Communication device, control method, and program

Abstract

This communication device that communicates with another communication device by using an IEEE802.11 standard series-compliant wireless frame: performs communication by using a plurality of communication schemes including a first communication scheme which is configured such that communication can be performed by bonding a first channel with one or more of second channels different from the first channel, and in which a transmission right is obtained by using the first channel to perform the communication, and a second communication scheme in which, when the first channel cannot be used, a transmission right is obtained by using a third channel included in the second channels to perform communication by using at least the third channel; acquires information relating to a target wake time service period (TWT SP) set in an overlapping basic service set (OBSS) that covers at least a part of a geographical range covered by a basic service set (BSS) provided by the communication device and uses the first channel; determines, on the basis of the period length of the TWT SP set in the OBSS, whether or not to perform communication using the second communication scheme in a period in which the TWT SP is set; and, on the basis of the determination result, notifies the other communication device that the communication using the second communication scheme is performed.

Description

Communication Device, Control Method, and Program

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

[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, etc. 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 technology for communicating using other channels 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.

[0004] U.S. Patent Application Publication No. 2024 / 0205732

[0005] The present disclosure provides a technology for efficiently using wireless resources in a communication system using a communication link composed of a plurality of channels.

[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, and acquisition means for 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, and the TWT set in the OBSS The system includes 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 SP, 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.

[0007] According to this disclosure, wireless resources can be efficiently utilized in a communication system that uses a communication link composed of multiple channels.

[0008] Other features and advantages of this disclosure will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are given the same reference numeral.

[0009] The attached drawings are included in the specification and constitute part thereof, illustrating embodiments of the present disclosure and are used together with the description to explain the principles of the present disclosure. Figure 1 is a diagram showing an example configuration of a wireless communication system. Figure 2A is a schematic diagram showing an example of a time chart when a communication device transmits data. Figure 2B is a schematic diagram showing an example of a time chart when a communication device transmits data. Figure 3 is a diagram showing an example of the hardware configuration of a communication device. Figure 4 is a diagram showing an example of the functional configuration of an AP. Figure 5 is a diagram showing an example of the functional configuration of an STA. Figure 6 is a diagram showing an example of a sequence executed between the AP and the STA. Figure 7 is a diagram showing an example of the configuration of a TWT element. Figure 8A is a diagram showing an example of the configuration of a Control field. Figure 8B is a diagram showing an example of the configuration of a Control field. Figure 9 is a diagram showing an example of the configuration of a TWT Parameter Information field. Figure 10 is a diagram showing an example of the configuration of a TWT Parameter Information field. Figure 11A is a diagram showing an overview of a method for determining whether or not to execute communication using an SP-based NPCA. Figure 11B is a diagram illustrating an overview of the method for determining whether or not to execute communication using SP-based NPCA. Figure 11C is a diagram illustrating an overview of the method for determining whether or not to execute communication using SP-based NPCA. Figure 12 is a diagram illustrating an overview of the method for generating integrated TWT. Figure 13 is a diagram illustrating an overview of the method for generating integrated TWT. Figure 14 is a diagram illustrating an example of the processing flow executed by AP. Figure 15 is a diagram illustrating an example of the processing flow executed by AP. Figure 16 is a diagram illustrating an example of the processing flow executed by STA. Figure 17 is a diagram illustrating an example of the processing flow executed by STA. Figure 18 is a diagram illustrating an example of the sequence executed between AP and STA.

[0010] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claims. While the embodiments describe multiple features, not all of these features are necessary, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0011] (System Configuration) Figure 1 shows an example of the configuration of a wireless communication system according to this embodiment. The wireless communication system includes, for example, an access point (AP) 101 and stations (STA) 111 and STA 112. AP 101, STA 111, and STA 112 are communication devices capable of performing wireless communication in accordance with the IEEE 802.11 standard series. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. Figure 1 shows a configuration in which STA 111 and STA 112 participate in a network 121 provided by AP 101. Network 121 may also be called a Basic Service Set (BSS). BSS may refer to a collection of communication devices consisting of AP101 and STAs participating in the network 121 provided by AP101, or it may refer to the geographical range in which AP101 can communicate with STAs participating in the network 121 provided by AP101. The geographical range in which AP101 can communicate with STAs participating in the network 121 provided by AP101 may be called the Basic Service Area (BSA). In Figure 1, the network 121 is shown as having one AP101 and two STAs 111 and 112, but for example, there may be multiple APs in the network 121, and there may be one or more STAs. Also, each STA may be connected to one AP, or one STA may be connected to multiple APs.

[0012] In Figure 1, near network 121, there are two networks: network 122, consisting of AP 102, STA 113, and STA 114; and network 123, consisting of AP 103, STA 115, and STA 116. AP 101 is assumed to be communicably connected to AP 102 via a Distribution System (DS) 141, which is configured as either a wired or wireless line. DS 141 may be a wired communication line such as Ethernet® or a telephone line. Alternatively, DS 141 may be a wireless communication line such as LTE (Long-Term Evolution) or WiMAX (Worldwide Interoperability for Microwave Access). DS 141 may also be a wireless communication line compliant with the IEEE 802.11 standard series. Furthermore, 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 standard series, similar to AP101. Also, STA113 to STA116 are communication devices capable of performing wireless communication compliant with the IEEE 802.11 standard series, similar to 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 the OBSS covers at least a portion of the geographical area covered by the own BSS and is using a PCH, interference may occur in the own BSS.In this embodiment, the operation of AP101, STA111, and STA112 in network 121 will be described. This operation is similarly applicable to the operation of AP102, STA113, and STA114 in network 122, and the operation of AP103, STA115, and STA116 in network 123. STA111 and STA112 may be referred to as STA110 without distinction. Also, AP101 and STA110 may be referred to as communication device 100 without distinction.

[0013] 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 (Gigabits 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 a communication method compliant with this standard may be called a 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, etc., may be changed to different names once the standard is finalized. Also note that this specification and the claims attached herein are applicable to communication devices using all successor standards to IEEE 802.11be. Furthermore, the communication device 100 may correspond to 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. Furthermore, the communication device 100 may support other communication standards such as Bluetooth®, NFC, UWB, ZigBee, and MBOA. UWB is an abbreviation for Ultra Wide Band, and MBOA is an abbreviation for Multi Band OFDM Alliance. NFC is an abbreviation 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, etc.STA110 is a terminal device such as a camera, tablet, smartphone, PC, mobile phone, video camera, headset, smart glasses, HMD (head-mounted display), or other wearable device, but is not limited to these. STA110 may be an information processing device such as a wireless chip capable of performing wireless communication that supports the transmission and reception of PPDUs compliant with the IEEE 802.11bn standard. In this case, it can be configured to perform various controls by hardware circuits inside the wireless chip. It can also be configured so that various processes are performed by the cooperation of a processor such as an ASIP, memory, and hardware circuits inside the wireless chip. ASIP is an abbreviation for Application-specific instruction set processor.

