Communication device, control method for same, and program

Abstract

This communication device transmits a trigger frame for requesting notification of a period of unavailability of communication in another communication device, the period of unavailability being used to restrict communication with the other communication device. The communication device receives a response frame to the trigger frame from the other communication device. The response frame includes a first field in which a value corresponding to the start time of the period of unavailability is stored, and a second field in which a value corresponding to the length of the period of unavailability is stored, and if the length is undefined or exceeds a maximum length, which is an upper limit to which the second field can be set, the value of the second field is set to a specific value.

Description

Communication device, its control method, and program

[0001] The present disclosure relates to communication control technology in a wireless LAN.

[0002] Currently, wireless LANs (Local Area Networks) represented by the IEEE (Institute of Electrical and Electronics Engineers) 802.11 series of standards are widely used. The IEEE 802.11 series of standards includes standards such as IEEE 802.11a / b / g / n / ac / ax / be standards. Also, in order to further improve the reliability of communication, the development of the IEEE 802.11bn standard is underway as a successor standard to the IEEE 802.11be standard.

[0003] In the IEEE 802.11bn standard, the introduction of an operation mode called Dynamic Unavailability Operation (DUO) mode is being considered (see Non-Patent Document 1). The DUO mode is a mode in which a station (STA) notifies an access point (AP) of a period during which communication with the AP cannot be performed (a period during which communication is unavailable), and restricts communication between the STA and the AP during that period.

[0004] Laurent Cariou et al., "PDT MAC Coexistence (IEEE 802.11-24 / 2040r9)", 2024

[0005] In the DUO mode, the AP requests the STA to notify it of the period during which communication in the STA is unavailable, and the STA, as a response, transmits a response frame including information indicating the start time and length of the unavailable period to the AP. However, for example, if the start time of the unavailable period is determined in the STA but the length of the unavailable period is undetermined or exceeds the upper limit that can be set for the response frame, the STA cannot appropriately notify the AP of the unavailable period. As a result, when there is a period during which communication in the STA is unavailable, the AP may not be able to appropriately communicate with the STA.

[0006] This disclosure provides a technology that enables communication devices (APs) to appropriately notify other communication devices (STAs) of periods during which communications are unavailable.

[0007] A communication device according to one aspect of the present disclosure is a communication device compliant with the IEEE 802.11 standard, comprising: transmitting means for transmitting a trigger frame to another communication device for requesting notification of a period of unavailability of communication on the other communication device, which is used to restrict communication with the other communication device; and receiving means for receiving a response frame from the other communication device, which includes a first field storing a value corresponding to the start time of the unavailability period and a second field storing a value corresponding to the length of the unavailability period, wherein the value of the second field is set to a specific value when the length is undetermined or exceeds a maximum length which is an upper limit that can be set for the second field.

[0008] A communication device according to another aspect of the present disclosure is a communication device compliant with the IEEE 802.11 standard, comprising: receiving means for receiving a trigger frame from another communication device for requesting notification of a period of unavailability of communication in the communication device, which is used to restrict communication with the communication device; and transmitting means for transmitting a response frame to the other communication device, which includes a first field storing a value corresponding to the start time of the unavailability period and a second field storing a value corresponding to the length of the unavailability period, wherein if the length is undetermined or exceeds a maximum length which is an upper limit that can be set for the second field, the value of the second field is set to a specific value.

[0009] According to this disclosure, it will be possible to appropriately notify a communication access point (AP) of information regarding periods when communication on other communication devices (STAs) is unavailable.

[0010] Other features and advantages of the technical ideas derived from this disclosure will become apparent from the following description with reference to the attached drawings. In the attached drawings, the same or similar components are given the same reference numeral.

[0011] The attached drawings are included in the specification and constitute part thereof, illustrating embodiments in this disclosure and are used together with the description to explain the technical ideas derived from this disclosure.

[0012] Figure 1 is a diagram showing an example of the configuration of a wireless communication system. Figure 2 is a block diagram showing an example of the hardware configuration of a communication device. Figure 3 is a block diagram showing an example of the functional configuration of a communication device. Figure 4 is a diagram showing an example of the communication processing flow of AP and STA (comparative example). Figure 5 is a diagram showing an example of the configuration of a response frame. Figure 6 is a diagram showing an example of the setting values ​​of fields in a response frame. Figure 7 is a diagram showing an example of the setting patterns of fields in a response frame. Figure 8 is a flowchart showing an example of the procedure of processing performed by AP. Figure 9 is a flowchart showing an example of the procedure of case determination processing (S103). Figure 10 is a diagram showing an example of the communication processing flow of AP and STA (Case 1). Figure 11 is a diagram showing an example of the communication processing flow of AP and STA (Case 2). Figure 12A is a diagram showing an example of the communication processing flow of AP and STA (Cases 3 and 4). Figure 12B is a diagram showing an example of the communication processing flow of AP and STA (Cases 3 and 4). Figure 13A is a flowchart showing an example of the procedure of processing performed by AP. Figure 13B is a flowchart showing an example of the procedure of processing performed by STA. Figure 14A is a flowchart showing an example of the processing steps performed by the AP. Figure 14B is a flowchart showing an example of the processing steps performed by the STA. Figure 15 is a diagram showing an example of the communication processing flow of the AP and STA (Case 5). Figure 16 is a diagram showing an example of the communication processing flow of the AP and STA (Case 6).

