Communication device, communication method, and program

Abstract

Provided is a communication device, wherein with a communication means which performs communication with another communication device by a first channel access method that uses at least a predetermined primary channel in one link and by a second channel access method that does not use the primary channel if the primary channel is in a busy state and uses a non-primary channel different from the primary channel among a plurality of channels included in the link, if the primary channel becomes available in a period in which communication with a first communication device by the second channel access method is being executed, first control for causing the operating state of the communication device for the primary channel to transition to a predetermined state, second control for causing the state of the primary channel to transition to a predetermined state, third control for sending a predetermined signal to the first communication device that is executing communication using the non-primary channel, or fourth control for ending the communication with the first communication device by the second channel access method is executed.

Description

Communication device, communication method, and program

[0001] The present disclosure relates to a data communication technique in a communication device capable of communication using a communication link configured by a plurality of channels.

[0002] In recent years, with the increase in the amount of data being communicated, development of communication technologies such as wireless LANs (Local Area Networks) has been progressing. The Institute of Electrical and Electronic Engineers (IEEE) 802.11 standard series is known as a major communication standard for wireless LANs. The IEEE 802.11 standard series includes IEEE 802.11a / b / g / n / ac / ax / be standards, etc. In order to further improve communication reliability, development of the IEEE 802.11bn standard is underway as a successor to the IEEE 802.11be standard. In the IEEE 802.11 Working Group (WG), which formulates the IEEE 802.11bn standard, the UHR SG will determine the goals and scope of the standard, and the TGbn will specify the detailed technical content to be included in the standard. UHR SG is an abbreviation for Ultra High Reliability Study Group. TGbn is an abbreviation for Task Group bn.

[0003] As one of the candidate technologies to be included in the IEEE 802.11bn standard, a technology for efficiently utilizing frequency resources in a communication method using a communication link configured with multiple channels is being considered. For example, Patent Document 1 describes a technology for performing communication using another channel when a primary channel used to acquire a transmission right cannot be used.

[0004] U.S. Pat. No. 1,169,6353

[0005] The present disclosure provides a technique for more efficiently utilizing frequency resources in a communication system that uses a communication link consisting of multiple channels.

[0006] A communication device according to one aspect of the present disclosure is a communication device that performs communication in accordance with the IEEE 802.11 standard series, and includes: communication means for performing communication with another communication device using a first channel access method that uses at least a predetermined primary channel in one link; and a second channel access method that does not use the primary channel when the primary channel is busy and uses a non-primary channel different from the primary channel among a plurality of channels included in the link; and a communication unit that communicates with the first communication device and the second channel access method. and a control means for executing, when the Primary channel becomes available during a period in which communication is being performed using the second channel access method, a first control for transitioning the operating state of the communication device for the Primary channel to a predetermined state, a second control for transitioning the state of the Primary channel to a predetermined state, a third control for sending a predetermined signal to the first communication device which is performing communication using the Non-Primary channel, or a fourth control for terminating communication with the first communication device using the second channel access method.

[0007] According to the present disclosure, frequency resources can be utilized more efficiently in a communication system that uses a communication link consisting of multiple channels.

[0008] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0009] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments of the present invention, and are used to explain the principles of the present invention together with the description.

[0016] Figure 1 is a diagram showing an example of the configuration of a wireless communication system.

[0017] Figure 2 is a schematic diagram showing an example of a time chart when a communication device transmits data.

[0018] Figure 3 is a schematic diagram showing an example of a time chart when a communication device transmits data.

[0019] Figure 4 is a diagram showing an example of the hardware configuration of a communication device.

[0020] Figure 5 is a diagram showing an example of the functional configuration of a communication device.

[0021] Figure 6 is a diagram showing an example of a time chart when signals are exchanged between a PCH and an NPCH.

[0022] Figure 7 is a diagram showing an example of a flow showing the operation of a communication device when receiving.

[0023] Figure 8 is a diagram showing an example of a time chart when signals are exchanged between a PCH and an NPCH.

[0024] Figure 9 is a diagram showing an example of a flow showing the operation of a communication device when receiving.

[0025] Figure 10 is a diagram showing an example of a time chart when signals are exchanged between a PCH, an NPCH, and other links.

[0026] Figure 11 is a diagram showing an example of a flow showing the operation of a communication device when receiving.

[0027] Figure 12 is a diagram showing an example of a notification signal notifying that a PCH has become available.

[0028] Figure 13 is a diagram showing an example of a notification signal notifying that a PCH has become available.

[0010] 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.

[0011] (System Configuration) FIG. 1 shows an example configuration of a wireless communication system according to this embodiment. The wireless communication system includes, for example, an access point (AP) 101 and stations (STA) 102 and 103. The AP 101, STA 102, and STA 103 are communication devices capable of performing wireless communication in accordance with the IEEE 802.11 standard series. IEEE stands for Institute of Electrical and Electronics Engineers. FIG. 1 shows a configuration in which the STAs 102 and 103 participate in a network 10 established by the AP 101. The network 10 may also be referred to as a Basic Service Set (BSS). While FIG. 1 shows a configuration in which one AP 101 and two STAs 102 and 103 exist, there may be one or more APs and STAs. In addition, at that time, multiple STAs may be connected to one AP, or one STA may be connected to multiple APs. In FIG. 1 , a network 11 configured by AP 111 and STA 112 exists near a network 10 configured by AP 101, STA 102, and STA 103. Like AP 101, STA 102, and STA 103, AP 111 and STA 112 are communication devices capable of performing wireless communication compliant with the IEEE 802.11 standard series. For AP 101, STA 102, and STA 103, network 10 is a BSS to which the respective devices connect, and may be referred to as their own BSS. On the other hand, for AP 101, STA 102, and STA 103, network 11 is a network that may cause interference to their own BSS, and may be referred to as an overlapping BSS (OBSS). In this embodiment, the AP 101, AP 111, STA 102, STA 103, and STA 112 may be collectively referred to as a communication device 100. Furthermore, the AP 101 and AP 111 may be simply referred to as an AP, and the STA 101, STA 102, and STA 103 may be simply referred to as an STA.

[0012] In this embodiment, the communication device 100 is configured to be able to execute a communication method conforming to 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 main features of the IEEE 802.11bn standard are its functions for realizing highly reliable communication, low latency communication, and improved throughput when communication traffic is congested. The wireless frame used in the communication method conforming to this standard may be called a UHR (Ultra High Reliability) PPDU. PPDU is an abbreviation for PLCP Protocol Data Unit, and PLCP is an abbreviation for Physical Layer Convergence Protocol. It should be noted that names such as UHR and IEEE 802.11bn may be changed to other names when the standards are fully established. It should be noted that this specification and the claims attached hereto are applicable to communication devices using all successor standards to IEEE 802.11be. Furthermore, the communication device 100 may be compatible with 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 be compatible with other communication standards, such as Bluetooth (registered trademark), NFC, UWB, ZigBee, MBOA, etc. UWB stands for Ultra Wide Band, and MBOA stands for Multi Band OFDM Alliance. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, etc. The communication device 100 may also be compatible with communication standards such as wired LAN. The AP may be, for example, a wireless LAN router or a personal computer (PC), but is not limited to these. The AP may be an information processing device, such as a wireless chip, capable of performing wireless communication compliant with the IEEE 802.11bn standard, etc.The STA is, for example, but not limited to, a camera, a tablet, a smartphone, a PC, a mobile phone, a video camera, a headset, etc. The STA may be an information processing device such as a wireless chip capable of performing wireless communication compatible with the IEEE 802.11bn standard or the like.