[0014] The communication device 100 can communicate using radio signals in frequency bands such as the 2.4 GHz band, 3.6 GHz band, 5 GHz band, 6 GHz band, and millimeter wave bands such as the 45 GHz band and 60 GHz band. The frequency bands used by the communication device 100 are not limited to these, and may include, for example, the Sub1 GHz band. Furthermore, the communication device 100 can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The bandwidths used by the communication device 100 are not limited to these, and may include, for example, 240 MHz or 4 MHz. Note that the IEEE 802.11 standard series specifies frequency channels using a bandwidth of 20 MHz as basic channels in frequency bands such as the 2.4 GHz, 5 GHz, and 6 GHz bands. Furthermore, this standard defines multiple usable channels in the 2.4 GHz, 5 GHz, and 6 GHz 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 within this bandwidth may be continuous or discontinuous on the frequency axis. AP101 and STA102 may also be AP MLDs (Multi-Link Devices) and STA MLDs, respectively, that support Multi-Link, which establishes and communicates through multiple links simultaneously.

[0015] 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 its own device. 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 does not transmit based on information such as the Duration field of the received signal is called setting the NAV. That is, until the NAV set for 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.

[0016] The communication device 100 can, for example, determine whether transmission is possible using only the 20 MHz bandwidth Primary Channel (PCH) included in a 160 MHz bandwidth link when communicating. The PCH is one of the eight 20 MHz bandwidth channels that make up the 160 MHz bandwidth link. AP 101 can notify STA 110 of the PCH using a Beacon frame that is broadcast periodically. For example, the IEEE 802.11 standard series states that the communication device 100 can start transmission if it determines that transmission is possible as a result of performing carrier sensing on the PCH over a predetermined period of time. The predetermined period is determined by the Interface 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 for 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 by channel bonding using those idle channels and the PCH. PIFS is an abbreviation for Priority Interface Space. Also, if the communication device 100 determines that transmission is impossible as a result of carrier sensing on the PCH, it may postpone transmission even if other channels included in the same link are idle. Each of the channels other than the PCH that constitute a single link may be called a non-primary channel (NPCH). Non-primary channels may also be called secondary channels (SCH).

[0017] In communication device 100, if a signal is being received on a certain channel, and a signal is being transmitted on another channel (for example, 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 processing 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 a 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.

[0018] However, as the IEEE 802.11 standard series expands, the bandwidth used in a single link has increased, and as a communication method that always uses the PCH, as described above, may not be able to use frequency resources efficiently. For example, if other idle channels (NPCHs) are not used based on the PCH being busy, it can hinder the efficient use of the frequency resources of the entire link. Figure 2A shows an example of a time chart when STA102 transmits data to AP101. In Figure 2A, 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 2B shows another example of a time chart when STA102 transmits data to AP101. In Figure 2B, while STA111 is performing carrier sensing on the PCH, the PCH is being used by another network located geographically near STA111 (for example, network 122 in Figure 1). 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 20 MHz bandwidth PCH is being used by another network, the remaining 140 MHz of idle NPCHs cannot be utilized, resulting in inefficient use of frequency resources.

[0019] 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 Secondary Primary Channels (SPCHs). SPCHs are channels used to acquire transmission rights for transmission using NPCHs when the PCH is busy. SPCHs may be called by other names, for example, Primary Secondary Channels (PSCHs). 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 is determined 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 its own BSS communication device or by the OBSS communication device by identifying the source of the signal being communicated on the PCH. Furthermore, the determination of whether the SPCH is transmittable can be performed in the same way as the determination of whether 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 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. In addition, in communication using the first communication method, the communication device 100 may perform communication 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 used by OBSS and the SPCH is available. With a configuration that uses multiple communication methods including these, the communication device 100 can communicate efficiently by using NPCH, which has little impact on the PCH, even when the PCH is in use.

[0020] 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 the OBSS, communication using NPCA may fail depending on the geographical location of the communication devices 100. For example, depending on the geographical location of AP 101 and STA 110, a signal from the 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 the OBSS performs NPCA using the SPCH, communication using NPCA may fail because the other communication device is not receiving on the SPCH. In such a situation, when the communication device 100 performs communication using NPCA, it may exchange signals to confirm that the other communication device is receiving on the 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 during which communication using NPCA is possible. 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 the PCH and NPCH, respectively. This can reduce the efficiency of frequency resource utilization.

[0021] 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 the AP to set a predetermined period for communication with STAs that perform power-saving operation. STAs that perform power-saving operation enter the AWAKE state during the predetermined period set by the AP. STAs that perform power-saving operation may enter the 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 is defined as the AP setting the period during which the STA connected to its device should be in the AWAKE state using parameters such as TWT and TWT SP. The period during which the STA maintains the AWAKE state within the set TWT is called the TWT SP, and the length of the TWT SP is called the TWT SP duration. Furthermore, information related to the set TWT is referred to as TWT information. TWT information may include the duration of the TWT SP, the start timing of the TWT SP, the interval between TWT SPs, and TWT identification information. In a BSS where the TWT is set, intensive communication may occur between the STA performing power-saving operation and the AP during the TWT SP. Therefore, when a TWT is set in OBSS (network 122, etc.), AP101, STA111, and STA112 may have a lower percentage of the right to transmit in the PCH during the periods corresponding to each TWT SP compared to other periods. Accordingly, the communication device 100 may set the periods corresponding to the TWT SPs of the TWT set in OBSS as periods for communication using NPCA between its own device and the other party's communication device.The period during which communication is performed using NPCA may be called an NPCA Service Period (NPCA SP). This allows the 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 an NPCA SP, the communication device 100 can exchange data by omitting the exchange of ICF and ICR, assuming that the other party's communication device is receiving on the SPCH. In addition, by not using the PCH during TWT SPs, when communication is concentrated on the OBSS, the communication device 100 can avoid interfering with the OBSS. Furthermore, 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. The communication device 100 can avoid interfering with the communication of high-priority traffic in the OBSS by performing communication using NPCA during the period when R-TWT SP is set in the OBSS.

