Communication device, control method, and program

Abstract

This enables efficient operation of communication devices in communication systems that use communication links consisting of multiple channels. [Solution] A communication device compliant with IEEE 802.11 bonds a first channel with one or more second channels different from the first channel, and communicates using multiple communication methods, including a first communication method that uses the first channel for communication, and a second communication method that uses a third channel included in the second channel when the first channel cannot be used. The device acquires Target Wake Time Service Period (TWT SP) information set in the Overlapping BSS (OBSS) that uses the first channel, determines whether to use the second communication method for communication during the period in which the TWT SP is set based on the length of the set TWT SP, and sends a notification to other communication devices indicating that communication will be performed using the second communication method based on the determination result.

Description

Technical Field

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[0001] The present invention relates to data communication technology in a communication device capable of communicating using a communication link composed of a plurality of channels.

Background Art

[0002] In recent years, with the increase in the amount of data to be communicated, the development of communication technologies such as wireless LAN (Local Area Network) has been progressing. As the main communication standards for wireless LAN, the IEEE (Institute of Electrical and Electronic Engineers) 802.11 standard series is known. The IEEE 802.11 standard series includes IEEE 802.11a / b / g / n / ac / ax / be standards and the like. 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] As one of the candidate technologies included in the IEEE 802.11bn standard, a technology for efficiently using frequency resources in a communication method using one communication link composed of a plurality of channels has been studied. For example, in Patent Document 1, a technique for communicating using another channel included in the same communication link as the Primary Channel (PCH) when the PCH used to acquire the transmission right cannot be used is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] A communication device according to one aspect of the present invention is a communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, and includes a first communication method configured to enable communication by bonding a first channel with one or more second channels different from the first channel, the first communication method which acquires transmission rights and performs communication using the first channel, and a second communication method which, when the first channel cannot be used, acquires transmission rights using a third channel included in the second channel and performs communication using at least the third channel, and includes communication means for performing communication using a plurality of communication methods, the communication device according to one aspect of the present invention is a communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, and includes a first communication method which acquires transmission rights and performs communication using at least the third channel, when the first channel cannot be used, the communication device The system includes a determination means for determining whether or not to perform communication using the second communication method during the period in which SP is set, and a notification means for notifying the other communication device that communication using the second communication method will be performed based on the result of the determination. [Effects of the Invention]

[0007] According to the present invention, wireless resources can be efficiently utilized in a communication system that uses a communication link composed of multiple channels. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing an example configuration of a wireless communication system. [Figure 2]This is a schematic diagram showing an example of a time chart for when a communication device transmits data. [Figure 3] This figure shows an example of the hardware configuration of a communication device. [Figure 4] This figure shows an example of the AP's functional configuration. [Figure 5] This figure shows an example of the functional configuration of STA. [Figure 6] This figure shows an example sequence of events performed between AP and STA. [Figure 7] This figure shows an example of the configuration of a TWT element. [Figure 8] This figure shows an example of the configuration of the Control field. [Figure 9] This figure shows an example of the configuration of the TWT Parameter Information field. [Figure 10] This figure shows an example of the configuration of the TWT Parameter Information field. [Figure 11] This figure shows an overview of the method for determining whether or not communication using SP-based NPCA is possible. [Figure 12] This figure shows an overview of the method for generating integrated TWTs. [Figure 13] This figure shows an overview of the method for generating integrated TWTs. [Figure 14] This figure shows an example of a processing flow executed by the AP. [Figure 15] This figure shows an example of a processing flow executed by the AP. [Figure 16] This figure shows an example of the processing flow executed by STA. [Figure 17] This figure shows an example of the processing flow executed by STA. [Figure 18] This figure shows an example sequence of events performed between AP and STA. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] (System Configuration) FIG. 1 shows a configuration example of a wireless communication system according to this embodiment. The wireless communication system includes, for example, an access point (AP) 101, a station (STA) 111, and STA 112. The AP 101, the STA 111, and the STA 112 are communication devices capable of performing wireless communication compliant with the IEEE 802.11 standard series. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. FIG. 1 shows a configuration in which the STA 111 and the STA 112 participate in a network 121 provided by the AP 101. The network 121 may also be called a Basic Service Set (BSS). The BSS may refer to a set of communication devices including the AP 101 and the STAs participating in the network 121 provided by the AP 101, or may refer to the geographical range within which the AP 101 can communicate with the STAs participating in the network 121 provided by the AP 101. Also, the geographical range within which the AP 101 can communicate with the STAs participating in the network 121 provided by the AP 101 may be called a Basic Service Area (BSA). In the network 121 of FIG. 1, a configuration in which one AP 101, two STAs 111, and STA 112 are present is shown. However, for example, in the network 121, there may be a plurality of APs, and there may be one or three or more STAs. Also, in that case, each of the STAs may be connected to one AP, or one STA may be connected to a plurality of APs.

[0011] In Figure 1, near network 121, there are two networks: network 122, consisting of AP102, STA113, and STA114; and network 123, consisting of AP103, STA115, and STA116. AP101 is assumed to be communicably connected to AP102 via a Distribution System (DS) 141, which is configured as either a wired or wireless line. DS141 can be a wired communication line such as Ethernet® or a telephone line. Alternatively, DS141 can be a wireless communication line such as LTE (Long-Term Evolution) or WiMAX (Worldwide Interoperability for Microwave Access). DS141 may also be a wireless communication line compliant with the IEEE 802.11 standard series. Note that STAs participating in the BSS configured by AP101 may be connected to other BSSs or external networks via AP101 and DS141. On the other hand, there is no DS between AP101 and AP103, and AP101 is not connected to AP103. For example, AP101 cannot directly obtain information about network 123 from AP103. AP102 and AP103 are communication devices capable of performing wireless communication compliant with the IEEE 802.11 series standard, just like AP101. Similarly, STA113 to STA116 are communication devices capable of performing wireless communication compliant with the IEEE 802.11 series standard, just like STA111 and STA112. In each of networks 122 and 123, there may be multiple APs and one or more STAs. For AP101, STA111, and STA112, network 121 is the BSS to which their devices belong and can be called their own BSS. On the other hand, for AP101, STA111, and STA112, networks 122 and 123 are networks that can interfere with their own BSS and can be called Overlapping BSS (OBSS). For example, if OBSS covers at least a portion of the geographical area covered by its own BSS and is using PCH, interference with its own BSS may occur.This embodiment describes the operation of AP101, STA111, and STA112 in network 121. This operation is also applicable to the operation of AP102, STA113, and STA114 in network 122, and to the operation of AP103, STA115, and STA116 in network 123. STA111 and STA112 may be referred to as STA110 without distinction. Similarly, AP101 and STA110 may be referred to as communication device 100 without distinction.

[0012] In this embodiment, the communication device 100 is configured to execute a communication method compliant with the IEEE 802.11bn standard. The IEEE 802.11bn standard is the successor to the IEEE 802.11be standard, which aims for a maximum transmission speed of 46.08 Gbps (Gigabit per second). The main features of the IEEE 802.11bn standard are that it has functions that realize highly reliable communication, low latency communication, and improved throughput when communication traffic is congested. The wireless frame used in the communication method compliant with this standard may be called UHR (Ultra High Reliability) PPDU. PPDU is an abbreviation for PLCP Protocol Data Unit, and PLCP is an abbreviation for Physical Layer Convergence Protocol. Note that the names UHR and IEEE 802.11bn may be changed to other names when the standard is finalized. Furthermore, it should be noted that this specification and the claims attached herein are applicable to communication devices using all successor standards to IEEE 802.11be. Also, the communication device 100 may support at least one of the legacy standards that precede the IEEE 802.11bn standard. Legacy standards include, for example, the IEEE 802.11a / b / g / n / ac / ax / be standards. The communication device 100 may also support other communication standards such as Bluetooth®, NFC, UWB, ZigBee, and MBOA. UWB stands for Ultra Wide Band, and MBOA stands for Multi Band OFDM Alliance. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, etc. The communication device 100 may also support communication standards such as wired LAN. AP101 is, for example, a wireless LAN router or a personal computer (PC), but is not limited to these. AP101 may be an information processing device such as a wireless chip capable of performing wireless communication compliant with the IEEE 802.11bn standard.STA110 is a terminal device such as a wearable device like a camera, tablet, smartphone, PC, mobile phone, video camera, headset, smart glass, HMD (head-mounted display), etc., but is not limited thereto. STA110 may be an information processing device such as a wireless chip capable of performing wireless communication that supports transmission and reception of PPDU compliant with IEEE802.11bn standard or the like. In this case, various controls can be executed by a hardware circuit inside the wireless chip. In addition, various processes can also be executed by cooperation of a processor such as ASIP, memory, and hardware circuit inside the wireless chip. ASIP is an abbreviation for Application-specific instruction set processor.

[0013] The communication device 100 can communicate using radio signals in frequency bands such as the 2.4GHz, 3.6GHz, 5GHz, 6GHz bands, and millimeter wave bands such as the 45GHz and 60GHz bands. The frequency bands used by the communication device 100 are not limited to these, and may include, for example, the Sub1GHz band. Furthermore, the communication device 100 can communicate using bandwidths of 20MHz, 40MHz, 80MHz, 160MHz, 320MHz, 540MHz, 640MHz, 1080MHz, and 2160MHz. The bandwidths used by the communication device 100 are not limited to these, and may include, for example, 240MHz or 4MHz. Note that the IEEE 802.11 standard series specifies frequency channels using a 20MHz bandwidth as basic channels in frequency bands such as the 2.4GHz, 5GHz, and 6GHz bands. In addition, this standard defines multiple usable channels in each of the 2.4GHz, 5GHz, and 6GHz frequency bands. In this standard, the communication device 100 can use a predetermined channel in combination with other adjacent channels. This use of a predetermined channel in combination with other adjacent channels may be called channel bonding. A bundle of channels formed by one or two or more adjacent channels may be called a communication link. That is, one link formed by two channels with a bandwidth of 20 MHz may use a bandwidth of 40 MHz. For example, the IEEE 802.11be standard is expected to specify 320 MHz as the maximum bandwidth available in a single link. A link with a bandwidth of 320 MHz may be formed by 16 channels with a bandwidth of 20 MHz. Furthermore, signals transmitted in this bandwidth may be continuous or discontinuous on the frequency axis. AP101 and STA102 may be AP MLDs (Multi-Link Devices) and STA MLDs, respectively, that support Multi-Link, enabling communication by establishing multiple links simultaneously.

[0014] When the communication device 100 transmits a signal using a link established with another communication device, it performs carrier sensing to determine whether or not to transmit. Carrier sensing is the operation in which the communication device 100 determines whether or not there is a signal on the channel that it intends to use for transmission. For example, the communication device 100 measures the strength of the signal received on the channel (received signal strength) and determines that a signal exists if the received signal strength exceeds a predetermined threshold (physical carrier sensing). The received signal strength may also be called the Received Signal Strength Indicator (RSSI). The communication device 100 may also determine the presence or absence of a signal based on information such as the Duration field contained in the signal received on the channel (virtual carrier sensing). For example, the communication device 100 stores the period indicated by the Duration field contained in the received signal as a Network Allocation Vector (NAV) within itself. The communication device 100 can treat the stored NAV as a period during which it does not transmit. In this embodiment, the operation by which the communication device 100 sets a period during which it will not transmit based on information such as the Duration field of the received signal is called setting NAV. That is, until the NAV set on the channel expires, the communication device 100 determines that a signal is present on the channel. In this way, the communication device 100 determines whether or not a signal is present on the channel based on the results of performing physical carrier sensing and virtual carrier sensing. If the communication device 100 determines that a signal is present on the channel, it may determine that transmission is not possible. In this case, the state of the channel may be called a busy state. For example, if the same channel as the BSS is used in OBSS, the channel may become busy due to communication in OBSS. On the other hand, a state in which no signal is detected on the channel in carrier sensing and NAV is not set may be called an idle state. If the channel is in an idle state, the communication device 100 may determine that transmission is possible.