[0013] The communication device 100 may communicate using radio signals in frequency bands such as the 2.4 GHz band, the 3.6 GHz band, the 5 GHz band, the 6 GHz band, and the 45 GHz band and 60 GHz band, which are called millimeter waves. The frequency bands used by the communication device 100 are not limited to these and may be, for example, the Sub 1 GHz band. The communication device 100 may also communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The bandwidths used by the communication device 100 are not limited to these and may be, for example, 240 MHz, 4 MHz, etc. The IEEE 802.11 standard series specifies a frequency channel using a 20 MHz bandwidth as a basic channel in frequency bands such as the 2.4 GHz, 5 GHz, and 6 GHz bands. This standard also defines multiple available channels in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. This standard allows the 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. A channel bundle formed by one or two or more adjacent channels may be referred to as a communication link. That is, a link formed by two channels with a bandwidth of 20 MHz may use a bandwidth of 40 MHz. The IEEE 802.11be standard is expected to specify 320 MHz as the maximum bandwidth available for a single link. Signals transmitted in this bandwidth may be continuous or discontinuous on the frequency axis. The AP and STA may be AP MLDs (Multi-Link Devices) and STA MLDs, respectively, that support Multi-Link, which simultaneously establishes multiple links for communication. Communication between communication devices in which multiple links are simultaneously established can be called multi-link communication.

[0014] 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 device intends to use for transmission. For example, the communication device 100 measures the strength of a signal received on the channel (received signal strength) and determines that a signal is present when the received signal strength exceeds a predetermined threshold (physical carrier sense). 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 sense). For example, the communication device 100 stores the duration indicated by the Duration field included in the received signal as a Network Allocation Vector (NAV) within the device. The communication device 100 may treat the stored NAV as a period during which the device will not transmit a signal. 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 transmission is not possible. The channel state in this case may be referred to as a busy state. On the other hand, a state in which no signal is detected on the channel during carrier sense and no NAV is set may be referred to as an idle state. If the channel is in an idle state, the communication device 100 may determine that transmission is possible.

[0015] For example, when communicating using a link with a bandwidth of 160 MHz, the communication device 100 may determine whether or not to transmit using only the 20 MHz Primary Channel (PCH) included in that link. For example, the IEEE 802.11 series of standards describes that the communication device 100 can start transmission if it determines that transmission is possible as a result of performing carrier sensing on the PCH for a predetermined period of time. 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. In other words, if the communication device 100 determines that the PCH is idle for this predetermined period of time, it acquires the right to transmit using that link. At this time, if a channel other than the PCH was idle during the PIFS period immediately before the start of transmission, the communication device 100 may perform transmission using channel bonding using the idle channel and the PCH. PIFS is an abbreviation for Priority Interframe Space. Furthermore, when the communication device 100 determines that transmission is not possible as a result of carrier sensing on the PCH, it may postpone transmission even if other channels included in the same link are idle. Each channel other than the PCH that constitutes a single link may be called a secondary channel (SCH). A secondary channel may also be called a non-primary channel (NPCH).

[0016] 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) located at a frequency close to the received channel, the received signal may not be properly received. For example, assume that the communication device 100 is capable of simultaneously performing transmission and reception processes using different channels. If the communication device 100 receives a signal on a certain channel and then transmits on an adjacent channel, the power of the transmitted signal will leak into the channel of the received signal, causing interference with the received signal. Generally, the power of such transmitted signal leakage is much greater than the received power of the received signal, so the received signal will not be properly received. To avoid this situation, the IEEE 802.11 standard series provides a mechanism to prevent other communication devices from transmitting signals to a communication device using a channel adjacent to the PCH while 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 will not transmit, even if the other channel is idle. As a result, while a communication device is transmitting a signal and a PCH is in use, other communication devices will not transmit signals using a channel adjacent to the PCH, preventing the communication device from receiving a signal on that adjacent channel, thereby eliminating the problem of interference caused by power leakage between channels.

[0017] However, not using other idle channels (NPCHs) based on the PCH being busy can hinder efficient use of frequency resources across 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 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 also shows another example of a time chart when STA 102 transmits data to AP 101. In Figure 2B, while STA 102 is performing carrier sensing on the PCH, the PCH is being used by another network (e.g., network 11 in Figure 1) located geographically near STA 102. In this case, the PCH is determined to be busy by the carrier sense performed by STA 102, and therefore, even if the seven NPCHs other than the PCH are idle, STA 102 is not permitted to communicate with AP 101 using the NPCH. However, because AP 101 is not transmitting at this time, even if STA 102 transmits to AP 101 using the NPCH, AP 101 can properly receive the signal transmitted by STA 102. In this way, if the PCH with a bandwidth of, for example, 20 MHz is used by another network, the remaining 140 MHz of idle NPCHs are not utilized, resulting in inefficient use of frequency resources.

[0018] In consideration of these circumstances, this embodiment provides a function for performing communication between communication devices using NPCHs included in the same link as the PCH, without using the PCH, when the PCH is being used by another communication device. 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 NPCHs included in the same link as the PCH. When the communication device 100 determines that the PCH is being used by another communication device, it then determines whether transmission is possible on the SPCH. When the communication device 100 determines that transmission is possible on the SPCH, it performs transmission using one or more NPCHs including the SPCH. In this embodiment, a communication method for performing transmission using one or more channels including the SPCH without using the PCH is called NPCH access (Non-Primary Channel Access, NPCA). This communication method may be called by other names, for example, SCA (Secondary Channel Access).

