Communication device, communication method, and program

Abstract

To prevent receiving frames transmitted in all of a plurality of frequency channels in an overlapping manner when a communication device and the other communication device establish a connection through the frequency channels.SOLUTION: A communication device receives, while the communication device establishes a connection with the other communication device through a first frequency channel and a second frequency channel, a second frame that stores information indicating whether first frames transmitted to the other communication device through the first frequency channel and the second frequency channel are transmitted in an overlapping manner through the first frequency channel and the second frequency channel, and when receiving the second frame through the first frequency channel, controls not to receive the second frame through the second frequency channel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication device that performs wireless communication. [Background technology]

[0002] The IEEE802.11 series is known as a WLAN communication standard formulated by the IEEE (Institute of Electrical and Electronics Engineers). WLAN is an abbreviation for Wireless Local Area Network. The IEEE802.11 series standards include the IEEE802.11a / b / g / n / ac / ax standards. Patent Document 1 discloses that the IEEE802.11ax standard performs wireless communication using Orthogonal Frequency Division Multiple Access (OFDMA).

[0003] In order to further improve throughput and frequency utilization efficiency, the IEEE is considering formulating the IEEE802.11be standard (hereinafter referred to as 11be) as a new standard in the IEEE802.11 series.

[0004] Conventionally, IEEE802.11 APs (Access Points) establish connections with STAs (Station) via a single frequency channel for communication. In 11be, the introduction of Multi-Link communication is being considered, in which one AP establishes connections with STAs (Station) via multiple frequency channels for communication. [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] When one AP and one STA establish a first link and a second link and are performing Multi-Link communication, if the AP transmits a frame via multicast or broadcast communication, the same frame will be transmitted to the same STA multiple times. However, the STA receiving the frame on the first frequency channel cannot determine whether the frame will also be transmitted by the AP on the second frequency channel, and there is a risk of receiving the same frame multiple times unnecessarily.

[0007] In view of the above problems, the present invention aims to prevent duplicate reception of frames transmitted on all frequency channels when a communication device and another communication device establish a connection via multiple frequency channels. [Means for solving the problem]

[0008] In order to achieve the above object, a communication device of the present invention includes an establishing means for establishing a first link using a first frequency channel and a second link using a second frequency channel with another communication device; a first receiving means for receiving a first frame including predetermined information transmitted to the other communication device via the first link while the first link and the second link are established with the other communication device by the establishing means; a second receiving means for receiving a second frame including predetermined information transmitted to the other communication device via the second link while the first link and the second link are established between the other communication device and the second communication device by the establishing means; When the first link and the second link are established between the other communication device and the other communication device by the establishing means, 3 The first frame to be received 3 a receiving means for receiving the first frame received by the first receiving means via the first link; Contains The predetermined information and the predetermined information included in the second frame received by the second receiving means via the second link matches. Based on In the first link and the second link The above-mentioned duplicated transmissions 3 Frame The third receiving means and a control means for controlling the reception process not to be performed.

[0009] The communication device of the present invention Communication method teeth, The first frequency channel The first link used The second frequency channel The second link used Other communication devices Between Establish Establish process and, said establishment process By the first link and the second Links and of before With other communication devices Between In the established state, the first link to the other communication device via Contains the specified information First frame a first receiving step of receiving , a second receiving step of receiving a second frame transmitted from the other communication device via the second link while the first link and the second link are established with the other communication device; a control step of controlling, based on the predetermined information of the first frame received in the first receiving step via the first link, so that the second receiving step does not perform a receiving process of the second frame that is transmitted in duplicate; , It has. [Effects of the Invention]

[0010] According to the present invention, when a communication device and another communication device establish a connection via multiple frequency channels, it is possible to prevent duplicate reception of frames transmitted on all frequency channels. [Brief explanation of the drawings]