[0022] The communication device 100 acquires information about the TWT set in the OBSS and determines whether or not to use the second communication method (NPCA) for communication during the period in which the TWT SP is set, 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 the 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 during 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 in which the communication device 100 can use communication will be further shortened. The communication device 100 compares the duration of the TWT SP in the 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, communication using NPCA can be performed. The communication device 100 can also identify the period for performing communication using NPCA (NPCA SP) based on the TWT SP set in the OBSS and notify the other party's communication device. The communication device 100 and the other party's 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 the 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 Transaction Opportunity. These NPCA methods may be referred to by other names. An example configuration and processing example of the communication device 100 operating as described above will be explained below.

[0023] (Device Configuration) Figure 3 shows an example of the hardware configuration of the communication device 100 of this embodiment. As an example of its hardware configuration, the communication device 100 has, 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.

[0024] 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.

[0025] 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 storage unit 301. Alternatively, the control unit 302 may control the entire communication device 100 through cooperation between the control program stored in the storage 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 that can be implemented as a multi-core system, it may be configured so that the entire communication device 100 is controlled by multiple processors.

[0026] 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.

[0027] 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.

[0028] The communication unit 306 controls wireless communication in accordance with the IEEE 802.11bn standard. In addition to the IEEE 802.11bn standard, the communication unit 306 may also control wireless communication in accordance 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 have one or more processors and memory. If the communication device 100 supports other wireless communication standards such as NFC and Bluetooth standards, or wired communication such as wired LAN, in addition to the IEEE 802.11bn standard, the communication unit 306 may also control communication in accordance with these communication standards. Furthermore, if the communication device 100 can perform wireless communication in accordance 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 party's 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.

[0029] Antenna 307 is an antenna capable of communication in millimeter waves such as the 2.4 GHz band, 5 GHz band, 6 GHz band, 45 GHz band, and 60 GHz band. 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, or 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.

[0030] (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.

[0031] 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 a first communication method or a second communication method based on their respective statuses. For example, when the wireless communication control unit 401 uses TXOP-based NPCA for 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 communicates using the second communication method based on whether the predetermined conditions are met. On the other hand, when the wireless communication control unit 401 uses SP-based NPCA for communication, it uses the second communication method during the NPCA SP period. Also, the wireless communication control unit 401 may use the first communication method outside of the NPCA SP period.

[0032] 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 AP 102 via DS 141. The information acquisition unit 402 can also collect TWT information set in network 123 by receiving frames transmitted in network 123, which is configured by AP 103. Furthermore, the information acquisition unit 402 can acquire TWT information set in OBSS from reports from STA 110.

[0033] The NPCA control unit 403 determines whether or not to perform communication using NPCA. For example, based on capability information obtained from STA 110, the NPCA control unit 403 may decide whether to perform communication using SP-based NPCA, communication using TXOP-based NPCA, or 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 of the TWT SP set in the OBSS. For example, if the duration 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 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.

[0034] 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 OBSS TWT SP as the NPCA SP. The Information Notification Unit 405 notifies the STA 110 of information related to communication using NPCA. For example, the Information Notification Unit 405 may notify the STA 110 that communication using SP-based NPCA will be performed. The Information Notification Unit 405 may also notify the STA 110 of information for identifying the NPCA SP.

[0035] 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.

[0036] The wireless communication control unit 501 may be configured in the same way as the wireless communication control unit 401. The information acquisition unit 502 acquires information from AP 101 regarding communication used for NPCA. For example, the information acquisition unit 502 may acquire from AP 101 information indicating that communication using SP-based NPCA is to be performed. The information acquisition unit 502 may also acquire from AP 101 information for identifying the NPCA SP. Furthermore, the information acquisition unit 502 may acquire TWT information set in OBSS by receiving frames transmitted in OBSS.

[0037] 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 a schedule for NPCA SPs in its own device. For example, the NPCA control unit 503 can set a schedule for an NPCA SP identified based on information for identifying an NPCA SP obtained by the information acquisition unit 502 from AP. When an 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 an 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.

[0038] The NPCA SP Identification Unit 504 identifies an NPCA SP. For example, if the NPCA SP Identification Unit 504 receives information from AP 101 for identifying an NPCA SP, it can identify the NPCA SP based on the received information. Also, if the NPCA SP Identification Unit 504 receives information from AP 101 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 AP 101 of information regarding communication using NPCA. For example, the Information Notification Unit 505 can notify AP 101 of its own device capability information regarding NPCA. Also, the Information Notification Unit 505 can notify AP 101 of TWT information obtained from frames received from OBSS.

[0039] (Processing Flow) Below, several examples of the processing flow performed by AP101 and STA110 in this embodiment will be described. First, an overview of communication using SP-based NPCA performed between AP101 and STA110 will be explained using Figure 6. 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 the 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 perform communication using the determined communication method. In this example, it is assumed that AP101 has obtained capability information from both STA111 and STA112 indicating support for the SP-based NPCA method. Note that 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 using these frames indicating whether STA110 is capable of performing communication using NPCA. Furthermore, AP101 can notify STA110 of capability information indicating whether or not its device is capable of performing communication using NPCA, using these frames and Beacon frames.

[0040] 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 also 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, AP101 decides to perform communication using SP-based NPCA between STA111 and STA112, respectively. AP101 may also determine the SPCH when performing communication using SP-based NPCA with STA110.

[0041] 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 transmission 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 information set in network 122. AP102 sends an acknowledgment for the message received from AP101.

[0042] Subsequently, AP102 may set TWT with STA113 and STA114. The setting of TWT can be performed by negotiation between AP102 and STA113 and STA114 using a TWT Setup frame. In the negotiation, the period (TWT SP) for which each STA should maintain the AWAKE state 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 to be set between AP102 and STA113, the interval between TWT SPs, etc. When AP102 receives a TWT Request frame, it responds using a TWT Response frame (F605). The TWT Response frame may contain information that specifies the duration of the TWT SP set by AP102 with STA113, the interval between TWT SPs, etc. This allows a TWT to be set between AP102 and STA113. STA113 may enter an AWAKE state during the duration of the set TWT SP and a DOZE state during the interval between TWT SPs. The AWAKE state means that STA113 can communicate with AP102, while the DOZE state means that 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 TWT Response frames, which are transmitted without receiving a TWT Request frame, may be called Unsolited TWT Response frames. Through communication of Unsolited TWT Response frames, a TWT may be established between AP102 and STA114. The Unsolited TWT Response frame may contain information that specifies the duration of the TWT SPs and the interval between TWT SPs of the TWT that AP102 establishes with STA114.Furthermore, AP102 may use a Beacon frame to set a TWT to be used by multiple STAs in network 122. Such a TWT used by multiple STAs may be called a Broadcast TWT. In this case, the Beacon frame may include information specifying the duration and interval of the TWT SP. Information regarding the timing of the transmission of the Beacon frame containing TWT information related to the Broadcast TWT may be exchanged during TWT negotiation between AP102 and STA113 and 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 TWT set 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 period during which TWT SPs are configured, and the interval between TWT SPs. In addition, AP102 may notify AP101 of information that determines whether or not AP102 will send a Trigger frame when each TWT SP is started.

