COMMUNICATION DEVICE, CONTROL METHOD FOR COMMUNICATION DEVICE, AND PROGRAM

Abstract

To properly manage links in multilink communication.SOLUTION: A communication device that conforms to the IEEE802.11 series standards and is capable of communicating over a plurality of links determines a first link, from among a plurality of links established with a communication partner device, to be a link for which transmission by the communication partner device is prohibited, and a transmission inhibition period on the first link, transmits a first frame containing information on prohibiting transmission on the first link through the first link, and transmits a second frame containing information on prohibiting transmission on the first link through a second link different from the first link from among the plurality of links before the transmission inhibition period begins.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multi-link communication technique. [Background technology]

[0002] The IEEE802.11 series is known as a wireless LAN (Local Area Network) communication standard established by the IEEE (Institute of Electrical and electronics Engineers). The IEEE802.11 series standards include IEEE802.11a / b / g / n / ac / ax standards. Patent Document 1 discloses that a link is established when an AP (Access Point) and a STA (Station) communicate with each other.

[0003] In order to further improve throughput and frequency utilization efficiency, IEEE is considering the formulation of the IEEE802.11be standard as a new standard in the IEEE802.11 series. The IEEE802.11be standard considers multi-link communication, in which one AP establishes multiple links with one Non-AP (Non-Access Point) STA (also simply called STA) via multiple different frequency channels to communicate. Such an AP is called an AP MLD (Access Point Multi-Link Device), and the STA is called a Non-AP MLD (Non-Access Point Multi-Link Device). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2012-523202 Summary of the Invention [Problem to be solved by the invention]

[0005] In the IEEE802.11 series of standards, an AP can transmit a Beacon frame or a Probe Response frame that includes a Quiet element that contains information such as the period during which a link is to be kept quiet (transmission by the communication partner device is prohibited). When a STA receives this frame, it remains in the quiet state for the period indicated by the Quiet element, i.e., the STA refrains from transmitting. During this period, the AP can perform radar wave observations and noise measurements for DFS (Dynamic Frequency Selection) without being affected by the STA's transmission signal.

[0006] However, in multi-link communication, even if an AP MLD transmits a frame containing a quiet element to make the link quiet, the Non-AP MLD may not be able to receive the quiet element. This is because the Non-AP MLD may put the link in a doze state to save power, or the signal transmitted on the link may be interfered with by a signal transmitted by the Non-AP MLD itself on another link. If the Non-AP MLD cannot receive the quiet element, it may transmit a signal on a link that should be quiet. In this case, the AP MLD may not be able to properly observe radar waves, measure noise, etc.

[0007] In view of the above, an object of the present invention is to perform appropriate link management in multi-link communication. [Means for solving the problem]

[0008] As one means for achieving the above object, the present invention In one embodiment Communication Equipment teeth, a determining means for determining a first link to be set as a link for which transmission is prohibited by the communication partner device, among a plurality of links established with the communication partner device, and a transmission prohibition period for the first link; ,before At the first link The above Prohibit sending Period Including the information1 a second link different from the first link among the plurality of links is transmitted before the transmission prohibition period begins. Send With a means of communication and The information on the transmission inhibition period is characterized in that it is expressed based on a TBTT (Target Beacon Transmission Time) of the second link. A communication device according to another aspect of the present invention includes: a determination means for determining a first link, among a plurality of links established with a communication partner device, as a link for which transmission is prohibited by the communication partner device, and a timing for determining a start of a transmission prohibition period on the first link; and a transmission means for transmitting, before the start of the transmission prohibition period, a first frame including information regarding the start of the transmission prohibition period on the first link and information indicating a change in a channel of the first link, through a second link among the plurality of links, different from the first link, wherein the information regarding the start of the transmission prohibition period is information expressed based on a TBTT (Target Beacon Transmission Time) of the second link. . Effect of the Invention

[0009] According to the present invention, it is possible to appropriately manage links in multi-link communication. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 illustrates an example of a network configuration. [Diagram 2] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Diagram 3] FIG. 2 illustrates an example of a functional configuration of a communication device. [Figure 4] 11 is a sequence diagram showing an example of a process including a process in which the communication device 102 makes a link quiet. FIG. [Diagram 5] 11 is a flowchart showing a process executed by the communication device 102 when the link is made quiet. [Figure 6] 11 is a flowchart showing a process executed by the communication device 103 when controlling the prohibition of link transmission or its release. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0012] [Network configuration] FIG. 1 shows an example of a network configuration according to this embodiment. The communication device 102 is an AP MLD (Access Point Multi-Link Device) that has a role of constructing a network 101 and is capable of multi-link communication. The communication device 102 is logically composed of multiple APs, each of which can construct one or more links with a STA. The network 101 is a wireless network constructed by the communication device 102. In this embodiment, when the communication device 102 constructs multiple networks, the BSSIDs (Basic Service Set Identifiers) of the networks may all be the same or may be different. The BSSID is an identifier for identifying the network. The SSIDs (Service Set Identifiers) shown by the communication device 102 in each network may also be the same or may be different. The SSID is an identifier for identifying an access point.

[0013] The communication device 103 is a Non-AP MLD (Non-Access Point Multi-Link Device) that has the role of participating in the network 101 and is capable of multi-link communication. The communication device 103 is logically composed of multiple STAs, each of which can establish one or more links with an AP.