[0019] In this embodiment, the communication device 100 communicates using a first communication method using one or more channels including a PCH and a second communication method (NPCH access) using one or more NPCHs not including a PCH. For example, the communication device 100 has the function of executing both the first communication method and the second communication method, and may communicate using the first communication method when a PCH is available and may communicate using the second communication method when a PCH is unavailable. A case in which a PCH is unavailable occurs, for example, when a NAV is set in the communication device 100 due to another communication device starting communication on the PCH. Here, the NPCH access may be set to end within the NAV period set on the PCH. Alternatively, the NPCH access may be permitted only if it ends within the NAV period set on the PCH. If the NPCH is busy when the PCH changes from a busy state to an idle state, the next communication may be performed using only the PCH without using the NPCH. Furthermore, the PCH may be busy when the NPCH changes from a busy state to an idle state. In this way, if the PCH and the NPCH are used independently, frequency resources may not be used efficiently. To avoid this situation, the communication device 100 may control NPCH access so that NPCH access is completed within the period of the NAV set for the PCH. On the other hand, even if NPCH access is controlled so that it is completed within the period of the NAV set for the PCH, the NAV set for the PCH may end before the completion of NPCH access. For example, the NAV set in the communication device 100 may be terminated (canceled) by a CF (Contention Free)-END frame or the like. By canceling the NAV set for the PCH, the communication device 100 becomes able to use the PCH. As a result, for example, when the AP 101 and the STA 102 are communicating via NPCH access, the STA 103 may transmit to the AP 101 using the PCH. On the other hand, if the AP 101 is not performing a receiving operation on the PCH while performing NPCH access, the AP 101 may not receive the signal transmitted by the STA 103 .Furthermore, as described above, when the PCH and the NPCH are used independently, there is a possibility that frequency resources will not be used efficiently. In this embodiment, a technique is provided in which the communication device 100 controls communication using the PCH when the NAV set for the PCH ends earlier than the initial setting in a situation in which NPCH access is being performed between the AP and the STA.

[0020] 3 shows an example of the hardware configuration of the communication device 100 (AP and STA) according to 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.

[0021] The storage unit 301 is configured with one or more memories including ROM, RAM, etc., and may store various information such as control programs for each functional unit constituting the communication device 100 to perform various operations, and parameters for communication. ROM and RAM stand for Read Only Memory and Random Access Memory, respectively. The storage unit 301 may be configured to include, in addition to memories such as ROM and RAM, 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.

[0022] The control unit 302 is configured with one or more processors including, for example, a CPU, an MPU, etc., and controls the entire communication device 100 by executing a control program stored in the storage unit 301. The control unit 302 may control the entire communication device 100 in cooperation with the control program stored in the storage unit 301 and an OS (Operating System). The CPU and MPU are abbreviations for Central Processing Unit and Micro Processing Unit, respectively. When 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.

[0023] The control unit 302 also controls the functional unit 303 to perform predetermined processes such as communication, image capture, printing, and projection. The functional unit 303 is hardware that enables the communication device 100 to perform the predetermined processes described above. For example, if the device is a camera, the functional unit 303 is an image capture unit that performs image capture processing. For example, if the device is a printer, the functional unit 303 is a print unit that performs print processing. For example, if the device is a projector, the functional unit 303 is a projection unit that performs projection processing.

[0024] The input unit 304 receives various operations from the user. The output unit 305 outputs various types of information to the user via a monitor screen or a speaker. The output from the output unit 305 may be a display on the monitor screen, an audio output from a speaker, a vibration output, or the like. The input unit 304 and the output unit 305 may both be implemented as a single module, such as a touch panel. The input unit 304 and the output unit 305 may be integrated into the communication device 100 or may be separate devices.

[0025] The communication unit 306 controls 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. The communication unit 306 controls the antenna 307 to transmit and receive signals for wireless communication generated by the control unit 302. The communication unit 306 is a so-called wireless chip and may itself include one or more processors and memories. Note that if the communication device 100 supports other wireless communication standards, such as the NFC standard or 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, if the communication device 100 can perform wireless communication compliant with multiple communication standards, the communication device 100 may be configured to have separate communication units and antennas corresponding to each communication standard. The communication device 100 communicates data with a counterpart communication device via the communication unit 306. 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 include a communication unit 306 for communication using the PCH and a communication unit 306 for NPCH access. The communication unit 100 may also include a primary communication unit 306 used for communication with other communication devices and a secondary communication unit 306 used to determine whether the PCH has become available while NPCH access is being performed. For example, the secondary communication unit 306 may be a simple circuit having only the functions necessary to determine whether the PCH has become available. When the communication device 100 has multiple communication units 306, some of the communication units 306 may be used for NPCH access, and the other communication units 306 may be configured to communicate using the PCH. In this case, while NPCH access is not being performed, all of the communication units 306 can be used for communication using the PCH. The communication unit 100 may use the multiple communication units 306 by switching between their roles and uses.For example, the communication unit 306 used for communication using the PCH in the first period may be used for communication using the NPCH access in the second period. Note that the AP 101 may have a circuit that performs reception processing on signals received on the PCH and NPCH channels in parallel.

[0026] Antenna 307 is an antenna capable of communication in, for example, the 2.4 GHz band, the 5 GHz band, the 6 GHz band, millimeter waves, etc. Although Fig. 3 shows a configuration in which communication device 100 has two antennas 307, communication device 100 may have one or three or more antennas, or may have one or more antennas for each frequency band that the device can use. Furthermore, if communication device 100 has multiple antennas, communication device 100 may have a communication unit 306 for each antenna.

[0027] (Functional Configuration) FIG. 4 shows an example of the functional configuration of the communication device 100. The functional configuration in this embodiment is, for example, an example of a functional configuration realized by one or more processors executing programs stored in one or more memories. The communication device 100 includes a frame analysis unit 401, a NAV detection unit 402, a wireless communication control unit 403, an NPCH access control unit 404, a PCH communication control unit 405, and a frame generation unit 406. However, this is just an example, and dedicated hardware may be provided to implement each function. Note that the configuration shown in FIG. 4 is just an example, and the AP may include configurations other than these. Furthermore, two or more functional blocks in FIG. 4 may be implemented as a single functional block, or one functional block may be divided into two or more functional blocks.

[0028] The frame analysis unit 401 analyzes a signal (frame) received by the communication unit 306 via the antenna 307. For example, when the frame analysis unit 401 receives a frame on a channel, it extracts the Duration field included in the frame and notifies the NAV detection unit 402 of the extracted Duration field. Furthermore, when the frame analysis unit 401 receives a frame addressed to the device itself, it extracts data included in the frame and passes the extracted data to a higher layer. When the frame analysis unit 401 receives a frame that cancels the NAV set in the PCH, it notifies the NAV detection unit 402 of this. In this embodiment, a signal that cancels the NAV set in the channel is also referred to as a completion signal. When the communication device 100 is performing NPCH access and receives a frame notifying that the PCH has become available, the frame analysis unit 401 notifies the NPCH access control unit 404 of this. When the communication device 100 is performing NPCH access and receives a frame instructing the termination of NPCH access, the frame analysis unit 401 notifies the NPCH access control unit 404. The frame notifying that the PCH has become available or the frame instructing the termination of NPCH access may be received via a link other than the link performing NPCH access. Furthermore, the notification that the PCH has become available or the instruction to terminate NPCH access may be included in a response to the frame transmitted via NPCH access.

[0029] The NAV detection unit 402 sets or updates the NAV for the PCH or SPCH based on the Duration notified by the frame analysis unit 401 or a notification of cancellation of the set NAV. For example, when the NAV detection unit 402 acquires Duration information from the frame analysis unit 401, it sets the NAV for the target channel. On the other hand, when the NAV detection unit 402 receives a notification of NAV cancellation from the frame analysis unit 401, it resets (sets to zero) the NAV set for the target channel. Furthermore, when a NAV is set for the PCH, the NAV detection unit 402 determines whether the PCH has become available. When the PCH has become available, the NAV detection unit 402 notifies the PCH communication control unit 405. The NAV detection unit 402 can determine that the PCH has become available based on receiving a completion signal on the PCH from the frame analysis unit 401.

