Communication device, communication method, and program

Abstract

To prevent normal data frames from being discarded when a communication device establishes a connection via multiple frequency channels.SOLUTION: In a state in which a communication device 102 and a communication device 103 have established a connection via a first frequency channel on a first link 104, it is determined whether the communication device 103 has established a connection via a second frequency channel on a second link 105, and if it is determined that the communication device 103 has established a connection via the second frequency channel, a cryptographic key common to communication via the first frequency channel and communication via the second frequency channel is set.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication device and a wireless communication method for performing wireless communication. [Background technology]

[0002] The IEEE802.11 series is known as the WLAN communication standard established by the IEEE (Institute of Electrical and Electronics Engineers). WLAN stands for Wireless Local Area Network. The IEEE802.11 series standards include the IEEE802.11a / b / g / n / ac / ax standards.

[0003] Patent Document 1 discloses that the IEEE802.11ax standard performs wireless communication using Orthogonal Frequency Division Multiple Access (OFDMA). The IEEE802.11ax standard achieves high peak throughput by performing wireless communication using OFDMA.

[0004] To further improve throughput and frequency utilization efficiency, the IEEE is considering the formulation of the IEEE802.11be standard as a new standard in the IEEE802.11 series. The IEEE802.11be standard is considering technology that enables faster wireless communication by allowing one access point (AP) to establish multiple wireless communication links with one station (STA) via multiple different frequency channels. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-50133 Summary of the Invention [Problem to be solved by the invention]

[0006] Data frames transmitted by a communication device are assigned an SN (Sequence Number), which indicates the order in which the data was transmitted. The SN is used to rearrange the data frames when the order in which the data frames arrive is changed on the receiving side. Furthermore, when transmitting data, a Pairwise Transient Key (PTK), which is an encryption key, is used. When a data frame is encrypted using the PTK, a Packet Number (PN) is assigned to the data frame. When rearranging data frames on the receiving side, if a data frame is received that has been assigned a PN that is smaller than the PN of a data frame that has already been received, this is determined to be a replay attack, and subsequent data frames are discarded.

[0007] When communication is performed via multiple frequency channels, for example, if an error occurs in a data frame transmitted over a first frequency channel, it is possible to switch to a second frequency channel with better communication quality and retransmit the data frame. In this case, if the PTK differs for each frequency channel, the PN added when encrypting the data frame will differ between frequency channels.

[0008] When rearranging data frames received via multiple frequency channels in order of SN, for example, there is a possibility that the PN of a data frame received via a second frequency channel will be smaller than the PN of a data frame previously received via a first frequency channel, which poses a problem of discarding normal data frames received via the second frequency channel.

[0009] In view of the above-mentioned problems, an object of the present invention is to prevent normal data frames from being discarded when a communication device establishes a connection via multiple frequency channels. [Means for solving the problem]

[0010] In order to achieve the above object, a communication device according to one aspect of the present invention comprises: A communication device, a first connection means for establishing a connection with another communication device via a first frequency channel; a second connection means for establishing a connection with another communication device via a second frequency channel while a connection is established by the first connection means; a determination means for determining whether the other communication device that establishes a connection via the first connection means and the other communication device that establishes a connection via the second connection means are the same communication device, based on identification information of the other communication device that establishes a connection via the first connection means and identification information of the other communication device that establishes a connection via the second connection means; a setting means for setting a common encryption key for communication via the first frequency channel and communication via the second frequency channel when the determination means determines that the communication devices are the same; It has. [Effects of the Invention]

[0011] According to the present invention, when communication is performed via a plurality of frequency channels, communication can be performed without discarding normal data frames. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the configuration of a network constructed by a communication device 102. [Figure 2] FIG. 2 is a diagram illustrating a hardware configuration of communication devices 102 and 103. [Figure 3] FIG. 2 is a diagram illustrating the functional configuration of communication devices 102 and 103. [Figure 4] FIG. 10 is a sequence diagram showing a multi-link connection process. [Figure 5] 10 is a flowchart showing a link connection process of the communication device 102. [Figure 6] 10 is a flowchart showing a first example of a link connection process of the communication device 103. [Figure 7] FIG. 10 is a sequence diagram showing a multi-link connection process. [Figure 8] 10 is a flowchart showing a link connection process of the communication device 102. [Figure 9] 10 is a flowchart showing a link connection process of the communication device 103. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

[0014] FIG. 1 shows the configuration of a network established by a communication device 102 according to this embodiment. The communication device 102 is an access point (AP) that establishes a network 101. The network 101 is a wireless network. In this embodiment, when the communication device 102 establishes multiple networks, the BSSIDs of the networks are all the same. BSSID stands for Basic Service Set Identifier and is an identifier for identifying a network. The SSIDs indicated by the communication device 102 in each network are also all the same. SSID stands for Service Set Identifier and is an identifier for identifying an access point. In this embodiment, the communication device 102 uses one SSID even when multiple connections are established.

