Communication device, communication method, and program

Abstract

To provide a communication device which more effectively utilizes frequency resources in a communication system consisting of a plurality of channels and using a communication link, a method and a program.SOLUTION: A communication device communicates with a first other communication device using any one of a first communication system using a first channel and a second communication system not using the first channel but using one or more second channels in one communication link which constructs a first network and consists of a first channel and one or more second channels different from the first channel, receives a radio frame relating to the occupation of one or more channels including the first channel from a second other communication device constructing a second network different from the first network and, in a case where the one or more channels including the first channel are occupied in the second network, transmits to the first other communication device a notification instructing whether the second communication system should be used or the transmission of the radio frame is inhibited.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a communication technique in a communication device capable of communicating using a communication link made up of a plurality of channels. [Background technology]

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

[0003] As one of the candidate technologies to be included in the IEEE802.11bn standard, a technology for efficiently using frequency resources in a communication method 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 cannot be used. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 1,169,6353 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a technique for enabling more efficient utilization of frequency resources in a communication system using a communication link consisting of multiple channels. [Means for solving the problem]

[0006] A communication device according to one embodiment of the present invention is a communication device that communicates in accordance with the IEEE 802.11 standard series, and has a communication means for communicating with a first other communication device belonging to the first network using either a first communication method that uses at least the first channel or a second communication method that uses one or more of the second channels without using the first channel, in a single communication link consisting of a first channel used to construct a first network and acquire transmission rights and one or more second channels different from the first channel, and the communication means receives a wireless frame regarding occupancy of one or more channels including the first channel from a second other communication device that constructs a second network different from the first network, and when one or more channels including the first channel are occupied in the second network, transmits a notification to the first other communication device instructing it to use the second communication method or instructing the prohibition of transmission of wireless frames. Effect of the Invention

[0007] According to the present invention, it is possible to more efficiently utilize frequency resources in a communication system using a communication link made up of multiple channels. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Diagram 2]1 is a schematic diagram illustrating an example of a time chart when a communication device transmits data. [Diagram 3] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Figure 4] FIG. 2 illustrates an example of a functional configuration of a communication device. [Diagram 5] FIG. 1 is a diagram illustrating an example of a communication flow in a wireless communication system. [Figure 6] FIG. 11 illustrates an example of a flow of processing executed by an AP. [Figure 7] FIG. 11 illustrates an example of a flow of processing executed by an AP. [Figure 8] FIG. 11 illustrates an example of a flow of processing executed by an AP. [Figure 9] FIG. 11 illustrates an example of a flow of processing executed by an AP. [Figure 10] FIG. 11 is a diagram illustrating an example of a flow of processing executed by a STA. [Figure 11] FIG. 11 is a diagram illustrating an example of a flow of processing executed by a STA. [Figure 12] FIG. 11 is a diagram illustrating an example of a flow of processing executed by a STA. [Figure 13] FIG. 11 is a diagram illustrating an example of a flow of processing executed by a STA. [Figure 14] FIG. 11 is a diagram showing another example of a communication flow in a wireless communication system. [Figure 15] FIG. 13 is a diagram illustrating a modified example of the flow of processing executed by the AP. [Figure 16] FIG. 13 is a diagram illustrating a modified example of the flow of processing executed by the AP. [Figure 17] FIG. 13 is a diagram illustrating a modified example of the flow of processing executed by the AP. [Figure 18] FIG. 13 is a diagram illustrating a modified example of the flow of processing executed by the AP. [Figure 19] FIG. 13 is a diagram showing a modified example of the flow of processing executed by the STA. [Figure 20] FIG. 13 is a diagram showing a modified example of the flow of processing executed by the STA. [Figure 21] FIG. 13 is a diagram showing a modified example of the flow of processing executed by the STA. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] (System Configuration) FIG. 1 shows an example of the configuration of a wireless communication system according to this embodiment. The wireless communication system includes, for example, an access point (AP101) and a station (STA102). The AP101 and the STA102 are communication devices capable of performing wireless communication conforming to the IEEE802.11 standard series. In this embodiment, when there is no need to distinguish between the AP101 and the STA102, they may be collectively referred to as communication devices. IEEE is an abbreviation for the Institute of Electrical and Electronics Engineers. FIG. 1 shows a configuration in which the STA102 participates in a network 103 constructed by the AP101. The network 103 may also be called a Basic Service Set (BSS). Note that FIG. 1 shows a state in which a network 113 composed of the AP111 and the STA112 exists in the vicinity of the network 103 composed of the AP101 and the STA102. The AP111 and the STA112 are communication devices capable of performing wireless communication conforming to the IEEE802.11 standard series, like the AP101 and the STA102. For AP101 and STA102, network 103 is a BSS to which the own device is connected, and may be called own BSS. On the other hand, for AP101 and STA102, network 113 is a network that may cause interference to the own BSS, and may be called overlapping BSS (OBSS). Note that, although an example in which one AP and one STA exist in each of the two networks is shown in FIG. 1, a plurality of APs and STAs may exist in one network. In addition, at that time, a plurality of STAs may be connected to one AP, and a single STA may be connected to a plurality of APs. Note that, in the following, the description will be focused on AP101 and STA102, but AP111 and STA112 may have the same functions.

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

[0012] A communication device may transmit and receive radio signals using frequency bands such as 2.4 GHz, 3.6 GHz, 5 GHz, and 6 GHz, as well as 45 GHz and 60 GHz bands, which are called millimeter waves. The frequency bands used by the communication device are not limited to these bands and may include, for example, the Sub 1 GHz band. The communication device may communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The bandwidths used by the communication device are not limited to these bands and may use, for example, bandwidths of 240 MHz and 4 MHz. In the IEEE 802.11 standard series, a frequency channel using a bandwidth of 20 MHz is specified as a basic channel in frequency bands such as 2.4 GHz, 5 GHz, and 6 GHz. In this standard, multiple available channels are defined in each of the 2.4 GHz, 5 GHz, and 6 GHz frequency bands. In this standard, a communication device may use a certain channel in combination with another adjacent channel. Such use of a channel in combination with another adjacent channel may be called channel bonding. A bundle of channels formed by one or two or more adjacent channels may be called a communication link. That is, one link formed by two channels with a bandwidth of 20 MHz may use a bandwidth of 40 MHz. In the IEEE802.11be standard, 320 MHz is expected to be specified as the maximum bandwidth available for one link. Furthermore, signals transmitted in this bandwidth may be continuous or discontinuous on the frequency axis. The AP 101 and the STA 102 may be AP MLD (Multi-Link Device) and STA MLD, respectively, that support Multi-Link, which establishes multiple links simultaneously to communicate.

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

[0014] For example, when a communication device communicates using a link with a bandwidth of 160 MHz, the communication device may determine whether or not transmission is possible using only a first channel with a bandwidth of 20 MHz included in the link. This first channel may be called a Primary Channel (PCH). For example, the IEEE 802.11 standard series describes that a communication device may start transmission if it determines that transmission is possible as a result of performing carrier sense on the PCH for a predetermined period of time. The predetermined period is determined by an Interframe Space (IFS) determined for each access category that classifies the type of communication traffic, and a random number (backoff counter) that is randomly determined from a predetermined range. That is, when the communication device determines that the PCH is in an idle state for this predetermined period of time, it acquires a transmission right to transmit using the link. At this time, if a second channel other than the PCH is in an idle state during a PIFS period immediately before the start of transmission, the communication device may perform transmission by channel bonding using the idle channel and the PCH. PIFS is an abbreviation for Priority Interframe Space. Furthermore, when a communication device determines that transmission is not possible as a result of performing carrier sensing on a PCH, the communication device may postpone transmission even if other channels included in the same link are in an idle state. Each second channel other than the PCH constituting one link may also be called a secondary channel (SCH) or a non-primary channel (NPCH).

[0015] In a communication device, when a signal is received on a certain channel, if a signal is transmitted on another channel (e.g., an adjacent channel) arranged at a frequency close to the channel, the received signal may not be properly received. For example, it is assumed that a communication device can simultaneously perform a transmission process and a reception process using different channels. When a communication device receives using a certain channel and transmits on an adjacent channel, the power of the transmission signal leaks into the channel of the received signal, causing interference with the received signal. In general, the power of such a leakage of the transmission signal is much greater than the received power of the received signal, so it is expected that the received signal cannot be properly received. In order to avoid such a situation, the IEEE802.11 standard series provides a mechanism for preventing another communication device from transmitting a signal to the communication device using a channel adjacent to the PCH while the communication device is transmitting a signal. That is, the PCH is provided as a channel commonly used between communication devices to determine whether transmission is possible, and it is stipulated that while one communication device is transmitting using the PCH, the other communication device will not transmit even if the other channel is in an idle state. As a result, while a communication device is transmitting a signal and the PCH is in use, other communication devices do not transmit signals using channels adjacent to the PCH, so that the communication device does not receive a signal on the adjacent channel. Therefore, the above-mentioned problem of interference caused by power leakage between channels can be solved.

[0016] However, not using other channels (NPCH) that are in an idle state based on the PCH being busy may hinder efficient use of frequency resources of the entire link. FIG. 2(A) shows an example of a time chart when STA102 transmits data to AP101. In FIG. 2(A), STA102 performs carrier sense on PCH, confirms that it is in an idle state, and then transmits data using PCH with a bandwidth of 20 MHz. In this case, for example, even if seven NPCHs other than PCH are in an idle state, other communication devices are not allowed to communicate using NPCH. Also, FIG. 2(B) shows another example of a time chart when STA102 transmits data to AP101. In FIG. 2(B), while STA102 is performing carrier sense on PCH, PCH is used by another network (for example, network 113 in FIG. 1) that exists in the geographical vicinity of STA102. In this case, since the PCH is determined to be busy in the carrier sense by the STA 102, even if the seven NPCHs other than the PCH are idle, the STA 102 is not permitted to communicate with the AP 101 using the NPCH. However, since the AP 101 is not transmitting at this time, even if the STA 102 transmits to the AP 101 using the NPCH, the AP 101 can properly receive the signal transmitted by the STA 102. In this way, if the PCH with a bandwidth of, for example, 20 MHz is used by another network, and the remaining NPCH with an idle bandwidth of 140 MHz is not used, the frequency resources cannot be used efficiently.

