504, F606). The transmission and reception parameters are information (parameters) for determining how to distribute transmitted and received data to each connection when multiple connections are established. The amount of data to be distributed can be determined, for example, according to the maximum throughput available in each frequency band, or according to the current throughput calculated by actually sending test packets. This value may also be changed at any time. For example, after transmitting and receiving data for a certain period of time, the AP 102 may determine the amount of data to be distributed for the next certain period of time from the amount of data that was actually transmitted and received. Alternatively, the bands for transmitting and receiving control packets and data packets may be divided.

[0044] In addition, when performing multi-link communication, the communication mode control unit 207 of the AP 102 determines the communication mode for each link, that is, whether or not to perform transmission and reception simultaneously between each link. AP (=200MHz) and F ML-STA (=300 MHz), the communication mode control unit 207 determines not to transmit and receive simultaneously using the two links (not to use asynchronous mode). That is, the communication mode control unit 207 can determine to communicate in synchronous mode when the frequency interval between the two links is smaller than the frequency interval required for both the AP 102 and the ML-STA 103 to transmit and receive simultaneously using the two links. Also, the communication mode control unit 207 can determine to communicate in synchronous mode and / or asynchronous mode when the frequency interval between the two links is equal to or larger than the frequency interval. The wireless LAN control unit 201a of the AP 102 notifies the ML-STA 103 of the determination as a transmission / reception parameter (including the transmission / reception parameter).

[0045] Considering the maximum bandwidth available for communication, the frequency interval between links used in multi-link communication in this embodiment is as follows: Fig. 7 shows the frequency interval between links used in multi-link communication in this embodiment. Frequency interval between 5ch and 36ch: 2708MHz Frequency interval between 36ch and 100ch: 160MHz Frequency interval between 5ch and 100ch: 3028MHz These interval values ​​and F AP (=200MHz) and F ML-STA (=300MHz), the frequency interval between 36ch and 100ch is F AP and F ML-STA Therefore, the communication mode control unit 207 of the AP 102 determines to communicate in synchronous mode without performing simultaneous transmission and reception (without using asynchronous mode) between the links of 36ch and 100ch. On the other hand, between the links of 5ch and 36ch and 5ch and 100ch, the frequency interval is F AP , F ML-STA Therefore, the communication mode control unit 207 of the AP 102 determines that simultaneous transmission and reception may be performed between these links (that is, either synchronous mode or asynchronous mode may be used). The wireless LAN control unit 201a of the AP 102 notifies the ML-STA 103 of the determination as a transmission / reception parameter (including it in the transmission / reception parameter).

[0046] Using the transmission and reception parameters, AP102 and ML-STA103 start transmitting and receiving data using multi-link communication (S505, F607~F609, F617~F618, F627~F628). In the example of FIG. 6, the wireless LAN control units 201a of AP102 and ML-STA103 perform multi-link communication using the asynchronous mode at 5ch (2.4 GHz band). Also, the wireless LAN control units 201b of AP102 and ML-STA103 perform multi-link communication using the synchronous mode at 36ch (5 GHz band). Further, the wireless LAN control units 201c of AP102 and ML-STA103 perform multi-link communication using the synchronous mode at 100ch (5 GHz band). Note that for multi-link communication using the synchronous mode, for example, synchronous communication can be realized by AP102 transmitting a trigger frame regarding communication timing to ML-STA103.

[0047] <Connection processing between AP102 and NonML-STA104 and frequency band change processing> Next, with reference to FIGS. 8 and 9, the connection processing between AP102 and NonML-STA104 after AP102 has established multi-link communication with ML-STA103, and the frequency band change processing considering in-device interference by AP102 will be described. FIG. 8 shows a flowchart of the connection processing with NonML-STA104 executed by AP102 in this embodiment, and FIG. 9 shows a sequence chart of the connection processing executed by AP102 and NonML-STA104 in this embodiment. As described above, NonML-STA104 has a wireless LAN control unit 211 that can communicate in any of the 2.4 GHz band, 5 GHz band, and 6 GHz band.

[0048] In Fig. 9, the AP 102 and the ML-STA 103 are assumed to be continuing data transmission and reception (F901, F902, F911, F912, F931, F932) following the data transmission and reception (S505, F607 to F609, F617 to F618, F627 to F628) shown in Fig. 5 and Fig. 6. At this time, the frequency band determination unit 205 of the AP 102 periodically determines which frequency band is to be made available (S801). The AP 102 may make this determination depending on the degree of congestion in the surrounding wireless environment, but is not limited to this. In this embodiment, it is assumed that the 2.4 GHz band, the 5 GHz band, and the 6 GHz band are available.