[0015] Furthermore, the communication devices 103 are stations (STAs) that participate in the network 101. Each communication device is compatible with the IEEE 802.11be (EHT) standard and can perform wireless communication in accordance with the IEEE 802.11be standard via the network 101. Note that IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. Furthermore, EHT is an abbreviation for Extremely High Throughput. Note that EHT may also be interpreted as an abbreviation for Extreme High Throughput. Each communication device can communicate in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. The frequency bands used by each communication device are not limited to these, and a different frequency band, such as the 60 GHz band, may also be used. Furthermore, each communication device can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0016] The communication devices 102 and 103 perform OFDMA communication conforming to the IEEE802.11be standard, thereby realizing multi-user (MU) communication in which signals from multiple users are multiplexed. OFDMA communication stands for Orthogonal Frequency Division Multiple Access. In OFDMA communication, portions of the divided frequency band (RU, Resource Unit) are assigned to each STA so that they do not overlap, and the carriers assigned to each STA are orthogonal. This allows the AP to communicate with multiple STAs in parallel.

[0017] Furthermore, the communication devices 102 and 103 perform multi-link communication by establishing links via multiple frequency channels. Here, a frequency channel refers to a frequency channel defined in the IEEE 802.11 series of standards that can perform wireless communication compliant with the IEEE 802.11 series of standards. The IEEE 802.11 series of standards defines multiple frequency channels in each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. The IEEE 802.11 series of standards also defines a bandwidth of 20 MHz for each frequency channel. Note that a single frequency channel may utilize a bandwidth of 40 MHz or more by bonding adjacent frequency channels. For example, the communication device 102 can establish a first link 104 with the communication device 103 via a first frequency channel in the 2.4 GHz band and a second link 105 via a second frequency channel in the 5 GHz band, and communicate via both links. In this case, the communication device 102 maintains a second link 105 via a second frequency channel in parallel with a first link 104 via a first frequency channel. In this way, the communication device 102 can improve the throughput of communication with the communication device 103 by establishing links with the communication device 103 via multiple frequency channels. Note that the communication devices 102 and 103 may establish multiple links in different frequency bands in multi-link communication. For example, the communication devices 102 and 103 may establish a first link 104 in the 2.4 GHz band, a second link 105 in the 5 GHz band, and a third link in the 6 GHz band. Alternatively, links may be established via multiple different channels included in the same frequency band. For example, the first link 104 may be established via channel 1 in the 2.4 GHz band, and the second link 105 may be established via channel 5 in the 2.4 GHz band. Note that links in the same frequency band and links in different frequency bands may be mixed.For example, communication devices 102 and 103 may establish a first link 104 via channel 1 in the 2.4 GHz band, a second link 105 via channel 5 in the 2.4 GHz band, and a third link via channel 36 in the 5 GHz band. By establishing multiple connections with communication device 103 using different frequency bands, communication device 102 can communicate with communication device 103 using the other band even when one band is congested, thereby preventing a decrease in throughput in communication with communication device 103.

[0018] In multi-link communication, the multiple links established between the communication devices 102 and 103 need only have different frequency channels. Note that in multi-link communication, the channel spacing between the frequency channels of the multiple links established between the communication devices 102 and 103 needs only to be at least 20 MHz or greater. Note that in this embodiment, the communication devices 102 and 103 establish a first link 104 and a second link 105, but they may also establish three or more links.

[0019] When performing multi-link communication, the communication devices 102 and 103 divide a single piece of data and transmit it to the other device via multiple links. Alternatively, the communication devices 102 and 103 may transmit the same data via each of the multiple links, with communication via one link serving as a backup for communication via the other link. Specifically, the communication device 102 may transmit the same data to the communication device 103 via a first link via a first frequency channel and a second link via a second frequency channel. In this case, even if an error occurs in communication via the first link, the communication device 103 can receive the data transmitted from the communication device 102 because the same data was transmitted via the second link. Alternatively, the communication devices 102 and 103 may use different links depending on the type of frame or data to be communicated. For example, the communication device 102 may transmit a management frame via the first link and a data frame containing data via the second link. Management frames specifically refer to 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 their responses, providing network information. Association Request frames are frames that request a connection, and Association Response frames are their responses, indicating permission for the connection or an error. Disassociation frames are frames that cut off a connection.An authentication frame is a frame that authenticates a remote device, and a de-authentication frame is a frame that suspends authentication of the remote device and disconnects the connection. An action frame is a frame that performs additional functions other than those described above. The communication devices 102 and 103 send and receive management frames that comply with the IEEE 802.11 series standards. Alternatively, when transmitting data related to captured images, for example, the communication device 102 may transmit meta-information such as the date, parameters at the time of capture (aperture value and shutter speed), and location information via a first link, and transmit pixel information via a second link.

