Communication device, control method, and program

Abstract

To enable efficient wireless communication in a wireless communication system capable of configuring multi-links.SOLUTION: A communication device that establishes a plurality of links with another device and performs wireless communication conforming to the IEEE802.11 standard series, updates an encryption key that is set individually for each of the plurality of links by executing a predetermined process including sending a predetermined message to the other device. The communication device causes information about two or more of the plurality of links to be included in a predetermined message, and sends the information to the other device in the predetermined process.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a communication control technique using multiple wireless links. [Background technology]

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is known as a communication standard for wireless local area networks (WLANs). The IEEE 802.11ax standard, one of the standards in the IEEE 802.11 series, uses orthogonal frequency division multiple access (OFDMA) to achieve high peak throughput as well as improved communication speeds under congested conditions (see Patent Document 1).

[0003] Currently, a task group has been formed to develop a new standard, the IEEE802.11be, to further improve throughput. This task group is studying multi-link communication, in which one access point (AP) establishes multiple wireless links with one station (STA) via different frequency channels, and communicates in parallel.

[0004] In wireless LANs, encrypted data is generally transmitted using data frames. For this encryption, a Pairwise Transient Key (PTK) is used for one-to-one data transmission, and a Group Transient Key (GTK) is used for multicast data transmission. In multi-link communication, these keys are managed differently. That is, a PTK is generated for each device regardless of the number of links and is managed only between the two devices communicating, while a GTK is generated for each of the multiple links in multi-link communication. The PTK and GTK are generated when a STA connects to an AP. Furthermore, the GTK is updated every time a specified period set by the AP has elapsed after the connection between the AP and STA is established. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-050133 Summary of the Invention [Problem to be solved by the invention]

[0006] When updating the GTK, a specific frame is exchanged between the AP and the STA. However, as mentioned above, the GTK is generated for each link and updated at specific intervals. Therefore, as the number of links in multi-link communication increases, the communication overhead also increases.

[0007] The present invention provides an efficient communication control technique in a wireless communication system capable of configuring multiple links. [Means for solving the problem]

[0008] A communication device according to one embodiment of the present invention is a communication device that establishes multiple links with another device and performs wireless communication in accordance with the IEEE 802.11 standard series, and has an update means that updates an encryption key that is individually set for each of the multiple links by performing a predetermined process that includes sending a predetermined message to the other device, and is characterized in that, in the predetermined process, the update means includes information about two or more links of the multiple links in the predetermined message and sends it to the other device. [Effects of the Invention]

[0009] According to the present invention, efficient wireless communication can be achieved in a wireless communication system capable of configuring a multi-link. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 illustrates an example of a system configuration. [Figure 2] FIG. 2 illustrates an example of the hardware configuration of an AP. [Figure 3] FIG. 2 is a diagram illustrating an example of a functional configuration of an AP. [Figure 4] FIG. 10 is a diagram illustrating a first example of a GTK update process executed between an AP and a STA. [Figure 5] FIG. 10 is a diagram illustrating a second example of a GTK update process executed between an AP and a STA. [Figure 6] FIG. 10 is a diagram illustrating a third example of a GTK update process executed between an AP and a STA. [Figure 7] FIG. 10 is a diagram illustrating a first example of a process for setting a GTK update interval by an AP. [Figure 8] FIG. 10 is a diagram illustrating a second example of a process for setting a GTK update interval by an AP. [Figure 9] FIG. 10 is a diagram illustrating an example of a screen for setting the GTK update interval. [Figure 10] FIG. 10 is a diagram illustrating an example of processing performed by an AP when communicating with a STA. [Figure 11] This is a table showing the fields and their contents included in MLO GTK KDE. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] (System Configuration) 1 shows an example of the configuration of a wireless communication system according to this embodiment. This wireless communication system includes a wireless LAN (Local Area Network) access point (AP 102) and a station (STA 103) as wireless communication devices. The STA 103 joins a network 101 formed by the AP 102, thereby performing wireless communication between the AP 102 and the STA 103. In one example, both the AP 102 and the STA 103 are capable of performing wireless communication compliant with the IEEE (Institute of Electrical and Electronics Engineers) 802.11be (EHT) standard. Note that EHT stands for Extremely High Throughput, but it may also be interpreted as an abbreviation for Extreme High Throughput.

[0013] As an example, the STA 103 is configured to perform multilink communication, which establishes multiple wireless links with the AP 102 and performs communication, and is capable of transmitting and receiving frames via each of the multiple wireless links. FIG. 1 illustrates an example in which two links, a first link 104 and a second link 105, are used. Each link may use a channel (frequency channel) in the 2.4 GHz, 5 GHz, or 6 GHz frequency band. Note that the frequency bands used are not limited to these, and another frequency band, such as the 60 GHz band, may also be used. In one example, the AP 102 and the STA 103 may establish and communicate in parallel the first link 104 using a channel in the first frequency band (e.g., the 2.4 GHz band) and the second link 105 using a channel in the second frequency band (e.g., the 5 GHz band). Note that the frequency channel to be used may be selected according to multilink communication capability information of the STA and the AP. For example, a combination of channels in the 2.4 GHz band and the 5 GHz band may be used, or a combination of multiple channels selected from the 6 GHz band may be used. Multilink communication may also be performed using multiple channels within a single frequency band. That is, any combination of frequency channels may be used for the multiple links in multilink communication, as long as the multiple links use different frequency channels. However, the frequency channels used for the multiple links established between the AP 102 and the STA 103 are selected so that the channel spacing between the frequency channels is at least greater than 20 MHz. While maintaining a first link 104 on a first frequency channel, the AP 102 also maintains a second link 105 on a second frequency channel.

