Communication apparatus, communication method, and storage medium

Abstract

To improve utilization efficiency of a channel in a communication system using a communication link composed of a plurality of channels.SOLUTION: Forming a first channel and one or more second channels different from the first channel by channel bonding in conformity with a predetermined standard included in a IEEE802. 11 standard series; By using a wireless frame conforming to the predetermined standard, the wireless frame including a first communication scheme in which communication is performed by acquiring a transmission right by using a first channel and a second communication scheme in which communication is performed by acquiring a transmission right by using a third channel included in a second channel in a case where the first channel is not able to be used, A communication device that communicates with another communication device specifies a predetermined frequency bandwidth used by the communication device for communication, and notifies the other communication device that communication using a second communication method is disabled on the basis of the fact that the predetermined frequency bandwidth is a predetermined value.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a communication control technique in a communication device capable of communicating using a communication link configured to include one or more channels of a predetermined frequency bandwidth. [Background technology]

[0002] In recent years, the increasing volume of data being transmitted has led to the development of communication technologies such as wireless local area networks (WLANs). The IEEE (Institute of Electrical and Electronic Engineers) 802.11 standard series is known as the main WLAN communication standard. The IEEE 802.11 standard series includes IEEE 802.11a / b / g / n / ac / ax / be standards. To further improve communication reliability, the IEEE 802.11bn standard is currently being developed as the successor to the IEEE 802.11be standard. The IEEE 802.11 Working Group (WG), which is developing the IEEE 802.11bn standard, is defining the goals and scope of the standard in the UHR SG, and the TGbn will specify the detailed technical content to be included in the standard. UHR SG stands for Ultra High Reliability Study Group. TGbn is also an abbreviation for Task Group bn.

[0003] As one of the candidates for the technology to be included in the IEEE802.11bn standard, a technology for efficiently utilizing frequency resources in a communication method using a communication link configured including one or more channels of a predetermined frequency bandwidth is being considered. For example, Patent Document 1 describes a technology for performing communication without using the primary channel by acquiring the transmission right using another channel when the primary channel used to acquire the transmission right is unavailable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 1,1696,353 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a technique for efficiently utilizing frequency resources in a communication system that uses a communication link that includes one or more channels of a predetermined frequency bandwidth. [Means for solving the problem]

[0006] A communication device according to one embodiment of the present invention is a communication device capable of communicating with other communication devices using wireless frames that comply with at least one predetermined standard included in the IEEE 802.11 standard series, wherein the predetermined standard includes provisions for communicating using multiple communication methods, including: 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 acquiring a transmission right using the first channel and communicating; and a second communication method acquiring a transmission right using a third channel included in the second channels when the first channel cannot be used and communicating using at least the third channel, and the communication device has an identification means for identifying a predetermined frequency bandwidth that the communication device is configured to use for communication, and a notification means for notifying the other communication device that communication using the second communication method will be disabled based on the predetermined frequency bandwidth being a predetermined value. [Effects of the Invention]

[0007] According to the present invention, it is possible to efficiently utilize frequency resources in a communication system that uses a communication link that includes one or more channels of a predetermined frequency bandwidth. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Figure 2] FIG. 2 is a schematic diagram illustrating an example of a time chart when a communication device transmits data. [Figure 3] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Figure 4] FIG. 2 illustrates an example of a functional configuration of a communication device. [Figure 5] FIG. 10 is a diagram illustrating an example of a flow when a communication device disables the use of a second communication method. [Figure 6] FIG. 10 is a diagram illustrating an example of a flow when a communication device communicates data. [Figure 7] FIG. 10 is a diagram illustrating an example of a flow when a communication device disables the use of a second communication method. [Figure 8] 10 is an example of a sequence executed between communication devices. [Figure 9] FIG. 10 is a diagram illustrating an example of the configuration of a UHR Capabilities element. [Figure 10] FIG. 10 is a diagram illustrating an example of the configuration of an NPCH Operating Mode Notification frame Action field. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] (System Configuration) FIG. 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 a station (STA) 102. The AP 101 and the STA 102 are each communication devices capable of performing wireless communication in accordance with the IEEE 802.11 standard series. In this embodiment, the AP 101 and the STA 102 may be collectively referred to as a communication device 100. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. FIG. 1 shows a configuration in which the STA 102 participates in a network 103 established by the AP 101. The network 103 may also be referred to as a Basic Service Set (BSS). Note that FIG. 1 also shows a state in which a network 113 established by an AP 111 and in which a STA 112 participates exists near the network 103 established by the AP 101 and in which the STA 102 participates. The AP 111 and the STA 112 are communication devices capable of performing wireless communication in accordance with the IEEE 802.11 standard series, just like the AP 101 and the STA 102. For AP 101 and STA 102, network 103 is the BSS to which they connect, and hereinafter this BSS will be referred to as their own BSS or simply as their BSS. On the other hand, for AP 101 and STA 102, network 113 is a network that may cause interference to their own BSS, and may be called an overlapping BSS (OBSS). Note that while FIG. 1 shows a state in which one STA participates in each of network 103 and network 113, it goes without saying that multiple STAs may participate in one network. Furthermore, one STA may participate in multiple networks.

[0011] In this embodiment, the AP 101 and the STA 102 are configured to be able to execute a communication method compliant with the IEEE 802.11bn standard. The IEEE 802.11bn standard is a successor to the IEEE 802.11be standard, which targets a maximum transmission speed of 46.08 Gbps (Giga bit per second). The IEEE 802.11bn standard is expected to specify, as its main features, functions that realize highly reliable communication, low latency communication, and improved throughput when communication traffic is congested. A wireless frame used in a communication method compliant with this standard may be called an UHR (Ultra High Reliability) PPDU. PPDU stands for PLCP Protocol Data Unit, and PLCP stands for Physical Layer Convergence Protocol. Note that the names UHR, IEEE 802.11bn, etc. may be changed to different names when the standard is fully established. It should be noted that this specification and the claims appended hereto are applicable to communication devices using all successor standards to IEEE 802.11be. The communication device 100 may support at least one legacy standard that predates the IEEE 802.11bn standard. Examples of legacy standards include the IEEE 802.11a / b / g / n / ac / ax / be standards. The communication device 100 may also support other communication standards, such as Bluetooth (registered trademark), NFC, UWB, ZigBee, and MBOA. UWB stands for Ultra Wide Band, and MBOA stands for Multi-Band OFDM Alliance. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, and the like. The communication device 100 may also support communication standards such as wired LAN. The AP 101 is, for example, but not limited to, a wireless LAN router, a personal computer (PC), etc. The AP 101 may be an information processing device such as a wireless chip capable of performing wireless communication in accordance with the IEEE802.11bn standard or the like.The STA 102 may be, for example, but is not limited to, a camera, a tablet, a smartphone, a PC, a mobile phone, a video camera, a headset, etc. The STA 102 may be an information processing device such as a wireless chip capable of performing wireless communication in accordance with the IEEE802.11bn standard or the like.

[0012] The communication device 100 may transmit and receive radio signals using frequency bands such as the 2.4 GHz band, 3.6 GHz band, 5 GHz band, and 6 GHz band, as well as millimeter wave bands such as the 45 GHz band and the 60 GHz band. The frequency bands used by the communication device 100 are not limited to these and may include, for example, the sub-1 GHz band. The communication device 100 may also communicate using frequency bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The frequency bandwidths used by the communication device 100 are not limited to these and may include, for example, frequency bandwidths of 240 MHz, 4 MHz, and the like. The IEEE 802.11 standard series specifies a frequency channel using a frequency bandwidth of 20 MHz as the basic channel in frequency bands such as the 2.4 GHz, 5 GHz, and 6 GHz bands. This standard also defines multiple channels available for communication in each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. This standard allows communication device 100 to use a channel in combination with an adjacent channel. This use of a channel in combination with an adjacent channel may be referred to as channel bonding. For example, channel bonding may combine a first channel with a 20 MHz frequency bandwidth and a second channel with a 20 MHz frequency bandwidth adjacent to the first channel to form a single 40 MHz channel. In this way, a link formed as a physical path usable for transmitting data between communication devices is composed of one or two or more adjacent channels with a predetermined frequency bandwidth. In other words, data with a frequency bandwidth of 40 MHz can be transmitted over a single link formed by two adjacent channels with a 20 MHz frequency bandwidth. The IEEE 802.11be standard is expected to specify 320 MHz as the maximum frequency bandwidth available for a single link. The transmission signal may be continuous or discontinuous on the frequency axis within this frequency bandwidth. For example, some frequency bands within this frequency bandwidth may not be used for transmitting signals.The IEEE802.11be standard is expected to define Multi-Link communication, which uses multiple links established between a pair of communication devices for parallel communication. The AP 101 and the STA 102 may be an AP MLD (Multi-Link Device) and a STA MLD that support Multi-Link communication.

[0013] When transmitting a signal using a link established with another communication device, the communication device 100 performs carrier sensing to determine whether transmission is possible. Carrier sensing is an operation in which the communication device 100 determines whether a signal is present on a channel that the communication device 100 intends to use for transmission. For example, the communication device 100 measures the strength of a signal received on a channel (received signal strength) and determines that a signal is present when the received signal strength exceeds a predetermined threshold (physical carrier sensing). The received signal strength may also be referred to as a Received Signal Strength Indicator (RSSI). The communication device 100 may also determine the presence or absence of a signal based on information such as a Duration field included in the signal received on the channel (virtual carrier sensing). For example, the communication device 100 stores the period indicated by the Duration field included in the received signal as a Network Allocation Vector (NAV) within the communication device 100. The communication device 100 may treat the stored NAV as a period during which the communication device 100 prohibits transmission of wireless frames. In this embodiment, the operation of the communication device 100 to set a period during which the device will not transmit based on information such as the Duration field of a received signal is referred to as setting a NAV. That is, the communication device 100 determines that a signal is present on the channel until the NAV set for the channel expires. In this manner, the communication device 100 determines whether a signal is present on the channel based on the results of performing physical carrier sense and virtual carrier sense. If the communication device 100 determines that a signal is present on the channel, it may determine that the channel is in a state in which it cannot transmit a signal (transmission is not possible). The channel state in this case may be referred to as a busy state. On the other hand, if no signal is detected on the channel by carrier sense and no NAV is set, it may be referred to as an idle state. If the channel is in an idle state, the communication device 100 may determine that the channel is in a state in which it can transmit a signal (transmission possible).