[0014] Each communication device is compatible with the IEEE802.11be (EHT (Extremely / Extreme High Throughput)) standard and can execute wireless communication conforming to the IEEE802.11be standard via the network 101. Each communication device can communicate in the frequency bands of 2.4 GHz, 5 GHz, and 6 GHz. 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 be used. Also, each communication device can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0015] Furthermore, each communication device can execute OFDMA (Orthogonal Frequency Division Multiple Access) communication conforming to the IEEE802.11be standard. By executing OFDMA communication, the communication device 102 can realize multi-user (MU) communication in which signals of multiple users are multiplexed. In OFDMA communication, a part (RU (Resource Unit)) of the divided frequency band is assigned to each STA so as not to overlap, and the carriers assigned to each STA are orthogonal. Therefore, the communication device 102 can communicate with multiple STAs in parallel.

[0016] Moreover, each communication device executes multi-link communication, which establishes links via multiple frequency channels for communication. Here, the frequency channel is a frequency channel defined in the IEEE802.11 series standard, and refers to a frequency channel capable of executing wireless communication conforming to the IEEE802.11 series standard. In the IEEE802.11 series standard, multiple frequency channels are defined in each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. In addition, in the IEEE802.11 series standard, the bandwidth of each frequency channel is defined as 20 MHz. Note that a bandwidth of 40 MHz or more may be used in one frequency channel by bonding with adjacent frequency channels.

[0017] In Fig. 1, for example, the communication device 102 can establish a first link 104 via a first frequency channel in the 5 GHz band and a second link 105 via a second frequency channel in the 2.4 GHz band with the communication device 103 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. In this way, the communication device 102 can improve the throughput in communication with the communication device 103 by establishing links with the communication device 103 via multiple frequency channels.

[0018] In addition, the communication device 102 and the communication device 103 may establish a plurality of links of different frequency bands in the multi-link communication. For example, the communication device 102 and the communication device 103 may establish a third link (not shown) in the 6 GHz band in addition to the first link 104 in the 5 GHz band and the second link 105 in the 2.4 GHz band. Alternatively, the communication device 102 and the communication device 103 may establish links via a plurality of different channels included in the same frequency band. For example, the communication device 102 and the communication device 103 may establish the first link 104 via 1ch in the 2.4 GHz band and the second link 105 via 5ch in the 2.4 GHz band.

[0019] Also, links with the same frequency band and links with different frequency bands may be mixed. For example, the communication device 102 and the communication device 103 may establish a first link 104 via 1ch in the 2.4GHz band, a second link 105 via 5ch in the 2.4GHz band, and a third link (not shown) via 52ch in the 5GHz band. By establishing a plurality of connections with the communication device 103 using different frequency bands, the communication device 102 can communicate using the other band even when one band is congested, thereby preventing a decrease in throughput in communication with the communication device 103.

[0020] When performing multi-link communication, the communication device 102 and the communication device 103 can divide one piece of data and transmit it to a communication partner device via multiple links. Alternatively, the communication device 102 and the communication device 103 may transmit the same data via each of the multiple links, so that the communication via one link serves as a backup communication for the communication via the other link. Specifically, the communication device 102 transmits the same data to the communication device 103 via the first link 104 via the first frequency channel and the second link 105 via the second frequency channel. In this case, even if an error occurs in the communication via the first link 104, for example, the communication device 103 can receive the data transmitted from the communication device 102 because the same data is transmitted via the second link 105.

[0021] Alternatively, when performing multi-link communication, the communication device 102 and the communication device 103 may use different links depending on the type of frame and the type of data to be communicated. For example, the communication device 102 may transmit a management frame conforming to the IEEE802.11 series standard via the second link 105, and transmit a data frame including data via the first link 104. Of course, the management frame may be transmitted and received via the first link 104 and the second link 105. Note that the management frame is a MAC (Media Access Control) frame, and specifically refers to a Beacon frame, a Probe Request frame / Response frame, and an Association Request frame / Response frame. In addition to these frames, a Disassociation frame, an Authentication frame, a De-Authentication frame, an Action frame, and the like are also called management frames.

[0022] A Beacon frame is a frame that reports network information. A Probe Request frame is a frame that requests network information, and a Probe Response frame is a response to that, providing the network information. An Association Request frame is a frame that requests a connection, and an Association Response frame is a response to that, indicating permission for connection or an error. A Disassociation frame is a frame that cuts off a connection. An Authentication frame is a frame that authenticates a communication partner device, and a De-Authentication frame is a frame that interrupts authentication of a communication partner device and cuts off a connection. An Action frame is a frame for performing additional functions other than those mentioned above.

[0023] In addition, when the communication device 102 transmits data regarding a captured image, for example, meta-information such as the date, parameters at the time of capturing the image (aperture value and shutter speed), and location information may be transmitted via the second link 105, and pixel information may be transmitted via the first link 104.

[0024] Furthermore, the communication device 102 and the communication device 103 may be capable of performing MIMO (Multiple-Input Multiple-Output) communication. In this case, the communication device 102 and the communication device 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. In this way, by performing MIMO communication, the communication device 102 and the communication device 103 can communicate more data in the same time compared to when not performing MIMO communication. Furthermore, the communication device 102 and the communication device 103 may perform MIMO communication in some links when performing multi-link communication.