[0020] The communication devices 102 and 103 may also be capable of MIMO (Multiple-Input And Multiple-Output) communication. In this case, the communication devices 102 and 103 have multiple antennas, and one of them transmits different signals from each antenna using the same frequency channel. The receiving side simultaneously receives all signals arriving from multiple streams using multiple antennas, and separates and decodes the signals of each stream. By performing MIMO communication in this way, the communication devices 102 and 103 can communicate more data in the same amount of time than if they did not perform MIMO communication. Furthermore, when performing multi-link communication, the communication devices 102 and 103 may perform MIMO communication on some of the links.

[0021] Although the communication devices 102 and 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. The legacy standard refers to the IEEE 802.11a / b / g / n / ac / ax standards. In this embodiment, at least one of the IEEE 802.11a / b / g / n / ac / ax / be standards and their successor standards is referred to as the IEEE 802.11 series standard. In addition to the IEEE 802.11 series standard, the communication devices 102 and 103 may also be compatible with other communication standards, such as Bluetooth (registered trademark), NFC, UWB, Zigbee, and MBOA. UWB stands for Ultra Wide Band, and MBOA stands for Multi-Band OFDM Alliance. OFDM stands for Orthogonal Frequency Division Multiplexing. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, Wi-Fi, etc. It may also be compatible with wired communication standards such as wired LAN.

[0022] Specific examples of the communication device 102 include, but are not limited to, a wireless LAN router and a PC. The communication device 102 may be any communication device capable of performing multi-link communication with other communication devices. The communication device 102 may also be an information processing device, such as a wireless chip, capable of performing wireless communication in accordance with the IEEE 802.11be standard. Specific examples of the communication device 103 include, but are not limited to, a camera, a tablet, a smartphone, a PC, a mobile phone, and a video camera. The communication device 103 may also be any communication device capable of performing multi-link communication with other communication devices. The communication device 103 may also be an information processing device, such as a wireless chip, capable of performing wireless communication in accordance with the IEEE 802.11be standard. The network in FIG. 1 is a network configured with one AP and one STA, but the number of APs and STAs is not limited to this. The information processing device, such as a wireless chip, has an antenna for transmitting the generated signal.

[0023] 2 shows the hardware configuration of the communication devices 102 and 103 according to this embodiment. The communication devices 102 and 103 each include 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.

[0024] The storage unit 201 is configured with 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 stands for Read Only Memory, and RAM stands for Random Access Memory. In addition to memories such as ROM and RAM, the storage unit 201 may also use storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs. Furthermore, the storage unit 201 may include multiple memories.

[0025] The control unit 202 is configured with one or more processors such as a CPU or MPU, and controls the entire communication device 102 by executing a computer program stored in the storage unit 201. The control unit 202 may control the entire communication device 102 in cooperation with the computer program stored in the storage unit 201 and an OS (Operating System). The control unit 202 also generates data and signals (radio frames) to be transmitted in communication with other communication devices. The CPU stands for Central Processing Unit, and the MPU stands for Micro Processing Unit. The control unit 202 may also be equipped with multiple processors such as multi-core processors, and the entire communication device 102 may be controlled by the multiple processors.

[0026] Furthermore, the control unit 202 controls the function unit 203 to perform predetermined processes such as wireless communication, imaging, printing, projection, etc. The function unit 203 is hardware that enables the communication device 102 to perform predetermined processes.

[0027] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user via a monitor screen or a speaker. Here, the output from the output unit 205 may be a display on a monitor screen, an audio output from a speaker, a vibration output, or the like. 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 be integrated with the communication device 102 or may be separate units.

[0028] The communication unit 206 controls wireless communications compliant with the IEEE 802.11be standard. The communication unit 206 may also control wireless communications compliant with other IEEE 802.11 series standards 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. If the communication device 102 supports standards such as the NFC standard and Bluetooth in addition to the IEEE 802.11be standard, the communication unit 206 may control wireless communications compliant with these communication standards. If the communication device 102 can perform wireless communications compliant with multiple communication standards, the communication unit 206 may be configured with separate communication units and antennas compatible with each communication standard. The communication device 102 communicates data such as image data, document data, and video data with the communication device 103 via the communication unit 206. The antenna 207 may be configured separately from the communication unit 206, or may be configured together with the communication unit 206 as a single module.

[0029] The antenna 207 is an antenna capable of communication in the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. In this embodiment, the communication device 102 has one antenna, but it may have a different antenna for each frequency band. Furthermore, if the communication device 102 has multiple antennas, it may have a communication unit 206 corresponding to each antenna.