[0014] For example, when communicating using a link with an available frequency band of 160 MHz, the communication device 100 may determine whether or not to transmit using only a first channel with a 20 MHz frequency band included in that frequency band. This first channel may be called a Primary Channel (PCH). For example, the IEEE 802.11 series of standards specifies that the communication device 100 can start transmitting signals if it determines that transmission is possible as a result of performing carrier sensing on the PCH for a predetermined period. The predetermined period is determined by an Interframe Space (IFS) defined for each access category that classifies the type of communication traffic and a random number (backoff counter) randomly determined from a predetermined range. That is, if the communication device 100 determines that the PCH is idle for this predetermined period, it acquires a transmission right to transmit using that PCH. At this time, if a second channel other than the PCH is idle during the PIFS period immediately before the start of transmission, the communication device 100 may perform channel bonding transmission using the idle channel and the PCH. PIFS is an abbreviation for Priority Interframe Space. On the other hand, when the communication device 100 determines that it cannot transmit a signal as a result of performing carrier sensing on the PCH, it postpones the transmission even if other channels included in the frequency band of the above-mentioned 160 MHz frequency bandwidth are idle. That is, in this case, the communication device 100 does not transmit a signal using only the other channels. Note that each channel other than the PCH in the frequency band available for use in one link may also be called a secondary channel (SCH) or a non-primary channel (NPCH).

[0015] When a communication device 100 receives a signal on a certain channel, if a signal is transmitted on another channel (e.g., an adjacent channel) that is located at a frequency close to the received channel, the received signal may not be properly received. For example, the communication device 100 may be capable of simultaneously performing transmission and reception processes using different channels. In this case, if the communication device 100 performs transmission processing on an adjacent channel while performing reception processing on a certain channel, the power of the transmission signal may leak into the channel of the received signal, causing interference with the received signal. Generally, the power of such leakage of the transmission signal is much greater than the received power of the received signal, making it impossible to properly receive and process the received signal. To avoid this situation, the IEEE 802.11 series of standards provides the above-mentioned mechanism to prevent other communication devices from transmitting signals to the communication device using a channel adjacent to the PCH while the communication device is transmitting a signal. That is, the PCH is provided as a channel commonly used between communication devices to determine whether or not to transmit, and it is specified that while one communication device is transmitting using the PCH, the other communication device shall not transmit even if the other channel is idle. As a result, while a communication device is transmitting a signal and the PCH is in use, other communication devices will not transmit signals using channels adjacent to the PCH, preventing the communication device from receiving signals on the adjacent channels. This eliminates the problem of interference caused by power leakage between channels.

[0016] However, not using other idle channels (NPCHs) based on the PCH being busy can hinder efficient use of frequency resources across the entire frequency band available for the link. Figure 2A shows an example of a time chart when STA 102 transmits data to AP 101. In Figure 2A, STA 102 performs carrier sensing on the PCH, confirms that the PCH is idle, and then transmits data using the PCH with a 20 MHz frequency bandwidth. In this case, even if, for example, seven NPCHs other than the PCH are idle, other communication devices are not permitted to communicate using the NPCHs. Figure 2B shows another example of a time chart when STA 102 transmits data to AP 101. Figure 2B shows an example in which the PCH is being used by another network (e.g., network 113 in Figure 1) located geographically close to STA 102 while STA 102 is performing carrier sensing on the PCH. In this case, the PCH is determined to be busy by the carrier sense of the STA 102, and therefore, even if the seven NPCHs other than the PCH are idle, the STA 102 is not permitted to communicate with the AP 101 using the NPCH. However, since the AP 101 is not transmitting at this time, if the STA 102 transmits to the AP 101 using the NPCH, it is expected that the AP 101 will be able to properly receive and process the signal transmitted by the STA 102. In this way, if the PCH with a frequency bandwidth of, for example, 20 MHz is being used by another network, and the remaining 140 MHz of idle NPCH is not used, frequency resources cannot be used efficiently.

[0017] On the other hand, if a function is provided to perform communication using an NPCH included in a frequency band available for the link used by the communication device 100 without using the PCH when the PCH is being used by another communication device, efficient use of frequency resources becomes possible. As an example, when the PCH is busy, the communication device 100 sets a Secondary Primary Channel (SPCH) to be used to acquire a transmission right for transmission using the NPCH. The SPCH is one or more channels among the NPCH included in a frequency band available for the link used by the communication device 100. If the communication device 100 determines that the PCH is being used by another communication device, it subsequently determines whether transmission is possible on the SPCH. For example, the communication device 100 may perform the above-described carrier sense on the SPCH and determine that communication using the NPCH is possible based on confirming that the SPCH is idle. Then, if the communication device 100 determines that communication using the NPCH is possible, it performs transmission using one or more NPCHs including the SPCH. With this configuration, even if the PCH is unavailable, communication using the NPCH becomes possible, enabling efficient use of frequency resources. For example, first, when a PCH is available, the communication device 100 performs communication using a first communication method in which communication is performed using a PCH and one or more NPCHs. In this case, the communication device 100 may perform communication using only the PCH. On the other hand, the communication device 100 is configured to perform communication using a second communication method in which communication is performed using an NPCH that satisfies the second condition without using a PCH, when a first condition is that the PCH is unavailable. The second condition may be, for example, that an NPCH is not being used. In this embodiment, a communication method in which transmission is performed using one or more NPCHs including an SPCH that has been confirmed to be in an idle state without using a PCH is called NPCH access (Non-Primary Channel Access). NPCH access is an example of the second communication method.

[0018] It should be noted that the name SPCH is merely an example, and other names may be used. For example, instead of the name SPCH, the name PSCH (Primary Secondary Channel) may be used as a channel with a high priority among multiple NPCHs that is used to determine whether transmission is possible. Furthermore, SPCH or PSCH may be called by other names as long as they indicate that it is a channel used to determine whether transmission using NPCH is possible. Similarly, NPCH access may also be called by other names. For example, NPCH access may be called NPCA (Non-Primary Channel Access), SCA (Secondary Channel Access), etc.

[0019] Here, even if the communication device 100 has the capability to communicate using both the first and second communication methods, there may be cases where it is unable to actually perform communication using the second communication method. For example, when the frequency bandwidth configured for communication in the communication device 100 is 20 MHz, the communication device 100 cannot perform NPCH access. That is, NPCH access can be used when communication is possible using a channel with a frequency bandwidth of 40 MHz or more formed by channel bonding of multiple 20 MHz frequency bandwidth channels included in the frequency bandwidth used in one link. Therefore, a communication device 100 capable of performing NPCH access has the capability to communicate using a channel with a frequency bandwidth of 40 MHz or more. In this case, a communication device capable of communicating using a channel with a frequency bandwidth of 40 MHz or more may be configured to operate at a frequency bandwidth of 20 MHz for purposes such as reducing channel congestion, avoiding interference with other communications, and reducing the power consumption of the device itself. When such a configuration is performed, the communication device 100 operates only using the PCH with a frequency bandwidth of 20 MHz, and therefore is unable to perform NPCH access.

[0020] In this case, even if the communication device 100 and the other communication device have mutually notified each other that they are capable of using a first communication method and a second communication method, there is a possibility that communication will not be efficient due to the difference in the communication methods actually used for communication. For example, if the communication device 100 notifies the other communication device that it is capable of performing NPCH access and the communication device 100 is configured to use a 20 MHz frequency bandwidth, the other communication device may transmit using NPCH access. In this case, the communication device 100 cannot receive data transmitted by the other communication device using NPCH access, resulting in reduced communication efficiency. As an example, the communication device 100 may notify the other communication device that it is capable of performing NPCH access when establishing a connection with the other communication device. Furthermore, the communication device 100 may notify the other communication device of the frequency bandwidth that it will use for communication when establishing a connection with the other communication device. However, these notifications may not necessarily be associated with each other and used to determine whether or not to perform NPCH access in the other communication device. For example, even if the communication device 100 notifies the other communication device that the frequency bandwidth available to it is 20 MHz, the other communication device may transmit data using the NPCH based on the fact that the SPCH is idle. In this case, the communication device 100 cannot receive this data. As a result, the other communication device may perform a retransmission process due to a transmission failure or disconnect the connection due to a period of time during which communication is unavailable. Also, when the frequency bandwidth available to the other communication device is 20 MHz, the communication device 100 may perform a data transmission using the NPCH based on the fact that the SPCH is idle. In this case, the communication device 100 may similarly perform a retransmission process due to a transmission failure or disconnect the connection due to a period of time during which communication is unavailable. Note that even if the communication device 100 and the other communication device can use a frequency bandwidth of 40 MHz or more when establishing a connection, the frequency bandwidth used during communication after the connection is established may change.In such a case, even if the changed frequency bandwidth becomes 20 MHz, data transmission using the NPCH may be executed from one communication device to the other communication device based on the fact that the SPCH is in an idle state. In this way, the ability to communicate using the second communication method notified by the communication device 100 to the other communication device does not match the actual ability to use the second communication method, which may result in inefficient communication.

[0021] In consideration of these circumstances, the communication device 100 in this embodiment identifies a predetermined frequency bandwidth configured to be used by the communication device itself, and disables communication using the second communication method based on the predetermined frequency bandwidth being a predetermined value. For example, the predetermined value is 20 MHz or less. With this configuration, the communication device 100 disables the use of NPCH access based on the frequency bandwidth used by the communication device itself being 20 MHz. This makes it possible to avoid inconsistencies between the frequency bandwidth used by the communication device itself and the availability of the second communication method. Furthermore, the communication device 100 notifies a communication device at a remote party that communication using the second communication method in the communication device itself is disabled. This makes it possible to avoid inconsistencies between the availability of the second communication method between the communication device 100 and the remote party. Therefore, for example, it is possible to prevent the remote party from transmitting using NPCH access even though the communication device 100 cannot use NPCH access.

[0022] The communication device 100 is configured to be able to communicate with a counterpart communication device using wireless frames that comply with at least one predetermined standard included in the IEEE 802.11 standard series. The predetermined standard defines a first communication method configured to enable communication by bonding a first channel and one or more second channels. In the first communication method, a transmission right is acquired using the first channel to perform communication. The predetermined standard also defines a second communication method in which, when the first channel cannot be used, a transmission right is acquired using a third channel included in the second channel to perform communication using at least the third channel.

[0023] The communication device 100 may acquire the frequency bandwidth configured to be used by the other communication device for communication and disable communication using the second communication method based on the frequency bandwidth being a predetermined value. With this configuration, the communication device 100 can disable the second communication method in its own device based on the frequency bandwidth used by the other communication device for communication being 20 MHz. This prevents transmission failures caused by the communication device 100 using the second communication method even though the other communication device cannot use the second communication method. Furthermore, when the frequency bandwidth configured in the communication device 100 is changed, the communication device 100 can enable communication using the second communication method based on the fact that the changed frequency bandwidth is no longer a predetermined value, and notify the other communication device of this. This allows efficient communication to be performed using the second communication method when a frequency bandwidth greater than 20 MHz becomes available after a connection with the other communication device is established and the second communication method becomes available. Furthermore, when the frequency bandwidth set in the communication device 100 is changed, the communication device 100 can disable communication using the second communication method based on the fact that the changed frequency bandwidth has reached a predetermined value, and notify the other communication device of this. As a result, when the frequency bandwidth used for communication becomes 20 MHz after a connection with the other communication device is established and the second communication method can no longer be used, the other communication device can avoid using the second communication method.

