Communication device, control method, and program

Abstract

This communication device functions as an access point conforming to the IEEE 802.11 standard in which a mode for periodically restricting communication is implemented. When the communication device forms one or more basic service sets (BSSs) and enables the mode in a state in which a plurality of BSSs including a first BSS and a second BSS are formed, the communication device transmits, in the first BSS, a wireless frame that includes at least information specifying a first period in which communication is periodically restricted in the first BSS, and that can specify a second period in which communication is periodically restricted in the second BSS, the second period at least partially overlapping the first period.

Description

Communication device, control method, and program

[0001] The present disclosure relates to a technique for improving the efficiency of communication in a wireless LAN.

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

[0003] Laurent Carion et al., "PDT MAC Coexistence", 2024

[0004] In the IEEE 802.11bn standard, the introduction of an operation mode called Periodic Unavailability Operation (PUO) mode, in which a period during which communication cannot be performed periodically is set, is being considered (see Non-Patent Document 1). Non-Patent Document 1 describes that, during the period when a station (STA) operating in the PUO mode cannot perform communication, the access point (AP) does not transmit data addressed to that STA. In the future, it is expected that the AP will also operate in the PUO mode in order to suppress the power consumption of the AP. However, since the role of the AP is different from that of the STA, the PUO mode cannot be applied to the AP in the same way as to the STA.

[0005] The present disclosure provides a technique for efficiently operating an AP in a Periodic Unavailability Operation (PUO) mode.

[0006] A communication device according to one aspect of the present disclosure is a communication device that functions as an access point compliant with the IEEE 802.11 standard, which implements a mode in which communication is periodically restricted, and comprises forming means for forming one or more Basic Service Sets (BSS), and transmitting means for transmitting a wireless frame in the first BSS that, when the mode is enabled in a state in which a plurality of BSSs including a first BSS and a second BSS are formed, includes at least information specifying a first period in which communication is periodically restricted in the first BSS, and can identify a second period in the second BSS in which communication is periodically restricted, the second period overlapping with the first period in at least a portion thereof.

[0007] According to the disclosed technology, the AP can be efficiently operated in Periodic Unavailability Operation (PUO) mode.

[0008] 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.

[0009] The attached drawings are included in the specification and constitute part thereof, illustrating embodiments in this disclosure and used to explain the technical ideas derived from this disclosure together with their descriptions. Figure 1 is a diagram showing an example configuration of a wireless communication system. Figure 2 is a diagram showing an example hardware configuration of a communication device operating as an AP. Figure 3 is a diagram showing the functional configuration of a communication device operating as an AP. Figure 4 is a diagram showing an example of the processing flow performed by the communication device. Figure 5 is a diagram showing an example configuration of a wireless frame transmitted by the communication device. Figure 6 is a diagram showing an example configuration of an element containing PUO setting information. Figure 7 is a diagram showing an example of the processing flow performed by the communication device.

[0010] 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.

[0011] (System Configuration) Figure 1 shows an example of the configuration of a wireless communication system according to this embodiment. 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 stands for Institute of Electrical and Electronics Engineers. Figure 1 shows a state where there are access points (AP101) and stations (STA121, STA122, and STA123) as communication devices, but this is only an example. That is, the number of STAs may be one or two, and the number of APs and STAs may be more. AP101 is assumed to implement two (or more) AP functions that are physically separate, or physically identical but logically separate, as shown, for example, AP A111 and AP B112. AP A111 and AP B112 are configured to form separate networks (Basic Service Sets (BSS)) and communicate with STAs connected to those networks. STAs may connect to either the first BSS formed by AP A111 or the second BSS formed by AP B112, or to both. This configuration, where multiple networks are formed by a single AP (communication device), is sometimes called a Co-located BSSID set. BSSID stands for BSS Identifier.

[0012] In this embodiment, the AP is configured to operate in Periodic Unavailability Operation (PUO) mode. When the AP operates in PUO mode, a period of a certain length during which communication is periodically unavailable (hereinafter referred to as the "no-communication period") is set. This no-communication period may be called a Service Period (SP). During the SP, the AP operating in PUO mode does not communicate with any connected STAs. This reduces the power consumption of the AP, or allows the AP to perform other operations during the SP, such as communication using another standard that may interfere with BSS communication within 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).

