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

Abstract

The communication device establishes a second radio link with a partner device in communication in addition to a first radio link already established, using information obtained through an authentication process performed when establishing the first radio link.

Description

Technical Field

[0001] This invention relates to link establishment techniques in wireless communication using multiple links. Background Technology

[0002] The IEEE 802.11 standard family is known as a wireless LAN communication standard defined by the IEEE (Institute of Electrical and Electronics Engineers). LAN is an abbreviation for Local Area Network. The IEEE 802.11 standard family includes standards such as IEEE 802.11a / b / g / n / ac / ax. Among these standards, the IEEE 802.11ax standard implements wireless communication via OFDMA (Orthogonal Frequency Division Multiple Access) (see PTL 1). This allows wireless communication devices conforming to the IEEE 802.11ax standard to perform communications with high peak throughput.

[0003] To further improve throughput or frequency utilization efficiency, the IEEE 802.11be standard has been considered as a new standard in the IEEE 802.11 series. For example, the IEEE 802.11be standard has explored the use of multi-link communication, in which an AP (Access Point) establishes multiple radio links with a STA (Station) via multiple different frequency channels to perform wireless communication simultaneously.

[0004] Reference List

[0005] Patent documents

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

[0007] Technical issues

[0008] This invention provides a technique for efficiently establishing multiple radio links in multi-link communication.

[0009] Solution to the problem

[0010] According to one aspect of the present invention, a communication device is provided capable of performing multilink communication conforming to the IEEE 802.11 standard series. The communication device includes: a control unit configured to, when the communication device establishes a first radio link and a second radio link with another communication device to perform the multilink communication, perform an association process in the executed radio link for generating a pairwise master key (PMK), but not perform the generation process in the other link, the pairwise master key (PMK) being an encryption key used for authentication with the other communication device; and an establishment unit configured to establish the first radio link and the second radio link using the PMK generated in the generation process.

[0011] Beneficial effects of the invention

[0012] According to the present invention, multiple radio links can be established efficiently in multi-link communication.

[0013] Other features and advantages of the invention will become clear from the following description taken in conjunction with the accompanying drawings. It should be noted that throughout the drawings, the same reference numerals denote the same or identical components. Attached Figure Description

[0014] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0015] Figure 1 This is a diagram illustrating an example of network configuration.

[0016] Figure 2 This is a block diagram illustrating an example of the hardware layout of a communication device.

[0017] Figure 3 This is a block diagram illustrating an example of the functional arrangement of a communication device.

[0018] Figure 4 This is a sequence diagram used to illustrate the process of establishing a multi-link connection.

[0019] Figure 5 This is a flowchart illustrating an example of the link establishment process performed by the STA; and

[0020] Figure 6 This is a flowchart illustrating an example of the link establishment process performed by the AP. Detailed Implementation

[0021] In the following, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claimed invention. Several features are described in the embodiments, but the invention is not limited to requiring all such features, and multiple such features can be suitably combined. Furthermore, in the drawings, the same reference numerals are given to the same or similar configurations, and repeated descriptions thereof are omitted.

[0022] (Network Configuration)

[0023] Figure 1 An example configuration of a wireless communication network according to this embodiment is shown. The wireless communication network is, for example, network 101 created by communication device 102, and network 101 is, for example, a wireless LAN (Local Area Network). Communication device 102 is configured to operate as an access point for the wireless LAN, acting as the creator of network 101. Note that the access point will sometimes be referred to as an "AP" below. In this embodiment, when multiple networks are created, communication device 102 sets the same BSSID for all networks. Note that BSSID is an abbreviation for Basic Service Set Identifier and is an identifier used to identify a network. Furthermore, communication device 102 sets a shared SSID as the SSID indicated in each network. SSID is an abbreviation for Service Set Identifier and is an identifier used to identify the access point. That is, even when communication device 102 establishes multiple connections according to this embodiment, a single SSID is used. Communication device 103 is a station with the role of joining network 101. Note that the site will sometimes be referred to as "STA" in the following text.

