Communication apparatus, method for controlling communication apparatus, and storage medium

Abstract

To provide a technique for controlling whether to use a function of performing communication using another channel when a primary channel is busy, on the basis of the type of a channel provided by a network.SOLUTION: A communication device that supports a function of attempting to acquire a transmission opportunity in a non-primary channel different from a primary channel in a case where another communication device acquires the transmission opportunity in the primary channel performs control such that acquisition of the transmission opportunity in the non-primary channel by the function is not attempted even in a case where another communication device acquires the transmission opportunity in the primary channel of the network in the 2. 4GHz band in a case where communication is performed in the network in the 2. 4GHz band.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a communication device that performs wireless communication, a control method for the communication device, and a program. [Background technology]

[0002] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is known as a communication standard for wireless local area networks (WLANs). The IEEE 802.11be standard and its successor, the IEEE 802.11bn standard, aim to reduce communication latency and improve channel utilization efficiency.

[0003] As a candidate technology, a technology for improving channel utilization efficiency in the case where communication is performed using a communication link consisting of multiple channels is being considered. For example, Patent Document 1 describes a technology for performing communication using other channels when the primary channel used to acquire the transmission right is unavailable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2020 / 413465 Summary of the Invention [Problem to be solved by the invention]

[0005] However, depending on the frequency band, the above-described function may not significantly contribute to improving utilization efficiency. For example, in a frequency band with few channel options, all channels are often equally congested. In view of this, one object of the present invention is to provide a technology for controlling whether to use a function for communicating using other channels when the primary channel is busy, based on the type of frequency band in which the network is provided. Another object of the present invention is to change an initial setting value for whether to use a function for communicating using other channels when the primary channel is busy, based on the type of frequency band. Another object of the present invention is to improve convenience in a communication system using a communication link. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present invention is a communication device that supports a function of attempting to acquire a transmission opportunity on a non-primary channel different from the primary channel on which data is to be transmitted, when another communication device acquires a transmission opportunity on the primary channel on which data is to be transmitted, and is characterized in that, when communicating on a 2.4 GHz band network, the communication device has communication control means that controls the function not to attempt to acquire a transmission opportunity on the non-primary channel, even if another communication device acquires a transmission opportunity on the primary channel of the 2.4 GHz band network. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to control whether or not to use a function for communicating using other channels when the primary channel is busy, based on the type of channel provided by the network. According to another aspect of the present invention, it is possible to improve the convenience of a communication system using a communication link. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 illustrates an example of a configuration of a network system. [Figure 2] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Figure 3] FIG. 2 illustrates an example of a software configuration of a communication device. [Figure 4] FIG. 10 is a schematic diagram illustrating an example of a channel access procedure. [Figure 5] FIG. 2 is a schematic diagram illustrating an example of a functional module for channel access. [Figure 6] FIG. 1 is a schematic diagram illustrating channels in the 2.4 GHz band. [Figure 7] 10 is a flowchart illustrating an example of control of an AP. [Figure 8] 10 is a flowchart illustrating an example of control in the STA. [Figure 9] 10 is a flowchart illustrating channel access control in an AP / STA. [Figure 10] FIG. 1 is a schematic diagram illustrating channels in the 5 GHz band. [Figure 11] 10 is a flowchart illustrating an example of control of an AP in the second embodiment. [Figure 12] 10 is a flowchart illustrating an example of control of an STA in the second embodiment. [Figure 13] FIG. 11 is a schematic diagram illustrating an example of initial setting information stored in an AP in the third embodiment. [Figure 14] FIG. 13 is a diagram illustrating an example of a setting screen provided by an AP in the third embodiment. [Figure 15] FIG. 13 is a diagram showing an example of a reset screen provided by an AP in the third embodiment. [Figure 16] 10 is a flowchart illustrating an example of control of an AP according to the third embodiment. [Figure 17] FIG. 10 is a diagram for explaining a modified example of the reset operation. 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] First Embodiment An example of the configuration of a network system according to this embodiment is shown in Fig. 1. The network system according to this embodiment includes one access point device (hereinafter simply referred to as an AP, AP STA, or access point) and two station devices (hereinafter simply referred to as STAs, Non-AP STAs, or stations).

[0011] The AP 101 and the STAs 102 and 103 are configured to be able to communicate wireless frames that comply with the IEEE802.11bn standard, which is the successor to the IEEE802.11be standard and targets a maximum transmission speed of 46.08 Gbps.

[0012] IEEE stands for Institute of Electrical and Electronics Engineers. IEEE802.11bn, the successor standard to IEEE802.11be, boasts high reliability, low latency, and improved throughput during periods of congestion as its main features. Wireless frames used in this successor standard are also called UHR (Ultra High Reliability) PPDUs. PPDU stands for Physical Layer Protocol Data Unit.

[0013] The name UHR was chosen for convenience, taking into account the goals and key features of the successor standard, and may be renamed once the standard is fully developed. Similarly, the name IEEE 802.11bn may be renamed once the standard is fully developed. However, it should be noted that this specification and the accompanying claims are essentially applicable to all successor standards to the 802.11be standard.

[0014] 1, the AP 101 is an access point that supports a multi-band function that provides networks using multiple different frequency channels. In this embodiment, the AP 101 is a tri-band access point that provides a 2.4 GHz band network, a 5 GHz band network, and a 6 GHz band network, as an example.

[0015] Furthermore, the AP 101 and STA 102 of this embodiment can establish multiple communication links between devices and perform multi-link communication. Hereinafter, a communication link is also simply referred to as a link. The AP 101 that performs multi-link communication is also referred to as an AP multi-link device (AP MLD) 101, and the STA 102 that performs multi-link communication is also referred to as a non-AP MLD 102.

[0016] For example, AP 101 can establish a link in the 2.4 GHz band network with STA 102 and communicate with them. In parallel with this, AP 101 and STA 102 can also establish a link in the 5 GHz band and communicate with them. In this case, STA 102 performs multi-link communication, which communicates via multiple links.

[0017] 1 shows a network system consisting of one AP 101, STAs 102, and 103 as an example, but the number of STAs constituting the network system may be greater than that shown. Furthermore, while the AP 101 and STAs 102-103 are described as supporting UHR PPDU communication (transmission and reception), they can also be configured to support PPDU communication of legacy standards that predate the UHR standard. Specifically, the AP 101 and STA 102 can be configured to support PPDU transmission and reception of IEEE 802.11a / b / g / n / ac / ax / be standards, etc.

[0018] Furthermore, the frequency bands used by the AP 101 and the STAs 102-3 are not limited to the 2.4 GHz, 5 GHz, and 6 GHz bands described above. For example, different frequency bands such as the Sub-1 GHz band and the millimeter wave band may be used. Furthermore, the AP 101 and the STAs 102 can communicate using bandwidths such as 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, and 640 MHz. The bandwidths used by each communication device are not limited to these.

[0019] The IEEE802.11 series of standards specifies a frequency channel with a bandwidth of 20 MHz as the minimum channel in frequency bands such as 2.4 GHz, 5 GHz, and 6 GHz. The standards also define multiple available channels in each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. The standards also allow a channel to be used in combination with adjacent channels.

[0020] In this embodiment, the use of a channel in combination with another adjacent channel is sometimes called channel bonding. Also, a bundle of channels formed by one or two or more adjacent channels is sometimes called a link. For example, one link formed by two channels with a bandwidth of 20 MHz uses a bandwidth of 40 MHz.

[0021] The AP 101 establishes one or more links between devices to communicate data with the STAs 102 and 103. For example, the STA 102 performs a connection procedure with the AP 101 to establish a link with the AP 101. When the connection procedure between the STA 102 and the AP 101 is completed, a link is established between the devices. Establishing a link enables a communication device such as an AP or a STA to access a wireless medium and communicate data, etc., with the other communication device. For example, if a link using a 160 MHz bandwidth is established between devices, the AP 101 and the STA 102 communicate using all or some of the channels that make up the link. A link using a 160 MHz bandwidth can be configured by bundling eight channels with a bandwidth of 20 MHz.