[0030] The wireless communication control unit 403 performs transmission processing for each frame generated by the frame control unit 406. The wireless communication control unit 403 also notifies the frame analysis unit 401 of frames received via the antenna 307. For example, the wireless communication control unit 403 may transmit or receive data frames using either the first communication method or the second communication method. As an example, the wireless communication control unit 403 performs carrier sensing of the PCH when transmitting a data frame. If a signal is detected on the PCH or if the NAV detection unit 402 sets a NAV, the wireless communication control unit 403 may perform carrier sensing of the SPCH. For example, if the wireless communication control unit 403 does not detect a signal on the SPCH and the NAV detection unit 402 does not set a NAV on the SPCH, the wireless communication control unit 403 transmits the data frame using one or more NPCHs, including the SPCH. If the communication device 100 includes multiple communication units 306, the wireless communication control unit 403 performs communication using each of the communication units 306. Furthermore, when the communication device 100 has established multiple links with other communication devices, the wireless communication control unit 403 executes communication using each link.

[0031] The NPCH access control unit 404 executes settings and control for performing NPCH access. For example, when the communication device 100 is performing NPCH access and the NPCH access control unit 404 is notified by the frame analysis unit 401 that the PCH has become available, the NPCH access control unit 404 determines whether to terminate the NPCH access. If it is determined that the NPCH access should be terminated, the NPCH access control unit 404 instructs the frame generation unit 406 to generate a signal for canceling the NAV set in the NPCH. Furthermore, when the NPCH access control unit 404 receives an instruction to terminate the NPCH access from the frame analysis unit 401, the NPCH access control unit 404 instructs the frame generation unit 406 to generate a completion signal for canceling the NAV set in the NPCH in accordance with this instruction.

[0032] When the PCH communication control unit 405 is notified by the NAV detection unit 402 that the PCH has become available, the PCH communication control unit 405 performs control for communication using the PCH. The control for communication using the PCH performed by the PCH communication control unit 405 will be described in detail below. The PCH communication control unit 405 can control each functional unit, including the wireless communication control unit 403, for communication using the PCH. The frame generation unit 406 generates frames used when the communication device 100 communicates with a partner communication device. The frame generation unit 406 generates frames including, for example, a reservation signal for reserving a channel, a notification that the PCH has become available, a completion signal for canceling the NAV set for the channel, and the like, and notifies the wireless communication control unit 403 of the frames.

[0033] (Examples of Processing Executed in Communication Device) In the following, several examples of the flow of processing executed by the communication device 100 in this embodiment will be described. In these processing examples, an example will be described in which the AP 101 receives a signal transmitted by NPCH access from the STA 102 when NAV is set in the PCH. Note that although the following processing examples will be described as the operation of the AP 101, they can also be applied to the operation of the STA 102.

[0034] [Processing Example 1] Figure 5 shows an example of a time chart relating to signals exchanged on the PCH and NPCH in this processing example. First, assume that at time t1, AP 111 belonging to the OBSS transmits a data frame 501 addressed to STA 112 on the PCH. AP 101 and STA 102 set NAV 503 on the PCH based on the value of the Duration field included in the received data frame 501, etc. STA 112 transmits ACK 502 upon successfully receiving data frame 501. Meanwhile, when data addressed to AP 101 is accumulated in the transmission buffer of STA 102, STA 102 initiates a channel access procedure for transmitting this data. That is, STA 102 performs carrier sensing on the PCH, and upon confirming that the PCH is in an idle state, initiates transmission of this data. Here, since NAV 503 is set on the PCH, STA 102 performs carrier sensing on the SPCH according to the NPCH access procedure. Based on the fact that the SPCH has been idle for a certain period of time including the backoff counter, the STA 102 starts transmitting a data frame 504 addressed to the AP 101 at time t2. At this time, the STA 102 may perform transmission using one or more NPCHs, including the idle SPCH. Furthermore, when transmitting the data frame 504, the STA 102 may acquire a transmission opportunity (TXOP) on the channel used for transmission. The TXOP is a period during which a communication device that has acquired a transmission right for a channel occupies that channel based on that transmission right. For example, the STA 102 may acquire a TXOP that includes the time required to transmit two pieces of data 504 and 506 to the AP 101 and the time required to receive ACKs 505 and 507, which are acknowledgements for each piece of data, from the AP 101. The TXOP may be indicated by a Duration field included in the header of the data frame 504, or may be indicated through an exchange of RTS and CTS frames (RTS / CTS exchange) not shown.In this case, information indicating the TXOP may be stored in the Duration field of each of the RTS frame and CTS frame transmitted prior to the data frame 504. Note that RTS and CTS are abbreviations for Request To Send and Clear To Send, respectively. The communication device 100 that receives the data frame 504 or the like sets a NAV 508 for a period corresponding to the TXOP. As a result, the communication device that acquires the transmission right for the channel may occupy the channel for the TXOP period. Note that the STA 102 may set a TXOP period that is shorter than the period until the NAV 503 set in the PCH expires. As a result, if the NPCH is available when the NAV 503 in the PCH expires, channel bonding using the PCH and the NPCH can be performed at the next transmission opportunity. Note that this example illustrates a case where the STA 102 acquires a TXOP on the NPCH, but the present invention is not limited to this. If the AP 101 has data to transmit, it can also attempt to acquire a TXOP on the NPCH. If the AP 101 wins channel access on the NPCH, the AP 101 can transmit data addressed to a STA on the NPCH. Returning to the description of FIG. 5 , at time t3, a CF-END frame 509 is transmitted on the PCH as a completion signal for canceling the NAV 503 set on the PCH. The CF-END frame 509 can be transmitted by the AP 111. As a result, a new signal can be transmitted on the PCH based on the PCH becoming available. In the example of FIG. 5 , at time t4, the STA 103 starts transmitting a data frame 510 addressed to the AP 101 using the PCH. For example, if STA103 is a communication device that communicates using only the PCH, STA103 may transmit a data frame 510 to AP102 using an idle PCH regardless of whether AP102 is communicating via NPCH access.

[0035] In this processing example, if the PCH becomes available while the AP 101 is receiving a data frame 504 on the NPCH, the AP 101 performs an operation to receive a signal transmitted on the PCH. For example, the AP 101 first monitors to determine whether the PCH has become available, in parallel with communication via the NPCH access. As an example, the AP 101 may determine that the PCH has become available by detecting a completion signal on the PCH. Once the AP 101 determines that the PCH has become available, it begins receiving operations on the PCH in preparation for receiving a signal that may be transmitted on the PCH. Then, if the AP 101 detects a new signal on the PCH, it begins receiving processing for that signal. If the signal received on the PCH is a signal addressed to the AP 101 (e.g., data frame 510), the AP 101 may perform receiving processing on the signal and forward the acquired data to a higher layer. Furthermore, if the signal received on the PCH is not addressed to the AP 101, the AP 101 may abort the receiving process or discard the received signal. In this way, by performing receiving operations on the PCH based on the detection that the PCH has become available while communicating via NPCH access, AP101 can successfully receive signals transmitted on the PCH.