[0013] When an AP forms multiple BSSs (in the case of a Co-located BSSID set), a separate SP can be set for each BSS. This allows the AP to reduce power consumption by turning off communication circuits between SPs, or to perform processing such as communication using other communication standards, for example, when a separate physical AP is provided for each BSS. However, there are various forms of Co-located BSSID sets, and a single physical AP may be configured for multiple BSSs. For example, a Co-located BSSID set in which an AP uses a common frequency channel across multiple BSSs may be called a Co-hosted BSSID set or Multiple BSSID set. Note that a common frequency channel can be determined to be used when the Operating class and channel of multiple BSSs are common. In a Co-hosted BSSID set, Beacon frames and Probe Response frames are transmitted separately for each BSS. On the other hand, in a Multiple BSSID set, Beacon frames and Probe Response frames containing information about multiple BSSs are transmitted for a single BSS. In the following, the function that forms multiple BSSs under the conditions of a Multiple BSSID set may be referred to as the Multiple BSSID function. For example, if different SPs are set for each BSS in a Co-hosted BSSID set, the AP may not be able to turn off its communication circuit even if an SP is set for one BSS, because the SP period is outside for other BSSs. As a result, the AP may not be able to suppress power consumption or perform communication using other standards that may interfere with the BSS within the AP.

[0014] In this embodiment, in view of these circumstances, we provide a technology that enables an AP forming multiple BSSs to appropriately set SPs in PUO mode in those multiple BSSs. That is, for example, when an AP forms multiple BSSs using one communication circuit (common antenna connector), it can ensure that the SPs in PUO mode match in those multiple BSSs. Also, for example, when multiple BSSs formed using one communication circuit use a common frequency channel (common operating class and channel), the AP can ensure that the SPs in PUO mode match in those multiple BSSs. Below, we will describe the configuration and processing flow of a communication device that functions as an AP to efficiently perform such processing.

[0015] (Device Configuration) Figure 2 shows an example of the hardware configuration of a communication device that functions as an AP in this embodiment. As an example of its hardware configuration, the communication device includes, 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.

[0016] The storage unit 201 is configured to include one or more memories such as ROM and RAM. The storage unit 201 stores various information such as computer programs for performing the various operations described later, and communication parameters for wireless communication. ROM stands for Read Only Memory, and RAM stands for Random Access Memory. In addition to memories such as ROM and RAM, the storage unit 201 may also be configured to include storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs. Furthermore, the storage unit 201 may be configured to include multiple storage media such as memories.

[0017] The control unit 202 is configured to include, for example, one or more processors such as a CPU and an MPU. CPU stands for Central Processing Unit, and MPU stands for Micro Processing Unit. The control unit 202 controls the entire communication device by executing a computer program stored in the memory unit 201. The control unit 202 may also control the entire device through cooperation between the computer program stored in the memory unit 201 and the operating system. Furthermore, the control unit 202 generates data and signals (wireless frames) to be transmitted in communication with other communication devices. The control unit 202 may also include multiple processors, such as a multi-core processor, and perform various controls using these multiple processors. Additionally, the control unit 202 may include, for example, an ASIC (Application-Specific Integrated Circuit), a DSP (Digital Signal Processor), or an FPGA (Field-Programmable Gate Array).

[0018] Furthermore, the control unit 202 controls the functional unit 203 to perform predetermined processes such as wireless communication, imaging, printing, and projection. The functional unit 203 is configured to include 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 prints, for example, image data acquired via the communication unit 206. If the communication device is a scanner, the functional unit 203 is a reading device and outputs the scanned image data to the outside, for example, via the communication unit 206. If the communication device is a camera, the functional unit 203 is configured to include an image sensor and a lens and outputs the image data captured by the camera to the outside, for example, via the communication unit 206. The functional unit 203 may also include configurations for realizing AP (Application Platform) functions.

[0019] The input unit 204 is configured to include, for example, a touch panel, hard keys, buttons, etc., and accepts various operations from the user. The output unit 205 is configured to include a display, speaker, etc., and provides various outputs to the user. Here, the output from the output unit 205 can be a screen display output on the display or an audio output from the speaker. The output unit 205 may also include a vibrator and output information by vibration output. Note that both the input unit 204 and the output unit 205 may be implemented in a single module, such as a touch panel display. The input unit 204 and the output unit 205 may 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.