[0049] In S802, the AP 102 periodically transmits a Beacon frame using one of the available frequency bands (F921). Here, it is assumed that the wireless LAN control unit 201b transmits a management frame including a Beacon frame to the NonML-STA 104 using the 5 GHz band. The wireless LAN control unit 201b assigns frequency band information of the AP 102 to the Beacon frame. The frequency band information is as described above, and may also include information indicating that the AP 102 supports multi-link communication.

[0050] The wireless LAN control unit 211 of the NonML-STA 104 that has received the Beacon frame transmits a Probe Request frame in one of its available frequency bands (5 GHz in this example) (F922) and starts a scan operation. The wireless LAN control unit 211 of the NonML-STA 104 may add frequency band information of the NonML-STA 104 to the Probe Request frame. The frequency band information may include information on frequency bands available to the NonML-STA 104 and information indicating that the NonML-STA 104 does not support multi-link communication. Alternatively, the frequency band information may be configured not to include information indicating that the NonML-STA 104 supports multi-link communication. The NonML-STA 104 may notify the AP 102 of its own frequency information by including it in an Authentication Request, Association Request, or Reassociation Request frame.

[0051] The frame analysis unit 203 of the AP 102 analyzes the available frequency band information of the NonML-STA 104 that is attached to the Probe Request frame from the NonML-STA 104. The frame analysis unit 203 detects that the NonML-STA 104 does not support multilink communication because the frame contains information indicating that the NonML-STA 104 does not support multilink communication (or does not contain information indicating that the NonML-STA 104 supports multilink communication).

[0052] In this example, when the AP 102 is performing multi-link communication in synchronous mode with a STA other than the NonML-STA 104 (i.e., the ML-STA 103), if the NonML-STA 104 connects to the link (36ch) used in the synchronous mode, the communication throughput of the ML-STA 103 will decrease. Therefore, the communication mode control unit 207 of the AP 102 selects a link with a frequency interval of F between one or more adjacent links, such as 36ch. AP (=300MHz) and F ML-STAIf the NonML-STA 104 performs connection processing to a link with a frequency interval smaller than F (=200 MHz), the multilink communication control unit 206 determines that the condition for changing the communication mode is satisfied. AP and F ML-STA The system decides to change the number of links to be used so that the distance between the two links, 36ch and 100ch, is larger than either of the two links, and performs the change process. In this example, as described above, the distance between the two links, 36ch and 100ch, is 160MHz. AP (=300MHz) and F ML-STA (=200 MHz). Therefore, the AP 102 changes to 100ch. In this example, the AP 102 changes to 1ch (center frequency 5945 MHz) in the 6 GHz band, which can secure a 160 MHz bandwidth.

[0053] Fig. 10 shows a conceptual diagram of the change of the frequency band of the link in this embodiment. As shown in Fig. 10, by changing the frequency band of the link, the frequency interval becomes 605 MHz, and F AP and F ML-STA Therefore, the AP102 and the ML-STA103 can simultaneously transmit and receive without interference within the device between the links of 36ch in the 5GHz band and 1ch in the 6GHz band.

[0054] The wireless LAN control unit 201a of the AP 102 transmits a channel switch announcement to the ML-STA 103, notifying the change in the frequency band of the link and the new frequency band (F903). After that, the multi-link communication control unit 206 of the AP 102 and the ML-STA 103 performs control to change the link (F933). Furthermore, the communication mode control unit 207 of the AP 102 determines that in multi-link communication with the ML-STA 103, transmission and reception may be performed simultaneously in any of the links. In other words, the communication mode control unit 207 of the AP 102 determines that communication may be performed in either the synchronous mode or the asynchronous mode. The wireless LAN control unit 201a of the AP 102 notifies the ML-STA 103 of the determination.

[0055] The wireless LAN control unit 201b of the AP102 transmits a Probe Response frame (F923) in response to the Probe Request frame (F922) from the NonML-STA 104. The Probe Response frame includes information on the frequency band available after the link change. The frame analysis unit 213 of the NonML-STA 104 detects the frequency supported by the AP102 and the channel operating at that frequency from the information on the frequency band available after the link change included in the Probe Response frame from the AP102.