[0030] 3 shows the functional configuration of the communication devices 102 and 103 in this embodiment. The communication devices 102 and 103 are made up of a link connection unit 301, an encryption key management unit 302, a MAC frame generation unit 303, and a data transmission / reception unit 304.

[0031] The link connection unit 301 is a block that performs connection processing to establish one or more links used for data communication between the communication device 102 and the communication device 103. Specifically, the connection processing is composed of authentication processing, association processing, and 4-Way Handshake processing (4WHS processing). By executing the 4WHS processing, the PTK, which is an encryption key for unicast communication, and the GTK, which is an encryption key for broadcast / multicast communication, are shared between the communication device 102 and the communication device 103. Here, PTK stands for Pairwise Transient Key, and GTK stands for Group Transient Key. When connecting with the communication device 103, the communication device 102 may connect multiple links in advance, or may connect another link later while communicating via a specific link.

[0032] The encryption key management unit 302 is a block that manages the encryption keys for each link acquired by the link connection unit 301. In this embodiment, the encryption key management unit 302 manages the PTK, which is an encryption key for encrypting unicast communications, and the GTK, which is an encryption key for encrypting broadcast communications and multicast communications.

[0033] The MAC frame generation unit 303 is a block that generates MAC frames included in various management frames such as an Authentication Request and an Association Request, and data frames.

[0034] The data transmitter / receiver 304 transmits wireless frames including the MAC frames generated by the MAC frame generator 303 and receives wireless frames from the other device.

[0035] 4 shows a sequence diagram when communication device 102 and communication device 103 perform multi-link connection processing. In this embodiment, an example is shown in which two links are used. For example, in link 1, communication is performed via channel 1 in the 2.4 GHz band in the first frequency channel, and in link 2, communication is performed via channel 36 in the 5 GHz band in the second frequency channel.

[0036] In this embodiment, an example will be shown in which the encryption key set in link 1 is set as the encryption key for link 2.

[0037] First, in S401, the communication device 102 and the communication device 103 perform authentication processing for link 1 on the first frequency channel. The communication device 103 transmits an Authentication Request frame to request authentication, and in response, the communication device 102 transmits an Authentication Response frame. Note that in S401, if the SAE method is used as the authentication method, the Authentication Request frame and the Authentication Response frame are exchanged multiple times. Here, SAE stands for Simultaneous Authentication of Equals.

[0038] In S402, the communication device 102 and the communication device 103 perform association processing for link 1. The communication device 103 transmits an Association Request frame for connection, and in response to this, the communication device 102 transmits an Association Response frame.

[0039] In S403, the communication device 102 and the communication device 103 execute 4WHS processing to generate an encryption key to be used for communication on link 1. First, a PMK to be used for encrypting communication between the communication device 102 and the communication device 103 is generated and notified to the communication device 102 by the authentication server. The PMK is used to generate a PTK in 4WHS. Next, the communication device 102 exchanges random numbers called Anonce and Snonce with the communication device 103 in 4WHS Messages 1 and 2, and generates a PTK based on the PMK and these random numbers. The PTK consists of three parts: a Key Encryption Key (KEK), a Key Confirmation Key (KCK), and a Temporary Key (TK). The TK is used to encrypt unicast communication, and the KCK is used to encrypt broadcast or multicast communication. In 4WHS Message 3, the communication device 102 transmits the generated GTK, and the GTK is shared between the communication devices 102 and 103. As a result of S403, the communication device 102 sets the generated PTK, which is the encryption key to be used for unicast communication, in the wireless chip in S404 as the PTK for link 1. Similarly, the communication device 103 sets the PTK for link 1 in the wireless chip in S405.

[0040] Next, after the first link is established and a connection is established with link 1, connection processing for link 2 is performed. The connection processing for link 2 may be performed immediately after the connection processing for link 1, or may be performed after a predetermined time has elapsed. The processing of S411, S412, and S413 is the same as the processing of S401, S402, and S403. Because the PTK is generated using a random number, a PTK different from the PTK obtained in the processing of S403 is obtained. However, if a connected link exists, the PTK obtained in S413 is not used, and the PTK set for link 1 is set as the PTK for link 2 (S414). The communication device 103 similarly sets the PTK for link 1 as the PTK for link 2 (S415). In this way, a common PTK can be used between links when performing a multi-link connection. Note that the common encryption key includes a duplicated one.

[0041] FIG. 5 is a flowchart showing the flow of processing when the control unit 202 executes a program stored in the storage unit 201 of the communication device 102 to determine the PTK to be set for the link.

[0042] The communication device 102 may start the multilink communication in response to power-on of the communication device 102. Alternatively, the communication device 102 may start the multilink communication in response to an instruction to start the multilink communication from a user or an application. Alternatively, the communication device 102 may start the multilink communication in response to the amount of data to be communicated with the other device reaching or exceeding a predetermined threshold.