[0017] In this embodiment, in view of such circumstances, when a PCH is being used by another communication device, a function is provided for communication between communication devices using an NPCH included in the same link as the PCH without using the PCH. As an example, when the PCH is busy, the communication device sets a Secondary Primary Channel (SPCH) used to acquire a transmission right for transmission using the NPCH. The SPCH is one or more channels among the NPCH included in the same link as the PCH. When the communication device determines that the PCH is being used by another communication device, it subsequently determines whether transmission is possible in the SPCH. That is, the communication device performs the above-mentioned carrier sense in the SPCH, and determines that communication using the NPCH can be performed based on confirmation that the SPCH is in an idle state. Then, when the communication device determines that transmission is possible in the SPCH, it performs transmission using one or more NPCHs including the SPCH. In this embodiment, a communication method in which transmission is performed using one or more channels including the SPCH without using the PCH is called NPCH access (Non-Primary Channel Access). Note that this communication method may be called by other names. For example, this communication method may be called SCA (Secondary Channel Access). When the PCH is available, the communication device performs communication in a first communication method in which communication is performed in one communication link using the PCH and one or more NPCHs. On the other hand, the communication device is configured to be able to perform communication in a second communication method (NPCH access) when a certain further condition (e.g., the NPCH is not used) is satisfied, provided that the PCH is not available.

[0018] AP101 and STA102 may perform NPCH access when it is confirmed that the PCH is not in an idle state (used by the OBSS) as shown in FIG. 2(A). On the other hand, it is assumed that STA102 may be in a position where it cannot receive signals transmitted from AP111 or STA112 with sufficient power as shown in FIG. 1. If STA102 is in such a position, it cannot detect the use of PCH even if it is used by the OBSS. Therefore, STA102 may determine that PCH is not in use and attempt to transmit a signal using PCH, while AP101 may determine to use NPCH access by detecting a signal from AP111 or STA112. In other words, it is assumed that the determination results of whether or not to perform NPCH access will not be consistent between AP101 and STA102.

[0019] In this embodiment, in consideration of such circumstances, for example, the AP 111 transmits a wireless frame to a communication device of an OBSS (network 103) different from the BSS (network 113) that the AP 111 establishes, requesting the occupancy of a channel set as a PCH in the OBSS. This wireless frame requests that the network 113 established by the AP 111 occupy one or more channels including the channel used as the PCH of the network 103. Hereinafter, this wireless frame is called an occupancy request frame. Then, when the AP 101 receives this occupancy request frame, it determines whether or not to permit the occupancy of one or more channels including the PCH, and transmits a wireless frame including the result of the determination. This wireless frame is a response to the occupancy request frame, and is hereinafter called an occupancy response frame. The occupancy response frame does not necessarily have to be received by the AP 111, but is transmitted at least in response to the reception of the occupancy request frame. This occupancy response frame is received by a STA (e.g., STA 102) of the BSS (e.g., network 103) on the side where the occupancy of the PCH is requested. As a result, in the BSS for which occupancy of the PCH is requested, it is shared that NPCH access should be performed when communication is performed during a period in which the channel used as the PCH in that BSS is occupied by the OBSS (the BSS that requested occupancy). In one example, it is assumed that AP 101 is in a position where it can receive an occupancy request frame from AP 111, and STA 102 is unable to receive this occupancy request frame. When AP 101 receives this occupancy request frame, it transmits an occupancy response frame to the surrounding area. STA 102 recognizes from this occupancy response frame that the PCH is occupied by the OBSS (here, network 113), and is able to recognize that communication should be performed by NPCH access.

[0020] The configuration of a communication device that performs such processing and an example of the flow of the processing will be described in detail below.

[0021] (Device configuration) 3 shows an example of the hardware configuration of a communication device (AP101, AP111, STA102, and STA112). The communication device has a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 306, and an antenna 307. Note that these are only examples, and the communication device may have further configurations not shown in FIG. 3, and some or all of the configurations shown in FIG. 3 may be replaced with other configurations having similar functions.

[0022] The storage unit 301 includes one or more memories such as a ROM and a RAM. The storage unit 301 stores various information such as computer programs for performing various operations described below and communication parameters for wireless communication. ROM stands for Read Only Memory, and RAM stands for Random Access Memory. The storage unit 301 may include storage media such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, and a DVD, in addition to memories such as a ROM and a RAM. The storage unit 301 may include storage media such as a plurality of memories.

[0023] The control unit 302 includes one or more processors, such as a CPU or an MPU. The CPU stands for Central Processing Unit, and the MPU stands for Micro Processing Unit. The control unit 302 executes a computer program stored in the storage unit 301 to control the entire communication device. The control unit 302 may control the entire device in cooperation with the computer program stored in the storage unit 301 and an operating system. The control unit 302 generates data and signals (radio frames) to be transmitted in communication with other communication devices. The control unit 302 may include multiple processors, such as a multi-core processor, and the multiple processors may control the entire communication device.

[0024] Furthermore, the control unit 302 controls the functional unit 303 to execute predetermined processes such as wireless communication, image capture, printing, and projection. The functional unit 303 is configured to include hardware for the communication device to execute predetermined processes. When the communication device is a printer, the functional unit 303 is a printing device, and prints image data acquired via the communication unit 306, for example. When the communication device is a scanner, the functional unit 303 is a reading device, and outputs image data generated by scanning to the outside, for example, via the communication unit 306. When the communication device is a camera, the functional unit 303 is configured to include an image sensor and a lens, and outputs image data captured by the camera to the outside, for example, via the communication unit 306.

[0025] The input unit 304 includes, for example, a touch panel, hard keys, buttons, etc., and accepts various operations from the user. The output unit 305 includes a display, a speaker, etc., and performs various outputs to the user. Here, the output by the output unit 305 may be a screen display output on a display, or a voice output by a speaker. The output unit 305 may also include a vibrator, and may perform information output by vibration output. Note that both the input unit 304 and the output unit 305 may be implemented by one module, such as a touch panel display. Also, the input unit 304 and the output unit 305 may be built into the communication device, or may be implemented by an external input / output device. In this case, the communication device has an input / output interface for connecting to the input / output device.

[0026] The communication unit 306 executes control for performing wireless communication conforming to the IEEE802.11bn standard. In addition to the IEEE802.11bn standard, the communication unit 306 may also control wireless communication conforming to other IEEE802.11 standard series and wired communication such as wired LAN. The communication unit 306 controls the antenna 307 to transmit and receive signals for wireless communication generated by the control unit 302. For example, the communication device communicates data such as image data, document data, and video data with a partner device via the communication unit 306. Note that, if the communication device supports the NFC standard, Bluetooth standard, and the like in addition to the IEEE802.11bn standard, the communication unit 306 may control wireless communication conforming to these communication standards. In addition, if the communication device is capable of performing wireless communication conforming to a plurality of communication standards, a communication unit and an antenna corresponding to each of these communication standards may be provided separately.

[0027] The antenna 307 is, for example, an antenna capable of detecting and emitting radio waves in the 2.4 GHz band, the 5 GHz band, and the 6 GHz band. The antenna 307 may be configured to be capable of communication in the same frequency band. In this case, the antenna 307 may be, for example, a multi-band antenna capable of communication in multiple frequency bands. Although FIG. 3 shows an example in which the communication device has two antennas, one antenna may be used, or three or more antennas may be used. In addition, when the communication device has multiple antennas, it may have a communication unit 306 corresponding to each antenna. In addition, the antenna 307 may be prepared separately from the communication unit 306, or may be configured as one module together with the communication unit 306.

[0028] FIG. 4 is a block diagram showing an example of a functional configuration of a communication device (AP101, AP111, STA102, and STA112). The communication device includes, for example, a PCH communication control unit 401, an NPCH communication control unit 402, and a communication control unit 403. These functions can be implemented by, for example, executing a program stored in a storage unit 301 of the communication device by the control unit 302. However, this is an example, and dedicated hardware for implementing each function may be prepared. The configuration shown in FIG. 4 is an example, and the communication device may include configurations other than these configurations. Furthermore, two or more functional blocks in FIG. 4 may be implemented as one functional block, or one functional block may be divided into two or more functional blocks.

[0029] The PCH communication control unit 401 establishes one link using one or more channels including the PCH together with the STA to perform communication. For example, the PCH communication control unit 401 receives a wireless frame from a counterpart device connected to the own device that has acquired a transmission right in the PCH, or acquires a transmission right in the PCH and transmits a wireless frame to the counterpart device. The NPCH communication control unit 402 performs communication using the NPCH access when the PCH is used by another device and cannot be used. That is, the NPCH communication control unit 402 performs communication using the NPCH access when, for example, use of the PCH by the OBSS is detected, or when it is determined that NPCH access should be performed based on an occupancy request frame or an occupancy response frame described later. For example, the NPCH communication control unit 402 confirms that the SPCH is in an idle state, acquires a transmission right in the NPCH, and transmits a wireless frame using one or more NPCHs including the SPCH without using the PCH. The NPCH communication control unit 402 also receives a wireless frame transmitted by a counterpart device connected to the own device through the NPCH access. The communication control unit 403 controls whether to use the PCH communication control unit 401 or the NPCH communication control unit 402 for communication. For example, the communication control unit 403 determines whether the PCH is occupied by the OBSS based on an occupancy request frame or an occupancy response frame, and when the PCH is not occupied, controls to perform communication using the PCH communication control unit 401. Also, the communication control unit 403 controls to perform communication using the NPCH communication control unit 402 during a period when the PCH is occupied by the OBSS.