[0024] Note that, Figure 1 Only one AP is shown, but two or more APs can create a network separately. Furthermore, Figure 1 Only one STA is shown, but one or more STAs can join a network created by each of one or more APs.

[0025] Communication devices 102 and 103 support the IEEE 802.11be (EHT) standard and can perform wireless communication compliant with the IEEE 802.11be standard via network 101. Note that IEEE is an acronym for the Institute of Electrical and Electronics Engineers. EHT is an acronym for Extremely High Throughput. Communication devices 102 and 103 can perform communication in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. Note that the frequency bands used by communication devices 102 and 103 are not limited to these, and different frequency bands, such as the 60 GHz band, can be used. Communication devices 102 and 103 can use bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz for communication.

[0026] When a link is established between the AP and STA, user authentication is performed on the STA, and a PMK (Pairwise Master Key) is generated as the base key for an encrypted temporary key to be used for communication between the STA and AP. In the IEEE 802.11 standard family, WPA-Enterprise EAP (Extensible Authentication Protocol) authentication can be used as a user authentication method for enterprise wireless LANs. In EAP authentication, the authentication server performs user authentication, and several EAP messages need to be exchanged between the STA, AP, and authentication server. In this embodiment, authentication server 106 is configured to perform EAP authentication when a link is established between communication devices 102 and 103. Authentication server 106 is connected to communication device 102 via, for example, a wired or wireless line. If the EAP authentication by authentication server 106 is successful, then the PMK, which serves as the base key for an encrypted temporary key to be used for communication between communication devices 102 and 103, is generated by communication device 103 and authentication server 106. Authentication server 106 then notifies communication device 102 of the generated PMK.

[0027] Communication devices 102 and 103 can perform multi-user (MU) communication by multiplexing signals from multiple users through OFDMA communication conforming to the IEEE 802.11be standard. OFDMA is an acronym for Orthogonal Frequency Division Multiple Access. In OFDMA communication, frequency resource elements (RUs) are prepared, each with a predetermined frequency bandwidth obtained by dividing the entire frequency band. Each of these frequency resource elements includes a predetermined number of carriers, and the carriers are orthogonal to each other. Non-overlapping RUs are assigned to one or more STAs. This allows the AP to communicate with multiple STAs simultaneously.

[0028] Furthermore, communication devices 102 and 103 are configured to perform multi-link communication, in which links are established via multiple frequency channels to perform communication. Note that the frequency channels in this example refer to frequency channels defined in the IEEE 802.11 standard series and capable of performing wireless communications compliant with the IEEE 802.11 standard series. In the IEEE 802.11 standard series, the 2.4 GHz, 5 GHz, and 6 GHz frequency bands are prepared as usable frequency bands, and multiple frequency channels are defined in each of the usable frequency bands. In the IEEE 802.11 standard series, the bandwidth of each frequency channel is defined as 20 MHz. Note that by combining adjacent frequency channels, a bandwidth of 40 MHz or more can be used in a single frequency channel.

[0029] For example, communication devices 102 and 103 can establish a first radio link 104 using a first frequency channel and a second radio link 105 using a second frequency channel, and communicate with each other via these two links. In this case, communication device 102 maintains the first radio link 104 using the first frequency channel while maintaining the second radio link 105 using the second frequency channel. When communication device 102 establishes multiple radio links using multiple frequency channels with communication device 103, as described above, the throughput of communication with communication device 103 can be increased. Note that in multi-link communication, communication devices 102 and 103 can establish multiple radio links in different frequency bands or multiple radio links in the same frequency band. For example, communication devices 102 and 103 can establish a first radio link 104 in the 2.4 GHz band and a second radio link 105 in the 5 GHz band and communicate with each other. In addition to the first radio link 104 and the second radio link 105, communication devices 102 and 103 can also establish a third radio link in the 6 GHz band. Alternatively, communication devices 102 and 103 can establish a first radio link 104 using channel 1 in the 2.4 GHz band and a second radio link 105 using channel 5 in the 2.4 GHz band. Note that communication devices 102 and 103 can combine multiple radio links in the same frequency band and radio links in different frequency bands. For example, in addition to the first radio link 104 using channel 1 in the 2.4 GHz band and the second radio link 105 using channel 5 in the 2.4 GHz band, communication devices 102 and 103 can also establish a third radio link using channel 36 in the 5 GHz band. When communication device 102 establishes multiple connections with communication device 103 in different frequency bands, even in the event of congestion in a given frequency band, communication device 102 can use another frequency band to communicate with communication device 103. Therefore, when communication devices 102 and 103 establish multiple radio links in multiple frequency bands to communicate with each other, a decrease in the throughput of communication with communication device 103 can be prevented.