[0020] The communication unit 206 performs control for wireless communication compliant with the IEEE 802.11 series standard. The communication unit 206 can perform control of wireless communication compliant with, for example, the IEEE 802.11bn standard, its successor standards, or earlier legacy standards, as well as control of 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 communicates data such as image data, document data, and video data with a partner device via the communication unit 206. If the communication device supports standards other than the IEEE 802.11 series standard, such as NFC or Bluetooth®, the communication unit 206 may perform control of wireless communication compliant with these communication standards. Furthermore, if the communication device is capable of performing wireless communication compliant with multiple communication standards, separate communication units and antennas corresponding to those communication standards may be provided.

[0021] 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, respectively. Antenna 207 may also be configured to enable communication in the same frequency band. In this case, antenna 207 may be, for example, a multiband antenna capable of communication in multiple frequency bands. Figure 2 shows an example where the communication device has only one antenna, but multiple antennas may be used, for example, 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.

[0022] Figure 3 shows an example of the functional (software) configuration of a communication device that functions as an AP in this embodiment. The communication device is configured to include, 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 PUO control unit 306. Note that this functional configuration is just an 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.

[0023] The wireless LAN control unit 301 controls wireless LAN communication. The wireless LAN control unit 301 controls the communication unit 206 and antenna 207 in order to send and receive wireless signals with other communication devices that are 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.

[0024] The frame generation unit 302 generates wireless frames such as control frames, management frames, and data frames. Each wireless frame includes a MAC frame. MAC stands for Medium Access Control. A MAC frame is also called a MAC Protocol Data Unit (MPDU) or Aggregate MAC Protocol Data Unit (A-MPDU). 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 the 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. The frame analysis unit 303 analyzes the 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.

[0025] 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 the 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 sound. 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. The storage control unit 305 controls the storage unit 201 to perform various information storage controls, such as saving, searching, and extracting programs and data on which the communication device operates. The PUO control unit 306 performs control processing for the communication device to operate in PUO mode.

[0026] (Communication Flow) Figure 4 shows an example of the processing flow performed by a communication device functioning as an AP according to this embodiment. In Figure 4, the communication device enables operation in PUO mode (S401) and determines whether it is currently forming two or more BSSs (S402). If the communication device determines that it is forming two or more BSSs (YES in S402), it determines PUO setting information for each BSS (S403). At this time, if the communication device is forming multiple BSSs using a common physical configuration (communication circuit), it may determine the PUO setting information so that the silence periods (SP) in each BSS are the same. Note that PUO setting information so that the silence periods in each BSS are the same may only be determined if multiple BSSs are formed using a common physical configuration (communication circuit) and a common frequency channel is used in those multiple BSSs. In other words, even if the communication device is forming multiple BSSs using a common physical configuration (communication circuit), if the frequency channels used in those multiple BSSs are different, it may determine the PUO setting information for each BSS independently. Furthermore, if the communication device forms multiple BSSs using separate physical configurations (communication circuits), it may determine the PUO setting information for each BSS independently of each other. If the communication device determines that it forms only one BSS (NO in S402), it determines the PUO setting information for that BSS (S404). The communication device then generates and transmits a wireless frame containing all the PUO setting information determined in S403 or S404 (S405).

[0027] In this embodiment, as an example, if there are multiple BSSs operating in PUO mode, the communication device transmits the S405 wireless frame in only one of the multiple BSSs. This can be implemented by utilizing the mechanism in which Beacon frames and Probe Response frames are transmitted in only one BSS in the case of the Multiple BSS set described above. That is, the communication device may transmit PUO setting information for each of the multiple BSSs in a Beacon frame or Probe Response frame, for example. Alternatively, the communication device may transmit multiple PUO setting information in other Management frames such as Association Response frames, Re-association Response frames, and Action frames. Furthermore, PUO configuration information for each of the multiple BSSs may be included in various wireless frames, such as trigger frames and control frames like Multi-User-Request To Send (MU-RTS) frames.