[0022] Before transmitting data, STAs such as the AP 101 and the STA 102 perform carrier sensing to determine whether transmission is possible. For example, a communication device measures the strength of a signal received on a channel that the device intends to use for transmission (received signal strength), and if the received signal strength exceeds a predetermined threshold, determines that a signal is present on that channel. Furthermore, the communication device determines a transmission period for transmitting a signal based on information such as a Duration field included in the signal received on the channel. For example, the communication device stores the period indicated by the Duration field included in the received signal as a Network Allocation Vector (NAV) within the device. The communication device may treat the stored NAV as a period during which the device will not transmit. The operation of the communication device to set a period during which the device will not transmit based on information such as the Duration field of the received signal is also referred to as setting a NAV. If the communication device determines that a signal is present on the channel through carrier sensing, or if the set NAV period has not expired, the communication device may determine that transmission is not possible. In this case, the channel state may be referred to as a busy state. On the other hand, a state in which no signal is detected on a channel during carrier sensing and no NAV is set may be referred to as an idle state. A communication device may determine that transmission is possible when the channel is idle. Note that, for example, when communicating using a 160 MHz bandwidth link, a communication device may perform a first-stage determination of whether transmission is possible using only the Primary Channel (PCH). The PCH is a channel over which an AP broadcasts a Beacon frame that broadcasts network information. The PCH is one of eight 20 MHz bandwidth channels that make up the 160 MHz bandwidth link, and may be notified to STA 102, for example, by a Beacon frame periodically broadcast by AP 101. For example, if AP 101 or STAs 102 to 103 determine that transmission is possible as a result of performing carrier sensing on the PCH for a predetermined period, they may perform a second-stage determination to confirm whether an adjacent channel to be used for channel bonding is idle.Then, a communication device may perform channel bonding transmission using the channel determined to be available for transmission in the first stage and another channel determined to be idle in the second stage and included in the same link. For example, a 160 MHz-wide PPDU may be transmitted. Furthermore, if a communication device 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 constituting a link may be called a secondary channel (SCH). A secondary channel may also be called a non-primary channel (NPCH). As described above, the previous IEEE 802.11 series standards provided the PCH as a channel used to pre-determine whether transmission is possible and as a channel for transmitting beacons. Furthermore, a channel access mechanism is employed in which, if the PCH is busy, transmission is not attempted even if the channel to be bonded is idle. While this operation is useful in terms of resolving interference issues, the fact that other idle channels (SCHs) are not used when the PCH is busy leads to reduced frequency utilization efficiency. For example, consider a case where another communication device (e.g., a STA or AP belonging to a different wireless network) transmits a frame using a 20 MHz-wide channel corresponding to the PCH of AP 101, STAs 102, and 103. In this case, even if the other seven SCHs are idle, AP 101 and STAs 102 to 103 determine that the channel is busy and are therefore unable to transmit using those SCHs. In this situation, even if STA 102 transmits to AP 101 using a specific idle SCH channel, AP 101 can properly receive the signal transmitted by STA 102. In this way, if a configuration is adopted in which the remaining 140 MHz of idle SCHs are not utilized because, for example, a 20 MHz PCH is being used by another network, this would impair the efficient use of frequency resources.In this embodiment, when a PCH is being used by another communication device, a function is provided to perform communication between communication devices using an SCH (or NPCH) included in the same link as the PCH without using the PCH. As an example, when the AP 101 or the STAs 102 and 103 determine that the PCH is busy, they transition to a Secondary Primary Channel (SPCH) for determining whether transmission using the SCH (or NPCH) is possible.

[0023] If the AP 101 or the STAs 102 and 103 determine that the PCH is being used by another communication device, they subsequently determine whether transmission is possible on the SPCH. If they determine that transmission is possible, they transmit using one or more SCHs including the SPCH. This channel access for transmitting using one or more channels including the SPCH without using the PCH can be called NPCA (Non-Primary Channel Access). A series of communication functions for transitioning to the SPCH and attempting channel access is also called an NPCA function or NPCA operation. In NPCH access, the transmitting communication device attempts channel access on the SPCH channel and transmits a signal to the other communication device using one or more SCHs including the SPCH channel. Meanwhile, the receiving communication device waits for a signal transmitted from the other communication device using one or more SCHs including the SPCH channel and performs a reception process to receive the signal as needed. To perform NPCH access, the AP 101 and the STAs 102 to 103 share information about NPCH access (such as information identifying the SPCH) with the other communication device in advance. Information identifying the SPCH can be included in, for example, a Secondary Primary Channel Announcement Element of a Beacon frame. This Element can be configured with information indicating the Operating Class of the SPCH and information indicating the Channel. The Operating Class is an identifier that can uniquely identify a frequency band determined by the country or region in which the AP 101 is used. The Channel is an identifier that can uniquely identify each channel included in the frequency band identified by the Operating Class. The AP 101 may indicate the position of the SPCH by storing in this Element the relative position of the SPCH on the frequency axis with respect to the PCH. For example, assume that the communication device 100 uses a link with a bandwidth of 160 MHz in the 6 GHz band and sets one channel in that band as the PCH (20 MHz bandwidth). Also assume that the SCHs (20 MHz bandwidth) are 5ch, 9ch, 13ch, 17ch, 21ch, 25ch, and 29ch, respectively.When the communication device 100 sets 21ch as the SPCH, it sets 20 as information for identifying the SPCH. That is, 20, which is the relative distance on the frequency axis from 1ch, which is the PCH, to 21ch, which is the SPCH, can be set as information for identifying the SPCH. Furthermore, this embodiment provides a mechanism for controlling whether to use a function for communicating using other channels when the primary channel is busy, based on the type of channel provided by the network. Note that the names of the elements are merely examples and are not limited to these.

[0024] An example of the channel access operation in this embodiment will be specifically described below. The AP 101 and the STAs 102 and 103 can also be configured to support wireless communication based on other communication standards, such as Bluetooth (registered trademark), NFC, and Bluetooth (registered trademark) LE (Low Energy). NFC stands for Near Field Communication. The AP 101 and the STAs 102 and 103 can also be configured to support wired communication using an Ethernet cable or wired communication using optical fiber. Specific examples of the AP 101 include, but are not limited to, a wireless LAN router, a personal computer (PC), a smartphone, a tablet terminal, and a signage device. The AP 101 and the STAs 102 and 103 may also be information processing devices, such as wireless chips that support the transmission and reception of UHR PPDUs. In this case, various controls can be performed by hardware circuits within the wireless chip. Various processes can also be performed by collaboration between a processor, memory, and hardware circuits, such as an ASIP, within the wireless chip. ASIP stands for Application-Specific Instruction Set Processor.

[0025] Specific examples of the STA 102 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, printers, projectors, and wearable devices such as smart glasses.

[0026] <Hardware configuration of communication device> 2 shows an example of the hardware configuration of a communication device (AP 101, STAs 102 to 103). The communication device includes, as an example of the hardware configuration, a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207.

[0027] The storage unit 201 is configured with a ROM and / or a RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. RAM stands for Random Access Memory, and ROM stands for Read Only Memory. Note that, in addition to memories such as ROM and RAM, the storage unit 201 may also use storage media such as non-volatile storage devices such as hard disks and solid state drives (SSDs).

[0028] The control unit 202 is configured with, for example, a processor such as a CPU or MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc. Here, CPU stands for Central Processing Unit, and MPU stands for Micro Processing Unit. The control unit 202 executes programs stored in the storage unit 201 and controls the entire device by operating hardware circuits such as the ASIC. Note that the control unit 202 may control the entire device in cooperation with the programs stored in the storage unit 201 and an OS (Operating System).

[0029] The control unit 202 also controls the functional unit 203 to perform predetermined processing, such as capturing images, printing, and projection. The functional unit 203 is hardware that enables the device to perform predetermined processing. For example, if the communication device is a camera such as a digital still camera or a smartphone equipped with a camera, the functional unit 203 is an imaging unit that captures images of the surroundings via a camera unit (not shown) included in the communication device. For example, if the communication device is a printer, the functional unit 203 is a printing unit that prints on a sheet such as paper based on print data obtained from an external device via wireless communication. For example, if the communication device is a projector or smart glasses, the functional unit 203 is a projection unit that projects image data or video data obtained from an external device via wireless communication. In the case of smart glasses, the projection surface is the end user's retina, for example. The data processed by the functional unit 203 may be data stored in the storage unit 201 or data communicated with another AP or STA via the communication unit 206 (described later). Furthermore, communication devices such as the AP 101 can also provide network storage functions such as a network-attached storage (NAS). This function is provided to other communication devices as a web service such as a network storage service. For example, a communication device such as an STA connects to a network storage service provided by an AP 101 or the like using a protocol such as SMB, FTP, or WebDAV. The communication device such as an STA then uploads files to the storage service or downloads files from the storage. This upload and download data communication is also realized by communicating UHR PPDUs between devices.

[0030] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes, for example, at least one of display on a screen, audio output by a speaker, and vibration output. Note that both the input unit 204 and the output unit 205 may be implemented by a single module, such as a touch panel. The output unit 205 functions as a display means for presenting information to the user. The input unit also functions as a reception means for receiving user operations.

[0031] The communication unit 206 controls wireless communications compliant with the IEEE802.11 series of standards and IP communications. In this embodiment, the communication unit 206 cooperates with the antenna 207 to execute communication control for transmitting and receiving UHR PPDUs, which are wireless frames of the UHR standard, and PPDUs conforming to earlier standards. The antenna 207 is an antenna capable of transmitting and receiving signals in at least one frequency band, for example, the sub-GHz band, the 2.4 GHz band, the 5 GHz band, the 6 GHz band, and the millimeter wave band. Note that, although a communication device equipped with two antennas is illustrated as an example in this embodiment, the present invention is not limited to this. The number of antennas may be three or more.