[0025] In this embodiment, when the communication device 102 and the communication device 103 establish a link for multi-link communication, they each hold information related to the operation of the established link. The information related to the operation of the link includes the number of spatial streams used in MIMO communication and the communication bandwidth. These operation parameters are determined when the communication device 102 and the communication device 103 establish a link, but may be changed after the link is established. For example, it is assumed that the frequency channel adjacent to the frequency channel used in the link becomes congested, so that the bandwidth is changed to be narrowed. Alternatively, it is assumed that the frequency channel used in the link becomes congested, so that the MIMO communication that was being executed is terminated. In this way, when the operation parameters of the multi-link communication are changed, the communication device 102 and the communication device 103 need to share the new operation parameters as soon as possible.

[0026] Although the communication device 102 and the communication device 103 are described as being compatible with the IEEE802.11be standard, they may also be compatible with at least one of the legacy standards that are standards prior to the IEEE802.11be standard. The legacy standards are the IEEE802.11a / b / g / n / ac / ax standards. In this embodiment, at least one of the IEEE802.11a / b / g / n / ac / ax / be standards is called the IEEE802.11 series standard. In addition to the IEEE802.11 series standard, they may also be compatible with other communication standards such as Bluetooth (registered trademark), NFC (Near Field Communication), UWB (Ultra Wide Band), Zigbee, and MBOA (Multi Band OFDM Alliance). UWB includes wireless USB, wireless 1394, Winet, and the like. They may also be compatible with a communication standard for wired communication such as a wired LAN.

[0027] Specific examples of the communication device 102 (AP MLD) 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 be an information processing device such as a wireless chip capable of performing wireless communication conforming to the IEEE802.11be standard. Specific examples of the communication device 103 (Non-AP MLD) include, but are not limited to, a camera, a tablet, a smartphone, a PC, a mobile phone, a video camera, and the like. The communication device 103 may be any communication device capable of performing multi-link communication with other communication devices. The communication device 103 may be an information processing device such as a wireless chip capable of performing wireless communication conforming to the IEEE802.11be standard. The network in FIG. 1 is a network configured by one AP MLD and one Non-AP MLD, but the number of AP MLDs and Non-AP MLDs is not limited to this. The information processing device such as a wireless chip may have an antenna for transmitting the generated signal.

[0028] 1, the communication device 102 is an AP MLD device and the communication device 103 is a Non-AP MLD device, but this is not limiting, and both the communication device 102 and 103 may be Non-AP MLD devices. In this case, the communication device 102 is a Non-AP MLD device, but can operate as a device having a role of constructing a wireless network for establishing a link with the communication device 103.

[0029] [Communication device configuration] The configuration of the communication device in this embodiment will be described. Fig. 2 shows an example of the hardware configuration of the communication device 102. The communication device 103 also has a similar hardware configuration. The communication device 102 has 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 as an example of the hardware configuration.

[0030] The storage unit 201 is configured with one or more memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and stores various information such as computer programs for performing various operations described below and communication parameters for wireless communication. Note that, in addition to memories such as ROM and RAM, 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 may be used as the storage unit 201. Furthermore, the storage unit 201 may include multiple memories.

[0031] The control unit 202 is configured with one or more processors such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), 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 may generate data and signals (wireless frames) to be transmitted in communication with other communication devices (see FIG. 3). The control unit 202 may include multiple processors such as multi-core processors, and may control the entire communication device 102 using the multiple processors. The control unit 202 controls the function unit 203 to execute predetermined processes such as wireless communication, imaging, printing, and projection. The function unit 203 is hardware for the communication device 102 to execute predetermined processes.

[0032] The input unit 204 receives various operations from the user. The output unit 205 performs various outputs to the user via a monitor screen or a speaker. Here, the output by the output unit 205 may be a display on a monitor screen, a voice output by a speaker, a vibration output, or the like. Note that both the input unit 204 and the output unit 205 may be realized by one module, such as a touch panel. Also, the input unit 204 and the output unit 205 may be integrated with the communication device 102, or may be separate.

[0033] The communication unit 206 controls wireless communication conforming to the IEEE802.11be standard. The communication unit 206 may control wireless communication conforming to other IEEE802.11 series standards in addition to the IEEE802.11be 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 a plurality of communication units 206. When establishing multiple links in multi-link communication, the communication device 102 having a plurality of communication units 206 establishes at least one link per communication unit 206. Alternatively, the communication device 102 may establish multiple links using one communication unit 206. In this case, the communication unit 206 executes communication via multiple links by switching frequency channels that operate in a time-division manner. Note that, when the communication device 102 supports the NFC standard, the Bluetooth standard, and the like in addition to the IEEE802.11be standard, the communication device 102 may control wireless communication conforming to these communication standards. Furthermore, when the communication device 102 can perform wireless communication conforming to a plurality of communication standards, it may be configured to have a communication unit and an antenna corresponding to each communication standard separately. 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 as a separate unit from the communication unit 206, or may be configured together with the communication unit 206 as a single module.

[0034] 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 may have a different antenna for each frequency band. In addition, when the communication device 102 has multiple antennas, it may have a communication unit 206 corresponding to each antenna.