[0015] The communication device 100, for example, when communicating using a 160MHz bandwidth link, can determine whether transmission is possible using only the 20MHz bandwidth Primary Channel (PCH) included in that link. The PCH is one of the eight 20MHz bandwidth channels that make up the 160MHz bandwidth link. AP101 can notify STA110 of the PCH using a periodically broadcast Beacon frame. For example, the IEEE802.11 standard series states that the communication device 100 can start transmitting if it determines that transmission is possible as a result of performing carrier sensing on the PCH over a predetermined period. The predetermined period is determined by the Interframe Space (IFS) defined for each access category that classifies the type of communication traffic, and a random number (backoff counter) randomly determined from a predetermined range. In other words, if the communication device 100 determines that the PCH is idle over this predetermined period, it acquires the right to transmit using that link. Furthermore, if channels other than the PCH were idle during the PIFS period immediately preceding the start of transmission, the communication device 100 may perform transmission using channel bonding with the idle channel and the PCH. PIFS is an abbreviation for Priority Interframe Space. Also, if the communication device 100 determines that transmission is not possible as a result of carrier sensing on the PCH, it may postpone transmission even if other channels included in the same link are idle. Note that each channel other than the PCH that constitutes a single link may be called a non-primary channel (NPCH). A non-primary channel may also be called a secondary channel (SCH).

[0016] In communication device 100, if a signal is being received on a certain channel, and a signal is being transmitted on another channel (e.g., an adjacent channel) located at a frequency close to that channel, the received signal may not be properly received. For example, suppose communication device 100 can simultaneously perform transmission and reception using different channels. If communication device 100 is receiving on a certain channel and transmits on an adjacent channel, the power of the transmitted signal leaks into the channel of the received signal, causing interference to the received signal. Generally, the power due to such leakage of the transmitted signal is much greater than the received power of the received signal, so the received signal is not properly received. To avoid this situation, the IEEE 802.11 standard series provides a mechanism to prevent other communication devices from transmitting signals to a communication device using a channel adjacent to the PCH while that communication device is transmitting a signal. That is, a PCH is provided as a channel commonly used by communication devices to determine whether or not to transmit, and while one communication device is transmitting using the PCH, the other communication device is required not to transmit, even if other channels are idle. As a result, while a communication device is transmitting a signal and the PCH is in use, other communication devices will not transmit signals using channels adjacent to that PCH, thus preventing a situation where a communication device receives signals on those adjacent channels. Therefore, the interference problem caused by power leakage between channels mentioned above can be eliminated.

[0017] However, as the IEEE 802.11 standard series has expanded, the bandwidth used in a single link has increased, and as described above, communication methods that always use the PCH may not be able to use frequency resources efficiently. For example, if the PCH is busy, other idle channels (NPCHs) will not be used, which can hinder the efficient use of frequency resources for the entire link. Figure 2(A) shows an example of a time chart when STA102 transmits data to AP101. In Figure 2(A), STA102 performs carrier sensing on the PCH, confirms that it is idle, and then transmits data using the 20MHz bandwidth PCH. In this case, for example, even if the seven NPCHs other than the PCH are idle, other communication devices are not allowed to communicate using the NPCHs. Figure 2(B) shows another example of a time chart when STA102 transmits data to AP101. In Figure 2(B), while STA111 is performing carrier sensing on the PCH, another network geographically close to STA111 (for example, network 122 in Figure 1) is using the PCH. In this case, STA111 determines that the PCH is busy during carrier sensing, so even if the other seven NPCHs are idle, for example, STA111 is not allowed to communicate with AP101 using the NPCHs. However, since AP101 is not transmitting at this time, even if STA111 were to transmit to AP101 using the NPCHs, AP101 could properly receive the signal transmitted by STA111. Thus, if, for example, a 20MHz bandwidth PCH is being used by another network, the remaining 140MHz of idle NPCHs cannot be utilized, resulting in inefficient use of frequency resources.

[0018] In contrast, the communication device 100 may, based on the fulfillment of predetermined conditions, communicate between communication devices using NPCHs included in the same link as the PCH, without using the PCH itself. For example, the communication device 100 sets one or more channels among the NPCHs included in the same link as the PCH as a Secondary Primary Channel (SPCH). The SPCH is a channel used to acquire the right to transmit using the NPCH when the PCH is busy. The SPCH may be called by other names, for example, a Primary Secondary Channel (PSCH). If the communication device 100 determines that the PCH is being used by a communication device in another network (OBSS), it then determines whether transmission is possible on the SPCH. If it determines that transmission is possible on the SPCH, the communication device 100 transmits using one or more NPCHs, including the SPCH. As an example, the communication device 100 can determine whether the PCH is being used by a communication device in its own BSS or by a communication device in the OBSS by identifying the source of the signal being communicated on the PCH. Furthermore, the determination of whether or not the SPCH is transmittable can be performed in the same way as the determination of whether or not the PCH is transmittable as described above. In this embodiment, a communication method that transmits using one or more channels, including the SPCH, without using the PCH is called NPCH access (Non-Primary Channel Access). NPCH access may also be called NPCA. Note that this communication method may be called by other names. For example, this communication method may be called SCA (Secondary Channel Access). Thus, when the communication device 100 acquires the right to transmit using the first channel (PCH), it communicates using a first communication method configured to enable communication by bonding the first channel with one or more second channels (NPCH) different from the first channel. Note that in communication using the first communication method, the communication device 100 may communicate using only the PCH without using the NPCH.On the other hand, when predetermined conditions are met, the communication device acquires transmission rights using a third channel (SPCH) included in the second channel, without using the first channel, and communicates using a second communication method that uses at least the third channel. The second communication method includes NPCA. The predetermined conditions may be, for example, that the PCH is being used by OBSS and the SPCH is available. By configuring communication to use multiple communication methods including these, the communication device 100 can communicate efficiently by using NPCH, which has less impact on the PCH, even when the PCH is being used.

[0019] As described above, if the communication device 100 performs communication using NPCA even when the PCH is busy, frequency resources will be used efficiently. However, if each communication device 100 performs carrier sensing on the PCH and performs NPCA based on whether the PCH is being used by OBSS, communication using NPCA may fail depending on the geographical location of the communication devices 100. For example, depending on the geographical location of AP101 and STA110, a signal from OBSS may be received by one communication device but not by the other. In this case, even if the communication device that received the signal from OBSS performs NPCA using SPCH, communication using NPCA may fail because the other communication device is not receiving on SPCH. In such a situation, when communication using NPCA, the communication device 100 may exchange signals to confirm that the other communication device is receiving on SPCH before transmitting data. For example, communication device 100 can confirm that the other party's communication device is receiving on the SPCH by exchanging an Initial Control Frame (ICF) and an Initial Control Response (ICR), which is the response to the ICF. However, exchanging the ICF and ICR shortens the period available for communication using NPCA. In particular, when communication device 100 performs NPCA based on the fact that the PCH is being used by OBSS, overhead for the ICF and ICR occurs in addition to the carrier sense overhead on both the PCH and NPCH. This can reduce the efficiency of frequency resource utilization.

[0020] In light of these circumstances, the communication device 100 in this embodiment determines a period for communication using NPCA with the other party's communication device and performs communication using NPCA during that period. For example, the period during which the communication device 100 performs communication using NPCA with the other party's communication device is the period during which communication is scheduled to take place in OBSS. As an example, the IEEE 802.11 standard series specifies a function for setting a predetermined period during which the AP communicates with an STA that performs power-saving operation. An STA that performs power-saving operation enters an AWAKE state during the predetermined period set by the AP. An STA that performs power-saving operation may enter a DOZE state outside of the predetermined period set by the AP. The time during which the STA is in the AWAKE state is called the Target Wake Time (TWT). The period during which the STA maintains the AWAKE state is called the TWT Service Period (TWT SP). In this embodiment, setting the TWT means that the AP uses parameters such as TWT and TWT SP to set the period during which the STA connected to its device should be in the AWAKE state. Furthermore, the period during which the STA maintains the AWAKE state in a configured TWT is called the TWT SP, and the length of the TWT SP is called the TWT SP duration. In addition, information related to the configured TWT is called TWT information. TWT information may include the TWT SP duration, the start timing of the TWT SP, the interval between TWT SPs, and TWT identification information. In a BSS where a TWT is configured, intensive communication may occur between the STA and AP, which are operating in power-saving mode, during the TWT SP. For this reason, when a TWT is configured in an OBSS (network 122, etc.), the proportion of AP 101, STA 111, and STA 112 that can acquire transmission rights in the PCH may be lower during the periods corresponding to each TWT SP compared to other periods. Therefore, the communication device 100 may configure the period corresponding to the TWT SP of the TWT configured in the OBSS as the period during which it and the other party's communication device communicate using NPCA.The period during which communication is performed using NPCA may be called the NPCA Service Period (NPCA SP). This allows communication device 100 to switch to NPCA communication, omitting carrier sensing on the PCH during periods when it is difficult to acquire transmission rights on the PCH, thereby reducing the overhead equivalent to carrier sensing on the PCH. Furthermore, during NPCA SP, communication device 100 can exchange data by omitting the exchange of ICF and ICR, assuming that the other communication device is receiving on the SPCH. In addition, communication device 100 can avoid interfering with OBSS by not using the PCH during TWT SPs, when communication is concentrated in OBSS. The IEEE 802.11be standard is expected to define a function called Restricted TWT (R-TWT) for the communication of high-priority data such as low-latency traffic. By performing communication using NPCA during periods when R-TWT SPs are set in OBSS, communication device 100 can avoid interfering with high-priority traffic communication in OBSS.

[0021] The communication device 100 acquires information about the TWT set in OBSS and determines whether or not to use the second communication method (NPCA) for communication during the period set by the TWT SP, based on the duration of the TWT SP. The communication device 100 also sends a notification to the other party's communication device indicating that it will use the second communication method based on the result of the determination. For example, if the communication device 100 sets the period corresponding to the TWT SP of the TWT set in OBSS as the NPCA SP, if the duration of the TWT SP is short, communication may not be efficient. For example, if the duration of the TWT SP is shorter than the period required for the communication device 100 to communicate, the communication device 100 cannot complete the communication within the set NPCA SP. Furthermore, if a switching time occurs for the communication device 100 to switch from communication using the first communication method to communication using the second communication method, the period during which the communication device 100 can use communication will be further shortened. The communication device 100 compares the duration of the TWT SP in OBSS with a predetermined value to determine whether or not to perform communication using NPCA. If there is sufficient time to perform communication using NPCA, it can perform communication using NPCA. The communication device 100 can also identify the period for performing communication using NPCA (NPCA SP) based on the TWT SP set in OBSS and notify the other communication device. The communication device 100 and the other communication device can start communication using NPCA without attempting to acquire transmission rights using PCH at the NPCA SP. In this embodiment, the method of performing communication using NPCA by defining an NPCA SP between communication devices will be called SP-based NPCA. The method in which each communication device performs carrier sensing of PCH and autonomously determines whether or not to perform communication using NPCA based on the result will be called TXOP-based NPCA. TXOP is an abbreviation for Transmission Opportunity. These NPCA methods may be called by other names. An example configuration and processing of the communication device 100 operating as described above will be explained below.

[0022] (Device configuration) Figure 3 shows an example of the hardware configuration of the communication device 100 in this embodiment. As an example of its hardware configuration, the communication device 100 includes, for example, a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 306, and an antenna 307. The communication device 100 may have multiple antennas.

[0023] The storage unit 301 is composed of one or more memories, including ROM and RAM, and may store control programs for various operations of each functional unit constituting the communication device 100, as well as various information such as parameters for communication. ROM and RAM are abbreviations for Read Only Memory and Random Access Memory, respectively. In addition to memories such as ROM and RAM, the storage unit 301 may also be composed of 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.

[0024] The control unit 302 is composed of one or more processors, such as a CPU and an MPU, and controls the entire communication device 100 by executing a control program stored in the memory unit 301. Alternatively, the control unit 302 may control the entire communication device 100 through cooperation between the control program stored in the memory unit 301 and the OS (Operating System). CPU and MPU are abbreviations for Central Processing Unit and Micro Processing Unit, respectively. If the control unit 302 has multiple processors, such as a multi-core processor, it may be configured so that the entire communication device 100 is controlled by multiple processors.

