Communication device, communication method, and program

Abstract

To provide a communication device that, when changing information related to the operation of a first link established with the other communication device, allows the other communication device to appropriately share information related to the operation of a new first link.SOLUTION: A communication device 102, when changing information related to the operation of a first link established with a communication device 103 in a frequency channel in which wireless communication conforming to the IEEE802.11 series standard can be executed, notifies the communication device 103 of information related to the operation of the first link after the change through a second link with the communication device 103 different from the first link.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to notification of information relating to link operation in wireless communication. [Background technology]

[0002] The IEEE802.11 series is known as a WLAN communication standard established 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 a link is established when an AP and a STA communicate with each other.

[0003] To further improve throughput and frequency utilization efficiency, the IEEE is considering the formulation of the IEEE802.11be standard as a new standard in the IEEE802.11 series. The IEEE802.11be standard considers multi-link communication, in which a single access point (AP) establishes multiple links with a single station (STA) via multiple different frequency channels. [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 multi-link communication, it is conceivable that operational information (e.g., bandwidth) of an established link may be changed. However, for example, if interference from another device occurs on the link whose operational information is to be changed, even if new operational information is transmitted via that link, it may take a long time for the information to reach the other device. Alternatively, for example, if data communication is being performed on the link whose operational information is to be changed, transmitting new operational information via that link may result in a decrease in throughput.

[0006] In view of the above, the present invention aims to, when information regarding the operation of a first link established with another communication device is changed, ensure that information regarding the operation of the new first link is appropriately shared with the other communication device. [Means for solving the problem]

[0007] In order to achieve the above object, a communication device of the present invention is and communicating an Association Request frame and an Association Response frame using the first frequency channel. establishing means for establishing a first link over one frequency channel and a second link over a second frequency channel; 2 Phosphorus Information about changes to the Power Management of the network Record number 1 and a notification means for notifying the other communication device via the link. [Effects of the Invention]

[0008] According to the present invention, when information regarding the operation of a first link established with another communication device is changed, the information regarding the changed operation of the first link can be notified via a second link, thereby making it possible to appropriately share the information with the other communication device. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a network to which a communication device 102 belongs. [Figure 2] FIG. 2 is a diagram illustrating a hardware configuration of a communication device 102. [Figure 3] FIG. 2 is a diagram illustrating a functional configuration of a communication device 102. [Figure 4] 10 is a sequence diagram showing an example of processing executed when communication devices 102 and 103 change operation parameters of a link. FIG. [Figure 5] FIG. 10 is a diagram illustrating an example of a frame format including operational parameters for a predetermined link. [Figure 6] 10 is a flowchart showing the processing executed by the communication device 102 when changing the operational parameters of a link. [Figure 7] FIG. 10 is a diagram illustrating an example of a frame format including operational parameters for multiple links. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] FIG. 1 shows the configuration of a network in which a communication device 102 according to this embodiment participates. The communication device 102 is an access point (AP) that serves to establish a network 101. The network 101 is a wireless network. In this embodiment, when the communication device 102 establishes multiple networks, the BSSIDs of the networks may all be the same or different. BSSID stands for Basic Service Set Identifier and is an identifier for identifying a network. The SSIDs indicated by the communication device 102 in each network may also be the same or different. SSID stands for Service Set Identifier and is an identifier for identifying an access point.

[0012] Furthermore, the communication devices 103 are stations (STAs) that participate in the network 101. Each communication device is compatible with the IEEE 802.11be (EHT) standard and can perform wireless communication in accordance with the IEEE 802.11be standard via the network 101. Note that IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. Furthermore, EHT is an abbreviation for Extremely High Throughput. Note that EHT may also be interpreted as an abbreviation for Extreme High Throughput. Each communication device can communicate in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. The frequency bands used by each communication device are not limited to these, and a different frequency band, such as the 60 GHz band, may also be used. Furthermore, each communication device can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0013] The communication devices 102 and 103 perform OFDMA communication conforming to the IEEE802.11be standard, thereby realizing multi-user (MU) communication in which signals from multiple users are multiplexed. OFDMA communication stands for Orthogonal Frequency Division Multiple Access. In OFDMA communication, portions of a divided frequency band (RU, Resource Unit) are assigned to each STA so as not to overlap, and the carriers assigned to each STA are orthogonal. This allows an AP to communicate with multiple STAs in parallel.

[0014] Furthermore, the communication devices 102 and 103 perform multi-link communication, establishing links via multiple frequency channels. Here, a frequency channel refers to a frequency channel defined in the IEEE 802.11 series of standards that can perform wireless communication compliant with the IEEE 802.11 series of standards. The IEEE 802.11 series of standards defines multiple frequency channels in each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. The IEEE 802.11 series of standards also defines a bandwidth of 20 MHz for each frequency channel. Note that a single frequency channel may utilize a bandwidth of 40 MHz or more by bonding adjacent frequency channels. For example, the communication device 102 can establish a first link 104 with the communication device 103 via a first frequency channel in the 2.4 GHz band and a second link 105 via a second frequency channel in the 5 GHz band, and communicate via both links. In this case, the communication device 102 maintains a second link 105 via a second frequency channel in parallel with a first link 104 via a first frequency channel. In this way, the communication device 102 can improve the throughput of communication with the communication device 103 by establishing links with the communication device 103 via multiple frequency channels. Note that the communication devices 102 and 103 may establish multiple links in different frequency bands in multi-link communication. For example, the communication devices 102 and 103 may establish a first link 104 in the 2.4 GHz band, a second link 105 in the 5 GHz band, and a third link in the 6 GHz band. Alternatively, links may be established via multiple different channels included in the same frequency band. For example, the first link 104 may be established via channel 1 in the 2.4 GHz band, and the second link 105 may be established via channel 5 in the 2.4 GHz band. Note that links in the same frequency band and links in different frequency bands may be mixed.For example, communication devices 102 and 103 may establish a first link 104 via channel 1 in the 2.4 GHz band, a second link 105 via channel 5 in the 2.4 GHz band, and a third link via channel 36 in the 5 GHz band. By establishing multiple connections with communication device 103 using different frequency bands, communication device 102 can communicate with communication device 103 using the other band even when one band is congested, thereby preventing a decrease in throughput in communication with communication device 103.