[0013] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claims. While the embodiments describe multiple features, not all of these features are necessary, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0014] <System Configuration> Figure 1 shows an example configuration of a wireless communication system according to the embodiment of this disclosure. The wireless communication system is composed of communication devices that perform wireless LAN (Local Area Network) communication compliant with the IEEE 802.11 series standard (IEEE 802.11 standard). In Figure 1, the communication devices show a state in which an access point (AP) and a station (STA) exist, with one AP (AP101) and three STAs (STA102a, STA102b, and STA102c). However, this is just an example, and for example, the number of STAs may be one or two, or the number of APs and STAs may be more.

[0015] In the example shown in Figure 1, STA102a, STA102b, and STA102c are wirelessly connected to the Basic Service Set (BSS), a wireless network formed by AP101. AP101 is configured to communicate with each STA connected to the BSS. In the following, when STA102 is mentioned, it refers to STA102a, STA102b, and STA102c, respectively.

[0016] The communication devices (AP101 and STA102) may be, but are not limited to, a wireless LAN router, a personal computer (PC), a camera, a tablet terminal, a smartphone, a mobile phone, a video camera, a headset, or a printer. Alternatively, the communication devices (AP101 and STA102) may be information processing devices equipped with a wireless chip capable of performing wireless communication compliant with the IEEE 802.11 series standard.

[0017] In this embodiment, STA 102 is configured to operate in Dynamic Unavailability Operation (DUO) mode as defined in the IEEE 802.11 series standard. DUO mode is a mode in which STA notifies AP of a period during which it cannot communicate with AP (communication unavailability period) and restricts communication between STA and AP during that period. The unavailability period is expressed by the start time (start timing) and the length of time the period is unavailable. Note that the DUO mode in this embodiment is an example of a mode that restricts communication during a period set as a period during which the communication device (STA) cannot communicate.

[0018] A STA operating in DUO mode will not communicate with an AP during periods of unavailability. This allows for, for example, a reduction in the STA's power consumption, or enables other operations within the STA, such as communication using a different standard that may interfere with communication with the AP. The coexistence of communication using another standard (e.g., Bluetooth®) that may interfere with communication using standards such as IEEE 802.11bn within the AP or STA may be called In-Device Coexistence (IDC). Furthermore, when the AP is notified of an unavailability period by the STA, it restricts (stops) communication to the STA so as not to send frames (data) during that period. This prevents the loss of frames due to the AP sending frames during the STA's communication unavailability period. In other words, DUO mode can be said to be a mode used for the coexistence of the STA with other wireless technologies. Furthermore, if other communications that may interfere with communication with the AP are taking place within the STA during the period of unavailability, the AP can communicate with the STA while avoiding such interference with other communications.

[0019] Figure 4 is a sequence diagram showing an example of the communication flow between the AP and the STA, and illustrates a comparative example to this embodiment. In DUO mode, the AP requests the STA to notify it of the period during which communication is unavailable via a trigger frame, and the STA sends a response frame to the AP in response, which includes information indicating the start time and length of the unavailable period. In this comparative example, it is assumed that the length of the unavailable period exceeds the upper limit that can be set for the response frame sent from the STA to the AP. The upper limit that can be set for the response frame corresponds to the upper limit that can be set for the Unavailability Duration field, which is included in the response frame and will be described later (the maximum length which corresponds to the maximum value stored in the field). In this case, the STA cannot set the value of the Unavailability Duration field in the response frame to a value that indicates the length of the actual unavailable period (in this example, the period during which communication takes place between the STA and other network devices). Therefore, the STA sets the value of the field to the maximum value within the range of configurable values.

[0020] In the example shown in Figure 4, the AP sends a trigger frame 401 to the STA, and the STA sends a response frame 402 to the AP in response to the trigger frame 401. The trigger frame 401 consists of a Buffer Status Report Poll (BSRP) trigger frame, and the response frame 402 consists of a Multi-STA Block Ack (M-BA) frame. As will be described later, the AP obtains information on the start time and length (duration) of the unavailability period, which are specified in the Unavailability Target Start Time field and the Unavailability Duration field, respectively, contained in the response frame 402. Based on the obtained information, the AP performs communication control to restrict (stop) communication with the STA during the unavailability period in order to avoid the interference described above.

[0021] The AP stops transmitting data (PPDU 403) to the STA by the start time indicated by the setting of the Unavailability Target Start Time field in the response frame received from the STA. Subsequently, the AP stops communicating with the STA for a period of time from that start time to the length indicated by the setting of the Unavailability Duration field. Once this period has ended, the AP resumes transmitting data (PPDU 404) to the STA.

[0022] On the other hand, the STA may communicate with other network devices during the unavailability period that restricts communication with the AP. However, this unavailability period may be longer than the unavailability period notified from the STA to the AP by the response frame 402 (the maximum length that can be set for the response frame 402). In this case, while communication between the STA and other network devices continues, the AP will resume sending data (PPDU 404) to the STA, causing interference between these communications. Thus, if other communications that may interfere with communication with the AP (e.g., BLE communication) are taking place within the STA during the unavailability period, the AP may be unable to communicate with the STA while avoiding such interference.

[0023] Therefore, in this embodiment, a technology is provided that enables communication devices (APs) to appropriately notify other communication devices (STAs) of periods when their communications are unavailable. This enables the APs to appropriately grasp the timing at which interference may occur as described above, thereby avoiding a decrease in communication performance due to interference. Specifically, the communication device (AP 101) sends a trigger frame to request notification of a period when communication is unavailable on another communication device (STA 102), which is used to restrict communication with the other communication device. The communication device receives a response frame from the other communication device in response to the trigger frame. The response frame includes a first field that stores a value corresponding to the start time of the unavailable period, and a second field that stores a value corresponding to the length of the unavailable period. If the length is undetermined or exceeds the maximum length which is the upper limit that can be set for the second field, the value of the second field is set to a specific value. The configuration of the communication device and the processing flow for performing such processing will be described below.