[0030] In multi-link communication, the multiple radio links established by communication devices 102 and 103 are configured to use at least different frequency channels. Note that in multi-link communication, the channel spacing between the frequency channels of the multiple radio links established by communication devices 102 and 103 is set to at least 20 MHz or more. Note that in the example above, communication devices 102 and 103 establish a first radio link 104 and a second radio link 105, but three or more radio links can be established.

[0031] When performing multi-link communication, each of communication devices 102 and 103 can transmit data or multiple data obtained by segmenting one data to a partner device via multiple radio links. Each of communication devices 102 and 103 can transmit the same data via each of the multiple radio links. Therefore, communication via one link can be performed as a backup communication for communication via another link. For example, suppose communication device 102 transmits the same data to communication device 103 via a first radio link using a first frequency channel and a second radio link using a second frequency channel, and an error occurs in the communication via the first radio link. In this case, since the same data is transmitted via the second radio link, communication device 103 can receive the data transmitted from communication device 102 via the second radio link instead of the first radio link.

[0032] Communication devices 102 and 103 can use each radio link depending on the type of frame or data to be transmitted. For example, when transmitting data about captured images, communication device 102 can transmit metadata such as date, parameters at the time of image capture (aperture value and shutter speed), and location information via a first radio link and transmit pixel information via a second radio link. Communication device 102 can transmit management frames via the first radio link and data frames including data via the second radio link. Note that management frames include, for example, beacon frames, probe request / response frames, and association request / response frames. Furthermore, management frames can include deassociation frames, authentication frames, deauthentication frames, and action frames. Beacon frames are frames that notify of network information. Probe request frames are frames that request network information, and probe response frames are responses to probe request frames and provide network information. Association request frames are frames that request connection, and association response frames are responses to association request frames and indicate whether connection is allowed or not. Deassociation frames are frames used to disconnect. Authentication frames are frames used to authenticate partner devices. Deauthentication frames are frames used to interrupt the authentication of partner devices and disconnect the connection. Action frames are frames used to perform additional functions beyond those described above. Communication devices 102 and 103 are configured to send / receive management frames conforming to the IEEE 802.11 standard series, such as the frames described above.

[0033] Communication devices 102 and 103 can be configured to perform MIMO (Multiple-Input and Multiple-Output) communication. In this configuration, each of communication devices 102 and 103 includes multiple antennas, and one of the communication devices transmits different signals generated from multiple streams from the respective antennas using the same frequency channel. The receiving-side communication device uses the multiple antennas to simultaneously receive all signals arriving from the multiple streams, separate the signals from these streams, and decode them. Compared to not performing MIMO communication, communication devices 102 and 103 can transmit more data simultaneously by performing MIMO communication. Furthermore, when performing multi-link communication, communication devices 102 and 103 can perform MIMO communication in some or all of the links.

[0034] Note that in the above example, each of communication devices 102 and 103 supports the IEEE 802.11be standard. In addition, each of communication devices 102 and 103 may also support at least one of the legacy standards defined prior to the IEEE 802.11be standard. Legacy standards include the IEEE 802.11a / b / g / n / ac / ax standards. Note that in this embodiment, "IEEE 802.11 standard family" refers to at least one of the IEEE 802.11a / b / g / n / ac / ax / be standards. Besides the IEEE 802.11 standard family, each of communication devices 102 and 103 may also support standards such as... NFC, UWB This is another communication standard, MBOA. Note that UWB is an abbreviation for UltraWide Band, and MBOA is an abbreviation for Multi Band OFDM Alliance. Note that OFDM is an abbreviation for Orthogonal Frequency Division Multiplexing. Additionally, NFC is an abbreviation for Near Field Communication. UWB includes Wireless USB, Wireless 1394, and Wine. Furthermore, each of communication devices 102 and 103 can support communication standards such as wired LAN.