[0024] When performing multi-link communication with a communication device on the other end, the communication device 100 may specify a frequency bandwidth to be used for communication for each of the multiple links constituting the multi-link. The communication device 100 may then disable communication using the second communication method for each link based on the fact that each frequency bandwidth is a predetermined value. With this configuration, even when the frequency bandwidth used for each link differs, communication can be performed by effectively using the frequency bandwidth available for each link while avoiding unnecessary retransmissions and disconnections. When notifying that communication using the second communication method for any of the multiple links will be disabled, the communication device 100 may individually notify the link using the link. This makes it possible to apply the present technology even when establishing a connection for each link. Meanwhile, the communication device 100 may notify information identifying the multiple links for which communication using the second communication method will be disabled, using a specific link included in the multiple links. This reduces the overhead required for notification, thereby reducing wireless resource consumption.

[0025] The following describes in detail an example of the configuration of the communication device 100 that performs the above-described processing and the flow of the processing. Note that the following description focuses on communication between the AP 101 and the STA 102, but the same discussion can also be applied to communication between the AP 111 and the STA 112, or communication between multiple STAs, for example.

[0026] (Device configuration) 3 shows an example of the hardware configuration of the communication device 100 (AP 101 and STA 102) of this embodiment. As an example of the 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. Note that these are just examples, and the communication device 100 may have additional components not shown in FIG. 3, or some or all of the components shown in FIG. 3 may be replaced with other components having similar functions.

[0027] The storage unit 301 is configured to include one or more memories including ROM, RAM, etc. The storage unit 301 may store various information such as computer programs for causing each functional unit constituting the communication device 100 to perform various operations, and parameters for wireless 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 be configured to include storage media such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, and a DVD. The storage unit 301 may also be configured to include storage media such as multiple memories.

[0028] The control unit 302 is configured to include one or more processors including, for example, a CPU, an MPU, or the like. Note that CPU and MPU are abbreviations for Central Processing Unit and Micro Processing Unit, respectively. The control unit 302 controls the entire communication device 100 by executing a computer program stored in the storage unit 301. Note that the control unit 302 may control the entire communication device 100 in cooperation with the computer program stored in the storage unit 301 and an OS (Operating System). If the control unit 302 has multiple processors that can be implemented using a multi-core or the like, the entire communication device 100 may be configured to be controlled by the multiple processors.

[0029] Furthermore, the control unit 302 controls the functional unit 303 to execute predetermined processes such as wireless communication, image capture, printing, and projection. The functional unit 303 is configured to include hardware that enables the communication device 100 to execute the predetermined processes described above. If the communication device is a printer, the functional unit 303 is a printing device that prints image data acquired via the communication unit 306, for example. If the communication device is a scanner, the functional unit 303 is a reading device that outputs image data generated by scanning to the outside, for example, via the communication unit 306. If the communication device is a camera, the functional unit 303 is configured to include an image sensor and a lens, and outputs image data captured by the camera to the outside, for example, via the communication unit 306.

[0030] The input unit 304 receives various operations from the user. The input unit 304 may include, for example, a touch panel, hard keys, buttons, etc. The output unit 305 provides various outputs to the user. The output unit 305 may include a display, a speaker, etc. The output from the output unit 305 may be a screen display output on a display, an audio output from a speaker, a vibration output from a vibrator, etc. Note that the input unit 304 and the output unit 305 may both be implemented as a single module, such as a touch panel display. The input unit 304 and the output unit 305 may each be built into the communication device 100, or may be implemented as an external input / output device. If the input unit 304 and the output unit 305 are implemented as external input / output devices, the communication device 100 has an input / output interface for connecting to the input / output device.

[0031] The communication unit 306 executes control for controlling wireless communication compliant with the IEEE 802.11bn standard. Furthermore, the communication unit 306 may control wireless communication compliant with other IEEE 802.11 standard series, such as legacy standards, in addition to the IEEE 802.11bn standard, and control wired communication, such as a wired LAN. The communication unit 306 controls the antenna 307 to transmit and receive signals for wireless communication generated by the control unit 302. For example, the communication device 100 communicates data, such as image data, document data, and video data, with a partner communication device via the communication unit 306. The communication unit 306 is a so-called wireless chip and may itself include one or more processors and memories. Note that if the communication device 100 supports other wireless communication standards, such as the NFC standard and the Bluetooth standard, or wired communication, such as a wired LAN, in addition to the IEEE 802.11bn standard, the communication unit 306 may control communication compliant with these communication standards. Furthermore, when the communication device 100 is capable of performing wireless communication in accordance with a plurality of communication standards, the communication device 100 may be configured to have separate communication units and antennas compatible with each communication standard.

[0032] The antenna 307 is an antenna capable of detecting and emitting radio waves in, for example, the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. The antenna 307 may be configured to be capable of communication in the same frequency band. The antenna 307 may be, for example, a multi-band antenna capable of communication in multiple frequency bands. While FIG. 3 illustrates a configuration in which the communication device 100 has two antennas 307, the communication device 100 may have one or more antennas, or one or more antennas for each frequency band that the device can use. Furthermore, if the communication device 100 has multiple antennas, the communication device 100 may have a communication unit 306 for each antenna. The antenna 307 may be configured separately from the communication unit 306, or may be configured together with the communication unit 306 as a single module. The communication device 100 may be configured to be capable of performing carrier sensing of multiple SPCHs in parallel. In this case, the communication device 100 may have the number of communication units 306 and antennas 307 required to perform carrier sensing of multiple SPCHs in parallel.

[0033] (Functional configuration) 4 shows an example of the functional configuration of the communication device 100. The communication device 100 includes a frame control unit 401, a NAV detection unit 402, a wireless communication control unit 403, an NPCH access control unit 404, an NPCH access invalidation determination unit 405, a frame analysis unit 406, a bandwidth setting unit 407, and a bandwidth identification unit 408. These functional configurations can be realized, for example, by one or more processors that constitute the control unit 302 executing programs stored in one or more memories that constitute the storage unit 301. Note that some or all of these functional configurations may be implemented by dedicated hardware.

[0034] The frame control unit 401 generates a signal (frame) to be transmitted to the other communication device. The frame control unit 401 generates, for example, a data frame including user data to be transmitted to the other communication device. The frame control unit 401 also generates, for example, a management frame used for communication control. Management frames include a probe request frame and a probe response frame for detecting the other communication device. Management frames also include an association request frame and an association response frame for establishing a connection. Management frames include a disassociation frame for disconnecting a connection. Management frames include an authentication request frame and an authentication response frame for authentication. Similarly, management frames include an authentication commit frame and an authentication confirm frame. Management frames also include a deauthentication frame for deauthentication.

[0035] The NAV detection unit 402 sets the NAV of the PCH or SPCH based on the Duration value extracted by the frame analysis unit 406. For example, the NAV detection unit 402 sets the NAV of the PCH based on the Duration value included in a radio frame received in the PCH. The NAV detection unit 402 also sets the NAV of the SPCH based on a radio frame received in the SPCH during a period in which NPCH access is performed.

[0036] The wireless communication control unit 403 performs a transmission process for each frame generated by the frame control unit 401. The wireless communication control unit 403 also transfers frames received via the antenna 307 to the frame analysis unit 406. For example, the wireless communication control unit 403 can transmit or receive data frames using either the first or second communication method described above. As an example, when a wireless frame to be transmitted exists in the transmission buffer, the wireless communication control unit 403 performs carrier sensing of the PCH. Then, when the PCH is idle, the wireless communication control unit 403 transmits the wireless frame to be transmitted using the PCH or a channel formed by channel bonding between the PCH and one or more NPCHs. On the other hand, when the PCH is busy, the wireless communication control unit 403 attempts communication using the second communication method based on the determination result of the NPCH access invalidation determination unit 405. For example, the wireless communication control unit 403 performs carrier sensing on an SPCH that is set in advance for NPCH access. If no signal is detected in the SPCH and the NAV detection unit 402 does not set a NAV in the SPCH, the radio communication control unit 403 transmits the radio frame to be transmitted using one or more NPCHs including the SPCH.

[0037] The NPCH control unit 404 performs settings for performing NPCH access and control for communication via NPCH access. When establishing a link with a counterpart communication device, the NPCH control unit 404 may exchange setting information necessary for performing NPCH access and perform control based on the setting information. Note that the NPCH access control unit 404 may perform setting and control using information shared in advance by being defined in a standard or the like, without exchanging all of the setting information necessary with the counterpart communication device. For example, the NPCH access control unit 404 may store some setting information in advance and exchange another part of the setting information with the counterpart communication device when establishing a link with the counterpart communication device. In this case, after establishing a connection with the counterpart communication device, the NPCH access control unit 404 may exchange predetermined radio frames with the counterpart communication device to update at least some of the settings for NPCH access.

[0038] The NPCH access invalidation determination unit 405 determines whether to invalidate the use of the second communication method based on information about the frequency bandwidth used by the other communication device for communication acquired by the frame analysis unit 406 and the frequency bandwidth that the own device is configured to use for communication. The NPCH access invalidation determination unit 405 determines to invalidate NPCH access, for example, when the frequency bandwidth used by the other communication device for communication acquired by the frame analysis unit 406 is equal to a predetermined value. Furthermore, the NPCH access invalidation determination unit 405 determines to invalidate NPCH access, for example, when the frequency bandwidth used by the own device for communication is 20 MHz. The NPCH access invalidation determination unit 405 determines to invalidate NPCH access, for example, when the frequency bandwidth used in communication established with the other communication device is 20 MHz.

[0039] The frame analysis unit 406 analyzes a frame received from a remote communication device and acquires information and user data required for communication. For example, the frame analysis unit 406 analyzes a frame received from a remote communication device and acquires information and user data required for communication. For example, the frame analysis unit 406 acquires a Duration value from the received frame and notifies the NAV detection unit 402. The frame analysis unit 406 also acquires the frequency bandwidth used by the remote communication device for communication from the received frame and notifies the bandwidth setting unit 407. The frequency bandwidth used by the remote communication device for communication can be acquired from capabilities information received from the remote communication device. The capabilities information can be included in a beacon frame, a probe request frame, a probe response frame, an association request frame, or an association response frame. The capabilities information can also be included in a reassociation request frame, a reassociation response frame, or the like. The information indicating the frequency bandwidth can be a supported channel width set included in HT capabilities, VHT capabilities, or HE PHY capabilities. Furthermore, the information indicating the frequency bandwidth may be 20 MHz-Only Limited Capabilities Support included in EHT PHY Capabilities and UHR PHY Capabilities. Furthermore, the frame analysis unit 406 may acquire the frequency bandwidth used by the other communication device from an Action frame that notifies the frequency bandwidth, such as OMI, or a data frame that notifies the other frequency bandwidth. OMI is an abbreviation for Operating Mode Indication. For example, a change in frequency bandwidth after establishing a connection may be notified to the other communication device by OMI. Furthermore, a change in frequency bandwidth after establishing a connection may be notified to the other communication device using a Reassociation Request frame, a Reassociation Response frame, an Action frame, or the like.The method by which frame analysis unit 406 acquires the frequency band used by the other communication device is not limited to the above, and any method may be used. Note that frame analysis unit 406 may not analyze the target frame, and frame control unit 401 may notify the corresponding functional units of the information contained in each frame.

