Communication device, control method, and program

Abstract

To provide a communication device and a program for notifying of capability information designating a multi-primary channel (M-PCH).SOLUTION: A communication device performs communication conforming to the IEEE802.11 series, and transmits a MAC frame including capability information for specifying at least one channel selected from a plurality of channel candidates assumed to be used while being coupled to a specific primary channel in an idle state, the at least one channel allowed to perform channel access and used for communication even when the specific primary channel enters a busy state. When the specific primary channel is detected to be in the busy state, and the selected at least one channel is detected to be in the idle state, the communication device performs frame communication with another communication device through the at least one channel detected to be in the idle state.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to communication control in a wireless LAN. [Background technology]

[0002] In recent years, with the development of information and communication technology, Internet usage has been increasing year by year, and various communication technologies are being developed to meet the increasing demand. Among them, wireless LAN (local area network (WLAN)) technology has improved the throughput of Internet communications such as packet data, voice, and video using mobile terminals in public places as well as private spaces such as homes and factories.

[0003] The development of WLAN technology has been played an important role by numerous standardization efforts by the standardization organization, IEEE (Institute of Electrical and Electronics Engineers) 802. IEEE802.11 is known as one of the standard WLAN communication standards, and IEEE802.11a / b / g / n / ac has also been released, and the latest standard, IEEE802.11ax, has also been released as a draft standard, and various technological developments are currently being actively carried out (Patent Document 1).

[0004] In 2018, the IEEE802.11be Task Group (TG) was launched as a successor to IEEE802.11ax to further improve throughput, reliability, and latency. One of the goals of the IEEE802.11be TG is reliable low-latency (RLL) communications, which is expected to be used in real-time applications such as remote control of industrial robots, augmented reality / virtual reality, games, and drones. In such use cases, the reliability and latency conditions vary depending on the environment, but the latency order is 1 to 10 ms, and the reliability (transmission success rate) must be 99.9999%. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-50133 A Summary of the Invention [Problem to be solved by the invention]

[0006] To realize RLL communication, it is necessary to reduce the delay of channel access of wireless LAN by using communication resources effectively. However, in an environment where multiple BSSs (Basic Service Sets) overlap, for example, an OBSS (Overrapping BSS) environment, it is not easy to occupy a channel or secure an available channel, so it is not easy to realize RLL communication. Therefore, a channel access technology using multiple primary channels (multi-primary channels (M-PCH)) to utilize unused resources scattered across multiple channels / bands is being considered in IEEE802.11be.

[0007] However, no mechanism has been proposed so far for notifying capability information specifying a multi-primary channel (M-PCH).

[0008] The present invention has been made in view of the above-mentioned problems, and has an object to provide a mechanism for notifying capability information specifying a multi-primary channel (M-PCH). [Means for solving the problem]

[0009] As one means for achieving the above object, a communication device of the present invention is a communication device that performs communication in accordance with the IEEE 802.11 series, a first transmission control means for transmitting a MAC frame including capability information for identifying at least one channel that is selected from a plurality of channel candidates that are expected to be used in combination with a specific primary channel in an idle state, and that is permitted to be used for communication by channel access even when the specific primary channel is in a busy state; a second transmission control means for, when it is detected that the specific primary channel is busy and the selected at least one channel is idle, communicating a frame to another communication device via the at least one channel detected to be idle; A communication device comprising: Effect of the Invention

[0010] According to the present invention, a mechanism is provided for reporting capability information specifying a multi-primary channel (M-PCH). [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a network configuration in the present embodiment. [Diagram 2] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Diagram 3] FIG. 2 illustrates an example of a functional configuration of a communication device. [Figure 4] 11 is a flowchart showing a process executed by an AP when a STA is connected. [Diagram 5] 11 is a flowchart showing a process executed by an AP to start data communication. [Figure 6] This is a message sequence diagram between AP and STA during DL communication. [Figure 7] FIG. 11 is a message sequence diagram between an AP and a STA during UL communication. [Figure 8] 13 is a flowchart of a process for determining whether a primary channel is free / busy. [Figure 9] FIG. 11 is a diagram illustrating an example of capability information of the M-PCH method. [Figure 10] FIG. 13 is a diagram illustrating an example of setting values ​​of capability information of the M-PCH method. [Figure 11] 1 is a diagram illustrating an example of specifying multiple primary channels in the 5 GHz band. [Figure 12] FIG. 13 is a diagram showing another example of the capability information of the M-PCH method. [Figure 13] FIG. 13 is a diagram showing another example of the capability information of the M-PCH method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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.