[0030] (Communication processing flow) Next, an example of the flow of communication processing executed in a wireless communication system will be described with reference to Fig. 5. In Fig. 5, it is assumed that, as in Fig. 1, AP101 is in a position where it can receive and decode a wireless frame from AP111, while STA102 is in a position where it cannot receive and decode the wireless frame. In Fig. 5, it is assumed that AP101 and STA102 use a first channel (CH1) as a PCH, and AP111 and STA112 can use CH1 as a PCH or NPCH.

[0031] In Fig. 5, it is assumed that AP101, STA102, AP111, and STA112 are not using CH1 (F501 to F504). Since PCH is not being used or occupied by OBSS, AP101 and STA102 do not use NPCH access and obtain access rights in PCH when they should transmit wireless frames. When AP101 and STA102 obtain access rights in PCH, they can use CH2, which is a second channel (CH2) that is NPCH, in a situation where that channel is not being used. In Fig. 5, it is shown that AP101 and STA102 are in a state where they can use CH2 in addition to CH1 at the time points F501 and F502.

[0032] In this state, for example, when data to be transmitted by occupying a channel occurs in the STA 112, the STA 112 transmits an occupancy request frame (F505). The occupancy request frame includes, for example, information specifying one or more channels to be occupied and information indicating the length of the period for occupying the channel. Note that the information indicating the length of the period for occupying the channel may be information for making surrounding APs and STAs set a NAV, similar to conventional Request To Send (RTS) frames and Clear To Send (CTS) frames. Also, the occupancy request frame may include a Duration field, similar to RTS frames and CTS frames, and the length of the period for occupying the channel may be indicated in the Duration field. Unless otherwise specified, the information indicating the length of the period for occupying the channel in the occupancy request frame in the following description may also be information for setting a NAV, and the period length may be indicated by the Duration field in the frame. By transmitting the occupancy request frame on that channel, information specifying the channel to be occupied may be implicitly notified, and the channel to be occupied may not be indicated as explicit information. For example, the occupancy request frame may be transmitted on all channels requesting occupancy, and in that case, information indicating the channel requesting occupancy may not be included in the frame. Also, when the occupancy request frame is configured to be always transmitted on some of the channels to be occupied, if there are multiple channels to be occupied, the channels other than the channel on which the frame is transmitted may be indicated as the channels to be occupied. For example, when requesting occupancy of the PCH of an OBSS, the occupancy request frame may be transmitted on the PCH of the OBSS, and information indicating information of channels other than the PCH for which occupancy is requested may be included in the frame. Also, information indicating a list of channels for which occupancy is requested, including the channel on which the occupancy request frame is transmitted, may be included in the frame.5, the STA 112 requests the occupation of CH1, and transmits an occupation request frame on CH1. The occupation request frame does not need to include information on CH1 as information on the channel to be occupied. The channel to be occupied may be indicated by a list of channel numbers or by other information such as a frequency bandwidth.

[0033] When the AP111 receives this occupancy request frame, it transmits the occupancy request frame to a communication device (here, the AP101) of the OBSS (here, the network 103) seen from the AP111 (F506). The occupancy request frame here may include the same information as the occupancy target channel and period indicated in the occupancy request frame transmitted by the STA112. Note that this is only an example, and the occupancy request frame of F505 and the occupancy request frame of F506 may include information on the occupancy target channel and period different from each other, such as increasing the occupancy target channel or period when there is data to be transmitted in the AP111. Furthermore, when there is data to be transmitted by occupying a channel, the AP111 may transmit the occupancy request frame spontaneously without receiving the occupancy request frame from the STA112. In this case, the occupancy request frame includes information specifying one or more channels to be occupied, determined according to the size of the data to be transmitted, and information indicating the length of the period to occupy the channel. The AP 111 may transmit an occupancy request frame only when requesting occupancy (use) of a PCH in the OBSS (network 103), or may transmit an occupancy request frame regardless of the channel for which occupancy is requested.

[0034] It should be noted that while AP111 is transmitting an occupancy request frame, CH1 is busy and AP101 is unable to use CH1 and CH2. On the other hand, if AP101 does not detect a signal from STA112 with sufficient power, it is able to use CH1 (and CH2) while an occupancy request frame from STA112 is being transmitted. Also, STA102 is able to use CH1 (and CH2) while AP111 and STA112 are transmitting occupancy request frames without detecting wireless frames from AP111 and STA112 with sufficient power.

[0035] When the AP101 receives an occupancy request frame from the AP111 of the OBSS, the AP101 judges whether or not to permit occupancy of the CH1 on which the frame was received or the channel specified in the frame. Then, the AP101 transmits an occupancy response frame including the judgment result (F507). For example, this occupancy response frame may be a frame indicating to the AP111 that occupancy of the channel specified by the occupancy request frame is permitted. Also, the occupancy response frame may be a frame instructing a STA (here, STA102) belonging to the network 103 constructed by the AP101 to execute NPCH access. That is, by receiving the occupancy response frame, the AP111 judges that occupancy of the channel is permitted, and the STA102 may interpret the same occupancy response frame as an instruction to use NPCH access. The occupancy response frame may include, for example, information indicating a channel for which occupancy is permitted and information indicating a period for which occupancy is permitted. Here, the information indicating a period for which occupancy of the channel is permitted may also be information indicating a period for which surrounding APs and STAs are to set NAV, similar to the conventional RTS frame and CTS frame. In addition, the occupancy response frame may include a Duration field like the RTS frame or CTS frame, and the Duration field may indicate the length of the period during which the channel is permitted to be occupied. Unless otherwise specified, the information indicating the length of the period for occupying the channel in the occupancy response frame in the following description may also be information for setting the NAV, and the period length may be indicated by the Duration field in the frame. This allows the AP111 to recognize that it can occupy the designated channel and perform communication within the designated period. In addition, the STA102 can recognize that it should perform NPCH access in an unoccupied channel within the designated period. The AP101 may transmit a frame indicating that the STA102 should use NPCH access to the STA102 separately from the occupancy response frame to the AP111.The occupancy response frame may be a multicast frame including a portion storing data for the AP 111 and a portion storing data for the connected STA (STA 102 in this case). When control is performed using separate wireless frames, detailed information can be provided individually to the STA 102 and the OBSS AP 111. On the other hand, when control is performed using one wireless frame, the number of wireless frames for control transmitted and received can be reduced, improving communication efficiency.

[0036] The information notified from the AP101 to the STA of the BSS (STA102 in this case) may include, for example, information indicating the SPCH. However, if the SPCH is determined in advance between the AP101 and the STA102 and the channel is not occupied, the information indicating the SPCH may not be included. In addition, the information may instruct the STA to prohibit transmission of wireless frames on any channel. For example, when the channels to be occupied by the OBSS include all channels available in the BSS103, the prohibition of transmission of wireless frames may be instructed. In addition, the information notified from the AP101 to the STA of the BSS (STA102 in this case) may include information indicating the period length during which NPCH access should be performed or the period length during which transmission of wireless frames is prohibited. By specifying this period length, it becomes unnecessary to transmit a notification for ending NPCH access or lifting the prohibition of transmission of wireless frames, so that it is possible to suppress a decrease in communication efficiency due to an increase in control communication. The period length specified here may be, for example, equal to the period length requested by the AP of the OBSS to occupy a channel in F506, but is not limited thereto. For example, the STA may be notified of the specified period length plus a period length during which an occupancy response frame is transmitted from the AP 111 to the STA 112 as described later and a certain period length such as SIFS (Short IFS). The period length during which occupancy is permitted notified to the AP of the OBSS and the period length during which NPCH access should be performed or transmission of wireless frames is prohibited notified to the STA in the BSS may be the same or different. For example, periods of different lengths may be set in consideration of propagation delay, processing time, etc.

[0037] When the STA102 receives this frame from the AP101, the STA102 performs control to transition to a state in which no wireless frame is transmitted on the PCH and NPCH access is performed to transmit wireless frames using the NPCH (F508, F509). After transitioning to this state, for example, if the SPCH is designated as CH2, the STA102 can confirm that CH2 is in an idle state and transmit data using one or more NPCHs including CH2. After that, when the period designated in the seclusion response frame of F507 has elapsed, the STA102 performs control to return to a state in which communication is performed using the PCH again (F510). Similarly, after transmitting the seclusion response frame (F507), the AP101 also performs control to transition to a state in which no wireless frame is transmitted on the PCH and NPCH access is performed to transmit wireless frames using the NPCH (F511, F512). Then, the AP 101 performs control so as to return to a state in which communication is performed using the PCH again after the period specified in the occupancy response frame of F507 has elapsed (F513).

[0038] On the other hand, when the occupancy response frame transmitted from the AP 101 in F507 indicates that occupancy of the CH1 is permitted, the AP 111 transmits an occupancy response frame indicating that occupancy of the CH1 is permitted to the STA 112 (F514). As a result, the CH1 is in an occupied state in the network 113, and the AP 111 and the STA 112 use the CH1 to perform data communication during the period in which the CH1 is occupied (F515, F516). After that, the AP 111 and the STA 112 transition to a state in which the CH1 is not occupied as the occupancy period of the CH1 elapses. In this state, the CH1 is not occupied, but a wireless frame can be transmitted when the CH1 is in an idle state (F517, F518). As an example, an RTS frame may be used as the occupancy request frame transmitted from the STA 112 to the AP 111 in F505. For example, the STA 112 transmits an RTS frame on all channels for which occupancy is requested. Then, AP111 may specify the channel on which the RTS frame was received from STA112, include information indicating the specified channel as information indicating the channel for which occupancy is requested in an occupancy request frame, and transmit the frame to AP101. Then, in response to permission for occupancy of the channel, AP111 transmits a CTS frame on each of the channels for which occupancy is permitted. This allows STA112 to adjust the channels to be used between BSSs while maintaining the conventional configuration. Note that the RTS frame may include a list of channels for which occupancy is requested, and the CTS frame may include a list of channels for which occupancy is permitted, so that these frames are transmitted and received on one channel.