[0024] <Device Configuration> Figure 2 shows an example of the hardware configuration of the communication device (AP101 and STA102) in this embodiment. As an example of its hardware configuration, the communication device has, for example, 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. Note that these are just examples, and the communication device may have further configurations not shown in Figure 2, or some or all of the configurations shown in Figure 2 may be replaced by other configurations having similar functions.

[0025] The storage unit 201 is composed of one or more memories, such as ROM (Read Only Memory) and / or RAM (Random Access Memory). The storage unit 201 stores computer programs (instruction sets) for performing the various operations described later, and various information such as communication parameters for wireless communication. Note that one or more memories constituting the storage unit 201 may be other types of storage media, such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, DVDs, etc. The storage unit 201 may also be equipped with multiple memories.

[0026] The control unit 202 is composed of one or more processors, such as a CPU (Central Processing Unit) and / or an MPU (Micro Processing Unit). The control unit 202 controls the entire communication device by reading and executing computer programs (instruction sets) stored in the storage unit 201. The control unit 202 may also be configured to control the entire device in cooperation with the computer programs stored in the storage unit 201 and the OS (operating system). Furthermore, the control unit 202 may be equipped with multiple processors, such as a multi-core processor, and configured to control the entire device with these multiple processors.

[0027] The control unit 202 generates data or signals (wireless frames) to be transmitted in communication with other communication devices. The control unit 202 further controls the functional unit 203 to perform predetermined processes such as wireless communication, imaging, printing, and projection. The functional unit 203 consists of hardware for the communication device to perform predetermined processes. If the communication device is a printer, the functional unit 203 is a printing device and performs printing based on image data acquired via the communication unit 206, for example. If the communication device is a scanner, the functional unit 203 is a reading device and outputs the image data generated by scanning to the outside, for example via the communication unit 206. If the communication device is a camera, the functional unit 203 includes an image sensor and a lens and outputs the image data obtained by imaging with the camera to the outside, for example via the communication unit 206. The functional unit 203 may also include configurations for realizing AP functions and / or STA functions.

[0028] The input unit 204 includes, for example, a touch panel, hard keys, and buttons, and accepts various operations from the user. The output unit 205 includes, for example, a display, speaker, and vibrator, and provides various outputs to the user. Here, the output from the output unit 205 may be one or more of the following: screen display on the display, audio output from the speaker, and vibration output. The input unit 204 and the output unit 205 may be implemented as a single module, such as a touch panel display. The input unit 204 and the output unit 205 may also be built into the communication device or implemented by an external input / output device. In this case, the communication device has an input / output interface for connecting to the input / output device.

[0029] The communication unit 206 performs control for wireless communication compliant with the IEEE 802.11 series standard (IEEE 802.11 standard). The communication unit 206 can perform control for wireless communication compliant with, for example, the IEEE 802.11bn standard, or its successor standards or earlier legacy standards. The communication unit 206 can also perform control for wired communication such as wired LAN. The communication unit 206 controls the antenna 207 to send and receive signals for wireless communication generated by the control unit 202. For example, a communication device sends and receives various data such as image data, document data, and video data to and from a partner device (another communication device) via the communication unit 206.

[0030] Furthermore, if the communication device supports the NFC standard and the Bluetooth® standard in addition to the IEEE 802.11 series standard, the communication unit 206 may control wireless communication in accordance with these communication standards. Also, if the communication device is capable of performing wireless communication in accordance with multiple communication standards, it may have separate communication units and antennas that support different communication standards.

[0031] Antenna 207 is, for example, an antenna capable of detecting and radiating radio waves in the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. Antenna 207 may also be configured to enable communication in the same frequency band as the communication unit 206. In this case, antenna 207 may be, for example, a multiband antenna capable of communication in multiple frequency bands. Figure 2 shows an example in which the communication device has only one antenna, but for example, multiple antennas may be used depending on the number of available spatial streams. If the communication device has multiple antennas, it may have a communication unit 206 corresponding to each antenna. Antenna 207 may be provided separately from the communication unit 206, or it may be configured as a single module together with the communication unit 206.

[0032] Figure 3 shows an example of the functional (software) configuration of the communication device (AP101 and STA102) in this embodiment. The communication device has, for example, a wireless LAN control unit 301, a frame generation unit 302, a frame analysis unit 303, a UI control unit 304, a storage control unit 305, and a DUO control unit 306 as its functional units (functional blocks). Note that the functional configuration shown in Figure 3 is just one example, and other functions may be added or the shown functions may be modified. For example, one functional block shown in Figure 3 may be divided into multiple units, or multiple functional blocks may be combined into one. Also, some functions may be omitted, or functions not shown may be added. In one example, at least some of the functions shown in Figure 3 may be realized by the control unit 202 executing a program stored in the storage unit 201. Also, at least some of the functions shown in Figure 3 may be realized using dedicated hardware.

[0033] The wireless LAN control unit 301 controls wireless LAN communication. The wireless LAN control unit 301 controls the communication unit 206 and the antenna 207 in order to send and receive wireless signals with other communication devices capable of wireless LAN communication. For example, the wireless LAN control unit 301 works in cooperation with the frame generation unit 302 and the frame analysis unit 303 to perform wireless frame communication control in accordance with the IEEE 802.11 series standard.