[0015] In multi-link communication, the multiple links established between the communication devices 102 and 103 need only have different frequency channels. Note that in multi-link communication, the channel spacing between the frequency channels of the multiple links established between the communication devices 102 and 103 needs only to be at least 20 MHz or greater. Note that in this embodiment, the communication devices 102 and 103 establish a first link 104 and a second link 105, but they may also establish three or more links.

[0016] When performing multi-link communication, the communication devices 102 and 103 divide a single piece of data and transmit it to the other device via multiple links. Alternatively, the communication devices 102 and 103 may transmit the same data via each of the multiple links, with communication via one link serving as a backup for communication via the other link. Specifically, the communication device 102 may transmit the same data to the communication device 103 via a first link via a first frequency channel and a second link via a second frequency channel. In this case, even if an error occurs in communication via the first link, the communication device 103 can receive the data transmitted from the communication device 102 because the same data was transmitted via the second link. Alternatively, the communication devices 102 and 103 may use different links depending on the type of frame or data to be communicated. For example, the communication device 102 may transmit a management frame via the first link and a data frame containing data via the second link. Management frames specifically refer to Beacon frames, Probe Request frames / Response frames, and Association Request frames / Response frames. In addition to these frames, Disassociation frames, Authentication frames, De-Authentication frames, and Action frames are also called management frames. Beacon frames are frames that report network information. Probe Request frames are frames that request network information, and Probe Response frames are their responses, providing network information. Association Request frames are frames that request a connection, and Association Response frames are their responses, indicating permission for the connection or an error. Disassociation frames are frames that cut off a connection.An authentication frame is a frame that authenticates a remote device, and a de-authentication frame is a frame that suspends authentication of the remote device and disconnects the connection. An action frame is a frame that performs additional functions other than those described above. The communication devices 102 and 103 send and receive management frames that comply with the IEEE 802.11 series standards. Alternatively, when transmitting data related to captured images, for example, the communication device 102 may transmit meta-information such as the date, parameters at the time of capture (aperture value and shutter speed), and location information via a first link, and transmit pixel information via a second link.

[0017] The communication devices 102 and 103 may also be capable of MIMO (Multiple-Input And Multiple-Output) communication. In this case, the communication devices 102 and 103 have multiple antennas, and one of them transmits different signals from each antenna using the same frequency channel. The receiving side simultaneously receives all signals arriving from multiple streams using multiple antennas, and separates and decodes the signals of each stream. By performing MIMO communication in this way, the communication devices 102 and 103 can communicate more data in the same amount of time than if they did not perform MIMO communication. Furthermore, when performing multi-link communication, the communication devices 102 and 103 may perform MIMO communication on some of the links.

[0018] In this embodiment, when the communication devices 102 and 103 establish a multilink communication link, they each retain information related to the operation of the link. The information related to the link operation includes the number of spatial streams used in MIMO communication, the communication bandwidth, and the like. These operation-related parameters are determined when the communication devices 102 and 103 establish the link, but may be changed after the link is established. For example, it is assumed that the bandwidth may be narrowed because a frequency channel adjacent to the frequency channel used in the link has become congested. Alternatively, it is assumed that the frequency channel used in the link has become congested, and the MIMO communication that was being performed is terminated. In this way, when the operation parameters of the multilink communication are changed, the communication devices 102 and 103 need to quickly share the new operation parameters. In this embodiment, the communication device 102 transmits information related to the new operation to the communication device 103 via a link other than the link whose operation parameters are changed, thereby enabling the information related to the new operation to be shared with the communication device 103 more quickly.

[0019] Although the communication devices 102 and 103 are described as being compatible with the IEEE 802.11be standard, they may also be compatible with at least one legacy standard that predates the IEEE 802.11be standard. The legacy standard refers to the IEEE 802.11a / b / g / n / ac / ax standards. In this embodiment, at least one of the IEEE 802.11a / b / g / n / ac / ax / be standards is referred to as the IEEE 802.11 series standard. In addition to the IEEE 802.11 series standards, the communication devices 102 and 103 may also be compatible with other communication standards, such as Bluetooth (registered trademark), NFC, UWB, Zigbee, and MBOA. UWB stands for Ultra Wide Band, and MBOA stands for Multi-Band OFDM Alliance. OFDM stands for Orthogonal Frequency Division Multiplexing. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, Wi-Fi, etc. It may also be compatible with wired communication standards such as wired LAN.

[0020] Specific examples of the communication device 102 include, but are not limited to, a wireless LAN router and a PC. The communication device 102 may be any communication device capable of performing multi-link communication with other communication devices. The communication device 102 may also be an information processing device, such as a wireless chip, capable of performing wireless communication in accordance with the IEEE 802.11be standard. Specific examples of the communication device 103 include, but are not limited to, a camera, a tablet, a smartphone, a PC, a mobile phone, and a video camera. The communication device 103 may also be any communication device capable of performing multi-link communication with other communication devices. The communication device 103 may also be an information processing device, such as a wireless chip, capable of performing wireless communication in accordance with the IEEE 802.11be standard. The network in FIG. 1 is a network configured with one AP and one STA, but the number of APs and STAs is not limited to this. The information processing device, such as a wireless chip, has an antenna for transmitting the generated signal.

[0021] 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 devices 102 and 103 may be STAs. In this case, the communication device 102 is an STA, but operates as a device that has a role of constructing a wireless network to establish a link with the communication device 103.