[0043] AP101 determines whether or not to use SP-based NPCA communication during the TWT SP period of a given 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. AP101 also determines that SP-based NPCA communication should be performed if the duration of the TWT SP is longer than a predetermined threshold. AP101 can 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 of information created by AP101 using information from one or more TWTs obtained from other APs, as described later. The integrated OBSS TWT information may be created under a different name as information for identifying NPCA SPs that perform communication using SP-based NPCA. 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 is longer than 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 NPCA SPs. When STA111 and STA112 receive integrated OBSS TWT information or information generated based on the integrated OBSS TWT information from AP101, they prepare to communicate using SP-based NPCA. For example, STA111 and STA112 set the NPCA SP identified based on the received information in their own devices.

[0044] When AP101, STA111, and STA112 become NPCA SPs, they 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 SPs start, taking into account the switching time required for switching from the first communication method 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. However, STA111 may also transmit data to AP101, and AP101 may transmit data to STA112. When the 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 the NPCA SP ends, taking into account the switching time required to switch from the second communication method to the first communication method in their own devices. AP101 and STA111 and STA112 exchange data using the first communication method (F618). Meanwhile, in network 122 configured by AP102, communication using the first communication method may occur at the TWT SP of the configured TWT. For example, data may be exchanged between AP102 and STA113 and STA114 at the TWT SP (F613-F616). The duration of the TWT SP of the configured TWT 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 at the TWT SP in OBSS is protected.Also, the period of the NPCA SP may start earlier and end earlier than the period of the TWT SP. As a result, even if a switching time occurs when switching from communication using the second communication method to communication using the first communication method, communication using the first communication method can be started in the network 121 along with the end of the TWT SP of the OBSS. In FIG. 6, a situation where one TWT is set in the network 122 is shown, but in one TWT, the TWT SP can be periodically set. Also, a plurality of TWTs can be set in one network. For example, different individual TWTs can be set between the AP 102 and each of the STAs 113 and 114. Further, in addition to the individual TWTs set between the AP 102 and the STAs 113 and 114, the AP 102 can set one or more Broadcast TWTs.

[0045] (TWT Information Acquisition Process in OBSS) This section describes an example of operation when AP102 sets TWT on network 122, and an example of operation when AP101 acquires information about TWT set on network 122 from AP102. The operation of AP102 setting TWT on network 122 corresponds to F603 to F606 in Figure 6. The operation of AP101 acquiring information about TWT set on network 122 from AP102 corresponds to F607 in Figure 6. AP102 can set TWT using a frame containing a TWT element. A TWT element is one of the Information Elements (information elements) communicated between 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., as shown in Figure 6. A TWT Request frame may be a TWT Setup frame with the value of the TWT Request field set to 1. Similarly, 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. A TWT element may also 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 an AP and an STA. Frames used when establishing a connection between the AP and STA include, for example, Probe Request frames, Probe Response frames, Association Request frames, and Association Response frames. In this case, AP102 can set TWT with STA113 and STA114 at the same time as establishing the connection.

[0046] 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 8A and 8B. 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.

[0047] Figure 8A 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 can 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 can also indicate whether the information contained in the TWT element is for the negotiation of Wake TBTT interval parameters. The MSB (Most Significant Bit) of the Negotiation Type subfield 803 may be called the Broadcast field. The information indicated by the Target Wake Time field 902, described later, differs depending on the value of the Negotiation Type subfield 804. The information shown by the TWT Wake Interval Mantissa field 905 and the TWT Wake Interval Exponent field 917, described later, differs depending on the value of the Negotiation Type subfield 804. Figure 8B is an example of the information shown by the Target Wake Time field 902 according to the value of the Negotiation Type subfield 803.FIG. 8B also includes an example of information indicated by a TWT Wake Interval Mantissa field 905 and a TWT Wake Interval Exponent field 917. Here, if the respective values of a Target Wake Time field 902 and the TWT Wake Interval Mantissa field 905 are 0, it can be shown that the TWT SP is not periodic. That is, if at least one of the values of the Target Wake Time field 902 or the TWT Wake Interval Mantissa field 905 is other than 0, it can be shown that the TWT SP is periodic.

[0048] The TWT Information Frame Disabled subfield 804 is set to a value of 1 when reception of a TWT Information frame is not possible. The Wake Duration Unit subfield 805 indicates the unit of information indicated by a Nominal Minimum TWT Wake Duration subfield 904 described later. For example, when the value of the Wake Duration Unit subfield 805 is 0, the unit is 256 μs, and when the value of the Wake Duration Unit subfield 805 is 1, it is shown that the unit is 1 TU. 1 TU (Time Unit) is 1024 μs. The Reserved subfield 806 is a reserved area.

[0049] 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 Individual TWT Parameter Set fields. The Individual TWT Parameter Set field includes the Request Type subfield 901, the Target Wake Time subfield 902, and the TWT Group Assist subfield 903. The Individual TWT Parameter Set field also includes the Nominal Minimum TWT Wake Duration subfield 904, the TWT Wake Interval Mantissa subfield 905, and the Individual TWT Parameter Set field also includes 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, 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.

[0050] 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, when an STA requests the setting of a TWT, the TWT Request subfield 911 is set to a value of 1. Alternatively, the TWT Request subfield 911 can 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, when an AP responds to a TWT setting request from an STA, the TWT Request subfield 911 is set to a value of 0. In the case of Broadcast TWT, if the communication device 100 transmitting the TWT element is the STA on the side where the TWT is scheduled (TWT scheduled STA), the value of 1 is set in the TWT Request subfield 911. If the communication device 100 transmitting the TWT element is the STA on the side where the TWT is scheduled (TWT scheduling STA), the value of 0 is set in the TWT Request subfield 911.