[0039] (Processing flow executed by AP) Next, the operation of the APs (AP101 and AP111) will be described with reference to Figs. 6 to 9. This process may be implemented, for example, in a form in which the control unit 302 executes a program stored in the storage unit 301, or may be implemented as a processing function in the communication unit 306. The AP may start this process in response to the wireless LAN function being enabled by turning on the power, etc. The AP first sets an operating channel (PCH and one or more NPCHs) (S601). This setting may be performed, for example, by a user input, or may be performed automatically in response to information such as the congestion status of multiple channels that the AP can use. After this, in the network established by the AP, communication is performed in the set PCH and one or more NPCHs.

[0040] The AP waits to receive a wireless frame on one or more channels including the PCH (S602). Here, if the AP does not use NPCH access, when the AP receives a signal from a STA in its own BSS, the AP always receives a wireless frame using a channel including the PCH. On the other hand, in the OBSS, a channel different from the PCH set in S601 can be used as the PCH. Therefore, the wireless frame that the AP receives on a channel not including the PCH is a wireless frame from the OBSS. At this time, if an occupancy request frame is transmitted in parallel on all channels for which occupancy is requested, and if the frame is received on a channel not including the PCH, even if the channel is occupied, it will be a channel other than the PCH. In other words, if an occupancy request frame is transmitted on all channels to be occupied, the AP can determine that the wireless frame received on a channel not including the PCH is not a frame addressed to the AP and that the PCH will not be occupied. Therefore, when the AP receives a wireless frame on a channel not including the PCH (NO in S602), the AP does not perform any process related to reception and moves the process to S608. In addition, when an occupancy request frame requesting occupancy of a plurality of channels is transmitted on one channel, the AP may decode the frame, taking into consideration a case where occupancy of the PCH is requested on a channel other than the PCH. Then, when the AP determines that occupancy of the PCH is not requested in the frame, the AP may operate to move the process to S608. In addition, for example, even if the PCH in the own BSS (network 113) is CH2, when the PCH of the OBSS (network 103) is CH1 and occupancy of CH1 is requested, the AP 111 may transmit the occupancy request frame on CH1. That is, the occupancy request frame may be transmitted on the PCH in the network that receives the occupancy request. In this case, when occupancy of the PCH is requested, the AP 101 always receives the occupancy request frame on the PCH.Therefore, during periods when the AP is not accessing the NPCH, the AP can ignore radio frames received on channels that do not include a PCH, since these frames do not request occupancy of the PCH.

[0041] When the AP receives a wireless frame on one or more channels including the PCH (YES in S602), it judges whether the frame is an occupancy request frame from a STA of its own BSS (S603). When the AP receives an occupancy request frame from a STA of its own BSS (YES in S603), it moves the process to S604. This process of S604 is, for example, the process when the AP 111 receives an occupancy request frame at F505 in FIG. 5. The details of this process will be described later. When the received frame is not an occupancy request frame from a STA of its own BSS (NO in S603), it judges whether the frame is an occupancy request frame from an AP of the OBSS (S604). When the AP receives an occupancy request frame from an AP of the OBSS (YES in S604), it moves the process to S606. This process of S606 is, for example, the process when the AP 101 receives an occupancy request frame from the AP 111 at F506 in FIG. The details of this process will be described later. If the received frame is not an occupancy request frame from an AP of the OBSS (NO in S604), the AP executes processing according to the frame (S607). This processing is processing for frames related to conventional communications, such as normal data and control frames, and is not related to this embodiment, so it will not be described in detail.

[0042] Here, the process of S604 will be described with reference to FIG. 7. When the AP receives an occupancy request frame from a STA of its own BSS (YES in S603), it judges whether or not to permit occupancy of the channel (S701). For example, the AP may judge whether or not to occupy the channel based on the congestion state of its own BSS and characteristics such as the allowable delay and throughput of the traffic to be transmitted. When the AP judges not to permit occupancy of the channel (NO in S701), it transmits an occupancy response frame indicating a denial of channel occupancy to the STA that transmitted the occupancy request frame (S709) and ends the process. Note that when the AP judges not to permit occupancy of the channel, it does not have to respond at all. In this case, when the STA does not receive a response within a predetermined period, it may judge that occupancy has not been permitted. On the other hand, when the AP judges to permit occupancy of the channel (YES in S701), it judges whether the channel requested for occupancy includes the PCH of the OBSS (S702). When the PCH of the OBSS is included in the channels for which occupancy is requested (YES in S702), the AP transmits an occupancy request frame to the AP of the OBSS (S703). The AP may transmit the occupancy request frame on all channels for which occupancy is requested, or may transmit the occupancy request frame only on the PCH of the OBSS. In one example, the AP may identify the PCH of the OBSS by decoding a wireless frame (e.g., a Beacon frame) from the AP of the OBSS. The AP may also obtain information on the PCH of the OBSS by communicating in advance (wired or wireless) with the AP of the OBSS. Note that, when the AP of the OBSS is configured to decode wireless frames of channels other than the PCH of the OBSS, the AP may transmit the occupancy request frame on at least one of the channels available in the OBSS.

[0043] After transmitting the channel occupancy request, the AP waits to receive an occupancy response frame from the AP of the OBSS (S704). If the AP receives an occupancy response frame indicating a denial of channel occupancy, or if the AP does not receive a channel occupancy response frame within a predetermined period (NO in S704), the AP determines that channel occupancy is not permitted. The AP then transmits an occupancy response frame indicating a denial of channel occupancy to the STA that transmitted the occupancy request frame received in S603 (S709) and ends the process. On the other hand, if the AP receives an occupancy response frame indicating a permission of channel occupancy (YES in S704), the AP transmits an occupancy response frame indicating a permission of channel occupancy to the STA that transmitted the occupancy request frame received in S603 (S705). The AP then waits to receive a frame from the STA using the channel that is permitted to be occupied (S706), and if the AP receives a frame (YES in S706), it executes a process according to the frame (S707). The AP continues frame reception processing (S706, S707) until the channel occupancy period expires (NO in S708), and ends the processing when the occupancy period expires (YES in S708). After the processing in FIG. 7 ends, the processing proceeds to S608 in FIG. 6.

[0044] Next, the process of S606 will be described with reference to FIG. 8. When an AP receives an occupancy request frame from an AP of an OBSS (YES in S605), the AP judges whether or not to permit occupancy of the channel (S801). For example, the AP may judge whether or not to occupy the channel based on the congestion state of its own BSS and characteristics such as the allowable delay and throughput of the traffic to be transmitted. When the AP judges not to permit occupancy of the channel (NO in S801), it transmits an occupancy response frame indicating a denial of channel occupancy to the AP of the OBSS that is the source of the occupancy request frame (S810) and ends the process. In this case, the AP may transmit a notification to the STA of its own BSS indicating that NPCH access should not be used or that transmission of wireless frames is not prohibited, separate from the occupancy response frame, but may not transmit such a notification. That is, when the STA interprets the occupancy response frame as an instruction to use NPCH access or to prohibit transmission of wireless frames regardless of its contents, such a separate notification may be transmitted from the AP to the STA. On the other hand, when the STA checks the contents of the exclusive response frame and determines the control, such a notification does not have to be transmitted. Also, when it is determined that the NPCH access should be used or the transmission of the radio frame is prohibited, if the determination result is notified to the STA separately from the exclusive response frame, the STA may be notified that the NPCH access should be used without the notification.

[0045] When the AP determines that the occupancy of the channel is permitted (YES in S801), the AP determines whether the channel requested for occupancy includes all channels available in the own BSS (S802). That is, the AP determines whether there is a channel that can be used without being occupied. If there is a channel that is not requested for occupancy, the AP transmits a radio frame to the STA of the own BSS instructing the STA to transition to a state in which NPCH access should be performed (S803). The AP also transmits an occupancy response frame indicating that the occupancy of the channel is permitted to the AP of the OBSS that transmitted the occupancy request frame (S803). Note that the information instructing the STA of the own BSS to transition to a state in which NPCH access should be performed may be included in the occupancy response frame, but the information may be transmitted in a separate radio frame. Note that the information instructing the STA to transition to a state in which NPCH access should be performed includes information indicating an SPCH selected from among unoccupied channels. This information also includes information indicating the duration of the state in which NPCH access should be performed. This duration corresponds to the time that the BSS occupies the PCH of its own BSS, but may be set to a time longer or shorter than that occupancy time.

[0046] Thereafter, communication using NPCH access is performed until the channel occupation period of the OBSS expires (NO in S809). That is, the AP waits for a frame in the NPCH including the SPCH (S804). Then, when the AP receives a frame in the NPCH including the SPCH (YES in S804), it executes processing according to the received frame (S805) and proceeds to processing S806. When the AP does not receive a frame in the NPCH including the SPCH (NO in S804), it proceeds to processing S806 without performing processing S805. In S806, the AP determines whether a frame to be transmitted has occurred. Then, when a frame to be transmitted has occurred (YES in S806), the AP detects that the SPCH is in an idle state (YES in S807) and then transmits the frame to be transmitted in the NPCH including the SPCH (S808). On the other hand, if there is no frame to be transmitted (NO in S806) or the SPCH is not in an idle state (NO in S807), the process of S808 is not performed, and if the channel occupation period of the OBSS has not yet expired (NO in S809), the process returns to S804. Note that, although an example in which the transmission process is performed after the reception process is shown in Fig. 8, the order of these processes may be reversed. If the channel occupation period of the OBSS has then expired (YES in S809), the process of Fig. 8 ends.