[0022] 2 shows the hardware configuration of the communication device 102 in this embodiment. 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The communication unit 206 controls wireless communication in accordance with the IEEE 802.11be standard. The communication unit 206 may also control wireless communication in accordance with other IEEE 802.11 series standards in addition to the IEEE 802.11be standard, or wired communication such as a wired LAN. The communication unit 206 controls the antenna 207 to transmit and receive signals generated by the control unit 202 for wireless communication. The communication device 102 may have multiple communication units 206. When establishing multiple links in multi-link communication, a communication device 102 having multiple communication units 206 establishes at least one link per communication unit 206. 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 frequency channels operating 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 communication in accordance with these communication standards. Furthermore, if the communication device 102 is capable of wireless communication conforming to multiple communication standards, it may be configured to have separate communication units and antennas corresponding to 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 as a separate unit from the communication unit 206, or may be configured together with the communication unit 206 as a single module.

[0028] 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.

[0029] The communication device 103 has the same hardware configuration as the communication device 102 .

[0030] 3 shows the functional configuration of the communication device 102 in this embodiment. The communication device 102 has an operation parameter change unit 301, an operation parameter acquisition unit 302, a link selection unit 303, a power save state management unit 304, a MAC frame generation unit 305, and a data transmission / reception unit 306. The operation parameters are parameters related to the operation of links in multi-link communication. MAC is an abbreviation for Media Access Control.

[0031] The operational parameter change unit 301 is a block that manages changes to the operational parameters of the links of multilink communication established between the communication device 102 and the other device (communication device 103). The operational parameters of the links are determined when the links are established, but may be dynamically changed even after the links are established. For example, if frequency channels surrounding the frequency channel on which the link is established become congested, it is conceivable to change the bandwidth used by the link to narrow it. The operational parameters are changed in two ways: the communication device 102 determines new operational parameters and changes them, or the operational parameters are changed based on new operational parameters notified by the other device (communication device 103). When new operational parameters are notified by the other device, the operational parameter change unit 301 changes the operational parameters based on the operational parameters acquired by the operational parameter acquisition unit 302, which will be described later.

[0032] The operational parameter acquisition unit 302 is a block that acquires operational parameters contained in a MAC frame received from a partner device (communication device 103). In this embodiment, the operational parameters are contained in the header portion of the MAC frame.

[0033] The link selection unit 303 is a block that determines the link to be used when notifying the operation parameters when multiple links are established with the other device (communication device 103). The method of determining the link to be used for notifying the operation parameters will be described in detail later with reference to FIG.

[0034] The power save state management unit 304 is a block that manages whether to put a link in multi-link communication established with a partner device (communication device 103) into a power save state. Putting a link into a power save state refers to transitioning to a state in which communication using the link is not performed. Here, not performing communication refers to not communicating data frames. In addition, communication of management frames may also be prevented. If the communication device 102 has a communication unit 206 for each link, the supply of power to the communication unit 206 corresponding to the link transitioning to the power save state may be temporarily stopped or reduced. In this embodiment, a state in which a link is in communication, as opposed to the power save state, is called a wakeup state. If a communication unit 206 is provided for each link, the power supplied to the communication unit 206 corresponding to a link in the power save state is lower than the power supplied to the communication unit 206 corresponding to a link in the wakeup state. Furthermore, the communication unit 206 corresponding to a link in the power save state consumes less power than the communication unit 206 corresponding to a link in the wakeup state. Based on a MAC frame indicating a power save state received from a partner device (communication device 103), communication device 102 puts the link indicated in the received MAC frame into a power save state or a wakeup state. Alternatively, communication device 102 may put the link into a power save state or a wakeup state in response to an instruction from a user. Furthermore, communication device 102 may put the link into a power save state or a wakeup state based on the state of data communication with partner device 103. For example, when the amount of data to be transmitted to communication device 103 is lower than a predetermined threshold, communication device 102 transitions some of the multiple links established with communication device 103 into a power save state. On the other hand, when the amount of data to be transmitted to communication device 103 is higher than a predetermined threshold, communication device 102 transitions the link with communication device 103 that was in a power save state to a wakeup state.Alternatively, the communication device 102 transitions another link to the communication device 103 that was in a power save state to a wakeup state based on a decrease in the throughput of the link that was used for data communication with the communication device 103. In this case, the communication device 102 may transition the original link that was used for data communication from the wakeup state to the power save state.

[0035] The MAC frame generation unit 305 is a block that generates a MAC frame that includes information for notifying the other device (communication device 103) of the operational parameters changed by the operational parameter change unit 301. The MAC frames generated by the MAC frame generation unit 305 are various management frames such as a Beacon frame and a Probe Response frame. In addition to or instead of these, a data frame or the like may be generated. The information for notifying the operational parameters contained in the MAC frame will be described in detail later with reference to FIGS. 5 and 7. The MAC frame generation unit 305 may also generate a MAC frame that does not include information for notifying the operational parameters.

[0036] The data transmitter / receiver 306 transmits wireless frames including the MAC frames generated by the MAC frame generator 305 and receives wireless frames from the other device (communication device 103).

[0037] The communication device 103 has the same functional configuration as the communication device 102 .

[0038] FIG. 4 is a sequence diagram showing an example of processing executed when the communication device 102 and the communication device 103 change the operation parameters of the link.

[0039] In this embodiment, communication devices 102 and 103 establish two links to perform multi-link communication. Link 1 is a link using a first frequency channel (e.g., channel 1 in the 2.4 GHz band), and link 2 is a link using a second frequency channel (e.g., channel 36 in the 5 GHz band).

[0040] The processing of this sequence is started in response to the power-on of each of the communication devices 102 and 103. Alternatively, at least one of the communication devices 102 and 103 may start the processing in response to an instruction to start multilink communication from a user or an application. Alternatively, at least one of the communication devices 102 and 103 may start the processing in response to the amount of data to be communicated with the other device reaching or exceeding a predetermined threshold.