[0032] If the communication device is compatible with the NFC standard, Bluetooth standard, wired communication standard, or the like, the communication unit 206 may be configured to control wireless communication or wired communication in accordance with these communication standards.

[0033] Next, the functional configuration of the AP 101 and the STAs 102 to 103 will be described with reference to Fig. 3. The communication devices such as the AP 101 and the STAs 102 to 103 have functional units such as a frame processing unit 301, a mode control unit 302, a frame transmission / reception unit 303, a setting management unit 304, and a UI control unit 305.

[0034] The mode control unit 302 cooperates with each functional unit and each hardware unit to control the operation mode, such as whether to use the NPCA function, and to control the connection with the opposing device. Specifically, the connection process involves authentication processing, association processing, 4-way handshake processing, and the like, to establish a communication link with the opposing communication device. In the case of AP101, the opposing device is a STA such as STA102, and in the case of STA102, the opposing device is an AP such as AP101. The control unit 302 also manages communication parameters to be used in each operation mode. The communication parameters managed by the control unit 302 are communication parameters determined based on values ​​in the operation setting DB 304b (described later) and communication parameters determined during the connection process with the opposing device.

[0035] When switching the operation mode, the control unit 302 requests the frame transmitting / receiving unit 303 to switch the communication conditions. Upon receiving the request to switch, the transmitting / receiving unit 303 controls the communication unit 206 and the multiple antennas 207 to switch the communication conditions required for transmission and reception. The control unit 302 of the AP 101 also manages information about STAs currently connected to the network provided by the AP 101.

[0036] The frame processing unit 301 generates and analyzes signals (frames) when communicating with a communication device that is the communication partner. The frame processing unit 301 generates management frames for the communication device to execute connection procedures and control frames for controlling communication. The frames generated and analyzed by the processing unit include Beacon, Probe Request, Probe Response, Association Request, Association Response, F1S (Fast Initial Link Setup), Discovery, and Action. Authentication frames are also included. ReAssociation Request and ReAssociation Response are also included. The frame processing unit 301 also generates data frames and QoS (Quality of Service) data frames based on instructions from an upper-level application (not shown). The processing unit 301 also generates and analyzes other IEEE 802.11 standard series frames as appropriate, but a description of these is omitted due to space limitations.

[0037] The frame transmitting / receiving unit 303 performs transmission processing of wireless frames generated by the frame processing unit 301 and reception processing of wireless frames from the other device. The transmission processing will be described later with reference to FIG. 5. The received digital data obtained by the reception processing is transferred to the processing unit 301. The processing unit 301 analyzes the received digital data transferred from the transmitting / receiving unit 303, and depending on the analysis results, performs processing to generate an appropriate response frame or notify an upper layer (not shown) of the analyzed data (such as IP data included in the payload). This frame transmitting / receiving unit 303 cooperates with each unit to perform transmission control for transmitting frames and reception control for receiving frames.

[0038] The UI (User Interface) control unit 305 provides a setting screen as a UI for the user to input communication-related settings. Furthermore, the UI control unit 305 requests the setting management unit 304 to change the operational settings of the communication device in response to a user operation on the setting screen via the input unit 204. Upon receiving the request to change the operational settings, the management unit 304 overwrites the setting values ​​stored in the operational setting DB 304b based on the changed setting values ​​indicated in the change request. The setting DB 304b stores user setting values ​​that can be changed via the setting screen provided by the UI control unit. These user setting values ​​include a user setting value indicating the SSID of the network, a user setting value indicating the network operating channel, a user setting value indicating the authentication method to be used, settings related to IP communication, and the like. SSID stands for Service Set Identifier and is a human-readable identifier used to identify the destination network. In the present embodiment, the setting screen is displayed and provided to the user via the output unit 205 of the AP 101 or the STAs 102-103. However, the method of providing the setting screen is not limited to this. For example, the UI control unit 305 of the AP 101 can function as an HTTP server and provide web content corresponding to the setting screen to the STAs providing the network connection, thereby providing the setting screen to the user. The connection with the STAs may be via an Ethernet cable or wirelessly. HTTP stands for Hypertext Transfer Protocol. For example, the AP 101 provides web content corresponding to each setting screen described in the above embodiment in response to a request (HTTP request) from a web browser application included in the connected STA. The web browser application of the STA, such as the STA 102, that receives the web content displays the setting screen as a web screen based on the received web content. Furthermore, the web browser application of the STA transmits information identifying the operation performed via the display items on the web screen to the HTTP server. The transmission can be performed using a POST method or the like.The UI control unit 305 identifies the user setting items to be changed and the user setting values ​​after the change based on information identifying the operation content received from the STA's web browser application using a POST method or the like. The control unit 305 then requests the management unit 304 to change the operation settings so that the values ​​of the identified setting items are changed to the identified user setting values. The management unit 405, upon receiving the change request, overwrites the setting values ​​in the operation setting DB 304b based on the change request. The setting management unit also has an initial setting DB 304a used when resetting to factory settings, which will be described later. The initial setting DB 304a stores initial setting information for resetting to factory settings. When an instruction to reset to factory settings is detected, the setting management unit 304 resets the operation settings of the communication device to the factory settings by overwriting the settings in DB 304b with the setting values ​​in DB 304a.

[0039] <Channel Access> Next, an example of a channel access procedure in this embodiment will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing an example of a channel access procedure in this embodiment.

[0040] At a timing before reference numeral 400, STA102 and STA103 attempt channel access on the PCH to transmit data. At this time, while the PCH is idle, STA102 and STA103 decrease the transmission wait time, including the IFS and backoff counter determined based on the backoff algorithm. When the PCH idle transmission wait time reaches zero, STA102 or STA103 can start data transmission. However, if a communication device in the OBSS wins channel access to the idle PCH first, the PCH becomes busy. This situation means that another communication device wins the transmission opportunity on the PCH where STA102 or STA103 plans to transmit data. Figure 3 illustrates an example in which a communication device in the OBSS starts data transmission on the PCH first. The dashed line in reference numeral 400 indicates the timing when the communication device in the OBSS starts data transmission on the PCH first. IFS stands for Inter Frame Space, and OBSS stands for Overlapping Basic Service Sets.

[0041] At the timing indicated by the reference numeral 400, the AP 101 and the STAs 102 to 103 switch the channel to be monitored for channel access to the SPCH described above and attempt to acquire a transmission opportunity on the secondary channel. At this time, terminals in the BSS provided by the AP 101, such as the AP 101 and the STAs 102 to 103 of this embodiment, perform backoff in the SPCH. In this embodiment, in order to realize data communication on the SPCH with a simple implementation, a restriction is imposed so that data communication on the SPCH is permitted only during periods when the PCH is busy. BSS stands for Basic Service Set and refers to the IEEE 802.11 wireless network provided by the AP to the STAs.

[0042] Reference numerals 401 and 402 indicate the transmission waiting time of each STA in the SPCH. Here, a situation is illustrated in which the transmission waiting time of STA 102 is shorter than the transmission waiting time of STA 103. Fig. 3 illustrates a case in which STA 102, which has a shorter transmission waiting time, wins a transmission opportunity in the SPCH and transmits data.

[0043] STA 102, which has won the transmission opportunity, transmits a frame to AP 101 on one or more SCHs, including the SPCH. Meanwhile, STA 103 decreases the transmission wait time, including the backoff counter, while the SPCH is idle. The dashed-dotted line shown in 403 indicates the timing at which the PCH transmission opportunity expires for the communication device of the OBSS. At this timing, AP 101 and STAs 102 to 103 switch the channel monitored for channel access to the PCH. That is, AP 101 and STAs 102 to 103 re-transition to the normal state where they perform channel access on the PCH. The communication device that has re-transitioned to the normal state attempts channel access on the idle PCH. Reference numeral 404 indicates the case where a STA that has returned to the PCH wins the transmission opportunity. STA 103, which has won the transmission opportunity by channel access on the PCH, transmits a frame to AP 101 on one or more channels, including the PCH. The back-off parameters after transition to SPCH may be calculated using a different calculation method from that used for PCH, or may be calculated again using the same calculation method. After re-transition to PCH, the back-off parameters before the transition may be stored and reused, or the back-off parameters before the transition may be discarded and new back-off parameters may be recalculated to perform back-off.

[0044] Next, the functional configuration of the AP 101 and the STAs 102 to 103 will be described with reference to Fig. 5. Fig. 5 is a schematic diagram illustrating an example of functional modules for channel access provided in the AP 101 and the STAs 102 to 103. Fig. 5 shows functional modules that perform the transmission function of the frame transceiver 303. Fig. 5 also shows excerpts of functional modules that realize functions related to channel access. A data categorizer 501 classifies data received from an upper layer into traffic categories that comply with the EDCA mechanism defined in the IEEE802.11e standard. EDCA stands for Enhanced Distributed Channel Access.