[0051] 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 a Request TWT. For example, a 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 a Suggest TWT. For example, a Suggest TWT indicates joining the TWT by specifying the corresponding values ​​from the proposed TWT parameters. The TWT parameters include the values ​​set in the Normal Minimum TWT Wake Duration subfield 904, the TWT Channel subfield 906, and the Trigger subfield 913, respectively. The TWT parameters also 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 STA on the TWT requesting side, indicates that the TWT command is a TWT Demand. For example, a TWT Demand indicates that the TWT will participate in the TWT by specifying the requested TWT parameters. The TWT Setup Command subfield 912, when set to a value of 3 by the STA on the responding side of the TWT, indicates that the TWT command is TWT Grouping. For example, TWT Grouping indicates that it proposes TWT group parameters different from those specified or requested by the STA on the requesting side of the TWT. The TWT Setup Command subfield 912, when set to a value of 4 by the STA on the responding side of the TWT, indicates that the TWT command is Accept TWT. For example, Accept TWT indicates that it accepts a TWT with TWT parameters specified by the other party's STA.The TWT Setup Command subfield 912, when set to a value of 5 by the STA on the responding side of the TWT, indicates that the TWT command is Alternate TWT. For example, Alternate TWT indicates that it proposes TWT parameters to replace the TWT parameters specified by the other party's STA. The TWT Setup Command subfield 912, when set to a value of 6 by the STA on the responding side of the TWT, indicates that the TWT command is Dictate TWT. For example, Dictate TWT indicates that it proposes TWT parameters to replace the TWT parameters specified by the other party's STA. The TWT Setup Command subfield 912, when set to a value of 7 by the STA on the responding side of the TWT, indicates that the TWT command is Reject TWT. For example, Reject TWT indicates rejection of TWT Setup. Reject TWT can also indicate termination of an existing broadcast TWT or termination of membership in a broadcast TWT. In the case of a Broadcast TWT, the STA on the requesting side of the TWT is the STA on the side where the TWT is scheduled, and the STA on the responding side of the TWT may be the STA on the side that schedules the TWT.

[0052] The Trigger subfield 913 indicates that a frame containing a Trigger frame or TRS is transmitted within the TWT SP. TRS is an abbreviation for Triggered Response Scheduling. A TWT in which a frame containing a Trigger frame or TRS is transmitted 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 Pagening Indicator subfield 801 may be set to 0. The Flow Type subfield 915 and the TWT Flow Identifier subfield 916 provide information about the operation when the power saving mode is executed. The TWT Wake Interval Exponent subfield 917, together with the TWT Wake Interval Mantissa subfield 905, indicates the TWT Wake Interval, as shown in Figure 8B. The TWT Wake Interval is the interval between TWT SPs. The TWT wake Interval can be expressed as an exponent with base 2, mantissa value of TWT Wake Interval Mantissa field 905, and exponent value of TWT Wake Interval Exponent subfield 917. The unit of TWT Wake Interval is μs. The TWT Protection subfield 918 is used by the TWT requesting STA to request frame protection by NAV.

[0053] The Target Wake Time subfield 902 displays different information depending on the value of the Negotiation Type subfield 803, as described above in Figure 8B. 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 indicated by 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, together with the TWT Wake Interval Exponent subfield 917 as described above, indicates the TWT Wake Interval. The TWT Channel 906 indicates the channel that the STA requesting the TWT requests to be used as the primary channel temporarily during the TWT SP. The NDP Paging subfield 907 is an optional region.

[0054] Figure 10 shows an example of the configuration of the 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 Normal 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 assigned 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. Among the subfields included in the Request Type subfield 1001, those also included in the Request Type subfield 901 are assigned the same reference number and the explanation is omitted.

[0055] The Last Broadcast Parameter Set subfield 1003 is valued at 0 if there are subsequent Broadcast TWT Parameter Set fields. That is, it is valued at 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 indicates information about the frames transmitted 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 transmitted within the TWT SP. When the Broadcast TWT Recommendation subfield 1004 is set to a value of 1, feedback for PS-Pol, QoS Null, QoS Control, and HE TB feedback NDP is recommended. Additionally, 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 value of 1 is set in the Broadcast TWT Recommendation subfield 1004, Action frames or Action No Ack frames from the Management frame are recommended. If the value of 1 is set in the Broadcast TWT Recommendation subfield 1004, Control response frames and Trigger frames for random access are recommended. If the value of 2 is set in the Broadcast TWT Recommendation subfield 1004, in addition to the above frames, (Re)Association Request frames are recommended.When the Broadcast TWT Recommendation subfield 1004 is set to a value of 3, it indicates that there are no restrictions on the frames to be transmitted, except in the case of TIM or FILS frames. TIM is an abbreviation for Traffic Indication Map. FILS is an abbreviation for Fast Initial Link Setup. Values ​​4 to 7 in the Broadcast TWT Recommendation subfield 1004 indicate Reserved.

[0056] The 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. In the IEEE 802.11be standard, Broadcast TWT frames are used in R-TWT, which is used for low-latency traffic communication.

[0057] AP102 uses the frame containing the TWT element described above to determine the TWT parameters of the TWT to be set with STA113 and STA114. For example, AP102 can determine the TWT parameters of individual TWTs with 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 the TWT SP with STA113 and STA114. AP102 can determine the interval between TWT SPs with STA113 and STA114 using the TWT Wake Interval Exponent subfield 917 and the TWT Wake Interval Mantissa subfield 905. AP102 can also determine with STA113 and STA114 whether or not to transmit a Trigger frame or a frame containing TRS within a TWT SP using the Trigger subfield 913. Furthermore, AP102 can set the TWT SPs to be used for one or more STAs included in the BSS using a TWT element that includes the Broadcast TWT Parameter Set field. In this case, AP102 may notify the TWT parameters to be used for Broadcast TWT using a Beacon frame that includes a Broadcast TWT Parameter Set field. Note that the information elements that AP102 uses to set TWT are not limited to TWT elements. For example, AP102 may use information elements other than TWT elements to determine the duration of TWT SPs, the interval between TWT SPs, etc., with the STA connected to its BSS and set TWT.

[0058] When AP102 sets a TWT, it notifies AP101 of information related to the set TWT. For example, AP102 may notify AP101 of information specifying the identification information of each set TWT, the number of STAs participating in each TWT, the period during 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. Note that when AP102 notifies AP101 of information related to 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 coordination 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 a TWT element containing the configured TWT parameters. For example, AP102 may send to AP101 a frame that includes the Target Wake Time subfield 902, the Normal Minimum TWT Wake Duration subfield 904, etc. Also, AP102 may send to AP101 a frame that includes the TWT Wake Interval Exponent subfield 917 and the TWT Wake Interval Mantissa subfield 905.

