Communication device, control method, and program

Abstract

A communication device according to the present invention receives a radio frame including information on a target wake time (TWT) of a first network constructed by a first communication device different from the communication device. The communication device transmits a predetermined frame including a predetermined element including information for identifying the first communication device and information related to the TWT of the first network.

Description

Communication device, control method, and program

[0001] The present invention relates to a communication device that performs wireless communication, a control method for the communication device, and a program.

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard series is known as the main communication standard for WLANs (Wireless Local Area Networks), and includes standards such as IEEE 802.11a / b / g / n / ac / ax.

[0003] The IEEE802.11ax standard described in Patent Document 1 discloses that wireless communication is performed using Orthogonal Frequency-Division Multiple Access (OFDMA). The IEEE802.11ax standard achieves high peak throughput by performing wireless communication using OFDMA. The IEEE802.11ax standard also introduces a power-saving technology called Target Wake Time (TWT). The IEEE802.11ax standard uses TWT to negotiate the interval between a Doze state in which an AP (Access Point) and a Station (STA) do not transmit or receive frames, and an Awake state in which frames are transmitted or received, thereby enabling the AP to control the timing of communication between each STA. This reduces the time that the STA is in an awake state when it is not communicating, thereby reducing power consumption.

[0004] Furthermore, the IEEE 802.11be standard, a successor to IEEE 802.11ax, is currently being developed. A new function of the IEEE 802.11be standard is being considered, which is multi-link communication, in which an AP and a STA establish multiple parallel links via multiple different frequency channels to communicate. For example, Patent Document 2 describes a mechanism for establishing multiple links for multi-link communication. Furthermore, the IEEE 802.11be standard is also being considered for low-latency communication using the TWT described above.

[0005] JP 2018-50133 A JP 2021-103805 A

[0006] In the IEEE802.11be standard, R-TWT (Restricted TWT) is under consideration.

[0007] R-TWT is a mechanism in which a period called a Service Period (SP) is set in a network (BSS) during which only specified terminals within the network can communicate, and during that period, only the specified specified terminals are in an Awake state (a state in which they can communicate) and can communicate. By providing an SP in this way, terminals that are permitted to communicate in the SP can have exclusive access rights to the communication channel. On the other hand, terminals that are not permitted to communicate in the SP can save power by, for example, entering a Doze state (a state in which they cannot communicate) during that period.

[0008] However, the SP schedule is set for each network, and the SP schedule is not shared with other networks (OBSSs). Therefore, a terminal that does not know the schedule of an SP of a different network may communicate during an SP of a different network. This may cause communication of a terminal that is permitted to communicate during an SP to be hindered by communication of a terminal that does not know the SP. This may hinder the realization of low-latency communication using an SP.

[0009] Therefore, one of the objects of the present invention is to provide a specific mechanism for sharing information about TWTs in different networks.

[0010] In order to achieve the above object, a communication device according to one aspect of the present invention is a communication device, comprising: a receiving means for receiving a wireless frame including information regarding a Target Wake Time (TWT) of a first network established by a first communication device different from the communication device; and a transmitting means for transmitting a predetermined frame including a predetermined element including information identifying the first communication device and information regarding the TWT of the first network.

[0011] One aspect of the present invention allows for the sharing of information about TWTs in different networks.

[0012] 1 is a diagram showing an example of a network configuration. 2 is a diagram showing an example of a hardware configuration of a communication device. 3 is a diagram showing an example of a functional configuration of a communication device. 4 is a diagram showing an example of a flowchart for setting TWT information. 5 is a diagram showing an example of a frame configuration of a Reduced Neighbor Report Element. 6 is a diagram showing an example of a Restricted TWT Schedule Info Subfield Value. 7 is a diagram showing an example of a flowchart for processing to share TWT information. 8 is a diagram showing an example of a frame configuration of a Neighbor Report Element. 9 is a diagram showing an example of a frame configuration of a TWT Element.

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0014] <First Embodiment> (Network Configuration) Fig. 1 shows an example of a network configuration according to this embodiment. This embodiment is configured with a network 101, which is a first network, and a network 104, which is a second network different from the first network. In this embodiment, a STA MLD 103, which operates as a terminal, participates in the network 101 established by an AP MLD 102 operating as a base station. Furthermore, a STA MLD 106, which operates as a terminal station, participates in the network 104 established by an AP MLD 105 operating as a base station. Note that AP MLD is an abbreviation for Access Point Multi-Link Device, and STA MLD is an abbreviation for Station Multi-Link Device. STA MLD is also referred to as non-AP MLD. An MLD is a communication device equipped with multiple STAs (or APs). By having multiple STAs, an MLD can establish multiple links with opposing MLDs in parallel via different frequency channels. Multi-link communication can also be performed via the established multiple links. Network 101 is a network identified by a first BSS (Basic Service Set), and network 104 is a network identified by a second BSS (Basic Service Set). From the perspective of a terminal belonging to a certain network, such as AP MLD 102 or STA MLD 103, other networks different from the network to which the terminal belongs may also be called OBSSs (Overlapping Basic Service Sets).