[0040] The bandwidth setting unit 407 sets the frequency bandwidth used by the communication device 100 for communication. For example, the bandwidth setting unit 407 may set the frequency bandwidth based on input received from a user or an application. Furthermore, the bandwidth setting unit 407 may set the frequency bandwidth used by the other communication device for communication, acquired by the frame analysis unit 406, as the frequency bandwidth used by the own device for communication. Furthermore, the bandwidth setting unit 407 may set the frequency bandwidth used in the connection established with the other communication device as the frequency bandwidth used by the own device for communication.

[0041] The bandwidth specifying unit 408 specifies a frequency bandwidth that the communication device 100 is configured to use for communication. For example, the bandwidth specifying unit 408 specifies the frequency bandwidth set in the bandwidth setting unit 407 as the frequency bandwidth that the device is configured to use for communication. Furthermore, if the device is unable to communicate using a frequency bandwidth other than the specific frequency bandwidth, the bandwidth specifying unit 408 specifies the specific frequency bandwidth as the frequency bandwidth that the device is configured to use for communication.

[0042] (Processing flow) Hereinafter, several examples of the flow of processing executed in communication between the AP 101 and the STA 102 in this embodiment will be described.

[0043] (Example of operation when connected) First, the operation of each communication device when a connection is established between the AP 101 and the STA 102 will be described. In this example, the use of the second communication method is disabled based on the frequency bandwidth configured for communication by the STA 102 being a predetermined value. In this example, the predetermined value of the frequency bandwidth is 20 MHz, but the predetermined value may be other values. For example, the predetermined value may be a value equal to or less than 20 MHz, such as 1 MHz, 2 MHz, 4 MHz, 8 MHz, or 16 MHz. The predetermined value may also be a value greater than 20 MHz. For example, if the first channel used to acquire the transmission right uses a frequency bandwidth other than 20 MHz, such as 10 MHz or 40 MHz, a value indicating the frequency bandwidth of the first channel may be used as the predetermined value. In this example, the first communication method is a communication method using a PCH or a channel formed by channel bonding of one or more PCHs and NPCHs, and the second communication method is a communication method using NPCH access. Each of the first communication method and the second communication method may be any communication method. 5A shows an example of a processing flow when the STA 102 determines whether to disable NPCH access based on the frequency bandwidth used by the STA 102 for communication. Also, FIG. 5B shows an example of a processing flow when the AP 101 determines whether to disable NPCH access based on the frequency bandwidth used by the STA 102 for communication. These processing flows may be executed, for example, when the STA 102 detects the AP 101 and connects to the AP 101.

[0044] First, the STA 102 identifies a predetermined frequency bandwidth configured for use by the STA 102 for communication (S501). For example, the STA 102 identifies a frequency band configured for use in communication as the predetermined frequency bandwidth. The STA 102 may accept a frequency bandwidth setting input by a user or an application. In this case, the STA 102 may set the predetermined frequency bandwidth for use by the STA 102 for communication based on the input setting. For example, even if the STA 102 has the capability to communicate using a frequency bandwidth greater than 20 MHz, the STA 102 may be configured to limit communication to a frequency bandwidth of 20 MHz or less. Such a setting may be input by a user via a user interface or may be executed by an application configured to configure the STA 102. Furthermore, if the STA 102 does not have the capability to communicate outside a specific frequency bandwidth, the STA 102 may identify this specific frequency bandwidth as the predetermined frequency bandwidth for use by the STA 102 for communication. For example, the specific frequency bandwidth may be 20 MHz. For example, a communication device that requires power-saving operation, such as a sensor, may be configured to be incapable of communicating outside a specific frequency bandwidth. In this example, the STA 102 determines that the predetermined frequency bandwidth set in the STA 102 is 20 MHz.

[0045] The STA 102 determines whether the specified predetermined frequency bandwidth is a predetermined value (S502). For example, the STA 102 determines whether the specified frequency bandwidth set in the STA 102 is 20 MHz. If the specified frequency bandwidth specified in S501 is equal to the predetermined value (YES in S502), the STA 102 disables the second communication method (S503). For example, the STA 102 disables communication using NPCH access. On the other hand, if the specified frequency bandwidth specified in S501 is greater than the predetermined value (NO in S502), the STA 102 keeps communication using the second communication method enabled. In this example, the STA 102 disables communication using NPCH access based on the fact that the specified frequency bandwidth specified in S501 is 20 MHz. If the STA 102 disables communication using NPCH access, the STA 102 does not attempt to perform NPCH access if the PCH cannot be used in communication with the AP 101. For example, if the PCH is unavailable, the STA 102 does not perform carrier sensing on the SPCH, thereby reducing the power consumed by the STA 102 to attempt NPCH access.

[0046] When the STA 102 disables communication using the second communication method, the STA 102 notifies the AP 101 that use of the second communication method is disabled. In this case, the STA 102 may notify the AP 101 that NPCH access is disabled, may notify that the STA 102 is not capable of performing NPCH access, or may notify that NPCH access will not be performed. For example, the STA 102 may make the notification using a frame for establishing a connection with the AP 101. The frame for establishing a connection transmitted by the STA 102 may be a Probe Request frame, an Association Request frame, a Reassociation Request frame, or the like. The AP 101 disables communication using the second communication method with the STA 102 based on the notification received from the STA 102. This makes it possible for the AP 101 to avoid using the second communication method in communication with the STA 102.

[0047] If communication using the second communication method remains enabled, the STA 102 may notify the AP 101 that the second communication method is enabled. When making the notification, the STA 102 may notify the AP 101 that NPCH access is enabled, may notify that the STA 102 has the capability to perform NPCH access, or may notify that NPCH access will be performed. The AP 101 may enable communication using the second communication method for the STA 102 based on receiving the notification from the STA 102. As a result, the AP 101 may use NPCH access in communication with the STA 102. When communication using the second communication method is enabled, the STA 102 attempts NPCH access if the PCH is unavailable in communication with the AP 101. For example, the STA 102 performs carrier sensing on the SPCH if the PCH is unavailable. This increases the opportunities for the STA 102 to transmit, enabling efficient use of frequency resources.

[0048] The above description has been given using an example of a processing flow when the STA 102 determines whether to disable the second communication method based on the frequency bandwidth used by the STA 102 for communication. The AP 101 may execute a similar process when determining whether to disable NPCH access based on the frequency bandwidth used by the STA 102 for communication. The AP 101 may notify the STA 102 that it will disable the use of the second communication method using a Probe Response frame, an Association Response frame, a Reassociation Response frame, or the like. When the AP 101 disables the use of the second communication method, the AP 101 may notify the STA 102 using a Beacon frame. In this case, the STA 102 may acquire information that the AP 101 has disabled the use of the second communication method before starting a connection procedure with the AP 101.

[0049] Next, with reference to FIG. 5B, an example of operation will be described in which the AP 101 disables the use of the second communication method of its own device based on the frequency bandwidth used by the STA 102, a counterpart communication device, for communication. First, the AP 101 acquires information for identifying the predetermined frequency bandwidth configured for the STA 102 to use for communication (S504). For example, if a frame transmitted by the STA 102 to establish a connection includes information identifying the predetermined frequency bandwidth configured for the STA 102 to use for communication, the AP 101 can acquire the predetermined frequency bandwidth by receiving this frame. The frame transmitted by the STA 102 to establish a connection can be a Probe Request frame, an Association Request frame, a Reassociation Request frame, or the like. In this example, the AP 101 acquires information identifying that the predetermined frequency bandwidth set for the STA 102 is 20 MHz.

[0050] The AP 101 determines whether the predetermined frequency bandwidth configured for communication by the STA 101 is a predetermined value (S505). For example, the AP 101 determines whether the predetermined frequency bandwidth set for the STA 102 is 20 MHz. If the predetermined frequency bandwidth identified in S504 is equal to the predetermined value (YES in S505), the AP 101 disables communication with the STA 102 using the second communication method (S506). On the other hand, if the predetermined frequency bandwidth identified in S504 is greater than the predetermined value (NO in S505), the AP 101 enables communication with the STA 102 using the second communication method. In this example, the AP 101 disables communication with the STA 102 using NPCH access based on the fact that the predetermined frequency bandwidth identified in S504 is 20 MHz. If the AP 101 disables communication with the STA 102 using NPCH access, the AP 101 will not attempt to perform NPCH access if the PCH cannot be used for communication with the STA 102. For example, if the PCH is unavailable, the AP 101 does not perform carrier sensing or data transmission on the SPCH. This allows the AP 101 to avoid transmission failures to the STA 102, thereby reducing retransmission processes and disconnections.

[0051] When the AP 101 disables communication using the second communication method for the STA 102, the AP 101 may notify the STA 102 that use of the second communication method is disabled. In this case, the AP 101 may notify the STA 102 that NPCH access is disabled, may notify the STA 102 that it is not capable of performing NPCH access, or may notify the STA 102 that NPCH access will not be performed. The notification by the AP 101 may be performed using a Probe Response frame, an Association Response frame, a Reassociation Response frame, or the like. Note that, if there is a STA connected to the AP 101 other than the STA 102, the AP 101 may perform the notification using a frame used for individual communication with the STA 102. This allows the AP 101 to disable use of the second communication method only for the STA 101 while allowing use of the second communication method with the other STAs. On the other hand, if use of the second communication method is disabled for all STAs connected to the AP 101, the AP 101 may disable use of the second communication method itself for the AP 101. For example, if the frequency bandwidth used by all STAs connected to the AP 101 for communication is 20 MHz, the AP 101 may disable the use of the second communication method itself. This allows the AP 101 to, for example, not perform carrier sensing of the SPCH when the PCH is unavailable, thereby reducing the power consumption required for this. In this case, the AP 101 may use a Beacon frame to notify that the AP 101 has disabled the use of the second communication method.

[0052] When communication using NPCH access for the STA 102 is enabled, the AP 101 notifies the STA 102 that use of the NPCH is enabled. In this case, the AP 101 may notify the STA 102 that NPCH access will be performed. This allows the STA 102 to use NPCH access in communication with the AP 101. Furthermore, when the AP 101 enables communication using NPCH access for the STA 102, it attempts NPCH access when the PCH cannot be used in communication with the STA 102. For example, when the PCH cannot be used, the AP 101 performs carrier sensing on the SPCH. This increases the opportunities for the AP 101 to transmit, enabling efficient use of frequency resources.

[0053] The above description has been given using an example of a processing flow when the AP 101 determines whether to disable the second communication method based on the frequency bandwidth used by the STA 102, a counterpart communication device, for communication. The same processing can be performed when the STA 102 determines whether to disable NPCH access based on the frequency bandwidth used by the AP 101, a counterpart communication device, for communication. The STA 102 can acquire information specifying the frequency bandwidth used by the AP 101 for communication using a Probe Response frame, an Association Response frame, a Reassociation Response frame, or the like. The STA 102 can also acquire information specifying the frequency bandwidth used by the AP 101 for communication using a Beacon frame. Furthermore, the STA 102 can notify the AP 101 that the STA 102 will disable use of the second communication method using a Probe Request frame, an Association Request frame, a Reassociation Request frame, or the like.