[0035] Communication device 102 can be, for example, a wireless LAN router, a PC (Personal Computer), etc. However, communication device 102 is not limited to these and can be any communication device capable of performing multi-link communication with another communication device. Communication device 103 can be, for example, a camera, tablet computer, smartphone, PC, mobile phone, video camera, etc. However, communication device 103 is not limited to these and can be any communication device capable of performing multi-link communication with another communication device. Note that the components and functions described with respect to communication devices 102 and 103 in this embodiment can be performed by an information processing device such as a radio chip capable of performing wireless communication conforming to the IEEE 802.11be standard. Also note that the information processing device such as a radio chip may include an antenna for transmitting generated signals.

[0036] As described above, communication devices 102 and 103 perform multi-link communication. In this case, with EAP authentication performed each time a link is established in multi-link communication, the overhead of exchanging EAP messages is high, and establishing a connection takes time. Therefore, considering the above problems, communication devices 102 and 103 in this embodiment perform processing for efficiently establishing multiple links. The arrangement of communication devices 102 and 103 and examples of the processing procedures performed by these communication devices will be described below.

[0037] (Arrangement of communication equipment)

[0038] Figure 2 The hardware arrangement of a communication device 102 according to this embodiment is shown. The communication device 102 includes a storage unit 201, a control unit 202, a functional unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207. Note that... Figure 2 The arrangement shown schematically illustrates at least some of the functions of communication device 102, and communication device 102 may of course include other components. Communication device 103 has the same hardware arrangement as communication device 102, and its description will be omitted.

[0039] Storage unit 201 is formed by one or more memories such as ROM and RAM, and stores computer programs for performing various operations (described later), as well as various information such as communication parameters for wireless communication. ROM is an abbreviation for Read Only Memory, and RAM is an abbreviation for Random Access Memory. In addition to memories such as ROM or RAM, storage unit 201 may also include storage media such as floppy disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, or DVDs. Storage unit 201 may include multiple memories.

[0040] The control unit 202 comprises one or more processors, such as a CPU and an MPU, and controls the entire communication device 102 by executing a computer program stored in the storage unit 201. Note that the control unit 202 can be configured to control the entire communication device 102 through the cooperation of an OS (Operating System) and the computer program stored in the storage unit 201. The control unit 202 generates data or signals (radio frames) to be transmitted in communication with another communication device. Note that CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. The control unit 202 may include multiple processors, such as a multi-core processor, and controls the entire communication device 102 through these multiple processors. Furthermore, the control unit 202 controls the functional unit 203 to perform wireless communication or predetermined processing, such as image capture, printing, or projection processing. The functional unit 203 is, for example, hardware used by the communication device 102 to perform the predetermined processing.

[0041] Input unit 204 receives various operations from the user. Output unit 205 performs various outputs to the user via a monitor screen or speaker. In this example, the output of output unit 205 may include, for example, the display of visual output (e.g., an image on the monitor screen), audio output from the speaker, and vibration output. Note that both input unit 204 and output unit 205 can be implemented as a single module, such as a touch panel. Furthermore, each of input unit 204 and output unit 205 can be integrated with communication device 102 or detachable from communication device 102.

[0042] Communication unit 206 controls wireless communication conforming to the IEEE 802.11be standard. Communication unit 206 can control wireless communication conforming to another standard in the IEEE 802.11 standard family besides IEEE 802.11be, or control wired communication via wired LAN, etc. Communication unit 206 controls antenna 207 to send / receive signals for wireless communication generated by control unit 202. Note that if communication device 102 also supports NFC or Bluetooth standards in addition to the IEEE 802.11be standard, communication unit 206 can control wireless communication conforming to these communication standards. Also note that if communication device 102 can perform wireless communication conforming to each of multiple communication standards, it may include communication unit 206 and antenna 207 supporting each communication standard. Communication device 102 sends / receives data such as image data, document data, or video data to / from communication device 103 via communication unit 206.