[0025] Furthermore, the control unit 302 controls the functional unit 303 to perform predetermined processes such as communication, imaging, printing, and projection. The functional unit 303 is hardware that enables the communication device 100 to perform the predetermined processes described above. For example, if the device is a camera, the functional unit 303 is the imaging unit and performs imaging processing. Also, for example, if the device is a printer, the functional unit 303 is the printing unit and performs printing processing. Also, for example, if the device is a projector, the functional unit 303 is the projection unit and performs projection processing.

[0026] The input unit 304 receives various operations from the user. The output unit 305 outputs various information to the user via a monitor screen or speaker. The output from the output unit 305 may be a display on the monitor screen, audio output via a speaker, vibration output, etc. The input unit 304 and the output unit 305 may both be implemented in a single module, such as a touch panel. The input unit 304 and the output unit 305 may each be an integrated device with the communication device 100, or they may be separate devices.

[0027] The communication unit 306 controls wireless communication compliant with the IEEE 802.11bn standard. In addition to the IEEE 802.11bn standard, the communication unit 306 may also control wireless communication compliant with other IEEE 802.11 standard series, such as legacy standards. The communication unit 306 controls the antenna 307 to transmit and receive signals for wireless communication generated by the control unit 302. The communication unit 306 is a so-called wireless chip and may itself include one or more processors and memory. If the communication device 100 supports other wireless communication standards such as NFC and Bluetooth, or wired communication such as wired LAN, in addition to the IEEE 802.11bn standard, the communication unit 306 may control communication compliant with these communication standards. Furthermore, if the communication device 100 can perform wireless communication compliant with multiple communication standards, the communication device 100 may have separate communication units and antennas corresponding to each communication standard. The communication device 100 communicates data with the other communication device via the communication unit 306. The antenna 307 may be configured separately from the communication unit 306, or it may be configured as a single module together with the communication unit 306. If the communication device 100 is configured to perform carrier sensing of multiple SPCHs simultaneously, the communication device 100 may be provided with the necessary number of communication units 306 for that purpose.

[0028] Antenna 307 is an antenna capable of communication in the 2.4GHz band, 5GHz band, 6GHz band, and millimeter wave bands such as 45GHz and 60GHz. Figure 3 shows a configuration in which the communication device 100 has two antennas 307, but the communication device 100 may have one or more antennas, and may have one or more antennas for each frequency band that the device can use. Also, if the communication device 100 has multiple antennas, the communication device 100 may have a communication unit 306 for each antenna. Antenna 307 may be physically composed of two or more antennas in order to realize (Multi-Input and Multi-Output) transmission and reception.

[0029] (Functional Configuration) Figure 4 shows an example of the functional configuration of AP101. The functional configuration in this embodiment is an example of a functional configuration realized by, for example, one or more processors executing programs stored in one or more memories. AP101 may be configured to include a wireless communication control unit 401, an information acquisition unit 402, an NPCA control unit 403, an NPCA SP identification unit 404, and an information notification unit 405.

[0030] The wireless communication control unit 401 communicates with other communication devices using the communication unit 306. For example, the wireless communication control unit 401 performs carrier sensing of the PCH and NPCH and communicates using either a first or second communication method based on their respective statuses. For example, when the wireless communication control unit 401 uses TXOP-based NPCA communication, it uses the first communication method when the PCH is idle. Also, when the PCH is busy, the wireless communication control unit 401 determines whether predetermined conditions are met and, based on whether the predetermined conditions are met, communicates using the second communication method. On the other hand, when the wireless communication control unit 401 uses SP-based NPCA communication, it uses the second communication method during the NPCA SP period. Also, outside of the NPCA SP period, the wireless communication control unit 401 may communicate using the first communication method.

[0031] The information acquisition unit 402 acquires TWT information set in OBSS. For example, the information acquisition unit 402 can acquire TWT information set in network 122 from AP102 via DS141. In addition, the information acquisition unit 402 can collect TWT information set in network 123 by receiving frames transmitted in network 123, which is configured by AP103. Furthermore, the information acquisition unit 402 can acquire TWT information set in OBSS from reports from STA110.

[0032] The NPCA control unit 403 determines whether or not to perform communication using NPCA. For example, based on capability information obtained from STA110, the NPCA control unit 403 may decide whether to perform communication using SP-based NPCA, communication using TXOP-based NPCA, or no communication using NPCA at all. The NPCA control unit 403 may also decide to perform both communication using SP-based NPCA and communication using TXOP-based NPCA. Furthermore, if the NPCA control unit 403 decides to perform communication using SP-based NPCA, it determines whether or not to perform communication using NPCA based on the duration length of the TWT SP set in OBSS. For example, if the duration length of the TWT SP is smaller than a predetermined threshold, the NPCA control unit 403 may determine that communication using NPCA should not be performed. Furthermore, if the duration length of the TWT SP is larger than a predetermined threshold, the NPCA control unit 403 may determine that communication using NPCA should be performed. Furthermore, the NPCA control unit 403 may determine to change the PCH if the duration of the TWT SP is greater than another threshold that is greater than a predetermined threshold.

[0033] The NPCA SP Identification Unit 404 identifies the NPCA SP. For example, the NPCA SP Identification Unit 404 may identify the period corresponding to the TWT SP of OBSS as the NPCA SP. The Information Notification Unit 405 notifies the STA110 of information regarding communication using NPCA. For example, the Information Notification Unit 405 may notify the STA110 that communication using SP-based NPCA will be performed. The Information Notification Unit 405 may also notify the STA110 of information for identifying the NPCA SP.

[0034] Figure 5 shows an example of the functional configuration of STA110. The functional configuration in this embodiment is an example of a functional configuration realized by, for example, one or more processors executing programs stored in one or more memories. STA110 may be configured to include a wireless communication control unit 501, an information acquisition unit 502, an NPCA control unit 503, an NPCA SP identification unit 504, and an information notification unit 505.

[0035] The wireless communication control unit 501 may be configured similarly to the wireless communication control unit 401. The information acquisition unit 502 acquires information from AP101 regarding communication used for NPCA. For example, the information acquisition unit 502 may acquire information from AP101 indicating that communication using SP-based NPCA is being performed. The information acquisition unit 502 may also acquire information from AP101 to identify the NPCA SP. Furthermore, the information acquisition unit 502 may acquire TWT information set in OBSS by receiving frames transmitted in OBSS.

[0036] The NPCA control unit 503 performs control for communication using NPCA. For example, the NPCA control unit 503 performs control for communication using TXOP-based NPCA or SP-based NPCA. As an example, when the NPCA control unit 503 obtains information from AP 101 indicating that communication using SP-based NPCA will be performed, it can set an NPCA SP schedule in its own device. For example, the NPCA control unit 503 can set an NPCA SP schedule in its own device based on information for identifying the NPCA SP obtained from AP by the information acquisition unit 502. When the NPCA SP starts, the NPCA control unit 503 controls the wireless communication control unit 501 to switch from communication using the first communication method to communication using the second communication method. Also, when the NPCA SP ends, the NPCA control unit 503 controls the wireless communication control unit 501 to switch from communication using the second communication method to communication using the first communication method.

[0037] The NPCA SP Identification Unit 504 identifies the NPCA SP. For example, if the NPCA SP Identification Unit 504 receives information from AP101 for identifying the NPCA SP, it can identify the NPCA SP based on the received information. Also, if the NPCA SP Identification Unit 504 receives information from AP101 regarding TWT set in OBSS and information necessary to determine whether or not to perform communication using SP-based NPCA, it can identify the NPCA SP using this information. The Information Notification Unit 505 notifies AP101 of information regarding communication using NPCA. For example, the Information Notification Unit 505 can notify AP101 of its own device capability information regarding NPCA. Also, the Information Notification Unit 505 can notify AP101 of information regarding TWT obtained from frames received from OBSS.

[0038] (Process flow) Below, we will describe some examples of the processing flow performed by AP101 and STA110 in this embodiment. First, we will use Figure 6 to explain the overview of communication using SP-based NPCA performed between AP101 and STA110. In addition to an example of a communication sequence performed between AP101 and STA110, Figure 6 also shows an example of a communication sequence performed between AP102 and STA113 and STA114, which constitute OBSS (network 122). As mentioned above, AP101 and AP102 can communicate via DS141. This sequence may be performed after AP101 has established connections with STA111 and STA112. AP101 may obtain capability information indicating whether STA111 and STA112 are capable of performing communication using NPCA when establishing connections with STA111 and STA112, respectively. For example, AP101 may obtain capability information from STA111 and STA112 indicating whether they support SP-based NPCA, TXOP-based NPCA, or both, or neither. Based on the acquired capability information, AP101 may determine the communication method to be used with each STA110 and communicate using the determined method. In this example, AP101 is assumed to have obtained capability information from both STA111 and STA112 indicating support for the SP-based NPCA method. The connection between AP101 and STA110 may be established by exchanging Probe Request frames, Probe Response frames, Association Request frames, Association Response frames, etc. AP101 may obtain capability information indicating whether STA110 is capable of performing communication using NPCA using these frames. AP101 may also notify STA110 of capability information indicating whether its own device is capable of performing communication using NPCA using these frames and Beacon frames.

[0039] AP101 performs NPCA negotiation with STA110 (F601). For example, AP101 may decide with each STA110 to perform communication using SP-based NPCA, communication using TXOP-based NPCA, or no NPCA at all. AP101 may also decide to perform both SP-based NPCA and TXOP-based NPCA communication with STA110. AP101 may perform NPCA negotiation based on capability information obtained from each STA110 if STA110 supports at least one of TXOP-based NPCA or SP-based NPCA. AP101 may also negotiate with STA110 regarding the execution of communication using other types of NPCA. In this embodiment, it is assumed that AP101 has decided to perform communication using SP-based NPCA with STA111 and STA112, respectively. AP101 may determine the SPCH when performing SP-based NPCA communication with STA110.

[0040] AP101 performs a procedure for multi-AP coordination with AP102 (F602). Multi-AP coordination is a function that enables coordinated communication between multiple APs. For example, AP101 can coordinate with AP102 to exchange information about the BSS configured by each device. AP101 can also coordinate with AP102 to communicate data with STA110. For example, AP101 can perform coordinated transmission with AP102 or relay data via AP102. Coordinated transmission includes coordinated transmit power control, beamforming, Joint Transmission, OFDMA, etc., between APs. In this example, AP101 performs a multi-AP coordination procedure to obtain information about the TWT set in the OBSS configured by AP102 from AP102. For example, AP101 sends a message to AP102 that includes information requesting that AP102 notify it of the TWT set in network 122. AP102 sends an acknowledgment of the message received from AP101.

[0041] Subsequently, AP102 may set a TWT with STA113 and STA114. The TWT can be set through negotiation between AP102 and each of STA113 and STA114 using a TWT Setup frame. During the negotiation, the period during which each STA should maintain the AWAKE state (TWT SP) and the start timing of the next TWT SP may be determined. For example, AP102 receives a TWT Request frame from STA113 (F603). The TWT Request frame may contain information specifying the duration of the TWT SP that AP102 and STA113 are requesting to be set, as well as the interval between TWT SPs. Upon receiving the TWT Request frame, AP102 responds using a TWT Response frame (F605). The TWT Response frame may contain information specifying the duration of the TWT SP that AP102 will set with STA113, as well as the interval between TWT SPs. This allows the TWT to be set between AP102 and STA113. STA113 may enter an AWAKE state during the TWT SP period of the configured TWT, and a DOZE state during the interval between TWT SPs. The AWAKE state is a state in which STA113 can communicate with AP102, while the DOZE state may be a state in which STA113 cannot communicate with AP102 due to power-saving operation or other reasons. Furthermore, AP102 may send a TWT Response frame to STA114 without receiving a TWT Request frame from STA114. Such a TWT Response frame sent without receiving a TWT Request frame may be called an Unsolicited TWT Response frame. Through the communication of an Unsolicited TWT Response frame, a TWT may be established between AP102 and STA114. The Unsolicited TWT Response frame may contain information that specifies the duration of the TWT SP and the interval between TWT SPs of the TWT that AP102 sets with STA114.Furthermore, AP102 can use Beacon frames to configure TWTs used by multiple STAs in network 122. Such TWTs used by multiple STAs may be called Broadcast TWTs. In this case, the Beacon frame may include information that specifies the duration and interval of the TWT SPs. Information regarding the timing of the transmission of Beacon frames containing TWT information related to Broadcast TWTs may be exchanged during TWT negotiation between AP102 and STA113 or STA114. It may also be notified in the Broadcast TWT Persistence subfield, which will be described later. AP102 also notifies AP101 of information regarding the TWTs configured in network 122 (F607). For example, AP102 may notify AP101 of information that identifies each configured TWT and BSS, the number of STAs participating in each TWT, the duration for which TWT SPs are configured, and the interval between TWT SPs. Furthermore, when each TWT SP is initiated, AP102 may notify AP101 of information that determines whether or not AP102 will send a Trigger frame.