[0011] [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. 2 is a diagram showing an example of a TIM element frame in this embodiment. [Figure 5] FIG. 10 is a sequence diagram showing a process in which the communication device 103 receives DTIM Beacon frames at the same timing over multiple links. [Figure 6]FIG. 10 is a sequence diagram showing a process in which the communication device 103 receives DTIM Beacon frames at different timings on multiple links. [Figure 7] 10 is a flowchart showing a process executed by the communication device 102 when transmitting a Beacon frame. [Figure 8] 10 is a flowchart showing a process executed when a communication device 102 in this embodiment transmits a DTIM Beacon frame. [Figure 9] 10 is a flowchart showing a process executed by the communication device 103 in this embodiment when receiving a DTIM Beacon frame. [Figure 10] FIG. 10 is a diagram showing the configuration of a network constructed by a communication device 102 in a second embodiment. [Figure 11] 10 is a flowchart showing a process executed when the communication device 102 in this embodiment transmits a DTIM Beacon frame. [Figure 12] 10 is a flowchart showing a process executed by the communication device 103 in this embodiment when receiving a DTIM Beacon frame. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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.

[0013] An example of the configuration of a network according to this embodiment is shown in Fig. 1. Fig. 1 shows a configuration including one AP (communication device 102) and one STA (communication device 103) as communication devices.

[0014] An AP (Access Point) 102 is a communication device that serves to construct a network 101. The network 101 is a wireless network.

[0015] Furthermore, STAs (Station) 103 are communication devices that participate in the network 101. Each communication device is compatible with the IEEE 802.11be (EHT) standard and can perform wireless communication compliant with the IEEE 802.11be standard via the network 101. IEEE stands for Institute of Electrical and Electronics Engineers. EHT stands for Extremely High Throughput. 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. Each communication device can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0016] Furthermore, the communication device 102 and the communication device 103 establish links via multiple frequency channels and perform multi-link communication. An AP that performs multi-link communication is also called an AP MLD (Multi-Link Device). Here, the frequency channel refers to a frequency channel defined in the IEEE 802.11 series of standards and capable of performing wireless communication in accordance with the IEEE 802.11 series of standards. The IEEE 802.11 series of standards defines multiple frequency channels for each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands.

[0017] In addition, the IEEE 802.11 series of standards defines the bandwidth of each frequency channel as 20 MHz. By bonding adjacent frequency channels, a single frequency channel may utilize a bandwidth of 40 MHz or more. 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 the second link 105 via the second frequency channel in parallel with the first link 104 via the first frequency channel.

[0018] In this way, the communication device 102 can improve the throughput of communication with the communication device 103 by establishing a link with the communication device 103 via multiple frequency channels.

[0019] In multi-link communication, the communication device 102 and the communication device 103 may establish multiple links in different frequency bands. For example, the communication device 102 and the communication device 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. Links in the same frequency band and links in different frequency bands may be mixed. For example, the communication device 102 and the communication device 103 may establish a third link via channel 36 in the 5 GHz band, in addition to the first link 104 via channel 1 in the 2.4 GHz band and the second link 105 via channel 5 in the 2.4 GHz band. By establishing multiple connections with communication device 103 using different frequency bands, communication device 102 can communicate with communication device 103 using other bands even when one band is congested, thereby preventing a decrease in throughput in communication with communication device 103.

[0020] In multi-link communication, the multiple links established between the communication device 102 and the communication device 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 device 102 and the communication device 103 needs to be at least greater than 20 MHz. Note that in this embodiment, the communication device 102 and the communication device 103 establish a first link 104 and a second link 105, but three or more links may be established.

[0021] When performing multi-link communication, the communication device 102 constructs multiple wireless networks corresponding to the respective links. In this case, the communication device 102 has multiple APs internally and operates to construct a wireless network for each of them. The APs that the communication device 102 has internally may be one or more physical APs, or may be multiple virtual APs configured on one physical AP. When multiple links are established on frequency channels that belong to a common frequency band, the multiple links may use a common wireless network.

[0022] Although the communication device 102 and the communication device 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 is referred to as an IEEE 802.11 series standard. In addition to the IEEE 802.11 series standards, the communication device 102 and the communication device 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.

[0023] 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 multilink 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 multilink 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 configured with one AP and one STA, but the number of APs and STAs is not limited to this. For example, two or more STAs may participate in a network established by one AP, and multilink communication may be performed between the respective devices. The information processing device, such as a wireless chip, has an antenna for transmitting the generated signal.

[0024] In this embodiment, the communication device 102 is an AP and the communication device 103 is an STA, but this is not limiting, and both the communication device 102 and the communication device 103 may be STAs. In this case, the communication device 102 operates as an STA, but also operates as a device that has a role of constructing a wireless network for establishing a link with the communication device 103.