[0034] The frame generation unit 302 generates wireless frames such as control frames, management frames, and data frames. Each wireless frame includes a MAC (Medium Access Control) frame. MAC frames are also called MPDU (MAC Protocol Data Unit) or A-MPDU (Aggregate MAC Protocol Data Unit). A wireless frame consists of a preamble field and a data field. The data field stores MAC frames such as management frames, control frames, and data frames. Wireless control can be performed using each MAC frame generated by the frame generation unit 302. The content of the wireless control may be constrained by settings stored in the storage unit 201 by the storage control unit 305. The frame generation unit 302 can also accept settings from the user via the UI control unit 304. The wireless frames generated by the frame generation unit 302 are supplied to the wireless LAN control unit 301 and can be transmitted externally using the communication unit 206 and antenna 207 under the control of the wireless LAN control unit 301. In other words, AP101 and STA102 can transmit and receive UHR (Ultra High Reliability) PPDUs, which are wireless frames compliant with the IEEE 802.11bn standard. PPDU stands for Physical Layer Protocol Data Unit.

[0035] The frame analysis unit 303 analyzes wireless frames received via the communication unit 206 and antenna 207 under the control of the wireless LAN control unit 301. When analyzing wireless frames, the frame analysis unit 303 can determine the analysis method based on settings stored in the storage unit 201 by the storage control unit 305.

[0036] The UI control unit 304 controls the input unit 204 to accept input to a user interface (UI), such as a touch panel or buttons, for receiving operations on a communication device by a user (not shown). The UI control unit 304 can also control the output unit 205, for example, to perform controls to present information to the user, such as displaying images or outputting audio. The UI control unit 304 can also control the input unit 204 and the output unit 205 to display a graphical UI (GUI) on a display and accept operations on that GUI.

[0037] The memory control unit 305 controls the memory unit 201 to perform various information storage-related controls, such as saving, searching, and extracting programs and data on which the communication device operates. The DUO control unit 306 performs controls related to the DUO mode that is enabled or disabled in STA 102.

[0038] <Configuration of Response Frame> When STA102 starts operating in DUO mode, it sends a request frame to AP101 to request the activation of DUO mode. When AP101 receives the request frame from STA102 to request the activation of DUO mode, it sends a response frame to STA102 for the request frame. Upon receiving the response frame, STA102 activates DUO mode. This allows STA102 to notify AP101 of periods during which communication with AP101 will be unavailable.

[0039] After AP101 sends a response frame to a request frame, it requests STA102 to notify it of a period during which communication will be unavailable via a trigger frame. In response to the received trigger frame, STA102 sends a response frame to AP101 that includes information indicating the start time and length of the unavailable period. In this embodiment, the trigger frame and its response frame described above are configured as MAC frames compliant with the IEEE 802.11 series standard. The trigger frame is configured as a Buffer Status Report Pol (BSRP) trigger frame, and the response frame is configured as a Multi-STA Block Ack (M-BA) frame.

[0040] Figure 5 shows an example of the configuration of a response frame transmitted from STA102 as a response to a trigger frame requesting notification of a period of communication unavailability in DUO mode. The response frame, which consists of an M-BA frame, includes a BA Information field 501, which includes a Per AID TID Info field 511. The Per AID TID Info field 511 includes an AID TID Info field 521, a Block Ack Starting Sequence Control field 522, and a Block Ack Bitmap field 523. In DUO mode, the Block Ack Bitmap field 523 is used to notify the period of communication unavailability.

[0041] The Block Ack Bitmap field 523 includes the Unavailability Target Start Time field (subfield) 531, the Unavailability Duration field (subfield) 532, and the Reserved area 533. The Block Ack Bitmap field 523 is provided in octet units. Therefore, the Reserved area 533 is allocated according to the number of bits in the Unavailability Target Start Time field 531 and the Unavailability Duration field 532. To notify of the period of unavailability in DUO mode, the number of bits in the Unavailability Target Start Time field 531 and the Unavailability Duration field 532 are each set to 9 bits.

[0042] The period from the timing (start time) specified in the Unavailability Target Start Time field 531 to the period length (length) indicated in the Unavailability Duration field 532 is designated as the unavailable period in DUO mode. Figure 6 shows an example of the relationship between the settings of the Unavailability Target Start Time field 531 and the Unavailability Duration field 532 and the start time and period length (length) indicated (specified) by each setting. In the Unavailability Target Start Time field 531, for example, a time based on the time reference specified in the Beacon frame is specified, and the start time is specified in units of 64 microseconds. Additionally, the Unavailability Duration field 532 specifies the time length (period length) in units of 64 microseconds.

[0043] Figure 7 shows an example of values set for the Unavailability Target Start Time field 531 and the Unavailability Duration field 532 in the response frame of this embodiment. In this embodiment, the Unavailability Target Start Time field (hereinafter also referred to as the "UTST field") 531 corresponds to the first field in which a value corresponding to the start time of the unavailable period is stored. Also, the Unavailability Duration field (hereinafter also referred to as the "UD field") 532 corresponds to the second field in which a value corresponding to the length of the unavailable period is stored.

[0044] As shown in Figure 7, the response frame of this embodiment is configured to be able to notify various information from the STA102 to the AP101 by setting specific values for the UTST field 531 and the UD field 532. In the example of Figure 7, the following are defined as the specific values set for the UTST field 531 and the UD field 532. In this embodiment, as an example, 0 (a value with all bits being 0) or the maximum value (a value with all bits being 1) among the values that can be set for each field is used as a specific value (special value), but values other than these may be used. ● When the set value of the UD field 532 is 0 ("000000000"), it indicates that the unavailable period is not set in the STA102. ● When the set value of the UD field 532 is the maximum value ("111111111") among the values that can be set for the field, it indicates that the length of the unavailable period is undetermined or exceeds the upper limit (maximum length) that can be set for the field. ● When the set value of the UTST field 531 is the maximum value ("111111111") among the values that can be set for the field, it indicates that the start time of the unavailable period is undetermined.