[0014] While FIG. 1 illustrates an example in which two links are established between the AP 102 and the STA 103, three or more links may be established. The three or more links may each use a frequency channel in a different frequency band, or two or more of the three or more links may use different frequency channels within the same frequency band. In this way, the AP 102 can improve the throughput of communication with the STA 103 by establishing links with the STA 103 via multiple frequency channels. Furthermore, by establishing multiple connections with the STA 103 via different frequency channels, the AP 102 can communicate with the STA 103 via other frequency channels even if one frequency channel is congested. Therefore, the AP 102 can prevent a decrease in the overall throughput of communication with the STA 103 even if some frequency channels are congested and cannot achieve sufficient throughput.

[0015] When performing multi-link communication, the AP 102 establishes multiple wireless networks corresponding to the multiple links. In this case, the AP 102 has multiple APs internally, each of which operates to establish a wireless network. The multiple APs internal to the AP 102 may be realized by separate physical APs (such as communication circuits with AP functionality), or may be realized as multiple virtual APs by a single physical AP. When multiple links are established using different frequency channels belonging to a common frequency band, a common wireless network may be established for the multiple links.

[0016] When performing multi-link communication, the AP 102 and the STA 103 may divide a single piece of data and transmit it to a partner device via multiple links. The AP 102 and the STA 103 may also transmit the same data via each of multiple links, allowing communications via some links to function as backup communications for communications via other links. For example, the AP 102 may transmit the same data to the STA 103 via a first link using a first frequency channel and a second link using a second frequency channel. In this case, even if an error occurs in communication via the first link, the same data is transmitted via the second link, allowing the STA 103 to receive the data transmitted from the AP 102 via the second link. The AP 102 and the STA 103 may also use different links depending on the type of frame or data to be communicated. For example, when transmitting data related to a captured image, the AP 102 may transmit meta-information such as the date, parameters at the time of capture (aperture value and shutter speed), and location information via the first link, and pixel information via the second link. The AP 102 may also transmit management frames conforming to the IEEE 802.11 series of standards via the first link, and may transmit data frames containing data via the second link.

[0017] Management frames include, for example, Beacon frames, Probe Request frames / Response frames, and Association Request frames / Response frames. In addition to these frames, Disassociation frames, Authentication frames, De-Authentication frames, and Action frames are also called management frames. Beacon frames are frames that report network information. Probe Request frames are frames that request network information, and Probe Response frames are corresponding responses that provide network information. Association Request frames are frames that request a connection, and Association Response frames are corresponding responses that indicate permission for connection or an error. Disassociation frames are frames that disconnect a connection. Authentication frames are frames that authenticate the other device, and De-Authentication frames are frames that interrupt authentication of the other device and disconnect the connection. Action frames are frames used for additional functions other than those mentioned above. In addition to the Beacon frame, the AP 102 may transmit at least one of a FILS Discovery frame and an Unsolicited Probe Response frame to notify network information. FILS is an acronym for Fast Initial Link Setup.

[0018] Although the AP 102 and the STA 103 are described as being compatible with the IEEE 802.11be standard, they may also be compatible with at least one legacy standard that predates the IEEE 802.11be standard. Legacy standards include, for example, the IEEE 802.11a / b / g / n / ac / ax standards. In this embodiment, the IEEE 802.11 standard series refers to at least one of the IEEE 802.11a / b / g / n / ac / ax / be standards. In addition to the IEEE 802.11 standard series, they may also be compatible with other communication standards such as Bluetooth (registered trademark), NFC, UWB, Zigbee, and MBOA. UWB is an acronym for Ultra Wide Band, and MBOA is an acronym for Multi-Band OFDM Alliance. OFDM is an acronym for Orthogonal Frequency Division Multiplexing. NFC is an acronym for Near Field Communication. UWB includes wireless USB (Universal Serial Bus), wireless 1394, Winet, etc. It may also be compatible with wired communication standards such as wired LAN.

[0019] The AP 102 may be, for example, a wireless LAN router or a PC (personal computer), but is not limited to these, and may be any communication device capable of performing multilink communication with other communication devices. The STA 103 may be, for example, a camera, a tablet, a smartphone, a PC, a mobile phone, a video camera, but is not limited to these, and may be any communication device capable of performing multilink communication with other communication devices, similar to the AP 102. Although FIG. 1 shows only one AP and one STA, the number of APs and STAs is not limited to this.

[0020] In this embodiment, the AP 102 is an access point and the STA 103 is a station, but this is not limiting, and both the AP 102 and the STA 103 may be stations. In this case, the AP 102 is a station, but operates as a device that has a role of constructing a wireless network for establishing a link with the STA 103.