[0036] FIG. 6 shows an example of the flow of the reception operation performed by the AP 101 in the time chart of FIG. 5 . This reception operation is applicable not only to the AP 101 but also to communication devices 100 including the STA 102, and therefore will be described below as the operation of the communication device 100. First, the communication device 100 detects a signal on the PCH. When a signal is received on the PCH (YES in S601), the communication device 100 determines whether the signal is from its own BSS (S602). For example, the communication device 100 may determine whether the signal is from its own BSS or from an OBSS based on whether the BSS Color field included in the received signal matches the BSS Color of the own BSS. The communication device 100 may also determine whether the signal is from its own BSS or from an OBSS based on whether the values ​​stored in the destination field, source field, etc. included in the received signal match the parameters of the own BSS. If the received signal is a signal from the communication device 100's own BSS, the communication device 100 performs normal reception processing (S603). For example, normal reception processing involves extracting data from the signal and forwarding it to a higher layer if the signal is addressed to the communication device based on the destination field of the received signal. If the signal is not addressed to the communication device, the communication device 100 discards the signal. On the other hand, if the received signal is not a signal from the communication device's own BSS (NO in S602), the communication device 100 sets a NAV for the PCH based on the value of the Duration field included in the received signal (S604). Next, the communication device 100 performs signal detection on the SPCH. If the NAV set for the PCH expires before the communication device 100 detects a signal on the SPCH (NO in S605 and YES in S606), the communication device 100 returns to S601 and continues processing.

[0037] On the other hand, if a signal transmitted using one or more NPCHs including the SPCH is detected on the SPCH (YES in S605), the communication device 100 performs reception processing for the signal. Furthermore, while performing this reception processing, the communication device 100 also performs monitoring of the PCH in parallel. Here, if the PCH becomes available before the reception processing is completed (YES in S608), the communication device 100 performs control for communication using the PCH (S609). Control for communication using the PCH may include, for example, receiving a new signal on the PCH or detecting a signal for receiving a new signal. When the communication device 100 receives a new signal on the PCH, it may perform reception processing for the received signal, similar to the processing in S601 to S604. Note that, during the period when the communication device 100 sets the NAV on the PCH, it may operate only the minimum functions necessary for PCH communication and operate other functions in a power-saving manner. Furthermore, when the communication device 100 detects that the PCH has become available, it may transition those functions from power-saving operation to normal reception operation. Power-saving operation during the NAV period can reduce power consumption. If the signal received in S605 is not an OBSS signal or is not addressed to the communication device 100, the communication device 100 may set a NAV for the SPCH based on the value of the Duration field included in the signal and wait for the reception process to expire. When the communication device 100 completes the reception process for the signal via NPCH access (NO in S608 and YES in S607), it continues carrier sensing for the SPCH until the NAV set for the PCH expires (S606). When the NAV for the PCH expires, the communication device 100 returns to S601 and continues processing. Although not shown in FIG. 6 , as described above, the communication device 100 may also attempt to acquire a TXOP on the NPCH at the timing after the NAV is set on the PCH. When the communication device 100 wins the TXOP of the NPCH, it may execute data transmission processing using the NPCH instead of the processing of S605-S606. In this case, the communication device 100 executes this transmission processing while concurrently monitoring the PCH.

[0038] In the above, an example has been described in which the communication device 100 executes reception processing on the PCH as control for communication using the PCH when the PCH becomes available. However, the control performed by the communication device 100 for communication using the PCH is not limited to this. For example, the communication device 100 may execute transmission processing on the PCH. For example, at time t4 in FIG. 5 , the AP 101 may transmit a signal addressed to the STA 103 on the PCH. At this time, the transmission power of the PCH may cause interference with the NPCH. On the other hand, when there are multiple NPCHs, the NPCH on which the AP 101 is receiving a data frame from the STA 102 may be separated from the PCH on the frequency axis. For example, if the NPCH on which the AP 101 is receiving a signal from the STA 102 is separated from the PCH on the frequency axis and the interference power caused on the NPCH by the transmission on the PCH is smaller than a threshold, the AP 101 may determine to execute transmission on the PCH.

[0039] 5 shows an example in which AP 101 receives signals on the PCH and NPCH, but if AP 101 is transmitting a signal addressed to STA 102 via NPCH access, AP 101 may transmit a signal addressed to STA 103 at time t4. At this time, AP 101 may adjust the length of the data frame and the transmission period so that the downlink signal transmitted to STA 102 or STA 103 and the uplink signal received from STA 102 or STA 103 do not overlap on the time axis. For example, AP 101 may insert padding or the like into the signal transmitted to STA 103 so that the signal transmitted to STA 102 and the ACK received from STA 103 do not overlap on the time axis, thereby adjusting the signals transmitted to each STA to complete transmission at the same time. By adjusting the end times of communication using the PCH and NPCH access so that they coincide with each other, AP 101 can avoid mutual interference between these communications and enable channel bonding using the PCH and NPCH at the next transmission opportunity.

[0040] As described above, in this processing example, the communication device 100 performing communication via NPCH access determines whether the PCH has become available in parallel, and if the PCH becomes available during communication via NPCH access, performs control for communication using the PCH. For example, as control for communication using the PCH, by starting a reception operation on the PCH, it becomes possible to receive a new signal addressed to the device on the PCH. Furthermore, when the communication device 100 is performing transmission via NPCH access, by performing transmission on the PCH as control for communication using the PCH, it is possible to avoid transmitting a signal addressed to the device using the PCH. Furthermore, by the communication device 100 adjusting the end times of communication using the PCH and communication using NPCH access, it becomes possible to perform channel bonding using both the PCH and the NPCH at the next transmission opportunity.

[0041] [Processing Example 2] In Processing Example 1, the operation of AP 101 was described using an example in which AP 101, communicating via NPCH access, receives or transmits data on the PCH when it determines that the PCH is available. In this processing example, the operation of AP 101 is described using an example in which AP 101, communicating via NPCH access, transmits a signal that inhibits other communication devices from transmitting on the PCH when it determines that the PCH is available. Figure 7 shows an example of a time chart related to signals exchanged on the PCH and NPCH in this processing example. Operations similar to those in Figure 5 are assigned the same reference numerals and will not be described again. First, at time t1, AP 111 transmits a data frame 501 addressed to STA 112 on the PCH, and AP 101 and STA 102, receiving this, set NAV 503 on the PCH. At time t2, STA 102 begins transmitting a data frame 504 addressed to AP 101 using NPCH access. At time t3, a CF-END frame 509 is transmitted to cancel the NAV 503 set for the PCH. This creates the possibility that a new signal addressed to AP 101 will be transmitted on the PCH, based on the PCH becoming available. When AP 101 determines that the PCH has become available, it transmits a signal to suppress transmission on the PCH at time t4. This allows AP 101 to avoid transmitting signals addressed to itself using the PCH. For example, AP 101 transmits a reservation signal 701 to reserve a channel on the PCH to suppress transmission on the PCH. As an example, the signal reserving the channel may be a CTS-to-Self frame. Similar to an RTS / CTS exchange, the CTS-to-Self frame is used as a frame to protect subsequent signals from interference. In this processing example, the CTS-to-Self frame may be used to prohibit other communication devices from transmitting on the PCH. Furthermore, compared to RTS / CTS exchange, when a CTS-to-Self frame is used, channel reservation is completed by transmitting one frame, so reception processing at AP 101 is not required.The communication devices 100 (STA 103, AP 111, STA 112, etc.) that receive a reservation signal including a channel reservation period set NAV 702 on the PCH. When NAV 702 expires, each communication device 100 determines that the PCH is available for use and initiates a channel access procedure. For example, at time t5, STA 103 acquires the transmission right and transmits a data frame 703 addressed to AP 101 by channel bonding using the PCH and NPCH.