[0045] In this embodiment, the above-mentioned specific values ​​(special values) are set for the UTST field 531 and UD field 532 in the response frame, according to the content of the notification from STA 102 to AP 101 regarding the period during which communication at STA 102 is unavailable. As shown in Figure 7, there are six possible patterns for setting the values ​​for the UTST field 531 and UD field 532, from Case 1 to Case 6 below. ● Case 1 is the case in which no period is set (or is not planned) at STA 102. ● Case 2 is the case in which the normal setting of the period of unavailable is performed within the range of values ​​that can be set for each field (for the UTST field 531, the range is "000000000" to "111111110", and for the UD field 532, the range is "000000001" to "111111110"). ●Case 3 is a case where the start time of the unavailability period is determined, but the length of the unavailability period is undetermined. ●Case 4 is a case where the start time of the unavailability period is determined, but the length of the unavailability period exceeds the maximum length which is the upper limit that can be set for the UD field 532. ●Case 5 is a case where the start time of the unavailability period is undetermined, but the length of the unavailability period is determined (the unavailability period will occur). ●Case 6 is a case where both the start time and length of the unavailability period are undetermined, but the unavailability period will occur.

[0046] In addition, in cases 5 and 6, the following are possible examples where the start time of the unavailability period is undetermined. For example, when STA102 and another network device (e.g., audio equipment) are connected via BLE communication, STA102 will be idle if the other network device is not performing voice communication. STA102 and the other network device maintain their connection, and voice data exchange occurs through control from the application program. In such cases, the timing of the voice data exchange (the start time of the unavailability period) is not predetermined, so the start time of the unavailability period may be undetermined.

[0047] When STA102 receives a trigger frame from AP101, it sets an unavailable period according to the communication state with other network devices in STA102, and notifies AP101 in a response frame about the set unavailable period. At that time, according to the setting situation of the unavailable period, a response frame is generated by performing any one of the above-described cases 1 to 6 on the UTS field 531 and the UD field 532 of the response frame, and is transmitted to AP101.

[0048] AP101 will receive a response frame including the UTS field 531 and the UD field 532 in which any one of the above-described cases 1 to 6 is set, from STA102. The AP101 of this embodiment is configured to determine (discriminate) which case of the settings shown in FIG. 7 is performed on the UTS field 531 and the UD field 532 when receiving the response frame, and execute a process corresponding to the determination result.

[0049] <Processing procedure> FIG. 8 is a flowchart showing an example of the processing procedure executed by AP101. The processing according to this procedure can be executed by AP101, for example, when the operation in the DUO mode is started in STA102.

[0050] First, AP101 sends a trigger frame to STA102 (S101) and waits for the reception of the response frame. When AP101 receives the response frame for the trigger frame from STA102 (YES in S102), it analyzes the contents of the received response frame and performs a case determination process (S103). The case determination process is performed in the procedure shown in Figure 9, which will be described later, and determines which of the cases shown in Figure 7 has been set for the UTST field 531 and UD field 532 in the response frame. AP101 then performs further processing corresponding to the determined case according to the determination result in the case determination process (S104), and terminates the processing in this procedure. As a result, AP101 performs communication control that restricts (stops) communication with STA102 during the period when communication with STA102 is unavailable, based on the information contained in the response frame received from STA102.

[0051] (S103: Case determination process) Figure 9 is a flowchart showing an example of the procedure for the case determination process in S103. This procedure determines which of the cases shown in Figure 7 the settings of the UTST field 531 and UD field 532 in the response frame correspond to.

[0052] When AP101 starts case determination processing based on the received response frame, it first determines whether the value of UD field 532 is 0 or not. If it determines that the value of UD field 532 is 0 (YES in S201), it determines that Case 1 has been set (S205) and terminates this process.

[0053] Furthermore, if the value of the UTST field 531 is not the maximum value (all bits are 1) (NO in S202) and the value of the UD field 532 is not the maximum value (all bits are 1) (NO in S203), AP101 makes the following determination. That is, AP101 determines that the setting for case 2 has been made (S206) and terminates this process. If the value of the UTST field 531 is not the maximum value (all bits are 1) (NO in S202) and the value of the UD field 532 is the maximum value (all bits are 1) (YES in S203), AP101 makes the following determination. That is, AP101 determines that the setting for case 3 or 4 has been made (S207) and terminates this process.

[0054] Furthermore, if the value of the UTST field 531 is the maximum value (all bits are 1) (YES in S202) and the value of the UD field 532 is not the maximum value (all bits are 1) (NO in S204), AP101 makes the following determination. That is, AP101 determines that the setting for case 5 has been made (S208) and terminates this process. If the value of the UTST field 531 is the maximum value (all bits are 1) (YES in S202) and the value of the UD field 532 is the maximum value (all bits are 1) (YES in S204), AP101 makes the following determination. That is, AP101 determines that the setting for case 6 has been made (S209) and terminates this process.

[0055] <Processing corresponding to Case 1> Referring to Figure 10, the case in which AP101 executes the processing corresponding to Case 1 in S104 will be explained. AP101 sends a trigger frame 1001 to STA102 and receives a response frame 1002 for the trigger frame 1001 from STA102. AP101 executes the processing corresponding to Case 1 based on the received response frame 1002.

[0056] Case 1 is a case where no unavailable period is set (or is not planned) for STA102. Therefore, AP101 continues to communicate with STA102 without performing any communication control that would restrict (stop) communication with STA102, thereby transmitting data (PPDU1003) to STA102.