[0025] 2 shows an example of the hardware configuration of the communication device 102. The communication device 102 includes 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.

[0026] 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.

[0027] 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 a multi-core processor, and the entire communication device 102 may be controlled by the multiple processors.

[0028] 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.

[0029] 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.

[0030] The communication unit 206 controls wireless communication conforming to the IEEE 802.11be standard. The communication unit 206 may also control wireless communication conforming to other IEEE 802.11 series standards in addition to the IEEE 802.11be standard, or control wired communication such as a wired LAN. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communication generated by the control unit 202. The communication device 102 may have multiple communication units 206. When a communication device 102 having multiple communication units 206 establishes multiple links in multi-link communication, it establishes at least one link per communication unit 206.

[0031] Alternatively, the communication device 102 may establish multiple links using a single communication unit 206. In this case, the communication unit 206 performs communication via the multiple links by switching between frequency channels that operate in a time-division manner. If the communication device 102 supports standards such as the NFC standard and Bluetooth in addition to the IEEE 802.11be standard, it may control wireless communications in accordance with these standards. If the communication device 102 can perform wireless communications in accordance with multiple communication standards, it 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.

[0032] 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.

[0033] The communication device 103 has the same hardware configuration as the communication device 102 .

[0034] 3 shows an example of the functional configuration of the communication device 102. The communication device 102 includes a received frame analysis unit 301, a transmitted frame generation unit 302, and a frame transmission / reception unit 303. The communication device 102 further includes a Beacon frame management unit 304.

[0035] The received frame analysis unit 301 is a functional block that analyzes a frame received from an opposing communication device.

[0036] The transmission frame generation unit 302 is a functional block that generates a frame to be transmitted to the opposing communication device.

[0037] The frame transmission / reception unit 303 is a functional block that transmits and receives frames to and from the opposing communication device, and controls the transmission and reception of Beacon frames, group addressed frames, data frames, and the like within this functional block.

[0038] The Beacon frame management unit 304 is a functional block that instructs the generation and analysis of Beacon frames. This functional block instructs the transmission frame generation unit 302 to include information for determining whether a Group Addressed Frame is being transmitted twice in a Beacon frame. It also instructs the reception frame analysis unit 301 to analyze the information for determining whether a Group Addressed Frame is being transmitted twice in a Beacon frame.

[0039] The communication device 103 has the same functional configuration as the communication device 102 .

[0040] The TIM Element included in the Beacon frame is shown in Figure 4. This Element is defined in accordance with the IEEE 802.11 standard.

[0041] The Element ID field 401 stores "5", which indicates that the Element of the Beacon frame is a TIM Element.

[0042] The Length field 402 indicates the length of the TIM Element.

[0043] The DTIM Count field 403 indicates whether the Beacon frame containing the Element is a DTIM (Delivery Traffic Indication Map) Beacon frame. When the DTIM count indicated in this field is "0", the Beacon frame containing the Element is a DTIM Beacon frame, and there is a possibility that a Group Addressed Frame will be transmitted after the DTIM Beacon frame. If the DTIM count value is any value other than "0", it is not a DTIM Beacon frame, and therefore not a Group Addressed Frame.

[0044] The DTIM Period field 404 indicates the DTIM interval. For example, if the DTIM interval is set to "3," this indicates that one of the three Beacon frames transmitted will be a DTIM Beacon frame. The DTIM count is decremented each time a Beacon frame is transmitted, so the DTIM count is set to "0" when a DTIM Beacon frame is transmitted, and the DTIM count for the next Beacon frame transmitted is set to an initial value (=maximum value). Here, for example, if the DTIM interval is set to "3," the maximum value of the DTIM count is "2," so the initial value is set to "2."

[0045] The Bitmap Control field 405 indicates whether or not there is a Group Addressed Frame by its bit.

[0046] The following is a sequence diagram when the Bitmap Control field 405 is set to "1" and the DTIM count is set to "0." When the Bitmap Control field 405 is set to "1" and the DTIM count is set to "0," a Group Addressed Frame is transmitted after the DTIM Beacon frame is transmitted.

[0047] Here, a Group Addressed Frame refers to a frame that includes a MAC address in the Destination Address (DA) of the MAC frame, where the Group Bit is set to 1. Multicast frames also have the Group Bit set to 1, so they are also Group Addressed Frames.