[0056] Thereafter, the AP 102 and the NonML-STA 104 establish a connection by communication via the wireless LAN control unit 201b and the wireless LAN control unit 211 (S803, F924, F925). When a secure connection using encryption is to be established between the AP 102 and the NonML-STA 104, communication processing such as WPA, WPA2, and WPA3 may be performed thereafter. In this embodiment, a connection without encryption will be described, but is not limited to this.

[0057] Thereafter, the AP 102 and the ML-STA 103 transmit and receive data using multi-link communication (F904, F905, F913, F914, F934 to F937). Also, the AP 102 and the NonML-STA 104 transmit and receive data using single-link communication in one frequency band (F926).

[0058] <Processing for changing frequency band used after disconnection of STA that does not support multi-link> 11 and 12, a process will be described in which the frequency band used by the AP 102 for multilink communication with the ML-STA 103 is restored to the original state (before the change) after the NonML-STA 104 has disconnected from the AP 102. Even after the NonML-STA 104 has disconnected from the AP 102, the AP 102 can continue to communicate with the ML-STA 103 without changing the frequency band of the link. On the other hand, the AP 102 can restore the frequency band and change to the synchronous mode if the communication situation of the frequency band being used becomes congested or for other reasons.

[0059] Fig. 11 shows a flowchart of the process of changing the frequency band of a link after disconnection with the NonML-STA 104, which is executed by the AP 102 in this embodiment. Also, Fig. 12 shows a sequence chart of the process of changing the frequency band of a link after disconnection with the NonML-STA in this embodiment.

[0060] In Fig. 12, it is assumed that the AP 102, the ML-STA 103, and the NonML-STA 104 are continuing the data transmission and reception (F904, F905, F913, F914, F934 to F937, F926) shown in Fig. 9 and Fig. 10. Here, it is assumed that the NonML-STA 104 disconnects from the AP 102 due to the end of the data transmission and reception. At this time, the wireless LAN control unit 211 of the NonML-STA 104 transmits a De-authentication frame to the AP 102 (F1221). As a result, the AP 102 disconnects from the NonML-STA 104 (S1101).

[0061] Thereafter, data transmission and reception between the AP102 and the ML-STA103 continues (F1201, F1211, F1212, F1231, F1232), while the AP102 can return the frequency band to the original frequency band and change to the synchronous mode as necessary (for example, depending on the congestion of the surrounding wireless environment (communication status) or an input operation by the user). In this example, it is assumed that the communication mode control unit 207 of the AP102 determines that the condition for changing the communication mode is satisfied according to the communication status when the NonML-STA104 disconnects from the AP102. Thereafter, the multilink communication control unit 206 of the AP102 decides to return the frequency band changed in F933 to the original frequency band, and the communication mode control unit 207 decides to change to the synchronous mode. Then, the wireless LAN control unit 201a transmits a channel switch announcement to the ML-STA103 (F1202, S1102). As a result, the AP 102 notifies the ML-STA of the change in link frequency band and the changed frequency band. After that, the multi-link communication control unit 206 of the AP 102 and the ML-STA 103 changes the link (F1233). In this example, the AP 102 returns the link of 1ch in the 6GHz band to 100ch in the 5GHz band. After this, the AP 102 transmits and receives data to and from the ML-STA 103 by multi-link communication (S1103, F1203, F1204, F1213, F1214, F1234, F1235).

[0062] In addition, after AP102 disconnects from NonML-STA104, the multi-link communication control unit 206 may be configured to change the frequency band used regardless of the decision of the communication mode control unit 207, and then the communication mode control unit 207 may be configured to decide the communication mode.

[0063] As described above, in this embodiment, when an AP and an STA that support multi-link communication are performing multi-link communication in the synchronization mode, if an STA that does not support multi-link connects to the AP, the link is changed to a frequency band that can perform transmission and reception simultaneously. This can suppress a decrease in the communication throughput of the STA that supports multi-link communication. In addition, when the STA that does not support multi-link disconnects the connection after connecting to the AP, the procedure when the AP returns based on the frequency band and communicates in the synchronization mode is also described.

[0064] [Second Embodiment] This embodiment is an embodiment regarding the processing when a NonML-STA communicates with an AP in a state where the AP and the ML-STA are performing multi-link communication. Since the configurations of the wireless communication system, the AP102, the ML-STA103, and the NonML-STA104 are the same as those in the first embodiment, the descriptions thereof are omitted. Note that the frequency interval value F required to prevent in-device interference is also the same as that in the first embodiment. That is, the frequency interval value F required to prevent in-device interference between the AP102 and the ML-STA103 is F AP = 200 MHz and F ML-STA = 300 MHz.