[0013] [Network configuration example] FIG. 1 shows an example of the configuration of a network in this embodiment. FIG. 1 shows networks BSS (Basic Service Set) 101 and BSS 111, which are configured by two access points (AP 102, AP 112) and two stations (STA 103, STA 113) as communication devices. As shown in FIG. 1, the network formed by AP 102 is indicated by BSS 101, and the network formed by AP 112 is indicated by BSS 111. In this embodiment, STA 113, which constitutes BSS 111, can transmit and receive frames to and from AP 112, and STA 103, which constitutes BSS 101, can transmit and receive frames to and from AP 102. In addition, STA 103 is in an OBSS (Overrapping BSS) environment in which it is subject to interference from a wireless channel used by AP 112 of the adjacent BSS 111. For this reason, the primary channel available in BSS 101 can be used in BSS 111 at the same time by STA 103.

[0014] Note that the network configuration shown in FIG. 1 is just an example, and the following discussion can be applied to a network (BSS) including many communication devices in a wider area, and to the positional relationships of various wireless communication devices.

[0015] [Communication device configuration] (Hardware configuration example) 2 shows an example of a hardware configuration of a communication device (APs 102, 112 and STAs 103, 113 in the example of the network configuration in FIG. 1) in this embodiment. The communication device includes, as an example of the hardware configuration, a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207.

[0016] The storage unit 201 is configured with a ROM and / or a RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. ROM stands for Read Only Memory, and RAM stands for Random Access Memory. Note that, in addition to memories such as ROM and RAM, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used as the storage unit 201.

[0017] The control unit 202 is configured with, for example, a processor such as a CPU or MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or the like. Here, CPU stands for Central Processing Unit, and MPU stands for Micro Processing Unit. The control unit 202 controls the entire communication device by executing a program stored in the storage unit 201. The control unit 202 may control the entire communication device in cooperation with the program stored in the storage unit 201 and an OS (Operating System). The control unit 202 controls the functional unit 203 to perform predetermined processing such as imaging, printing, and projection. The functional unit 203 is hardware for the communication device to perform predetermined processing. For example, when the communication device is a camera, the functional unit 203 is an imaging unit that performs imaging processing. Also, for example, when the communication device is a printer, the functional unit 203 is a printing unit that performs printing processing. Also, for example, when the communication device is a projector, the functional unit 203 is a projection unit that performs projection processing. The data processed by the function unit 203 may be data stored in the storage unit 201, or may be data communicated with another communication device via the communication unit 206 described later.

[0018] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user. Here, the output by the output unit 205 includes at least one of display on a screen, audio output by a speaker, vibration output, and the like. Note that both the input unit 204 and the output unit 205 may be realized by one module, such as a touch panel. The communication unit 206 controls wireless communication conforming to the IEEE802.11 series of standards and IP communication. In this embodiment, the communication unit 206 can execute processing conforming to at least the IEEE802.11be standard. The communication unit 206 also controls an antenna 207 to transmit and receive wireless signals for wireless communication. The communication device communicates content such as image data, document data, and video data with other communication devices via the communication unit 206. The antenna 207 is an antenna capable of receiving any of the sub-GHz band, the 2.4 GHz band, the 5 GHz band, and the 6 GHz band, and may be physically configured with one or more antennas to realize MIMO (Multi-Input and Multi-Output) transmission and reception.

[0019] (Example of functional configuration) 3 shows an example of the functional configuration of a communication device (APs 102, 112 and STAs 103, 113 in the example of the network configuration in FIG. 1) in this embodiment. The communication device has, as an example of its functional configuration, an M-PCH method determination unit 301, a capability information generation unit 302, a frame generation unit 303, a management frame communication unit 304, a data communication unit 305, a free / busy determination unit 306, a capability management unit 307, and a channel configuration unit 308.