[0048] Furthermore, in FIG. 5, the DTIM Beacon frames are transmitted at the same timing in Link 104 and Link 105, but may be transmitted at different timings in Link 104 and Link 105 as in FIG.

[0049] (Embodiment 1) 7 is a flowchart showing the flow of processing performed by the control unit 202 executing a program stored in the storage unit 201 of the communication device 102. This flowchart shows an example of processing performed when the communication device 102 in this embodiment transmits a Beacon frame.

[0050] The process of this flowchart starts when the communication device 102 is powered on. Alternatively, the process may start when the user completes operational settings for the communication device 102 related to Beacon frames.

[0051] The communication device 102 determines whether the value stored in the DTIM Count field 403 of the TIM element included in the Beacon frame to be transmitted is "0" (S701). If the value stored in the DTIM Count field 403 is not "0" (NO in S701), the communication device 102 transmits the Beacon frame (S702). After executing the process of S702, the value stored in the DTIM Count field 403 is decremented (S703), and the communication device 102 determines whether a stop instruction has been received (S706). Specifically, the communication device 102 determines whether a user has instructed the communication device 102 to stop operating as an AP. If a stop instruction has been received (YES in S706), the communication device 102 stops operating as an AP and ends the process of this flowchart. On the other hand, if a stop instruction has not been received (NO in S706), the communication device 102 performs the process of S701.

[0052] If the value stored in the DTIM Count field 403 is "0" (YES in S701), a DTIM Beacon frame transmission process is performed (S704). Details of the process of S704 will be described later with reference to FIG. 8. After performing the process of S704, the value of the DTIM Count field 403 is reset to its initial value (S705). Here, for example, if the DTIM interval is set to "3," the maximum value of the DTIM count is "2," so "2" is set as the initial value. After performing the process of S705, it is determined whether an instruction to stop the AP has been received (S706). If it is determined in S706 that an instruction to stop has not been received (NO in S706), the process of S701 is performed. On the other hand, if an instruction to stop has not been received (YES in S706), the communication device 102 stops operating as an AP and ends the process of this flowchart.

[0053] 8 is a flowchart showing the flow of processing performed by the control unit 202 executing a program stored in the storage unit 201 of the communication device 102. This flowchart shows an example of processing performed when the communication device 102 in this embodiment transmits a DTIM Beacon frame. The processing of this flowchart is initiated in response to an instruction to perform processing in S704.

[0054] The communication device 102 determines whether or not it holds a Group Addressed Frame to be transmitted (S801). If it is determined that the frame is not held (NO in S801), it transmits a Beacon frame (S804) and ends the processing of this flowchart.

[0055] If it is determined that the claim is held (YES in S801), the communication device 102 sets the Bitmap Control field 405 in the TIM Element of the Beacon frame to be transmitted to "1" and determines whether the device is currently performing multilink communication (S802). Setting the Bitmap Control field 405 to "1" indicates that a Group Addressed Frame will be transmitted after transmitting the DTIM Beacon frame. If it is determined in S802 that multilink communication is not currently being performed (NO in S802), the communication device 102 transmits a DTIM Beacon frame (S804) and terminates the processing of this flowchart.

[0056] If it is determined that multilink communication is being performed (YES in S802), information for determining duplication is stored in the Beacon frame (S803). The information for determining duplication is information indicating that the Group Addressed Frames transmitted by the communication device 102 via the link 104 and the link 105 are the same frame. The information for determining duplication is information represented by 1 bit, where "1" indicates that the Group Addressed Frame is transmitted duplicately, and "0" indicates that the Group Addressed Frame is not transmitted duplicately. The information for determining duplication may be stored in an Element marked as Reserved in the Beacon frame, but is not limited to this. Alternatively, the information for determining duplication may be stored in an Element in which "221", indicating vendor-specific information (Vendor Specific), is stored in the Element ID of the Beacon frame. Alternatively, a new field may be created in the TIM Element shown in FIG. 4, and the value of the Group Addressed Frame identifier may be stored in that field.

[0057] The communication device 102 transmits a DTIM Beacon frame that stores information for determining whether or not there is a duplication (S804), and ends the processing of this flow chart.