[0043] Antenna 207 is an antenna that allows communication in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. In this embodiment, communication device 102 includes one antenna, but may include antennas different for each frequency band. If communication device 102 includes multiple antennas, it may include multiple communication units 206, each corresponding to an antenna. Note that antenna 207 may be configured as a module integrated with communication unit 206, or it may be prepared separately from communication unit 206.

[0044] Figure 3 An example of the functional arrangement of a communication device 102 according to this embodiment is shown. For example, the communication device 102, as a functional arrangement, includes a link establishment unit 301, an encryption key management unit 302, a MAC frame generation unit 303, and a data transmission / reception unit 304. Note that... Figure 3 The arrangement shown schematically illustrates the functions associated with this embodiment, and the communication device 102 may of course include the general functions of the communication device 102 as well as other functions corresponding to the application purpose of the communication device 102. The communication device 103 has the same functional arrangement as the communication device 102, and its description will be omitted.

[0045] Link establishment unit 301 performs processes for establishing one or more radio links to be used by communication device 102 to perform data communication with communication device 103. Link establishment processes include, for example, authentication processing, association processing, EAP authentication processing, and four-way handshake (4WHS) processing. If EAP authentication is successful, a PMK is generated by communication device 103 and authentication server 106 as the basis for an encrypted temporary key to be used for communication between communication devices 102 and 103, and authentication server 106 notifies communication device 102 of the generated PMK. The PMK is used to generate a temporary encryption key in the 4WHS process. Link establishment unit 301 can perform multiple radio link connection processes in advance when establishing a connection with communication device 103, or it can perform another radio link connection process later during communication using predetermined radio links.

[0046] The encryption key management unit 302 manages the PMK obtained by the link establishment unit 301, as well as encryption keys such as temporary keys (e.g., PTK or GTK generated in the 4WHS process). The encryption key management unit 302 also manages the PMKID, which associates the PMK with the partner device's ID. The PMKID is identification information corresponding to the PMK. This management allows the encryption key management unit 302 to identify the corresponding PMK by specifying the partner device's ID and PMKID. The MAC frame generation unit 303 generates various management frames, such as association request / response frames, and MAC frames included in data frames, etc. The data transmission / reception unit 304 transmits radio frames including the MAC frames generated by the MAC frame generation unit 303, and receives radio frames from partner devices.

[0047] (Processing procedure)

[0048] Subsequently, an example of the processing performed by communication devices 102 and 103 will be described. Figure 4 An example of messages sent / received by communication devices 102 and 103 is shown. This example illustrates the use of two radio links. Communication processing using a first frequency channel (e.g., channel 1 in the 2.4 GHz band) is performed in the first radio link, and communication processing using a second frequency channel (e.g., channel 36 in the 5 GHz band) is performed in the second radio link. Note that in... Figure 4For convenience, in communication device 102, the function of performing communication using a first frequency channel in a first radio link is represented by AP 1, and the function of performing communication using a second frequency channel in a second radio link is represented by AP 2. Similarly, in communication device 103, the function of performing communication using a first frequency channel in a first radio link is represented by STA 1, and the function of performing communication using a second frequency channel in a second radio link is represented by STA 2. Each of communication devices 102 and 103 can be configured to simultaneously perform communication using two or more frequency channels through physically different communication circuits, etc. Each of communication devices 102 and 103 can logically implement multiple AP functions or multiple STA functions using shared communication circuits, etc. Communication devices 102 and 103 can physically and logically establish multiple radio links simultaneously using the functions of one AP and one STA, thereby communicating with each other.

[0049] This process begins, for example, when each of communication devices 102 and 103 is powered on. This process can also begin when a user or application in at least one of communication devices 102 and 103 instructs the initiation of multi-link communication. Furthermore, this process can begin when the amount of data to be transmitted with a partner device in at least one of communication devices 102 and 103 becomes equal to or greater than a predetermined amount. Note that... Figure 4 Only some of the processes associated with this embodiment are shown, but of course, various processes (e.g., search request / response processing, etc.) in general wireless LAN connection methods are performed.