[0042] FIG. 8 shows the operational flow executed by the AP 101 in the time chart of FIG. 7 . As with FIG. 6 , this is applicable to a communication device 100 including a STA 102, and therefore the following description will be given as the operation of the communication device 100. Furthermore, the same reference numerals are used for operations similar to those in FIG. 6 , and their description will be omitted. First, the communication device 100 performs carrier sensing on the PCH according to the procedure of S601 to S604. If a NAV is set by an OBSS signal on the PCH (NO in S602), the communication device 100 continues with carrier sensing on the SPCH. If a signal is detected on the SPCH (YES in S605), the communication device 100 performs reception processing for this signal. Furthermore, while performing this reception processing, the communication device 100 also monitors the PCH in parallel. If the NAV set on the PCH ends before the reception processing is completed (YES in S608), the communication device 100 transmits a signal to suppress PCH transmission (S801). The communication device 100 may determine the period during which PCH transmission is suppressed based on the TXOP period in NPCH access and suppress PCH transmission for that period. For example, the communication device 100 may set the value of the Duration field included in the CTS-to-Self frame so that the end of the period during which PCH transmission is suppressed coincides with the expiration of the TXOP period in NPCH access. By aligning the end of the period during which PCH transmission is suppressed with the expiration of the TXOP period in NPCH access, the possibility of performing channel bonding using both the PCH and the NPCH at the next transmission opportunity increases. Note that the communication device 100 may set the period during which PCH transmission is suppressed to be longer than the expiration of the TXOP period in NPCH access, taking into account the time it takes for the AP 101, STA 102, etc. to switch from communication using NPCH access to communication using PCH. When a certain period of time is required for the communication device 100 to switch the communication method used for communication, it is possible to ensure that the communication device that performed the NPCH access and other communication devices can access the channel fairly.In this way, the end of the period during which transmission on the PCH is suppressed and the expiration of the TXOP period for NPCH access do not necessarily have to be simultaneous, and there may be a certain difference within a range that does not hinder channel bonding using both the PCH and NPCH at the next transmission opportunity. When the communication device 100 completes the signal reception process via NPCH access (NO in S608, YES in S607), it continues carrier sensing of the SPCH until the NAV of the PCH expires (S606). When the NAV of the PCH expires, the communication device 100 returns to S601 and continues processing.

[0043] In the above, an example was described in which communication device 100 transmits a CTS-to-Self frame on the PCH when the PCH becomes available. However, the signal for suppressing transmission on the PCH is not limited to a CTS-to-Self frame. AP 101 may perform an RTS / CTS exchange on the PCH. For example, AP 101 may perform an RTS / CTS exchange on the PCH with STA 102 communicating on the NPCH. AP 101 may also perform an RTS / CTS exchange with other STAs connected to the AP 101. RTS / CTS exchange enables suppression of PCH transmissions over a wider geographical area than when a CTS-to-Self frame is used. AP 101 may also determine whether to transmit a CTS-to-Self frame or the like based on interference with NPCH access caused by the transmission power on the PCH. For example, AP 101 may determine to transmit a CTS-to-Self frame or the like on the PCH when the interference power occurring on the NPCH when transmitting on the PCH is smaller than a threshold. On the other hand, if the interference power occurring on the NPCH when transmitting on the PCH is greater than a threshold, AP 101 may initiate an operation to receive a new signal on the PCH without transmitting a CTS-to-Self frame. This makes it possible to receive signals addressed to the device transmitted on the PCH even if it is not possible to suppress transmissions from other communication devices on the PCH. Note that while FIG. 7 illustrates an example in which AP 101 receives a signal, if AP 101 is transmitting a signal to STA 102 via NPCH access, the impact of interference on the NPCH is small even if AP 101 transmits a signal on the PCH during that transmission. Therefore, if the AP 101 determines that the PCH has become available while transmitting a signal via the NPCH access, the AP 101 can transmit a CTS-to-Self frame to the PCH regardless of the magnitude of interference between the NPCH and the PCH. That is, the AP 101 can determine whether the AP 101 is transmitting or receiving using the NPCH access, and can transmit a CTS-to-Self frame to the PCH based on the result.

[0044] As described above, in this processing example, the communication device 100 communicating via NPCH access concurrently determines whether the PCH is available, and if the PCH is available, suppresses signal transmission by other communication devices on the PCH. This, for example, can prevent signals addressed to the communication device communicating via NPCH access from being transmitted on the PCH. Furthermore, by aligning the end of the period during which transmission on the PCH is suppressed with the end of communication via NPCH access, the possibility of performing channel bonding using both the PCH and the NPCH at the next transmission opportunity increases, thereby enabling efficient use of frequency resources.

[0045] [Processing Example 3] In this processing example, the operation of AP 101 will be described using an example in which AP 101, communicating via NPCH access, performs control to terminate NPCH access when it determines that the PCH has become available. Figure 9 shows an example of a time chart relating to signals exchanged in the PCH, NPCH, and other links in this processing example. Operations similar to those in Figure 5 are assigned the same reference numerals and will not be described again. At time t3, AP 101 receives a CF-END frame 509 on the PCH, thereby determining that the PCH has become available. Then, at time t4, AP 101 transmits a notification signal 901 to STA 102, which is transmitting via NPCH access, indicating that the PCH has become available. For example, if AP 101 and STA 102 are communicating via a multi-link, AP 101 may transmit the notification signal 901 using a link other than the link used for NPCH access communication. Upon receiving the notification signal 901, the STA 102 transmits a CF-END frame 902 that cancels the NAV 508 set on the NPCH without transmitting the data frame that was scheduled to be transmitted (for example, data frame 506 in FIGS. 5 and 7). This makes the NPCH available for use. For example, if data addressed to the AP 101 is accumulated in the transmission buffer of the STA 103 at time t6, the STA 103 performs carrier sensing on the PCH and transmits a data frame 903 by channel bonding using the PCH and NPCH.