[0041] First, the communication device 102 and the communication device 103 establish link 1 on the first frequency channel by performing the process of S401. More specifically, the communication device 103 transmits an Authentication Request frame for authentication, and in response to that, the communication device 102 transmits an Authentication Response frame. Thereafter, the communication device 103 transmits an Association Request frame for connection, and in response to that, the communication device 102 transmits an Association Response frame. The Association Request frame transmitted by the communication device 103 includes information indicating link 1, such as information indicating the first frequency channel. In addition to or instead of the information indicating the first frequency channel, information indicating the BSSID of the wireless network established by the communication device 102 on the first frequency channel may be included. In addition to exchanging these frames, in S401, a 4-way Handshake process may be performed to generate an encryption key for data communication. Next, the communication device 102 and the communication device 103 establish link 2 on the second frequency channel by performing the process of S402. The specific processing of S402 is the same as that of S401. The Association Request frame transmitted by the communication device 103 in S402 includes, for example, information indicating the second frequency channel as information indicating link 2. In addition to or instead of the information indicating the second frequency channel, information indicating the BSSID of the wireless network established by the communication device 102 on the second frequency channel may be included. The communication devices 102 and 103 may establish both link 1 and link 2 by performing the process of S401. In this case, the communication device 103 includes information indicating both link 1 and link 2 in the Association Request frame sent in S401. Also, the process of S402 is omitted.

[0042] Before performing the process of S401, the communication devices 102 and 103 may exchange capability information related to multi-link communication by transmitting and receiving Beacon frames and Probe Request / Response frames.

[0043] After establishing multiple links, the communication device 103 transmits a QoS Null frame with the Power Management bit set to 1 to the communication device 102 via link 2 in S403. As a result, the communication device 103 notifies the communication device 102 that link 2 will be transitioned to the power save state. Thereafter, the communication device 103 transitions link 2 to the power save state in S404. Note that in this embodiment, the link that transmitted the QoS Null frame is transitioned to the power save state, but this is not limited to this. The communication device 103 may transmit a QoS Null frame including information indicating link 2 via link 1, and then transition link 2 to the power save state. In this case, the communication device 103 does not transition link 1, which transmitted the QoS Null frame, to the power save state. Note that the communication device 103 includes an identifier in the QoS Null frame, as information indicating link 2, that enables link 2 to be distinguished from other links. Additionally or alternatively, the communication device 103 may include information indicating the BSSID of the wireless network in which the link 2 is established, or may include information indicating the second frequency channel.

[0044] Thereafter, in S405, the communication device 102 changes the operation parameters of link 2. The change in the operation parameters is, for example, a change in the bandwidth available for communication on link 2. In addition to or instead of this, the MCS available for communication on link 2 may be changed. MCS is an abbreviation for Modulation and Coding Scheme, and is information indicating a combination of a modulation scheme and a coding rate used in communication. Note that when the operation parameters of link 2 are changed, it is sufficient that at least one of the modulation scheme and the coding rate is changed. Alternatively, as a change in the operation parameters, when the communication devices 102 and 103 are performing MIMO communication on link 2, the number of spatial streams used in the MIMO communication may be changed, or the MIMO communication may be terminated. Alternatively, the MIMO communication on link 2 may be started. Furthermore, a link in a power save state may be transitioned to a wakeup state.

[0045] When the communication device 102 changes the operation parameters of link 2, in S406 it transmits a Beacon frame including the changed operation parameters and the identifier of link 2 to the communication device 103 via link 1. This allows the communication device 102 to notify the communication device 103 of the changed operation parameters of link 2. The identifier of link 2 is information that can uniquely identify link 2 from other links. Alternatively, the BSSID of the wireless network in which link 2 is established may be included in the Beacon frame as the identifier of link 2. In this embodiment, a Beacon frame is used to notify of changes in operation parameters, but this is not limited to this, and the communication device 102 may also use a Probe Response frame or a data frame. Details of the frame formats used when notifying of changed operation parameters will be described later with reference to FIGS. 5 and 7.

[0046] When the communication device 103 receives a Beacon frame notifying a change in the operation parameters of link 2, it changes the operation parameters of link 2 in S407. In this sequence, it is assumed that the communication device 103 has been notified of the new bandwidth to be used in link 2 as the changed operation parameters. In this case, in this step, the communication device 103 changes the information related to the bandwidth among the operation parameters of link 2 that it holds.

[0047] Next, in S408, the communication device 103 cancels the power save state of link 2 and transitions to the wakeup state, thereby transitioning the communication device 103 from a state in which communication via link 2 cannot be performed to a state in which communication via link 2 can be performed.

[0048] In this embodiment, the communication device 103 transitions link 2 to the wakeup state in S408 even if it is not notified in the Beacon frame received in S406 that the link in the power save state will be transitioned to the wakeup state. This is not limiting, and the communication device 103 may or may not perform the process of S408 based on whether it has been notified of the transition to the wakeup state by the communication device 102. In other words, the communication device 103 may execute the process of S408 if it has been notified of the transition of link 2 to the wakeup state by the communication device 102, and may skip the process of S408 if it has not been notified of the transition of link 2 to the wakeup state by the communication device 102.

[0049] When the communication device 103 transitions link 2 to the wakeup state, in S409 it transmits a QoS Null frame in which the Power Management bit is set to 0 to the communication device 102. This allows the communication device 103 to notify the communication device 102 that it has transitioned link 2 to the wakeup state.

[0050] Next, in S410, the communication device 103 uses the new operational parameters to transmit a data frame via link 2, which has entered the wakeup state. In addition to or instead of transmitting a data frame from the communication device 103, the communication device 102 may also transmit a data frame via link 2 using the new operational parameters.