[0043] In S501, the communication device 102 receives an Authentication Request frame from the communication device 103 over link 1 and acquires information for identifying the communication device. This identification information is used to determine whether a link has already been established with the communication device 103. Examples of such information include, but are not limited to, an MLD ID (Multi-Link Device ID). Next, in S502, the communication device 102 transmits an Authentication Response frame to the communication device 103 in response to the Authentication Request frame received in S501, and executes authentication processing. Once the authentication processing is complete, in S503, the communication device 102 receives an Association Request frame from the communication device 103 and executes processing for transmitting an Association Response frame to the communication device 103. Once the association processing is complete, in S504, the communication device 102 executes 4WHS processing with the communication device 103 to generate a PTK, which is an encryption key. Next, in S505, it is determined whether the communication device that has established a connection over link 1 and the communication device that has established a connection over link 2 are the same communication device. Since there is no communication device that has previously established a connection with link 1, in S506 the PTK acquired with link 1 is set in the wireless chip as the PTK for that link. This completes the connection processing for link 1.

[0044] Next, in S501, the communication device 102 receives an Authentication Request frame from the communication device 103 on link 2 and acquires information identifying the communication device. This identification information is used to determine whether a link has already been established with the communication device 103. Next, in S502, in response to the Authentication Request frame received in S501, the communication device 102 transmits an Authentication Response frame to the communication device 103 and executes authentication processing. Once the authentication processing is complete, in S503, the communication device 102 receives an Association Request frame from the communication device 103 and executes processing to transmit an Association Response frame to the communication device 103. Once the association processing is complete, in S504, the communication device 102 executes 4WHS processing with the communication device 103 and generates a PTK, which is an encryption key. Next, in S505, it is determined whether the communication device that has established a connection on link 1 and the communication device that has established a connection on link 2 are the same communication device. More specifically, it is determined whether the identification information of the communication device included in the Authentication Request frame of S501 matches the identification information of the communication device that established the connection on link 1. If it is determined in S505 that they are the same communications device, the PTK set in link 1 is set as the PTK for that link (S507). In S507, the PTK generated in the 4WHS processing for link 2 is not used, and the PTK for link 1 is set in the wireless chip as the PTK for link 2. If it is determined in S505 that they are not the same communications device, the PTK generated in the 4WHS processing for link 2 is set in the wireless chip as the PTK for link 2 (S506). In S506, the PTK generated in the 4WHS processing for link 2 is set in the encryption key management unit 302 as the PTK for the connecting link. This completes the connection processing for link 2.

[0045] FIG. 6 shows a flowchart of the processing flow when the control unit 202 executes a program stored in the storage unit 201 of the communication device 103 to determine the PTK to be set for the link.

[0046] The communication device 103 starts the communication when it is powered on. Alternatively, the communication device 103 may start the communication when it receives an instruction to start multilink communication from a user or an application. Alternatively, the communication device 103 may start the communication when the amount of data to be communicated with the other device reaches or exceeds a predetermined threshold.

[0047] First, in S601, the communication device 103 stores the identification information of the communication device 102 in an Authentication Request frame on link 1. This information is used to determine whether a link has already been established with the communication device 102. The identification information of the communication device 102 is acquired when the user selects the destination communication device 102 on the UI of the communication device 103 and initiates a connection, or when the communication device 103 scans, finds the destination communication device 102, and automatically initiates a connection. Next, in S602, the communication device 103 transmits the Authentication Request frame set in S601 and executes a process to receive an Authentication Response frame from the communication device 102. Once the authentication process is complete, in S603, the communication device 103 transmits an Association Request frame and executes a process to receive an Association Response frame from the communication device 102. Once the association process is complete, in S604, the communication device 103 executes 4WHS processing with the communication device 102 to generate a PTK, which is an encryption key. Next, in S605, it is determined whether the communication device that has established a connection on link 1 and the communication device that has established a connection on link 2 are the same communication device. Since there is no communication device that has previously established a connection with link 1, in S606 the PTK acquired with link 1 is set in the wireless chip as the PTK for that link. This completes the connection processing for link 1.