[0015] In this embodiment, the AP MLD 102, the STA MLD 103, the AP MLD 105, and the STA MLD 106 are, for example, MLDs, but these communication devices do not have to be MLDs and may be the AP 102, the STA 103, the AP 105, and the STA 106, respectively.

[0016] Furthermore, each communication device (AP MLD 102, STA MLD 103, AP MLD 105, and STA MLD 106) is configured to be able to communicate wireless frames compliant with the IEEE 802.11bn standard, which is the successor to the IEEE 802.11be standard and targets a maximum transmission speed of 46.08 Gbps. Note that IEEE stands for Institute of Electrical and Electronics Engineers. The IEEE 802.11bn standard, the successor to IEEE 802.11be, has the following main features: highly reliable communication, low latency communication, and improved throughput during congestion. Another goal of 802.11bn is to reduce power consumption in APs. A wireless frame communicated under this successor standard is also called a UHR (Ultra High Reliability) PPDU, where PPDU stands for PLCP Protocol Data Unit and PLCP stands for Physical Layer Convergence Protocol.

[0017] The name UHR was chosen for convenience, taking into account the goals and key features of the successor standard, and may be renamed once the standard is fully developed. Similarly, the name IEEE 802.11bn may be renamed once the standard is fully developed. Note that this specification and the accompanying claims essentially apply to all successor standards to the 802.11be standard. Each communication device can communicate at frequencies in the 2.4 Hz, 3.6 GHz, 5 GHz, and 6 GHz bands, as well as the 45 GHz and 60 GHz bands known as millimeter waves. The frequency bands used by each communication device are not limited to these, and a different frequency band, such as the Sub-1 GHz band, may also be used. Each communication device can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, and 640 MHz. The bandwidth used by each communication device is not limited to this, and different bandwidths such as 240 MHz and 4 MHz may be used.

[0018] Furthermore, each communication device can perform OFDMA communication compliant with the IEEE 802.11ax / be / bn standard, thereby realizing multi-user (MU) communication, which multiplexes signals from multiple users. OFDMA stands for Orthogonal Frequency Division Multiple Access. In OFDMA communication, a portion of the resource unit of the divided frequency band is assigned to each STA so that they do not overlap, and the carrier waves of each STA are orthogonal. Therefore, an AP can communicate simultaneously with multiple STAs within a specified bandwidth. Furthermore, each communication device may support other communication standards such as Bluetooth (registered trademark), NFC, UWB, ZigBee, and MBOA in addition to the IEEE 802.11 series standards. UWB stands for Ultra Wide Band, MBOA stands for Multi Band OFDM Alliance, and NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, etc. It may also be compatible with wired communication standards such as wired LAN.

[0019] Specific examples of the AP MLD 102 and the AP MLD 105 include, but are not limited to, a wireless LAN router or a personal computer (PC), and any communication device capable of operating as an access point (AP). Each AP MLD may be an information processing device such as a wireless chip capable of performing wireless communication in accordance with the IEEE 802.11bn standard. Specific examples of the STA MLD 103 and the STA MLD 106 include, but are not limited to, a camera, a tablet, a smartphone, a PC, a mobile phone, a video camera, a headset, a network camera, a printer, a projector, and smart glasses. Each STA MLD may be an information processing device such as a wireless chip capable of performing wireless communication in accordance with the IEEE 802.11bn standard.

[0020] Furthermore, as an example of the network configuration of this embodiment, network 101, which consists of one AP MLD and one STA MLD, and network 104 are configured adjacent to each other, but the number of networks, APs, and STAs is not limited to this, and each may include multiple APs and STAs.

[0021] 2 shows an example of the hardware configuration of each communication device. Each communication device 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.

[0022] The storage unit 201 is configured with ROM and / or RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. RAM stands for Random Access Memory, and ROM stands for Read Only Memory. Note that the storage unit 201 may be a storage medium such as a non-volatile storage device, such as a hard disk or SSD (Solid State Drive), in addition to memories such as ROM and RAM.

[0023] The control unit 202 is configured with, for example, a processor such as a CPU or MPU, an ASIC (application-specific integrated circuit), a DSP (digital signal processor), an FPGA (field programmable gate array), etc. Here, CPU stands for Central Processing Unit, and MPU stands for Micro Processing Unit. The control unit 202 executes programs stored in the storage unit 201 and controls the entire device by operating hardware circuits such as the ASIC. Note that the control unit 202 may control the entire device in cooperation with the programs stored in the storage unit 201 and an OS (operating system).