[0065] [Connection Process between AP102 and ML-STA103] Using FIGS. 5 and 13, the connection process (the process until data transmission and reception) between the AP102 and the ML-STA103 will be described. FIG. 5 is a flowchart of the connection process between the AP102 and the ML-STA103 executed by the AP102 in this embodiment, which is the same as that in the first embodiment. FIG. 13 is a sequence chart of the connection process executed by the AP102 and the ML-STA103 in this embodiment. As described above, the AP102 and the ML-STA103 each have wireless LAN control units 201a, 201b, and 201c that can communicate in any of the 2.4 GHz band, 5 GHz band, and 6 GHz band.

[0066] In this embodiment, the frequency at which the AP 102 and the ML-STA 103 communicate a management frame for connection processing is 2.4 GHz, and this communication also controls connections in other frequency bands. Note that the use of 2.4 GHz is just an example, and the frequency at which the management frame is transmitted and received is not limited to this. The management frame is as described in the first embodiment.

[0067] The processes from F1301 to F1305 in Fig. 13 are the same as those in the first embodiment (corresponding to S501 to S503 in Fig. 5 and F601 to F605 in Fig. 6), and therefore the description will be omitted. In this embodiment, 5ch in the 2.4GHz band, 36ch in the 5GHz band, and 1ch in the 6GHz band are assumed to be links. Also, the AP 102 and the ML-STA 103 are assumed to have a function capable of communicating in a maximum 40MHz band in the 2.4GHz band, and in a maximum 160MHz band in the 5GHz and 6GHz bands.

[0068] When a connection is established between the AP 102 and the ML-STA 103, the multilink communication control unit 206 of the AP 102 optionally determines transmission and reception parameters (S504, F1306). The transmission and reception parameters are information (parameters) for determining how to distribute transmission and reception data to each connection when multiple connections are established, as explained in the first embodiment.

[0069] In addition, when performing multi-link communication, the communication mode control unit 207 of the AP 102 determines the communication mode for each link, that is, whether or not to perform transmission and reception simultaneously between each link. As in the first embodiment, the frequency interval between the two links to be used is F AP (=200MHz) and F ML-STA (=300 MHz), the communication mode control unit 207 determines not to transmit and receive simultaneously using the two links (not to use asynchronous mode). The wireless LAN control unit 201a of the AP 102 notifies the ML-STA 103 of the determination as a transmission / reception parameter (including the transmission / reception parameter).

[0070] Considering the maximum bandwidth available for communication, the frequency intervals between the links used for multi-link communication in this embodiment are as follows. · Frequency interval between 5ch and 36ch: 2708 MHz · Frequency interval between 36ch and 1ch in the 6 GHz band: 605 MHz · Frequency interval between 5ch and 1ch in the 6 GHz band: 3473 MHz Comparing these interval values with F AP (=200 MHz) and F ML-STA (=300 MHz), it can be seen that all the frequency intervals are larger than F AP and F ML-STA Therefore, the communication mode control unit 207 of AP102 determines that it is possible to perform transmission and reception simultaneously between each link (that is, either the synchronous mode or the asynchronous mode is acceptable). The wireless LAN control unit 201a of AP102 notifies ML-STA103 of this determination as a transmission / reception parameter (including it in the transmission / reception parameters).

[0071] Using the said transmission / reception parameters, AP102 and ML-STA103 start transmitting and receiving data using multi-link communication (S505, F1307~1309, F1311~F1313, F1321~F1322). In the example of FIG. 13, the wireless LAN control units 201a of AP102 and ML-STA103 perform multi-link communication using the asynchronous mode at 5ch (2.4 GHz band). Also, the wireless LAN control units 201b of AP102 and ML-STA103 perform multi-link communication using the asynchronous mode at 36ch (5 GHz band). Also, the wireless LAN control units 201c of AP102 and ML-STA103 perform multi-link communication using the asynchronous mode at 1ch (6 GHz band).

[0072] <Connection process between AP102 and NonML-STA104> Next, a connection process between the AP 102 and the NonML-STA 104 after the AP 102 establishes multi-link communication with the ML-STA 103 will be described with reference to Figures 14 and 15. Figure 14 shows a flowchart of the connection process with the NonML-STA 104 executed by the AP 102 in this embodiment, and Figure 15 shows a sequence chart of the connection process executed by the AP 102 and the NonML-STA 104 in this embodiment. As described above, the NonML-STA 104 has a wireless LAN control unit 211 capable of communication in any of the 2.4 GHz band, the 5 GHz band, and the 6 GHz band.