[0051] As shown in FIG. 4, when multiple links are established between communication devices 102 and 103 and the operational parameters of one of the links are changed, the changed operational parameters can be notified more quickly by notifying the changed operational parameters via another link.

[0052] Furthermore, if the link whose operational parameters have been changed is in a power save state, the changed operational parameters can be notified via another link, so that the changed operational parameters can be notified while the link remains in a power save state. This allows the changed operational parameters to be received without performing processing such as periodically transitioning a link in a power save state to a wakeup state, thereby improving the power saving performance of the communication device 103.

[0053] Fig. 5 is a diagram showing an example of a frame format including operation parameters of a predetermined link. The Control ID field 501 and Control Information field 502 shown in Fig. 5 are included in the HT Control field in the MAC header. HT stands for High Throughput. Alternatively, similar information may be included in the MAC frame body. This information may be included in a Beacon frame, a Probe Response frame, or a data frame. The operation parameters of the link are included in the Control Information field 502. The Control ID field 501 and Control Information field 502 are arranged in the MAC frame so that they are transmitted and received in order from the Control ID field 501.

[0054] The Control ID field 501 contains information indicating the type of information contained in the Control Information field 502. Information corresponding to the value contained in the Control ID field 501 is contained in the Control Information field 502. In other words, when the Control ID field 501 changes, the information contained in the Control Information field 502 also changes. In this embodiment, the Control ID field 501 contains a value indicating that the Control Information field 502 contains operational parameters.

[0055] The Control Information field 502 includes the following fields: Link ID 520, Rx NSS 521, Channel Width 522, and UL MU Disable 523. The Control Information field 502 further includes the following fields: Tx NSTS 524 and ER SU Disable 525. In addition to these, the Control Information field 502 includes the following fields: DL MU-MIMO Resound Recommendation 526 and UL MU Data Disable 527.

[0056] UL stands for Uplink and refers to data transmission from a STA to an AP, while DL stands for Downlink and refers to data transmission from an AP to a STA.

[0057] Although the fields 520 to 527 are arranged in the Control Information field 502 so as to be transmitted and received in order starting from 520, the order of the fields is not limited to this. Any field may be arranged so as to be transmitted and received immediately before or after another field. Furthermore, at least one of the fields 520 to 527 may be omitted from the Control Information field 502.

[0058] Link ID 520 is a field that includes identification information for identifying a link whose operational parameters are to be changed. Specifically, the link identification information is an ID assigned to the link when the communication devices 102 and 103 establish a link for multi-link communication. Based on the link ID, the communication devices 102 and 103 can uniquely identify a specific link from among the multiple links established between them.

[0059] In addition to or instead of Link ID 520, a field containing identification information for identifying a wireless network in which a link whose operational parameters are to be changed is established may be included. Specifically, the identification information for identifying a wireless network is the BSSID of the wireless network. Note that a hash value of the BSSID may be included instead of the BSSID.

[0060] Rx NSS 521 is a field that includes information indicating the number of MIMO spatial streams that can be used when the communication device 102 receives data.

[0061] Channel Width 522 is a field that contains information indicating the bandwidth that the communication device 102 can use to send and receive data.

[0062] UL MU Disable 523 is a field containing information indicating the type of frame that communication device 102 can transmit in UL MU communication. Specifically, it indicates the type of frame that can be transmitted in combination with UL MU Data Disable 527, which will be described later. Details will be described later. Note that in addition to or instead of this field, Control Information field 502 may include a field containing information indicating the type of frame that communication device 102 can communicate in DL MU communication.

[0063] The Tx NSTS 524 is a field that includes information indicating the number of MIMO spatial streams that can be used when the communication device 102 transmits data.

[0064] ER SU Disable 525 is a field that includes information indicating whether the communication device 102 supports reception of frames in a predetermined format for extending communication distance.

[0065] The DL MU-MIMO Resound Recommendation 526 is a field containing information for requesting an increase in the frequency of sounding processing for acquiring the channel state used by the communication device 102 for MIMO communication.

[0066] UL MU Data Disable 527 is a field including information indicating whether or not data communication of an UL MU can be performed by communication device 102. Note that, in addition to or instead of this field, Control Information field 502 may include a field including information indicating whether or not data communication of a DL MU can be performed by communication device 102.

[0067] The frame format shown in FIG. 5 indicates the types of frames that the communication device 102 can transmit in UL MU communication by combining UL MU Disable 523 and UL MU Data Disable 527. Specifically, when both fields contain the value 0, this indicates that the communication device 102 can transmit both data frames and management frames in UL MU communication. When UL MU Disable 523 contains 0 and UL MU Data Disable 527 contains 1, this indicates that the communication device 102 can only transmit management frames in UL MU communication. In this case, the communication device 102 cannot transmit data frames in UL MU communication. Furthermore, when UL MU Disable 523 contains 1, this indicates that the communication device 102 cannot transmit either data frames or management frames in UL MU communication. In this case, UL MU Data Disable 527 also contains 1.

[0068] In this embodiment, the communication device 102 indicates the type of frames that can be transmitted in UL MU communication by combining UL MU Disable 523 and UL MU Data Disable 527, but this is not limited to this. The communication device 102 may indicate the type of frames that can be transmitted in DL MU communication in addition to or instead of UL MU communication by including a similar field for DL ​​MU communication in the Control Information field 502.

[0069] The communication device 102 can notify the communication device 103 of the changed operational parameters by transmitting a Beacon frame including the frame format shown in Fig. 5 to the communication device 103. Note that the communication device 102 may transmit a Probe Response frame or a data frame including the frame format shown in Fig. 5 instead of a Beacon frame.