[0028] Furthermore, PUO configuration information can be notified using, for example, the conventional Target Wake Time (TWT) mechanism. TWT is a mechanism in which the AP specifies the time (TWT) at which the STA should start up, and the STA starts up according to the notified TWT and transmits and receives signals while it is running. In this embodiment, PUO configuration information is notified using a variation of the TWT element used to notify configuration information related to the conventional TWT. Note that this is just one example, and PUO configuration information may be notified to the STA in any format that can notify each of the information described later. That is, the information element described below as "TWT element" is merely an example in terms of both its name and content, and may be replaced with information elements with other names and content. For example, below, each element and field related to PUO will be described in the context of In-Device Coexistence (IDC). Therefore, a TWT element may also be called an IDC element. That is, in a conventional TWT element, the name may be changed from TWT element to IDC element by setting a specific field to a specific value. Also, this element may be called an IDC TWT element to indicate that it is an element relating to both TWT and IDC. Note that the elements and fields in the frame described below are examples, and some may be omitted, or additional fields may be provided. The names and order of elements and fields may also be changed.

[0029] Figure 5 shows an example of the configuration of a wireless frame (MAC frame) transmitted from a communication device functioning as an AP in this embodiment. The MAC frame in this embodiment includes a TWT element 501 to which this wireless frame is transmitted. The BSSID of the BSS to which this wireless frame is transmitted may be called a Transmitted BSSID. A BSSID of a BSS to which this wireless frame is not transmitted, but whose information is transmitted in another BSS, may be called a Nontransmitted BSSID. That is, this wireless frame is transmitted in the BSS with a Transmitted BSSID, and not in the BSS with a Nontransmitted BSSID. The information regarding the Nontransmitted BSSID is included in this wireless frame and transmitted in the BSS with a Transmitted BSSID. Information regarding Nontransmitted BSSIDs is transmitted in Multiple BSSID element 502.

[0030] Multiple BSSID element 502 includes an Element ID field 511 set to "71" to indicate that this element is a Multiple BSSID element. The Length field 512 indicates the size of this element, and the MaxBSSID Indicator field 513 indicates the number of Nontransmitted BSSIDs for which information is provided in this element. Multiple BSSID element 502 also includes the number of Nontransmitted BSSID Profile subelements indicated by the MaxBSSID Indicator field 513. This element is transmitted when at least one Nontransmitted BSSID exists, and therefore includes at least one Nontransmitted BSSID Profile subject 514. Furthermore, if multiple Nontransmitted BSSIDs exist, this element includes a Nontransmitted BSSID Profile subject 515 corresponding to each BSSID. This element may also include a Vendor Specific subject that stores vendor-specific information.

[0031] Nontransmitted BSSID Profile subelement 514 and Nontransmitted BSSID Profile subelement 515 include a Subelement ID field set to "0". Setting the Subelement ID field to "0" indicates that this subelement is a Nontransmitted BSSID Profile subelement. The Length field 522 indicates the length of the subelement, and the Data field 523 contains information specific to that subelement. The Data field 523 contains various information about the BSS of the Nontransmitted BSSID. For example, the BSSID capability (Nontransmitted BSSID Capability) and the Service Set ID (SSID) are included in the Data field 523. Within this Data field 523, the TWT element 531 related to the Nontransmitted BSSID is included. In this embodiment, the STA obtains the PUO setting information for the Transmitted BSSID using the TWT element 501 described above, and obtains the PUO setting information for the Nontransmitted BSSID using the TWT element 531. Note that there may be cases where an element for the Nontransmitted BSSID does not exist, but an element for the Transmitted BSSID does exist. In this case, the settings shown in the elements of the Transmitted BSSID may be inherited in the Nontransmitted BSSID. That is, the Nontransmitted BSSID Profile subject may include information specific to the Nontransmitted BSSID and may not include information common to the Transmitted BSSID. Note that this is just an example, and the Nontransmitted BSSID Profile subject may include information common to the Transmitted BSSID.

[0032] Figure 6 shows a modified configuration of a TWT element used as an element for transmitting PUO setting information in this embodiment. This element stores "216" in the Element ID field 601, which indicates a TWT element. The TWT element shown in Figure 6 is also called a Broadcast TWT element. A Broadcast TWT element is a TWT element in which the Negotiation Type field 611 contained in the Control field 602 within this element is set to "2" or "3". In other words, the Negotiation Type field 611 is the 2nd and 3rd bits of the 0th to 7th bits of the Control field 602, and when the 2nd bit is "1", it becomes a Broadcast TWT element. This 2nd bit may also be called the Broadcast field. In the following, if it is an element for transmitting PUO configuration information, the Negotiation Type field 611 will be set to "2". Thus, an element for transmitting PUO configuration information according to this embodiment may be defined as an element based on a Broadcast TWT element.