[0047] Returning to S802, if there is no channel for which occupancy has not been requested (NO in S802), the AP transmits an occupancy response frame indicating permission to occupy the channel to the AP of the OBSS (S811). The AP also transmits information to the STAs of its own BSS instructing them to prohibit transmission of wireless frames (S811). Note that the information to instruct the STAs of its own BSS to prohibit transmission of wireless frames may be included in the occupancy response frame, but the information may also be transmitted in a separate wireless frame. Thereafter, the AP waits without communication until the channel occupancy period of the OBSS expires (S812), and ends the process in response to the expiration of the occupancy period (YES in S812). After the process of FIG. 8 ends, the process proceeds to S608 in FIG. 6.

[0048] Returning to FIG. 6, the AP judges whether a frame to be transmitted has occurred (apart from a frame to be transmitted that has occurred during processing due to a wireless frame transmitted from a STA of the own BSS or an AP of the OBSS) (S608). If such a frame to be transmitted does not exist (NO in S608), the AP returns the process to S602 and repeats the process of FIG. 6 unless the wireless LAN function is disabled (NO in S613). On the other hand, if a frame to be transmitted exists (YES in S608), the AP judges whether a channel should be occupied to transmit the frame (S609). The AP makes this judgment based on, for example, the allowable delay and the required throughput of the frame to be transmitted. In one example, the AP judges that channel occupation is necessary when the allowable delay is equal to or less than a predetermined time or the required throughput exceeds a predetermined value. If the AP judges that channel occupation is not necessary (NO in S609), it confirms that the PCH is in an idle state (YES in S611) and transmits the frame to be transmitted using an idle channel including the PCH (S612). On the other hand, if the AP cannot confirm that the PCH is in an idle state (NO in S611), it does not transmit the frame to be transmitted. Then, unless the wireless LAN function is disabled (NO in S613), the AP returns the process to S602 and repeats the process in Fig. 6. If the AP determines that the channel needs to be occupied (YES in S609), it subsequently executes the process of S610.

[0049] Here, the process of S610 will be described with reference to FIG. 9. This process corresponds to the process in FIG. 5, in which the AP 111 determines that a transmission target frame has occurred in its own device and transmits an occupancy request frame F506 without receiving an occupancy request frame F505 from the STA 112. The AP transmits an occupancy request frame to the AP of the OBSS in order to occupy the channel (S901). In addition, when the AP does not request occupancy of the PCH of the OBSS, it may occupy the channel using the RTS / CTS mechanism instead of transmitting an occupancy request frame. After transmitting the occupancy request frame, the AP determines whether or not it has received an occupancy response frame indicating permission for occupancy of the channel from the AP of the OBSS (S902). When the AP receives an occupancy response frame indicating denial of occupancy of the channel, or when it has not received an occupancy response frame within a predetermined period (NO in S902), it determines that the channel cannot be occupied, and ends the process without transmitting a wireless frame. On the other hand, when the AP receives an occupancy response frame indicating permission to occupy the channel from the AP of the OBSS (YES in S902), the AP transmits an occupancy response frame indicating permission to occupy the channel to the STA of its own BSS (S903). Note that the occupancy response frame of S903 may be a frame in a format other than the occupancy response frame, as long as it is information indicating that the channel is occupied for the AP to transmit a wireless frame and that the STA is prohibited from transmitting a wireless frame during the occupancy period. After transmitting the occupancy response frame, the AP transmits the wireless frame to be transmitted on the channel that has been permitted to be occupied until the channel occupancy period expires (while NO in S905) (S904). After the channel occupancy period expires (YES in S905), the AP returns the process to S613 in FIG. 6.

[0050] (Processing flow performed by STA) Next, the operation of the STA (STA102 and STA112) will be described with reference to FIG. 10 to FIG. 13. This process may be implemented, for example, in a form in which the control unit 302 executes a program stored in the storage unit 301, or may be implemented as a processing function in the communication unit 306. The STA may start this process in response to the activation of the wireless LAN function by turning on the power or the like. The STA first sets an operating channel (PCH and one or more NPCHs) (S1001). This setting may be determined, for example, based on the result of searching for an AP. This setting may also be performed by user input. In one example, the STA may search for an AP, and a user operation may be selected to connect to one of the APs found by the search, and the STA may decide to use the operating channel set by the AP. The operating channel designated by the user selection accepted in the STA may also be notified to the AP, and the AP may be set to use the operating channel. After this, the STA will communicate in the network in which it is participating, in the set PCH and one or more NPCHs.

[0051] The STA waits to receive a wireless frame on one or more channels including the PCH (S1002). If the STA does not receive a wireless frame on the channel including the PCH (NO in S1002), the STA advances the process to S1010. The STA may also advance the process to S1010 if it receives a wireless frame from an AP of the OBSS or a STA on a channel including the PCH. On the other hand, if the STA receives a wireless frame (from the AP of the own BSS) on a channel including the PCH (YES in S1002), the STA switches the process to be performed depending on the type of the frame. That is, if the STA determines that the received frame is an occupancy response frame indicating permission for channel occupancy from the AP of the own BSS (YES in S1003), the STA executes the process of S1004. The process of S1004 will be described later. On the other hand, if the STA determines that the received frame is an occupancy response frame instructing a transition to a state in which NPCH access should be performed from the AP of the own BSS (NO in S1003, YES in S1005), the STA executes the process of S1006. The process of S1006 will also be described later. If the STA determines that the received frame is an occupancy response frame indicating prohibition of transmission from the AP of its own BSS (NO in S1003, NO in S1005, YES in S1007), it waits until the channel occupancy period of the OBSS expires (S1008). Then, when the channel occupancy period of the OBSS expires (YES in S1008), the STA moves the process to S1010. If the STA determines that the received frame is another frame (NO in S1003, NO in S1005, NO in S1007), it executes a process according to that frame (S1009) and moves the process to S1010. This process is a process for frames related to conventional communication such as normal data and control frames, and is not related to this embodiment, so it will not be described in detail.

[0052] Here, the process of S1004 will be described with reference to FIG. 11. This process corresponds to the process when the STA112 in FIG. 5 receives an occupancy response frame of F514 in a state where it has not transmitted an occupancy request frame of F505. That is, the process of FIG. 11 is the process when a frame to be transmitted exists in the AP of the own BSS, and the occupancy of the channel is permitted for the AP to transmit the frame. When the STA receives an occupancy response frame indicating permission for channel occupancy from the AP of the own BSS (YES in S1003), the STA waits for the frame from the AP of the own BSS to arrive in the occupied channel (S1101). When the STA receives the frame (YES in S1101), the STA executes a process according to the received frame (S1102). The STA repeats the processes of S1101 and S1102 until the occupancy period of the channel expires (S1103). Note that the STA, instead of the AP, may transmit an acknowledgment (ACK), data, or the like during the occupancy period of the channel. When the channel occupation period expires (YES in S1103), the STA ends the process in FIG. 11 and proceeds to S1010 in FIG.

[0053] Next, the process of S1006 will be described with reference to FIG. 12. This process corresponds to the process when STA102 in FIG. 5 receives an occupancy response frame of F507. The STA waits for a frame to arrive in one or more NPCHs including the SPCH (S1201). Then, when the STA receives a frame (YES in S1201), it executes a process according to the frame (S1202). The STA also determines whether a frame to be transmitted exists (S1203). Then, if a frame to be transmitted exists (YES in S1203), the STA confirms that the SPCH is in an idle state (YES in S1204), and transmits the frame in one or more NPCHs including the SPCH (S1205). Note that, although FIG. 12 shows an example in which a transmission process is performed after a reception process, this order may be reversed. That is, the STA may perform the processes in any order as long as it performs the reception processes of S1201 and S1202 when a frame is received, and performs the transmission processes of S1203 to S1205 when a frame to be transmitted exists. The STA repeats the above-mentioned reception and transmission processes until the channel occupation period of the OBSS indicated in the occupancy response frame expires (while NO is returned in S1206). Then, when the channel occupation period of the OBSS expires (YES is returned in S1206), the STA ends the process of FIG. 12 and proceeds to S1010 in FIG. 10.

[0054] Returning to FIG. 10, in S1010, the STA judges whether there is a frame to be transmitted. If there is no such frame to be transmitted (NO in S1010), the STA returns the process to S1002 and repeats the process of FIG. 10 unless the wireless LAN function is disabled (NO in S1015). On the other hand, if there is a frame to be transmitted (YES in S1010), the STA judges whether the channel should be occupied to transmit the frame (S1011). The STA makes this judgment based on, for example, the allowable delay and the required throughput of the frame to be transmitted. For example, the STA judges that the channel occupation is necessary when the allowable delay is equal to or less than a predetermined time or the required throughput exceeds a predetermined value. If the STA judges that the channel occupation is not necessary (NO in S1011), it confirms that the PCH is in an idle state (YES in S1013) and transmits the frame to be transmitted using an idle channel including the PCH (S1014). On the other hand, if the STA cannot confirm that the PCH is in the idle state (NO in S1013), it does not transmit the frame to be transmitted. Then, unless the wireless LAN function is disabled (NO in S1015), the STA returns to the process of S1002 and repeats the process of Fig. 10. If the STA determines that the channel needs to be occupied (YES in S1011), it subsequently executes the process of S1012.

[0055] Here, the process of S1012 will be described with reference to FIG. 13. This process corresponds to the process in FIG. 5, in which the STA 112 judges that a frame to be transmitted has occurred in the own device and transmits an occupancy request frame of F505. When a frame to be transmitted that requires channel occupancy occurs, the STA transmits an occupancy request frame to the AP of the own BSS (S1301). Then, when the STA receives an occupancy response frame indicating permission to occupy the channel from the AP of the own BSS (YES in S1302), the STA transmits a wireless frame using the occupied channel (S1303). This wireless frame is transmitted during the occupancy period indicated by the occupancy response frame (NO in S1304). Note that the AP may transmit data or an ACK during this occupancy period. After the occupancy period expires (YES in S1304), the STA returns the process to S1015 in FIG. 10.