[0059] (Decision-making process for executing SP-based NPCA) The process by which AP101 determines whether or not to execute SP-based NPCA will be described. This process corresponds to F608 in Figure 6. When AP101 obtains information about TWT from another AP (for example, AP102), it determines whether or not to execute 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 execute 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 11A to 11C show examples of operation when making a determination by comparing the duration of the TWT SP with a predetermined threshold. In each of Figures 11A to 11C, the horizontal axis shows the passage of time. For example, in each TWT SP start time 1101 shown in Figure 11A, TWT SP 1103 begins. TWT SP 1103 continues for the duration of TWT SP. TWT SP 1103 is periodically set based on the interval between TWT SP 1103, indicated by Interval 1102. For example, TWT SP start time 1101 may correspond to a value indicated by the Target Wake Time subfield 902. Interval 1102 may correspond to 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 shown in the Nominal Minimum TWT Wake Duration subfield 904. In Figures 11A-C, Interval 1102 shows the time interval between TWT SP start times 1101, but a different time interval may be shown. For example, Interval 1102 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 Internal Exponent subfield 917 and the TWT Wake Internal Mantissa subfield 905 may also be set in this way. Figures 11A to C show different durations for TWT SPs 1103, 1106, and 1107. The first threshold 1104 and the second threshold 1105, shown in each of Figures 11A 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 durations 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.

[0060] In Figure 11A, the duration of TWT SP 1102 is less than both the first threshold 1104 and the second threshold 1105. In this case, AP 101 may determine that SP-based NPCA should not be performed. When AP 101 or STA 110 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 AP 101 may determine not to perform SP-based NPCA in the case of Figure 11A. In Figure 11B, the duration of TWT SP 1106 is greater than the first threshold and less than the second threshold. In this case, AP 101 may determine that SP-based NPCA should be performed. In Figure 11C, the duration of TWT SP 1107 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 the OBSS is long, the amount of traffic transmitted on that TWT SP is large, and the PCH may become congested even outside the TWT SP period. Therefore, if that PCH continues to be used, the overall throughput of the network 121 is likely to decrease. For this reason, AP101 may determine that the PCH should be changed in the case of Figure 11C. If the PCH is changed, AP101 notifies information that allows its BSS 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.

[0061] 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 may use the EMLSR Transition delay obtained from STA110 as the switching time for STA110 to switch from the first communication method to the second communication method, and set the first threshold 1104. AP101 may also 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.

[0062] 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.

[0063] 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. This single TWT information 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 TWT SPs, the duration of TWT SPs, 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 section. Figure 12 also shows the TWT SP start time 1221, Interval 1222, and TWT SP 1223 of the second TWT in the middle section. Finally, Figure 12 shows the TWT SP start time, Interval, and TWT SP of the integrated TWT based on integrated OBSS TWT information, which is obtained by integrating the information of the first and second TWTs, in the lower section. 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 may determine whether or not to perform an SP-based NPCA based on the integrated OBSS TWT information. For example, AP101 may determine that an SP-based NPCA should not be performed if the maximum duration of TWT SP1213 and TWT SP1223 included in the integrated TWT is less than a first threshold. Also, 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 a first threshold and less than a 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.

[0064] AP101 may generate integrated OBSS TWT information based on a portion of the TWT information obtained from AP102. For example, AP101 can generate integrated OBSS TWT information using TWT information that satisfies predetermined conditions. As an example, AP101 can generate integrated OBSS TWT information using information of TWTs in which the TWT SP included in the TWT is periodic, and not using information of TWTs in which the TWT SP included in the TWT is not periodic. By using only TWTs in which the TWT SP is periodic, the process of generating integrated OBSS TWT information can be simplified. Also, AP101 can generate integrated OBSS TWT information using information of TWTs in which the number of STAs participating in the TWT is greater than or equal to a predetermined number, and not using information of TWTs in which the number of STAs participating in the TWT is less than a predetermined number. If the number of participating STAs is small, there is a high probability that the traffic at the TWT SP for that TWT is small. Therefore, even if a TWT is configured in the OBSS, it may be more efficient to communicate using the first communication method. The number of STAs participating in a TWT may be an absolute number, or it may be a ratio of the number of STAs participating in the TWT to the number of STAs in the BSS. The ratio of the number of STAs participating in the 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 that the configured TWT is a Broadcast TWT and use this to generate integrated OBSS TWT information. For example, AP101 may determine that a Broadcast TWT has more participating STAs than an individual TWT. The conditions for AP101 to select the TWTs to use in generating integrated OBSS TWT information are not limited to these. For example, AP101 may use TWT information where the duration of the TWT SP is greater than the first threshold. This allows for the exclusion of periods that are too short to be used as NPCA SPs from the integrated TWT. Based on the integrated OBSS TWT information generated in this way, using 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 TWT information to be used in generating 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.

[0065] Furthermore, AP101 may combine some of the TWT SPs included in the integrated TWT. Figure 13 shows another example of a method for generating integrated OBSS TWT information. In Figure 13, the lower integrated TWT shows an extended TWT SP1331 generated by combining the TWT SP1313 of the first TWT and the 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. As a result, even if the duration length of one or both TWT SPs is shorter than the first threshold, communication using NPCA can be performed based on the fact that the duration length of the extended TWT SP is longer than the first threshold.

[0066] In the above explanation, an example was used to describe how to generate one integrated OBSS TWT information based on information from two TWTs. However, 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 integrated TWT information. 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. Before generating integrated OBSS TWT information, AP101 can determine whether each TWT satisfies the conditions for selecting TWTs to be used in generating the integrated TWT information described above, and generate integrated TWT information using only the TWT information that satisfies the conditions.

[0067] (Notification of SP-based NPCA execution) The operation of AP101 when notifying STA110 to start communication using SP-based NPCA will be described. 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 start communication using SP-based NPCA. For example, AP101 may notify STA110 connected to its device that it will start 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.

[0068] Furthermore, AP101 may notify STA110 or its own BSS of the period during which communication using SP-based NPCA will be 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 a TWT SP shorter than a first threshold, AP101 may exclude that TWT SP and determine the NPCA SP. Furthermore, 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 a period corresponding to the extended TWT SP formed by combining those TWT SPs.