[0057] <Processing corresponding to Case 2> Referring to Figure 11, the case in which AP101 executes the processing corresponding to Case 2 in S104 will be explained. AP101 sends a trigger frame 1001 to STA102 and receives a response frame 1002 for the trigger frame 1001 from STA102. AP101 executes the processing corresponding to Case 2 based on the received response frame 1002.

[0058] Case 2 is a case in which the normal setting of the unavailability period is performed within the range of values ​​that can be set for the UTST field 531 and UD field 532 in the response frame 1002. For this reason, AP 101 performs communication control that restricts communication with STA 102 during the unavailability period 1100 notified by the response frame 1002 (UTST field 531 and UD field 532). When the unavailability period 1100 ends, AP 101 resumes communication with STA 102 and sends data (PPDU 1004) to STA 102.

[0059] <Processing corresponding to Cases 3 and 4 (First Example)> Referring to Figure 12A, the case in which AP101 executes processing corresponding to Cases 3 and 4 in S104 will be explained. AP101 sends a trigger frame 1001 to STA102 and receives a response frame 1002 for the trigger frame 1001 from STA102. Based on the received response frame 1002, AP101 executes processing corresponding to Cases 3 and 4.

[0060] Cases 3 and 4 are cases where the length of the unavailability period notified in the response frame 1002 is undetermined or exceeds the upper limit (maximum length) that can be set for the UD field 532. Since the start time of the unavailability period is determined, AP 101 starts communication control that restricts communication with STA 102 at the start time of the unavailability period 1200 notified in the UTST field 531 of the response frame 1002. After that, AP 101 continues the communication control that restricts communication with STA 102 (transmission of PPDU to STA 102) even after the period of the maximum length that can be set for the UD field 532 has elapsed from the start time.

[0061] Furthermore, AP101 retransmits the trigger frame 1201 to STA102 after a period of the maximum length that can be set for the UD field 532 has elapsed from the start time of the unavailable period 1200. AP101 continues communication control that restricts communication with STA102 until a response frame 1202 for the trigger frame 1201 is received from STA102. At this time, AP101 may repeatedly retransmit the trigger frame 1201 at predetermined time intervals until a response frame 1202 for the trigger frame 1201 is received from STA102.

[0062] Figure 13A shows an example of the procedure for processing by AP101 (S104), corresponding to the example in Figure 12A. AP101 continues communication with STA102 (sending and receiving data (PPDU)) until the start time of the unavailable period 1200 notified in the UTST field 531 of the response frame 1002 (S301). After that, AP101 waits with communication with STA102 stopped until the maximum length of the period that can be set for the UD field 532 has elapsed from the start time of the unavailable period 1200 (S302). After the elapsed period of the maximum length, AP101 resends the trigger frame 1201 to STA102 at predetermined intervals (YES in S303) (S304). The resending of the trigger frame 1201 (S304) is repeatedly performed until a response frame 1202 for the trigger frame 1201 is received from STA102. In STA102, when the retransmitted trigger frame 1201 is received after the end of the unavailable period 1200, a response frame 1202 is sent from STA102 to AP101 in response to the trigger frame 1201.

[0063] Upon receiving response frame 1202 from STA102 (YES in S305), AP101 cancels the unavailable period setting (S306) and performs communication control to resume communication with STA102 (sending and receiving data (PPDU)) (S307). With this, AP101 terminates the processing according to this procedure.

[0064] Figure 13B shows an example of the processing procedure by STA 102, corresponding to the example in Figure 12A. When the unavailability period 1200 ends (YES in S311), STA 102 waits for the retransmitted trigger frame 1201 by AP 101 to be received. When AP 101 receives the trigger frame 1201 from AP 101 (YES in S312), it generates a response frame 1202 for the received trigger frame 1201 and sends the generated response frame 1202 to STA 102 (S313). At this time, the value of the UTST field 531 may be set to 0 in the response frame 1202 so as not to set an unavailability period.

[0065] Subsequently, STA102 cancels the setting of the unavailable period 1200 (S314) and performs communication control to resume communication with AP101 (sending and receiving data (PPDU)) (S315). With this, STA102 terminates the processing according to this procedure.

[0066] This process allows communication with STA 102 to resume after the unavailability period 1200, during which STA 102 may communicate with other network devices, exceeds the upper limit (maximum length) that can be notified in the response frame. This avoids interference with other communications that may occur due to communication with STA 102 during the unavailability period.

[0067] <Processing corresponding to Cases 3 and 4 (Second Example)> Referring to Figure 12B, a different process (second example) from the process shown in Figure 12A will be described for the case where AP101 executes the processing corresponding to Cases 3 and 4 in S104. AP101 sends a trigger frame 1001 to STA102 and receives a response frame 1002 for the trigger frame 1001 from STA102. Based on the received response frame 1002, AP101 executes the processing corresponding to Cases 3 and 4.

[0068] Similar to the process described above, AP101 initiates communication control that restricts communication with STA102 (sending PPDUs to STA102) at the start time of the unavailability period 1210, as notified in the UTST field 531 of response frame 1002. However, AP101 retransmits the trigger frame 1211 before the start time of the unavailability period 1210 and continues such communication control until a response frame 1212 for the trigger frame 1211 is received from STA102. This response frame 1212 is sent by STA102 via Unsolited transmission as a response to the retransmitted trigger frame 1211 after the unavailability period 1210 has ended.

[0069] Figure 14A shows an example of the procedure for processing by AP101 (S104), corresponding to the example in Figure 12B. AP101 continues communication with STA102 (sending and receiving data (PPDU)) until the start time of the unavailability period 1210, which is notified in the UTST field 531 of the response frame 1002 (S401). Immediately before the start time of the unavailability period 1210, AP101 resends the trigger frame 1211 to STA102 (S402).