[0035] Fig. 3 shows an example of the functional configuration of the communication device 102. Note that the communication device 103 also has a similar functional configuration (in the case of the communication device 103, the communication partner device in the following explanation of Fig. 3 is the communication device 102). The communication device 102 has, as an example of the functional configuration, a Quiet state control unit 301, a Power Save state management unit 302, a MAC frame generation unit 303, and a frame transmission / reception unit 304.

[0036] The quiet state control unit 301 determines to put a certain link out of the multilinks established with the communication partner device (communication device 103) into the quiet state in order for the communication device 102 to perform radar wave observation, noise measurement, etc. for DFS (Dynamic Frequency Selection). There may be one or more links to be made quiet, but here, the description will be given assuming that there is only one link. The quiet state control unit 301 can also determine the period during which the link is made quiet (period during which transmission by the communication partner device is prohibited (quiet period)). The quiet state control unit 301 may determine the link to be made into the quiet period and / or the quiet period based on a user instruction. The quiet period may also be a predetermined periodic period.

[0037] When the link to be made quiet is determined by the quiet state control unit 301, the frame transmission / reception unit 304, which will be described later, notifies the prohibition of transmission on that link via a link other than the link to be made quiet. For example, in the configuration of Fig. 1, the quiet state control unit 301 determines to make the first link 104 quiet, and the frame transmission / reception unit 304 can notify (request) the communication partner device via the second link 105 that transmission on the link 104 is prohibited.

[0038] The power save state management unit 302 manages whether or not a certain link among the multiple links established with the communication partner device (communication device 103) is put into the power save state. There may be one or more links put into the power save state, but here, the description will be given assuming one link. Putting a link into the power save state refers to transitioning to a state in which communication is not performed using the link subject to power save. Here, not communicating means that data frames are not communicated. In addition, the link subject to power save may be set so that management frames are not communicated and / or may be transitioned to a doze state so that reception is not performed.

[0039] When the communication device 102 has a communication unit 206 for each link, the control unit 202 may temporarily stop or reduce the power supply to the communication unit 206 corresponding to the link that transitions to the Power Save state. In this embodiment, a state in which a link is in communication is called a Wakeup state, as opposed to a Power Save state. When the communication device 102 has a communication unit 206 for each link, the power supplied to the communication unit 206 corresponding to the link in the Power Save state is less than the power supplied to the communication unit 206 corresponding to the link in the Wakeup state. Also, the communication unit 206 corresponding to the link in the Power Save state consumes less power than the communication unit 206 corresponding to the link in the Wakeup state.

[0040] The power save state management unit 302 may set a link to a power save state or a wakeup state, the link being indicated in a MAC frame indicating a power save state received from a communication partner device (communication device 103) by the frame transmission / reception unit 304. Alternatively, the power save state management unit 302 may set a certain link to a power save state or a wakeup state in response to an instruction from a user via the input unit 204 or the like.

[0041] Furthermore, the power save state management unit 302 may put a link into a power save state or into a wakeup state based on the state of data communication with a communication partner device (communication device 103) via the frame transmission / reception unit 304. For example, when the amount of data to be transmitted to the communication device 103 is less than a predetermined threshold, the power save state management unit 302 may transition some of the multiple links established with the communication device 103 into a power save state. On the other hand, when the amount of data to be transmitted to the communication device 103 is greater than a predetermined threshold, the power save state management unit 302 may transition a link with the communication device 103 that was in a power save state into a wakeup state. Alternatively, the power save state management unit 302 may transition another link with the communication device 103 that was in a power save state into a wakeup state based on a decrease in the throughput of a link that was used for data communication with the communication device 103. In this case, the power save state management unit 302 may transition the original link that was used for data communication from the wakeup state to the power save state.

[0042] The MAC frame generating unit 303 generates a MAC (Media Access Control) frame. The MAC frames generated by the MAC frame generating unit 303 are various management frames such as a Beacon, a Probe Response, and a FILS (Fast Initial Link Setup) Discovery. When the quiet state control unit 301 decides to make the first link 104 quiet, the MAC frame generating unit 303 generates a Beacon or Probe Response frame including a Quiet element to be transmitted by the first link 104. The Quiet element may include information similar to a "transmission inhibition period" described below as information on the period during which the target link is made quiet (quiet period).

[0043] The MAC frame generation unit 303 further generates a Beacon, Probe Response, or FILS Discovery frame including information for notifying the second link 105 of the transmission prohibition on the first link 104. The information for notifying the transmission prohibition on the target link is hereinafter referred to as "transmission prohibition information."

[0044] The transmission prohibition information may include information for identifying a link for which transmission is prohibited. The transmission prohibition information may also include information indicating whether a link is transmission prohibited or transmission prohibition has been lifted. The transmission prohibition / transmission prohibition lifted information may be composed of 1 bit, and the value 0 may indicate that transmission is not prohibited, and the value 1 may indicate that transmission prohibition has been lifted. This bit will be hereinafter referred to as the "transmission prohibition bit." By including the transmission prohibition bit in the transmission prohibition information, the MAC frame generation unit 303 can generate a frame for notifying the link status through simple processing. Furthermore, the receiving side of the MAC frame can determine the link status from the received frame through simple processing.