[0024] The control unit 202 also controls the functional unit 203 to perform predetermined processes such as capturing images, printing, and projection. The functional unit 203 is hardware that enables the device to perform predetermined processes. For example, if the communication device is a camera such as a digital still camera or a smartphone equipped with a camera, the functional unit 203 is an imaging unit that captures images of the surroundings via a camera unit (not shown) included in the communication device. For example, if the communication device is a printer, the functional unit 203 is a printing unit that performs printing on a sheet such as paper based on print data obtained from the outside via wireless communication. For example, if the communication device is a projector or smart glasses, the functional unit 203 is a projection unit that performs projection of image data or video data obtained from the outside via wireless communication. In the case of smart glasses, the projection surface is the end user's retina, for example. The data processed by the functional unit 203 may be data stored in the storage unit 201 or data communicated with another AP or STA via the communication unit 206 (described later). Furthermore, a communication device such as the AP 101 can also provide a network storage function such as a network attached storage (NAS). This function is provided to other communication devices as a web service such as a network storage service. For example, a communication device such as an STA connects to a network storage service provided by an AP MLD or the like using a protocol such as SMB, FTP, or WebDAV. The communication device such as the STA then uploads files to the storage service or downloads files from the storage. This upload and download data communication is also realized by communicating UHR PPDUs between devices.

[0025] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes, for example, at least one of display on a screen, audio output by a speaker, and vibration output. Note that both the input unit 204 and the output unit 205 may be implemented by a single module, such as a touch panel. The output unit 205 functions as a display means for presenting information to the user. The input unit 204 also functions as a reception means for receiving user operations.

[0026] The communication unit 206 controls wireless communications compliant with the IEEE 802.11 series of standards and IP communications. In this embodiment, the communication unit 206 can execute communication control for transmitting and receiving UHR PPDUs, which are wireless frames of the UHR standard, and PPDUs conforming to earlier standards, in cooperation with the antenna 207. The antenna 207 is an antenna capable of transmitting and receiving signals in at least one frequency band of, for example, the sub-GHz band, the 2.4 GHz band, the 5 GHz band, the 6 GHz band, and the millimeter wave band.

[0027] If the communication device is compatible with the aforementioned NFC standard, Bluetooth standard, wired communication standard, or the like, the communication unit 206 may be configured to control wireless communication or wired communication in accordance with these communication standards.

[0028] (Functional Configuration of Communication Device) Next, FIG. 3 shows a block diagram illustrating an example of the functional configuration of each communication device in this embodiment. In this embodiment, each functional block is stored as a program in the storage unit 201, and the function is implemented by executing the program by the control unit 202. By executing the program, the control unit 202 realizes each function by controlling each piece of hardware and calculating and processing information. Note that some or all of the functional blocks may be implemented as hardware. In this case, some or all of the functional blocks may be configured by, for example, an ACIC (Application Specific Integrated Circuit).

[0029] In this embodiment, each communication device includes a TWT information acquisition unit 301 , a frame generation unit 302 , a frame transmission / reception unit 303 , a multi-link control unit 304 , and a UI control unit 305 .

[0030] The TWT information acquisition unit 301 acquires TWT information set in different networks from management frames such as Beacon frames, Probe Response frames, and Association Response frames from different networks.

[0031] The frame generation unit 302 generates a wireless frame to be transmitted via a frame transmission / reception unit (described later). In this embodiment, the frame generation unit 302 generates a frame for sharing the TWT information with other communication devices based on the TWT information of different networks acquired by the TWT information acquisition unit 301.

[0032] The frame transmitting / receiving unit 303 is configured to include an antenna and circuit for transmitting and receiving wireless frames (or signals) to and from other wireless communication devices, and a program for controlling them. The frame transmitting / receiving unit 303 executes wireless LAN communication control based on the frames generated by the frame generating unit 302 in accordance with the IEEE 802.11 standard series.

[0033] The multi-link control unit 304 controls processes related to link establishment, such as link establishment process for establishing one or more links used for wireless communication with the opposing MLD, communication start process, link addition / deletion process after link establishment, and communication termination process for deleting all links. The link establishment process mainly consists of authentication process, association process, and 4-Way-Hand-Shake (4WHS) process.

[0034] The UI control unit 305 is composed of hardware related to a user interface, such as a touch panel or buttons, for accepting user operations, and a program for controlling these. For example, the multilink control unit 304 selects a partner device to which a communication device will connect by accepting user operations via the UI control unit 305. The multilink control unit 304 also accepts user operations via the UI control unit 306, thereby selecting and determining the STAs provided in each communication device to be used when each communication device establishes a link. The UI control unit 306 may also have a function for displaying information to the user, such as audio output.

[0035] (TWT Information) Next, the TWT information will be described. In this embodiment, the Target Wake Time (TWT) information includes at least information related to a Service Period (SP). However, the TWT information is not limited to this and may further include other information related to the TWT. For example, the TWT information may be configured to include a Traffic Identifier (TID) indicating the type of data that can be transmitted in the SP, information related to a TWT group indicating a group of multiple STAs that share a common SP, etc.