[0045] In the EDCA mechanism, data transmission is prioritized by classes so that certain types of traffic are given priority. Specifically, the categorizer 501 classifies data into one of four access categories (ACs) defined in the EDCA mechanism. Typically, the four ACs are "AC_VO" for voice, "AC_VI" for video, "AC_BE" for best effort, and "AC_BK" for background data.

[0046] Next, the categorization unit 501 stores the categorized data (MAC frames) in a queue 502 corresponding to the categorized AC. The queue 502 is also called a traffic buffer. MAC is an abbreviation for Medium Access Control.

[0047] Channel access control section 505 includes CSMA / CA execution section 503 and backoff and collision control section 504. CSMA / CA execution section 503 performs channel access control based on CSMA / CA for data held in the corresponding queue.

[0048] When the CSMA / CA execution unit 503 detects that data has been stored in the corresponding queue, it reads the EDCA parameters associated with the corresponding queue stored in the control unit 504. Based on the read EDCA parameters, the execution unit 503 then determines a transmission wait time consisting of an AIFS and a backoff counter. Hereinafter, the transmission wait time including the AIFS and the backoff counter is simply referred to as the backoff parameter. The EDCA parameters are assigned in the order of VO, VI, VE, and BK so that wireless signal transmission is given relative priority. The EDCA parameters include CWmin, CWmax, AIFS, and TXOPLimit. CWmin is the minimum value of the CW (Contention Window), which is the transmission wait time, and CWmax is the maximum value of the CW. The shorter the CWmin and CWmax, the easier it is to obtain a transmission opportunity. AIFS (Arbitration Inter Frame Space) is the transmission interval between wireless signals. The smaller the AIFS, the easier it is to obtain a transmission opportunity. TXOPLimit is the upper limit of TXOP, which is the channel occupation time. The larger the TXOPLimit, the more data is allowed to be transmitted in one acquired transmission opportunity.

[0049] Next, the execution unit 503 decrements the set backoff parameter while a condition, such as the channel state notified by the control unit 504 being an idle state, is satisfied, and waits for transmission until the waiting time reaches zero. The execution unit 503 stops decrementing the backoff parameter while a condition, such as the channel state notified by the control unit 504 being a busy state, is satisfied. Then, when the execution unit 503 determines that the waiting time has reached zero, it determines that a transmission opportunity has been won. Having determined that a transmission opportunity has been won, the execution unit 503 retrieves data (MAC frames) from the queue and, in cooperation with the control unit 504, the communication unit 206, and the antenna 207, transmits a UHR PPDU including the retrieved MAC frame to another communication device. When a communication device attempts to acquire a transmission opportunity on the PCH and acquires the transmission opportunity, it transmits the UHR PPDU on one or more channels including the PCH. Furthermore, when a communication device attempts to acquire a transmission opportunity on the SPCH and acquires the transmission opportunity, it transmits the UHR PPDU on one or more channels including the SPCH.

[0050] The control unit 504 also performs arbitration when there is an internal collision between the execution units 503 when acquiring a transmission opportunity. When execution units 403 corresponding to different ACs simultaneously win a transmission opportunity and request transmission, the control unit 504 performs control to prioritize data stored in a queue with a higher priority. For example, when an execution unit corresponding to a VO queue and an execution unit corresponding to a BK queue simultaneously acquire a transmission opportunity, the control unit 504 transmits the data stored in the VO queue with priority. At this time, the control unit 504 notifies the execution unit corresponding to the BK queue that a collision has occurred, and increases the CW managed by the execution unit corresponding to the BK queue.

[0051] The control unit 504 controls notifying the execution unit 503 of changes in channel conditions, and controls transition notifications indicating that the channel for which channel access is attempted has transitioned to SPCH and re-transition notifications indicating that the channel has re-transitioned to PCH. Upon receiving the transition notification or re-transition notification, the execution unit 503 updates the back-off parameters as necessary.

[0052] <Communication Control> Next, communication control related to the NPCA of this embodiment will be described using the schematic diagram of FIG. 6 and the flowcharts of FIGS. 7 to 9. The schematic diagram of FIG. 6 is a diagram illustrating channel allocation in the 2.4 GHz band. Each process shown in the flowchart of FIG. 7 is executed by the processor of the control unit 202 of the AP 101 executing a computer program stored in the storage unit 201. Note that some processes, such as transmission and modulation, are realized in cooperation with the processor of the control unit 202, various processors, ASICs, DSPs, FPGAs, etc., constituting the communication unit 206, and the ASICs, DSPs, FPGAs, etc., constituting the antenna and control unit 202. Note that, when it is necessary to clearly indicate the subject of a process, the functional units described in FIGS. 3 and 5 will be used as the subject. FIG. 7 illustrates startup control that is executed when a commercial power source is connected to the AP 101 and a power button (not shown) is pressed. Each process shown in the flowchart of FIG. 7 is executed by the processor of the control unit 202 of the AP 101 executing a computer program stored in the storage unit 201. Note that some of the processing, such as transmission and modulation, is realized in cooperation with the processor of the control unit 202, various processors, ASICs, DSPs, FPGAs, etc., constituting the communication unit 206, and the ASICs, DSPs, FPGAs, etc., constituting the antenna and control unit 202. Note that, when it is necessary to clearly indicate the subject of processing, the functional units described in FIGS. 3 and 5 will be used as the subject. FIG. 8 shows connection control when STAs such as STAs 102-103 connect to APs such as AP 101. The flowchart of FIG. 9 shows channel access control of NPCA executed by the AP 101 and the STAs 102-103. Each process in FIG. 9 is also executed by the processor of the control unit 202 of the AP 101 and the STAs 102-103 executing a computer program stored in the storage unit 201. Some of the processing, such as transmission and modulation, in FIG. 9 is realized in cooperation with the processor of the control unit 202, various processors, ASICs, DSPs, FPGAs, etc., constituting the communication unit 206, and the ASICs, DSPs, FPGAs, etc., constituting the antenna and control unit 202.

[0053] First, let us explain the 2.4 GHz channel configuration using Figure 6. Typically, the 2.4 GHz band has channels 1 through 13. Each channel is approximately 20 MHz wide, but adjacent channels are configured such that frequency overlap occurs. Therefore, to avoid interference, it is common practice to space the channel on which one AP provides its BSS apart from the channel on which another AP provides its BSS by five channels. In Japan, APs often select channels 1, 6, and 11, indicated by the dashed lines, as the channels on which they provide their BSS. As shown in Figure 6, there are approximately three channels in the 2.4 GHz band that can be used to avoid interference. Therefore, in the 2.4 GHz band, many APs typically select one of these three channels to operate. Given this channel configuration, even if a transition to a SPCH, another channel in the 2.4 GHz band, is made, there is a high probability that an OBSS AP will also be present on the transitioned channel, and it is expected that channel utilization efficiency will not be significantly improved. In view of this, in this embodiment, the AP 101 is configured to disable the NPCA function when providing a 2.4 GHz BSS to the surrounding area.

[0054] Next, specific control will be explained using the flowcharts of Figures 7 to 9. In S701, the mode control unit 302 of the AP 101 acquires an operational setting from the operational setting DB 304b managed by the setting management unit 304. Subsequently, in S702, the control unit 302 determines, based on the acquired operational setting, whether or not the operational setting to provide a BSS in the 2.4 GHz band has been configured. If the control unit 302 determines that the operational setting to provide a BSS in the 2.4 GHz band has been configured, the process proceeds to S703. On the other hand, if the control unit 302 does not determine that the operational setting to provide a BSS in the 2.4 GHz band has been configured (i.e., if the control unit 302 determines that the operational setting not to provide a BSS in the 2.4 GHz band has been configured), the process proceeds to S704.

[0055] In S703, the control unit 302 starts providing a 2.4 GHz BSS with the NPCA function disabled. The AP 101 starts transmitting Beacon frames on the primary channel of the 2.4 GHz BSS to notify surrounding STAs of its presence. The control unit 302 cooperates with each unit to generate a Beacon frame including an information element in which a subfield indicating NPCA capability is set to "0," indicating that NPCA is not supported or is disabled, and transmits the frame on the primary channel of the 2.4 GHz band.

[0056] In S704, the control unit 302 determines whether the operation setting for providing a BSS in the 5 GHz band is set based on the acquired operation setting. If the control unit 302 determines that the operation setting for providing a BSS in the 5 GHz band is set, the process proceeds to S705. On the other hand, if the control unit 302 does not determine that the operation setting for providing a BSS in the 5 GHz band is set (i.e., if the control unit 302 determines that the operation setting for not providing a BSS in the 5 GHz band is set), the process proceeds to S708.