[0045] The transmission prohibition information may also include information indicating a period during which transmission is prohibited. Hereinafter, this period is referred to as the "transmission prohibition period." The transmission prohibition period may be expressed by three pieces of information based on the TBTT (Target Beacon Transmission Time), which indicates the transmission timing of the Beacon frame. The three pieces of information are (1) Quiet Count, (2) Quiet Offset, and (3) Quiet Duration. (1) Quiet Count is the number of TBTTs until the Beacon Interval at which the transmission prohibition period begins. (2) Quiet Offset is the offset from the TBTT specified by the Quiet Count to the beginning of the transmission prohibition period. (3) Quiet Duration is the length of the transmission prohibition period. (2) Quiet Offset and (3) Quiet Duration may be expressed in units of TU (Time Unit) defined in the IEEE802.11 series standards.

[0046] The reference TBTT may be the TBTT in the first link 104. In this case, the above three pieces of information may be information in the same-named fields included in the Quiet element.

[0047] On the other hand, the reference TBTT may be the TBTT in the second link 105. In this case, the values ​​of (1) Quiet Count and (2) Quiet Offset are values ​​that express the time when the quiet period in the first link 104 starts, based on the TBTT of the link 104. By setting the reference TBTT to the TBTT in the second link 105, the communication device 102 can accurately recognize the transmission inhibition period even if the first link 104 has been in the Doze state for a long period of time, has not received a Beacon frame, and does not know the TBTT.

[0048] When the transmission prohibition information includes a transmission prohibition bit but does not include a transmission prohibition period, the length of the frame including the transmission prohibition information can be shortened, thereby enabling efficient use of the communication band. Also, when the transmission prohibition period is included in the transmission prohibition information, it is not necessary to transmit a frame including the transmission prohibition information indicating that the prohibition of transmission has been lifted, thereby enabling efficient use of the communication band.

[0049] Incidentally, the MAC frame generating unit 303 may generate a data frame or the like in addition to or instead of the management frame.

[0050] The frame transmitting / receiving unit 304 transmits wireless frames including the MAC frame generated by the MAC frame generating unit 303 and receives wireless frames from the communication partner device (communication device 103) via the communication unit 206 and the antenna 207. The frame transmitting / receiving unit 304 can further control frame communication. For example, the frame transmitting / receiving unit 304 can control the stopping (prohibition) of frame transmission for a predetermined period (quiet period, transmission prohibited period).

[0051] [Processing flow by communication device 102 and communication device 103] Next, a process in which the communication device in this embodiment makes a link quiet will be described. FIG. 4 is a sequence diagram showing an example of a process including a process in which the communication device 102 makes the first link 104 quiet. In this embodiment, the communication device 102 and the communication device 103 establish two links (the first link 104 and the second link 105) to perform multi-link communication. The first link 104 is a link using a first frequency channel (e.g., 52ch in the 5GHz band), and the second link 105 is a link using a second frequency channel (e.g., 1ch in the 2.4GHz band). The process of this sequence can be started after the links are established by the Multi-Link Setup process.

[0052] In F401, the communication device 103 transmits a QoS Null frame with the Power Management bit set to 1 to the communication device 102 via the first link 104. As a result, the communication device 103 notifies the communication device 102 that the first link 104 will be transitioned to a power save state. Next, in F402, the communication device 103 transitions the first link 104 to a power save state. At this time, in this embodiment, the communication device 103 transitions the first link 104 to a doze state in which communication, including reception of frames / signals, is not possible.

[0053] In the present embodiment, the communication device 103 transitions the link (first link 104) that has transmitted the QoS Null frame to a power save state, but this is not limiting. For example, the communication device 103 may transmit a QoS Null frame including information indicating the first link 104 via the second link 105, and then transition the first link 104 to a power save state. In this case, the communication device 103 does not transition the second link 105 that has transmitted the QoS Null frame to a power save state. The communication device 103 may include, in the QoS Null frame, an identifier that makes the first link 104 identifiable from other links, as information indicating the first link 104. In addition to this, or instead of this, the communication device 103 may include, in the QoS Null frame, information indicating the BSSID of the wireless network in which the first link 104 is established, or information indicating the first frequency channel.

[0054] Next, in F403, the communication device 102 transmits a Probe Response frame including transmission prohibition information for notifying the communication device 103 of the transmission prohibition of the first link 104 via the second link 105. Here, the destination of the Probe Response frame may be only the communication device 103, or may be a group consisting of multiple STAs or Non-AP MLDs. Alternatively, the frame may be transmitted by broadcast. Also, as described above, a Beacon frame may be transmitted here instead of the Probe Response frame. As described above, the transmission prohibition information may include information for identifying the link for which transmission is prohibited, a transmission prohibition bit, a transmission prohibition period, and the like.

[0055] After transmitting the Probe Response frame, the communication device 102 transmits a Beacon frame including a Quiet element for making the first link 104 Quiet in F404, via the first link 104. Note that the transmission of the Probe Response frame including the transmission prohibition information (F403) may be performed before the Quiet period starts. That is, the transmission of the Probe Response frame including the transmission prohibition information (F403) may be performed before, after, or simultaneously with the transmission of the Beacon frame including the Quiet element (F404). When the Beacon frame in F404 is transmitted, the communication device 102 makes the first link 104 Quiet during F405 to F406 (Quiet period) based on the contents of the Quiet element included in the frame. The communication device 102 may transmit a Beacon frame not including a Quiet element during the Quiet period. Depending on conditions, the transmission of a probe response frame including transmission prohibition information (F403) may be permitted to occur after the quiet period has started.