[0021] (Device configuration) 2 is a diagram showing an example of the hardware configuration of the AP 102 according to this embodiment. The AP 102 includes, for example, a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207. The STA 103 may also have a similar configuration.

[0022] The storage unit 201 is configured to include one or more memories such as ROM and RAM, and stores various information such as computer programs for performing various operations described below and communication parameters for wireless communication. ROM is an acronym for Read Only Memory, and RAM is an acronym for Random Access Memory. The storage unit 201 may include storage media such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, a DVD, etc., in addition to or instead of memories such as ROM and RAM. The storage unit 201 may also include multiple memories.

[0023] The control unit 202 is configured with one or more processors, such as a CPU or an MPU, and controls the entire AP 102 by executing a computer program stored in the storage unit 201, for example. Note that CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit 202 may be configured to perform processes for generating data and signals to be transmitted in communication with other communication devices (e.g., the STA 103) in addition to the overall control of the AP 102. Note that the control unit 202 may be configured to perform processes such as the overall control of the AP 102 in cooperation with a computer program stored in the storage unit 201 and an OS (Operating System). The control unit 202 may also include multiple processors, such as a multi-core processor, and may perform processes such as the overall control of the AP 102 using the multiple processors. The control unit 202 may also be configured with an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or the like.

[0024] Furthermore, the control unit 202 controls the functional unit 203 to execute predetermined processes such as capturing images, printing, and projection. The functional unit 203 is hardware that causes the AP 102 to execute predetermined processes. For example, if the AP 102 is a camera, the functional unit 203 is an imaging unit that performs imaging processing. For example, if the AP 102 is a printer, the functional unit 203 is a printing unit that performs printing processing. For example, if the AP 102 is a projector, the functional unit 203 is a projection unit that performs projection processing. The data processed by the functional unit 203 may be data stored in the storage unit 201, or may be data communicated with another communication device (e.g., STA 103) via the communication unit 206, which will be described later.

[0025] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes, for example, at least one of a display on a screen, an audio output from a speaker, and a vibration output. Note that both the input unit 204 and the output unit 205 may be implemented by a single module, such as a touch panel. Furthermore, the input unit 204 and the output unit 205 may each be built into the AP 102, or may be configured as an external device connected to a communication device.

[0026] The communication unit 206 controls wireless communications compliant with the IEEE 802.11 standard series and IP communications. In this embodiment, the communication unit 206 is configured to control wireless communications compliant with the IEEE 802.11be standard, in particular. The communication unit 206 may also control wireless communications compliant with other IEEE 802.11 standard series in addition to the IEEE 802.11be standard, or wired communications such as a wired LAN. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communications generated by the control unit 202, for example. The AP 102 may have multiple communication units 206. When the AP 102 has multiple communication units 206, one link may be established using one communication unit 206 when establishing multiple links in multi-link communication. The AP 102 may establish one link for each of some communication units 206 and multiple links for other communication units 206. The AP 102 may also establish multiple links using one communication unit 206. In this case, the communication unit 206 can perform communication via multiple links by switching the operating frequency channel in a time-division manner. If the AP 102 supports the NFC standard, Bluetooth standard, or the like in addition to the IEEE 802.11be standard, it may control wireless communication in accordance with these communication standards. If the AP 102 is capable of performing wireless communication in accordance with multiple communication standards, it may have separate communication units and antennas compatible with each communication standard. The AP 102 communicates data such as image data, document data, and video data with a communication partner device (e.g., the STA 103) via the communication unit 206. The antenna 207 may be provided separately from the communication unit 206, or may be configured as a single module together with the communication unit 206.

[0027] Antenna 207 is an antenna capable of communication in the sub-GHz band, 2.4 GHz band, 5 GHz band, and 6 GHz band. Note that AP 102 may have a multi-band antenna as antenna 207, or may have multiple antennas corresponding to each frequency band. If AP 102 has multiple antennas, it may have one communication unit 206 for the multiple antennas, or multiple communication units 206 corresponding to each of the multiple antennas. Note that antenna 207 may be a single antenna or an antenna array. That is, antenna 207 may have multiple antenna elements and be configured to be able to perform communication using, for example, MIMO (Multi-Input and Multi-Output).

[0028] 3 shows an example of the functional configuration of AP 102 of this embodiment. AP 102 is configured to include, as a rough functional configuration, a multi-link control unit 301, a GTK update interval input unit 302, an encryption key management unit 303, a GTK update interval control unit 304, a GTK update request frame generation unit 305, and a frame transmission / reception unit 306. Note that these functional units can be realized, for example, by the control unit 202 executing a program stored in the storage unit 201. However, this is merely an example, and at least some of these functions may be configured by dedicated hardware.

[0029] The multilink control unit 301 controls, for example, a communication initiation process for the AP 102 to establish one or more links for wireless communication with the STA 103, a process for adding or deleting links after communication has started, and a communication termination process for deleting all links. When connecting with the STA 103, the AP 102 may establish multiple link connections in advance, or may add another link while communicating with a previous link. Furthermore, the AP 102 may also delete one of the multiple links while communicating with the STA 103. Connection processes performed between the AP 102 and the STA 103 include, for example, authentication, association, and 4-Way Handshake (4WHS) processes. These processes are defined in the IEEE 802.11 standard series and will not be described in detail here. Upon completing the 4WHS process, the AP 102 and the STA 103 generate a PTK, which is an encryption key for unicast communication, and a GTK, which is an encryption key for broadcast and multicast communication. PTK is an acronym for Pairwise Transient Key, and GTK is an acronym for Group Transient Key. PTK is generated for each device (i.e., for each AP 102 and STA 103) regardless of the number of links, and is managed only between the two devices communicating. On the other hand, GTK is generated individually for each of the multiple links in multi-link communication.