[0050] Communication devices 102 and 103 perform authentication processing for the first radio link in the first frequency channel (S401). For example, communication device 103 sends an authentication request frame for authentication to communication device 102, and communication device 102 sends an authentication response frame to communication device 103 as a response to the authentication request frame. Note that the SAE (Simultaneous Authentication Equal) method can be used as the authentication method. In this case, authentication request frames and authentication response frames are exchanged multiple times. Afterwards, communication devices 102 and 103 perform association processing for the first radio link (S402). For example, communication device 103 sends an association request frame for connection to communication device 102, and communication device 102 sends an association response frame to communication device 103 as a response to the association request frame. At this time, communication device 103 stores the MLDID (Multi-Link Device ID) as identification information of communication device 103 in the association request frame and sends the association request frame.

[0051] Subsequently, EAP frames, such as EAPOL-Start frames, are exchanged between communication devices 102 and 103 and authentication server 106 to perform EAP authentication (S403). If EAP authentication is successful, the PMK shared by communication devices 102 and 103 is maintained. Then, communication devices 102 and 103 perform 4WHS processing to generate a temporary key for encrypted communication (S404). As a result of this processing, communication devices 102 and 103 set the generated PTK as the encryption key to be used for unicast communication and the generated GTK as the encryption key to be used for multicast / broadcast communication in their radio chips. Each of communication devices 102 and 103 stores a PMKID associated with the ID and PMK of the partner device in a cache.

[0052] Subsequently, communication devices 102 and 103 perform the process of establishing a second radio link. This process can be performed immediately after the process of establishing the first radio link, or after a certain period of time since the establishment of the first radio link. In the process of establishing the second radio link, firstly, communication devices 102 and 103 perform authentication processing (S411) of the second radio link in the second frequency channel. For example, communication device 103 sends an authentication request frame for authentication to communication device 102, and communication device 102 sends an authentication response frame to communication device 103 as a response to the authentication request frame. Note that when the SAE method is used for authentication, the authentication request frame and authentication response frame are exchanged multiple times. Then, communication devices 102 and 103 perform association processing (S412) of the second radio link. For example, communication device 103 sends an association request frame for connection to communication device 102, and communication device 102 sends an association response frame to communication device 103 as a response to the association request frame. At this time, communication device 103 stores its own MLDID and the PMKID associated with communication device 102 in the association request frame and sends the association request frame. Upon receiving the association request frame, communication device 102 retrieves the PMK corresponding to the MLDID and PMKID from its cache. In this example, the PMK is maintained in the cache of communication device 102 through the processes in S403 and S404. Therefore, communication device 103 does not initiate EAP authentication, and communication device 102 initiates 4WHS processing (S413). Note that the processing in S413 is the same as the processing in S404.

[0053] Then, refer to Figure 5 This describes the link establishment process performed by the STA (communication device 103). Note that... Figure 5The process shown can be implemented, for example, when the control unit 202 of the STA executes a program stored in the storage unit 201. However, the invention is not limited thereto. For example, Figure 5 The process shown can be configured to perform Figure 5 The processing shown is implemented in dedicated hardware, such as a wireless communication chip. Alternatively, Figure 5 The processing shown can be implemented when a processor in, for example, the communication unit 206 of the STA executes a dedicated program.

[0054] First, the STA performs authentication processing with the AP (communication device 102) (step S501). Then, the STA determines whether another radio link has been established with the same AP and is in use (step S502). If no other radio link has been established with the same AP or it is not in use ("No" in step S502), the STA determines whether a radio link has been established with the AP in the past (step S503). Then, if there is a radio link in use with the AP that is the execution partner of the authentication processing ("Yes" in step S502) or a radio link has been established in the past ("Yes" in step S503), the STA proceeds to step S504. On the other hand, if the STA determines that no radio link has been established with the AP that is the execution partner of the authentication processing in the past ("No" in step S503), then the STA proceeds to step S505 and does not perform the processing in step S504. Note that the determination processes in steps S502 and S503 correspond to determining whether the PMK corresponding to the AP has been cached, and for example, it is not necessary to perform the process of determining whether a radio link has actually been established in the past. That is, past PMK information can be deleted after a given period of time, and an AP whose corresponding PMK information has been deleted can be regarded as an AP that "has not established a radio link with it in the past".