[0058] 9 is a flowchart showing the flow of processing performed by control unit 202 executing a program stored in storage unit 201 of communication device 103. This flowchart shows an example of processing performed when communication device 103 in this embodiment receives a DTIM Beacon frame. The processing of this flowchart is initiated when communication device 103 receives a DTIM Beacon frame.

[0059] The communication device 103 determines whether or not there is an instruction to receive a Group Addressed Frame (S901). Specifically, it determines whether or not the bit in the Bitmap Control field 405 of the received DTIM Beacon frame is "1." If it is determined that there is no instruction to receive (NO in S901), the processing of this flowchart ends.

[0060] If it is determined that a reception instruction has been issued (YES in S901), the communication device 103 determines whether or not the device itself is performing multilink communication (S902). If it is determined that multilink communication is not being performed (NO in S902), the communication device 102 receives a Group Addressed Frame transmitted after the DTIM Beacon frame (S904), and the processing of this flowchart ends.

[0061] If it is determined that multi-link communication is being performed (YES in S902), it is determined whether the Group Addressed Frames received via link 104 and link 105 overlap (S903). Specifically, information for determining overlap stored in the Beacon frame is checked. In this embodiment, if the bit stored in the Element ID is 1, this indicates that a duplicate Group Addressed Frame has been received. If it is determined in S903 that there is no overlap (NO in S903), the Group Addressed Frame transmitted after the DTIM Beacon frame is received (S904), and the processing of this flowchart ends.

[0062] On the other hand, if it is determined in S903 that there is a duplication (YES in S903), it is determined whether or not it is necessary to receive the Group Addressed Frame (S904). Specifically, this determination is made based on information on whether or not it is necessary to receive that is set in the storage unit 201 by the process in S905, which will be described later. Note that this information is a bit indicating whether or not it is necessary to receive the Group Addressed Frame; if the bit is set to "1", it indicates that it is not necessary to receive it, and if the bit is set to "0", it indicates that it is necessary to receive it.

[0063] If it is determined in S904 that reception is necessary (YES in S904), the reception process for the next Group Addressed Frame is set to unnecessary (S905). Specifically, the bit that indicates whether reception is necessary or not, which is stored in the storage unit 201, is set to "1." Having set the next reception process to unnecessary in S905, the communication device 103 receives the Group Addressed Frame (S907) and ends the processing of this flowchart.

[0064] On the other hand, if it is determined that reception is not necessary (YES in S904), the reception process for the next Group Addressed Frame is set to necessary (S906). Specifically, a bit stored in the storage unit 201 indicating whether reception is necessary or not is set to "0." The bit is set to "0" so that the Group Addressed Frame can be received when the next DTIM Beacon frame is received. Having set the next reception process to necessary in S906, the communication device 103 ends the processing of this flowchart without receiving the Group Addressed Frame.

[0065] According to this embodiment, the communication device 103 can determine that the same Group Addressed Frame is transmitted on the link 104 and the link 105. As a result, the same Group Addressed Frame is not received in duplicate, thereby reducing the load of the reception process.

[0066] 6, when a Group Addressed Frame is transmitted with a lag, if the communication device 103 is a communication device that cannot perform transmission processing on link 104 while receiving processing on link 105, the following advantage is obtained: By controlling so that the same Group Addressed Frame is not received twice, it becomes possible to perform data transmission processing on link 104 even during the period when the frame is being received on link 105 in FIG.

[0067] (Embodiment 2) In the first embodiment, an example was shown in which the STA controls reception based on information for determining duplication contained in the DTIM Beacon frame when the AP transmits the same Group Addressed Frame via link 104 and link 105. In the second embodiment, a process for determining duplication when different Group Addressed Frames are transmitted by the AP via link 104 and link 105 will be described.

[0068] FIG. 10 shows an example of the configuration of a network according to this embodiment.

[0069] 10 shows a case where, for example, link 104 and link 1003 operate in the 2.4 GHz band, and link 105 and link 1004 operate in the 5 GHz band. In this way, link 104 and link 105 have different multicast groups. Therefore, for example, when links 105 and 1004, which use the 5 GHz band, are transmitting channel switch announcements, it is conceivable that different frames will be transmitted on link 104 and link 1003.