[0030] The GTK update interval input unit 302 provides an interface for allowing a user to input a GTK update interval, for example, by outputting a predetermined web page. The GTK update interval input unit 302 then accepts user input specifying the GTK update interval via the interface. The AP 102 may be configured to use a GTK update interval preset in a program executed within the device, in which case the GTK update interval input unit 302 may be omitted. The encryption key management unit 303 manages the encryption keys acquired by the multi-link control unit 301. As described above, encryption keys include the PTK and the GTK, and the PTK is managed on a device-by-device basis, while the GTK is managed on a link-by-link basis. The GTK update interval control unit 304 then manages the GTK update timing for each link. The GTK update interval control unit 304 then notifies the GTK update request frame generation unit 305 that the GTK should be updated at a predetermined timing based on the update timing it manages. The predetermined timing may be the same as the update timing, or may be a predetermined time before the update timing, such as the time from when the update process starts to when the update process is completed. GTK update request frame generator 305 generates a GTK update request frame based on receiving notification of an update from GTK update interval controller 304. Frame transmitter / receiver 306 transmits wireless frames such as GTK update request frames and data frames, and receives wireless frames from the remote device.

[0031] The GTK update request frame generated by the GTK update request frame generator 305 includes one or more MLO GTK KDEs. MLO is an acronym for Multi-Link Operation, and KDE is an acronym for Key Data Encapsulation. The MLO GTK KDE includes information such as a Link ID, which is identification information for each link in multi-link communication, and a GTK, which is information about an encryption key (for example, after updating). In other words, the MLO GTK KDE here can be configured as an information element for one link, including identification information for that link and information about the (updated) encryption key to be used on that link. Figure 11 shows the fields included in the MLO GTK KDE defined in the IEEE 802.11be standard and their contents.

[0032] A GTK update request frame is transmitted each time a GTK update occurs on each link. Therefore, updating the GTK on each of multiple links results in the transmission of multiple GTK update request frames, which can waste radio resources. Therefore, the AP 102 according to this embodiment completes GTK updates on multiple links in a single update process. That is, the AP 102 may transmit, for example, a single GTK update request frame containing individual MLO GTK KDEs for each of two or more links. This reduces the number of times GTK update request frames are transmitted and prevents waste of radio resources. Furthermore, in order to include information about each of two or more links in a single GTK update request frame, the AP 102 may perform admission control to set the update periods of the two or more links so that the update timings of those links are consistent. This allows multiple links with a common GTK update timing to transmit a single GTK update request frame containing MLO GTK KDEs for those links without disrupting the update period. An example of such processing is described below.

[0033] (Processing flow within the system) FIG. 4 shows a first example of the flow of processing between the AP 102 and the STA 103. FIG. 4 illustrates an example of the flow of processing when the AP 102 sets the GTK update intervals for Link 1 and Link 2 to be equal. This processing corresponds to processing when a user inputs an equal GTK update interval via a setting screen displayed by the AP 102 (e.g., on an external display) or when the AP 102 is pre-configured to set the GTK update intervals for multiple links to be equal. The AP 102 and the STA 103 may process communication via a first frequency channel (e.g., channel 1 in the 2.4 GHz band) for Link 1 and a second frequency channel (e.g., channel 36 in the 5 GHz band) for Link 2. Note that the channels used are merely examples, and other combinations of frequency channels may also be used. The processing in FIG. 4 is initiated, for example, by the STA 103 initiating processing for establishing a connection to the AP 102.

[0034] First, the AP 102 and the STA 103 transmit and receive messages for authentication on a first frequency channel (S401). The STA 103 transmits an Authentication Request frame for authentication to the AP 102. In response to this, the AP 102 transmits an Authentication Response frame to the STA 103. Note that the SAE (Simultaneous Authentication Equal) method may be used as the authentication method. In this case, the Authentication Request frame and the Authentication Response frame are transmitted and received multiple times.

[0035] Thereafter, the AP 102 and the STA 103 transmit and receive messages for establishing a connection (S402). To establish a connection, the STA 103 transmits an Association Request frame to the AP 102. In response to this, the AP 102 transmits an Association Response frame to the STA 103 (S402). Here, the STA 103 can indicate to the AP 102 that it is requesting a connection over multiple links by including a Multi-link element in the Association Request frame. The Multi-link element includes information such as identification information (Link ID) for identifying the link for which the connection is requested. The AP 102 can also transmit an Association Response frame to the STA 103 that includes a Multi-link element including information about the link for which the connection has been permitted.