[0073] In Fig. 15, the AP 102 and the ML-STA 103 are assumed to be continuing data transmission and reception (F1501, F1502, F1511, F1512, F1531, F1532) following the data transmission and reception (S505, F1307-1309, F1311-F1313, F1321-F1322) shown in Fig. 5 and Fig. 13. At this time, the frequency band determination unit 205 of the AP 102 periodically determines which frequency band is to be made available (S1401). The AP 102 may make this determination depending on the degree of congestion in the surrounding wireless environment, but is not limited to this. In this embodiment, it is assumed that the 2.4 GHz band, the 5 GHz band, and the 6 GHz band are available.

[0074] In S1402, the AP 102 periodically transmits a Beacon using one of the available frequency bands (F1521). Here, it is assumed that the wireless LAN control unit 201b transmits a management frame including a Beacon frame to the NonML-STA 104 using the 5 GHz band. The wireless LAN control unit 201b assigns frequency band information of the AP 102 to the Beacon frame. The frequency band information is as described above, and may also include information indicating that the AP 102 supports multi-link communication.

[0075] The wireless LAN control unit 211 of the NonML-STA 104 that has received the Beacon frame transmits a Probe Request frame in one of its available frequency bands (5 GHz in this example) (F1522) and starts a scan operation. The wireless LAN control unit 211 of the NonML-STA 104 may add frequency band information of the NonML-STA 104 to the Probe Request frame. The frequency band information may include information on frequency bands available to the NonML-STA 104 and information indicating that the NonML-STA 104 does not support multi-link communication. Alternatively, the frequency band information may be configured not to include information indicating that the NonML-STA 104 supports multi-link communication. The NonML-STA 104 may notify the AP 102 of its own frequency information by including it in an Authentication Request, Association Request, or Reassociation Request frame.

[0076] The frame analysis unit 203 of the AP 102 analyzes the available frequency band information of the NonML-STA 104 that is attached to the Probe Request frame from the NonML-STA 104. The frame analysis unit 203 detects that the NonML-STA 104 does not support multilink communication because the frame contains information indicating that the NonML-STA 104 does not support multilink communication (or does not contain information indicating that the NonML-STA 104 supports multilink communication).

[0077] In this example, the frequency interval between each link is F AP and F ML-STASince the frequency band of the link is larger than either of the frequency bands, the communication mode control unit 207 of the AP102 determines that the condition for changing the communication mode is not satisfied. Therefore, the multilink communication control unit 206 does not change the frequency band of the link as in the first embodiment. The wireless LAN control unit 201b of the AP102 transmits a Probe Response frame including information on available frequency bands as a response to the Probe Request frame (F1522) from the NonML-STA 104 (F1523). The frame analysis unit 213 of the NonML-STA 104 detects the frequency supported by the AP102 and the channel operating at that frequency from the information on available frequency bands included in the Probe Response frame from the AP102.

[0078] Thereafter, the AP 102 and the NonML-STA 104 establish a connection by communication via the wireless LAN control unit 201b and the wireless LAN control unit 211 (S1403, F1524, F1525). When a secure connection using encryption is to be established between the AP 102 and the NonML-STA 104, communication processing such as WPA, WPA2, and WPA3 may be performed thereafter. In this embodiment, a connection without encryption will be described, but is not limited to this.

[0079] After this, the AP 102 and the ML-STA 103 continue to perform multi-link communication (in asynchronous mode) in which simultaneous transmission and reception can be performed (F1503 to F1505, F1513 to F1514, F1533 to F1537). Also, the AP 102 and the NonML-STA 104 perform data transmission and reception using single-link communication in one frequency band (F1526).

[0080] <Changing the frequency band used after disconnecting a STA that does not support multi-link> The process of restoring the frequency band used by the AP102 for multi-link communication with the ML-STA 103 after the NonML-STA 104 has disconnected from the AP102 is the same as that in the first embodiment (see the explanations of Figs. 11 and 12). That is, when the NonML-STA 104 has disconnected from the AP102, the communication mode control unit 207 of the AP102 determines that the condition for changing the communication mode is satisfied according to the communication situation. Thereafter, the AP102 transmits a channel switch announcement to the ML-STA 103 (F1202) as explained with reference to Fig. 12. As a result, the AP102 notifies the ML-STA of the change in the frequency band of the link and the frequency band after the change. Thereafter, the multi-link communication control unit 206 of the AP102 and the ML-STA 103 changes the link (F1233).