[0048] Next, in S601, information for identifying the communication device 102 is stored in an Authentication Request frame on link 2. This is used to determine whether a link has already been established with the communication device 102. Next, in S602, the Authentication Request frame set in S601 is transmitted, and a process for receiving an Authentication Response frame from the communication device 102 is executed. Once the authentication process is complete, in S603, an Association Request frame is transmitted, and a process for receiving an Association Response frame from the communication device 102 is executed. Once the Association process is complete, in S604, 4WHS processing is executed with the communication device 102 to generate a PTK, which is an encryption key. Next, in S605, it is determined whether the communication device that has established a connection on link 1 and the communication device that has established a connection on link 2 are the same communication device. More specifically, it is determined whether the identification information of the communication device 102 set in the Authentication Request frame on S601 matches the identification information of the communication device 102 that has established a connection on link 2. If it is determined in S605 that they are the same communication device, the PTK set in link 1 is set as the PTK for that link (S607). If it is determined in S605 that they are not the same communication device, the PTK generated in the 4WHS processing for link 2 is set in the wireless chip as the PTK for link 2 (S606). In S606, the PTK generated in the 4WHS processing for link 2 is set in the encryption key management unit 302 as the PTK for that link.

[0049] In the present embodiment, the identification information of the communication device is stored in the Authentication Request frame, but it may also be stored in, for example, an Association Request frame.

[0050] According to this embodiment, when it is determined that the same communication device has established a connection on link 1 and link 2, it becomes possible to apply a common PTK between the links by setting the encryption key set on link 1 as the encryption key for link 2. Furthermore, applying a common PTK between the links makes it possible to communicate without discarding normal data frames.

[0051] Second Embodiment 7 shows a sequence diagram when communication device 102 and communication device 103 perform multi-link connection processing. In this embodiment, an example is shown in which two links are used. For example, in link 1, communication is performed via channel 1 in the 2.4 GHz band in the first frequency channel, and in link 2, communication is performed via channel 36 in the 5 GHz band in the second frequency channel.

[0052] In this embodiment, a method is shown in which the PTK set in link 2 is also set in link 1, and a common PTK is applied between the links.

[0053] The link 1 connection process from S701 to S713 is the same as the process from S401 to S413 in Figure 4, and therefore will not be described further. As a result of the process at S713, a PTK different from the PTK obtained in the process at S703 is obtained, but the communication device 102 sets this PTK as the PTK for link 2 in S714, and resets the PTK for link 2 as the PTK for link 1 in S716. The communication device 103 similarly sets the PTK for link 2 in S715, and resets the PTK for link 2 as the PTK for link 1 in S717. In this way, a common PTK can be used between links when performing a multi-link connection. Note that the common encryption key includes a duplicated one.

[0054] 8 shows a flowchart of the processing flow when the control unit 202 executes a program stored in the storage unit 201 of the communication device 102 to determine the PTK to be set in the link. The flow from S801 to S804 is the same as the processing from S501 to S504 in FIG. 5, and therefore will not be repeated.

[0055] In link 1, the communication device 102 receives an Authentication Request frame from the communication device 103 and acquires information identifying the communication device (S801). This identification information is used to determine whether a link has already been established with the communication device 103. Examples of the identification information include, but are not limited to, an MLD ID (Multi-Link Device ID). Next, in S802, in response to the Authentication Request frame received in S801, the communication device 102 transmits an Authentication Response frame to the communication device 103 and executes authentication processing. Once the authentication processing is complete, in S803, the communication device 102 receives an Association Request frame from the communication device 103 and executes processing to transmit an Association Response frame to the communication device 103. Once the association processing is complete, in S804, the communication device 102 executes 4WHS processing with the communication device 103 and generates a PTK, which is an encryption key. Next, in S805, it is determined whether the communication device that has established a connection in link 1 and the communication device that has established a connection in link 2 are the same communication device. Since there is no communication device that has previously established a connection in link 1, in S809 the PTK set in link 1 is set in the wireless chip as the PTK for that link. This completes the connection processing for link 1.

[0056] Next, in S801, the communication device 102 receives an Authentication Request frame from the communication device 103 on link 2 and acquires information identifying the communication device. S801-S804 on link 2 are as described above. In S805, it is determined whether the communication device that has established a connection on link 1 and the communication device that has established a connection on link 2 are the same communication device. More specifically, it is determined whether the identification information of the communication device set in the Authentication Request frame of S801 matches the identification information of the communication device that established a connection on link 1. If it is determined in S805 that they are the same communication device, it is determined in S806 whether data communication is currently being performed on link 1. If it is determined in S806 that link 1 is in progress, the PTK of the link in which data communication is being performed is not updated, and the PTK of link 1 is set in the wireless chip as the PTK of that link. This is because updating the PTK on a link in which data communication is being performed would cause the data communication to be interrupted midway. If it is determined in S806 that link 1 is not communicating, then in S808 the PTK generated in the 4WHS processing of link 2 is set in the wireless chip as the PTK for link 1. Furthermore, in S809 the PTK generated in the 4WHS processing of link 2 is set in the wireless chip as the PTK for link 2. If it is determined in S805 that they are not the same communication device, then in S809 the PTK generated in the 4WHS processing of link 2 is set in the wireless chip as the PTK for link 2.