[0036] Then, AP102 and STA103 execute 4WHS processing to generate an encryption key to be used for communication (S403). The flow of 4WHS processing is the same as in the past, with four predetermined messages (Message 1 to Message 4) being sent and received. Here, AP102 includes an MLO GTK KDE, which has the Link ID and GTK for each of the multiple links, in Message 3 (4WHS Msg3) and sends it to STA103. FIG. 4 shows an example in which MLO GTK KDE1 for Link 1 and MLO GTK KDE2 for Link 2 are included in Message 3 and sent. Through this processing, AP102 and STA103 set the GTKs for Link 1 and Link 2 in their respective wireless chips. After setting the GTKs, AP102 resets and starts the timers for updating the GTKs for each link and begins measuring time.

[0037] When the time measured by the timer reaches the update interval, AP 102 determines that the timing for updating the GTK has arrived and starts GKHS (Group Key Handshake) processing with STA 103 to update the GTK. In GKHS processing, predetermined messages (Message 1 and Message 2) are sent and received between devices (AP 102 and STA 103) that have established a link corresponding to the GTK to be updated. For example, AP 102 sends Message 1 (GKHS Msg1) to STA 103, which contains an MLO GTK KDE that includes the Link ID and GTK of the link whose GTK is to be updated (S404). Then, STA 103 sends Message 2 (GKHS Msg2) to AP 102 based on the successful reception of Message 1 (S405). This causes the GTK to be shared between AP 102 and STA 103, completing the GTK update. In this embodiment, if the GTK update timings for multiple links coincide, Message 1 is sent containing the MLO GTK KDEs for those multiple links. In the example of FIG. 4, as described above, the GTK update intervals for Link 1 and Link 2 are set equal, so the GTK update timings for Link 1 and Link 2 coincide. Therefore, AP 102 sends Message 1 containing MLO GTK KDE1 for Link 1 and MLO GTK KDE2 for Link 2. That is, AP 102 transmits one Message 1 containing two MLO GTK KDEs for both Link 1 and Link 2. Then, STA 103 responds to Message 1 by sending Message 2, thereby updating both GTKs for the two links. That is, two Messages 1 are not sent for the two GTK updates, and the two GTK updates can be completed with one Message 1. Thereafter, AP 102 and STA 103 continue to update the GTKs for Link 1 and Link 2 at the same timing. In this way, the number of messages for updating the GTK can be reduced, and waste of radio resources can be suppressed.

[0038] In this embodiment, an example is shown in which one message 1 containing MLO GTK KDEs for multiple links is transmitted via link 1, but it may also be transmitted via link 2. That is, for example, GKHS processing may be performed on link 2, and message 1 containing MLO GTK KDE1 for link 1 and MLO GTK KDE2 for link 2 may be transmitted via link 2. Also, although the case where AP 102 transmits message 1 has been described, STA 103 may also transmit this message. The same applies to other processing examples.

[0039] In the example of Figure 4, the processing flow was explained when the GTK update periods of the two links (Link 1 and Link 2) are the same. In other cases, the GTK can be updated while reducing the number of times Message 1 is sent, as described above. For example, this can be the case when the length of the GTK update period of one link is a multiple or divisor of the length of the GTK update period of the other link. Figure 5 shows an example of the processing flow when the length of the GTK update interval of Link 2 is twice the length of the GTK update interval of Link 1. Note that the GTK setting process after the end of 4WHS and the process up to resetting and starting the timer are the same as those in Figure 4, so their explanations are omitted here.

[0040] Here, because the length of the GTK update interval for link 2 is twice the length of the GTK time interval for link 1, the GTK update timing arrives first only for link 1. Therefore, at this update timing, AP 102 sends message 1 including MLO GTK KDE1 for link 1 to STA 103 and executes GKHS processing (S501). Note that at this point, it is not time to update the GTK for link 2, so AP 102 sends message 1 without MLO GTK KDE2 for link 2 to STA 103. Upon successfully receiving message 1, STA 103 sends message 2 to AP 102. As a result, AP 102 and STA 103 update the GTK for link 1. AP 102 then resets the GTK update timer for link 1.

[0041] In the example of FIG. 5, when the next time comes for updating the GTK for link 1, it will also be time for link 2 to update its GTK at that time. Therefore, at this time, AP 102 generates message 1 including MLO GTK KDE1 for link 1 and MLO GTK KDE2 for link 2, as in S404 of FIG. 4, and sends it to STA 103 (S503). If STA 103 successfully receives this message, it responds by sending message 2 to AP 102 (S504). This allows AP 102 and STA 103 to simultaneously update the GTK for link 1 and the GTK for link 2. AP 102 then resets the GTK update timers for link 1 and link 2. Thereafter, the processes of S501 to S504 are repeatedly executed.

[0042] In this way, by setting the length of the GTK update period of some of the multiple links to a multiple or divisor of the length of the GTK update period of the other links, the frequency of messages sent when the GTK is updated can be reduced. In this embodiment, "multiple" refers to a positive integer multiple of a reference value, and does not include zero or negative integer multiples. However, multiples may also include a single multiple of the reference value (i.e., the same multiple). This generalizes the cases of FIGS. 4 and 5, and can be said to enable the processing of this embodiment to be performed when the length of the GTK update period of some links is a multiple or divisor of the length of the GTK update period of the other links.