[0070] In addition to or instead of at least one of the fields shown in Fig. 5, the communication device 102 may transmit a field including information indicating whether or not to transition the link from a power save state to a wakeup state. In addition to or instead of at least one of the fields shown in Fig. 5, the communication device 102 may transmit a field including information indicating an MCS that the communication device 102 can use in communication. In addition to or instead of at least one of the fields shown in Fig. 5, the communication device 102 may transmit at least one of a field indicating a coding rate that the communication device 102 can use in communication and a field indicating a modulation method, instead of a field indicating an MCS.

[0071] Fig. 5 shows a frame format that can notify the operation parameters of one link, while Fig. 7 shows an example of a frame format that can notify the operation parameters of multiple links.

[0072] The Control ID field 701 and Control Information field 702 shown in Fig. 7 are included in the HT Control field in the MAC header. Alternatively, similar information may be included in the MAC frame body. Note that this information may be included in a Beacon frame, a Probe Response frame, or a data frame. The Control ID field 701 and Control Information field 702 are arranged in the MAC frame so that they are transmitted and received in order starting from the Control ID field 701.

[0073] The Control ID field 701 is the same as the Control ID field 501 in Fig. 5. Note that, when distinguishing between a notification of operation parameters for one link and a notification of operation parameters for multiple links, a value different from that in the Control ID field 501 is set in the Control ID field 701.

[0074] The Control Information field 702 includes information indicating the operation parameters of multiple links. As shown in 710, the operation parameters corresponding to one link are indicated by a set of a Link ID field 711 and an OM (Operating Mode) Control field 712. The Control Information field 702 can indicate the operation parameters of multiple links by including multiple sets of the fields shown in 710.

[0075] The Link ID field 711 is the same as the Link ID 520 in FIG.

[0076] The OM Control field 712 contains information indicating the operational parameters of the link indicated by the Link ID field 711 arranged to be transmitted and received immediately before. Fields 721 to 727 contained in the OM Control field 712 are the same as fields 521 to 527 in FIG.

[0077] In addition to or instead of at least one of the fields shown in Fig. 7, the communication device 102 may transmit a field including information indicating whether or not to transition the link from a power save state to a wakeup state. In addition to or instead of at least one of the fields shown in Fig. 7, the communication device 102 may transmit a field including information indicating the MCS used in communication by the communication device 102. In addition to or instead of the field indicating the MCS, the communication device 102 may transmit at least one of a field indicating the coding rate used in communication by the communication device 102 and a field indicating the modulation method.

[0078] By using the frame format shown in FIG. 7, the communication device 102 can transmit changed operational parameters for multiple links in one MAC frame.

[0079] The communication device 102 may indicate the operational parameters of both Link 1 and Link 2 in Fig. 4 using the frame format shown in Fig. 7. In this case, the communication device 102 transmits a Beacon including the operational parameters of both Link 1 and Link 2 via a link (Link 3) between the communication device 102 and the communication device 103 that is different from Link 1 and Link 2.

[0080] FIG. 6 is a flowchart showing the processing that is executed by the control unit 202 reading and executing a computer program stored in the storage unit 201 when the communication device 102 changes the operational parameters of a link.

[0081] This flowchart starts in response to a decision made by communication device 102 to change the operational parameters of a predetermined link with communication device 103 after communication device 102 has established multiple links with communication device 103. The change in the operational parameters may be decided by an application running on communication device 102, or may be decided based on a user operation that instructs a change in the operational parameters.

[0082] Alternatively, the communication device 102 may determine to change the operational parameters of a link in response to a predetermined number of retransmissions occurring in communication with the communication device 103 via the link. The threshold for the number of retransmissions may be set by a user or may be set in advance in the communication device 102. Alternatively, the communication device 102 may determine to change the operational parameters of the link in response to a throughput of communication with the communication device 103 via the link falling below a predetermined threshold. The throughput threshold may be set by a user or may be set in advance in the communication device 102. Alternatively, the communication device 102 may determine to change the operational parameters of the link in response to a signal-to-noise ratio (SNR) of communication with the communication device 103 via the link falling below a predetermined threshold. The signal-to-noise ratio threshold may be set by a user or may be set in advance in the communication device 102. Alternatively, the communication device 102 may determine to change the operation parameters of a predetermined link when the carrier-to-noise ratio (CNR) of communication with the communication device 103 via the predetermined link becomes equal to or less than a predetermined threshold. The carrier-to-noise ratio threshold may be set by a user or may be set in advance in the communication device 102. Alternatively, the communication device 102 may determine to change the operation parameters of the predetermined link when the received signal strength indicator (RSSI) of a signal received from the communication device 103 via the predetermined link becomes equal to or less than a predetermined threshold. RSSI stands for Received Signal Strength Indication. The RSSI threshold may be set by a user or may be set in advance in the communication device 102. Alternatively, the communication device 102 may measure the percentage of times the predetermined link with the communication device 103 becomes busy during a predetermined period, and determine to change the operation parameters of the link when the percentage becomes equal to or greater than a predetermined value. The threshold for the percentage at which the link becomes busy may be set by the user or may be preset in the communication device 102 .The communication device 102 may initiate this flow based on at least one of these conditions, or may combine two or more conditions and initiate this flow if all of the combined conditions are met.

[0083] First, the communication device 102 changes the operation parameters of a predetermined link (S601). This process is similar to S405 in FIG.

[0084] Next, the communication device 102 determines whether the link whose operational parameters have been changed in S601 is in a power save state (S602). If the link is in a power save state, the communication device 102 determines Yes in this step and performs processing in S603. On the other hand, if the link is not in a power save state, that is, if the link is in a wakeup state, the communication device 102 determines No in this step and performs processing in S604.