[0036] The SP is set through coordination between the AP and the STA in the network, and indicates the period during which the STA is in an awake state (a state in which communication is possible). Generally, the STA is in a doze state (a state in which communication is not possible) outside the SP, but this is not limiting and the STA may be configured to communicate outside the SP. Within the SP, the STA is in an awake state and transmits and receives frames. On the other hand, outside the SP, the STA is in a doze state, which allows power saving. The TWT information is not limited to the above, and may be configured to include information included in the TWT parameter information described below. The information regarding the SP includes, for example, information regarding the start timing of the SP, information regarding the time from the start to the end of the SP, and information regarding the interval between the start timings of each SP.

[0037] (Setting of TWT Information) Next, a flowchart for setting TWT information in the AP MLD 102 and the STA MLD 103 of the network 101 will be described.

[0038] FIG. 4 illustrates an example of a flowchart in which the AP MLD 102 receives a TWT Request from the STA MLD 103 and sets TWT information by transmitting a TWT Response in response to the TWT Request.

[0039] 4 is started when the STA MLD 103 sets or updates TWT information. In this embodiment, the setting of TWT information at the time of initial link setup between the AP MLD 102 and the STA MLD 103 will be described.

[0040] In S401, the AP MLD 102 receives an Association Request frame including a TWT Request transmitted by the STA MLD 103 via the communication unit 206. Here, the TWT Request is information indicating that the STA MLD requests the AP MLD to set TWT information. The TWT Request includes TWT information such as information indicating whether the source STA supports TWT, an AID (Association Identifier), the start timing of the SP, the time from the start to the end of the SP, and information regarding the period and interval of the SP.

[0041] In S402, the AP MLD 102 transmits an Association Response frame including a TWT Response to the STA MLD 103 via the communication unit 206. The TWT Response is information indicating approval of setting information regarding the start time, end time, and period of the SP of the TWT Request received in S401 as TWT information. For example, the AP MLD 102 may be configured to indicate approval by including the same value as the TWT Request in the TWT Response. Furthermore, if the AP MLD 102 does not approve the received TWT Request, it may be configured to indicate a value different from the TWT Request in the TWT Response.

[0042] Based on the TWT Response transmitted by the AP MLD 102 in S403, the TWT information is set in the AP MLD 102 and the STA MLD 103 and a link is established.

[0043] After setting the TWT information in the AP MLD 102 and the STA MLD 103, the AP MLD 102 periodically transmits a Beacon frame including the set TWT information (S404). This allows the AP MLD 105 to receive and acquire the TWT information in the AP MLD 102 and the STA MLD 103.

[0044] Although FIG. 4 illustrates an example of a flow for setting TWT information at the time of initial link setup between the AP MLD 102 and the STA MLD 103, the flow may be started based on the STA MLD 103 transmitting a TWT Request after link setup.

[0045] Furthermore, in this embodiment, the flow of setting TWT information in the AP MLD 102 and the STA MLD 103 has been described, but the AP MLD 105 and the STA MLD 106 may be configured to set TWT information and establish a link using a similar flow.

[0046] (Elements Used for Sharing TWT Information) First, before describing the flow of the TWT information sharing process, elements included in a radio frame used when sharing TWT information used in the TWT information sharing process will be described.

[0047] 5 shows an example of a frame format of a Reduced Neighbor Report Element in this embodiment. In this embodiment, the Reduced Neighbor Report Element is used to share TWT information of other networks with the network that the device establishes or connects to. Note that in the following description, when describing each field included in the Reduced Neighbor Report Element, only the name of each field is used, and the field itself is omitted.

[0048] 5 includes an Element ID 501, a Length 502, and Neighbor AP Information Fields 503. The Element ID 501 is an identifier for identifying the Information Element, and in this embodiment, includes an identifier indicating the Reduced Neighbor Report Element. The Length 502 is a field indicating the data length of the Element, and in this embodiment, includes information indicating the data length of the Neighbor AP Information Fields 503. The Neighbor AP Information Fields 503 are fields that indicate information about different networks, and in this embodiment, contain TWT information about different networks. The information contained in the Neighbor AP Information Fields 503 will be described later.

[0049] Each communication device generates the Reduced Neighbor Report Element shown in FIG. 5 in order, starting with Element ID 501, and transmits it to other communication devices. In this case, each communication device generates all fields in the element before transmitting. Specifically, each communication device generates all of Element ID 501, Length 502, and Neighbor AP Information Fields 503 before transmitting them to other communication devices. Alternatively, each AP MLD may transmit in parallel with generating the fields. Specifically, each communication device may transmit, for example, the generated Element ID 501 and the Length 502 in parallel.

[0050] Each communication device transmits a MAC (Medium Access Control) frame, such as a Beacon frame or a Probe Response frame, including the Reduced Neighbor Report Element shown in Fig. 5. In addition to these MAC frames, each communication device can also add this Element to MAC frames such as an Association Response frame or a Reassociation Response frame.