[0081] In this manner, in this embodiment, when a multi-link-compatible AP and a multi-link-compatible STA are performing multi-link communication in a mode in which they can simultaneously transmit and receive, even if a multi-link-compatible STA connects to the AP, the AP can be appropriately connected. This allows the AP and the multi-link-compatible STA to continue communication without reducing communication throughput.

[0082] [Third embodiment] This embodiment is an embodiment of a process of changing a mode (asynchronous mode) in which simultaneous transmission and reception can be performed when an AP and an ML-STA are performing multi-link communication in synchronous mode and are used in an application in which data is transmitted and received bidirectionally in real time. The configuration of the wireless communication system, the AP 102, the ML-STA 103, and the NonML-STA 104 are the same as those in the first embodiment, so descriptions of these are omitted. In this embodiment, the communication mode of multi-link communication is changed to asynchronous mode based on the access category defined in IEEE802.11e. The access category (AC) indicates the frame (packet) transmission priority.

[0083] <Change in frequency band used based on type of transmitted data> A process of changing to the asynchronous mode according to the type of transmission data after the AP 102 and the ML-STA 103 establish multi-link communication will be described with reference to Fig. 16. Fig. 16 is a sequence chart of a process of changing the frequency band in use again based on the type of transmission data in this embodiment. In this embodiment, the type of transmission data is classified according to the access category defined in IEEE802.11e. In the multi-link communication control unit 206 of the AP 102, AC_VO (access category for voice data) is set in advance as the access category that is a condition for changing to the asynchronous mode. AC_VO is the access category with the highest transmission priority.

[0084] 16, the AP 102 and the ML-STA 103 are in a state of communicating in synchronous mode with 2.4 GHz 5ch, 5 GHz 36ch, and 5 GHz 100ch as links (F1601, F1602, F1611, F1622, F1621, F1622) according to the procedure shown in the first embodiment, for example. Here, it is assumed that an application that transmits and receives data bidirectionally in real time is being executed in the AP 102 and the ML-STA 103.

[0085] Assume that data addressed to the ML-STA 103, which is generated by an application that transmits and receives data bidirectionally in real time, enters a transmission queue in the communication unit 307 of the AP 102 as a frame of the AC_VO category in F1603. The multilink communication control unit 206 of the AP 102 detects that the transmission data addressed to the ML-STA 103 is a specific type of data that satisfies the conditions for changing the communication mode, based on the access category of the data (transmission data) addressed to the ML-STA 103. In this case, the communication mode control unit 207 determines that the conditions for changing the communication mode are satisfied. The multilink communication control unit 206 decides to change the link from the synchronous mode to a frequency band that allows simultaneous transmission and reception (asynchronous mode), and performs the change process. Specifically, the multilink communication control unit 206 checks whether the frequency intervals between the respective links are within the range of F AP and FML-STA In this example, the distance between the two links, 36ch and 100ch, is 160MHz. AP (=300MHz) and F ML-STA (=200 MHz). Therefore, the AP 102 changes to 100ch. Specifically, as described in the first embodiment with reference to FIG. 10, the AP 102 changes to 1ch (center frequency 5945 MHz) in the 6 GHz band, which can secure a 160 MHz bandwidth. As a result, the frequency interval becomes 605 MHz, and F AP and F ML-STA Therefore, the AP102 and the ML-STA103 can simultaneously transmit and receive between the links of 36ch in the 5GHz band and 1ch in the 6GHz band without interference within the device.

[0086] The wireless LAN control unit 201a of the AP 102 transmits a channel switch announcement to the ML-STA 103, notifying the change in the frequency band of the link and the frequency band after the change (F1604). After that, the multilink communication control units 206 of the AP 102 and the ML-STA 103 perform control to change the link (F1623). Furthermore, the multilink communication control unit 206 of the AP 102 determines that in multilink communication with the ML-STA 103, transmission and reception may be performed simultaneously on either link. In other words, the multilink communication control unit 206 of the AP 102 determines that communication may be performed in either the synchronous mode or the asynchronous mode. The wireless LAN control unit 201a of the AP 102 notifies the ML-STA 103 of the determination. Thereafter, the AP 102 transmits and receives data to and from the ML-STA 103 through multi-link communication (F1605 to F1607, F1613 to F1615, F1624 to F1627).

[0087] In this embodiment, the synchronous mode is changed to the asynchronous mode on the condition that a frame of the AC_VO category is placed in the transmission queue, but other access categories may be used. Also, instead of the access category, a parameter indicating the transmission priority of other data may be used as the condition.