[0020] The M-PCH method determination unit 301 determines the PCH method to be used for communication with the other communication device. The capability information generation unit 302 generates capability information to be included in a management frame to be transmitted. A management frame is a management frame defined in the IEEE802.11 series of standards, and is a MAC frame such as a Beacon frame, a Probe Request frame, a Probe Response frame, an Association Request frame, an Association Response frame, a Reassociation Request frame, and a Reassociation Response frame. In this embodiment, the capability information generation unit 302 generates / updates capability information that specifies an M-PCH method (hereinafter, capability information of the M-PCH method), which will be described later with reference to FIG. 9. The capability information of the M-PCH method can include information indicating the support status of the PCH method (PCH support field 904 in FIG. 9, which will be described later) and information indicating whether each PCH can be used (M-PCH usability fields 905 to 913 in FIG. 9). The frame generation unit 303 performs control related to frame generation.

[0021] The management frame communication unit 304 performs control for transmitting and receiving the above-mentioned management frame. For example, when the STA connects to a network (BSS) managed by the AP, it transmits an Association Request frame, and the AP transmits an Association Response frame as a response. The data communication unit 305 performs control for transmitting and receiving data frames using a channel (communication band) configured by the channel configuration unit 308. The free / busy determination unit 306 performs free / busy determination for a plurality of primary channels. The determination is performed by the free / busy determination unit 306 transmitting and receiving an RTS (Request To Send) message or a CTS (Clear To Send) message, which are control frames in the IEEE802.11 series of standards. The capability management unit 307 performs management such as storing capability information in the storage unit 201. In addition, the capability management unit 307 checks the PCH method supported by its own communication device at any timing. The channel configuration unit 308 configures a channel (communication band) used by the data communication unit 305 for communication of data frames. For example, the channel configuration unit 308 selects (determines) a primary channel, and then configures a communication band by combining the primary channel with a secondary channel adjacent to the primary channel (channel bonding). At this time, the channel configuration unit 308 may select a primary channel that can configure a wider bandwidth communication channel for high-speed data transmission as a condition for selecting (determining) the primary channel. Also, the channel configuration unit 308 may select a primary channel that satisfies conditions such as immediate response and low latency and high reliability that are essential for a network with time constraints. Also, the channel configuration unit 308 may be configured to select a primary channel from among multiple available channels in each frequency band (2.4 GHz, 5 GHz, 6 GHz, etc.) according to the predetermined condition.

[0022] Here, an example of capability information of the M-PCH scheme will be described with reference to Fig. 9. Fig. 9 is a diagram showing an example of capability information of the M-PCH scheme (M-PCH capability element). Like other information elements defined in the IEEE802.11 series of standards, the M-PCH capability element is composed of an Element ID field, a Length field, and information specific to the Element. The Element ID field 901 stores information for identifying the Element. The Length field 902 stores information indicating the data length of the Element. The M-PCH capability Info field 903 is information specific to the Element, and includes information (field 904) indicating the support status of the PCH scheme and information (fields 905 to 913) indicating whether each of the M-PCH channels can be used. The PCH support field 904 includes 2-bit information indicating the support status of the PCH scheme, and the M-PCH usability fields 905 to 913 include 1-bit information indicating whether each of the M-PCH channels can be used (described later with reference to Fig. 10). M-PCH 1 to M-PCH 9 are exemplary primary channels that can be used in the 5 GHz band and can be specified in this embodiment, and will be described later with reference to Fig. 11. The Reserve field 914 is an unused (reserved) portion of 5 bits to accommodate future expansion.

[0023] 9, the M-PCH capability Info field 903 is described as being two octets (16 bits), but the field name and bit position / size are not limited to this example. For example, similar information may be stored with different field names, in different orders, or in different sizes.

[0024] An example of different forms of capability information of the M-PCH scheme will be described with reference to Fig. 12 and Fig. 13. First, in Fig. 12, an Element ID field 901 and a Length field 902 are the same as those in Fig. 9, but the data length coded in the Length field 902 for information setting is 3 octets. Also, an M-PCH capability Info field 1201 is information specific to an Element, and includes the support status (fields 1202 to 1210) of the PCH scheme corresponding to each of M-PCH 1 to M-PCH 9. The PCH support fields 1202 to 1210 are 2-bit information indicating the support status of the PCH scheme, and are the same as the information (field 904) indicating the support status of the PCH scheme in Fig. 9 (described later with reference to Fig. 10). Since M-PCH 1 to M-PCH 9 are the same as those in Fig. 9, description thereof will be omitted. A Reserve field 1211 is an unused (reserved) portion of 6 bits to accommodate future extensions.