[0057] In S705, the control unit 302 determines, based on the acquired operation settings, whether or not a user setting has been made to disable the NPCA function in the 5 GHz band BSS. If the control unit 302 determines that a user setting has been made to disable the NPCA function in the 5 GHz band BSS, the process proceeds to S706. If the control unit 302 determines that a user setting has not been made to disable the NPCA function in the 5 GHz band BSS (i.e., if the control unit 302 determines that a user setting has been made to enable the NPCA function in the 5 GHz band BSS), the process proceeds to S707.

[0058] In S706, the control unit 302 starts providing a 5 GHz BSS with the NPCA function disabled. It starts transmitting Beacon frames on the primary channel of the 5 GHz BSS to notify surrounding STAs of its presence. The control unit 302 cooperates with each unit to generate a Beacon frame including an information element in which a subfield indicating NPCA capability is set to "0," indicating that NPCA is not supported or is disabled, and transmits the frame on the primary channel of the 5 GHz band. This information element can be included in the UHR PHY Capabilities Element.

[0059] In S707, the control unit 302 starts providing a 5 GHz BSS with the NPCA function enabled. It starts transmitting Beacon frames on the primary channel of the 5 GHz BSS to notify surrounding STAs of its presence. The control unit 302 cooperates with each unit to generate a Beacon frame including an information element in which a subfield indicating NPCA capability is set to "1," indicating that NPCA is supported, and transmits the frame on the 5 GHz primary channel. This information element can be included in the UHR PHY Capabilities Element. The Beacon frame can also include information for identifying the SPCH to which the transition will be made, as described above.

[0060] In S708, the control unit 302 determines whether the operation setting for providing a 6 GHz BSS is configured based on the acquired operation setting. If the control unit 302 determines that the operation setting for providing a 6 GHz BSS is configured, the process proceeds to S709. On the other hand, if the control unit 302 does not determine that the operation setting for providing a 6 GHz BSS is configured (i.e., if the control unit 302 determines that the operation setting for not providing a 6 GHz BSS is configured), the control unit 302 ends the series of startup processes.

[0061] In S709, the control unit 302 determines whether the NPCA function is disabled in the 6 GHz band BSS based on the acquired operation settings. If the control unit 302 determines that the NPCA function is disabled in the 6 GHz band BSS, the process proceeds to S710. If the control unit 302 determines that the NPCA function is not disabled in the 6 GHz band BSS (i.e., if the control unit 302 determines that the NPCA function is disabled in the 6 GHz band BSS), the process proceeds to S711.

[0062] In S710, the control unit 302 starts providing a 6 GHz BSS with the NPCA function disabled. It starts transmitting Beacon frames on the primary channel of the 6 GHz BSS to notify surrounding STAs of its presence. The control unit 302 cooperates with each unit to generate a Beacon frame including an information element in which a subfield indicating NPCA capability is set to "0," indicating that NPCA is not supported or is disabled, and transmits the frame on the primary channel of the 6 GHz band. This information element can be included in the UHR PHY Capabilities Element.

[0063] In S711, the control unit 302 starts providing a 6 GHz BSS with the NPCA function enabled. It starts transmitting Beacon frames on the primary channel of the 6 GHz BSS to notify surrounding STAs of its presence. The control unit 302 cooperates with each unit to generate a Beacon frame including an information element in which a subfield indicating NPCA capability is set to "1," indicating that NPCA is supported, and transmits the frame on the primary channel of the 6 GHz band. This information element can be included in the UHR PHY Capabilities Element. The Beacon frame can also include information for identifying the SPCH to which the transition will be made, as described above.

[0064] Next, connection control of STAs 102 to 103 connecting to an AP such as AP 101 will be described with reference to Fig. 8. In S801, the control unit 302 of STA 102 or STA 103 transmits a connection request to the AP. In S802, the control unit 302 determines whether the connection destination is a 2.4 GHz band network. If it is determined that the connection destination is a 2.4 GHz band network, the process proceeds to S803, and if it is determined that the connection destination is not a 2.4 GHz band network, the process proceeds to S804.

[0065] In S803, the control unit 302 configures communication parameters with the 2.4 GHz band AP so that the NPCA function is not used in communications addressed to the 2.4 GHz band network, regardless of whether the AP supports the NPCA function.The control unit 302 then controls communication with the 2.4 GHz band AP based on the configured communication parameters.This process allows the STA to operate without using the NPCA function when connected to the 2.4 GHz band AP, even if the destination AP declares support for the NPCA function in the 2.4 GHz band and the STA itself also supports the NPCA function.

[0066] In S804, the control unit 302 determines whether the NPCA function is supported in the network of the connected 5 GHz band or 6 GHz band AP. If it is determined that the NPCA function is supported, the process proceeds to S805. If it is determined that the NPCA function is not supported or is disabled, the process proceeds to S806. This determination may be made based on the value of a subfield indicating the NPCA capability of the UHR PHY Capabilities Element included in a Beacon received from the connected 5 GHz band or 6 GHz band AP. Specifically, the control unit 302 determines that the NPCA function is supported if "1" is set in the subfield. Furthermore, the control unit 302 determines that the NPCA function is not supported or is disabled if "0" is set in the subfield.

[0067] In S805, the control unit 302 cooperates with each unit to perform control so that the NPCA function is utilized in communications directed to the BSS of the destination 5 GHz or 6 GHz band AP. The control unit 302 configures communication parameters with the destination 5 GHz or 6 GHz band AP to utilize the NPCA function in communications directed to the network of the destination 5 GHz or 6 GHz band AP, and starts communication with the destination AP. Meanwhile, in S806, the control unit 302 performs control so that the NPCA function is not utilized in communications directed to the BSS of the destination 5 GHz or 6 GHz band AP. The control unit 302 configures communication parameters with the destination 5 GHz or 6 GHz band AP to not utilize the NPCA function in communications directed to the network of the destination 5 GHz or 6 GHz band AP, and starts communication with the destination AP. The above-described control allows the NPCA function to be utilized if the destination 5 GHz or 6 GHz band AP intends to use NPCA.

[0068] Finally, channel access using SPCH will be explained with reference to FIG.

[0069] In S901, the execution unit 503 of the AP or STA determines whether transmission data has been stored in the corresponding transmission queue. If it is determined that transmission data has been stored, the process proceeds to S902. If it is determined that transmission data has not been stored, the process waits for the transmission data to be stored. Note that the storage of data in the transmission queue is performed appropriately by an upper layer (not shown). For example, when a video distribution application or the like starts video distribution, the categorization unit 501 categorizes data corresponding to video data obtained from a camera provided in an STA such as STA102 or STA103 as VI and stores it in the VI queue. Also, when audio data is transmitted using a VoIP application or the like, the categorization unit 501 categorizes data corresponding to the audio data as VO and stores it in the VO queue. Note that, for IP packets addressed to an STA received from a wired network or the like, the AP 101 categorizes the data into one of the ACs based on an IP precedence value that manages the QoS of the IP packets. The determination process of S901 is performed in parallel by the execution units 503 corresponding to each queue.

[0070] In S902, the execution unit 503, which has determined in S901 that transmission data has been stored, acquires EDCA parameters corresponding to the access category of the queue associated with the execution unit from the control unit 504. Next, the execution unit 503 determines backoff parameters consisting of AIFS and a backoff value indicated by the backoff counter based on the acquired EDCA parameters, and sets the determined backoff parameters. Once the setting is complete, the process proceeds to S903. The backoff counter is determined so as to have randomness within the range of the current contention window size (CWsize) and aCWmin corresponding to the access category. aCWmin stands for adaptive contention window minimum. The initial value of CWsize (i.e., the CWsize used when no collision occurs) is aCWmin. The CWsize is doubled each time a collision occurs. In other words, in an environment where collisions frequently occur, the range of candidates for random backoff is expanded, thereby suppressing the occurrence of collisions. That is, the execution unit 503 calculates a back-off counter to be used by calculating aCWmin corresponding to the access category, which is a set of EDCA parameters, and a random number within the range of the current contention window size (CWsize).

[0071] In S903, the execution unit 503 executes a standby process for a transmission waiting time corresponding to an AIFS or a decrement process of the back-off counter on the condition that the channel state notified from the control unit 504 is an idle state. First, a standby process for a transmission waiting time corresponding to an AIFS is executed, and when the transmission waiting time corresponding to an AIFS becomes zero, a decrement process of the back-off counter is executed.

[0072] In S904, the execution unit 503 determines whether the backoff counter has reached 0. If it is determined that the backoff counter has reached 0, the process proceeds to S908, and if it is not determined that the backoff counter has reached 0 (i.e., if the backoff counter is 1 or greater), the process proceeds to S905.