[0070] Subsequently, upon receiving a response frame 1212 to the trigger frame 1211 from STA 102 (YES in S403), AP 101 cancels the unavailable period setting (S404) and performs communication control to resume communication with STA 102 (S405). With this, AP 101 terminates the processing according to this procedure.

[0071] Figure 14B shows an example of the processing procedure by STA 102, corresponding to the example in Figure 12B. STA 102 receives a trigger frame 1211 from AP immediately before the start of the unavailability period 1210 (S411). Then, when the unavailability period 1210 ends (YES in S412), STA 102 sends a response frame 1212 to AP 101 for the trigger frame 1211 (S413). At this time, the value of the UTST field 531 of the response frame 1212 may be set to 0 to avoid setting an unavailability period.

[0072] Subsequently, STA102 cancels the unavailability period 1210 setting (S414) and performs communication control to resume communication with AP101 (sending and receiving data (PPDU)) (S415). With this, STA102 terminates the processing according to this procedure.

[0073] Through this process, similar to the first example described above, even if the period of unavailability 1210 during which STA 102 can communicate with other network devices continues beyond the upper limit (maximum length) that can be notified in the response frame 1002, communication with STA 102 (sending and receiving data) can be resumed after the end of the unavailability period. This avoids interference with other communications caused by communicating with STA 102 during the unavailability period.

[0074] <Processing corresponding to Case 5> Referring to Figure 15, the case in which AP101 executes the processing corresponding to Case 5 in S104 will be explained. AP101 sends a trigger frame 1001 to STA102 and receives a response frame 1002 for the trigger frame 1001 from STA102. AP101 executes the processing corresponding to Case 5 based on the received response frame 1002.

[0075] Case 5 is a case where the start time of the unavailability period 1500 is undetermined at the time of transmission of response frame 1002, but the length of the unavailability period 1500 is determined (the unavailability period will occur). After receiving response frame 1002, AP 101 repeatedly retransmits trigger frame 1501 up to the maximum time that can be set for the UTST field 531 of the response frame 1002. This allows AP 101 to check the status of STA 102. If STA 102 has determined the start time of the unavailability period 1500, it notifies AP 101 of the unavailability period 1500 by response frame 1503.

[0076] Subsequently, similar to the process corresponding to Case 2, AP101 performs communication control that restricts communication with STA102 (sending and receiving data (PPDU)) during the unavailability period 1500 notified by the response frame 1503 (UTST field 531 and UD field 532). When the unavailability period 1500 ends, communication with STA102 is resumed, and data (PPDU 1004) is sent to STA102.

[0077] This process makes it possible to appropriately notify AP101 of information regarding the period of unavailability in STA102, even when the start time of the unavailability period in STA102 is undetermined, when sending the response frame 1002 to the trigger frame 1001. This prevents AP101 from inadvertently resuming communication (data transmission) with STA102 during the unavailability period, which could cause interference with other communications.

[0078] <Processing corresponding to Case 6> Referring to Figure 16, the case in which AP101 executes the processing corresponding to Case 6 in S104 will be explained. AP101 sends a trigger frame 1001 to STA102 and receives a response frame 1002 for the trigger frame 1001 from STA102. AP101 executes the processing corresponding to Case 6 based on the received response frame 1002.

[0079] Case 6 is a case where the start time and length of the unavailability period 1600 are undetermined at the time of transmission of response frame 1002, but the unavailability period 1600 will occur. AP 101 repeatedly retransmits the trigger frame 1601 after receiving response frame 1002. Alternatively, AP 101 periodically retransmits the trigger frame 1601 after receiving response frame 1002. This allows AP 101 to check the status of STA 102. When STA 102 determines the start time and length of the unavailability period 1600, it notifies AP 101 of the unavailability period 1600 by response frame 1603.

[0080] This process makes it possible to appropriately notify AP101 of information regarding the period of unavailability of communication in STA102, even when the start time and length of the unavailability period in STA102 are undetermined, when a response frame 1002 is transmitted to a trigger frame 1001. This prevents AP101 from inadvertently resuming communication (data transmission) with STA102 during the unavailability period, which could cause interference with other communications. In the above embodiment, the solution was described using the example of AP avoiding interference with other communications (e.g., BLE communication) that may interfere with communication with AP taking place inside STA. However, the method described in the above embodiment is also applicable to avoiding noise generated by the functional unit 203 inside STA that may interfere with communication with AP. When the functional unit 203 inside STA generates the above-mentioned noise, STA102 sets the timing at which the noise is generated, i.e., the timing at which the functional unit 203 operates, to the above-mentioned unavailability period. Furthermore, the same effect can be achieved by including information regarding the unavailability period in the response frame described above and transmitting it to AP 101. The methods described in Cases 1 to 6 above can also be applied to avoid noise generated by the internal functional unit 203 of the STA that may interfere with communication with the AP. In addition, in the above embodiment, information indicated by specific values ​​(special values) set in the UTST field 531 and UD field 532 within the response frame may be included in the Reserved area 533 shown in Figure 5.

[0081] As described above, the communication device (AP101) of this embodiment sends a trigger frame to another communication device (STA102) to request notification of a period during which communication is unavailable at that other communication device and is used to restrict communication with that other communication device. The communication device receives a response frame to the trigger frame, and the response frame includes a first field (Unavailability Target Start Time field) which stores a value corresponding to the start time of the unavailable period, and a second field (Unavailability Duration field) which stores a value corresponding to the length of the unavailable period. If the length is undetermined or exceeds the maximum length which is the upper limit that can be set for the second field, the value of the second field is set to a specific value. This makes it possible to notify AP101 of the information when the length of the unavailable period at STA102 exceeds the upper limit that can be set for the response frame. As a result, if other communications that may interfere with communication with AP101 occur within STA102 during the period of unavailability, AP101 will be able to communicate with STA102 while avoiding such interference with other communications.