[0069] 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 for identifying the determined NPCA SP. This information element may include subfields included in the TWT element. As an example, this information element may include the Target Wake Time subfield 902, the Nominal Minimum TWT Wake Duration subfield 904, etc. Furthermore, this information element may include the TWT Wake Interval Exponent subfield 917 and the TWT Wake Interval Mantissa subfield 905. AP101 may include information elements indicating TWT information contained in frames received from other APs as information elements indicating NPCA SPs in a frame for notifying NPCA information. For example, AP101 may include at least a portion of TWT elements containing information on individual TWTs and Broadcast TWTs obtained from AP102 as information in a frame for notifying NPCA information. In this case, AP101 may include information contained in TWT elements corresponding to the information of one or more TWTs used to generate the integrated OBSS TWT information in a single frame for notifying NPCA information as information for identifying NPCA SPs.

[0070] 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 an NPCA SP by using an offset value notified by AP101 for a predetermined NPCA SP.

[0071] Furthermore, AP101 may be configured so that both AP101 and STA110 can determine whether or not to perform communication using SP-based NPCA. In this case, AP101 can notify STA110 of information regarding TWT 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 information regarding TWT obtained from other APs may include information such as the TWT SP start time, TWT Wake Interval, the duration of the TWT SP, and whether or not a Trigger frame is included in the TWT SP. Furthermore, if AP101 acquires information on two or more TWTs, it may notify STA110 of the information on each TWT, and may also notify STA110 of the integrated OBSS TWT information generated based on this TWT information. When AP101 and STA110 each decide whether or not to use SP-based NPCA communication, AP101 and STA110 each set an NPCA SP based on the determination result of their respective devices. In addition, AP101 and STA110 each perform a switch from the first communication method to the second communication method at the set NPCA SP. Furthermore, AP101 may use the frame for notifying the above-mentioned NPCA information to notify STA110 of the TWT information acquired from AP102 and the information necessary for STA110 to decide whether or not to use SP-based NPCA communication. Furthermore, AP101 may notify STA110 of the information necessary for STA110 to determine whether or not to perform communication using SP-based NPCA, using a frame used for NPCA negotiation. In this case, AP101 may notify information about TWT obtained from other APs using a frame for notifying information about NPCA.

[0072] (Execution of SP-based NPCA) The processes of AP101 and STA110 when performing communication using SP-based NPCA will be described below. This operation corresponds to F610 to F618 in Figure 6. Figure 14 shows an example of a processing flow executed by AP101. This processing flow may be executed based on the fact that AP101 has established 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 communication using NPCA at all with STA110. AP101 may also decide to perform both communication using SP-based NPCA and communication using TXOP-based NPCA.

[0073] If, through NPCA negotiation, it is decided to perform communication using SP-based NPCA (YES in S1402), AP101 collects TWT information from OBSS (S1403). For example, AP101 may perform a procedure for multi-AP coordination with AP102 and obtain TWT information set in network 122 from AP102. Alternatively, AP101 may collect TWT information from OBSS from frames received from OBSS, as will be described later (S1404). Based on the collected TWT information from OBSS, 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, AP101 determines that communication using SP-based NPCA should not be performed if the duration of the TWT SP is less than the first threshold. AP101 determines that the PCH should be changed if the duration of the TWT SP is greater than the second threshold. AP101 determines that communication using SP-based NPCA should be performed if the duration of the TWT SP is greater than the first threshold and less than the second threshold. 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 initiates communication using NPCA and transmits information to STA110 to identify the NPCA SP (S1407).For example, AP101 may notify STA110 of the generated integrated OBSS TWT information as information for identifying 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 by NPCA (S1408).

[0074] 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 of whether or not communication using SP-based NPCA should be performed. For example, AP101 may increase the threshold for the number of STAs participating in a 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 a 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). Furthermore, if AP101 does not change the TWT information used to generate the integrated OBSS TWT information (NO in S1411), it determines that communication by NPCA should not be performed (S1412). In this case, AP101 maintains communication using the first communication method. Note that if AP101 determines that communication by NPCA should not be performed, it may notify STA110 that it will not perform communication by NPCA.

[0075] On the other hand, if the NPCA negotiation determines that TXOP-based NPCA should be performed (NO in S1402 and YES in S1409), AP101 performs communication using TXOP-based NPCA (S1410). For example, AP101 monitors the state of the PCH. When AP101 detects a signal in 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.

[0076] If AP101 decides not to perform communication by NPCA during NPCA negotiation with STA110 (NO in S1402 and NO in S1409), it will not perform communication by NPCA and will maintain communication by the first communication method (S1412).

[0077] Next, the operation of AP101 when performing SP-based NPCA communication (S1408) will be explained using Figure 15. When the timing for NPCA SP to start occurs (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 the OBSS before switching to the second communication method. For example, if the TWT information obtained from another AP indicates that it is a trigger-enabled TWT, AP101 may decide that it should detect a Trigger frame. 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 the 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.

[0078] 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 TWT information of the OBSS 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. Furthermore, AP101 may periodically recollect TWT information from OBSS and change the NPCA SP based on the updated TWT information from OBSS. Also, if AP101 obtains new TWT information from another AP, it may change the NPCA SP based on the updated TWT information from OBSS. If AP101 recollects TWT information from OBSS (YES in S1508), it proceeds to S1403 and continues processing. If AP101 does not recollect TWT information from OBSS (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.

[0079] 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 an 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.

[0080] If, through NPCA negotiation, it is decided to perform SP-based NPCA (YES in S1602), STA110 performs communication using SP-based NPCA based on the notification from AP101. STA110 may also collect OBSS TWT information based on instructions from AP101 (YES in S1603) (S1604). In this case, STA110 reports the collected OBSS TWT information to AP (S1604). When STA110 receives information from AP101 to identify an NPCA SP (YES in S1605), it performs 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 can receive TWT information obtained by AP101 from other APs, and information necessary for STA110 to determine whether or not to perform communication using SP-based NPCA. In this case, STA110 will determine whether or not to perform communication using NPCA based on this information. For example, STA110 can generate integrated OBSS TWT information in its own device and determine whether or not to perform communication using NPCA by determining whether or not the TWT SP included in the integrated OBSS TWT information satisfies the conditions received from AP101. STA110 can also identify NPCA SPs based on the generated integrated OBSS TWT information. When it is time for an NPCA SP, 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 will not perform communication using NPCA and will maintain communication using the first communication method (S1609).

[0081] If the NPCA negotiation determines that a TXOP-based NPCA should be performed (NO in S1602 and YES in S1607), STA110 performs communication using a TXOP-based NPCA (S1608). If the NPCA negotiation determines that a TXOP-based NPCA should not be performed (NO in S1602 and NO in S1607), STA110 maintains communication using the first communication method without performing communication using a TXOP-based NPCA (S1609).