[0051] The Neighbor AP Information Fields 503 include one or more Neighbor AP Information fields. Each Neighbor AP Information field includes a TBTT Information Header 504, an Operating Class 505, a Channel Number 506, and a TBTT Information Set 507. Each AP indicated by each Neighbor AP Information field may be referred to as a reported AP. TBTT stands for Target Beacon Transmission Time. The TBTT Information Header 504 includes information indicating the data length of the TBTT Information Set 507 and information indicating the number of TBTT Information fields included in the TBTT Information Set 507. The number of TBTT Information fields is indicated by the number of fields actually included in the TBTT Information Set 507 minus 1. The Operating Class 505 indicates the start frequency of the channel. Furthermore, the primary channel of the reported AP is indicated based on the information indicated by the Operating Class 505 and the Channel Number 506.

[0052] The TBTT Information Set 507 includes one or more TBTT Information. The information included in each TBTT Information included in the TBTT Information Set 507 will be described later. Note that the Neighbor AP Information Fields 503 can include information about multiple other APs by including multiple Neighbor AP Information. Furthermore, a communication device that receives a Reduced Neighbor Report Element can efficiently control communication by identifying the primary channel using the Operating Class 505 and the Channel Number 506.

[0053] The TBTT Information Set 507 includes one or more TBTT Information items, each of which includes a Neighbor AP TBTT Offset 508, a BSSID 509, a Short SSID 410, BSS Parameters 511, a 20 MHz PSD 511, MLD Parameters 513, and TWT information 514. The Neighbor AP TBTT Offset 508 indicates an offset in Time Units (TUs) from the TBTT immediately before the reported AP to the next TBTT. BSSID 509 indicates the Basic Service Set Identifier (BSSID) of the reported AP. Short SSID 510 is a 32-bit value calculated from the Service Set Identifier (SSID) of the network established by the reported AP. BSS Parameters 511 indicates various information related to the reported AP indicated by BSSID 509. 20 MHz PSD 511 is information indicating the maximum transmission power, for example, the maximum transmission power corresponding to the 20 MHz primary channel of the reported AP. MLD Parameters 513 is information about the AP MLD to which the reported AP belongs, and includes, for example, an AP MLD ID that is an identifier of the AP MLD and a Link ID that is an identifier of the link of the reported AP within the AP MLD. TWT information 514 is a field that includes TWT information of the reported AP, and the element includes TWT information of other networks for sharing.

[0054] The TWT information 514 includes a Control 515 and a TWT Parameter information 516. The Control 515 is information related to the information included in the TWT Parameter information 516, and includes, for example, information indicating whether the TWT information is a broadcast TWT, an individual TWT, or TWT information indicating a TBTT interval. Note that a broadcast TWT is a TWT in which TWT information is set between an AP and multiple STAs, and an individual TWT is a TWT in which TWT information is set on a one-to-one basis between an AP and a STA. The TWT Parameter information 516 includes a Request Type 517, a Target Wake Time 518, a Nominal Minimum TWT Wake Duration 519, a TWT Wake Interval Mantissa 520, a Broadcast TWT Info 521, and a Restricted TWT Traffic Info 522. The Request Type 517 includes, for example, a TWT flow identifier that identifies a TWT flow controlled based on the TWT information included in the TWT information. Target Wake Time 518 is information indicating the time until the next SP, and includes a positive integer corresponding to the Timing Synchronization Function (TSF) time requesting the STA to release the Doze state. Nominal Minimum TWT Wake Duration 519 is information indicating the expected time from the start to the end of the SP, and includes information indicating the expected minimum time the STA needs to be in the Awake state in order for the STA to complete the exchange of radio frames after releasing the Doze state. TWT Wake Interval Mantissa 520 is information indicating the interval between the start timing of each SP, and includes information indicating the value of the mantissa of the value indicating the interval at which the STA releases the Doze state. The information included in Broadcast TWT Info 521 will be described later.The Restricted TWT Traffic Info 522 specifies, in a bitmap format, a Traffic Identifier (TID) for a specific radio frame in the downlink (DL) and uplink (UL) communication directions.

[0055] Broadcast TWT Info 521 includes Restricted TWT Traffic Info Present 523, Restricted TWT Schedule Info 524, Broadcast TWT ID 525, and Broadcast TWT Persistence 526. Restricted TWT Traffic Info Present 523 includes information indicating whether Restricted TWT Traffic Info 522 is included. Restricted TWT Schedule Info 524 will be described later. Broadcast TWT ID 525 stores information for identifying TWT information of a broadcast TWT set by a reported AP. Broadcast TWT Persistence 526 stores information indicating the number of TBTTs in the SP indicated by the TWT information.

[0056] The Restricted TWT Schedule Info 524 will be explained using FIG. 6. FIG. 6 is a diagram for explaining the values ​​included in the Restricted TWT Schedule Info 524 and the meanings indicated by these values. Values ​​0 to 3 are used when the AP notifies the STAs in its own BSS of the TWT schedule. 0 indicates that the TWT is idle, while 1 and 3 indicate that the TWT schedule is active. 2 indicates that the schedule is active but that new participation is unlikely. The following values, 4 and 5, mean that the TWT information indicates the TWT schedule of another network (OBSS).