[0042] AP101 determines whether or not to use SP-based NPCA communication during the TWT SP period of a TWT, based on the TWT information obtained from AP102. For example, AP101 determines that SP-based NPCA communication should not be performed if the duration of the TWT SP is shorter than a predetermined threshold. Conversely, AP101 determines that SP-based NPCA communication should be performed if the duration of the TWT SP is longer than a predetermined threshold. AP101 may also create integrated OBSS TWT Information and determine whether or not to use SP-based NPCA communication based on the integrated OBSS TWT Information. Integrated OBSS TWT Information is a single TWT piece created by AP101 using information from one or more TWTs obtained from other APs, as described later. Integrated OBSS TWT Information may be created under a different name to identify the NPCA SP that performs SP-based NPCA communication. For example, AP101 may determine that SP-based NPCA should be performed based on the fact that the sum of the durations of TWT SPs included in the integrated OBSS TWT information over a certain period exceeds a predetermined threshold. If AP101 determines that communication using SP-based NPCA should be performed, it notifies STA111 and STA112 of the integrated OBSS TWT information or information generated based on the integrated OBSS TWT information. For example, AP101 may notify STA111 and STA112 of information indicating that it will perform communication using SP-based NPCA. AP101 may also notify STA111 and STA112 of information identifying the NPCA SP. When STA111 and STA112 receive the integrated OBSS TWT information or information generated based on the integrated OBSS TWT information from AP101, they prepare to perform communication using SP-based NPCA. For example, STA111 and STA112 set the NPCA SP identified based on the received information in their own devices.

[0043] When NPCA SP occurs, AP101, STA111, and STA112 switch from communication using the first communication method to communication using the second communication method (F610). For example, AP101, STA111, and STA112 switch the carrier sensing channel from PCH to SPCH. AP101 and STA110 may switch before NPCA SP starts, taking into account the switching time required for switching from the first to the second communication method in their own devices. Then, AP101, STA111, and STA112 exchange data using the second communication method (F611, F612). In Figure 6, data transmitted by AP101 to STA111 (F611) and data transmitted by STA112 to AP101 (F612) are shown, but STA111 may also transmit data to AP101, and AP101 may transmit data to STA112. When NPCA SP ends, AP101, STA111, and STA112 switch from communication using the second communication method to communication using the first communication method (F617). For example, AP101, STA111, and STA112 switch the carrier sensing channel from SPCH to PCH. AP101 and STA110 may switch before NPCA SP ends, taking into account the switching time required for switching from the second communication method to the first communication method in their own devices. Then, AP101, STA111, and STA112 exchange data using communication with the first communication method (F618). Meanwhile, in network 122 configured by AP102, communication using the first communication method may occur in the TWT SP of the configured TWT. For example, data may be exchanged between AP102 and STA113 and STA114 in the TWT SP (F613~F616). Furthermore, the duration of the TWT SP in the TWT set in network 122 and the NPCA SP in network 121 may be the same, or there may be a difference. For example, the duration of the NPCA SP may start earlier and end later than the duration of the TWT SP. This ensures that the data exchanged in the TWT SP in OBSS is protected.Furthermore, the NPCA SP period may start and end earlier than the TWT SP period. This allows for a switching time to occur when switching from communication using the second communication method to communication using the first communication method, and enables communication using the first communication method to start in network 121 at the same time as the OBSS TWT SP ends. Note that Figure 6 shows a situation where one TWT is set in network 122, but a TWT may have a TWT SP set periodically within a single TWT. Also, multiple TWTs may be set in a single network. For example, different individual TWTs may be set between AP102 and STA113 and STA114, respectively. In addition, AP102 may set one or more Broadcast TWTs in addition to the individual TWTs set between STA113 and STA114.

[0044] (TWT information acquisition process in OBSS) This section describes examples of how AP102 operates when setting up a TWT on network 122, and how AP101 operates when obtaining information about the TWT set up on network 122 from AP102. The operation of AP102 setting up a TWT on network 122 corresponds to F603 to F606 in Figure 6. The operation of AP101 obtaining information about the TWT set up on network 122 from AP102 corresponds to F607 in Figure 6. AP102 can set up a TWT using a frame that includes a TWT element. A TWT element is one of the Information Elements (information elements) communicated between the AP and STA. For example, a TWT element may be included in a TWT Request frame (F603), a TWT Response frame (F604, F605), a Beacon frame (F606), etc. in Figure 6. A TWT Request frame may be a TWT Setup frame with the value of the TWT Request field set to 1. Furthermore, a TWT Response frame may be a TWT Setup frame with the value of the TWT Request field set to 0. A TWT Setup frame may be one of the Action frames. TWT elements may be included in frames other than TWT Setup frames. For example, a TWT element may be included in a frame used when establishing a connection between the AP and STA. Frames used when establishing a connection between the AP and STA include, for example, a Probe Request frame, a Probe Response frame, an Association Request frame, and an Association Response frame. In this case, AP102 may set up a TWT with STA113 or STA114 along with establishing the connection.

[0045] Figure 7 shows an example of the configuration of a TWT element. A TWT element may consist of an Element ID field 701, a Length field 702, a Control field 703, and a TWT Parameter Information field 704. The Element ID field 701 indicates the type of information element. For example, if the value of the Element ID field 701 is 216, it indicates that this information element is a TWT element. The Length subfield 702 indicates the length of the information element. The Control field 703 consists of the subfields shown in Figures 8(A) and 8(B). The TWT Parameter Information field 704 may consist of the Individual TWT Parameter Information Set field shown in Figure 9. Alternatively, the TWT Parameter Information field 704 may consist of the Broadcast TWT Parameter Information Set field shown in Figure 10.

[0046] Figure 8(A) shows an example configuration of the Control field 703. The Control field 703 may include the NDP Paging Indicator subfield 801, the Responder PM Mode subfield 802, and the Negotiation Type subfield 803. The Control field 703 may also include the TWT Information Frame Disabled subfield 804, the Wake Duration Unit subfield 805, and the Reserved subfield 806. The NDP Paging Indicator subfield 801 indicates the presence or absence of the NDP Paging subfield, which will be described later. The Responder PM Mode subfield 802 indicates the power saving management mode of the responding communication device. The Negotiation Type subfield 803 may indicate whether the information contained in the TWT element is for the negotiation of Broadcast TWT parameters or for the negotiation of individual TWT parameters. The Negotiation Type subfield 803 may also indicate whether the information contained in the TWT element is for the negotiation of parameters for the Wake TBTT interval. The MSB (Most Significant Bit) of the Negotiation Type subfield 803 can be called the Broadcast field. The information shown in the Target Wake Time field 902, described later, differs depending on the value of the Negotiation Type subfield 804. The information shown in the TWT Wake Interval Mantissa field 905 and the TWT Wake Interval Exponent field 917, described later, also differs depending on the value of the Negotiation Type subfield 804. Figure 8(B) shows an example of the information shown in the Target Wake Time field 902 according to the value of the Negotiation Type subfield 803.Figure 8(B) also includes an example of the information shown by the TWT Wake Interval Mantissa field 905 and the TWT Wake Interval Exponent field 917. Here, the values ​​of the Target Wake Time field 902 and the TWT Wake Interval Mantissa field 905 being 0 may indicate that the TWT SP is not periodic. That is, the value of at least one of the Target Wake Time field 902 or the TWT Wake Interval Mantissa field 905 being non-zero may indicate that the TWT SP is periodic.

[0047] The TWT Information Frame Disabled subfield 804 is set to a value of 1 when the TWT Information frame cannot be received. The Wake Duration Unit subfield 805 indicates the unit of information shown by the Nominal Minimum TWT Wake Duration subfield 904, which will be described later. For example, if the value of the Wake Duration Unit subfield 805 is 0, the unit is 256 μs, and if the value of the Wake Duration Unit subfield 805 is 1, the unit is 1 TU. 1 TU (Time Unit) is 1024 μs. The Reserved subfield 806 is a reserved area.

[0048] The TWT Parameter Information field 704 contains one Individual TWT Parameter Set field if the value of the Broadcast field in the Control field 703 is 0. On the other hand, the TWT Parameter Information field 704 contains one or more Broadcast TWT Parameter Set fields if the value of the Broadcast field in the Control field 703 is 1. Figure 9 shows an example of the configuration of an Individual TWT Parameter Set field. The Individual TWT Parameter Set field contains the Request Type subfield 901, the Target Wake Time subfield 902, and the TWT Group Assignment subfield 903. The Individual TWT Parameter Set field contains the Nominal Minimum TWT Wake Duration subfield 904 and the TWT Wake Interval Mantissa subfield 905. The Individual TWT Parameter Set field contains the TWT Channel subfield 906 and the NDP Paging subfield 907. The Request Type subfield 901 includes the TWT Request subfield 911, the TWT Setup Command subfield 912, the Trigger subfield 913, and the Implicit subfield 914. The Request Type subfield 901 also includes the Flow Type subfield 915 and the TWT Flow Identifier subfield 916. The Request Type subfield 901 also includes the TWT Wake Interval Exponent subfield 917 and the TWT Protection subfield 918.

[0049] The TWT Request subfield 911 can be set to a value of 1 to indicate that the communication device 100 transmitting the TWT element is the TWT requesting STA. For example, if the STA requests the configuration of a TWT, the TWT Request subfield 911 will be set to a value of 1. The TWT Request subfield 911 can also be set to a value of 0 to indicate that the communication device 100 transmitting the TWT element is the TWT responding STA. For example, if the AP responds to the TWT configuration requested by the STA, the TWT Request subfield 911 will be set to a value of 0. In the case of a Broadcast TWT, the TWT Request subfield 911 will be set to a value of 1 if the communication device 100 transmitting the TWT element is the TWT scheduled STA. The TWT Request subfield 911 will be set to a value of 0 if the communication device 100 transmitting the TWT element is the TWT scheduling STA.