[0070] 11 is a flowchart showing the flow of processing performed by the control unit 202 executing a program stored in the storage unit 201 of the communication device 102. This flowchart shows an example of processing performed when the communication device 102 in this embodiment transmits a DTIM Beacon frame. The processing of this flowchart is initiated in response to an instruction to perform processing in S704.

[0071] The processing in S1101 and S1102 is the same as the processing in S801 and S802 in FIG.

[0072] If it is determined that multi-link communication is not in operation (NO in S1102), a Beacon frame is transmitted (S1106), and the processing of this flowchart ends.

[0073] If it is determined that multi-link communication is in operation (YES in S1102), it is determined whether the retained Group Addressed Frame is the same as the Group Addressed Frame to be transmitted on another link (S1103). Specifically, it is determined whether the Group Addressed Frame to be transmitted on link 105 is the same as the Group Addressed Frame to be transmitted on link 104. It may also be determined that the frames are the same if only a portion of the Group Addressed Frame is the same. The portion of the Group Addressed Frame is, for example, the data portion of the Group Addressed Frame excluding the IEEE 802.11 header, physical header, and FCS (Frame Check Sequence).

[0074] If it is determined that they are not the same (NO in S1103), a Group Addressed Frame identifier different from that of the other link is stored in the DTIM Beacon frame (S1105). The Group Addressed Frame identifier is a value that indicates whether the Group Addressed Frame transmitted over link 104 is the same as the frame transmitted over link 105. The initial value of the Group Addressed Frame identifier is "0," but this value is not limited to this. The value of the Group Addressed Frame identifier is stored in storage unit 201, and this value is incremented and stored in the DTIM Beacon frame. In other words, a value different from the Group Addressed Frame identifier stored in the DTIM Beacon frame of the other link is stored in the Beacon frame. Specifically, the Group Addressed Frame identifier stored in the received DTIM Beacon frame is added by "1," and the value is stored in the DTIM Beacon frame. For example, if the identifier value stored in storage unit 201 is "5," it is increased to "6" and stored in the DTIM Beacon frame. The value to be incremented is not limited to "1," and any integer value other than "1" may be added.

[0075] Furthermore, a field for storing the Group Addressed Frame identifier is newly provided in a reserved element of the Beacon frame, and the Group Addressed Frame identifier is stored in the field. The communication device 102 transmits a DTIM Beacon frame in which an identifier value different from that of the other link in S1105 is stored (S1106), and ends the processing of this flowchart.

[0076] On the other hand, if it is determined that the received Group Addressed Frame is the same as the Group Addressed Frame that should be transmitted over another link (YES in S1103), the value of the Group Addressed Frame identifier stored in storage unit 201 is stored in the DTIM Beacon frame (S1104). In other words, the same value as the received Group Addressed Frame identifier is stored in the DTIM Beacon frame. After storing the Group Addressed Frame identifier in the Beacon frame in S1104, communication device 102 transmits the DTIM Beacon frame (S1106) and ends the processing of this flowchart.

[0077] 12 is a flowchart showing the flow of processing performed by control unit 202 executing a program stored in storage unit 201 of communication device 103. This shows an example of a flowchart executed when communication device 103 in this embodiment receives a DTIM Beacon frame. The processing of this flowchart is started when communication device 103 receives a DTIM Beacon frame.

[0078] The processing in S1201 and S1202 is the same as the processing in S901 and S902 in FIG.

[0079] If it is determined that multi-link communication is not in operation (NO in S1202), a Group Addressed Frame is received (S1206), and the processing of this flowchart ends.

[0080] If it is determined that multi-link communication is in operation (YES in S1202), it is determined whether or not a Group Addressed Frame identifier is stored in the received DTIM Beacon frame (S1203). Specifically, it is determined whether or not a Group Addressed Frame identifier is stored in a new Element field indicating that a Group Addressed Frame identifier is stored in the DTIM Beacon frame. If it is determined that a Group Addressed Frame identifier is not stored (NO in S1203), the Group Addressed Frame is received (S1206), and the processing of this flowchart ends.

[0081] If the received DTIM Beacon frame does not contain an Element ID corresponding to the new Element field, it may be determined that the identifier is not stored.