[0056] On the other hand, since the communication device 103 is in the Doze state, it cannot receive the Beacon frame (F404) including the Quiet element transmitted from the communication device 102. However, since the communication device 103 receives the Probe Response frame (F403) including transmission prohibition information via the second link 105, it can recognize the Quiet period (transmission prohibition period). Therefore, even if there is data to be transmitted during the Quiet period, the communication device 103 does not transition the first link 104 to the Wakeup state and transmit the data via that link.

[0057] After the quiet period has elapsed (when the period ends), the communication device 102 transmits a Probe Response frame including transmission prohibition information indicating lifting of the prohibition of transmission on the first link 104 to the communication device 103 via the second link 105 in F407. Here, the destination of the Probe Response frame may be only the communication device 103, or may be a group consisting of multiple STAs or Non-AP MLDs. Alternatively, the frame may be transmitted by broadcast. Note that if the Probe Response frame transmitted in F403 includes information indicating the transmission prohibition period, the Probe Response frame in F407 does not need to be transmitted.

[0058] Upon receiving the Probe Response frame at F407, the communication device 103 releases the Power Save state of the first link 104 at F408, and transitions the link to a Wakeup state. This transitions the communication device 103 from a state in which communication via the first link 104 cannot be performed to a state in which communication can be performed. Note that, if the Probe Response frame received at F403 includes information indicating a transmission inhibition period for the first link 104, the communication device 103 may transition the link to a Wakeup state after the transmission inhibition period indicated in the frame ends.

[0059] When the communication device 103 transitions the first link 104 to the Wakeup state, in F409, it transmits a QoS Null frame with the Power Management bit set to 0 to the communication device 102. This allows the communication device 103 to notify the communication device 102 that it has transitioned the first link 104 to the Wakeup state. Note that this QoS Null frame does not necessarily have to be transmitted. Next, in F410, the communication device 103 executes transmission of a data frame via the first link 104 that is now in the Wakeup state.

[0060] In this way, before the quiet period of the first link 104 starts, the communication device 102 transmits a frame including transmission prohibition information that prohibits transmission on that link to the communication device 103. In this way, when the first link 104 is in the Doze state, the communication device 103 can prevent the first link 104 from being put into the Wakeup state and transmitting frames / signals at least during the quiet period.

[0061] [Processing by communication device 102] Fig. 5 is a flowchart showing a process executed by the control unit 202 reading and executing a computer program stored in the storage unit 201 when the communication device 102 makes a link quiet. The process of this flowchart can be started when the communication device 102 decides to make one of the links quiet after establishing a multi-link consisting of the first link 104 and the second link 105 by the Multi-Link Setup process. Fig. 5 will be described assuming that the communication device 102 decides to make the first link 104 quiet (prohibiting transmission by the communication partner device) as in the example of Fig. 4.

[0062] The MAC frame generating unit 303 of the communication device 102 generates a Probe Response frame including transmission prohibition information notifying the prohibition of transmission on the first link 104 (the link to be made quiet). Then, the frame transmitting / receiving unit 304 of the communication device 102 transmits the Probe Response frame to the communication device 103 on the second link 105, which is a link different from the link to be made quiet, and waits for the completion of the transmission (steps S501 to S502).

[0063] When the transmission of the Probe Response frame is completed (Yes in step S502), the MAC frame generating unit 303 of the communication device 102 generates a Beacon frame including a Quiet element. Then, the frame transmitting / receiving unit 304 of the communication device 102 transmits the Beacon frame through the first link 104, which is the link to be made Quiet, and waits for the completion of the transmission (steps S503 to S504).

[0064] When the transmission of the Beacon frame is completed (Yes in step S504), the communication device 102 resumes the transmission of the normal Beacon frame (step S505). That is, the MAC frame generating unit 303 of the communication device 102 generates a Beacon frame that does not include a Quiet element, and the frame transmitting / receiving unit 304 continues to transmit the Beacon frame.

[0065] Note that the communication device 102 may continue to transmit a Beacon frame including a Quiet element while updating the Quiet period (for example, while updating the value of Quiet Count) until the Quiet period starts in steps S503 to S504. That is, the communication device 102 may continue to transmit a Beacon frame including a Quiet element including a Quiet period (value of Quiet Count) updated according to time until the Quiet period starts. Then, the communication device 102 may execute the process of step S505 after completing the transmission of the last Beacon frame transmitted before the Quiet period starts.

[0066] In step S506, the quiet state control unit 301 of the communication device 102 waits for the quiet period of the first link 104 to end. When the quiet period ends (Yes in step S506), in step S507, the MAC frame generation unit 303 of the communication device 102 generates a Probe Response frame including transmission prohibition information notifying the lifting of the transmission prohibition on the first link 104. Then, the frame transmission / reception unit 304 transmits the Probe Response frame to the communication device 103 via the second link 105 and waits for the completion of the transmission (steps S507 to S508). When the transmission of the Probe Response frame is completed (Yes in step S508), the communication device 102 ends the process.