[0043] 6 shows an example of the processing flow when link 3 is added while link 1 and link 2 have been established and are being used for communication between AP 102 and STA 103. Note that in the example of FIG. 6, the GTK update intervals of all links are assumed to be equal. However, this is just one example; for example, the GTK update interval of link 2 may be twice that of link 1, and the GTK update interval of link 3 may be three times that of link 1. In other words, any relationship between the update periods may be used as long as the length of the GTK update periods of some of the multiple links is a multiple or divisor of the length of the GTK update periods of the other links.

[0044] When the time comes to update the GTKs for Link 1 and Link 2 while Link 1 and Link 2 are established, AP 102 sends Message 1 including the MLO GTK KDEs for Link 1 and Link 2 to STA 103 (S601), in the same manner as in S404 of Fig. 4. Then, STA 103 responds by sending Message 2 to AP 102 (S602), in the same manner as in S405 of Fig. 4. In response, AP 102 and STA 103 update the GTKs for Link 1 and Link 2, and AP 102 resets the timers for updating the GTKs for Link 1 and Link 2.

[0045] Thereafter, for example, it is assumed that STA 103 decides to add a link (for example, by an instruction from an application or a user operation). In this case, STA 103 transmits an Add Link Request indicating a request to add Link 3 to AP 102 (S603). Upon receiving the Add Link Request, AP 102 transmits a GKHS processing message 1 (GKHS Msg1) to STA 103, which includes three MLO GTKs KDE corresponding to Link 1 to Link 3, respectively (S604). Note that this message 1 is transmitted even if the timing for updating the GTKs for Link 1 and Link 2 has not yet arrived. Upon receiving this message 1, STA 103 responds by transmitting a message 2 to AP 102 (S605). In response, AP 102 and STA 103 update the GTKs for Link 1 and Link 2 and set the GTK for Link 3. In addition, the AP 102 resets the timers for updating the GTK for link 1 and link 2, and starts the timer for updating the GTK for link 3.

[0046] As described above, in the process of Figure 6, when a link addition request is received, the GTKs of other links are updated at the GTK setting timing of the added link, even if the GTK update timing for each link has not yet arrived. This process simultaneously resets the GTK update timers for all links, allowing subsequent GTK update timing to be synchronized between links. As a result, as explained in relation to Figures 4 and 5, the frequency of sending and receiving messages for GKHS processing during GTK updates can be reduced, making it possible to update GTKs while reducing the waste of wireless resources.

[0047] While the process when a link is added has been described using FIG. 6, the process when a link is deleted may be performed in a similar manner. For example, assume that the update periods of Link 1 and Link 2 are determined based on the GTK update period of Link 3, and Link 3 is deleted. In this case, in order to adjust the update periods of Link 1 and Link 2, the GTK may be updated and the timer may be reset for Link 1 and Link 2. At this time, the update period may be reset. Furthermore, when deleting a link, links whose GTK update timing matches the update timing of many other links may not be deleted, and links whose update timing matches the update timing of fewer other links may be deleted with priority.

[0048] (GTK update interval setting process flow) Next, the process of setting the GTK update interval executed by AP 102 will be described. The GTK update interval can be set by a first method, as shown in FIGS. 4 and 6, in which the length of one update interval for multiple links is determined and that length is set for all links. Alternatively, the GTK update interval can be set by a second method, as shown in FIG. 5, in which the update interval for some of the multiple links is set to a length that is a multiple or divisor of the update interval for the other links. These methods can be implemented, for example, by the control unit 202 executing a program stored in the storage unit 201. However, this is merely an example, and at least a portion of these processes may be executed by dedicated hardware.

[0049] 7 shows an example of the processing flow when the AP 102 sets the GTK update interval using the first method. The processing in FIG. 7 starts, for example, when the user accesses the AP 102 using an application such as a web browser and displays a screen for setting the GTK update interval.

[0050] In this process, the AP 102 accepts user input specifying a GTK setting interval common to all links (S701). Here, the user may be able to arbitrarily set the update interval value with a resolution such as "seconds" or "minutes," or may be able to select only from update interval value candidates displayed in a drop-down list, etc. Upon accepting the user input, the AP 102 sets the entered GTK update interval as the GTK update interval for all established links (S702). This allows the GTK update timing of multiple links to be synchronized, reducing the number of messages sent and received for GTK updates and suppressing waste of wireless resources, as in the examples of Figures 4 and 6.

[0051] Fig. 8 shows an example of the processing flow when the AP 102 sets the GTK update interval using the second method. The processing in Fig. 8 is also started, for example, when the user accesses the AP 102 using an application such as a web browser and displays a screen for setting the GTK update interval.

[0052] In this process, the AP 102 first accepts a user's selection of a link for which the GTK update interval should be set from among multiple links (S801). The AP 102 then determines whether the GTK update intervals have been set for other links other than the selected link (S802). If the AP 102 determines that the GTK update intervals have not been set for any of the other links (NO in S802), the AP 102 accepts a user input specifying a GTK update interval value and sets the GTK update interval for the selected link to the input value (S803). On the other hand, if the AP 102 determines that the GTK update intervals have been set for other links (YES in S802), the AP 102 displays values ​​that are multiples or divisors of the set update interval length as candidates for the GTK update interval length for the selected link (S804). The AP 102 then accepts a user operation specifying one of the candidates displayed in S804 and sets the specified value as the GTK update interval for the selected link (S805). After the processing of S803 or S805, the AP 102 determines whether the setting of the GTK update interval has been completed for all links (S806). If there are any links for which the setting has not been completed (NO in S806), the AP 102 returns the processing to S801, and if the setting has been completed for all links (YES in S806), the AP 102 ends the processing of FIG.