[0082] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more functions.

[0083] The technical ideas derived from this disclosure are not limited to the exemplary embodiments disclosed, but are intended to encompass various modifications of the exemplary embodiments, or substitutions with equivalent structures or functions. The scope of the following claims should be interpreted in the broadest way to encompass all such modifications and equivalent structures and functions.

[0084] This application claims priority based on Japanese Patent Application No. 2025-027348, filed on 21 February 2025, and all of its contents are incorporated herein by reference.

Claims

1. A communication device compliant with the IEEE 802.11 standard, comprising: transmitting means for transmitting a trigger frame to another communication device for requesting notification of a period of unavailability of communication on that other communication device, which is used to restrict communication with that other communication device; and receiving means for receiving a response frame from the other communication device, which includes a first field storing a value corresponding to the start time of the unavailability period and a second field storing a value corresponding to the length of the unavailability period, wherein the value of the second field is set to a specific value when the length is undetermined or exceeds a maximum length which is an upper limit that can be set for the second field.

2. The communication device according to claim 1, wherein the specific value is the maximum value among the values ​​that can be set in the second field.

3. The communication device according to claim 1 or 2, further comprising control means for performing communication control that restricts communication with other communication devices during the unavailable period based on information contained in the response frame, wherein the control means starts the communication control at the start time notified in the first field when the specific value is set in the second field of the response frame, and continues the communication control even after a period of the maximum length has elapsed from the start time.

4. The communication device according to claim 3, wherein, if the second field of the response frame has the specific value set, the control means retransmits the trigger frame after a period of the maximum length has elapsed from the start time notified in the first field, and continues the communication control until the response frame for the trigger frame is received from the other communication device.

5. The communication device according to claim 4, wherein the control means repeatedly retransmits the trigger frame at predetermined time intervals until the response frame for the trigger frame is received from the other communication device.

6. The communication device according to claim 4 or 5, wherein, in the other communication device, when the retransmitted trigger frame is received after the end of the unavailability period, the response frame is transmitted from the other communication device to the communication device for the trigger frame.

7. The communication device according to claim 3, wherein the control means, when the specific value is set in the second field of the response frame, retransmits the trigger frame before the start time notified in the first field of the response frame, and performs the communication control until the response frame for the trigger frame is received from the other communication device.

8. The communication device according to claim 7, wherein, after the period of unavailability has ended, the response frame to the retransmitted trigger frame is transmitted from the other communication device.

9. The communication device according to any one of claims 1 to 8, wherein if the other communication device does not set the unavailable period, the value of the second field of the response frame is set to a second specific value.

10. The communication device according to claim 9, wherein the second specific value is 0.

11. The communication device according to claim 1, wherein if the start time of the unavailable period is undetermined in the other communication device, the value of the first field is set to a third specific value.

12. The communication device according to claim 11, further comprising control means for performing communication control that restricts communication with other communication devices during the unavailable period based on information contained in the response frame, wherein the control means repeatedly retransmits the trigger frame up to a maximum time which is the upper limit that can be set for the first field if the third specific value is set for the first field of the response frame.

13. In the case of the other communication device, if the unavailability period occurs but the start time and length are undetermined, the value of the first field is set to a third specific value and the value of the second field is set to the specific value, the communication device according to claim 1.

14. The communication device according to any one of claims 11 to 13, wherein the third specific value is the maximum value among the values ​​that can be set in the first field.

15. The communication device according to claim 1, wherein the trigger frame is a Buffer Status Report Pol (BSRP) trigger frame, and the response frame is a Multi-STA Block Ack (M-BA) frame.

16. A communication device conforming to the IEEE 802.11 standard, comprising: receiving means for receiving a trigger frame from another communication device for requesting notification of a period of unavailability of communication in the communication device, which is used to restrict communication with the communication device; and transmitting means for transmitting a response frame to the other communication device, which includes a first field storing a value corresponding to the start time of the unavailability period and a second field storing a value corresponding to the length of the unavailability period, wherein if the length is undetermined or exceeds a maximum length which is an upper limit that can be set for the second field, the value of the second field is set to a specific value.

17. A control method for a communication device compliant with the IEEE 802.11 standard, comprising: transmitting a trigger frame to another communication device for requesting notification of a period of unavailability of communication in that other communication device, which is used to restrict communication with the other communication device; and receiving a response frame from the other communication device for the trigger frame, the response frame comprising a first field storing a value corresponding to the start time of the unavailability period and a second field storing a value corresponding to the length of the unavailability period, wherein the value of the second field is set to a specific value if the length is undetermined or exceeds a maximum length which is an upper limit that can be set for the second field.

18. A control method for a communication device compliant with the IEEE 802.11 standard, comprising: receiving a trigger frame from another communication device for requesting notification of a period of unavailability of communication in the communication device, which is used to restrict communication with the communication device; and transmitting a response frame to the other communication device, the response frame comprising a first field storing a value corresponding to the start time of the unavailability period and a second field storing a value corresponding to the length of the unavailability period, wherein if the length is undetermined or exceeds a maximum length which is an upper limit that can be set for the second field, the value of the second field is set to a specific value.

19. A program for causing a computer provided in a communication device compliant with the IEEE 802.11 standard to execute the control method described in claim 17 or 18.

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