[0055] Note that the STA performs the process in step S503 not only when performing multi-link communication but also when performing single-link communication. That is, when the radio link is broken during communication by establishing a single link and then re-established, the STA performs the determination process in step S503. In this case, since a radio link that was previously established with the AP connected to the destination has been broken, the process proceeds to step S504.

[0056] In step S504, the STA has an established radio link with the AP or has previously established a radio link with the AP, and the PMK corresponding to that AP is cached. Therefore, the STA stores the PMKID in the association request frame. The PMKID is used to specify the PMK cached in the communication partner's AP. In step S505, the STA stores the MLDID used to identify its own device in the association request frame. Thereafter, the STA performs association processing using the set association request frame (step S506).

[0057] Subsequently, similar to steps S502 and S503, the STA determines whether an active radio link exists with the AP that has already performed authentication processing (step S507), and whether a radio link has been established in the past (step S508). If an active radio link exists with the AP ("Yes" in step S507) or a radio link has been established in the past ("Yes" in step S508), the STA proceeds to step S511 without performing the processes in steps S509 and S510. If the STA does not have an active radio link with the AP and has not established a radio link with the AP in the past ("No" in steps S507 and S508), the PMK is not cached. Therefore, the STA performs EAP authentication to generate a PMK (step S509) and saves the generated PMK in the cache (step S510). In step S511, the STA performs 4WHS processing with the AP that established the connection partnership, and saves the PMKID notified from the AP in the cache.

[0058] Note that this processing example illustrates how PMKID and MLDID are stored in an association request frame and sent to the AP. However, the invention is not limited to this. PMKID and MLDID can be stored in another frame, such as an authentication request frame, and sent to the AP.

[0059] Then, refer to Figure 6 This example describes the link establishment process performed by the AP (communication device 102). Note that... Figure 6 The process shown can be implemented, for example, when the control unit 202 of the AP executes a program stored in the storage unit 201. However, the invention is not limited thereto. For example, Figure 6 The process shown can be configured to perform Figure 6 The processing shown is implemented in dedicated hardware, such as a wireless communication chip. Alternatively, Figure 6 The processing shown can be implemented when the processor in the communication unit 206 of the AP executes a dedicated program.

[0060] First, the AP and STA (communication device 103) perform authentication processing (step S601). Next, the AP performs association processing to obtain the MLDID and PMKID used to identify the STA from the association request frame received from the connection partner STA. The AP checks whether the PMK corresponding to the STA's MLDID and PMKID is stored in the cache (step S603). If the PMK corresponding to the STA's MLDID and PMKID is not stored in the cache ("No" in step S603), the AP waits until EAP authentication is performed between the STA and the authentication server 106 (step S604). Then, the AP obtains the PMK obtained through EAP authentication from the authentication server 106 and stores the PMKID corresponding to the obtained PMK and the STA's MLDID in the cache (step S605). On the other hand, if the PMK corresponding to the STA's MLDID and PMKID is stored in the cache ("Yes" in step S603), the AP does not perform the processing in steps S604 and S605. Afterwards, AP and STA perform 4WHS processing and AP notifies STA of PMKID (step S606).

[0061] As described above, when communication devices 102 and 103 establish a second radio link while the first radio link is already established, EAP authentication for the second radio link is omitted. This prevents EAP authentication from being performed every time a radio link is established, and also prevents the connection time from being extended due to the overhead of exchanging EAP messages. This allows for the efficient establishment of multiple radio links compliant with the IEEE 802.11 standard series between the AP and STA.