[0057] If the Restricted TWT schedule Info 524 contains 4, it indicates that the TWT information is TWT information of another network and the TWT schedule based on the TWT information is active in another BSS, and if the field 524 contains 5, it indicates that the TWT information is TWT information of another network and the TWT schedule based on the TWT information is idle in another BSS.

[0058] (TWT Information Sharing Process) Next, an example of a flowchart of a process in which the AP MLD 105 shares the TWT information of the network 101 with the STA MLD 106 using the above-mentioned Reduced Neighbor Report Element will be described with reference to FIG. In this embodiment, the AP MLD 105 acquires the TWT information of the network 101 from a wireless frame (including the TWT information of the network 101) transmitted by the AP MLD 102. The AP MLD 105 then shares the acquired TWT information of the network 101 with the STA MLD 106 of the network 104. This flowchart shows processing that is executed by the control unit 202 reading and executing a computer program stored in the storage unit 201. For example, this flowchart starts immediately after the AP MLD 105 transmits a Beacon frame that it periodically transmits. This flowchart also shows processing that is executed by the AP MLD 105 receiving a Beacon frame, a Probe Response frame, an Association Response frame, and so on from the AP MLD 102 constituting a different network. The process may be started in response to reception of a wireless frame such as a Response frame, etc. Note that this flowchart shows an excerpt of the process related to sharing the TWT information of the OBSS with the STAs of the BSS.

[0059] First, in S701, the AP MLD 105 receives a wireless frame transmitted by the AP MLD 102 (for example, a beacon frame transmitted by the AP MLD 102 in S404) via the frame transceiver 303. If the wireless frame contains TWT information, the process proceeds to S702; if the wireless frame does not contain TWT information, the process ends. The wireless frame received in S701 is a MAC frame transmitted by the AP MLD 102, and is assumed to be, for example, a beacon frame, a probe response frame, an association response frame, or other management frame, but is not limited to these. For example, the wireless frame may also be a control frame, an action frame, or the like.

[0060] Next, in S702, the TWT information acquisition unit 301 of the AP MLD 105 acquires the TWT information of the network 101 from the wireless frame including the TWT information received in S701.

[0061] In S703, the AP MLD 105 determines whether a predetermined period has elapsed since the start of this flow. In this embodiment, the predetermined period is the transmission interval of the Beacon frame transmitted by the AP MLD 105. In other words, in this embodiment, the AP MLD 105 determines whether a predetermined period (e.g., 100 TU) has elapsed since the transmission of the previous Beacon frame. If it is determined in S703 that the predetermined period has elapsed (Yes in S703), the process proceeds to S704. If it is determined in S703 that the predetermined period has not elapsed (No in S703), the process proceeds to S701.

[0062] Next, in S704, it is determined whether TWT information of a different BSS has been acquired within a predetermined period. If it is determined in S704 that TWT information of a different BSS has been acquired within the predetermined period (Yes in S704), the process proceeds to S705. If it is determined that TWT information of a different BSS has not been acquired within the predetermined period (Yes in S704), the process proceeds to S701.

[0063] Then, in S705, the AP MLD 105 stores the TWT information of the network 101 acquired in S702 in the above-mentioned Reduced Neighbor Report Element, and transmits a wireless frame including this element to the STA MLD 106 via the frame transceiver 303. In this element, the Restricted TWT schedule Info subfield is set to 4. Note that the wireless frame transmitted by the AP MLD 105 in S705 is a MAC frame, and is assumed to be, for example, a management frame such as a Beacon frame, a Probe Response frame, or an Association Response frame, but is not limited to this. For example, a control frame or an action frame may also be used. Note that in this embodiment, an example has been described in which the TWT information of a different network includes only the TWT information of the network 101, but this is not limiting. For example, it is assumed that multiple networks other than the network 104 exist around the AP MLD 105, and the AP MLD 105 may receive TWT information for multiple different BSSs before a predetermined period of time has elapsed. The TWT information sharing process in this case will be briefly described using the flow chart described above. First, the AP MLD 105 receives a wireless frame containing TWT information for a first different BSS in S701. The AP MLD 105 then acquires the TWT information for the first BSS from the received wireless frame. Then, before the predetermined period of time has elapsed, the AP MLD 105 receives a wireless frame containing TWT information for a second different BSS (No in S703 and S701). The AP MLD 105 then acquires the TWT information for the second BSS from the received wireless frame. Then, after a predetermined period of time has elapsed (Yes in S703), the acquired TWT information of the first BSS and the TWT information of the second BSS are stored in a Reduced Neighbor Report Element, and a wireless frame including the element is transmitted to the STA MLD 106 via the frame transceiver 303 (S705). In this way, when TWT information of multiple networks is received within the predetermined period of time, the TWT information of the multiple networks is shared at once in S507. After transmitting the wireless frame including the TWT information in S705, the AP MLD 105 advances the process to S706.In S706, the AP MLD 105 determines whether to stop the network. If it is determined that the network should be stopped, the network provision process is terminated and the series of processes is also terminated. On the other hand, if it is determined that the network should not be stopped, the process proceeds to S701 and a series of notification controls are performed. Specifically, the AP MLD 105 may determine that the network should be stopped when it receives a shutdown operation or a power-off operation (not shown).