[0056] In this manner, in this embodiment, a frame regarding a request for channel occupancy and permission or denial of the request is transmitted and received between APs each constructing a separate BSS, and each AP transfers the contents of the frame to its subordinate STA. This allows APs and STAs belonging to multiple BSSs to recognize whether the PCH is occupied due to communication by another BSS. As a result, it is possible to share the recognition of whether the PCH can be used in each BSS and whether NPCH access should be used, and it becomes possible to communicate efficiently. In addition, negotiations regarding channel occupancy are performed between BSSs, so that it becomes possible to appropriately adjust the channel occupancy according to the situation in each BSS.

[0057] In the above embodiment, an example in which permission or denial of channel occupancy is indicated has been described. However, when occupancy of a plurality of channels is requested, some of the channels may be permitted and the remaining few may be denied. For example, when an occupancy request frame is transmitted on each of a plurality of channels for which occupancy is requested, an occupancy response frame indicating that occupancy is permitted or denied on each of the channels may be transmitted, thereby permitting occupancy of only some of the channels. When an occupancy request frame is transmitted on only some of the channels for which occupancy is requested (for example, the PCH of the OBSS), information indicating at least one of the channels for which occupancy is permitted and the channels for which occupancy is denied may be included in the occupancy response frame and transmitted. In addition, information indicating the minimum number of channels (or bandwidth) required may be indicated in the occupancy request frame. In this case, when the occupancy of the minimum number of channels (or bandwidth) is not permitted, occupancy may be denied on all channels. In addition, when occupancy of a channel is denied, the AP and the STA may operate not to communicate on that channel, or may execute contention-based channel access on that channel. That is, if the AP and STA are denied occupancy of a channel, they may not occupy the channel, but may access the channel by conventional Carrier Sense Multiple Access (CSMA) to perform communication.

[0058] (Modification) In the above embodiment, an example has been described in which an AP requests occupancy of a channel, and when occupancy of the channel is permitted by an AP of the OBSS, the AP can occupy the channel, but the present invention is not limited to this. For example, an AP may "declare" occupancy of a channel by an occupancy request frame, and may occupy the channel and perform communication without a response from the AP of the OBSS. An example of the flow of communication in this case is shown in FIG. 14. Note that the term "occupancy request frame" is used in the following description, but it may be read as "occupancy declaration frame". For example, when the AP 111 receives an occupancy request frame from the STA 112 (F505), the AP 111 transmits an occupancy response frame (F1401). Also, the AP 111 transmits an occupancy request frame based on the occurrence of a frame to be transmitted in the own device (F1401). Hereinafter, the occupancy request frame and the occupancy response frame may be collectively referred to as an "occupancy request / response frame". The occupancy request / response frame is received not only by the AP 101 of the OBSS, but also by the STA 112 of the own BSS. This occupancy request / response frame is a frame that declares that the designated channel will be occupied after a predetermined time has elapsed since its transmission. This predetermined time may correspond to, for example, a time to wait for a frame for occupying a channel in a BSS to be transmitted and received in an OBSS. That is, it may be a time to wait for the AP 101 to instruct the STA 102 to use NPCH access or to prohibit frame transmission. The predetermined time may be, for example, a time length obtained by adding a predetermined IFS to the length of a wireless frame in which the AP 101 transmits an instruction to the STA 102. After a predetermined time has elapsed since the transmission or reception of the occupancy request / response frame, the AP 111 and the STA 112 perform data communication using the channel for which occupancy has been declared (F1403, F1404). Note that, when the AP 101 receives this occupancy request / response frame, it may not respond, but may transmit an occupancy response frame as in the case of FIG. 5 (F1402). The occupancy response frame here may be transmitted to the STA 102 to instruct the STA 102 to use NPCH access or to prohibit transmission. Since it is sufficient for the AP 101 to be able to issue this instruction, the AP 101 may transmit this instruction in a format other than a "response."On the other hand, when the AP 111 and the STA 112 receive this occupancy response frame, they can occupy the channel and perform communication immediately after receiving the frame.

[0059] An example of the flow of processing by the AP in this case will be described with reference to Figures 15 to 18. In Figures 15 to 18, the same processes as those in Figures 6 to 9 are denoted with the same reference numerals, and detailed description will be omitted. The processing in Figure 15 differs from the processing in Figure 6 in the processing when an exclusive use request frame is received from a STA in the own BSS (S1501), the processing when an exclusive use request / response frame is received from an AP in the OBSS (S1503), and the processing for channel occupancy (S1504). There is also a formal difference (S1502) due to the fact that not only an exclusive use request frame but also an exclusive use response frame is received from the AP in the OBSS.

[0060] FIG. 16 shows the flow of the process of S1501. When an AP receives an occupancy request frame requesting occupancy of the PCH of the OBSS from a STA of its own BSS (YES in S702), the AP transmits an occupancy response frame to the STA of its own BSS and the AP of the OBSS (S1601). This occupancy response frame contains the same information as the occupancy request frame transmitted by the AP 111 in the above example, except that it is a declaration of occupancy of the channel, not a request for occupancy of the channel. That is, information indicating the channel to be occupied and information indicating the period of occupancy are included in the occupancy response frame. Note that a frame in the form of an occupancy request frame may be transmitted instead of the occupancy response frame. After that, when the AP receives a response frame from the AP of the OBSS or when a predetermined time has passed (YES in S1602), the AP recognizes that the channel is occupied, and performs a process of receiving a wireless frame from the STA of its own BSS using that channel. Other processes are the same as those in FIG. 7.

[0061] Fig. 17 shows the flow of the process of S1503. In this modification, when an AP receives an occupancy request frame from an AP of an OBSS, the AP does not reject the frame. Therefore, the processes of S801 and S810 are omitted from the process of Fig. 8. The other processes are the same as those of Fig. 8.

[0062] FIG. 18 shows the flow of the process of S1504. When the AP transmits data generated in the own device in a state where the PCH is available, the AP transmits an exclusive use request frame not only to the AP of the OBSS but also to the STA of the own BSS (S1801). Note that the AP may transmit an exclusive use response frame when transmitting data generated in the own device in S1801, for example, when the AP receives an exclusive use request frame due to the occurrence of data to be transmitted in the STA of the own BSS. Then, in response to the passage of a predetermined time after the transmission of the exclusive use request frame (YES in S1802), the AP executes a process of transmitting a wireless frame on the channel for which the exclusive use has been declared. Also, when the AP receives an exclusive use response frame from the AP of the OBSS, the AP may execute a process of transmitting a wireless frame even before the passage of the predetermined time. Note that in this modification, the AP may transmit a wireless frame assuming that the channel is occupied, regardless of the content of the exclusive use response frame. Other processes are the same as those in FIG. 9.

[0063] Next, an example of the process flow of the STA will be described with reference to Figs. 19 to 21. The process of Fig. 19 is the same as the process of Fig. 10, except for the process when a wireless frame requiring channel occupancy is transmitted in the AP (S1902) and the process when transmission target data requiring channel occupancy occurs in the STA (S1903). Note that there is also a formal difference (S1901) due to the fact that an occupancy request frame is received instead of an occupancy response frame when transmission target data exists in the AP of the BSS. Fig. 20 shows an example of the process flow of S1902. When the STA receives an occupancy request frame for transmitting a wireless frame requiring channel occupancy in the AP (YES in S1901), the STA waits for a predetermined time from the reception of the occupancy request frame (S2001). After the predetermined time has elapsed (YES in S2001), the STA executes a wireless frame reception process in the same manner as in Fig. 11. Note that, when the STA receives an occupancy response frame from the AP of the OBSS, it may execute the wireless frame reception process in the same manner as in FIG. 11 even before the predetermined time has elapsed. FIG. 21 shows an example of the process flow of S1903. When transmission target data that requires channel occupancy occurs, the STA transmits an occupancy request frame to the AP of its own BSS (S1301) and waits for the occupancy response frame (S2101). When the STA does not receive the occupancy response frame (NO in S2101), it determines that it cannot occupy the channel and ends the process without transmitting the transmission target frame (returning to the process in FIG. 19 and repeating the series of processes). On the other hand, when the STA receives an occupancy response frame from the AP of the own BSS (YES in S2101), it waits for the reception of the occupancy response frame from the AP of the OBSS or for the predetermined time to elapse (S2102). Then, upon receiving an occupancy response frame from the AP of the OBSS or upon the passage of a predetermined time (YES in S2102), the STA executes a process of transmitting the frame to be transmitted using the channel declared as occupied by the AP.

[0064] In this way, when a frame declaring occupancy is used, for example, after an occupancy request frame is transmitted from an AP, it is not necessary to receive permission from the AP of the OBSS and then notify the STA of the permission. This makes it possible to reduce the time during which data cannot be transmitted or received between the AP and the STA, and to perform communication using frequency resources more efficiently.

[0065] The above-mentioned occupancy request frame and occupancy response frame are terms used to explain the nature of the frame, and the names of the frames may be changed as a matter of course. In addition, in the above-mentioned embodiment, an example in which the roles of the AP and the STA are clearly distinguished is described, but the distinction between these devices does not necessarily have to be made. That is, the process described as being performed by the AP may be performed by the STA, and the process described as being performed by the STA may be performed by the AP. In addition, the above-mentioned embodiments may be used in any combination, and some processes may not be performed as long as they do not deviate from the spirit of the invention.