[0088] <Processing for changing frequency bands in use based on the type of data being transmitted> Next, the process of restoring the frequency band used by the AP 102 for multilink communication with the ML-STA 103 after frames in the AC_VO category are no longer in the transmission queue of the AP 102 will be described with reference to Fig. 17. Even after frames in the AC_VO category are no longer in the transmission queue due to reasons such as the end of use of an application that transmits and receives data in real time in both directions, communication with the ML-STA 103 can continue without changing the frequency band of the link. On the other hand, the frequency band can be restored and the mode can be changed to synchronous mode due to reasons such as the communication situation of the frequency band being congested.

[0089] Fig. 17 is a sequence chart of the process of re-changing the frequency band in use based on the type of transmission data (access category) in this embodiment. First, the multilink communication control unit 206 of the AP 102 judges that a state has been reached where frames of the AC_VO category are not queued for transmission (F1701). The multilink communication control unit 106 makes the judgment on the condition that frames of the AC_VO category are not queued for a certain period of time (e.g., 300 seconds) that is set in advance. In response to this, the communication mode control unit 207 of the AP 102 judges that the condition for changing the communication mode is met according to the communication situation. The subsequent processes (F1702 to F1725) are the same as those in Fig. 12 described in the first embodiment, and therefore will not be described again.

[0090] In this way, in this embodiment, when an AP and a STA that support multi-link communication are performing multi-link communication in synchronous mode and start transmitting and receiving data in real time in both directions, the frequency band used is changed to a frequency band that allows multi-link communication in asynchronous mode, and simultaneous transmission and reception is possible. This makes it possible to prevent the use of an application that transmits and receives data in both directions in real time from being affected, even when performing multi-link communication in synchronous mode.

[0091] [Fourth embodiment] This embodiment is an embodiment related to processing when used in an application in which data is transmitted and received bidirectionally in real time in a state where multi-link communication is performed using a frequency band in which the AP and ML-STA can simultaneously transmit and receive. The configuration of the wireless communication system, the AP 102, the ML-STA 103, and the NonML-STA 104 are the same as those in the first embodiment, so descriptions thereof will be omitted. As in the third embodiment, in this embodiment, an example will be described in which the access category defined in IEEE802.11e is used as the type of transmission data.

[0092] <Processing based on the type of transmitted data> Using FIG. 18, a process performed according to the type of transmission data after the AP 102 and the ML-STA 103 establish multi-link communication will be described. FIG. 18 is a sequence chart diagram of the process based on the type of transmission data in this embodiment. The AP 102 and the ML-STA 103 are in a state of communication in synchronous mode using 2.4 GHz 5ch, 5 GHz 36ch, and 6 GHz 1ch as links (F1801, F1802, F1811, F1812, F1821, F1822). Here, it is assumed that an application that transmits and receives data bidirectionally in real time is executed in the AP 102 and the ML-STA 103. Also, it is assumed that AC_VO (access category for voice data) is set in advance in the multi-link communication control unit 206 of the AP 102 as the access category that is a condition for changing to the asynchronous mode. AC_VO is the access category with the highest transmission priority.

[0093] Assume that data addressed to the ML-STA 103, which is generated by an application that transmits and receives data bidirectionally in real time, is entered into a transmission queue in the communication unit 307 of the AP 102 as a frame of the AC_VO category in F1803. The multilink communication control unit 206 of the AP 102 detects that the transmission data is a specific type of data that satisfies the conditions for changing the communication mode based on the access category of the data (transmission data) addressed to the ML-STA 103. In this case, the communication mode control unit 207 determines that the conditions for changing the communication mode are satisfied.

[0094] The multi-link communication control unit 206 of the AP 102 determines the frequency bands to be used in the links and the frequency intervals between the links as F AP , F ML-STA The frequency band is determined so as to be larger than either of the frequency bands. In this example, since multilink communication is already performed using a frequency band that allows simultaneous transmission and reception, the multilink communication control unit 206 does not change the frequency band of the link. The AP 102 continues to transmit and receive data with the ML-STA 103 through multilink communication (F1804 to F1806, F1813 to F1815, F1823 to F1826) using a mode that allows simultaneous transmission and reception.

[0095] <Change in frequency band> Even after the frame of the AC_VO category is no longer in the transmission queue, the AP 102 can continue to communicate with the ML-STA 103 without changing the frequency band of the link. On the other hand, the AP 102 can also change the frequency band to the synchronous mode due to reasons such as congestion in the communication situation of the frequency band being used. The process of returning to the synchronous mode is the same as that described in the third embodiment with reference to FIG. 17, and therefore will not be described here.