[0064] In this way, the AP MLD 105 stores the TWT information of the network 101 received from the AP MLD 103 in the above-mentioned Reduced Neighbor Report Element and transmits it to the STA MLD 106, thereby enabling information about the TWT of different networks to be shared with the network to which the own device belongs. Note that the AP MLD 105 may be configured to transmit, as the above-mentioned TWT information, at least information about Target Wake Time 518, Nominal Minimum TWT Wake Duration 519, and TWT Wake Interval Mantissa 520 in S703. Each piece of information is information about the start timing of SPs in other networks, information about the time of the SPs, and information about the interval between the start timings of each SP, respectively. Therefore, the STA MLD 106 can recognize the start timing of the next SP of another network by recognizing the information included in Target Wake Time 518. Furthermore, the STA MLD 106 can recognize the time of the SP of another network by recognizing the information included in Nominal Minimum TWT Wake Duration 519. Furthermore, the STA MLD 106 can recognize the interval of the start timing of the SP of another network by recognizing the information included in TWT Wake Interval Mantissa 520.

[0065] A STA connected to the AP MLD 105, represented by the STA MLD 106, etc., performs transmission suppression control so as not to perform its own data transmission process during the SP of the recognized other network.

[0066] As described above, this allows the STA MLD 106 to grasp the start timing and time of the SP of the network 101, and to suppress transmission in the SP of the other network that has been grasped, thereby preventing interference with communications in the SP of the other network.

[0067] 7, the beacon frame transmission interval is used as an example of a period for collecting OBSS TWTs, and the OBSS TWT information received during that period is notified to the STAs of the BSS. However, this is not limiting. For example, the AP MLD 105 can be configured to manage the TWT information transmitted by the OBSS AP in association with its last acquisition time, and notify the STAs of the BSS of the OBSS TWT information acquired within a predetermined reference time (e.g., within one minute).

[0068] Second Embodiment In the first embodiment, the AP MLD 105 shared the TWT information of the network 101 with the STA MLD 106 using the Reduced Neighbor Report Element. In the second embodiment, an example will be described in which a Neighbor Report Element is used instead of the Reduced Neighbor Report Element. Note that the hardware configuration and functional configuration of each communication device in this embodiment are the same as those in the first embodiment, and therefore a description thereof will be omitted. Furthermore, the setting of the TWT information between the AP MLD 102 and the STA MLD 103 in the network 101 described with reference to FIG. 4 and the process in which the AP MLD 105 shares the TWT information of the network 101 with the STA MLD 106 described with reference to FIG. 7 are also the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0069] The Neighbor Report Element in this embodiment will be described with reference to Fig. 8. The AP MLD 105 stores the TWT information of the different BSSs acquired in S702 in the element, and transmits a wireless frame including the element to the STA MLD 106 via the frame transceiver 303. The wireless frame including the element is a MAC frame, and may be, for example, a management frame such as a Beacon frame, a Probe Response frame, or an Association Response frame, but is not limited to these. For example, a control frame or an action frame may also be used.

[0070] 8 includes an Element ID 801, Length 80, BSSID 803, BSSID Information 804, Operating Class 805, Channel Number 806, PHY Type 807, and Optional Subelement 808. The Element ID 801, Length 80, BSSID 803, BSSID Information 804, Operating Class 805, and Channel Number 806 contain the same information as the fields with the same names described above, and therefore, description thereof will be omitted. PHY Type 807 indicates the PHY type of the AP indicated by BSSID 803 .

[0071] The Optional Subelement 808 includes a Subelement ID 809 , a Length 810 , a Control 515 , and TWT Parameter Information 516 .

[0072] In this way, the AP MLD 105 can share the TWT information of the network 101 with the STA MLD 106 by using the above-mentioned Neighbor Report Element.

[0073] Third Embodiment In a third embodiment, the AP MLD 105 shares the TWT information of the network 101 with the STA MLD 106 by using a TWT Element instead of each of the above-described Elements.

[0074] Note that the hardware configuration and functional configuration of each communication device in this embodiment are the same as those in the first embodiment, and therefore their explanations will be omitted. Furthermore, the setting of TWT information between the AP MLD 102 and the STA MLD 103 in the network 101, which was explained using Fig. 4, and the process in which the AP MLD 105 shares the TWT information of the network 101 with the STA MLD 106, which was explained using Fig. 7, are also the same as those in the first embodiment, and therefore their explanations will be omitted.