[0066] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0067] (Summary of the embodiment) At least some of the above-described embodiments can be summarized as follows. (Item 1) A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for establishing a first network and communicating with a first other communication device belonging to the first network by using either a first communication method using at least a first channel used for acquiring a transmission right and one or more second channels different from the first channel, or a second communication method using one or more of the second channels without using the first channel; the communication means receives a wireless frame related to the occupancy of one or more channels including the first channel from a second other communication device constructing a second network different from the first network, and when one or more channels including the first channel are occupied in the second network, transmits a notification to the first other communication device instructing the use of the second communication method or prohibiting transmission of wireless frames; A communication device comprising: (Item 2) the radio frame related to the occupancy of one or more channels including the first channel is a radio frame requesting the occupancy of one or more channels including the first channel; the communication device further comprises a determination means for determining whether or not to permit occupancy of one or more channels including the first channel when a wireless frame requesting occupancy of one or more channels including the first channel is received; when the communication means permits occupancy of one or more channels including the first channel, the communication means transmits a response indicating that the request is permitted to the second other communication device, and transmits a notification instructing the first other communication device to use the second communication method or to prohibit transmission of wireless frames; 2. The communication device according to item 1, (Item 3) 3. The communication device according to item 2, wherein the notification is included in the response. (Item 4) 4. The communication device according to claim 2 or 3, wherein the response includes information indicating a period during which occupation of one or more channels including the first channel is permitted. (Item 5) The communication device described in any one of items 2 to 4, characterized in that when the communication means does not allow occupancy of one or more channels including the first channel, it transmits a response to the second other communication device indicating that the request is rejected, and does not transmit the notification to the first other communication device. (Item 6) The communication device described in item 1, characterized in that the radio frame regarding the occupancy of one or more channels including the first channel is a radio frame that declares the occupancy of one or more channels including the first channel, and when the radio frame is transmitted from the second other communication device, one or more channels including the first channel are occupied in the second network. (Item 7) The communication device described in any one of items 1 to 6, characterized in that the communication means transmits the notification to the first other communication device instructing it to prohibit transmission of wireless frames when all of the channels available for communication between the communication device and the first other communication device are occupied by the second other communication device. (Item 8) 8. The communication device according to claim 1, wherein the notification includes information indicating a period during which the second communication method should be used or a period during which transmission of the wireless frame is prohibited. (Item 9) The communication device described in any one of items 1 to 8, characterized in that the notification includes information specifying a channel among the second channels to be used to acquire a transmission right in the second communication method when instructing the first other communication device to use the second communication method. (Item 10) A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for communicating with a first other communication device by using either a first communication method using at least a first channel or a second communication method using one or more of the second channels without using the first channel, in one communication link consisting of a first channel used to participate in a first network established by a first other communication device and obtain a transmission right, and one or more second channels different from the first channel; the communication means uses the second communication method when it receives information instructing to use the second communication method in a response transmitted by the first other communication device in response to a wireless frame regarding the occupancy of one or more channels including the first channel transmitted by a second other communication device constructing a second network different from the first network, and does not transmit the wireless frame when it receives information instructing to prohibit transmission of the wireless frame in the response; A communication device comprising: (Item 11) 11. The communication device according to item 10, wherein the response includes information indicating a period during which the second communication method should be used or a period during which transmission of the wireless frame is prohibited. (Item 12) A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for establishing a first network and communicating with a first other communication device participating in the first network; the communication means is a second network in which communication is performed using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel, in one communication link composed of a first channel used to acquire a transmission right and one or more second channels different from the first channel, and transmits a wireless frame regarding the occupancy of one or more channels including the first channel to a second other communication device constructing the second network different from the first network; the communication means communicates with the first other communication device using one or more channels including the first channel based on the transmission of the wireless frame; A communication device characterized in that the wireless frame is a wireless frame that, when the second other communication device receives the wireless frame and one or more channels including the first channel are occupied in the first network, causes the second other communication device to send an instruction to a third other communication device participating in the second network to use the second communication method or to prohibit the transmission of the wireless frame. (Item 13) the radio frame related to the occupancy of one or more channels including the first channel is a radio frame requesting the occupancy of one or more channels including the first channel; The communication device described in item 12, characterized in that when the communication means receives a response from the second other communication device indicating permission for occupancy of one or more channels including the first channel, it communicates with the first other communication device using one or more channels including the first channel. (Item 14) Item 14. The communication device according to item 13, wherein the response includes information indicating a period during which occupation of one or more channels including the first channel is permitted. (Item 15) The communication device described in item 13 or 14, characterized in that when the communication means receives a response from the second other communication device indicating that occupancy of one or more channels including the first channel is permitted, it transmits information indicating that occupancy of one or more channels including the first channel is permitted to the first other communication device. (Item 16) The communication device described in any one of items 13 to 15, characterized in that when the communication means receives a response from the second other communication device indicating that occupancy of one or more channels including the first channel is not permitted, the communication means does not communicate with the first other communication device using one or more channels including the first channel. (Item 17) The communication device described in any one of items 13 to 15, characterized in that when the communication means receives a response from the second other communication device indicating that occupancy of one or more channels including the first channel is not permitted, it performs contention-based channel access with the first other communication device on one or more channels including the first channel. (Item 18) The radio frame regarding the occupancy of one or more channels including the first channel is a radio frame that declares the occupancy of one or more channels including the first channel; The communication device according to item 12, characterized in that the communication means communicates with the first other communication device using one or more channels including the first channel after a predetermined time has elapsed even if no response is received from the second other communication device. (Item 19) Item 19. The communication device according to item 18, characterized in that a radio frame declaring occupation of one or more channels including the first channel is also transmitted to the first other communication device. (Item 20) The communication device described in item 18 or 19, characterized in that the specified time is determined based on a period during which the second other communication device transmits an instruction to the third other communication device to use the second communication method or to prohibit transmission of wireless frames, and a specified Interframe Space (IFS). (Item 21) The communication device described in any one of items 12 to 20, characterized in that when the communication means receives a request from the second other communication device, it transmits a radio frame regarding the occupancy of one or more channels including the first channel to the first other communication device. (Item 22) A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for participating in a first network established by a first other communication device and communicating with the first other communication device; The communication means includes: transmitting a request to the first other communication device for occupancy of one or more channels including the first channel; A second network in which communication is performed using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel in one communication link composed of the first channel for acquiring a transmission right and one or more second channels different from the first channel, and when one or more channels including the first channel are occupied by the first other communication device transmitting a wireless frame regarding the occupancy of one or more channels including the first channel to a second other communication device constructing a second network different from the first network, communication is performed with the first other communication device using one or more channels including the first channel. A communication device comprising: (Item 23) The communication device described in item 22, characterized in that when the communication means receives a notification from the first other communication device that the first other communication device is permitted to occupy one or more channels including the first channel, it communicates with the first other communication device using one or more channels including the first channel. (Item 24) a radio frame regarding occupancy of one or more channels including the first channel, which is transmitted from the first other communication device to the second other communication device, is a radio frame declaring occupancy of one or more channels including the first channel; 23. The communication device according to item 22, characterized in that the communication means communicates with the first other communication device using one or more channels including the first channel after a predetermined time has elapsed since the wireless frame was transmitted. (Item 25) The communication device described in item 24, characterized in that the specified time is determined based on a period during which the second other communication device transmits an instruction to a third other communication device joining the second network to use the second communication method or to prohibit transmission of wireless frames, and a specified Interframe Space (IFS). (Item 26) A communication method is executed by a communication device that establishes a first network and performs communication in accordance with the IEEE 802.11 standard series with a first other communication device belonging to the first network, using either a first communication method that uses at least the first channel or a second communication method that does not use the first channel but uses one or more of the second channels in one communication link that is composed of a first channel used to establish the first network and acquire a transmission right and one or more second channels different from the first channel, the method comprising: receiving a wireless frame related to the occupancy of one or more channels including the first channel from a second other communication device constructing a second network different from the first network, and when one or more channels including the first channel are occupied in the second network, transmitting a notification to the first other communication device instructing the use of the second communication method or prohibiting transmission of wireless frames; A control method comprising: (Item 27) A communication method is executed by a communication device that performs communication in accordance with the IEEE 802.11 standard series with a first other communication device, using either a first communication method that uses at least a first channel, the first channel being used to participate in a first network established by the first other communication device and obtain a transmission right, and one or more second channels different from the first channel, in one communication link, the first communication method using the first channel, or a second communication method that does not use the first channel but uses one or more of the second channels, the method comprising: using the second communication method when receiving information instructing to use the second communication method in a response transmitted by the first other communication device to a wireless frame regarding the occupancy of one or more channels including the first channel transmitted by a second other communication device constructing a second network different from the first network; not transmitting the wireless frame when receiving information instructing to prohibit the transmission of the wireless frame in the response; A communication method comprising: (Item 28) A communication method executed by a communication device that establishes a first network and communicates with a first other communication device participating in the first network in accordance with the IEEE 802.11 standard series, comprising: a second network in which communication is performed using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel in one communication link composed of a first channel used to acquire a transmission right and one or more second channels different from the first channel, the second network transmitting a wireless frame regarding the occupancy of one or more channels including the first channel to a second other communication device constructing the second network different from the first network; performing communication with the first other communication device using one or more channels including the first channel based on the transmission of the wireless frame; Including, a communication method characterized in that the wireless frame, when received by the second other communication device and when one or more channels including the first channel are occupied in the first network, causes the second other communication device to transmit an instruction to a third other communication device participating in the second network to use the second communication method or to prohibit transmission of the wireless frame. (Item 29) A communication method executed by a communication device that participates in a first network established by a first other communication device and communicates with the first other communication device in accordance with the IEEE 802.11 standard series, comprising: transmitting a request to the first other communication device for occupancy of one or more channels including the first channel; a second network in which communication is performed using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel, in one communication link composed of the first channel for acquiring a transmission right and one or more second channels different from the first channel, and when one or more channels including the first channel are occupied by the first other communication device transmitting a wireless frame regarding the occupancy of one or more channels including the first channel to a second other communication device constructing a second network different from the first network, communication is performed with the first other communication device using one or more channels including the first channel; A communication method comprising: (Item 30) A program for causing a computer to function as each of the means possessed by the communication device according to any one of items 1 to 25.