[0033] The Control field 602 further includes a Wake Duration Unit field 612. In one example, this Wake Duration Unit field 612 may be read as the IDC Duration Unit field. The Wake Duration Unit field 612 stores information about the unit for indicating the length of the non-communication period (SP) by the PUO. In the Wake Duration Unit field 612, for example, storing "0" specifies the SP in units of 256 microseconds, and storing "1" specifies the SP in units of 1024 microseconds (= 1 Time Unit).

[0034] The element for transmitting PUO configuration information includes a Broadcast TWT Parameter Set field 603. The Broadcast TWT Parameter Set field 603 may, in one example, be called the IDC Parameter Set field. The Broadcast TWT Parameter Set field 603 includes a Request Type field 621. The Broadcast TWT Parameter Set field 603 also includes a Target Wake Time field 622 and a Nominal Minimum TWT Wake Duration field 623. Furthermore, the Broadcast TWT Parameter Set field 603 includes the TWT Wake Interval Mantissa field 624 and the Broadcast TWT Info field 625. The Target Wake Time field 622 may also be called the IDC Start Time field. The Nominal Minimum TWT Wake Duration field 623 may also be called the IDC Duration field. The TWT Wake Interval Mantissa field 624 may also be called the IDC Duration field. The Broadcast TWT Info field 625 may also be called the IDC Info field.

[0035] The Request Type field 621 includes the Broadcast TWT Recommendation field 631 and the TWT Wake Interval Exponent field 632. The Broadcast TWT Recommendation field 631 may also be called, for example, the Broadcast TWT / IDC Recommendation field. Setting the Broadcast TWT Recommendation field 631 to a previously unused value, such as "5", indicates that this element carries information related to IDC (PUO configuration information). When the Broadcast TWT Recommendation field 631 is set to "5", it may indicate that this element corresponds to any operation in which communication is not possible. If it is necessary to subdivide the operations that cannot perform this communication, the Broadcast TWT Recommendation field 631 may be set to "6" or "7" to indicate that it is an element related to the PUO mode. Alternatively, the type of element may be identified by other information. In this embodiment, an element in the Broadcast TWT element format in which the Broadcast TWT Recommendation field 631 is set to a predetermined value such as "5" is assumed to be an element related to PUO setting information. As described above, for example, the Element ID field 601 is set to "216" and the Negotiation Type field 611 is set to "2".

[0036] These fields are used to identify the period of silence (SP) in PUO mode. For example, a period of time in the unit specified in the Wake Duration Unit field 612 and with a duration indicated by the Nominal Minimum TWT Wake Duration field 623 is identified as the SP. The period of arrival of the SP is identified by the values ​​of the TWT Wake Interval Mantissa field 624 and the TWT Wake Interval Exponent field 632. For example, if the value of the TWT Wake Interval Mantissa field 624 is "m" and the value of the TWT Wake Interval Exponent field 632 is "n", the period is m × 2 n This is calculated. In addition, the Target Wake Time field 622 provides information that allows for the identification of the first SP (PUO operation start timing).

[0037] The Broadcast TWT Info field 625 includes the Unavailable BW field 641, the Unavailable BW index field 642, and the Broadcast TWT ID field 643. The Broadcast TWT Info field 625 also includes the MAX MCS field 644 and the MAX Nss field 645. Operation in PUO mode may, but is not limited to, a state of no communication between SPs; for example, the available communication parameters may be restricted. For example, if the available frequency bandwidth is restricted, the Unavailable BW field 641 may indicate information about the frequency bandwidth that becomes unavailable in an SP in PUO mode. Alternatively, instead of information about the frequency bandwidth that becomes unavailable, the information about the frequency bandwidth that is available in PUO mode may be indicated. The Unavailable BW index field 642 may store information indicating the location of the usable frequency band when the available frequency bandwidth is limited. For example, a combination of the Unavailable BW field 641 and the Unavailable BW index field 642 may indicate primary 80 MHz, secondary 80 MHz, primary 160 MHz, etc. In this case, the Unavailable BW index field 642 may indicate primary with "0" and secondary with "1".