[0085] Note that the determination in this step is not limited to whether the link is in a power save state. In addition to or instead of this, it may be determined whether the throughput of the link in question is lower than a predetermined threshold. If the throughput of the link in question is lower than the predetermined threshold, the communication device 102 determines Yes in this step, and if the throughput is higher than the predetermined threshold, it determines No in this step. Alternatively, the communication device 102 may determine whether the signal-to-noise ratio (SNR) of the link in question is lower than a predetermined threshold. If the signal-to-noise ratio of the link in question is lower than the predetermined threshold, the communication device 102 determines Yes in this step, and if the signal-to-noise ratio is higher than the predetermined threshold, it determines No in this step. Alternatively, the communication device 102 may determine whether the carrier-to-noise ratio (CNR) of the link in question is lower than a predetermined threshold. The communication device 102 determines "Yes" in this step if the carrier-to-noise ratio of the link in question is lower than a predetermined threshold, and determines "No" in this step if the carrier-to-noise ratio is higher than the predetermined threshold. Alternatively, the communication device 102 may determine whether the RSSI of a signal received from the communication device 103 via the link in question is lower than a predetermined threshold. The communication device 102 determines "Yes" in this step if the RSSI of a signal received via the link in question is lower than a predetermined threshold, and determines "No" in this step if the RSSI is higher than the predetermined threshold. Alternatively, the communication device 102 may determine whether the rate at which the link in question is busy per predetermined period is higher than a predetermined threshold. The communication device 102 determines "Yes" in this step if the rate at which the link in question is busy is higher than a predetermined threshold, and determines "No" in this step if the rate at which the link is busy is lower than the predetermined threshold. The communication device 102 performs the determination in this step based on at least one of these conditions. Alternatively, the communication device 102 may combine two or more conditions and determine Yes in this step if all of the combined conditions are Yes, and determine No in this step if one or more conditions are No.Alternatively, the communication device 102 may determine this step as Yes if at least one of the multiple conditions is Yes, and may determine this step as No if all of the conditions are No.

[0086] If the communication device 102 determines Yes in S602, it selects a link other than the link whose operational parameters have been changed as the link for notifying the changed operational parameters (S603). For example, if the link whose operational parameters have been changed is in a power save state, the communication device 102 cannot notify the operational parameters via that link, and therefore selects a link other than the communication device 103 as the link for notifying the operational parameters. Alternatively, for example, if the throughput of the link whose operational parameters have been changed is lower than a predetermined threshold, even if the communication device 102 notifies the changed operational parameters via that link, the communication device 103 may not be able to receive them immediately. Therefore, by selecting a link other than the communication device 103 as the link for notifying the changed operational parameters, the communication device 102 can notify the communication device 103 of the new operational parameters more quickly.

[0087] On the other hand, if the communication device 102 determines No in S602, it selects the link whose operational parameters have been changed as the link to which the changed operational parameters will be notified (S604).

[0088] The communication device 102 sets the identification information of the link whose operational parameters have been changed in S601 and the changed operational parameters in the MAC frame (S605). Specifically, the communication device 102 generates a MAC frame that includes the frame shown in Fig. 5 or 7, which includes information about the link whose operational parameters have been changed in S601.

[0089] The communication device 102 transmits the MAC frame in which the information was set in S605 to the communication device 103 via the link selected in S603 or S604 (S606), and ends the processing of this flow.

[0090] 6, when communication device 102 changes the operational parameters of a link, it can quickly notify communication device 103, the other device, of the new operational parameters. Also, if the link whose operational parameters have been changed is in a power save state, it can notify communication device 103 of the operational parameters by notifying the new operational parameters via another link.

[0091] In this embodiment, the communication device 102 changes its own operational parameters and then notifies the communication device 103 of the changed operational parameters. However, this is not limited to this, and the communication device 102 may notify the operational parameters before changing them. Specifically, the communication device 102 may perform the process of S406 in FIG. 4 and then the process of S405. Furthermore, when the communication device 102 starts the process of the flow in FIG. 6, it may start from the process of S602 instead of S601. In this case, the communication device 102 performs the process of S601 after S606, and ends the process of the flow in FIG. 6.

[0092] Furthermore, in this embodiment, the communication device 102 notifies the changed operational parameters only via a link different from the link whose operational parameters have been changed in S603, but this is not limiting, and the notification may also be made on the link whose operational parameters have been changed. Specifically, in S606 of Fig. 6, the communication device 102 may notify the operational parameters via the link whose operational parameters have been changed, in addition to notifying the operational parameters via a link different from the link whose operational parameters have been changed. Note that when the link whose operational parameters have been changed is in a power save state, the communication device 102 notifies only via the link whose operational parameters have been changed.

[0093] Furthermore, in the present embodiment, the communication device 102 changes the operational parameters of the link based on, for example, a decrease in throughput of the link with the communication device 103 or a deterioration in the signal-to-noise ratio. However, this is not limited thereto, and the communication device 102 may decide to change the operational parameters of a predetermined link with the communication device 103 based on, for example, an increase in the throughput of the link or an improvement in the signal-to-noise ratio. Specifically, the communication device 102 may decide to change the operational parameters of the link in response to the throughput of the predetermined link with the communication device 103 becoming equal to or greater than a predetermined threshold. Additionally or alternatively, the communication device 102 may decide to change the operational parameters of the link in response to the signal-to-noise ratio (SNR) of the predetermined link with the communication device 103 becoming equal to or greater than a predetermined threshold. Furthermore, the communication device 102 may decide to change the operational parameters of the link in response to the carrier-to-noise ratio (CNR) of the predetermined link with the communication device 103 becoming equal to or greater than a predetermined threshold. Furthermore, the communication device 102 may determine to change the operational parameters of a given link when the RSSI of a signal received from the communication device 103 via that link exceeds a predetermined threshold. The communication device 102 may also determine to change the operational parameters of that link when the rate at which the link is busy per predetermined time period falls below a predetermined value. In this case, when the communication device 102 changes the operational parameters of the link in S601 of FIG. 6 , the communication device 102 changes the operational parameters to increase the data communication speed. For example, the communication device 102 changes the operational parameters to perform MU communication or to use a higher coding rate. In this case, too, a decrease in the throughput of the link whose operational parameters have been changed can be prevented by notifying the changed operational parameters via a link different from the link whose operational parameters have been changed.