[0073] In S905, the control unit 504 determines whether another terminal (another communication device) has acquired a transmission opportunity. The control unit 504, in cooperation with each unit, performs carrier sense on the PCH. When the PCH changes from an idle state to a busy state, the control unit 504 analyzes the signal received on the PCH and attempts to analyze the preamble of the PPDU. If the control unit 504 analyzes the preamble and determines that another communication device has acquired a transmission opportunity, the process proceeds to S906. On the other hand, if the PCH is still in the idle state and it is determined that another communication device has not acquired a transmission opportunity, the process proceeds to S903. Note that, although not shown in FIG. 5, if the control unit 202 of the AP 101 or the STAs 102-103 analyzes the preamble and determines that the received PPDU is addressed to itself, it performs control to receive the PPDU as appropriate.

[0074] In S906, the control unit 504 sets PCH_NAV, which indicates a period during which the device itself will not transmit on the PCH, based on information such as the Duration field of the PPDU received in S905. Subsequently, the control unit 504 notifies the execution unit 503 of a transition notification indicating transition to the PSCH. Upon receiving the transition notification, the execution unit 503 temporarily stores the current back-off parameters, which indicate the transmission waiting time managed to acquire a transmission opportunity on the PCH, as back-off parameters before the PSCH transition. The back-off parameters before the transition can be used as appropriate when controlling re-transition, which will be described later.

[0075] In S907, the control unit 202 transitions to the SPCH and attempts channel access and transmission on the SPCH. Specifically, the AP or STA identifies the channel to be accessed and switches to the SPCH based on information identifying the SPCH to which the NPCA function will be transitioned, which is broadcast to the surrounding area based on a Beacon frame or the like. Then, the AP or STA calculates back-off parameters for data transmission on the SPCH and decrements the back-off parameters. Then, when the back-off counter constituting the back-off parameters reaches zero, the AP or STA attempts data transmission using at least one channel that includes the SPCH but does not include the primary channel. If the transmission opportunity is successful, data transmission in UHR PPDU format is performed. The EDCA parameters used to calculate the back-off parameters on the SPCH may be the same as or different from the EDCA parameters for the primary channel. When the control unit 202 determines that the time during which the PCH_NAV is set has elapsed, the control unit 202 cooperates with the other units to re-transition from the SPCH to the PCH. After the re-transition is complete, the control unit 202 returns to S901. The back-off parameters in the PCH after the re-transition may be the back-off parameters temporarily stored before the transition, or may be recalculated.

[0076] Next, the transmission control of the PCH will be explained using S908 and subsequent steps. When the execution unit 503 determines that the back-off counter has reached zero, it requests the control unit 504 to transmit the data stored in the corresponding queue in S908. Upon receiving the request, the control unit 504 cooperates with the other units to transmit data in UHR PPDU format over one or more channels including at least the PCH.

[0077] In S909, the control unit 504 determines whether a collision has occurred due to the execution of data transmission. If it is determined that a collision has occurred due to the execution of data transmission, the process proceeds to S911, and if it is determined that a collision has not occurred, the process proceeds to S910.

[0078] In S911, the control unit 504 notifies the execution unit 503, which requested transmission of the data that was the subject of the collision, of the occurrence of a collision. Upon receiving the notification of the occurrence of a collision, the execution unit 503 increases the CWsize. Specifically, the execution unit 503 changes the CWsize to twice the current size.

[0079] In S910, the control unit 504 notifies the execution unit that requested the data transmission of the success of the data transmission. Upon receiving the notification of the success of the data transmission, the execution unit 503 initializes CWsize to aCWmin.

[0080] In S912, the control unit 202 determines whether to turn off the power. If it determines that a user operation to turn off the power has been received, it performs a shutdown process (not shown) and ends the series of transmission control. If it determines that a user operation to turn off the power has not been received, it proceeds to S901 and attempts to control further data transmission.

[0081] When both the 5 GHz band AP and the 6 GHz band AP and the STA support the NPCA function, the efficiency of frequency usage can be improved by controlling the NPCA function described above.

[0082] <Second embodiment> In the first embodiment, a mechanism for controlling the use of the NPCA function in the 2.4 GHz band was described. In the second embodiment, a mechanism for further restricting the use of the NPCA function in the 5 GHz band will be described. FIG. 10 is a schematic diagram illustrating channels and subbands in the 5 GHz band. As shown in FIG. 10, this band is divided into several subbands, respectively called W52, W53, W56, and W58. These subbands have different available frequencies and regulations. W53 and W56 are also called DFS bands. DFS (Dynamic Frequency Selection) is an interference suppression function that dynamically selects a channel to be used by a wireless device when interference with other communication systems such as a radar system is detected. This function is used to avoid interference because part of the 5 GHz band is shared with radar systems (such as weather radar and military radar). W58 is a subband that cannot be used in Japan due to legal restrictions but can be used in the United States and other countries. The DFS function requires that the channel must be changed immediately after detecting a radar signal, and that before switching to a new channel, the channel must be monitored for a certain period of time to ensure that the new channel is available. This period of monitoring is also called a channel availability check.

[0083] On the other hand, the NPCA function of the first embodiment and this embodiment assumes that a BSS is provided in a band combining a PCH and one or more secondary channels adjacent to the PCH, and that one of the secondary channels within this band is used as an SPCH. Therefore, if a BSS is provided in a DFS band channel such as W53 or W56, the SPCH to which NPCA transitions is also a DFS band channel. Considering that a channel availability check is required as a DFS requirement, a channel availability check may also be required before transitioning to an SPCH and attempting transmission. For example, in Japan, a channel availability check is required for one minute. This is much longer than the period of a transmission opportunity secured by an OBSS at one time. Therefore, using the NPCA function in a DFS band BSS is inefficient. In light of this, the second embodiment provides a mechanism for controlling the NPCA function not to be used when a DFS band BSS is provided or when connected to a DFS band BSS. The hardware and software configurations of the AP 101 and the STAs 102 and 103 are the same as those in the first embodiment, and therefore will not be described here. Specific control will be described using the flowcharts of Fig. 10 and Fig. 11. Fig. 10 shows an example of processing executed by the AP 101 in place of the flowchart of Fig. 7, and Fig. 11 shows an example of processing executed by the STAs 102 and 103 in place of the flowchart of Fig. 8. The execution entities and the like are the same as those in the first embodiment.

[0084] The difference between Fig. 11 and Fig. 7 is that if the result in S705 in Fig. 7 is No, that is, if it is determined that a 5 GHz band BSS is provided and the 5 GHz band NPCA function is enabled, an additional determination is made. The processing in S1101 to S1104 is the same as the processing in S701 to S704 in Fig. 7, and therefore a description thereof will be omitted.

[0085] In S1104, the control unit 302 determines whether the operation setting for providing a BSS in the 5 GHz band is set based on the acquired operation setting. If the control unit 302 determines that the operation setting for providing a BSS in the 5 GHz band is set, the process proceeds to S1105, and if the control unit 302 determines that the operation setting for providing a BSS in the 5 GHz band is set, the process proceeds to S1120.

[0086] In S1120, the control unit 302 determines whether the channel providing the BSS belongs to W53 or W56. If it is determined that the channel providing the BSS belongs to W53 or W56, the process proceeds to S1106. If it is determined that the channel providing the BSS does not belong to W53 or W56, the process proceeds to S1107. In S1106, the control unit 302 performs pre-operation monitoring and then starts providing the BSS in the 5 GHz band with the NPCA function disabled. The subsequent startup process shown in S1107 to S1111 is similar to S707 to S711 in FIG. 7, and therefore description thereof will be omitted. Note that if the user has set the operation to automatically select a channel and has also set the NPCA function to be used, the channel may be determined so as not to be a channel of W53 / W56. In this case, the startup process of S1107 may be performed on the determined channel. For example, the AP 101 may start a process of providing a BSS in which the NPCA function is enabled and in which any one of 36, 40, 44, and 48 of W52 is used as the PCH.

[0087] Next, connection control on the STA side will be explained using Fig. 12. The difference between Fig. 12 and Fig. 8 is that if the result of S802 in Fig. 8 is No, i.e., if the connection destination is a BSS in the 5 GHz band or 6 GHz band, two additional processes are performed: a determination process in S1211 and NPCA usage suppression control in S1212. In S1201, the control unit 302 of STA102 or STA103 transmits a connection request to the AP. In S1202, if the control unit 302 determines that the connection destination is a 2.4 GHz network, the process proceeds to S1203, and if the control unit 302 determines that the connection destination is not a 2.4 GHz network, the process proceeds to S1211.