[0050] The TWT Setup Command subfield 912 indicates the type of TWT command. For example, if the TWT Setup Command subfield 912 is set to a value of 0 by the requesting STA of the TWT, it indicates that the TWT command is Request TWT. For example, Request TWT indicates joining the TWT without specifying a Target Wake Time. If the TWT Setup Command subfield 912 is set to a value of 1 by the requesting STA of the TWT, it indicates that the TWT command is Suggest TWT. For example, Suggest TWT indicates joining the TWT by specifying an applicable value from the proposed TWT parameters. Note that the TWT parameters include the values ​​set in the Nominal Minimum TWT Wake Duration subfield 904, the TWT Channel subfield 906, and the Trigger subfield 913, respectively. Also, the TWT parameters include the values ​​set in the TWT Wake Interval Mantissa subfield 905 and the TWT Wake Interval Exponent subfield 917, respectively. The TWT Setup Command subfield 912, when set to a value of 2 by the requesting STA of the TWT, indicates that the TWT command is TWT Demand. For example, TWT Demand indicates joining a TWT by specifying the requested TWT parameters. The TWT Setup Command subfield 912, when set to a value of 3 by the responding STA of the TWT, indicates that the TWT command is TWT Grouping. For example, TWT Grouping indicates proposing TWT group parameters different from those specified or requested by the requesting STA of the TWT. The TWT Setup Command subfield 912, when set to a value of 4 by the responding STA of the TWT, indicates that the TWT command is Accept TWT. For example, Accept TWT indicates accepting a TWT with the TWT parameters specified by the other party's STA.The TWT Setup Command subfield 912, when set to a value of 5 by the responding STA of the TWT, indicates that the TWT command is an Alternate TWT. For example, an Alternate TWT suggests alternative TWT parameters to those specified by the other party's STA. The TWT Setup Command subfield 912, when set to a value of 6 by the responding STA of the TWT, indicates that the TWT command is a Dictate TWT. For example, a Dictate TWT suggests alternative TWT parameters to those specified by the other party's STA. The TWT Setup Command subfield 912, when set to a value of 7 by the responding STA of the TWT, indicates that the TWT command is a Reject TWT. For example, a Reject TWT indicates rejection of the TWT Setup. A Reject TWT may also indicate termination of an existing broadcast TWT or termination of membership in a broadcast TWT. In the case of a Broadcast TWT, the requesting STA of the TWT mentioned above may be the STA on the side where the TWT is scheduled, and the responding STA of the TWT may be the STA on the side where the TWT is scheduled.

[0051] The Trigger subfield 913 indicates that a frame containing a Trigger frame or TRS is sent within the TWT SP. TRS stands for Triggered Response Scheduling. A TWT in which a frame containing a Trigger frame or TRS is sent within the TWT SP may be called a trigger-enabled TWT. The Implicit subfield 914 indicates that an Implicit TWT is executed when set to a value of 1, and an Explicit TWT is executed when set to a value of 0. In this example, the value of the Implicit subfield 914 may be set to 1, and the value of the NDP Paging Indicator subfield 801 may be set to 0. The Flow Type subfield 915 and TWT Flow Identifier subfield 916 provide information about the operation when power saving mode is executed. The TWT Wake Interval Exponent subfield 917, along with the TWT Wake Interval Mantissa subfield 905, indicates the TWT Wake Interval, as shown in Figure 8(B). The TWT Wake Interval is the interval between TWT SPs. The TWT wake interval can be expressed as an exponent with a base of 2, the mantissa being the value of the TWT Wake Interval Mantissa field 905, and the exponent being the value of the TWT Wake Interval Exponent subfield 917. The unit of the TWT wake interval is μs. The TWT Protection subfield 918 is used by the requesting STA of the TWT to request frame protection by NAV.

[0052] The Target Wake Time subfield 902, as described above in Figure 8(B), displays different information depending on the value of the Negotiation Type subfield 803. For example, if the value of the Negotiation Type subfield 803 is 0, the Target Wake Time subfield 902 indicates the start time of a future Individual TWT SP. The value shown in the Target Wake Time subfield 902 can be expressed using the Timing Synchronization Function (TSF) of the IEEE 802.11 standard. The TWT Group Assignment subfield 903 indicates the TWT group assigned to the STA requesting the TWT. The Nominal Minimum TWT Wake Duration subfield 904 indicates the minimum time that the STA requesting the TWT will maintain the AWAKE state. For example, the value shown in the Nominal Minimum TWT Wake Duration subfield 904 can be used as the TWT SP. The TWT Wake Interval Mantissa subfield 905, as described above, along with the TWT Wake Interval Exponent subfield 917, indicates the TWT Wake Interval. TWT Channel 906 indicates the channel that the STA requesting the TWT requests to be used temporarily as the primary channel during the TWT SP. The NDP Paging subfield 907 is an optional area.

[0053] Figure 10 shows an example of the configuration of a Broadcast TWT Parameter Set field. The Broadcast TWT Parameter Set field includes the Request Type subfield 1001 and the Target Wake Time subfield 902. The Broadcast TWT Parameter Set field also includes the Nominal Minimum TWT Wake Duration subfield 904. The Broadcast TWT Parameter Set field also includes the TWT Wake Interval Mantissa subfield 905 and the Broadcast TWT Info subfield 1002. Note that for configurations identical to those in Figure 9, the same reference number is used and the explanation is omitted. For example, the Broadcast TWT Parameter Set field differs from the Individual TWT Parameter Set field in that it has the Broadcast TWT Info subfield 1002. The Request Type subfield 1001 includes the Last Broadcast Parameter Set subfield 1003 and the Broadcast TWT Recommendation subfield 1004. For subfields included in Request Type subfield 1001 that are also included in Request Type subfield 911, the same reference number is assigned, and their descriptions are omitted.

[0054] The Last Broadcast Parameter Set subfield 1003 shows a value of 0 if there are subsequent Broadcast TWT Parameter Set fields. That is, it shows a value of 1 if this Broadcast TWT Parameter Set field is the last Broadcast TWT Parameter Set field in the TWT element. The Broadcast TWT Recommendation subfield 1004 shows information about the frames sent within the TWT SP. When the Broadcast TWT Recommendation subfield 1004 is set to a value of 0, it indicates that there are no restrictions on the frames sent within the TWT SP. When the Broadcast TWT Recommendation subfield 1004 is set to a value of 1, PS-Poll, QoS Null, QoS Control, and HE TB feedback NDP feedback are recommended. Also, when the Broadcast TWT Recommendation subfield 1004 is set to a value of 1, frames that are part of BQR, BSR, and sounding feedback exchange are recommended. BQR is an abbreviation for Bandwidth Query Report. BSR is an abbreviation for Buffer Status Report. If the Broadcast TWT Recommendation subfield 1004 is set to 1, the Action frame or Action No Ack frame from the Management frame is recommended. If the Broadcast TWT Recommendation subfield 1004 is set to 1, the Control response frame and the Trigger frame for random access are recommended. If the Broadcast TWT Recommendation subfield 1004 is set to 2, in addition to the above frames, the (Re)Association Request frame is recommended.A value of 3 in the Broadcast TWT Recommendation subfield 1004 indicates that there are no restrictions on the frames to be transmitted, except for TIM and FILS frames. TIM stands for Traffic Indication Map. FILS stands for Fast Initial Link Setup. Values ​​of 4 to 7 in the Broadcast TWT Recommendation subfield 1004 indicate Reserved.

[0055] Broadcast TWT Info 1002 includes a Reserved subfield 1006, a Broadcast TWT ID subfield 1007, and a Broadcast TWT Persistence subfield 1008. The Broadcast TWT ID subfield 1007 is used to identify the Broadcast TWT. For example, the Broadcast TWT ID can be used in combination with the AP's MAC address to uniquely identify the TWT. The Broadcast TWT Persistence subfield 1008 indicates the number of TBTTs until the Broadcast TWT schedule corresponding to this Broadcast TWT parameter set exists. TBTT is an abbreviation for Target Beacon Transmission Time. Note that in the IEEE 802.11be standard, Broadcast TWT frames are used in R-TWTs used for low-latency traffic communication.

[0056] AP102 uses the frame containing the aforementioned TWT element to determine the TWT parameters to be set between STA113 and STA114. For example, AP102 can determine the TWT parameters of individual TWTs between STA113 and STA114 using a TWT element containing the Individual TWT Parameter Set field. As an example, AP102 can use the Nominal Minimum TWT Wake Duration subfield 904 to determine the duration of a TWT SP with STA113 and STA114. AP102 can use the TWT Wake Interval Exponent subfield 917 and the TWT Wake Interval Mantissa subfield 905 to determine the interval between TWT SPs with STA113 and STA114. AP102 can use the Trigger subfield 913 to determine with STA113 and STA114 whether or not to send a frame containing a Trigger frame or TRS within a TWT SP. Furthermore, AP102 can set a TWT SP to be used for one or more STAs included in the BSS using a TWT element that includes a Broadcast TWT Parameter Set field. In this case, AP102 can notify the TWT parameters to be used for the Broadcast TWT using a Beacon frame that includes a Broadcast TWT Parameter Set field. Note that the information elements that AP102 uses to set the TWT are not limited to TWT elements. For example, AP102 can set the TWT by determining the duration of the TWT SP, the interval between TWT SPs, etc., with the STA connected to its BSS using information elements other than TWT elements.

[0057] When AP102 sets a TWT, it notifies AP101 of information about the set TWT. For example, AP102 may notify AP101 of information such as the identification information of each set TWT, the number of STAs participating in each TWT, the period for which TWT SPs are set, and the interval between TWT SPs. For example, if AP102 sets individual TWTs with STA113 and STA114, it may notify AP101 of the information contained in the TWT elements used to determine the parameters with each STA. Also, if AP102 sets a Broadcast TWT, it may notify AP101 of the information contained in the TWT elements of the Beacon frame. When AP102 notifies AP101 of information about the set TWT, it may use frames defined in the IEEE 802.11 standard series. For example, if a connection is established between AP101 and AP102 using the multi-AP cooperation procedure shown in F602 of Figure 6, information can be exchanged using frames for inter-AP communication as defined in the IEEE 802.11 standard. In this case, AP102 may send to AP101 a frame for inter-AP communication that includes TWT elements containing the configured TWT parameters. For example, AP102 may send to AP101 a frame that includes the Target Wake Time subfield 902, the Nominal Minimum TWT Wake Duration subfield 904, etc. AP102 may also send to AP101 a frame that includes the TWT Wake Interval Exponent subfield 917 and the TWT Wake Interval Mantissa subfield 905.

[0058] (Decision process for executing SP-based NPCA) This section describes the process by which AP101 determines whether or not to perform an SP-based NPCA. This process corresponds to F608 in Figure 6. When AP101 obtains information about a TWT from another AP (e.g., AP102), it determines whether or not to perform an SP-based NPCA based on the obtained information. For example, if AP101 obtains information about one TWT from AP102, it may determine whether or not to perform an SP-based NPCA based on this information. As an example, if AP101 obtains information about one Broadcast TWT set by AP102, it may make a determination by comparing the duration of the TWT SP of that Broadcast TWT with a predetermined threshold. Figures 11(A) to 11(C) show examples of the operation when making a determination by comparing the duration of the TWT SP with a predetermined threshold. In each of Figures 11(A) to 11(C), the horizontal axis shows the passage of time. For example, in each TWT SP start time 1101 shown in Figure 11(A), TWT SP 1103 starts. TWT SP1103 lasts for the duration of TWT SP. TWT SP1103 is periodically set based on the interval between TWT SP1103, indicated by Interval1102. For example, TWT SP start time1101 may correspond to the value indicated by the Target Wake Time subfield 902. Interval1102 may correspond to the values ​​indicated by the TWT Wake Interval Exponent subfield 917 and the TWT Wake Interval Mantissa subfield 905. The duration of TWT SP1103 may correspond to the value indicated by the Nominal Minimum TWT Wake Duration subfield 904. Note that in Figures 11(A) to (C), Interval1102 shows the time interval between TWT SP start times1101, but a different time interval may be shown. For example, Interval1102 may be the time interval from the end time of one TWT SP1103 to the start time of the next TWT SP1103.In this case, the values ​​of the TWT Wake Interval Exponent subfield 917 and the TWT Wake Interval Mantissa subfield 905 may also be set in this way. Figures 11(A) to (C) show TWT SPs 1103, 1106, and 1107 with different durations. The first threshold 1104 and the second threshold 1105, shown in each of Figures 11(A) to (C), which are used to determine whether or not to perform an SP-based NPCA, are compared with the durations of TWT SPs 1103, 1106, and 1107. The first threshold 1104 and the second threshold 1105 are shown as periods of predetermined length with TWT SP start time 1101 as the start time. Here, the first threshold < the second threshold. The first and second thresholds may be predetermined set values.