[0046] FIG. 10 shows the operational flow executed by the AP 101 in the time chart of FIG. 9 . Operations similar to those in FIG. 6 are assigned the same reference numerals and will not be described again. The following description focuses on the operation of the AP 101, but this operational flow is also applicable to a communication device 100 including a STA 102. First, the AP 101 performs carrier sensing on the PCH according to the procedures of S601 to S604. If a NAV is set on the PCH based on an OBSS signal (NO in S602), the AP 101 then performs carrier sensing on the SPCH. If the AP 101 detects a signal on the SPCH (YES in S605), the AP 101 performs reception processing for this signal. While performing this reception processing, the AP 101 also monitors the PCH in parallel. If the NAV set on the PCH ends before the reception processing is completed (YES in S608), the AP 101 transmits a notification signal indicating that the PCH is available (S1001). The AP 101 may transmit a signal instructing the termination of transmission on the NPCH instead of a notification signal indicating that the PCH is available. When the STA 102 receives the notification signal indicating that the PCH is available, the STA 102 may determine whether to terminate the NPCH access based on the type of data being transmitted via the NPCH access, etc. For example, if the data being transmitted is data requiring a delay, the STA 102 may continue the NPCH access as is. On the other hand, if the STA 102 is instructed to terminate transmission on the NPCH, the STA 102 may terminate the NPCH access in accordance with the instruction. When the AP 101 completes the signal reception process via the NPCH access (NO in S608, YES in S607), it continues carrier sensing on the SPCH until the NAV of the PCH expires (S606). When the NAV of the PCH expires, the AP 101 returns to S601 and continues processing.

[0047] FIG. 11 shows an example of a notification signal indicating that the communication device 100 has become able to use the PCH. FIG. 11(A) shows an example of a notification signal when notification is made using a control frame. The control frame 1100 in FIG. 11(A) may be called an Extended CF-END frame. Note that the control frame 1100 may be called by another name. The control frame 1100 includes a Frame Control field 1101, a Duration field 1102, an RA field 1103, a BSSID field 1104, and a Link ID field 1105. Note that RA is an abbreviation for Receiver Address. The Frame Control field 1101 includes information related to frame control. For example, the Frame Control field 1101 includes information such as the frame type and subtype. As an example, in the case of an Extended CF-END frame, the frame type may be Control and the subtype may be Extended CF-END. The Duration field 1102 indicates, for example, an estimate of the time required to transmit this frame and the time required for the response and frame interval. The RA field 1103 indicates address information of the communication device 1103 that should receive this frame. For example, the RA field 1103 may store the address of a communication device with which the communication device 100 transmitting this frame is communicating via NPCH access on another link. The BSSID field 1104 indicates the identifier of the BSS to which the communication device 100 transmitting this frame belongs, or the address of the communication device 100 transmitting this frame. The Link ID field 1105 indicates information that can identify the link in which the PCH has transitioned from a busy state to an available state. The communication device 100 that receives the control frame 1100 knows that a PCH has become available on one of the links because the Frame Control field 1101 indicates that the control frame 1100 is an Extended CF-END frame. The communication device 100 also knows on which link a PCH has become available based on the Link ID field 1105.

[0048] FIG. 11(B) shows an example of a notification signal when notification is performed using an Action frame including a predetermined Action field. The Action field 1110 in FIG. 11(B) may be called a CF-END Notification Action field. Note that the Action field 1110 may be called by another name. The Action field 1110 includes a Category field 1111, a Protected UHR Action field 1112, and a Link ID field 1105. The Category field 1111 indicates the category of this Action field. For example, an identification number corresponding to Protected UHR is stored in the Category field 1111. The Protected UHR Action field 1112 indicates an identifier of this Action field in the Protected UHR category. For example, the Protected UHR Action field 1112 stores an identification number indicating the CF-END Notification Action field. As in FIG. 11A, the Link ID field 1105 indicates information that can identify the link on which the PCH has transitioned from a busy state to an available state. The communication device 100 recognizes that the PCH has become available on one of the links because the Protected UHR Action field 1112 is a CF-END Notification Action field. Furthermore, the communication device 100 uses the Link ID field 1105 to know on which link the PCH has become available.

[0049] If the link on which the PCH has become available matches the link on which the communication device 100 is executing NPCH access, the communication device 100 determines whether to terminate this NPCH access. Note that the control frame 1100 or the Action field 1110 may be transmitted to instruct the communication device 100 to terminate the NPCH access on the link indicated by the Link ID 1105. In this case, the communication device 100 that receives the control frame 1100 or the Action field 1110 terminates the NPCH access in accordance with this instruction.

[0050] In the above example, when the PCH becomes available, the AP 101 notifies the STA 102 using another link. However, the method by which the AP 101 notifies or instructs the STA 102 is not limited to this. For example, the AP 101 may notify or instruct the STA 102 using an ACK 505 in response to a data frame 504 received on the NPCH. This allows such notifications and instructions to be executed even between communication devices that are not performing multi-link communication. FIG. 11C shows another example of a notification signal when notification is performed using a control frame. The control frame 1120 in FIG. 11C may be called an Extended ACK frame. Note that the control frame 1120 may be called by another name. The control frame 1120 includes a Frame Control field 1101, a Duration field 1102, an RA field 1103, and a Link ID field 1105. The same reference numerals are assigned to the same components as those in FIG. 11C , and descriptions thereof will be omitted. The subtype included in the Frame Control field 1101 of the Extended ACK frame may be Extended ACK. When the communication device 100 receives the control frame 1120, the Frame Control field 1101 indicates that the control frame 1120 is an Extended ACK frame, and the communication device 100 recognizes that the PCH has become available on one of the links. The communication device 100 also recognizes on which link the PCH has become available on the basis of the Link ID field 1105.

[0051] 9 illustrates an example in which the AP 101 receives a signal via NPCH access. However, if the AP 101 is transmitting a signal to the STA 102 via NPCH access, the AP 101 may autonomously terminate the NPCH access. For example, if the AP 101 determines that the PCH has become available while performing NPCH access, the AP 101 may transmit a CF-END without transmitting a data frame that was scheduled to be transmitted thereafter. By terminating the NPCH access depending on the status of the PCH, the communication device transmitting the NPCH access is more likely to be able to perform channel bonding using both the PCH and the NPCH at the next opportunity. This allows for efficient use of frequency resources.

[0052] As described above, in this processing example, the communication device 100 performing communication via NPCH access determines in parallel whether the PCH has become available, and if the PCH has become available, executes control to terminate the NPCH access. This increases the possibility that channel bonding using both the PCH and the NPCH will be possible at the next transmission opportunity, enabling efficient use of frequency resources.

[0053] As described above, according to the present embodiment, even when the PCH is unavailable, communication using the NPCH is performed based on carrier sensing in the SPCH. This enables efficient use of link frequencies, thereby increasing the communication capacity provided by the wireless communication system. Furthermore, according to the present embodiment, if the PCH becomes available during communication via NPCH access, control for communication using the PCH is performed. This enables signals transmitted on the PCH to be received normally. Furthermore, according to some embodiments, by controlling the timing at which the PCH and NPCH become available, the possibility of performing channel bonding using the PCH and NPCH at the next transmission opportunity is increased. This enables efficient use of frequency resources.