[0067] The destination of the Probe Response frame (steps S501 and S507) including the transmission prohibition information may be only the communication device 103, or may be a group consisting of multiple STAs or Non-AP MLDs. Alternatively, the frame may be transmitted by broadcast. Also, the Probe Response frame does not have to be transmitted to STAs or Non-AP MLDs in which the first link 104 is in a Wakeup state or in a state in which it can receive a Quiet Element even in a Power Save state. In this case, the processes from steps S501 to S502 and from steps S507 to S508 may be skipped.

[0068] 5, the communication device 102 transmits a Probe Response frame notifying transmission prohibition (steps S501 to S502) before transmitting a Beacon frame including a Quiet element (steps S503 to S504). Alternatively, the Probe Response frame may be transmitted simultaneously with or after the Beacon frame including the Quiet element, as long as it is before the Quiet period starts.

[0069] [Processing by communication device 103] Fig. 6 is a flowchart showing a process executed by the control unit 202 reading and executing a computer program stored in the storage unit 201 when the communication device 103 controls the link transmission prohibition or release. This flowchart can be started after the communication device 103 establishes a multi-link consisting of the first link 104 and the second link 105 by the Multi-Link Setup process. Fig. 6 explains the process assuming that the communication device 102 decides to make the first link 104 Quiet (transmission prohibited by the communication partner device) as in the example of Fig. 4.

[0070] When the frame transmitting / receiving unit 304 of the communication device 103 receives a Probe Response frame including transmission prohibition information indicating that transmission on the first link 104 is prohibited (Yes in step S601), it determines that the first link 104 is in a transmission prohibition state. Here, it is assumed that the Probe Response frame is received on the second link 105, which is a link other than the link to be made quiet. Then, the frame transmitting / receiving unit 304 sets (controls) so as not to transmit frames on the first link 104 until the transmission prohibition state is released. If the received transmission prohibition information includes information on a transmission prohibition period, the frame transmitting / receiving unit 304 may be set so as not to transmit frames for only that period. If a Probe Response frame including transmission prohibition information is not received (No in step S601), the process of step S602 is skipped.

[0071] Next, when the frame transmitting / receiving unit 304 of the communication device 103 receives a Beacon frame including a Quiet element (Yes in step S603), it determines that the link that received the frame is in a transmission prohibited state during the Quiet period indicated by the Quiet element. In this example, it is assumed that the link that received the Quiet element is the first link 104. Then, the frame transmitting / receiving unit 304 sets (controls) the first link 104, which is the link that received the Quiet element, not to transmit frames during the period (step S604). Here, if the Power Save state management unit 302 determines that the Quiet element has not been received because the first link 104 is in a Doze state (No in step S603), the process of step S604 is skipped.

[0072] Next, the frame transmitting / receiving unit 304 of the communication device 103 stops transmitting frames through the first link 104, which is the link through which the quiet element was received, in accordance with the quiet period indicated by the quiet element received in step S603. When the quiet period ends (Yes in step S605), the frame transmitting / receiving unit 304 releases the prohibition of transmission through the first link 104, which is the link through which the quiet element was received, in S606, and transmits the frame through that link, if there is a frame to be transmitted. Note that if the communication device 103 has not received a quiet element (No in step S603) and is not aware of the existence of a quiet period, the process of step S606 is skipped.

[0073] Next, when the frame transmitting / receiving unit 304 of the communication device 103 receives a Probe Response frame including transmission prohibition information indicating that the prohibition of transmission on the first link 104 is lifted (Yes in step S607), it determines that the prohibition of transmission on the first link 104 is lifted. Then, the frame transmitting / receiving unit 304 of the communication device 103 lifts the prohibition of transmission on the first link 104 (step S608), and transmits the frame on that link if there is a frame to be transmitted. Note that, if the transmission prohibition information included in the Probe Response frame received in step S601 includes a transmission prohibition period, the frame transmitting / receiving unit 304 of the communication device 103 may determine that the prohibition of transmission on the first link 104 is lifted when that period ends.

[0074] Next, when the communication device 103 is instructed by the user to end the Multi-Link Data Transmission because there is no data to be transmitted, etc., the process ends (Yes in step S609). Otherwise (No in step S609), the process returns to step S601.

[0075] Thus, according to the present embodiment, even if Non-AP MLD puts a link that should be quiet in a multi-link communication in a state where it cannot receive frames, information about the link that should be quiet is notified by another link. This allows AP MLD to appropriately execute desired processing on the link that should be quiet.

[0076] In the present embodiment, the communication device 102 transmits the Quiet element by including it in the Beacon frame. However, the Quiet element may be transmitted by including it in the Probe Response frame.

[0077] In this embodiment, the communication device 102 uses a Quiet element to notify the channel to be made quiet on the channel. Instead of this, a Channel Switch Announcement element or an Extended Channel Switch Announcement element with a Channel Switch Mode field value of 1 may be used to indicate that the channel to be used on the link to be made quiet is to be moved (changed). That is, the communication device 102 may notify that the channel to be used on the link to be made quiet is to be moved by transmitting a frame including such an element. After transmitting a frame including such an element, the communication device 102 moves the channel to be used on the link that transmitted the frame. In this case, the processes of steps S505 to S508 may be skipped in the flowchart shown in FIG. 5, which shows the process executed when the communication device 102 makes a link quiet. In this case, instead of (or in addition to) transmitting a frame including transmission prohibition information (e.g., F403 in FIG. 4), the communication device 102 may transmit a frame including information for indicating that the channel to be used on the link to be made quiet (the first link 104 in the example of FIG. 4) is to be moved.