[0088] In S1211, the control unit 302 determines whether the destination BSS is a DFS band network. If it is determined that the destination BSS is a DFS band network, the process proceeds to S1212; if it is determined that the destination BSS is not a DFS band network, the process proceeds to S1204. In S1212, the control unit 302 configures communication parameters with a DFS band AP so that the NPCA function is not used in communications addressed to the DFS band network, regardless of whether the AP supports the NPCA function, and controls communication with the DFS band AP. The processes of S1203 to S1206 are similar to the processes of S803 to S806, and therefore description thereof will be omitted. Through the above processes, even if an AP operating in the destination DFS band declares support for the NPCA function and the STA itself also supports the NPCA function, the STA can operate without using the NPCA function.

[0089] <Third embodiment> In the first and second embodiments, a mechanism for controlling not to use the NPCA function in frequency bands where there is a risk that an improvement in spectral efficiency is not expected has been described. In this embodiment, the use of the NPCA function is not significantly restricted, but a mechanism is provided in which, as an initial setting at the time of shipment from the factory, the initial value of the user setting for whether to disable or enable the NPCA function is different for frequency bands where an improvement in spectral efficiency is not expected and frequency bands where an improvement in spectral efficiency is expected. In the third embodiment, the use of the NPCA function only in the DFS band is prohibited, while the use of NPCA itself in other bands can be changed according to the user's preference.

[0090] Figures 13(A) and (B) are diagrams showing examples of the initial setting DB 304a described in Figure 3. Figure 13(A) shows an example of initial setting values ​​in list format that are common regardless of country or destination region, and Figure 13(B) shows an example of location-dependent initial setting values ​​in list format that differ for each country or region depending on the country or destination information written at the time of shipment from the factory.

[0091] The setting value corresponding to the setting item "Model Name" stores the model number of the AP 101, etc. The setting value corresponding to the setting item "Country / Region" stores information indicating the country / region required for referencing FIG. 13(B). FIG. 13(A) illustrates an example in which the JP destination is written at the time of factory shipment. Other country / region information such as US, EP, and CN can be written at the time of factory shipment or production. Next, usage settings such as whether to provide a BSS in each band, and detailed settings such as the SSID, authentication method, and operating channel of the BSS for each band are stored. In this embodiment, an initial setting indicating whether to enable or disable the use of the NPCA function for each band is stored. In this embodiment, the initial setting DB 304a uses OFF (disabled) as the initial value of the NPCA function in the 2.4 GHz band. In addition, the initial setting DB 304a uses ON (enabled) as the initial value of the NPCA function in the 6 GHz band.

[0092] The initial values ​​of the NPCA function for the 5 GHz band are stored in location-dependent initial settings so that they can be varied based on the country / region information written at the time of shipment. As shown in Figure 13(B), because legal regulations for the 5 GHz band vary from country to country, available frequency information is managed for each country. The AP 101 and STAs 102-103 acquire the setting values ​​corresponding to the country / region illustrated in Figure 13(A). The AP 101 then references the location-dependent legal frequency information (5 GHz) corresponding to the acquired setting values, illustrated in Figure 13(B), and controls the provision of a BSS within the range of that frequency information. Furthermore, if AutoSelect is selected as the user setting for the 5 GHz channel, the AP 101 determines a channel within the frequency range supported by the country / region. Furthermore, the change screen for changing the user settings also displays a display item (e.g., a drop-down list) for specifying an operating channel within the frequency range supported by the country / region. The initial values ​​of the NPCA function for the 5 GHz band are also stored in Figure 13(B). As shown in Figure 13(B), for AP101 with the country / region set to US or CN as the default, the default value of the NPCA function in the 5 GHz band is ON. In countries where the subband classified as W58 is available, there are many channels that do not require radar checks using the DFS function. In this case, since APs physically located in the vicinity operate on various channels, the density of APs on each channel is expected to be more dispersed than in countries where the subband classified as W58 is not available. Therefore, these default values ​​are set assuming that using the NPCA function will improve frequency utilization efficiency. On the other hand, for AP101 with the country / region set to JP or CN as the default, the default value of the NPCA function in the 5 GHz band is OFF. In countries where the subband classified as W58 is not available, there are fewer channels that do not require radar checks using the DFS function compared to the US and EP. Therefore, these default values ​​are set assuming that using the NPCA function will not improve frequency utilization efficiency.

[0093] Next, a setting screen provided to the user by the AP 101 in this embodiment will be described with reference to Fig. 14. Fig. 14 is an example of a setting screen provided to the user by the AP 101. The user can change various operation settings by selecting each display item displayed on the screen of Fig. 14. As described above, the setting screen provided by the UI control unit 305 and the maintenance screen described in Fig. 15 are provided via the output unit 205 or as web content. When providing a setting screen as web content, the setting screen is provided on the web browser of the STA by providing web content corresponding to the setting screen to the STA, as described above.

[0094] Display item 1401 is a checkbox for selecting whether to enable or disable the use of the NPCA function in the 2.4 GHz band. By selecting display item 1401, the user can change the operation setting for whether to use the NPCA function as a user setting. Display item 1402 is a message informing the user that use of NPCA operation in the 2.4 GHz band is not recommended. Displaying this message can prevent users who are not familiar with wireless network technology from inadvertently changing the setting to enable NPCA operation in the 2.4 GHz band.

[0095] Display item 1411 is a display item such as a checkbox for selecting whether to enable or disable the use of the NPCA function in the 5 GHz band. By selecting display item 1421, the user can change the user-defined operational setting for whether to use the NPCA function in the 5 GHz band. Display item 1412 displays a message informing the user that the NPCA function cannot be used when a DFS band channel is specified. Finally, display item 1421 is a checkbox for selecting whether to enable or disable the use of the NPCA function in the 6 GHz band. By selecting display item 1401, the user can change the user-defined operational setting for whether to use the NPCA function. A note message regarding the use of the NPCA function is not displayed around this display item 1421. The factory default setting for display item 1421 is set to ON (enabled). Therefore, in the 6 GHz band, where the NPCA function is expected to improve frequency utilization efficiency, the user can enjoy the NPCA function without changing the settings. The other display items are for changing other BSS-specific settings such as SSID and channel. The user can change the BSS settings as needed by operating other display items.

[0096] 14, the UI control unit 305 identifies the target of the setting change and its setting value, and requests the setting change from the setting management unit 304. The management unit 304 updates the operational setting DB 304b of the communication device based on the request.

[0097] Next, a maintenance screen provided to the user by the AP 101 in this embodiment will be described with reference to FIG. 15 . FIG. 15 is an example of a maintenance screen provided to the user by the AP 101. The user can initialize the setting values ​​by selecting each display item displayed on the screen of FIG. 15 . Display item 1501 is a key used to restore the operation settings of the AP 101 to the factory default settings. The user can issue an initialization instruction to the AP 101 by selecting display item 1501. When the control unit 305 detects information indicating that the key has been selected from the input unit 204 or detects that an operation to select the key has been performed based on an HTTP request from an STA, the control unit 305 executes the reset control of the setting values ​​described above. When the reset control is executed, the setting values ​​in the operation setting DB 304b are overwritten with the initial values ​​described in FIGS. 13(A) and 13(B). Therefore, the NPCA function usage settings that take frequency utilization efficiency into consideration can be initialized with a single touch, improving user convenience.

[0098] Specific reset control will be described with reference to Fig. 16. Each process shown in the flowchart of Fig. 16 is executed by the processor of the control unit 202 of the AP 101 executing a computer program stored in the storage unit 201. Note that some processes, such as transmission and modulation, are realized in cooperation with the processor of the control unit 202 and various processors, ASICs, DSPs, FPGAs, etc. that constitute the communication unit 206, as well as the ASICs, DSPs, FPGAs, etc. that constitute the antenna and control unit 202. Note that when it is necessary to clearly indicate the subject of processing, the functional units described in Figs. 3 and 5 will be used as the subject in the description. Note that the control in Fig. 16 shows an excerpt of the control when a setting screen or maintenance screen is presented to the user and operations are accepted.

[0099] In S1601, the UI control unit 305 determines whether an operation to initialize the settings has been performed. If it is determined that an operation to initialize the settings has been performed, the process proceeds to S1602. If it is determined that an operation to initialize the settings has not been performed, the process proceeds to S1604. For example, the initialization operation is an operation of selecting display item 1501 displayed on the maintenance screen described in FIG. 15. Note that this is not limited to this. A modified example will be described with reference to FIG. 17. FIG. 17 is a diagram for explaining another example of an initialization operation and shows an external view of the AP 101. A hardware button 1700 for performing easy setup such as WPS (registered trademark) and an LED indicating the connection status, etc. are arranged on the front side. LED stands for Light Emitting Diode. WPS stands for Wi-Fi (registered trademark) Protected Setup. A hardware reset button 1701, which is also a hardware button, is arranged on the back side. Button 1700 is configured to be easily activated by pressing it with a user's finger, but button 1701 is located inside a small hole to prevent accidental resetting to factory settings. Controller 305 can also determine that an operation to initialize settings has been performed when it detects that the user has pressed and held button 1701 inside the small hole for several seconds. A user can access button 1701 using a SIM card eject pin or the like shown in FIG. 17. An operation of pressing and holding button 1701 or an operation of selecting display item 1501 are examples of predetermined user operations.