[0096] In this way, in this embodiment, when an AP and a multi-link-compatible STA are performing multi-link communication using a frequency band in which they can simultaneously transmit and receive, appropriate processing can be performed when starting to use an application that transmits and receives data in both directions in real time.

[0097] [Other embodiments] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0098] The invention is not limited to the above-described embodiments, and various modifications and variations are possible 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]

[0099] 101 network, 102 AP (access point), 103; 104 STA (station / terminal device)

Claims

1. A communication device capable of multi-link communication conforming to the IEEE 802.11 series of standards, A communication means for performing communication in either a first mode in which transmission and reception are performed independently on each of a plurality of frequency channels, or a second mode in which transmission or reception is performed simultaneously on each of a plurality of frequency channels; A communication mode change means for carrying out a process of changing the communication mode; a determination means for determining a frequency channel to be used for communication in the communication mode after the communication mode change means has been performed, A communication device characterized in that, when a connection is made by a second other communication device while the communication means is communicating with a first other communication device using each frequency channel of a plurality of frequency channels in the second mode, the determination means determines a frequency channel such that a frequency interval between two adjacent frequency channels among the plurality of frequency channels is equal to or greater than a predetermined interval, and the communication means communicates with the first other communication device in the first mode using the determined frequency channel.

2. The communication device according to claim 1, characterized in that, when a frequency interval between two adjacent frequency channels among the plurality of frequency channels is smaller than a predetermined interval, the communication means communicates with the first other communication device in the second mode on the two frequency channels, and when a frequency interval between two adjacent frequency channels is equal to or greater than the predetermined interval, the communication means communicates with the first other communication device in the first mode or the second mode on the two frequency channels.

3. 2. The communication device according to claim 1, wherein the predetermined interval is a frequency interval value required for both the communication device and the first other communication device to simultaneously transmit and receive on each of a plurality of frequency channels.

4. In a state in which the communication device is connected to the first other communication device and the second other communication device, 2. The communication device according to claim 1, characterized in that, when the second other communication device disconnects from the communication device while the communication means is communicating with the first other communication device in the first mode using multiple frequency channels, the determination means determines multiple frequency channels such that a frequency interval between the first frequency channel and the one or more adjacent frequency channels is smaller than the predetermined interval.

5. A communication device capable of multi-link communication conforming to the IEEE 802.11 series of standards, A communication means for performing communication in either a first mode in which transmission and reception are performed independently on each of a plurality of frequency channels, or a second mode in which transmission or reception is performed simultaneously on each of a plurality of frequency channels; A communication mode change means for carrying out a process of changing the communication mode; a determination means for determining a frequency channel to be used for communication in the communication mode after the communication mode change by the communication mode change means; A determination means for determining a type of data generated for transmission to another communication device, A communication device characterized in that, when the determination means determines that the data is a specific type of data while the communication means is communicating with the other communication device in the second mode, the determination means determines a frequency channel so that the frequency interval between two adjacent frequency channels is equal to or greater than a predetermined interval.

6. 6. The communication device according to claim 5, characterized in that, when the determination means determines that the data is not the specific type of data while the communication means is communicating with the other communication device in the first mode using multiple frequency channels, the decision means determines multiple frequency channels such that a frequency interval between the first frequency channel and the one or more adjacent frequency channels is smaller than the predetermined interval.

7. 7. The communication device according to claim 5, wherein the determining means determines that the data is the specific type of data based on an access category defined in IEEE802.11e.

8. A method for controlling a communication device capable of multi-link communication conforming to the IEEE 802.11 series of standards, comprising: a communication step of performing communication in either a first mode in which transmission and reception are performed independently on each of the plurality of frequency channels, or a second mode in which transmission or reception is performed simultaneously on each of the plurality of frequency channels; a communication mode changing step of carrying out a process of changing the communication mode; a determination step of determining a frequency channel to be used for communication in the communication mode changed in the communication mode change step, A control method characterized in that, when a connection is made by a second other communication device while communicating with a first other communication device using each frequency channel of a plurality of frequency channels in the second mode in the communication process, in the determination process, a frequency channel is determined so that the frequency interval between two adjacent frequency channels among the plurality of frequency channels is equal to or greater than a predetermined interval, and after this determination, the communication process communicates with the first other communication device in the first mode using the determined frequency channel.

9. A program for causing a computer to function as the communication device according to any one of claims 1 to 7.

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