[0057] In the present embodiment, the identification information of the communication device is stored in the Authentication Request frame, but it may be stored in another frame, for example, in the Association Request frame.

[0058] FIG. 9 is a flowchart showing the flow of processing when the control unit 202 executes a program stored in the storage unit 201 of the communication device 103 to determine the PTK to be set in the link.

[0059] The flow from S901 to S904 in link 1 is the same as the processing from S601 to S604 in FIG. 6, and therefore will be omitted.

[0060] First, in S901, the communication device 103 stores the identification information of the communication device 102 in an Authentication Request frame on link 1. This information is used to determine whether a link has already been established with the communication device 102. The identification information of the communication device 102 is acquired when the user selects the destination communication device 102 on the UI of the communication device 103 and starts the connection process, or when the communication device 103 scans, finds the destination communication device 102, and automatically starts the connection process. Next, in S902, the communication device 103 transmits the Authentication Request frame set in S901 and executes processing to receive an Authentication Response frame from the communication device 102. Once the authentication process is complete, in S903, the communication device 103 transmits an Association Request frame and executes processing to receive an Association Response frame from the communication device 102. Once the association process is complete, in S904, the communication device 103 executes 4WHS processing with the communication device 102 to generate a PTK, which is an encryption key. Next, in S905, it is determined whether the communication device that has established a connection on link 1 and the communication device that has established a connection on link 2 are the same communication device. Since there is no communication device that has previously established a connection in link 1, in S909 the PTK acquired in link 1 is set in the wireless chip as the PTK for that link. This completes the connection processing for link 1.

[0061] Next, in S901, the communication device 103 stores the identification information of the communication device 102 in an Authentication Request frame in link 2. The processing in S902 to S904 in link 2 is the same as the processing in S902 to S904 in link 1 of this embodiment, and therefore will be omitted.

[0062] In S905, it is determined whether the communication device that has established a connection on link 2 via link 1 is the same communication device as the communication device that has established a connection on link 2. More specifically, it is determined whether the identification information of the communication device 102 set in the Authentication Request frame in S901 matches the identification information of the communication device that established a connection on link 2. If it is determined in S905 that they are the same communication device, it is determined in S906 whether data communication is currently in progress on link 1. If it is determined in S906 that link 1 is in communication, the PTK of the link currently performing data communication is not updated in S907, and the PTK of link 2 is set in the wireless chip as the PTK of that link. This is because updating the PTK on a link currently performing data communication would cause the data communication to be interrupted. If it is determined in S906 that link 1 is not currently performing communication, the PTK generated in the 4WHS processing for link 2 is set in the wireless chip as the PTK of link 1 in S908. Furthermore, in S909, the PTK generated in the 4WHS processing of link 2 is set in the wireless chip as the PTK of link 2. If it is determined in S905 that the communication devices are not the same, the PTK generated in the 4WHS processing of link 2 is set in the wireless chip as the PTK of link 2 in S909.

[0063] In the present embodiment, the identification information of the communication device is stored in the Authentication Request frame, but it may be stored in another frame, for example, in the Association Request frame.

[0064] According to this embodiment, when it is determined that the same communication device has established a connection on link 1 and link 2, an encryption key generated on link 2 is set as the encryption key for link 1, thereby making it possible to apply a common PTK between the links. Furthermore, when link 1 is in communication, in order to prevent communication from being interrupted, the encryption key for link 1 is set as the encryption key for link 2, making it possible to apply a common PTK between the links. Furthermore, applying a common PTK between the links makes it possible to communicate without discarding normal data frames.

[0065] In this embodiment, the GTK is shared in addition to the PTK by performing 4WHS processing, but since a different GTK must be used for each link, 4WHS processing is always performed when establishing a new connection for each link.

[0066] It is also possible to provide a system or device with a recording medium storing software program code for implementing the above-described functions, and have the computer (CPU, MPU) of the system or device read and execute the program code stored in the recording medium. In this case, the program code itself read from the recording medium will implement the functions of the above-described embodiments, and the recording medium storing the program code will constitute the above-described device.

[0067] Examples of storage media that can be used to supply the program code include flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, ROMs, and DVDs.

[0068] In addition, the above-mentioned functions may be realized not only by the computer executing the read program code, but also by the operating system (OS) running on the computer performing some or all of the actual processing based on the instructions of the program code. OS is an abbreviation for Operating System.

[0069] Furthermore, the program code read from the storage medium may be written to a memory provided on a function expansion board inserted into a computer or a function expansion unit connected to the computer, and a CPU provided on the function expansion board or function expansion unit may then perform some or all of the actual processing based on the instructions of the program code to realize the above-mentioned functions.