[0082] The operation of STA110 when performing SP-based NPCA communication (S1606) will be explained with reference to Figure 17. In Figure 17, the same reference numbers are used for processes similar to those in Figure 15, and the explanation is omitted. That is, STA110 operates in the NPCA SP in the same way as AP101 and communicates data with AP101 (S1501 to S1504). When it is time for STA110 to terminate the NPCA SP (YES in S1505), and after switching to communication using the first communication method (S1506), STA110 may receive a notification from AP101 indicating the termination 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.

[0083] (Modified Example) The above example described how AP101 obtains TWT information of OBSS from AP102. In this modified example, we will describe an example in which AP101 collects TWT information set in OBSS (network 123) configured by AP103 in Figure 1. As described 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 TWT information of OBSS collected in this way, AP101 can determine whether or not to perform communication using SP-based NPCA.

[0084] Figure 18 shows an example sequence when AP101 performs communication using SP-based NPCA based on TWT information set in network 123. In Figure 18, the same reference numbers are used for configurations similar to those in Figure 6, 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 can receive TWT Setup frames (TWT Request frames, TWT Response frames) and Beacon frames transmitted in network 123. 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 of the communication devices participating in network 123 may not be received by some of the communication devices participating in network 121. For example, in the configuration of 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 has received 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 has received 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 a frame for exchanging OBSS TWT information.The frame for exchanging OBSS TWT information may be a new type of Action frame as defined in the IEEE 802.11 standard series.

[0085] In network 123 in Figure 18, a Trigger frame is transmitted from AP 123 within the configured TWT SP period (F1803). Upon receiving the Trigger frame, STA 115 responds with a PS-Pol frame (F1804). Upon receiving the Trigger frame, STA 116 responds with a QoS Null frame (F1805). AP 101 transmits data frames to STA 115 and STA 116 based on the received PS-Pol and QoS Null frames (F1806). STA 115 and STA 116 each provide acknowledgments for the data frames they received (F1807). Acknowledgments may be made using BlockACK frames. On the other hand, AP101 and STA110 switch from communication using the first communication method to communication using the second communication method based on the reception of a Trigger frame transmitted on network 123 during the NPCA SP period (F610). If AP101 and STA110 do not receive a Trigger frame transmitted on network 123 during the NPCA SP period, they maintain communication using the first communication method. 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 at 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.

[0086] 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 performed when predetermined conditions are met. The predetermined condition is 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 may notify STA110 that it should switch from the first communication method to the second communication method based on the receipt of a Trigger frame. Thus, the operation in which AP101 and STA110 switch to the second communication method upon detecting the transmission of a Trigger frame in OBSS can be described as the operation of initiating NPCA using the Control frame of the IEEE 802.11 standard. With this configuration, the period in which AP101 and STA110 maintain communication using the first communication method is extended, which can improve the efficiency of frequency resource utilization.

[0087] 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 the OBSS. The communication device 100 also determines whether or not to perform communication using SP-based NPCA based on the duration of the TWT SP set in the 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 local BSS and the OBSS.

[0088] In this embodiment, the communication method that does not use 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 NPCH is exemplified as SPCH for convenience, but it is not limited to this. Among multiple NPCHs, it may be called PSCH (Primary Secondary Channel) to mean the channel with the highest priority for determining whether or not to transmit. In any case, it means that it is the channel that should be used to determine whether or not to transmit using NPCH. Also, the configurations of frames, information elements, fields, subfields, etc. described in this embodiment are illustrative and may be called by different names. Also, some information may not be included in each configuration, or other information may be included. Integrated TWT and Extended TWT SP may be called by other names.

[0089] 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 (for example, an ASIC) that implements one or more functions.

[0090] (Other Embodiments) The present disclosure can also be realized by supplying a program that implements one or more of the functions of the embodiments described above to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more functions.

[0091] The technical ideas derived from this disclosure are not limited to the exemplary embodiments disclosed, but are intended to encompass various modifications of the exemplary embodiments, or substitutions with equivalent structures or functions. The scope of the following claims should be interpreted in the broadest way to encompass all such modifications and equivalent structures and functions.

[0092] This application claims priority based on Japanese Patent Application No. 2024-185216, filed on October 21, 2024, and all of its contents are incorporated herein by reference.

Claims

1. A communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, comprising: 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 communication means for performing communication using a plurality of communication methods; and acquisition means for 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; and the TWT set in the OBSS A communication device comprising: 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 SP; and 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.

2. The communication device according to claim 1, further comprising a means for specifying the period during which communication using the second communication method is performed.

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

4. The communication device according to any one of claims 1 to 3, wherein the acquisition means acquires information regarding TWT SP set in the OBSS from access points constituting the OBSS.

5. The communication device according to any one of claims 1 to 4, wherein the acquisition means acquires information relating to the TWT SP set in the OBSS by the communication device or the other communication device receiving a wireless frame transmitted in the OBSS.

6. The communication device according to any one of claims 1 to 5, wherein the determination means determines that communication using the second communication method will be performed during the period in which the TWT SP is set, based on the fact that the period length of the TWT SP set in the OBSS is longer than a predetermined value.

7. The communication device according to any one of claims 1 to 6, wherein the determination means determines that communication using the second communication method will be performed during the period in which the TWT SP is set, based on the fact that the sum of the period lengths of the TWT SP set in the OBSS over a certain period is longer than a predetermined value.

8. The communication device according to any one of claims 1 to 7, wherein the determination means performs the determination based on the period length of the TWT SPs that are set periodically among the TWT SPs set in the OBSS.

9. The communication device according to any one of claims 1 to 8, wherein the determination means performs the determination based on the duration of a TWT SP in which more than a predetermined number of terminal devices participate, among the TWT SPs set in the OBSS.

10. The communication device according to claim 1, wherein, 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.

11. The communication device according to claim 2 or 3, wherein the notification means provides a notification that, upon the commencement of the specified period, a switch should be made from communication using the first communication method to communication using the second communication method.

12. The communication device according to claim 2 or 3, wherein the notification means provides a notification that, upon receiving a Trigger frame transmitted in the OBSS within the specified period, the device should switch from communication using the first communication method to communication using the second communication method.

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, comprising: 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 performs communication using a plurality of communication methods, and 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, and the TWT set in the OBSS A control method comprising: 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 SP; and notifying the other communication device that communication using the second communication method will be performed based on the result of the determination.

14. A program for causing a computer to function as each of the means of the communication device described in any one of claims 1 to 12.

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