[0075] The TWT Element in this embodiment will be described with reference to Figure 9. The AP MLD 105 stores the TWT information of the different BSSs acquired in S702 above in the element, and transmits a wireless frame including the element to the STA MLD 106 via the frame transceiver 303. The wireless frame including the element is a MAC frame, and is assumed to be, for example, a management frame such as a Beacon frame, a Probe Response frame, or an Association Response frame, but is not limited to these. For example, a control frame or an action frame may also be used.

[0076] The TWT Element shown in FIG. 9 includes an Element ID 801, a Length 80, a Control 515, and TWT Parameter Information 903.

[0077] In this embodiment, the TWT Parameter Information 903 included in the TWT Element further includes a BSSID 904 in addition to the above-described fields. The BSSID 904 stores information indicating the BSSID of the AP to which the TWT information indicated by the TWT Parameter Information 903 is set. Note that in this embodiment, the BSSID 904 is stored immediately after the Restricted TWT Traffic Info 522, but is not limited thereto. For example, the BSSID 904 may be configured to be stored immediately after the Broadcast TWT Persistence 526, and it is sufficient that the BSSID 904 is stored at least in the TWT Parameter Information 903 included in the TWT Element. This allows the STA to identify which network the TWT information indicated by the TWT Element is related to, and even if there are multiple other networks, it becomes possible to identify which network the TWT information belongs to.

[0078] In this way, the AP MLD 105 can share the TWT information of the network 101 with the STA MLD 106 by using the above-mentioned TWT Element.

[0079] In the above-described embodiments, the flow in which the AP MLD shares the TWT information of another network with the STA MLD has been described, but the present invention is not limited to this. For example, when the STA MLD receives and acquires the TWT information of another network, the STA MLD may be configured to share the TWT information of the other network using any of the above-described Elements.

[0080] Furthermore, in each of the above-described embodiments, the TWT information of other networks is shared, but this is not limiting, and each element may be configured to share only information about the R-TWT.

[0081] Furthermore, at least a part or all of the flowcharts of the AP MLD 105 shown in Figures 4 and 7 may be realized by hardware. When realizing 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 implemented as hardware. Alternatively, it may be implemented by an ASIC (Application Specific Integrated Circuit).

[0082] The present invention can also be realized by supplying a program that realizes one or more of the 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.The present invention can also be realized by a circuit (e.g., an ASIC) that realizes one or more of the functions.

[0083] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention.

[0084] This application claims priority based on Japanese Patent Application No. 2023-185970, filed on October 30, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A communication device comprising: a receiving means for receiving a wireless frame including information regarding a Target Wake Time (TWT) of a first network established by a first communication device different from the communication device; and a transmitting means for transmitting a predetermined frame including a predetermined element including information for identifying the first communication device and information regarding the TWT of the first network.

2. The communication device according to claim 1, further comprising: an acquisition means for acquiring information regarding the TWT of the first network based on the wireless frame received by the receiving means; and a generation means for generating the specified frame to be transmitted by the transmitting means based at least on the information regarding the TWT of the first network acquired by the acquisition means.

3. A communication device as described in claim 1 or claim 2, characterized in that, when the communication device is not participating in the first network, the transmitting means transmits the specified frame including the specified element containing information for identifying the first communication device and information regarding the TWT.

4. The communication device according to any one of claims 1 to 3, further comprising construction means for constructing a second network.

5. A communication device according to any one of claims 1 to 4, further comprising an establishment means for establishing a link with a second communication device different from said communication device, said establishment means being capable of establishing a plurality of links with said second communication device, each via a different frequency channel.

6. A communication device according to any one of claims 1 to 5, characterized in that the predetermined frame is a management frame.

7. The communication device according to any one of claims 1 to 6, wherein the communication device is an Access Point Multi-Link Device conforming to the IEEE 802.11 series standard.

8. The communication device according to any one of claims 1 to 7, wherein the predetermined element is a Reduced Neighbor Report Element, and the information for identifying the first communication device and the information regarding the TWT of the first network are included in the Reduced Neighbor Report Element.

9. The communication device according to any one of claims 1 to 7, wherein the predetermined element is a Neighbor Report Element, and the information for identifying the first communication device and the information regarding the TWT of the first network are included in the Neighbor Report Element.

10. A communication device according to any one of claims 1 to 7, characterized in that the specified element is a TWT Element, and information identifying the first communication device and information relating to the TWT of the first network are included in the TWT Element.

11. A method for controlling a communication device, comprising: a receiving step of receiving a wireless frame including information regarding a Target Wake Time (TWT) of a first network established by a first communication device different from the communication device; and a transmitting step of transmitting a predetermined frame including a predetermined element including information for identifying the first communication device and information regarding the TWT of the first network.

12. A program for causing a computer to function as the control method for a communication device according to claim 11.

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