[0070] 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. [Explanation of symbols]

[0071] 201 Storage section 202 Control section 203 Functional Department 204 Input section 205 Output section 206 Communications Department 207 Antenna

Claims

1. a connection control means for controlling a connection with another communication device; a first communication means for performing communication over a first frequency channel; second communication means for performing communication over a second frequency channel; management means for managing a Pairwise Transient Key (PTK) used to encrypt data transmitted by the first communication means and data transmitted by the second communication means; the connection control means, while establishing a connection with another communication device via the first frequency channel, newly establishes a connection with another communication device via the second frequency channel; the management means manages a first PTK generated based on communication via the first frequency channel so that the first PTK is used in common for encrypting data transmitted by the first communication means and encrypting data transmitted by the second communication means when the other communication device that has established a connection via the first frequency channel and the other communication device that has newly established a connection are the same communication device; If the other communication device that has established a connection via the first frequency channel and the other communication device that has newly established a connection are different communication devices, the first PTK generated based on the communication via the first frequency channel and the second PTK generated based on the communication via the second frequency channel are managed so that different PTKs are used for encrypting data transmitted by the first communication means and for encrypting data transmitted by the second communication means. A communication device comprising:

2. The communication system further includes a frame generating means for generating a MAC frame for communication by the first communication means and a MAC frame for communication by the second communication means.

2. The communication device according to claim 1.

3. The generating means generates a MAC frame including the first data portion and a MAC frame including the second data portion so that the first data portion and the second data portion of one piece of data are transmitted via different communication means.

3. The communication device according to claim 2.

4. A MAC frame including the data to be transmitted by the first communication means and a MAC frame including the data to be transmitted by the second communication means are generated so that the first communication means and the second communication means transmit the same data, respectively.

3. The communication device according to claim 2.

5. the communication device further comprises a plurality of antennas; The first communication means performs communication over the first frequency channel using the antenna.

5. The communication device according to claim 1, wherein the first and second inputs are connected to the first and second inputs.

6. The first frequency channel is a frequency channel in the 2.4 GHz band, and the second frequency channel is a frequency channel in the 5 GHz band.

6. The communication device according to claim 1, wherein the first and second inputs are connected to the first and second inputs.

7. the communication device has a first antenna used for communication in the 2.4 GHz band and a second antenna used for communication in the 5 GHz band, The first communication means performs communication over the first frequency channel using the first antenna.

7. The communication device according to claim 6.

8. the communication device has a first antenna used for communication in the 2.4 GHz band and the 5 GHz band, The first communication means performs communication over the first frequency channel using the first antenna.

7. The communication device according to claim 6.

9. The management means generates the first PTK based on a 4-Way Handshake (4WHS) performed via the first communication means.

9. The communication device according to claim 1, wherein the first and second inputs are connected to the first and second inputs.

10. The management means generates the second PTK based on the 4WHS performed via the second communication means.

10. The communication device according to claim 1, wherein the first and second communication terminals are connected to each other.

11. The communication device shares an Anonce and an Snonce with other communication devices by performing 4WHS, and the management means generates a PTK based on the Anonce and the Snonce.

11. The communication device according to claim 1, wherein the first and second communication terminals are connected to each other.

12. The PTK includes a KEK (Key Encryption Key), a KCK (Key Confirmation Key), and a TK (Temporary Key).

12. The communication device according to claim 1, wherein the first and second communication units are connected to each other.

13. Only the first communication means that communicates via the first frequency channel transmits a management frame.

13. The communication device according to claim 1, wherein the first and second communication terminals are connected to each other.

14. The management frame is one of a beacon frame, a probe request frame, a probe response frame, an association request frame, and an association response frame.

14. The communication device according to claim 13.

15. a connection control step of controlling a connection with another communication device; a first communication step of performing communication over a first frequency channel; a second communication step of performing communication over a second frequency channel; a management step of managing a Pairwise Transient Key (PTK) used to encrypt data to be transmitted in the first communication step and data to be transmitted in the second communication step, the connection control step includes, while a connection with another communication device is established via the first frequency channel, newly establishing a connection with another communication device via the second frequency channel; In the management step, when the other communication device that has established a connection via the first frequency channel and the other communication device that has newly established a connection are the same communication device, the first PTK generated based on the communication via the first frequency channel is managed so that the first PTK is used in common for encrypting data to be transmitted in the first communication step and encrypting data to be transmitted in the second communication step; If the other communication device that has established a connection via the first frequency channel and the other communication device that has newly established a connection are different communication devices, the first PTK generated based on the communication via the first frequency channel and the second PTK generated based on the communication via the second frequency channel are managed so that different PTKs are used for encrypting data to be transmitted in the first communication step and for encrypting data to be transmitted in the second communication step. A method for controlling a communication device.

16. A program for causing a computer to function as the communication device control method according to claim 15.

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