[0053] 9 shows the transition of the GTK update interval setting screen displayed by AP 102 when the GTK update interval setting process of FIG. 8 is performed. FIG. 9 shows an example of the screen when setting the GTK update interval for three links. Note that this setting screen may be a screen that AP 102 displays on the display of a PC, smartphone, or the like when a user accesses AP 102 using the PC, smartphone, or the like. Furthermore, if AP 102 has a display such as a touch panel, this setting screen may be displayed on that display.

[0054] Screen 901 shows a state in which the GTK update interval has not been set for any link. When the user selects "Link 1 GTK Update Interval" on screen 901, for example, the area corresponding to "Link 1 GTK Update Interval" is highlighted. If the user then enters "30" (in this example, the unit is "seconds") as the GTK update interval for Link 1, the setting screen changes to screen 902. This sets the GTK update interval for Link 1. Next, assume that the user selects "Link 2 GTK Update Interval." Since the GTK update interval for Link 1 has already been set, a list of divisors and multiples of the value "30" set for Link 1 is displayed as candidates for the GTK update interval for Link 2. Screen 903 shows the setting screen in this state. The user can then select one of these displayed values ​​to set the GTK update interval for Link 2. This allows for the GTK update timing of multiple links to be synchronized, reducing the number of messages sent and received for GTK updates and suppressing waste of wireless resources, as in the example of FIG. 5.

[0055] (Communication control flow) Next, an example of the flow of control processing when AP 102 communicates with STA 103 will be described with reference to Fig. 10. The processing in Fig. 10 is started, for example, when AP 102 receives a connection request from STA 103. Note that this control processing can be realized, for example, by control unit 202 executing a program stored in storage unit 201. However, this is merely an example, and at least a part of the processing may be executed by dedicated hardware.

[0056] In FIG. 10, the AP 102 first determines whether it has received an Association Request frame including a Multi-link element from the STA 103 (S1001). The AP 102 then executes association processing and 4WHS processing with the STA 103 (S1002, S1003). The AP 102 generates a GTK during the 4WHS processing. If the AP 102 determines that it has received an Association Request frame that does not include a Multi-link element (NO in S1001), it can recognize that a single link will be used. Therefore, in this case, the AP 102 generates a single GTK for that single link (S1003). On the other hand, if the AP 102 determines that it has received an Association Request frame that includes a Multi-link element (YES in S1001), it can recognize that multiple links will be used. In this case, the AP 102 generates a GTK for each of the multiple links specified in the Multi-link element (S1003). Based on the GTK generated by these processes, the AP 102 resets and starts the GTK update timers for all links (S1004), and communication between the AP 102 and the STA 103 is then started.

[0057] The AP 102 determines whether it has received a Disassociation Request frame or a Disassociation Request frame from the STA 103 to disconnect the connection (to terminate communication on all links) (S1005). If the connection is to be disconnected (YES in S1005), the AP 102 executes the disconnection process and ends this process. On the other hand, while the connection is not disconnected (NO in S1005), the AP 102 monitors whether any of the links used for communication have reached the GTK update timing (S1006). In parallel with this monitoring, the AP 102 also monitors whether an Add Link Request frame has been received from the STA 103 to request the addition of a link (S1007). While there are no links that have reached the GTK update timing (NO in S1006) and no request to add a link has been made (NO in S1007), the AP 102 continues monitoring S1005 to S1007. When a request to add a link is made (YES in S1007), AP102 generates a GTK for the link to be added, and also generates GTKs for other links in use (S1008). If there is a link that has reached the time to update its GTK (YES in S1006), or if GTKs have been generated for all links in use and the link to be added in S1008, the process of S1009 is then executed.

[0058] In S1009, AP 102 transmits GKHS Msg1 containing the MLO GTK KDE for each link for which the GTK is to be updated to STA 103. AP 102 then waits to receive a GKHS Msg2 frame, which is a response to GKHS Msg1 (S1010). If AP 102 does not receive GKHS Msg2 within a predetermined period of time (NO in S1010), for example, AP 102 retransmits GKHS Msg1 (S1009). If AP 102 receives GKHS Msg2 (YES in S1010), AP 102 updates the GTK for each link for which the GTK is to be updated (S1011), resets the GTK update timer (S1012), and returns the process to S1005.

[0059] In this way, the number of messages sent when updating the GTK for multiple links can be reduced, thereby enabling efficient GTK updates while suppressing waste of wireless resources. As a result, efficient wireless communication can be achieved in a wireless communication system capable of configuring multiple links. When updating setting values ​​used for each of multiple links, a single message containing information about each of the links whose update timing for the setting value coincides can be transmitted, thereby enabling efficient setting value updates. By performing the above-described process to synchronize the update timing of the setting values, such setting value updates can be more easily performed, thereby further improving efficiency. In the above-described embodiment, an example was shown in which at least some of the GTK update timings coincide for all of the multiple links established between the AP 102 and the STA 103. However, this is not limited to this. That is, the above-described process may be performed for two or more of the multiple links. That is, for the two or more links whose update timings coincide as described above, the GTKs may be simultaneously updated using a single message, and control may be performed to synchronize the update timings.