[0054] (Example of communication behavior) An example of the operation of the communication device 100 when communicating using a first communication method and a second communication method will be described. In this example, the first communication method is a method of communicating using a PCH or a channel formed by bonding a PCH and one or more NPCHs. The second communication method is a method of acquiring a transmission right using an SPCH when a PCH is unavailable and communicating using at least the SPCH. For example, the second communication method is NPCH access. The communication device 100 determines whether a PCH is available when transmitting data, and if it determines that the PCH is unavailable, it determines whether the second communication method is disabled. If the second communication method is disabled, the communication device 100 waits for transmission until the PCH becomes available. On the other hand, if the second communication method is not disabled, the communication device 100 attempts NPCH access.

[0055] FIG. 6 shows an example of a flow when the communication device 100 transmits data. When the communication device 100 detects that data has been input to its transmission queue (S601), it initiates a channel access procedure to transmit the data. First, the communication device 100 performs carrier sensing on the PCH (S602). For example, the communication device 100 measures a backoff counter in the PCH and determines whether the PCH is in an idle state. If it determines that the PCH is in an idle state (YES in S603), the communication device 100 transmits a signal using a first communication method that uses one or more channels including the PCH (S604). Note that after determining that the PCH is in an idle state, the communication device 100 may perform carrier sensing on the NPCH for a predetermined period of time. The predetermined period may be a PIFS period immediately before the start of transmission. Furthermore, the communication device 100 may perform carrier sensing on the NPCH in parallel with carrier sensing on the PCH. The communication device 100 may determine a channel to use for transmission based on the results of carrier sensing performed on each of the PCH and the NPCH, and transmit a signal. For example, the communication device 100 may transmit a signal using a channel formed by channel bonding of the PCH and one or more NPCHs determined to be in an idle state.

[0056] On the other hand, if the communication device 100 detects a signal on the PCH during carrier sensing (NO in S603), it sets the NAV for the PCH using the duration indicated in the Duration field included in the received signal. Then, the communication device 100 checks whether the second communication method is enabled. The communication device 100 may check whether the second communication method is disabled. For example, if the second communication method is disabled (NO in S605), the communication device 100 waits until the PCH enters an idle state (S606). On the other hand, if the second communication method is enabled, that is, if NPCH access is not disabled (YES in S605), the communication device 100 determines whether the signal detected on the PCH is transmitted from a communication device belonging to the network 103. For example, the communication device 100 may determine whether the signal is from its own BSS or an OBSS based on whether the BSS Color field included in the received signal matches the BSS Color of its own BSS. Furthermore, the communication device 100 can determine whether a received signal is from its own BSS or from an OBSS based on whether values ​​stored in a destination field, a source field, etc. included in the signal match parameters of its own BSS. For example, if the signal detected in the PCH is a signal from the OBSS (YES in S607), the communication device 100 executes NPCH access. On the other hand, if the signal detected in the PCH is a signal from its own BSS (NO in S607), the communication device 100 determines not to execute NPCH access and waits until the PCH enters an idle state (S606).

[0057] When performing NPCH access, the communication device 100 performs carrier sensing on the SPCH. If no signal is detected on the SPCH, the communication device 100 measures a backoff counter in the same manner as in carrier sensing on the PCH, and determines whether the SPCH is in an idle state. If it is determined that the SPCH is in an idle state (YES in S608), the communication device 100 transmits a signal by a second communication method using one or more NPCHs including the SPCH (S609). After determining that the SPCH is in an idle state, the communication device 100 may perform carrier sensing on other NPCHs for a predetermined period, similar to carrier sensing on the PCH. The communication device 100 may determine a channel to use for transmission based on the results of carrier sensing performed on the SPCH and other NPCHs, and transmit a signal. On the other hand, if the communication device 100 detects a signal on the SPCH (NO in S608), it cancels NPCH access and postpones transmission until the NAV period set on the PCH expires (S606). If multiple SPCHs are set, the communication device 100 may continue the NPCH access procedure until it confirms that all SPCHs are busy. If all SPCHs are busy, the communication device 100 postpones transmission until the NAV period set in the PCH expires.

[0058] In this way, the communication device 100 operates so as not to execute the second communication method when the frequency bandwidth configured to be used for communication is equal to a predetermined value. For example, the communication device 100 does not perform NPCH access when the frequency bandwidth configured to be used for communication is 20 MHz. With this configuration, for example, even if the AP 101 itself can operate at a frequency bandwidth greater than 20 MHz, the AP 101 does not perform NPCH access when the STA 102 operates at 20 MHz. This prevents the AP 101 from performing NPCH access even when the STA 102 is unavailable, thereby avoiding retransmission processing and disconnection by the AP 101. Furthermore, when the AP 101 determines that the PCH is busy, the AP 101 does not perform carrier sensing of the SPCH, thereby reducing the power consumption required for this processing.

[0059] (Example of behavior when communication device settings are changed) In the communication device 100, the frequency bandwidth to be used may be changed after establishing a connection with a communication device at a different location. For example, the communication device 100 may change the frequency bandwidth to be used for communication by changing the network configuration (network settings) based on input from a user or an application. The network configuration (network settings) may include, for example, the number of wireless interfaces to be used by the communication device 100, the frequency bands and frequency channels to be used for each wireless interface, the bandwidth to be used for communication, whether or not power saving operation is enabled, and the corresponding security method. The network configuration (network settings) may also include settings other than these. The communication device 100 may disable or enable the use of a second communication method based on a change in the frequency bandwidth to be used for communication set in the communication device 100. For example, suppose that when the communication device 100 establishes a connection with a communication device at a different location, the frequency bandwidth to be used for communication is set to 20 MHz, and therefore the use of the second communication method is disabled. In this case, the frequency bandwidth to be used for communication set in the communication device 100 is changed to a frequency bandwidth greater than 20 MHz, and the communication device 100 may enable the use of the second communication method. On the other hand, when communication device 100 establishes a connection with a communication device of a different party, a frequency bandwidth greater than 20 MHz is set as the frequency bandwidth to be used for communication, thereby enabling the use of the second communication method. In this case, if the frequency bandwidth to be used for communication set in communication device 100 is changed to 20 MHz, communication device 100 may disable the use of the second communication method. In this manner, communication device 100 may enable or disable the use of the second communication method based on a change in the frequency bandwidth of its own device during communication with another communication device, thereby resolving a mismatch between the frequency bandwidth to be used and the availability of the second communication method. Note that, if the frequency bandwidth to be used for communication is changed in the communication device of the different party, communication device 100 may acquire the changed frequency bandwidth from the communication device of the different party.In this case, the communication device 100 can enable or disable the use of the second communication method based on a change in the setting of the frequency bandwidth used for communication of the other communication device, just as when the frequency bandwidth used for communication of the own device is changed.

[0060] 7 is a flowchart showing an example of the operation of the communication device 100 when the frequency bandwidth used for communication is changed during communication with a communication device of a remote party. FIG. 7(A) shows an example of a processing flow when the STA 102 determines whether to disable the use of the second communication method based on a change in the frequency bandwidth used for communication by the device itself. FIG. 7(B) shows an example of a processing flow when the AP 101 determines whether to disable the use of NPCH access based on a change in the frequency bandwidth used for communication by the STA 102. These processing flows may be executed, for example, when a connection between the AP 101 and the STA 102 is established and the setting of the frequency bandwidth used for communication by the STA 102 is changed while communication between the AP 101 and the STA 102 is being performed. Note that in FIG. 7, the same reference numerals are assigned to operations similar to those in FIG. 5, and descriptions thereof will be omitted.

[0061] First, the STA 102 detects that the setting of the frequency bandwidth used for communication in the STA 102 has been changed (S701). For example, the STA 102 may accept a change in the setting of the frequency bandwidth from a user via a user interface provided for changing the network configuration of the STA 102. If the change in the network configuration of the STA 102 includes a change in the frequency bandwidth used for communication, the STA 102 identifies the frequency bandwidth (S501). The STA 102 determines whether the changed frequency bandwidth is equal to a predetermined value (S502). For example, the STA 102 determines whether the changed frequency bandwidth is 20 MHz. If the changed frequency bandwidth is equal to the predetermined value (YES in S502), the STA 102 disables communication using the second communication method (S503). On the other hand, if the changed frequency bandwidth is greater than the predetermined value (NO in S502), the STA 102 keeps communication using NPCH access enabled.

[0062] Next, with reference to FIG. 7B, an example of the operation of the AP 101 when determining whether the AP 101 can implement the second communication method based on a change in the frequency bandwidth used by the STA 102 for communication will be described. First, the AP 101 detects that the setting of the frequency bandwidth used for communication in the STA 102 has been changed (S701). For example, if the network configuration in the STA 102 has been changed, the STA 102 may notify the AP 101 of the changed setting. For example, the STA 102 may perform this notification using an Action frame, a Reassociation Request frame, or the like. The AP 101 may detect that the network configuration in the STA 102 has been changed based on this notification. If the notification from the STA 102 includes information specifying a change in the frequency bandwidth used for communication, the AP 101 may obtain the changed frequency bandwidth from this information (S504). Note that the AP 101 may obtain the change in the changed frequency bandwidth by receiving a frame including an Operating Mode Indication (OMI) from the STA 102. The OMI is information used by the communication device 100 transmitting the OMI to notify the other communication device that it operates in a frequency bandwidth smaller than the frequency bandwidth that the communication device 100 can use. In addition, the AP 101 can obtain changes in the network configuration of the STA 102 based on a Deauthentication frame, a Disassociation frame, or the like.

[0063] The AP 101 determines whether the acquired frequency bandwidth is equal to a predetermined value (S505). For example, the AP 101 determines whether the acquired frequency bandwidth is 20 MHz. If the acquired frequency bandwidth is equal to the predetermined value (YES in S505), the AP 101 disables the use of the second communication method for the STA 102 (S506). On the other hand, if the acquired frequency bandwidth is different from the predetermined value (NO in S505), the AP 101 enables the use of the second communication method for the STA 102.

[0064] When the availability of the second communication method is changed due to a change in the setting of the frequency bandwidth used by the AP 101 or the STA 102 for communication, the AP 101 or the STA 102 may notify the other communication device. For example, when the STA 102 enables the use of the second communication method that was previously disabled based on the determination result of S502, the STA 102 notifies the AP 101 that the use of the second communication method is enabled. In this case, the STA 102 may notify the AP 101 that the use of NPCH access is enabled, may notify the AP 101 that it has the capability to perform NPCH access, or may notify the AP 101 that it can perform NPCH access. Furthermore, when the STA 102 disables the use of the second communication method that was previously enabled based on the determination result of S502, the STA 102 notifies the AP 101 that the use of the second communication method is disabled. In this case, the STA 102 may notify the AP 101 that the use of NPCH access is disabled, may notify the AP 101 that it does not have the capability to perform NPCH access, or may notify the AP 101 that it will not perform NPCH access. For example, the STA 102 can make this notification using an Action frame, a Reassociation Request frame, etc. Based on the notification received from the STA 102, the AP 101 enables or disables the use of the second communication method for the STA 102.