[0038] The Broadcast TWT ID field 643 is set to, for example, "0". This indicates that this Broadcast TWT element is an element corresponding to all STAs belonging to the BSS associated with this TWT element. For example, by setting the Broadcast TWT ID field 643 of TWT element 501 to "0", all STAs belonging to the BSS of the Transmitted BSSID can acquire information such as SP in PUO mode. Also, by setting the Broadcast TWT ID field 643 of TWT element 531 to "0", all STAs belonging to the BSS of the Nontransmitted BSSID can acquire information in PUO mode. The MAX MCS field 644 stores a value that specifies the range of Modulation and Coding Schemes (MCS) available during the SP. MCSs are predefined and associated with indexes, and the value stored in the MAX MCS field 644 indicates that only MCSs corresponding to that value or smaller indexes are available during the SP. The MAX Nss field 645 stores a value indicating the maximum number of spatial streams available during the SP.

[0039] The communication device operating as an AP in this embodiment sets the values ​​of each field of the TWT element in Figure 6 in TWT element 501 and TWT element 531 so that SPs are set for the same period in multiple BSSs. For example, the same values ​​are set in the TWT Wake Interval Mantissa field 624 and the TWT Wake Interval Exponent field 632 in TWT element 501 and TWT element 531. In this case, the same values ​​may also be set in the Wake Duration Unit field 612, the Target Wake Time field 622, and the Nominal Minimum TWT Wake Duration field 623. Furthermore, in one example, the TWT element may be omitted for Nontransmitted BSSIDs, and the TWT element of the Transmitted BSSID may be inherited. That is, for Nontransmitted BSSIDs, the SP in PUO mode may be explicitly indicated, or the wireless frame may be configured so that the SP in PUO mode can be implicitly identified. Note that SPs in multiple BSSs do not necessarily have to be exactly the same, and an SP in one BSS may be configured to encompass an SP in another BSS. This allows for the configuration of SPs so that, for example, no communication occurs during the SP period in the BSS that encompasses the SP, thus preventing interference with communication of other wireless communication standards within the device. Also, in the BSS that encompasses the SP of another BSS, especially when multiple BSSs are implemented with different physical configurations, power consumption can be reduced by turning off the power to the communication circuit during periods when no communication is taking place. Furthermore, the SPs in multiple BSSs may be set to match in at least a portion of them. In this case, the SPs may be set so that the time length of the overlapping portion of the SPs is greater than or equal to a predetermined value. Alternatively, the SPs may be set so that the time length of the overlapping portion of the SPs is greater than or equal to a predetermined ratio to the total time length of the SPs.

[0040] In this way, when an AP enables PUO mode while multiple BSSs are formed, it can appropriately set the SP for PUO mode and notify the STAs connected to each BSS of the period of no communication (or period of restricted communication). The SP for PUO mode may be set, for example, in response to requests from STAs belonging to each BSS. That is, the AP may decide the SP independently, or the SP may be set based on requests from STAs connected to the AP. If the AP is requested by multiple STAs to set different periods as SPs and cannot appropriately set the SP, it may disable PUO mode or reject the requests from at least some of the STAs.

[0041] Furthermore, the AP can generate and transmit a similar frame when adding a BSS while operating in PUO mode. An example of the processing flow in this case is shown in Figure 7. In this example, the communication device, which functions as an AP, determines whether to add a second BSS (S702) while the PUO mode is enabled in the first BSS. If the communication device decides to add a second BSS (YES in S702), it determines whether there is a request for PUO setting information such as SP from the STA belonging to the second BSS (S703). If there is a request for PUO setting information (YES in S703), the communication device updates the PUO setting information of the first BSS according to the request, so that the SPs of the PUO mode of the first BSS and the second BSS match (or one of them is included in the other) (S704). On the other hand, if there is no request for PUO setting information (NO in S703), the communication device uses the PUO setting information of the first BSS as the PUO setting information of the second BSS (S705). Then, the communication device transmits a radio frame containing the PUO setting information for the first and second BSS determined as in S704 or S705 (S706). The structure of this radio frame is as described above, so it will not be explained again here.

[0042] As described above, even when the AP adds a BSS while the Puo mode is enabled, the AP can appropriately set the SP in the Puo mode and notify the STAs connected to each BSS of the communication-free period (or the period during which communication is restricted).