[0054] The present technology may 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 referred to as NPCH access has been exemplified, but the present invention is not limited thereto and may be referred to, for example, as secondary primary channel access. In the present embodiment, a case where a channel for determining whether or not to transmit using the NPCH is referred to as SPCH for convenience has been exemplified, but the present invention is not limited thereto. Among multiple secondary channels, a channel with a high priority for determining whether or not to transmit may be referred to as PSCH (Primary Secondary Channel). Whichever term is used, it means that the channel should be used to determine whether or not to transmit using the NPCH. Furthermore, the names of the information elements and various fields in the present embodiment may be referred to by other names. The operations of the communication device 100 in the above-described processing examples may be executed in combination with each other. For example, if the interference power caused on the NPCH due to the transmission of a signal on the PCH is smaller than a threshold, the communication device 100 that has determined that the PCH is available may transmit a reservation signal on the PCH. On the other hand, if the interference power caused on the NPCH due to the transmission of a signal on the PCH is greater than a threshold, the communication device 100 that has determined that the PCH is available may perform a receiving operation to receive a signal addressed to the device itself without transmitting a reservation signal on the PCH. Furthermore, when the communication device 100 has determined that the PCH is available, the communication device 100 may transmit a reservation signal on the PCH while instructing the other communication device to terminate NPCH access. In this case, in response to receiving a CF-END to cancel the NAV set on the NPCH due to the reservation signal, the communication device 100 may transmit a CF-END to cancel the NAV set on the PCH due to the reservation signal.

[0055] The present invention can also be realized by supplying a program that realizes one or more of the 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.The present invention can also be realized by a circuit (e.g., an ASIC) that realizes one or more of the functions.

[0056] 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.

[0057] This application claims priority based on Japanese Patent Application No. 2023-182053, filed on October 23, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A communication device that performs communication in accordance with the IEEE 802.11 standard series, comprising: communication means for performing communication with another communication device using a first channel access method that uses at least a primary channel in one link, and a second channel access method that does not use the primary channel when the primary channel is busy, and uses a non-primary channel different from the primary channel among multiple channels included in the link; and control means for performing, when the primary channel becomes available during a period in which communication is being performed with a first communication device using the second channel access method, a first control for transitioning an operation state of the communication device for the primary channel to a predetermined state, a second control for transitioning a state of the primary channel to a predetermined state, a third control for sending a predetermined signal to the first communication device that is performing communication using the non-primary channel, or a fourth control for terminating communication with the first communication device using the second channel access method. A communication device comprising:

2. The communications device according to claim 1, wherein the first channel access method is a primary channel access method in which access to a channel is made based on a result of carrier sense for the primary channel, and the second channel access method is a non-primary channel access method in which access to a channel is made based on a result of carrier sense for the non-primary channel.

3. The communication device according to claim 1, wherein the primary channel is a primary channel defined based on one standard in the IEEE 802.11 standard series, and the non-primary channel is a non-primary channel defined based on at least one standard in the IEEE 802.11 standard series.

4. The communication device according to claim 1, wherein the control means performs the first control, the second control, the third control, or the fourth control based on the end of a busy state of the primary channel during a period in which communication is being performed using the second channel access method.

5. The communication device according to claim 1, further comprising detection means for detecting that the primary channel has become available when a completion signal terminating a network allocation vector set in the primary channel is detected.

6. The communication device according to claim 5, wherein said detection means detects said completion signal transmitted using a CF (Contention Free)-END frame defined in the IEEE 802.11 series standards.

7. The communication device according to claim 1, wherein said control means, as said first control, transitions an operation state of said communication device for said primary channel from a power saving operation to a normal operation.

8. A communication device as claimed in any one of claims 1 to 6, wherein the control means performs, as the first control, control to transition the operation state of the communication device for the primary channel to a state in which a signal addressed to the communication device and transmitted on the primary channel by a second communication device different from the first communication device can be received while the communication device is receiving a signal from the first communication device using the second channel access method.

9. A communication device as claimed in any one of claims 1 to 6, wherein the control means performs, as the first control, control to transition the operation state of the communication device for the primary channel to a state in which a signal can be transmitted to a second communication device different from the first communication device via the primary channel while the communication device is transmitting a signal to the first communication device via the second channel access method.

10. The communication device according to any one of claims 1 to 6, wherein the control means performs control to transition the primary channel to a reserved state in which use of the primary channel is reserved, as the second control.

11. The communication device according to claim 10, wherein the control means controls the transmission of a reservation signal including a reservation period for the primary channel that is set based on a period during which the communication device is performing communication with the first communication device using the second channel access method.

12. The communication device according to claim 10, wherein said control means reserves the use of said primary channel by transmitting a CTS (Clear-to-Send)-to-Self frame defined in the IEEE 802.11 series standards.

13. The communication device according to claim 1, wherein the control means performs, as the third control, control to send to the first communication device a notification that the primary channel has become available or an instruction to end transmission using the second channel access method while the communication device is receiving a signal from the first communication device using the second channel access method.

14. The communication device according to claim 13, wherein said control means causes said communication means to transmit said notification or said instruction using a response to a signal from said first communication device.

15. The communication device according to claim 13, wherein the control means causes the communication means to transmit the notification or the instruction using a link different from the link.

16. A communication device according to any one of claims 1 to 15, wherein the control means, as the fourth control, controls the communication means so as to terminate the transmission period for communication by the second channel access method when the primary channel becomes available during a transmission period for communication by the second channel access method.

17. A communication method executed by a communication device that communicates with another communication device in accordance with the IEEE 802.11 standard series using a first channel access method that uses at least a primary channel in one link, and a second channel access method that does not use the primary channel when the primary channel is busy and uses a non-primary channel different from the primary channel among multiple channels included in the link, the method comprising: executing, when the primary channel becomes available during a period in which communication is being executed with a first communication device using the second channel access method, a first control for transitioning the operation state of the communication device for the primary channel to a predetermined state; a second control for transitioning the state of the primary channel to a predetermined state; a third control for sending a predetermined signal to the first communication device that is communicating using the non-primary channel; or a fourth control for terminating communication with the first communication device using the second channel access method.

18. A program for causing a computer included in a communication device that communicates with another communication device in accordance with the IEEE 802.11 standard series using a first channel access method that uses at least a primary channel in one link, and a second channel access method that does not use the primary channel when the primary channel is busy and uses a non-primary channel different from the primary channel among multiple channels included in the link, to execute a first control for transitioning the operation state of the communication device for the primary channel to a predetermined state when the primary channel becomes available during a period in which communication is being performed with the first communication device using the second channel access method, a second control for transitioning the state of the primary channel to a predetermined state, a third control for sending a predetermined signal to the first communication device that is communicating using the non-primary channel, or a fourth control for terminating communication with the first communication device using the second channel access method.

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