[0068] The invention is not limited to the above-described embodiments, and various modifications and variations are possible 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]

[0069] 101: AP, 102: STA, 103: network, 111: AP, 112: STA, 113: network, 401: PCH communication control unit, 402: NPCH communication control unit, 403: communication control unit

Claims

1. A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for establishing a first network and communicating with a first other communication device belonging to the first network by using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel in one communication link consisting of a first channel used for acquiring a transmission right and one or more second channels different from the first channel; the communication means receives a wireless frame related to the occupancy of one or more channels including the first channel from a second other communication device constructing a second network different from the first network, and when one or more channels including the first channel are occupied in the second network, transmits a notification to the first other communication device instructing the use of the second communication method or instructing prohibition of transmission of wireless frames; A communication device comprising:

2. a radio frame related to occupancy of one or more channels including the first channel is a radio frame requesting occupancy of one or more channels including the first channel; the communication device further comprises a determination means for determining, when a wireless frame requesting occupancy of one or more channels including the first channel is received, whether or not to permit occupancy of the one or more channels including the first channel; the communication means transmits a response indicating that the request is permitted to be permitted to occupy one or more channels including the first channel to the second other communication device, and transmits a notification instructing the first other communication device to use the second communication method or to prohibit transmission of wireless frames; 2. The communication device according to claim 1 .

3. The communication device according to claim 2 , wherein the notification is included in the response.

4. The communication device according to claim 2 , wherein the response includes information indicating a period during which occupancy of one or more channels including the first channel is permitted.

5. The communication device according to claim 2, characterized in that, when the communication means does not allow occupancy of one or more channels including the first channel, it sends a response to the second other communication device indicating that the request is rejected, and does not send the notification to the first other communication device.

6. The communication device according to claim 1, characterized in that a radio frame regarding occupancy of one or more channels including the first channel is a radio frame that declares occupancy of one or more channels including the first channel, and when the radio frame is transmitted from the second other communication device, one or more channels including the first channel are occupied in the second network.

7. The communication device according to claim 1, characterized in that the communication means sends the notification to the first other communication device instructing it to prohibit transmission of wireless frames when all of the channels available for communication between the communication device and the first other communication device are occupied by the second other communication device.

8. The communication device according to claim 1 , wherein the notification includes information indicating a period during which the second communication method should be used or a period during which transmission of the wireless frame is prohibited.

9. 2. The communication device according to claim 1, characterized in that the notification includes information specifying a channel among the second channels to be used to acquire a transmission right in the second communication method when instructing the first other communication device to use the second communication method.

10. A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for communicating with the first other communication device by using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel in a communication link constituted by a first channel used for participating in a first network established by a first other communication device and acquiring a transmission right and one or more second channels different from the first channel; the communication means uses the second communication method when it receives information instructing to use the second communication method in a response transmitted by a first other communication device in response to a wireless frame regarding the occupancy of one or more channels including the first channel transmitted by a second other communication device constructing a second network different from the first network, and does not transmit the wireless frame when it receives information instructing to prohibit transmission of the wireless frame in the response. A communication device comprising:

11. The communication device according to claim 10 , wherein the response includes information indicating a period during which the second communication method should be used or a period during which transmission of the wireless frame is prohibited.

12. A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for establishing a first network and communicating with a first other communication device participating in the first network; the communication means is a second network in which communication is performed using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel, in one communication link composed of a first channel used to acquire a transmission right and one or more second channels different from the first channel, and transmits a wireless frame regarding the occupancy of one or more channels including the first channel to a second other communication device constructing the second network different from the first network; the communication means communicates with the first other communication device using one or more channels including the first channel based on the transmission of the wireless frame; A communication device characterized in that the wireless frame is a wireless frame that, when the second other communication device receives the wireless frame and one or more channels including the first channel are occupied in the first network, causes the second other communication device to send an instruction to a third other communication device participating in the second network to use the second communication method or to prohibit the transmission of a wireless frame.

13. a radio frame related to occupancy of one or more channels including the first channel is a radio frame requesting occupancy of one or more channels including the first channel; The communication device according to claim 12, characterized in that when the communication means receives a response from the second other communication device indicating permission for occupancy of one or more channels including the first channel, it communicates with the first other communication device using one or more channels including the first channel.

14. The communication device according to claim 13 , wherein the response includes information indicating a period during which occupancy of one or more channels including the first channel is permitted.

15. The communication device according to claim 13, characterized in that, when the communication means receives a response from the second other communication device indicating that occupancy of one or more channels including the first channel is permitted, it transmits information indicating that occupancy of one or more channels including the first channel is permitted to the first other communication device.

16. The communication device according to claim 13, characterized in that the communication means does not communicate with the first other communication device using one or more channels including the first channel when it receives a response from the second other communication device indicating that occupancy of one or more channels including the first channel is not permitted.

17. The communication device according to claim 13, characterized in that the communication means performs contention-based channel access with the first other communication device in one or more channels including the first channel when it receives a response from the second other communication device indicating that occupancy of one or more channels including the first channel is not permitted.

18. The radio frame regarding the occupancy of one or more channels including the first channel is a radio frame that declares the occupancy of one or more channels including the first channel, The communication device according to claim 12, characterized in that the communication means communicates with the first other communication device using one or more channels including the first channel after a predetermined time has elapsed, even if no response is received from the second other communication device.

19. 20. The communication device according to claim 18, characterized in that a radio frame declaring occupation of one or more channels including the first channel is also transmitted to the first other communication device.

20. 20. The communication device according to claim 18, wherein the predetermined time is determined based on a period during which the second other communication device transmits an instruction to the third other communication device to use the second communication method or to prohibit transmission of wireless frames, and a predetermined Interframe Space (IFS).

21. The communication device according to claim 12, characterized in that, when the communication means receives a request from the second other communication device, it transmits a radio frame regarding the occupancy of one or more channels including the first channel to the first other communication device.

22. A communication device that performs communication in accordance with the IEEE 802.11 standard series, a communication means for participating in a first network established by a first other communication device and communicating with the first other communication device; The communication means includes: transmitting a request to the first other communication device for occupation of one or more channels including the first channel; A second network in which communication is performed using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel, in one communication link composed of the first channel for acquiring a transmission right and one or more second channels different from the first channel, and when one or more channels including the first channel are occupied by the first other communication device transmitting a wireless frame regarding the occupancy of one or more channels including the first channel to a second other communication device constructing a second network different from the first network, communication is performed with the first other communication device using one or more channels including the first channel. A communication device comprising:

23. The communication device according to claim 22, characterized in that, when the communication means receives a notification from the first other communication device that the first other communication device is permitted to occupy one or more channels including the first channel, it communicates with the first other communication device using one or more channels including the first channel.

24. a radio frame regarding occupancy of one or more channels including the first channel, which is transmitted from the first other communication device to the second other communication device, is a radio frame declaring occupancy of one or more channels including the first channel; 23. The communication device according to claim 22, wherein the communication means communicates with the first other communication device using one or more channels including the first channel after a predetermined time has elapsed since the wireless frame was transmitted.

25. 25. The communication device according to claim 24, wherein the predetermined time is determined based on a period during which the second other communication device transmits an instruction to a third other communication device participating in the second network to use the second communication method or to prohibit transmission of wireless frames, and a predetermined Interframe Space (IFS).

26. A communication method is executed by a communication device that performs communication in accordance with the IEEE 802.11 series of standards with a first other communication device belonging to a first network, using either a first communication method that uses at least a first channel used for constructing a first network and acquiring a transmission right, or a second communication method that does not use the first channel but uses one or more of the second channels, in one communication link that is composed of the first channel and one or more second channels different from the first channel, the method comprising: receiving a wireless frame related to the occupancy of one or more channels including the first channel from a second other communication device constructing a second network different from the first network, and when one or more channels including the first channel are occupied in the second network, transmitting a notification to the first other communication device instructing the use of the second communication method or instructing prohibition of transmission of wireless frames; A control method comprising:

27. A communication method is executed by a communication device that performs communication in accordance with the IEEE 802.11 standard series with a first other communication device, using either a first communication method that uses at least a first channel, the first channel being used to participate in a first network established by the first other communication device and obtain a transmission right, and one or more second channels different from the first channel, in one communication link, the first communication method using the first channel, or a second communication method that does not use the first channel but uses one or more of the second channels, the method comprising: using the second communication method when information instructing to use the second communication method is received in a response transmitted by a first other communication device to a wireless frame regarding the occupancy of one or more channels including the first channel transmitted by a second other communication device constructing a second network different from the first network; not transmitting the wireless frame when receiving information instructing to prohibit the transmission of the wireless frame in the response; A communication method comprising:

28. A communication method executed by a communication device that establishes a first network and communicates with a first other communication device participating in the first network in accordance with the IEEE 802.11 standard series, comprising: A second network in which communication is performed using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel in one communication link composed of a first channel used to acquire a transmission right and one or more second channels different from the first channel, and transmitting a wireless frame regarding the occupancy of one or more channels including the first channel to a second other communication device constructing the second network different from the first network; performing communication with the first other communication device using one or more channels including the first channel based on the transmission of the wireless frame; Including, The communication method, characterized in that the wireless frame is a wireless frame that, when the second other communication device receives the wireless frame and one or more channels including the first channel are occupied in the first network, causes the second other communication device to send an instruction to a third other communication device participating in the second network to use the second communication method or to prohibit the transmission of a wireless frame.

29. 1. A communication method executed by a communication device that participates in a first network established by a first other communication device and communicates with the first other communication device in accordance with the IEEE 802.11 standard series, comprising: transmitting a request to the first other communication device for occupation of one or more channels including the first channel; a second network in which communication is performed using either a first communication method using at least the first channel or a second communication method using one or more of the second channels without using the first channel, in one communication link composed of the first channel for acquiring a transmission right and one or more second channels different from the first channel, and when one or more channels including the first channel are occupied by the first other communication device transmitting a wireless frame regarding the occupancy of one or more channels including the first channel to a second other communication device constructing a second network different from the first network, communication is performed with the first other communication device using one or more channels including the first channel; A communication method comprising:

30. A program for causing a computer to function as each of the means possessed by the communication device according to any one of claims 1 to 25.

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