[0059] In Figure 11(A), the duration of TWT SP1102 is less than both the first threshold 1104 and the second threshold 1105. In this case, AP101 may determine that it should not perform SP-based NPCA. When AP101 or STA110 switches from the first communication method to the second communication method, a switching time may occur. If TWT SP is short, there is a high possibility that communication using NPCA cannot be performed even after switching, so AP101 may determine not to perform SP-based NPCA in the case of Figure 11(A). In Figure 11(B), the duration of TWT SP 1106 is greater than the first threshold and less than the second threshold. In this case, AP101 may determine that it should perform SP-based NPCA. In Figure 11(C), the duration of TWT SP1107 is greater than both the first threshold and the second threshold. In this case, AP101 may determine that the PCH should be changed to another channel. If the duration of the TWT SP set in OBSS is long, a large amount of traffic is transmitted on that TWT SP, and the PCH may become congested even outside the TWT SP period. Therefore, if that PCH continues to be used, the overall throughput of network 121 is likely to decrease. For this reason, AP101 may determine that the PCH should be changed in the case of Figure 11(C). If the PCH is changed, AP101 notifies its BSS with information that allows it to identify the changed PCH. AP101 and STA110 then use the changed PCH to perform communication using the first communication method or communication using the second communication method.

[0060] The first and second thresholds can be set based on factors such as the switching time between the first and second communication methods and the tolerance for PCH changes in AP101 and STA110. The switching time for AP101 and STA110 to switch from the first to the second communication method may be a value indicated as, for example, EMLSR Transition delay. EMLSR Transition delay can be notified from STA110 to AP101 via the EMLSR Parameter update field of the EMLSR Operating Mode Notification frame. Here, EMLSR stands for Enhanced Multi-Link Single-Radio. For example, AP101 can set the first threshold 1104 by using the EMLSR Transition delay obtained from STA110 as the switching time for STA110 to switch from the first to the second communication method. Furthermore, AP101 can use values ​​specified by the IEEE 802.11 standard series, Wi-Fi standards, and national regulations as the first threshold 1104 and the second threshold 1105.

[0061] AP101 may use the sum of the durations of TWT SPs within a given period as the duration of TWT SPs. For example, even if the duration of one TWT SP is less than the second threshold, if the interval between TWT SPs is short, the PCH is more likely to become congested. Therefore, AP101 may determine that the PCH should be changed if the sum of the durations of TWT SPs within a given period is greater than the second threshold. Similarly, AP101 may determine that SP-based NPCA should not be performed if the sum of the durations of TWT SPs within a given period is less than the first threshold. Furthermore, AP101 may determine that SP-based NPCA should be performed if the sum of the durations of TWT SPs within a given period is greater than the first threshold and less than the second threshold.

[0062] AP101 can obtain information on multiple TWT SPs from other APs. For example, AP101 can obtain information on individual TWTs set by AP102 between STA113 and STA114, respectively. In addition, AP101 can obtain information on Broadcast TWTs set by AP102. AP101 can combine this information on multiple TWTs to generate information on a single TWT. Information on a single TWT generated based on the TWT information of one or more OBSSs will be called integrated OBSS TWT information. Integrated OBSS TWT information may include information such as the start timing of the TWT SP, the duration of the TWT SP, and the interval between TWT SPs. The method for generating integrated OBSS TWT information will be explained using Figure 12. Figure 12 shows the TWT SP start time 1211, Interval 1212, and TWT SP 1213 of the first TWT in the upper panel. Figure 12 also shows the TWT SP start time 1221, Interval 1222, and TWT SP 1223 of the second TWT in the middle section. The bottom section of Figure 12 shows the TWT SP start time, Interval, and TWT SP of the integrated TWT based on the integrated OBSS TWT information obtained by integrating the information of the first TWT and the second TWT. For example, the TWT SP in the integrated TWT can be represented as the set of TWT SP 1213 of the first TWT and TWT SP 1223 of the second TWT. AP101 can determine whether or not to perform an SP-based NPCA based on the integrated OBSS TWT information. For example, AP101 can determine that an SP-based NPCA should not be performed if the maximum duration of TWT SP 1213 and TWT SP 1223 included in the integrated TWT is smaller than the first threshold. Furthermore, AP101 may determine that the PCH should be changed if the sum of the durations of TWT SP1213 and TWT SP1223 included in the integrated TWT over a certain duration is greater than a second threshold. In all other cases, AP101 may determine that an SP-based NPCA should be performed. AP101 may perform any other actions not described above.For example, AP101 may determine that an SP-based NPCA should be performed if the average duration of TWT SP1213 and TWT SP1223 included in the integrated TWT is greater than the first threshold but less than the second threshold. In this case, AP101 may determine that an SP-based NPCA should not be performed if the average duration is less than the first threshold.

[0063] AP101 may generate integrated OBSS TWT information based on some of the TWT information obtained from AP102. For example, AP101 can generate integrated OBSS TWT information using information on TWTs that satisfy predetermined conditions. As an example, AP101 can generate integrated OBSS TWT information using information on TWTs whose TWT SPs are periodic, and not using information on TWTs whose TWT SPs are not periodic. By using only TWTs whose TWT SPs are periodic, the process of generating integrated OBSS TWT information can be simplified. Also, AP101 can generate integrated OBSS TWT information using information on TWTs where the number of participating STAs is greater than or equal to a predetermined number, and not using information on TWTs where the number of participating STAs is less than a predetermined number. When the number of participating STAs is small, there is a high possibility that the traffic in the TWT SP of that TWT is small, so even if a TWT is set in OBSS, it may be more efficient to communicate using the first communication method. The number of participating STAs in a TWT may be an absolute number, or it may be a ratio of the number of participating STAs in a TWT to the number of STAs in BSS. The ratio of the number of STAs participating in a TWT to the number of STAs in the BSS may be the value shown in the Station Count subfield of the BSS Load element in the Beacon frame transmitted by AP102. AP101 may also determine whether to use a configured TWT for generating integrated OBSS TWT information based on the fact that it is a Broadcast TWT. For example, AP101 may determine that a Broadcast TWT has more participating STAs than an individual TWT. The conditions for AP101 to select a TWT to use for generating integrated OBSS TWT information are not limited to these. For example, AP101 may use information from a TWT SP whose duration length is greater than a first threshold. This allows for the exclusion of durations that are too short as NPCA SPs from the integrated TWT. Based on the integrated OBSS TWT information generated in this way, based on some of the TWT information obtained from other APs, AP101 may determine whether or not to perform an SP-based NPCA.Furthermore, AP101 can pre-notify other APs (e.g., AP102) of the conditions for selecting the TWT information to be used to generate integrated OBSS TWT information. This allows AP102 to notify AP101 of the TWT information when it sets a TWT that meets the conditions. This can reduce the amount of information that AP102 notifies AP101 of.

[0064] Furthermore, AP101 may combine some of the TWT SPs included in the integrated TWT. Figure 13 shows another example of how integrated OBSS TWT information is generated. In Figure 13, the lower integrated TWT shows the extended TWT SP1331 generated by combining TWT SP1313 of the first TWT and TWT SP1323 of the second TWT. That is, the extended TWT SP1331 covers the period between the first TWT SP1313 of the first TWT, the second TWT SP1323 of the second TWT, and the period between the first TWT SP1313 and the second TWT SP1323. AP101 may generate an extended TWT SP that includes the first TWT SP1313, the second TWT SP1323, and the period between them if the period between the first TWT SP1313 and the second TWT SP1323 included in the integrated TWT is less than a third threshold. The extended TWT SP is treated in the integrated TWT in the same way as a single TWT SP and can be used to determine whether or not to perform communication using SP-based NPCA. This makes it possible to perform communication using NPCA even if the period length of one or both TWT SPs is shorter than the first threshold, based on the fact that the period length of the extended TWT SP is longer than the first threshold.

[0065] In the above explanation, we used an example of generating one integrated OBSS TWT information based on information from two TWTs, but AP101 can generate integrated OBSS TWT information based on information from one or more TWTs. For example, if AP101 obtains information from one TWT from AP102, it can use this TWT information as is for the integrated TWT. Also, if AP101 has information from three or more TWTs obtained from other APs, it can generate integrated OBSS TWT information as a set of TWT SPs contained in these TWTs. Furthermore, before generating integrated OBSS TWT information, AP101 can determine whether each TWT satisfies the conditions for selecting the TWT to be used to generate the integrated TWT information described above, and generate the integrated TWT information using only the information from TWTs that satisfy the conditions.

[0066] (Notification of execution of SP-based NPCA) This section describes the operation of AP101 when it notifies STA110 to initiate communication using SP-based NPCA. This operation corresponds to F609 in Figure 6. When AP101 determines that it should perform communication using SP-based NPCA, it notifies STA110 connected to its device that it will initiate communication using SP-based NPCA. For example, AP101 may notify STA110 connected to its device that it will initiate communication using SP-based NPCA after performing NPCA negotiation and deciding to perform communication using SP-based NPCA. Alternatively, AP101 may notify the entire BSS that it will perform communication using SP-based NPCA. In this case, AP101 may use a Beacon frame to make the notification.

[0067] Furthermore, AP101 may notify STA110 or its own BSS of the period during which communication using SP-based NPCA is performed (NPCA SP). For example, AP101 may determine the NPCA SP based on the generated integrated OBSS TWT information and notify STA110 or its own BSS of the determined NPCA SP. As an example, AP101 may determine the period corresponding to each TWT SP included in the integrated TWT as the NPCA SP. If the integrated TWT includes TWT SPs shorter than a first threshold, AP101 may exclude those TWT SPs when determining the NPCA SP. Also, if the integrated TWT includes TWT SPs where the interval between TWT SPs is shorter than a third threshold, AP101 may determine an NPCA SP that includes the period corresponding to the extended TWT SP formed by combining those TWT SPs.

[0068] AP101 can notify STA110 or its own BSS of the determined NPCA SP using a frame for notifying information about NPCA. The frame for notifying information about NPCA may be a frame defined in the IEEE 802.11 standard series. For example, AP101 may include an information element in the frame for notifying information about NPCA that contains information to identify the determined NPCA SP. This information element may include subfields contained in the TWT element. For example, this information element may include the Target Wake Time subfield 902, the Nominal Minimum TWT Wake Duration subfield 904, etc. Also, this information element may include the TWT Wake Interval Exponent subfield 917, the TWT Wake Interval Mantissa subfield 905. AP101 may include an information element indicating TWT information contained in a frame received from another AP as an information element indicating the NPCA SP in the frame for notifying information about NPCA. For example, AP101 may include at least some of the TWT elements, including information about individual TWTs and Broadcast TWTs obtained from AP102, directly into a frame for notifying information about NPCA. In this case, AP101 may include the information contained in the TWT elements corresponding to the information of one or more TWTs used to generate the integrated OBSS TWT information into a single frame for notifying information about NPCA, as information for identifying the NPCA SP.

[0069] AP101 may pre-determine an NPCA SP with STA110 during NPCA negotiation. In this case, AP101 can adjust the pre-determined NPCA SP based on TWT information obtained from other APs. For example, AP101 may notify STA110 of the difference between the pre-determined NPCA SP and the NPCA SP determined based on TWT information obtained from another AP102 as an offset value. For example, AP101 may notify STA110 of information indicating the pre-determined NPCA SP in the frame used in NPCA negotiation. AP101 may also notify STA110 of the offset value resulting from the difference with the TWT SP obtained from AP102 using a frame for notifying information about NPCA. STA110 can identify the NPCA SP by using the offset value notified by AP101 for the pre-determined NPCA SP.

[0070] Furthermore, AP101 may configure both AP101 and STA110 to determine whether or not to perform communication using SP-based NPCA. In this case, AP101 may notify STA110 of TWT information obtained from other APs and information necessary for STA110 to determine whether or not to perform communication using SP-based NPCA. The information necessary for STA110 to determine whether or not to perform communication using SP-based NPCA may be the first to third thresholds described above. The TWT information obtained from other APs may include information such as the TWT SP start time, TWT Wake Interval, duration of the TWT SP, and whether or not a Trigger frame is included in the TWT SP. If AP101 obtains information for two or more TWTs, it may notify STA110 of the information for each TWT, and may also notify STA110 of integrated OBSS TWT information generated based on this TWT information. When AP101 and STA110 each determine whether or not to use SP-based NPCA communication, they each set an NPCA SP based on their own determination result. Furthermore, AP101 and STA110 each perform a switch from the first communication method to the second communication method at the set NPCA SP. AP101 may use the frame for notifying NPCA information described above to notify TWT information obtained from AP102 and information necessary for STA110 to determine whether or not to use SP-based NPCA communication. Alternatively, AP101 may notify STA110 of the information necessary for STA110 to determine whether or not to use SP-based NPCA communication using a frame used for NPCA negotiation. In this case, AP101 may notify TWT information obtained from other APs using the frame for notifying NPCA information.