[0082] If it is determined that a Group Addressed Frame identifier is stored (YES in S1203), it is determined whether the saved Group Addressed Frame identifier and the identifier stored in the new Element field have the same value (S1204). Specifically, the value of the Group Addressed Frame identifier stored in storage unit 201 is compared with the value of the identifier stored in the new Element field of the currently received DTIM Beacon frame to determine whether they are the same value. If it is determined that the value is the same as the saved Group Addressed Frame identifier (YES in S1204), the processing of this flowchart ends. In other words, it is determined that the Group Addressed Frame to be received is a duplicate, and reception processing is not performed.

[0083] On the other hand, if it is determined that the value is not the same as the saved Group Addressed Frame identifier (NO in S1204), the value of the identifier stored in the new Element field of the currently received DTIM Beacon frame is stored in storage unit 201 (S1205). Having stored the value of the Group Addressed Frame identifier in S1205, communication device 103 receives the Group Addressed Frame (S1206) and ends the processing of this flowchart.

[0084] According to this embodiment, the communication device 103 can determine that the same Group Addressed Frame is transmitted on the link 104 and the link 105 .

[0085] The flowcharts of the communication device 102 and the communication device 103 shown in each embodiment are not limited to the network configuration of Fig. 1. For example, as shown in Fig. 12, they may be implemented in a network configuration including STA1201 and STA1202 that perform single-link communication via the same frequency channel as link 104 or link 105. Note that the processing of each embodiment may be executed when the communication devices are connected to links via the same frequency channel as link 104 and link 105. For example, in addition to the configuration of Fig. 1, the processing of each embodiment may be executed when STA1201 is connected to link 1203, which is the same frequency channel as link 104, and STA1202 is connected to link 1204, which is the same frequency channel as link 105.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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]

[0091] 201 Storage section 202 Control section 203 Functional Department 204 Input section 205 Output section 206 Communications Department 207 Antenna

Claims

1. A communication device, establishing means for establishing a first link using a first frequency channel and a second link using a second frequency channel with another communication device; a first receiving means for receiving a first frame including predetermined information transmitted to the other communication device via the first link while the first link and the second link are established between the other communication device and the first communication device by the establishing means; a second receiving means for receiving a second frame including predetermined information transmitted to the other communication device via the second link while the first link and the second link are established between the other communication device and the second communication device by the establishing means; a third receiving means for receiving a third frame transmitted from the other communication device via the second link while the first link and the second link are established between the other communication device and the third communication device by the establishing means; a control means for controlling the third receiving means not to perform a receiving process on the third frame transmitted in duplicate via the first link and the second link, based on a match between the predetermined information included in the first frame received by the first receiving means via the first link and the predetermined information included in the second frame received by the second receiving means via the second link; A communication device comprising:

2. 2. The communication device according to claim 1, wherein the third frame is a Group Addressed Frame conforming to the IEEE 802.11 series standard.

3. 3. The communication device according to claim 1, wherein the first frame and the second frame are beacon frames.

4. The communication device according to claim 3 , wherein the predetermined information is stored in a TIM element or a Vendor Specific element of the beacon frame.

5. 5. The communication device according to claim 1, wherein the communication device performs multi-link communication in accordance with the IEEE 802.11 series standard.

6. 6. The communication device according to claim 1, wherein the communication device is a communication device that cannot simultaneously transmit data on the second frequency channel while receiving data via the first frequency channel.

7. A communication method for a communication device, comprising: an establishing step of establishing a first link using a first frequency channel and a second link using a second frequency channel with another communication device; a first receiving step of receiving a first frame including predetermined information transmitted to the other communication device via the first link while the first link and the second link have been established with the other communication device by the establishing step; a second receiving step of receiving a second frame including predetermined information transmitted to the other communication device via the second link while the first link and the second link have been established between the other communication device and the other communication device by the establishing step; a third receiving step of receiving a third frame transmitted from the other communication device via the second link while the first link and the second link are established with the other communication device; a control step of controlling the third frame, which is transmitted in duplicate via the first link and the second link, so that the third frame is not subjected to reception processing in the third receiving step, based on a match between the predetermined information included in the first frame received in the first receiving step via the first link and the predetermined information included in the second frame received in the second receiving step via the second link; A communication method for a communication device, comprising:

8. A program for causing a computer to function as each of the means of the communication device according to any one of claims 1 to 6.

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