[0043] Note that any of the above-described embodiments can be used in combination. In the above example, the case where the processing is performed so that the SPs in the Puo mode are common in a plurality of BSSs has been described. However, the SPs in the Puo mode may be made common only in some of the plurality of BSSs. For example, when the AP has a plurality of physical communication circuits and one or more BSSs are formed in each communication circuit, the above-described processing may be performed for each communication circuit. That is, control such as not performing the above-described processing in one communication circuit while performing the above-described processing in another communication circuit may be performed. Further, for example, in the context of an IDC, the above-described processing may be performed only in a frequency band that can interfere with communication in another wireless communication standard during a period of communication in another wireless communication standard different from the IEEE 802.11 standard. For example, when the AP forms a plurality of BSSs in each of the 2.4 GHz and 5 GHz frequency bands (for example, using the Multiple BSSID function) and performs Bluetooth (registered trademark) communication, the above-described processing may be performed only at 2.4 GHz.

[0044] The present disclosure can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and causing one or more processors in the computer of the system or device to read and execute the program. It can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

[0045] The technical idea derived from the present disclosure is not limited to the disclosed exemplary embodiments, and is intended to include various modifications to the exemplary embodiments, or substitutions by equivalent structures or functions. The scope of the following claims should be given the broadest interpretation so as to include all such modifications and equivalent structures and functions.

[0046] This application claims priority based on Japanese Patent Application No. 2025-024488, filed on 18 February 2025, and all of its contents are incorporated herein by reference.

Claims

1. A communication device that functions as an access point compliant with the IEEE 802.11 standard, which implements a mode in which communication is periodically restricted, comprising: forming means for forming one or more Basic Service Sets (BSS); and transmitting means for transmitting a wireless frame in the first BSS that, when the mode is enabled in a state in which a plurality of BSSs including a first BSS and a second BSS are formed, includes at least information specifying a first period in which communication is periodically restricted in the first BSS, and that can identify a second period in the second BSS in which communication is periodically restricted, the second period which overlaps with the first period in at least a part.

2. The communication device according to claim 1, wherein the wireless frame further includes information specifying the second period.

3. The communication device according to claim 2, wherein the wireless frame includes a Multiple BSSID element for transmitting information about the plurality of BSSs, and the information specifying the second period is transmitted via the Multiple BSSID element.

4. The communication device according to claim 1, characterized in that, when the first period and the second period coincide, the wireless frame does not include information specifying the second period, thereby inheriting the information specifying the first period as information specifying the second period.

5. The communication device according to any one of claims 1 to 4, characterized in that the first period is a period during which communication cannot be performed in the first BSS, and the second period is a period during which communication cannot be performed in the second BSS.

6. The communication device according to any one of claims 1 to 4, characterized in that the first period is a period during which the communication parameters that can be used in the first BSS are restricted, and the second period is a period during which the communication parameters that can be used in the second BSS are restricted.

7. The communication device according to claim 6, characterized in that the wireless frame includes communication parameters that can be used in the first BSS during the first period, and is generated in a way that allows for the identification of communication parameters that can be used in the second BSS during the second period.

8. The communication device according to claim 7, characterized in that the communication parameters include at least one of the following: frequency bandwidth, information indicating the location of the frequency bandwidth, range of Modulation and Coding Scheme (MCS), and maximum number of spatial streams.

9. The communication device according to any one of claims 1 to 8, characterized in that the wireless frame is at least one of a Beacon frame, a Probe Response frame, an Association Response frame, a Re-association Response frame, an Action frame, a Trigger frame, or a Multi User-Request To Send (MU-RTS) frame.

10. A control method performed by a communication device that functions as an access point compliant with the IEEE 802.11 standard, which implements a mode in which communication is periodically restricted, comprising: forming one or more Basic Service Sets (BSS); and, when the mode is enabled in a state in which a plurality of BSSs, including a first BSS and a second BSS, are formed, transmitting a wireless frame in the first BSS that can identify a second period in which communication is periodically restricted, which includes at least information specifying a first period in which communication is periodically restricted, and which overlaps with the first period in the second BSS by at least a portion thereof.

11. A program for causing a computer provided in a communication device that functions as an access point compliant with the IEEE 802.11 standard, which implements a mode in which communication is periodically restricted, to execute the control method described in claim 10.

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