[0071] (Execution behavior of SP-based NPCA) This section describes the respective processes when AP101 and STA110 perform communication using SP-based NPCA. This operation corresponds to F610 to F618 in Figure 6. Figure 14 shows an example of the processing flow performed by AP101. This processing flow may be performed based on AP101 establishing a connection with STA110. AP101 performs NPCA negotiation with STA110 (S1401). For example, AP101 may decide whether to perform communication using SP-based NPCA, communication using TXOP-based NPCA, or no NPCA communication at all with STA110. AP101 may also decide to perform both SP-based NPCA and TXOP-based NPCA communication.

[0072] If, through NPCA negotiation, it is decided to perform communication using SP-based NPCA (YES in S1402), AP101 collects OBSS TWT information (S1403). For example, AP101 may perform a procedure to perform multi-AP coordination with AP102 and obtain TWT information set in network 122 from AP102. Alternatively, AP101 may collect OBSS TWT information from frames received from OBSS, as described later (S1404). Based on the collected OBSS TWT information, AP101 determines whether or not to perform communication using SP-based NPCA. For example, AP101 generates integrated OBSS TWT information (S1405). AP101 may generate integrated OBSS TWT information based on TWT information obtained from AP102 and TWT information collected from frames received from OBSS. Then, AP101 determines whether or not to perform communication using SP-based NPCA based on the generated integrated OBSS TWT information (S1406). For example, AP101 may determine whether or not to perform communication using SP-based NPCA by comparing the duration of the TWT SP included in the integrated OBSS TWT information with the first to third thresholds. As an example, if the duration of the TWT SP is less than the first threshold, AP101 determines that communication using SP-based NPCA should not be performed. If the duration of the TWT SP is greater than the second threshold, AP101 determines that the PCH should be changed. If the duration of the TWT SP is greater than the first threshold and less than the second threshold, AP101 determines that communication using SP-based NPCA should be performed. Furthermore, if the interval between TWT SPs is smaller than the third threshold, AP101 may combine those TWT SPs to generate an extended TWT SP and perform a determination on that extended TWT SP using the first and second thresholds. If AP101 determines that communication using SP-based NPCA should be performed (YES in S1406), it will initiate communication using NPCA and send information to STA110 to identify the NPCA SP (S1407).For example, AP101 may notify STA110 of the generated integrated OBSS TWT information as information to identify the NPCA SP. When it is time for the NPCA SP, AP101 switches from the first communication method to the second communication method and performs communication using NPCA (S1408).

[0073] If AP101 determines that communication using SP-based NPCA should not be performed (NO in S1406), it may change the TWT information used to generate integrated OBSS TWT information and perform the determination again whether or not to perform communication using SP-based NPCA. For example, AP101 may increase the threshold for the number of STAs participating in the TWT in the condition for selecting the TWT information used to generate integrated OBSS TWT information. If the threshold for the number of STAs participating in the TWT is increased, some TWTs may be excluded from the TWTs used to generate integrated OBSS TWT information. AP101 performs the determination again using the integrated OBSS TWT information generated by changing the TWT information used to generate integrated OBSS TWT information (S1405) and the first to third thresholds (S1406). Alternatively, if AP101 does not change the TWT information used to generate integrated OBSS TWT information (NO in S1411), it determines that communication using NPCA should not be performed (S1412). In this case, AP101 maintains communication using the first communication method. Furthermore, if AP101 determines that communication using NPCA should not be performed, it may notify STA110 that it will not perform communication using NPCA.

[0074] On the other hand, if the NPCA negotiation determines that TXOP-based NPCA will be performed (NO in S1402 and YES in S1409), AP101 will perform communication using TXOP-based NPCA (S1410). For example, AP101 monitors the state of the PCH. When AP101 detects a signal on the PCH, it determines whether the detected signal was transmitted on its own BSS or on the OBSS. If the signal was transmitted on its own BSS, AP101 performs reception processing for that signal. On the other hand, if the signal was transmitted on the OBSS, AP101 sets NAV on the PCH and switches the channel being monitored from the PCH to the SPCH. For example, if AP101 is performing carrier sense to transmit data, it determines whether the SPCH is available and performs communication using NPCA. Also, if the communication device 100 is monitoring to receive data, it performs reception processing when it receives a signal on the SPCH. When the NAV set on the PCH expires, AP101 switches the monitoring channel from SPCH to PCH.

[0075] If AP101 decides not to perform NPCA communication during NPCA negotiation with STA110 (NO in S1402 and NO in S1409), it will not perform NPCA communication and will maintain communication using the first communication method (S1412).

[0076] Next, the operation of AP101 when performing SP-based NPCA communication (S1408) will be explained using Figure 15. When NPCA SP is started (YES in S1501), AP101 switches from communication using the first communication method to communication using the second communication method. AP101 may decide whether to postpone switching to the second communication method until a trigger frame is detected in OBSS before switching to the second communication method. For example, AP101 may decide to detect a trigger frame if the TWT information obtained from another AP indicates that it is a trigger-enabled TWT. In this case, if no trigger frame is detected (NO in S1503), AP101 does not switch to communication using the second communication method and maintains communication using the first communication method. When AP101 detects a trigger frame (YES in S1503), it switches to communication using the second communication method (S1504). For example, AP101 switches the carrier sensing channel from PCH to SPCH. AP101 communicates data with STA110 using NPCA. When NPCA SP is about to end (YES in S1505), AP101 switches from communication using the second communication method to communication using the first communication method (S1506). For example, AP101 switches the carrier sensing channel from NPCH to PCH.

[0077] AP101 may determine whether to continue communication using SP-based NPCA after the NPCA SP has finished (S1507). If AP101 determines to continue communication using SP-based NPCA (YES in S1507), it returns to S1501 and continues processing. If AP101 determines not to continue communication using SP-based NPCA (NO in S1507), it recollects the OBSS TWT information and determines whether to change the NPCA SP (S1508). For example, AP101 may determine whether to continue the NPCA SP based on the radio quality during the NPCA SP. As an example, AP101 may determine not to continue communication using SP-based NPCA if values ​​indicating radio quality, such as the number of frame retransmissions or the percentage of transmission opportunities obtained during the NPCA SP, fall below a threshold. AP101 may also periodically recollect the OBSS TWT information and change the NPCA SP based on the updated OBSS TWT information. Furthermore, if AP101 obtains new TWT information from another AP, it may change the NPCA SP based on the updated OBSS TWT information. If AP101 recollects the OBSS TWT information (YES in S1508), it proceeds to S1403 and continues processing. If AP101 does not recollect the OBSS TWT information (NO in S1508), it notifies STA110 that it will terminate communication using SP-based NPCA (S1509) and terminates communication using SP-based NPCA (S1510). Then, AP101 performs data communication with STA110 using the first communication method without using NPCA.

[0078] Figure 16 shows an example of a processing flow executed by STA110. This processing flow may be executed based on the fact that STA110 has established a connection with AP101. STA110 negotiates NPCA with AP101 (S1601). For example, STA110 may decide whether to communicate with AP101 using SP-based NPCA, TXOP-based NPCA, or not to communicate using NPCA at all. STA110 may also decide to communicate using both SP-based NPCA and TXOP-based NPCA.

[0079] If NPCA negotiations determine that SP-based NPCA should be implemented (YES in S1602), STA110 will execute communication using SP-based NPCA based on notification from AP101. STA110 may also collect OBSS TWT information based on instructions from AP101 (YES in S1603) (S1604). In this case, STA110 will report the collected OBSS TWT information to the AP (S1604). When STA110 receives information from AP101 to identify an NPCA SP (YES in S1605), it will execute communication using NPCA at the identified NPCA SP (S1606). For example, STA110 may receive integrated OBSS TWT information from AP101 as information to identify an NPCA SP. Furthermore, STA110 may receive TWT information obtained by AP101 from other APs, as well as information necessary for STA110 to determine whether or not to perform communication using SP-based NPCA. In this case, STA110 determines whether or not to perform communication using NPCA based on this information. For example, STA110 can determine whether or not to perform communication using NPCA by generating integrated OBSS TWT information in its own device and determining whether or not the TWT SP included in the integrated OBSS TWT information satisfies the conditions received from AP101. STA110 can also identify the NPCA SP based on the generated integrated OBSS TWT information. When the period of the NPCA SP arrives, STA110 switches from the first communication method to the second communication method and performs communication using NPCA. If STA110 does not receive a notification from AP indicating the start of communication using NPCA or information identifying the NPCA SP (NO in S1605), it maintains communication using the first communication method without performing communication using NPCA (S1609).

[0080] If the NPCA negotiation determines that TXOP-based NPCA should be performed (NO in S1602 and YES in S1607), STA110 will perform communication using TXOP-based NPCA (S1608). If the NPCA negotiation determines that NPCA should not be performed (NO in S1602 and NO in S1607), STA110 will maintain communication using the first communication method without performing communication using NPCA (S1609).

[0081] The operation of STA110 when performing SP-based NPCA communication (S1606) will be explained using Figure 17. In Figure 17, the same processes as in Figure 15 are given the same reference numbers and their explanations are omitted. That is, STA110 operates in the same way as AP101 in NPCA SP and communicates data with AP101 (S1501~S1504). When it is time for NPCA SP to end (YES in S1505), STA110 switches to communication using the first communication method (S1506) and may receive a notification from AP101 indicating the end of communication using SP-based NPCA (S1701). In this case, STA110 terminates communication using SP-based NPCA (S1510) and maintains communication using the first communication method.

[0082] (modified version) The above explanation used an example in which AP101 obtains TWT information of OBSS from AP102. In this modified example, we will explain an example in which AP101 collects TWT information set in OBSS (network 123) configured by AP103 in Figure 1. As mentioned above, AP101 does not communicate directly with AP103. Therefore, AP101 collects TWT information set in network 123 by receiving frames transmitted in network 123. AP101 can also request STA110 to collect and report TWT information set in network 123. Based on the OBSS TWT information collected in this way, AP101 can determine whether or not to perform communication using SP-based NPCA.

[0083] Figure 18 shows an example sequence when AP101 performs communication using SP-based NPCA based on TWT information configured in network 123. In Figure 18, configurations similar to those in Figure 6 are given the same reference numbers and their explanations are omitted. After NPCA negotiation with STA111 and STA112 (F601), AP101 receives frames transmitted in network 123 (F603-F606). For example, AP101 and STA110 may receive TWT Setup frames (TWT Request frames, TWT Response frames) and Beacon frames transmitted in network 123. Note that Figure 18 shows an example where frames transmitted from AP103, STA115, and STA116 are received by AP101, STA111, and STA112, respectively. However, frames transmitted from some communication devices participating in network 123 may not be received by some communication devices participating in network 121. For example, in the configuration shown in Figure 1, AP101 and STA111 may not be able to receive frames transmitted from STA115 and STA116. In this case, AP101 can obtain the TWT information for network 123 by requesting STA112 to collect the TWT information set for network 123 and report it to AP101 (F1801). STA110 collects the TWT information set for network 123 based on the frames it receives and reports it to AP101 (F1802). AP101 generates integrated OBSS TWT information based on the TWT information for network 123 collected based on the frames it receives and the TWT information reported by STA110 (F608). For example, STA110 reports to AP101 using a frame containing TWT elements included in the received frame. AP101 can generate integrated OBSS TWT information based on the information contained in the collected TWT elements. AP101 and STA110 can exchange TWT information set on network 123 using frames for exchanging OBSS TWT information.The frame used for exchanging information in OBSS TWT may be a new type of Action frame defined in the IEEE 802.11 standard series.