[0078] In this embodiment, the communication device 102 transmits the transmission prohibition information by including it in a Probe Response frame. Here, the Probe Response frame can be transmitted at any timing based on the method of Distributed Coordination Function (DCF) defined in the IEEE802.11 standard. Therefore, after the communication device 102 determines to make a specific link (the first link 104 in this embodiment) quiet, it can promptly notify the communication device 103 of the determination.

[0079] Furthermore, the communication device 102 may transmit the transmission prohibition information by including it in a Beacon frame that is transmitted periodically or a FILS Discovery frame that is transmitted at a shorter period than the Beacon. In this case, a frame only for transmitting the transmission prohibition information is not transmitted, so that the communication band can be used efficiently.

[0080] At least a part or all of the flowcharts of the communication device 102 and the communication device 103 shown in Fig. 5 and Fig. 6, respectively, may be realized by hardware. When the flowcharts are realized by hardware, for example, a specific compiler may be used to generate a dedicated circuit on an FPGA (Field Programmable Gate Array) from a computer program for realizing each step, and this may be used. Alternatively, a gate array circuit may be formed in the same manner as the FPGA, and the hardware may be realized. Alternatively, the hardware may be realized by an ASIC (Application Specific Integrated Circuit).

[0081] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0082] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0083] 101 network, 102 communication device (AP MLD), 103 communication device (Non-AP MLD), 104 first link, 105 second link

Claims

1. A communication device, comprising: a determining means for determining a first link, among a plurality of links established with a communication partner device, as a link for which transmission is to be prohibited by the communication partner device, and a transmission prohibition period for the first link; a transmitting means for transmitting a first frame including information about the transmission inhibition period on the first link, via a second link different from the first link among the plurality of links, before the transmission inhibition period starts; The information on the transmission prohibition period is information expressed based on a Target Beacon Transmission Time (TBTT) of the second link. A communication device comprising:

2. A communication device, a determination means for determining a first link to be set as a link for which transmission is prohibited by the communication partner device among a plurality of links established with the communication partner device, and a timing for determining a start of a transmission prohibition period for the first link; a transmitting means for transmitting a first frame including information on a start timing of the transmission inhibition period in the first link and information indicating a change in a channel of the first link, via a second link different from the first link among the plurality of links before the transmission inhibition period starts; The information regarding the timing at which the transmission prohibition period starts is information expressed based on a Target Beacon Transmission Time (TBTT) of the second link. A communication device comprising:

3. 2. The communication device according to claim 1, wherein the determining means determines the first link and / or the transmission inhibition period based on an instruction from a user.

4. 3. The communication device according to claim 2, wherein the determining means determines the timing of the start of the first link and / or the transmission inhibition period based on an instruction from a user.

5. 5. The communication device according to claim 1, wherein the transmission inhibition period is a periodic period.

6. The communication device as described in Claim 1, characterized in that the first frame further includes information regarding the timing at which the transmission prohibition period begins.

7. The communication device described in any one of claims 1 to 6, characterized in that the communication device complies with the IEEE 802.11 series standards and is capable of communication over multiple links.

8. 8. The communication device according to claim 1, wherein the transmitting means transmits a second frame including information regarding lifting the transmission prohibition on the first link after the transmission prohibition period has elapsed.

9. 9. The communication device according to claim 1, wherein the first frame is a Probe Response frame or a Beacon frame.

10. The communication device according to claim 8 , wherein the second frame is a probe response frame, a beacon frame, or a fast initial link setup (FILS) discovery frame.

11. The communication device according to any one of claims 1 to 10, characterized in that the communication device is an Access Point Multi-Link Device (AP MLD).

12. A method for controlling a communication device, comprising: a determining step of determining a first link, among a plurality of links established with a communication partner device, to be set as a link for which transmission is prohibited by the communication partner device, and a transmission prohibition period for the first link; a transmitting step of transmitting a first frame including information of the transmission inhibition period on the first link through a second link different from the first link among the plurality of links before the transmission inhibition period starts; The information on the transmission prohibition period is information expressed based on a Target Beacon Transmission Time (TBTT) of the second link. A control method comprising:

13. A method for controlling a communication device, comprising: a determining step of determining a first link, among a plurality of links established with a communication partner device, to be set as a link for which transmission is prohibited by the communication partner device, and a timing for determining a start time of a transmission prohibition period for the first link; a transmitting step of transmitting a first frame including information regarding a timing at which the transmission inhibit period in the first link starts and information indicating a change in a channel of the first link, via a second link different from the first link among the plurality of links before the transmission inhibit period starts; The information regarding the timing at which the transmission prohibition period starts is information expressed based on a Target Beacon Transmission Time (TBTT) of the second link. A control method comprising:

14. A program for causing a computer to function as the communication device according to any one of claims 1 to 11.

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