[0100] In S1602, the UI control unit 305 acquires country / region information from the DB managed by the management unit 304, and acquires location-dependent initial settings corresponding to the country / region information from the initial setting DB 304a. In S1603, the UI control unit 305 acquires common initial settings that are not dependent on the country / region from the initial setting DB 304a managed by the management unit 304, and overwrites the setting values ​​in the operation setting DB 304b based on the acquired common initial settings and the location-dependent initial settings. This processing makes it possible to reset to the initial setting value group configured at the time of shipment from the factory / manufacturing. Once the processing is complete, the system waits for other user operations. Note that a configuration may be made in which a reboot process of the AP 101 is performed upon resetting.

[0101] Next, in S1604, the control unit 305 determines whether an operation to end the setting process has been performed. For example, if an operation to close the setting process screen has been received, the control unit 305 determines that an operation to end the setting process has been performed. Also, if the setting screen is presented after the administrator's user ID and password have been input and authenticated, the control unit 305 can determine that an operation to end the setting process has been performed in the following cases. Specifically, if an operation to log out via the setting screen or maintenance screen has been received, or when a user with administrator privileges is logged out due to a timeout or the like, the control unit 305 determines that an operation to close the setting process screen has been received. If the control unit 305 determines that an operation to end the setting process has been performed, the control unit 305 ends the series of processes. On the other hand, if the control unit 305 determines that an operation to end the setting process has not been performed, the control unit 305 advances the process to S1605.

[0102] In S1605, the control unit 305 performs processing for updating settings based on other user operations, such as changing the SSID or changing whether the NPCA function is available, and updates each operation setting.

[0103] Through the processing described above, it becomes possible to ship the AP 101 in a state where the operation settings are configured so that the NPCA function is used in frequency bands where the NPCA function estimates that the frequency utilization efficiency is high, and the NPCA function is not used in frequency bands where the frequency utilization efficiency is not high, at the time of factory shipment. Also, when an initialization operation is accepted, it becomes possible to reset the operation settings to a state where the NPCA function is used in frequency bands where the NPCA function estimates that the frequency utilization efficiency is high, and the NPCA function is not used in frequency bands where the frequency utilization efficiency is low.

[0104] <Modification> In the second embodiment described above, an example was given of a case where control is performed to prohibit the use of the NPCA function in the 5 GHz DFS band. This control can also be modified to uniformly prohibit the use of the NPCA function in the 5 GHz band. In this case, the AP 101 provides a BSS that allows the NPCA function to be used only in the 6 GHz BSS. In this case, the STAs 102 to 103 can be controlled to use the NPCA function only when connecting to the 6 GHz BSS, and not to use the NPCA function when the connecting BSS is a 2.4 GHz or 5 GHz BSS.

[0105] <Other embodiment 1> The disclosure of this embodiment also includes the following configuration.

[0106] (Configuration 1) A communication device that supports a function of attempting to acquire a transmission opportunity and transmit data on a non-primary channel different from the primary channel when another communication device acquires a transmission opportunity on the primary channel on which data is to be transmitted, A communication device characterized by having a communication control means that, when communicating in a 2.4 GHz band network, controls the device so that it does not attempt to obtain a transmission opportunity in a non-primary channel using the function, even if another communication device has obtained a transmission opportunity in the primary channel of the 2.4 GHz band network.

[0107] (Configuration 2) The communication device according to configuration 1, characterized in that when communicating in a 6 GHz band network and the use of the function is permitted in the 6 GHz band network, when another communication device acquires a transmission opportunity in a primary channel of the 6 GHz band network, the communication control means attempts to acquire a transmission opportunity in a non-primary channel using the function.

[0108] (Configuration 3) The communication device according to configuration 1 or 2, wherein when communicating in a 5 GHz band network and the primary channel of the 5 GHz band network is a DFS band channel, the communication control means controls the communication device so that the communication device does not attempt to acquire a transmission opportunity on a non-primary channel using the function, even if another communication device has acquired a transmission opportunity on the primary channel in the DFS band.

[0109] (Configuration 4) 4. The communication device according to any one of configurations 1 to 3, wherein the communication device is an access point device.

[0110] (Configuration 5) 4. The communication device according to any one of configurations 1 to 3, wherein the communication device is a station device.

[0111] (Configuration 6) A communication device that supports a function of attempting to acquire a transmission opportunity in a non-primary channel different from the primary channel and transmit the data when another communication device acquires a transmission opportunity in the primary channel on which data is to be transmitted, a storage means for storing initial setting information of the communication device; A communication device characterized in that the initial setting information stored in the storage means is initial setting information that is set so that at least the function is not used as an operational setting for a 2.4 GHz band network, and is set so that at least the function is used as an operational setting for a 6 GHz band network.

[0112] (Configuration 7) 7. The communication device according to configuration 6, further comprising reset means for resetting operation settings of the communication device based on the initial setting information after receiving a predetermined user operation.

[0113] (Configuration 8) The communication device according to configuration 7, wherein the predetermined user operation is a user operation of selecting a display item for accepting an operation to reset the operation settings of the communication device to the factory default settings.

[0114] (Configuration 9) 9. The communication device according to configuration 8, wherein the predetermined user operation is a user operation of pressing and holding a hardware reset button.

[0115] (Configuration 10) A control method for a communication device that supports a function of attempting to acquire a transmission opportunity and transmit data on a non-primary channel different from the primary channel when another communication device acquires a transmission opportunity on the primary channel on which data is to be transmitted, comprising: a communication control step of controlling a communication device so that, when communicating in a 2.4 GHz band network, the communication device does not attempt to acquire a transmission opportunity in a non-primary channel using the function, even if another communication device has acquired a transmission opportunity in the primary channel of the 2.4 GHz band network.

[0116] (Configuration 11) 11. A program for causing a computer to execute the method for controlling a communication device according to claim 10.

[0117] <Other embodiment 2> 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.

[0118] 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]

[0119] 101 AP 102 Station 103 STA 201 Control Unit

Claims

1. A communication device that supports a function of attempting to acquire a transmission opportunity and transmit data on a non-primary channel different from the primary channel when another communication device acquires a transmission opportunity on the primary channel on which data is to be transmitted, A communication device characterized by having a communication control means that, when communicating in a 2.4 GHz band network, controls the device so that it does not attempt to obtain a transmission opportunity in a non-primary channel using the function, even if another communication device has obtained a transmission opportunity in the primary channel of the 2.4 GHz band network.

2. The communication device according to claim 1, characterized in that when communication is performed in a 6 GHz band network and use of the function is permitted in the 6 GHz band network, when another communication device acquires a transmission opportunity in a primary channel of the 6 GHz band network, the communication control means attempts to acquire a transmission opportunity in a non-primary channel using the function.

3. The communication device described in claim 2, characterized in that when communication is performed in a 5 GHz band network and the primary channel of the 5 GHz band network is a DFS band channel, the communication control means controls the device so that it does not attempt to obtain a transmission opportunity on a non-primary channel using the function, even if another communication device has obtained a transmission opportunity on the primary channel in the DFS band.

4. 4. The communication device according to claim 1, wherein the communication device is an access point device.

5. 4. The communication device according to claim 1, wherein the communication device is a station device.

6. A communication device that supports a function of attempting to acquire a transmission opportunity in a non-primary channel different from the primary channel and transmit the data when another communication device acquires a transmission opportunity in the primary channel on which data is to be transmitted, a storage means for storing initial setting information of the communication device; A communication device characterized in that the initial setting information stored in the memory means is initial setting information that is set so that at least the function is not used as an operational setting for a 2.4 GHz band network, and is set so that at least the function is used as an operational setting for a 6 GHz band network.

7. 7. The communication device according to claim 6, further comprising a reset unit that resets operation settings of the communication device based on the initial setting information after receiving a predetermined user operation.

8. 8. The communication device according to claim 7, wherein the predetermined user operation is a user operation of selecting a display item for accepting an operation to reset the operation settings of the communication device to the factory settings.

9. The communication device according to claim 8 , wherein the predetermined user operation is a user operation of pressing and holding a hardware reset button.

10. A control method for a communication device that supports a function of attempting to acquire a transmission opportunity and transmit data on a non-primary channel different from the primary channel when another communication device acquires a transmission opportunity on the primary channel on which data is to be transmitted, comprising: a communication control step of controlling a communication device so that, when communicating in a 2.4 GHz band network, the communication device does not attempt to acquire a transmission opportunity in a non-primary channel using the function, even if another communication device has acquired a transmission opportunity in the primary channel of the 2.4 GHz band network.

11. A program for causing a computer to execute the communication device control method according to claim 10.

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