[0084] In network 123 in Figure 18, AP123 sends a Trigger frame within the configured TWT SP period (F1803). Upon receiving the Trigger frame, STA115 responds with a PS-Poll frame (F1804). Upon receiving the Trigger frame, STA116 responds with a QoS Null frame (F1805). AP101 sends data frames to STA115 and STA116 based on the received PS-Poll and QoS Null frames (F1806). STA115 and STA116 each provide acknowledgments for the data frames they received (F1807). Acknowledgments may be made using BlockACK frames. Meanwhile, AP101 and STA110 switch from communication using the first communication method to communication using the second communication method based on having received the Trigger frame transmitted in network 123 within the NPCA SP period (F610). AP101 and STA110 maintain communication using the first communication method if they do not receive a Trigger frame transmitted on network 123 within the period of NPCA SP. In this way, by switching to communication using the second communication method based on the transmission of a Trigger frame and the actual commencement of communication in the TWT SP set in OBSS, communication can be carried out efficiently. For example, if AP101 and STA111 do not receive a Trigger frame, they can communicate using a wider frequency band by using the first communication method including PCH.

[0085] Furthermore, when AP101 and STA110 switch from communication using the first communication method to communication using the second communication method based on the receipt of a Trigger frame in OBSS, the switch may be configured to occur only when certain conditions are met. The predetermined conditions are that the TWT set in network 123 is a trigger-enabled TWT. Another predetermined condition may be that the STA performing communication using SP-based NPCA can receive the Trigger frame transmitted by AP103. When these predetermined conditions are met, AP101 can synchronize the timing of communication using NPCA with STA110. AP101 can notify STA110 that it should switch from the first communication method to the second communication method based on the receipt of the Trigger frame. Thus, the operation by which AP101 and STA110 switch to the second communication method upon detection of the transmission of a Trigger frame in OBSS can be said to be the operation of activating NPCA using a Control frame of the IEEE802.11 standard. This configuration allows AP101 and STA110 to maintain communication using the first communication method for a longer period, potentially improving the efficiency of frequency resource utilization.

[0086] As described above, according to this embodiment, the communication device 100 defines an NPCA SP for communication using NPCA with the other party's communication device, and performs communication using NPCA during that period. The NPCA SP may be set based on the period for which the TWT SP is set in OBSS. The communication device 100 also determines whether or not to perform SP-based NPCA communication based on the duration of the TWT SP set in OBSS. This makes it possible to avoid a situation where data communication is not possible due to a short NPCA SP after switching from communication using the first communication method to communication using the second communication method. Furthermore, the communication device 100 can create integrated OBSS TWT information based on the information of multiple TWTs, and set the period corresponding to the extended TWT SP, which is a combination of multiple TWT SPs included in the integrated OBSS TWT information, as the NPCA SP. This makes it possible to avoid switching between the first and second communication methods in a short period of time. With this configuration, the communication device 100 can increase its chances of acquiring transmission rights by using NPCA during periods of increased traffic in the OBSS, thereby enabling efficient use of frequency resources. Furthermore, since interference in the OBSS is reduced, the likelihood of communication being executed on schedule in the OBSS is increased. Thus, this embodiment enables effective utilization of frequency resources in both the BSS and the OBSS.

[0087] In this embodiment, the communication method that does not use a PCH is exemplified as NPCA, but it is not limited to this, and may be called, for example, Secondary Primary Channel Access. In this embodiment, the channel used to determine whether or not to transmit using an NPCH is exemplified as SPCH for convenience, but it is not limited to this. It may also be called PSCH (Primary Secondary Channel) to mean the channel with the highest priority for determining whether or not to transmit among multiple NPCHs. In any case, it means that it is the channel that should be used to determine whether or not to transmit using an NPCH. Also, the configurations of frames, information elements, fields, subfields, etc. described in this embodiment are illustrative and may be called by different names. In addition, some information may be omitted from each configuration, or other information may be included. Integrated TWT and Extended TWT SP may be called by other names.

[0088] 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., an ASIC) that implements one or more functions.

[0089] (Summary of the embodiments) At least some of the embodiments described above can be summarized as follows: (Item 1) A communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, A first communication method configured to enable communication by bonding a first channel with one or more second channels different from the first channel, comprising: a first communication method that acquires transmission rights and performs communication using the first channel; and a second communication method that, when the first channel cannot be used, acquires transmission rights using a third channel included in the second channel and performs communication using at least the third channel; and a communication means that performs communication using a plurality of communication methods, An acquisition means for acquiring information regarding the Target Wake Time Service Period (TWT SP) set in an Overlapping BSS (OBSS) that uses the first channel and covers at least a portion of the geographical area covered by the Basic Service Set (BSS) provided by the communication device, A determination means that determines whether or not to perform communication using the second communication method during the period in which the TWT SP is set, based on the duration of the TWT SP set in the OBSS, The system includes a notification means for notifying the other communication device that communication using the second communication method will be performed based on the result of the determination. A communication device characterized by the following features. (Item 2) The system further includes a means for specifying the period during which communication using the second communication method is performed. A communication device as described in item 1, characterized by the features described herein. (Item 3) The communication means, during the specified period, will perform communication using the second communication method without attempting to acquire the right to transmit using the first channel in the first communication method. A communication device as described in item 2, characterized by the features described herein. (Item 4) The acquisition means acquires information regarding the TWT SP set in the OBSS from the access points that constitute the OBSS. A communication device characterized by any one of items 1 to 3. (Item 5) The acquisition means acquires information regarding the TWT SP set in the OBSS by the communication device or other communication device receiving the wireless frame transmitted in the OBSS. A communication device characterized by any one of items 1 to 4. (Item 6) The determination means determines, based on the fact that the duration of the TWT SP set in the OBSS is longer than a predetermined value, that communication using the second communication method will be performed during the period in which the TWT SP is set. A communication device characterized by any one of items 1 to 5. (Item 7) The determination means determines, based on the fact that the sum of the durations of the TWT SPs set in the OBSS over a certain period is longer than a predetermined value, that communication using the second communication method will be performed during the period in which the TWT SPs are set. A communication device characterized by any one of items 1 to 6. (Item 8) The determination means performs the determination based on the period length of the TWT SP that is set periodically among the TWT SP set in the OBSS. A communication device characterized by any one of items 1 to 7. (Item 9) The determination means performs the determination based on the duration of the TWT SPs set in the OBSS in which a predetermined number of terminal devices participate. A communication device characterized by any one of items 1 to 8. (Item 10) When a first TWT and a second TWT are set in the OBSS, the determination means further performs the determination based on the duration of the period covering the first TWT SP of the first TWT, the second TWT SP of the second TWT, and the period between the first TWT SP and the second TWT SP. A communication device characterized by any one of items 1 to 9. (Item 11) The notification means provides the notification which further includes information indicating that, upon the start of the specified period, a switch should be made from communication using the first communication method to communication using the second communication method. A communication device according to item 2 or 3, characterized by the features described herein. (Item 12) The notification means provides the notification, which further includes information indicating that, upon receiving a Trigger frame transmitted in the OBSS within the specified period, a switch should be made from communication using the first communication method to communication using the second communication method. A communication device according to item 2 or 3, characterized by the features described herein. (Item 13) A control method performed by a communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, A first communication method configured to enable communication by bonding a first channel with one or more second channels different from the first channel, comprising: a first communication method that acquires transmission rights and performs communication using the first channel; and a second communication method that, when the first channel cannot be used, acquires transmission rights using a third channel included in the second channel and performs communication using at least the third channel; and a communication process that performs communication using a plurality of communication methods, An acquisition step of acquiring information regarding the Target Wake Time Service Period (TWT SP) set in an Overlapping BSS (OBSS) that uses the first channel and covers at least a portion of the geographical area covered by the Basic Service Set (BSS) provided by the communication device, A determination step of determining whether or not to perform communication using the second communication method during the period in which the TWT SP is set, based on the duration of the TWT SP set in the OBSS, The process includes a notification step of notifying the other communication device that communication will be performed using the second communication method based on the result of the determination. A control method characterized by the following: (Item 14) A program to cause a computer to function as one of the means of a communication device described in any one of items 1 through 12.

[0090] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0091] 101:AP, 102:AP, 103:AP, 111:STA, 112:STA, 113:STA, 114:STA, 115:STA, 116:STA, 121:Network, 122:Network, 123:Network, 141:DS

Claims

1. A communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, A first communication method configured to enable communication by bonding a first channel with one or more second channels different from the first channel, comprising: a first communication method that acquires transmission rights and performs communication using the first channel; and a second communication method that, when the first channel cannot be used, acquires transmission rights using a third channel included in the second channel and performs communication using at least the third channel; and a communication means for performing communication using a plurality of communication methods, An acquisition means for acquiring information regarding a Target Wake Time Service Period (TWT SP) set in an Overlapping BSS (OBSS) that covers at least a portion of the geographical area covered by the Basic Service Set (BSS) provided by the communication device and uses the first channel, A determination means for determining whether or not to perform communication using the second communication method during the period in which the TWT SP is set, based on the duration of the TWT SP set in the OBSS, The system includes a notification means for notifying the other communication device that communication using the second communication method will be performed based on the result of the determination. A communication device characterized by the following features.

2. The system further includes a means for specifying the period during which communication using the second communication method described above is performed. The communication device according to feature 1.

3. The communication means, during the specified period, performs communication using the second communication method without attempting to acquire the right to transmit using the first channel in the first communication method. The communication device according to feature 2.

4. The acquisition means acquires information regarding the TWT SP set in the OBSS from the access points that constitute the OBSS. The communication device according to feature 1.

5. The acquisition means acquires information regarding the TWT SP set in the OBSS when the communication device or another communication device receives a wireless frame transmitted by the OBSS. The communication device according to feature 1.

6. The determination means determines, based on the fact that the duration of the TWT SP set in the OBSS is longer than a predetermined value, that communication using the second communication method will be performed during the period in which the TWT SP is set. The communication device according to feature 1.

7. The determination means determines, based on the fact that the sum of the durations of the TWT SPs set in the OBSS over a certain period is longer than a predetermined value, that communication using the second communication method will be performed during the period in which the TWT SPs are set. The communication device according to feature 1.

8. The determination means performs the determination based on the period length of the TWT SP that is set periodically among the TWT SPs set in the OBSS. The communication device according to feature 1.

9. The determination means performs the determination based on the duration of the TWT SPs set in the OBSS in which a predetermined number of terminal devices participate. The communication device according to feature 1.

10. If a first TWT and a second TWT are set in the OBSS, the determination means further performs the determination based on the duration of the period covering the first TWT SP of the first TWT, the second TWT SP of the second TWT, and the period between the first TWT SP and the second TWT SP. The communication device according to feature 1.

11. The notification means provides the notification which further includes information indicating that, upon the start of the specified period, the communication should be switched from the first communication method to the second communication method. The communication device according to feature 2.

12. The notification means provides the notification, which further includes information indicating that, upon receiving a Trigger frame transmitted by the OBSS within the specified period, a switch should be made from communication using the first communication method to communication using the second communication method. The communication device according to feature 2.

13. A control method performed by a communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, A first communication method configured to enable communication by bonding a first channel with one or more second channels different from the first channel, comprising a first communication method that acquires transmission rights and performs communication using the first channel, and a second communication method that, when the first channel cannot be used, acquires transmission rights using a third channel included in the second channel and performs communication using at least the third channel, and a communication process that uses a plurality of communication methods, An acquisition step of acquiring information regarding the Target Wake Time Service Period (TWT SP) set in an Overlapping BSS (OBSS) that covers at least a portion of the geographical area covered by the Basic Service Set (BSS) provided by the communication device and uses the first channel, A determination step of determining whether or not to perform communication using the second communication method during the period in which the TWT SP is set, based on the duration of the TWT SP set in the OBSS, The process includes a notification step of notifying the other communication device that communication will be performed using the second communication method based on the result of the determination. A control method characterized by the following:

14. A program for causing a computer to function as each of the means of the communication device described in claim 1.

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