[0094] Furthermore, in this embodiment, the communication device 102 transmits a MAC frame including the changed operational parameters to the communication device 103. In this case, the communication device 102 may transmit the MAC frame including the changed operational parameters a predetermined number of times. By transmitting the MAC frame including the changed operational parameters multiple times, the communication device 102 can reduce the possibility that the changed operational parameters will not be notified to the communication device 103. Note that the number of times that the communication device 102 transmits the MAC frame including the changed operational parameters may be set by the user or may be preset in the communication device 102.

[0095] Furthermore, the communication device 102 may continue to transmit MAC frames including the changed operational parameters for a predetermined period of time after the first transmission of a MAC frame including the changed operational parameters. The period during which the communication device 102 transmits MAC frames including the changed operational parameters may be set by a user or may be preset in the communication device 102.

[0096] For example, when the communication device 102 transmits a Beacon during a predetermined period after performing the process of S606 in Fig. 6, the communication device 102 transmits a Beacon including the changed operation parameters. When the predetermined period ends, the communication device 102 transmits a Beacon that does not include the changed operation parameters.

[0097] Note that a Beacon that does not include the updated operational parameters must include at least a Time Stamp, Beacon interval, and Capability Information. In addition to these, a Beacon must also include an SSID, Supported Rates, and BSS Membership Selectors.

[0098] The Timestamp contains information indicating the value of the TSF (Timing Synchronization Function) timer of the device transmitting the MAC frame.

[0099] Beacon interval includes information indicating the interval at which a beacon is transmitted by a MAC frame transmitting device.

[0100] The Capability Information includes information indicating whether the MAC frame transmitting device can execute a Point Coordination Function (PCF) or not, and whether the MAC frame transmitting device requires encryption for data communication.

[0101] The SSID contains information indicating the ESS or IBSS identifier of the device transmitting the MAC frame. ESS stands for Extended Service Set, and IBSS stands for Independent Basic Service Set. The ESS identifier includes the ESSID, which is the AP identification name. Generally, the ESSID includes the SSID.

[0102] The Supported Rates and BSS Membership Selectors includes information indicating the wireless transmission rates supported by the beacon transmitting device.

[0103] The Beacon containing the changed operational parameters includes the information shown in Figure 5 in addition to the above required information.

[0104] Similarly, for example, when the communication device 102 transmits a probe response within a predetermined period after performing the process of S606 in Fig. 6, the communication device 102 transmits a probe response that includes the changed operational parameters. When the predetermined period ends, the communication device 102 transmits a probe response that does not include the changed operational parameters. A probe response that does not include the changed operational parameters must include at least a time stamp, beacon interval, capability information, and SSID. Supported rates and BSS membership selectors may or may not be included in the probe response.

[0105] The Probe Response containing the changed operational parameters includes the information shown in Figure 5 in addition to the above required information.

[0106] Also, for example, if communication device 102 transmits a data frame including changed operational parameters at S606 in FIG. 6, communication device 102 may be configured to periodically transmit data frames including changed operational parameters for a predetermined period of time.

[0107] At least a part or all of the flowchart of the communication device 103 shown in FIG. 6 may be realized by hardware. When realized by hardware, for example, a specific compiler may be used to generate a dedicated circuit on an FPGA from a computer program for realizing each step, and this may be used. FPGA stands for Field Programmable Gate Array. Alternatively, a gate array circuit may be formed in the same manner as an FPGA and realized as hardware. Alternatively, it may be realized by an ASIC (Application Specific Integrated Circuit).

[0108] 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]

[0109] 101 Network 102 Communication equipment (AP) 103 Communication equipment (STA) 104 First Link 105 Second Link

Claims

1. A communication device, establishing means for establishing a first link via a first frequency channel and a second link via a second frequency channel by communicating an association request frame and an association response frame with another communication device using the first frequency channel; a notification means for notifying the other communication device of information related to a change in power management of the second link via the first link; A communication device comprising:

2. The notifying means notifies the other communication device of information related to a change in power management of the second link by transmitting a MAC frame conforming to the IEEE 802.11 series standard to the other communication device via the first link.

2. The communication device according to claim 1.

3. The notification means notifies the other communication device of information related to a change in power management of the second link by transmitting a beacon frame via the first link.

3. The communication device according to claim 1 or 2.

4. The notification means notifies the other communication device of first information including information related to a change in power management of the second link and identification information corresponding to the second link.

4. The communication device according to claim 1, wherein the communication device is a communication device having a plurality of communication ports.

5. The identification information is a Link ID.

5. The communication device according to claim 4.

6. The notification means periodically notifies the first link of the beacon frame including information related to a change in power management of the second link for a first period.

4. The communication device according to claim 3.

7. When the second link is changed from a second state to a first state in which power consumption is higher than that of the second state, the notification means notifies the other communication device of information related to the change in power management of the second link via the first link.

7. The communication device according to claim 1, wherein the communication device is a communication device having a plurality of communication ports.

8. The information relating to changes in Power Management of the second link is:

8. The communication device according to claim 1, wherein the information indicates whether or not the second link is to be transitioned from a power save state to a wakeup state.

9. A method for controlling a communication device, comprising: an establishing step of establishing a first link via a first frequency channel and a second link via a second frequency channel by communicating an association request frame and an association response frame with another communication device using the first frequency channel; a notification step of notifying the other communication device of information related to a change in power management of the second link via the first link; A method for controlling a communication device, comprising:

10. A program for causing a computer to function as the communication device control method according to claim 9.

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