[0065] Similarly, if the AP 101 enables the use of the second communication method that was previously disabled based on the determination result of S505, the AP 101 notifies the STA 102 that the second communication method will be enabled. In this case, the AP 101 may notify the STA 102 that the use of NPCH access will be enabled, or that the AP 101 has the capability to perform NPCH access, or that the AP 101 can perform NPCH access. Furthermore, if the AP 101 disables the use of the second communication method that was previously enabled based on the determination result of S505, the AP 101 notifies the STA 102 that the use of the second communication method will be disabled. In this case, the AP 101 may notify the STA 102 that the NPCH access will be disabled, or that the AP 101 does not have the capability to perform NPCH access, or that the AP 101 will not use NPCH access. For example, the AP 101 may make this notification using an Action frame, a Reassociation Response frame, or the like. The STA 102 enables or disables the use of the second communication method based on the notification received from the AP 101. In this way, by notifying whether the use of the second communication method is enabled or disabled, it is possible to avoid a state in which the AP 101 and the STA 102 disagree on whether the second communication method can be used.

[0066] (Example of a message sequence between AP101 and STA102) 8 shows an example of a sequence of messages exchanged between AP 101 and STA 102. In this example, when a connection between AP 101 and STA 102 is established, both AP 101 and STA 102 are capable of using a frequency bandwidth larger than a predetermined value. That is, immediately after establishing the connection, AP 101 and STA 102 can communicate data using either the first communication method or the second communication method. Then, it is assumed that the frequency bandwidth used for communication in STA 102 is subsequently changed to 20 MHz. As a result, AP 101 and STA 102 disable the second communication method. That is, after the second communication method is disabled, AP 101 and STA 102 communicate data using the first communication method without using the second communication method.

[0067] First, the AP 101 and the STA 102 execute a connection procedure (F801 to F806). For example, the AP 101 periodically transmits a Beacon frame (F801). The STA 102 may detect the presence of the AP 101 by receiving the Beacon frame. The AP 101 may use the Beacon frame to notify that the AP 101 has disabled use of the second communication method. Instead of notifying that use of the second communication method has been disabled, the AP 101 may notify information indicating that the AP 101 does not have the ability to use the second communication method. In these cases, the STA 102 may disable use of the second communication method in the AP 101 by receiving the Beacon frame. The Beacon frame may also include information that can identify the frequency bandwidth that the AP 101 uses for communication. For example, the AP 101 may include information indicating a frequency bandwidth such as 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 320 MHz in the Beacon frame. The STA 102 may disable the use of the second communication method in its own device based on the fact that the frequency bandwidth used by the AP 101 for communication is 20 MHz.

[0068] The STA102 transmits a Probe Request frame (F802). The STA102 may use the Probe Request frame to notify information indicating that the STA102 has disabled the use of the second communication method. For example, if a Beacon frame transmitted by the AP101 indicates that the frequency bandwidth used by the AP101 for communication is 20 MHz, the STA102 may disable the use of the second communication method. Furthermore, the STA102 may disable the use of the second communication method based on the fact that the frequency bandwidth used by the STA102 for communication is 20 MHz. In these cases, the STA102 may use the Probe Request frame to notify the AP101 that the use of the second communication method has been disabled. By receiving the Probe Request frame including such a notification, the AP101 may disable the use of the second communication method for the STA102. Furthermore, the STA102 may use the Probe Request frame to indicate the frequency bandwidth used by the STA102 for communication. For example, the STA102 may indicate that the frequency bandwidth it uses for communication is 20 MHz by transmitting a Probe Request frame with a frequency bandwidth of 20 MHz. The STA102 may also transmit a Probe Request frame including information indicating that the frequency bandwidth it uses for communication is 20 MHz. The AP101 may determine to disable use of the second communication method based on the fact that the frequency bandwidth used by the STA102 for communication is 20 MHz. Note that, if the STA102 can use a frequency bandwidth greater than 20 MHz, the STA102 may indicate to the AP101 the frequency bandwidth it uses for communication by transmitting a Probe Request frame with the frequency bandwidth to be used. Note that the STA102 may also transmit a Probe Request frame including information indicating the frequency bandwidth it uses for communication. In these cases, the AP101 may enable use of the second communication method for the STA102. Note that these notifications may be made using an Association Request frame or a Reassociation Request frame, which will be described later.

[0069] In response to the Probe Request frame, the AP 101 transmits a Probe Response frame (F803). The AP 101 may use the Probe Response frame to notify information indicating that the AP 101 has disabled the use of the second communication method. For example, if the Probe Request frame received from the STA 102 indicates that the frequency bandwidth used by the STA 102 for communication is 20 MHz, the AP 101 may disable the use of the second communication method. In this case, the AP 101 may use the Probe Response frame to notify the STA 102 that the use of the second communication method has been disabled. The STA 102 may disable the use of the second communication method in the AP 101 by receiving the Probe Response frame including information indicating that the AP 101 has disabled the use of the second communication method. Similarly to the Beacon frame, the Probe Response frame may include information indicating the frequency bandwidth used by the AP 101 for communication. In this case, the STA 102 may determine to disable use of the second communication method based on the fact that the frequency bandwidth used for communication by the AP 101 is 20 MHz. Then, the STA 102 may notify the AP 101 that use of the second communication method has been disabled by using a subsequent Association Request frame or the like.

[0070] In this way, the AP 101 and the STA 102 can use a Beacon frame, a Probe Request frame, and a Probe Response frame to notify the disabling of the use of the second communication method in their own devices and the frequency bandwidth that their own devices will use for communication. The AP 101 and the STA 102 can perform these notifications using the subsequent Authentication frame (F804), Association Request frame (F805), and Association Response frame (F806). That is, one communication device can use a specific frame to notify the frequency bandwidth that its own device will use for communication, and the other communication device can use a subsequent frame to notify the other communication device that it has disabled the use of the second communication method based on this notification. Alternatively, one communication device can unilaterally notify the other communication device that it has disabled the use of the second communication method based on the frequency bandwidth that its own device will use for communication.

[0071] When the STA 102 receives the Association Response frame transmitted by the AP 101, a connection between the AP 101 and the STA 102 is established. The AP 101 and the STA 102 may subsequently execute a 4-Way Handshake (4WHS). The AP 101 and the STA 102 may negotiate the frequency bandwidth to be used for communication in the procedure until the connection is established, and may disable the use of the second communication method based on the result of this negotiation. In this case, the AP 101 or the STA 102 may notify the other communication device that the use of the second communication method has been disabled using an Action frame.

[0072] The AP 101 and the STA 102 communicate data using the established connection (F807). In this example, since both the AP 101 and the STA 102 can use a frequency bandwidth greater than 20 MHz, communication is performed with the second communication method enabled. For example, when the PCH is busy, the AP 101 and the STA 102 perform carrier sense and data transmission on the SPCH. Here, assume that the frequency bandwidth used for communication in the STA 102 is changed to 20 MHz. Based on this change, the STA 102 may disable the second communication method. In this case, the STA 102 notifies the AP 101 that the second communication method has been disabled (F808). This notification may be performed using an Action frame. For example, the STA 102 may transmit an Action frame to the AP 101 that includes information indicating that the second communication method has been disabled. This may allow the AP 101 to recognize that the STA 102 will not use the second communication method. Furthermore, the STA 102 may send a notification including information indicating the changed frequency bandwidth. For example, the STA 102 may notify the AP 101 that the frequency bandwidth used for communication has been changed to 20 MHz. For example, the STA 102 may notify the AP 101 that the frequency bandwidth used by the STA 102 for communication has been changed by transmitting a frame including an OMI indicating that the frequency bandwidth is 20 MHz. The STA 102 may send this notification using an Action frame indicating that the frequency bandwidth is 20 MHz. In these cases, the AP 101 may determine to disable the use of the second communication method. When the AP 101 disables the use of the second communication method in the AP 101, the AP 101 may notify the STA 102 of this using an Action frame or the like (F809). Thereafter, the AP 101 and the STA 102 perform data communication with the use of the second communication method disabled (F810). For example, when the PCH is busy, the AP 101 and the STA 102 do not perform carrier sensing or data transmission on the SPCH.

[0073] The AP 101 may individually enable or disable the use of the second communication method with each STA 102. For example, when the AP 101 receives a Probe Request frame with a 20 MHz frequency bandwidth from the STA 102, the AP 101 may be communicating with another STA using a 40 MHz frequency bandwidth with the second communication method enabled. In this case, the AP 101 may maintain communication with the other STA while disabling the second communication method for communication with the STA 102. For example, the AP 101 may notify the STA 102 in a frame received by multiple STAs, such as a Beacon frame, that the AP 101 is capable of using the second communication method or that the second communication method is available. The AP 101 may then notify the STA 102 in a frame used for communication with the STA 102 that the second communication method will be disabled. For example, the AP 101 may notify the STA 102 using a Probe Response frame, an Association Response frame, a Reassociation Response frame, an Action frame, or the like. When the AP 101 has disabled the second communication method with all STAs connected to the AP 101, the AP 101 may also notify the STAs that the second communication method will be disabled in frames received by multiple STAs, such as Beacon frames. For example, when the AP 101 has disconnected from other STAs using a 40 MHz frequency bandwidth and is connected only to STA 102 using a 20 MHz frequency bandwidth, the AP 101 may notify the STAs in the Beacon frame that the second communication method will be disabled.

[0074] (Frame format example) An example of the format of information used by the communication device 100 to notify the other communication device that the second communication method will be disabled will be described below. In this example, the second communication method will be described as NPCH access. FIG. 9A shows an example of the configuration of a UHR Capabilities element. The UHR Capabilities element is an information element (IE) included in, for example, a Beacon frame, a Probe Response frame, an Association Response frame, etc. IE is an abbreviation for Information Element. The UHR Capabilities element can also be included in a Probe Request frame and an Association Request frame. The UHR Capabilities element can also be included in a Reassociation Request frame, a Reassociation Response frame, etc. The UHR Capabilities element includes an Element ID field 901, a Length field 902, and an Extended Element ID field 903. The UHR Capabilities element can also include a Secondary Transmit Capable (STC) field 904 and one or more Secondary Receive Capable (SRC) fields. For example, a UHR Capabilities element may include four SRC fields: an SRC1 field 905, an SRC2 field 906, an SRC3 field 907, and an SRC4 field 908. The type of element is indicated by the combination of the Element ID field 901 and the Extended Element ID field 903. For example, an element with the Element ID field 901 set to 255 and the Extended Element ID field 903 set to 138 is a UHR Capabilities element. The Length field 602 indicates the length of this element.