[0062] It should be noted that the above embodiments are merely examples and various modifications can be made. For example, multi-link communication conforming to the IEEE 802.11 standard family has been explained, but the above processing can also be applied to multi-link communication conforming to another wireless communication standard. Furthermore, the above embodiments have explained an example of information obtained through EAP authentication being used in another radio link, but the same discussion can also be applied to predetermined authentication processes that include authentication processes other than EAP authentication. Note that the predetermined authentication process can be an authentication process performed via an external device such as authentication server 106, which is different from communication devices 102 and 103, or it can be an authentication process performed without the intervention of an external device.

[0063] This invention can be implemented by supplying a program for implementing one or more functions of the above embodiments to a system or device via a network or storage medium, and causing one or more processors in the computer of the system or device to read and execute the processing of the program. This invention can also be implemented by a circuit (e.g., an ASIC) for implementing one or more functions.

[0064] This invention is not limited to the above embodiments, and various changes and modifications can be made within the spirit and scope of this invention. Therefore, the appended claims are presented to inform the public of the scope of this invention.

[0065] This application claims priority to Japanese Patent Application No. 2020-083367, filed on May 11, 2020, which is hereby incorporated herein by reference.

Claims

1. A communication device capable of performing wireless communication conforming to the IEEE 802.11 standard series, the communication device comprising: A connection unit configured to perform association processing in a first radio link in order to establish a first radio link and a second radio link with another communication device; The first obtaining unit is configured to obtain a pairwise master key (PMK) by performing authentication processing using the Extensible Authentication Protocol (EAP) with an external authentication server different from the communication device and the other communication device, and with the other communication device in the first radio link where the association processing is performed, but not performing authentication processing using EAP in the second radio link. The second obtaining unit is configured to obtain a PTK based on a PMK generated by performing a four-way handshake (4WHS) process with the other communication device in the first radio link, wherein the PTK is an encryption key to be used for unicast communication; as well as A communication unit configured to control the use of a PTK generated based on the PMK in communications on the second radio link.

2. The communication device according to claim 1 further includes a holding unit, the holding unit being configured to hold the PMK obtained by the first obtaining unit as cached data.

3. The communication device according to claim 2, wherein, The holding unit is configured to also hold PMK ID and MLD ID information used to identify the other communication device.

4. The communication device according to claim 2, wherein, While the holding unit holds the PMK obtained by the first obtaining unit, the first obtaining unit does not perform authentication processing using EAP with the other communication device and the external authentication server.

5. The communication device according to claim 1, wherein, The communication device is a wireless LAN station conforming to the IEEE 802.11 standard series, and the other communication device is the access point of the wireless LAN. In the authentication process, the external authentication server performs user authentication based on the EAP message sent by the communication device.

6. The communication device according to claim 3, wherein, With the holding unit holding the PMK ID, the connection unit is configured to send an association frame including the PMK ID in the association process.

7. The communication device according to claim 6, wherein, The connection unit notifies the other communication device of the PMK ID and MLD ID information by including the PMK ID and MLD ID information in the association request during the association process.

8. The communication device according to claim 1, wherein, The communication device is an access point for a wireless LAN that conforms to the IEEE 802.11 standard series, and the other communication device is a site for the wireless LAN.

9. The communication device according to claim 3, wherein, While the holding unit holds the PMK ID, the connection unit sends an association frame including the PMK ID in the association process, and the first obtaining unit does not perform authentication processing using EAP with the other communication device and the external authentication server.

10. A computer-readable storage medium storing a program for operating a computer as a communication device as defined in any one of claims 1 to 9.

11. A control method executed by a communication device, the communication device being capable of performing wireless communication conforming to the IEEE 802.11 standard series, the control method comprising: In the first radio link, an association process is performed to establish the first radio link and the second radio link with another communication device; A pairwise master key (PMK) is obtained by performing authentication processing using the Extensible Authentication Protocol (EAP) with an external authentication server different from the other communication device and with the other communication device in the first radio link where the association processing is performed, but not by performing authentication processing using EAP in the second radio link. A PTK based on a PMK is obtained by performing a four-way handshake (4WHS) process with the other communication device in the first radio link, wherein the PTK is an encryption key to be used for unicast communication; as well as Control is performed to use the PTK generated based on the PMK in communications in the second radio link.

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