[0060] In the above embodiment, the AP 102 completes the GTK update upon receiving GKHS Msg2 after transmitting GKHS Msg1. However, this is not limiting. That is, the AP 102 may transmit GKHS Msg1 or a corresponding message including GTKs or corresponding encryption keys for multiple links, and complete the encryption key update upon transmission. For example, if the communication quality of the link between the AP 102 and the STA 103 is sufficient, the STA 103 can almost certainly receive GKHS Msg1 or a corresponding message from the AP 102. Therefore, transmission of GKHS Msg2 or a corresponding message by the STA 103 may be omitted.

[0061] Although the above-described embodiment has been described primarily with a focus on the AP 102, the above-described processing of the AP 102 may be performed by the STA 103. Furthermore, the processing of generating an update message containing GTK information for multiple links as described above may be performed by an information processing device, such as a wireless chip, capable of performing wireless communication in accordance with the IEEE 802.11be standard. That is, the above-described AP 102 may be interpreted as an information processing device. Note that the information processing device, such as a wireless chip, may have an antenna for transmitting the generated signal. Furthermore, for example, when two STAs communicate using multiple links, the GTK update may be controlled by a control device different from the two STAs. In one example, the control device may transmit a single message to the two STAs to update the GTK for each of the multiple wireless links. In this case, by performing the above-described processing to synchronize the update timing for the multiple links, such updates may be more easily performed, thereby further improving efficiency.

[0062] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0063] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0064] 102: Access point (AP), 103: Station (STA), 302: GTK update interval input unit, 304: GTK update interval control unit, 305: GTK update request frame generation unit

Claims

1. A communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, A means for establishing a first link using a first frequency channel with other communication devices, After establishing the first link by the establishment means, a receiving means receives a Request from the other communication device that includes information requesting the addition of a new second link to the first link, It has, A communication device characterized in that, after receiving the Request, it transmits to the other communication device, in the first link, first information which associates the identification information of the second link with a first encryption key to be applied to the second link.

2. A communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, A means for establishing a first link using a first frequency channel with other communication devices, A transmission means that, after establishing the first link by the establishment means, transmits a Request to the other communication device containing information requesting the addition of a new second link to the first link, It has, A communication device characterized in that, after transmitting the Request, it receives from the other communication device, in the first link, first information relating the identification information of the second link to a first encryption key to be applied to the second link.

3. The communication device according to claim 1 or 2, characterized in that the identification information of the second link is the Link ID of the second link.

4. The communication device according to any one of claims 1 to 3, characterized in that the first encryption key is an encryption key for broadcast communication or multicast communication.

5. The communication device according to any one of claims 1 to 3, characterized in that the first encryption key is an encryption key managed for each link.

6. The communication device according to any one of claims 1 to 5, characterized in that the first information is MLO GTK KDE.

7. The communication device according to any one of claims 1 to 6, characterized in that the first frequency channel is a channel using one of the frequency bands from the 2.4 GHz band, the 5 GHz band, the 6 GHz band, and the 60 GHz band.

8. The communication device according to any one of claims 1 to 7, further comprising means for transmitting first data to another communication device via the first link and transmitting the same second data as the first data via the second link, after establishing the first link by the establishing means.

9. The communication device according to any one of claims 1 to 7, further comprising means for transmitting first data to another communication device via the first link and transmitting second data different from the first data via the second link, after establishing the first link by the establishing means.

10. After establishing the first link using the establishment means, to the other communication device, The second data, which is part of the first data, is transmitted via the first link. The communication device according to any one of claims 1 to 7, further comprising means for transmitting a third data, which is part of the first data and is different from the second data, via the second link.

11. The communication device according to any one of claims 1 to 10, characterized in that the establishing means establishes the first link by communicating an Association Request frame and an Association Response frame in the first frequency channel.

12. The communication device according to any one of claims 1 to 11, further comprising means for communicating a 4-Way Handshake message in the first frequency channel.

13. A control method performed by a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, A link establishment step is to establish a first link using a first frequency channel with other communication devices. A receiving step is to receive a Request from the other communication device that, after establishing the first link by the establishment step, includes information requesting the addition of a new second link to the first link. It has, A control method characterized by, after receiving the Request, transmitting to the other communication device, in the first link, first information that associates the identification information of the second link with a first encryption key to be applied to the second link.

14. A control method performed by a communication device that performs wireless communication in accordance with the IEEE 802.11 standard series, A link establishment step is to establish a first link using a first frequency channel with other communication devices. A transmission step of transmitting a Request to the other communication device, which includes information requesting the addition of a new second link to the first link, after the first link has been established by the establishment step, It has, A control method characterized in that, after transmitting the Request, the first link receives from the other communication device first information, which associates the identification information of the second link with a first encryption key to be applied to the second link.

15. A program for causing a computer to function as a communication device according to any one of claims 1 to 12.

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