[0075] The STC field 904 indicates whether the communication device 100 performs transmission processing in NPCH access. The SRC1 field 905 indicates that the number of channels that the communication device 100 can receive is 1 when the other communication device transmits using NPCH access. Similarly, the SRC2 field 906 indicates that the number of channels that the communication device 100 can receive in parallel (the number of receivable channels) is 2 when the other communication device transmits using NPCH access. The SRC3 field 907 indicates that the number of receivable channels is 3. The SRC4 field 908 indicates that the number of receivable channels is 4. For example, when only the SRC1 field 905 is set to 1 and the SRC2 field 906 to the SRC4 field 908 are each set to 0, this indicates that the number of receivable channels is 1. Furthermore, when the STC field 904 is set to 0 and the SRC1 field 905 to the SRC4 field 908 are each set to 0, this indicates that NPCH access is disabled.

[0076] The STC field 904 and the SRC1 field 905 to the SRC4 field 908 may be configured as one field. In this case, one bit indicates whether the own device performs both transmission and reception of NPCH access. That is, when this bit is set to 1, it may indicate that NPCH access is enabled, and when this bit is set to 0, it may indicate that NPCH access is disabled. Also, the SRC1 field 905 to the SRC4 field 908 may be configured as one field. In this case, one bit indicates whether the own device performs reception processing in NPCH access. That is, when NPCH access is enabled, this bit and the STC field 904 may both be set to 1. Also, when NPCH access is disabled, this bit and the STC field 904 may both be set to 0. Note that when the communication device 100 can perform reception processing on five or more channels in parallel, an SRC5 field (not shown), an SRC6 field (not shown), etc. may be provided. In this case, it is possible to indicate to the other communication device that parallel reception processing is possible for more channels.

[0077] The number of channels that the communication device 100 can receive in parallel may be determined based on the number of receiving circuits included in the communication device 100. For example, the number of channels that the communication device 100 can receive in parallel may be equal to the number of receiving circuits included in the communication device. By having each receiving circuit correspond to a respective channel (such as an SPCH), reception processing of signals received on each of multiple channels may be performed in parallel. Furthermore, the number of channels that the communication device 100 can receive in parallel may be the number of channels that the communication device 100 can carrier sense in parallel (the number of carrier-senseable channels). Note that even if the communication device 100 has only one receiving circuit, the communication device 100 may perform carrier sense in parallel on multiple channels, select one channel from the channels on which a signal is detected, and perform reception processing of the received signal. Furthermore, the number of channels that the communication device 100 can receive in parallel may be the number of receiving antennas included in the communication device 100. If each antenna is associated with a different channel so as to be able to process signals, the communication device 100 may perform reception processing of signals received on each channel in parallel. Similarly, the communication device 100 may notify the other communication device of the number of carrier senseable channels and the number of receivable channels using separate fields.

[0078] 9(B) shows another example of the configuration of the UHR Capabilities element. In FIG. 9(B), a Secondary Receive Capable (SRC) field 909 is provided instead of the SRC1 field 605 to the SRC4 field 608 in FIG. 9(A). The SRC field 909 can be configured with, for example, two bits. As an example, the communication device 100 can notify that the use of NPCH access is disabled by setting the STC field 904 to 0 and the SRC field 909 to 0. Furthermore, when the number of receivable channels is 1, 2, or 4, the communication device 100 can set the value of the SRC field 909 to 1, 2, or 3, respectively. Note that when the number of receivable channels is 3, the communication device 100 may set the value of the SRC field 909 to 3. Furthermore, the communication device 100 may be provided with an SRC field 909 for indicating whether the reception process in NPCH access is disabled for the communication device 100 itself, and another field (a number of receivable channels field, not shown) for indicating the number of receivable channels. In this case, the SRC field 909 indicates that the use of NPCH access is not disabled for the communication device 100, and the number of receivable channels field indicates the number of receivable channels. Note that when the above elements are used as information indicating the capabilities of the communication device 100, a separate element may be provided for indicating whether NPCH access is disabled based on the frequency bandwidth used by the communication device 100. In this case, the above element indicates that the communication device 100 has the capability to perform NPCH access, while another element may indicate whether NPCH access is actually enabled. In this example, the capabilities related to the transmission process and the capabilities related to the reception process in NPCH access are indicated by separate fields, but the transmission and reception capabilities may be indicated by a single field. For example, a one-bit field indicating NPCA transmission and reception capabilities may be provided. For example, if this bit is set to 0, it may indicate that transmission and reception via NPCA access is not supported, and if this bit is set to 1, it may indicate that transmission and reception via NPCA access is supported.In this example, the UHR Capabilities element includes information indicating that the communication device 100 disables the use of the second communication method. However, this information may be included in another element. For example, the information indicating that the use of the second communication method is disabled may be included in an Extended Capabilities field. In this case, the communication device 100 may notify other communication devices that do not comply with the IEEE 802.11bn standard but are capable of performing NPCH access. Furthermore, if a new element or field for notifying information indicating that the use of the second communication method is disabled is defined in the standard, the communication device 100 may perform the notification using this element or field. The new element or field may be formulated so that information required for NPCH access can be flexibly exchanged between communication devices.

[0079] When the communication device 100 disables the use of the second communication method after a connection with the other communication device is established, the communication device 100 can notify the other communication device using an Action frame. FIG. 10 shows an example of the configuration of a field included in an Action frame used to notify that the use of the second communication method will be disabled. This field can be called an NPCH Operating Mode Notification frame Action field. This field may also be called by other names. This field includes a Category field 1001, a Protected UHR Action field 1002, a Dialog Token field 1003, and an NPCH Access Control field 1004. The NPCH Operating Mode Notification frame Action field may also include an NPCH Access Parameter Update field 1005. The Category field 1001 indicates the category of this Action field. For example, the Category field 1001 stores an identification number corresponding to Protected UHR. The Protected UHR Action field 1002 indicates an identifier of this Action field in the Protected UHR category. For example, the Protected UHR Action field 1002 stores an identification number indicating the NPCH Operating Mode Notification frame Action field. The Dialog Token field 1003 indicates an identifier for executing a series of information exchanges between the communication device 100 and the other communication device. For example, an identifier assigned by the requesting communication device is stored in the Dialog Token field 1003. The responding communication device stores the value contained in the received Dialog Token field 1003 in the Dialog Token field 1003 of a response frame and transmits it.

[0080] The NPCH Access Control field 1004 includes an NPCH Access Mode field 1006 and an NPCH Access Parameter Update Control field 1007. The NPCH Access Mode field 1006 indicates whether or not the use of NPCH access is disabled. For example, the communication device 100 notifies that NPCH access is enabled by setting a value of 1 in this field. On the other hand, the communication device 100 notifies that NPCH access is disabled by setting a value of 0 in this field. The NPCH Access Parameter Update Control field 1007 indicates whether or not the NPCH Access Parameter Update field 1005 is included. For example, a value of 1 in the NPCH Access Parameter Update Control field 1007 indicates that the NPCH Access Parameter Update field 1005 is included. On the other hand, a value of 0 in the NPCH Access Parameter Update Control field 1007 indicates that the NPCH Access Parameter Update field 1005 is not included. The NPCH Access Parameter Update field 1005 includes a Secondary Primary Channel Number field 1008. The NPCH Access Parameter Update field 1005 includes an NPCH Access Transition Delay field 1009. The Secondary Primary Channel Number field 1008 indicates information capable of identifying the NPCH (i.e., SPCH) for which carrier sensing should be performed when NPCH access is enabled. For example, the channel number of the SPCH can be set in the Secondary Primary Channel Number field 1008.When the communication device 100 is an STA 102, the communication device 100 can acquire the value of the Secondary Primary Channel Number field 1008 to determine the channel on which carrier sensing should be performed when the device performs NPCH access. The method for specifying the SPCH is not limited to the channel number of the SPCH, but may also be, for example, information indicating the relative position of the SPCH on the frequency axis with respect to the PCH. The NPCH Access Transition Delay field 1009 indicates the switching time required to switch the channel on which carrier sensing is performed when the communication device 100 is an AP 101. For example, the NPCH Access Transition Delay field 1009 is configured with 3 bits, and values ​​of 0, 1, 2, 3, 4, and 5 indicate switching times of 0, 16, 32, 64, 128, and 256 μsec, respectively. When the NPCH Access Mode field 1006 is 0, the Secondary Primary Channel Number field 1008 and the NPCH Access Transition Delay field 1009 may be omitted. Also, if any parameter does not need to be updated, the field corresponding to that parameter may be omitted.

[0081] In this way, by using the Action frame, it is possible to timely notify the other communication device that the use of the second communication method will be disabled or enabled. Furthermore, by using the Action frame, it is possible for the AP 101 to notify each STA 102 that the use of the second communication method will be disabled or enabled. For example, when the AP 101 is notified by a specific STA 102 that the frequency bandwidth used for communication will be changed to 20 MHz, the AP 101 can notify this specific STA 102 that the use of the second communication method will be disabled while maintaining communication with other STAs. Furthermore, when the AP 101 is notified by a specific STA 102 that the frequency bandwidth used for communication will be changed to a frequency bandwidth larger than 20 MHz, the AP 101 can notify this specific STA 102 that the use of the second communication method will be enabled. In this case, the AP 101 can individually set parameters to be used for NPCH access between the AP 101 and this specific STA 102 using the Action frame.

[0082] The NPCH Operating Mode Notification frame Action field shown in FIG. 10 and the elements included in this field may be included in a frame other than the Action frame. For example, they may be included in a Beacon frame, a Probe Request frame, or a Probe Response frame. They may also be included in an Association Request frame, an Association Response frame, a Reassociation Request frame, or a Reassociation Response frame. For example, when the NPCH Access Mode field 1006 is transmitted in a Beacon frame, the STA 102 may obtain whether the AP 101 has disabled NPCH access based on the value of this field. Furthermore, the STA 102 may determine that the AP 101 has not disabled NPCH access, for example, when a predetermined field is set to a value other than zero. The predetermined field may be, for example, a field included in the NPCH Access Parameter Update Control field 1007 or the NPCH Access Parameter Update field 1005. Furthermore, the STA 102 may determine that the AP 101 has disabled NPCH access when the values ​​of these fields are set to zero. Note that the method by which the STA 102 determines that the AP 101 has enabled NPCH access is not limited to the above. The STA 102 may determine that the AP 101 has enabled NPCH access based on the value of a field related to NPCH access being set to a value other than zero.

[0083] Furthermore, whether NPCH access is disabled or enabled can be indicated using the MAC header of the frame. For example, information specifying whether NPCH access is disabled or enabled can be included in the HT Control field included in the MAC header. This information can be included in the A-Control subfield included in the HT Control field, or a subfield other than the A-Control subfield can be defined to include this information. When the A-Control subfield includes this information, a value indicating information about NPCH access can be defined in the Control ID subfield included in the A-Control subfield.

[0084] (Variation) When performing multi-link communication with a partner communication device, the communication device 100 may determine whether to disable use of the second communication method for each of the multiple links. For example, the communication device 100 may identify a frequency bandwidth available for communication for each of the multiple links and determine whether each frequency bandwidth is equal to a predetermined value. The communication device 100 may then disable use of the second communication method for the link whose available frequency bandwidth is equal to the predetermined value. For example, assume that the multiple links are configured with one link that communicates at a frequency bandwidth of 20 MHz in the 2.4 GHz band and one link that communicates at a frequency bandwidth of 40 MHz in the 5 GHz band. In this case, the communication device 100 may determine to disable use of the second communication method for the 2.4 GHz band link and to enable use of the second communication method for the 5 GHz band link. When notifying the partner communication device that use of the second communication method for any of the multiple links is to be disabled, the communication device 100 may individually notify the link. For example, when disabling the use of the second communication method for a link in the 2.4 GHz band, the communication device 100 may notify the other communication device of the 2.4 GHz band link. On the other hand, when disabling the use of the second communication method for multiple links, the communication device 100 may notify the other communication device of the 2.4 GHz band link separately for each link. For example, when disabling the use of the second communication method for a link in the 2.4 GHz band and a link in the 5 GHz band, the communication device 100 may notify the other communication device of the 2.4 GHz band link separately for each link. This makes it possible to apply the present technology even when a connection is established separately for each link. Furthermore, the communication device 100 may notify the other communication device of the disablement of the use of the second communication method for two links using either the 2.4 GHz band link or the 5 GHz band link. For example, the communication device 100 may notify the other communication device of the disablement of the use of the second communication method for two links using the 5 GHz band link. This reduces the overhead required for notification, thereby enabling efficient use of wireless resources.

[0085] As described above, according to the present embodiment, the communication device 100 identifies a predetermined frequency bandwidth configured to be used for communication by the communication device itself, and disables communication using the second communication method based on the predetermined frequency bandwidth being a predetermined value. For example, the first communication method is a communication method in which, when the PCH is available, communication is performed using the PCH and one or more NPCHs. The second communication method is a communication method in which, when a first condition is that the PCH is unavailable, communication is performed using an NPCH that satisfies the second condition without using the PCH. With this configuration, the communication device 100 can determine that the second communication method is unavailable based on the frequency bandwidth used for communication and disable use of the second communication method. Furthermore, the communication device 100 can notify the other communication device that use of the second communication method is disabled. This makes it possible to prevent the communication device itself or the other communication device from attempting to use the second communication method when the second communication method is unavailable. Therefore, it is possible to reduce power consumption by suppressing attempts to use the second communication method in each communication device, and to efficiently use frequency resources by avoiding failures in transmission using the second communication method.

[0086] In the present embodiment, communication between the AP 101 and the STA 102 is exemplified, but the present technology can also be applied between multiple STAs. In addition, in the present embodiment, a case where a communication method that does not use a PCH is called NPCH access is exemplified, but the present technology is not limited to this and may be called, for example, Secondary Primary Channel access. In the present embodiment, a case where a channel for determining whether or not to transmit using an NPCH is called SPCH for convenience is exemplified, but the present technology is not limited to this. Among multiple secondary channels, a channel with a high priority for determining whether or not to transmit may be called PSCH (Primary Secondary Channel). Whichever term is used, it means that the channel should be used to determine whether or not to transmit using an NPCH. In addition, the names of the information elements and various fields in the present embodiment may be called by other names.

[0087] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0088] (Summary of the embodiment) At least some of the above-described embodiments can be summarized as follows. (Item 1) A communication device capable of communicating with other communication devices using wireless frames that comply with at least one predetermined standard included in the IEEE 802.11 standard series, the predetermined standard includes provisions for communication using a plurality of communication methods, including a first communication method configured to be able to communicate by bonding a first channel with one or more second channels different from the first channel, the first communication method acquiring a transmission right using the first channel to perform communication, and a second communication method acquiring a transmission right using a third channel included in the second channels to perform communication using at least the third channel when the first channel cannot be used, The communication device means for identifying a predetermined frequency bandwidth that the communication device is configured to use for communication; and a notification means for notifying the other communication device that communication using the second communication method will be disabled based on the predetermined frequency bandwidth being a predetermined value. A communication device comprising: (Item 2) The predetermined value is a value of 20 MHz or less. 2. The communication device according to item 1, (Item 3) The communication device further includes a setting unit for setting the predetermined frequency bandwidth. 3. The communication device according to item 1 or 2. (Item 4) The setting means sets a frequency bandwidth input by a user as the predetermined frequency bandwidth. 4. The communication device according to item 3, (Item 5) The communication device further includes an acquisition means for acquiring, from the other communication device, a frequency bandwidth configured to be used for communication by the other communication device; The setting means sets a frequency bandwidth that is configured to be used by the other communication device for communication as the predetermined frequency bandwidth. 4. The communication device according to item 3, (Item 6) The setting means sets the frequency bandwidth set in the connection established with the other communication device as the predetermined frequency bandwidth. 4. The communication device according to item 3, (Item 7) When the predetermined frequency bandwidth set in the communication device is changed, the notification means When the predetermined frequency bandwidth is no longer a predetermined value, a notification is sent to the other communication device to enable communication using the second communication method; When the predetermined frequency bandwidth reaches a predetermined value, a notification is sent to the other communication device to disable communication using the second communication method. 7. The communication device according to any one of items 3 to 6, (Item 8) The specifying means specifies the specific frequency band as the predetermined frequency bandwidth when the communication device does not have the ability to communicate using a frequency bandwidth other than the specific frequency bandwidth. 8. The communication device according to any one of items 1 to 7, (Item 9) When the communication device performs multi-link communication with the other communication device, the specifying means specifies the predetermined frequency bandwidth for each of a plurality of links constituting a multilink; The notification means notifies the other communication device that communication using the second communication method will be disabled based on the predetermined frequency bandwidth being the predetermined value for each of the plurality of links. 9. The communication device according to any one of items 1 to 8, (Item 10) When disabling communication using the second communication method for any of the plurality of links, the notification means issues a notification that communication using the second communication method will be disabled for that link. 10. The communication device according to item 9, (Item 11) The notification means notifies information that identifies one or more specific links included in the plurality of links for which communication using the second communication method is to be disabled. 10. The communication device according to item 9, (Item 12) The notification means performs the notification using at least one of a Beacon frame, a Probe Response frame, an Association Response frame, a Reassociation Response frame, and an Action frame. 12. The communication device according to any one of items 1 to 11, (Item 13) The notification means performs the notification using at least one of a Probe Request frame, an Association Request frame, a Reassociation Request frame, and an Action frame. 12. The communication device according to any one of items 1 to 11, (Item 14) 1. A communication method executed by a communication device capable of communicating with another communication device using wireless frames conforming to at least one predetermined standard included in the IEEE 802.11 series of standards, comprising: the predetermined standard includes provisions for communication using a plurality of communication methods, including a first communication method configured to be able to communicate by bonding a first channel with one or more second channels different from the first channel, the first communication method acquiring a transmission right using the first channel to perform communication, and a second communication method acquiring a transmission right using a third channel included in the second channels to perform communication using at least the third channel when the first channel cannot be used, The communication method includes: identifying a predetermined frequency bandwidth over which the communication device is configured to communicate; and a step of notifying the other communication device that communication using the second communication method will be disabled based on the predetermined frequency bandwidth being a predetermined value. A communication method comprising: (Item 15) A program for causing a computer to function as each of the means possessed by the communication device according to any one of items 1 to 13.

[0089] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0090] 101: AP, 102: STA, 103: Network, 111: AP, 112: STA, 113: Network

Claims

1. A communication device capable of communicating with other communication devices using wireless frames conforming to at least one predetermined standard included in the IEEE 802.11 standard series, the predetermined standard includes provisions for communication using a plurality of communication methods, including a first communication method configured to be able to communicate by bonding a first channel with one or more second channels different from the first channel, the first communication method acquiring a transmission right using the first channel to perform communication, and a second communication method acquiring a transmission right using a third channel included in the second channels to perform communication using at least the third channel when the first channel cannot be used, The communication device means for identifying a predetermined frequency bandwidth that the communication device is configured to use for communication; and a notification means for notifying the other communication device that communication using the second communication method will be disabled based on the predetermined frequency bandwidth being a predetermined value. A communication device comprising:

2. The predetermined value is a value of 20 MHz or less.

2. The communication device according to claim 1.

3. The communication device further includes a setting unit for setting the predetermined frequency bandwidth.

2. The communication device according to claim 1.

4. The setting means sets a frequency bandwidth input by a user as the predetermined frequency bandwidth.

4. The communication device according to claim 3.

5. The communication device further includes an acquisition means for acquiring, from the other communication device, a frequency bandwidth configured to be used for communication by the other communication device; The setting means sets a frequency bandwidth that is configured to be used by the other communication device for communication as the predetermined frequency bandwidth.

4. The communication device according to claim 3.

6. The setting means sets the frequency bandwidth set in the connection established with the other communication device as the predetermined frequency bandwidth.

4. The communication device according to claim 3.

7. When the predetermined frequency bandwidth set in the communication device is changed, the notification means When the predetermined frequency bandwidth is no longer a predetermined value, a notification is sent to the other communication device to enable communication using the second communication method; When the predetermined frequency bandwidth reaches a predetermined value, a notification is sent to the other communication device to disable communication using the second communication method.

4. The communication device according to claim 3.

8. The specifying means specifies the specific frequency band as the predetermined frequency bandwidth when the communication device does not have the ability to communicate using a frequency bandwidth other than the specific frequency bandwidth.

2. The communication device according to claim 1.

9. When the communication device performs multi-link communication with the other communication device, the specifying means specifies the predetermined frequency bandwidth for each of a plurality of links constituting a multilink; The notification means notifies the other communication device that communication using the second communication method will be disabled based on the predetermined frequency bandwidth being the predetermined value for each of the plurality of links.

2. The communication device according to claim 1.

10. When disabling communication using the second communication method for any of the plurality of links, the notification means issues a notification that communication using the second communication method will be disabled for that link.

10. The communication device according to claim 9.

11. The notification means notifies information specifying one or more specific links included in the plurality of links for which communication using the second communication method is to be disabled.

10. The communication device according to claim 9.

12. The notification means performs the notification using at least one of a Beacon frame, a Probe Response frame, an Association Response frame, a Reassociation Response frame, and an Action frame.

2. The communication device according to claim 1.

13. The notification means performs the notification using at least one of a Probe Request frame, an Association Request frame, a Reassociation Request frame, and an Action frame.

2. The communication device according to claim 1.

14. 1. A communication method performed by a communication device capable of communicating with another communication device using wireless frames conforming to at least one predetermined standard included in the IEEE 802.11 series of standards, comprising: the predetermined standard includes provisions for communication using a plurality of communication methods, including a first communication method configured to be able to communicate by bonding a first channel with one or more second channels different from the first channel, the first communication method acquiring a transmission right using the first channel to perform communication, and a second communication method acquiring a transmission right using a third channel included in the second channels to perform communication using at least the third channel when the first channel cannot be used, The communication method includes: identifying a predetermined frequency bandwidth over which the communication device is configured to communicate; and a notification step of notifying the other communication device that communication using the second communication method will be disabled based on the predetermined frequency bandwidth being a predetermined value. A communication method comprising:

15. A program for causing a computer to function as each of the means included in the communication device according to claim 1.

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