[0025] FIG. 13 is another example of a different form of capability information of the M-PCH scheme, similar to FIG. 9 and FIG. 12. In FIG. 13, the Element ID field 901 and the Length field 902 are similar to those in FIG. 9 and FIG. 12, but the data length coded in the Length field 902 for information setting is 6 octets. Also, the M-PCH capability Info field 1301 is information specific to the Element, and includes individual information (fields 1302 to 1307) of the available primary channels M-PCH 1 to 4, 7, and 8. At this time, the available primary channels M-PCH 1 to 4, 7, and 8 reflect the result of the free / busy determination process by the free / busy determination unit 306, and the details of this process will be described later with reference to FIG. 8. The M-PCH individual information fields 1302 to 1307 are 1-octet information indicating the support status of the PCH scheme, and are composed of 6 bits of the channel number field 1308 and 2 bits of information indicating the support status of the PCH scheme. The 2-bit information field 1309 indicating the support status of the PCH method is similar to the information (fields 904 and 1202 to 1210) indicating the support status of the PCH method in FIGS. 9 and 12 (described later with reference to FIG. 10).

[0026] FIG. 10 shows an example of bit values ​​set in the PCH support fields 904 and 1202 to 1210 and the M-PCH usability fields 905 to 913 in FIG. 9, FIG. 12, and FIG. 13. In FIG. 10, a table 1001 shows the relationship between the bit values ​​set in the PCH support fields 904 and 1202 to 1210 and 1309 and the support contents corresponding to the bit values. A bit value of 00 indicates that neither the conventional method using only one (Single) primary channel (S-PCH method) nor the multi-primary channel (M-PCH method) is supported. A bit value of 01 indicates that only the S-PCH method is supported. A bit value of 10 indicates that only the M-PCH method is supported. A bit value of 11 indicates that both methods are supported. A table 1002 shows the relationship between the bit values ​​set in the M-PCH usability fields 905 to 913 and the usability corresponding to the bit values. A bit value of 1 indicates that the channel can be used as a primary channel, and a bit value of 0 indicates that the channel cannot be used. Note that the setting values ​​for each information element are not limited to this example, and similar information may be stored with different field names, in different orders, or in different sizes.

[0027] FIG. 11 is a diagram for explaining an example of specifying multiple primary channels in the 5 GHz band (W52, W53, W56). M-PCH 1 to M-PCH 9 are multiple multiple primary channels available in the 5 GHz band, and are frequency channels with channel numbers 36, 44, 52, 60, 100, 108, 116, 124, and 132 and a bandwidth of 20 MHz. A basic example of specifying primary channels is an example of specifying nine M-PCHs (M-PCH 1 to M-PCH 9) assuming the use of 40+40 MHz. In this case, a frequency band combining 40+40 MHz is used. Specifically, when any one of M-PCH 1 to M-PCH 9 is selected (determined) as the primary channel, the adjacent channel is combined as a secondary channel and used (40+40 MHz).

[0028] As a specification of M-PCH, the M-PCH to be specified may be limited in order to clearly indicate the band to be used (80+80MHz, 160+160MHz). As an example, a specification example 1101 is an example of specification of four multi-primary channels, M-PCH 1, M-PCH 3, M-PCH 5, and M-PCH 7, assuming the use of 80+80MHz. At this time, the channel configuration unit 308 selects a primary channel to be used from the four primary channels according to the usage status of the adjacent primary channels. For example, when the adjacent channel (M-PCH 2 / M-PCH 4) of W52 (M-PCH 1)+W53 (M-PCH 3) is unavailable, it is configured to specify W56 (M-PCH 5, M-PCH 7). Similarly, if the primary channel of W56 (M-PCH 5, M-PCH 7) is unavailable, a band of 80+80 MHz is configured using the primary channel of W52 or W53. Also, specification example 1102 is a specification example of two multi-primary channels, M-PCH 1 and M-PCH 5, assuming the use of 160+160 MHz.

[0029] [Processing flow] Next, the flow of processing executed by each device in a communication system configured by STA 103 (communication partner device) and AP 102 (communication device) will be described with reference to Fig. 4 to Fig. 9. Fig. 4 is a flowchart showing processing executed by AP 102 when STA 103 connects to AP 102. Note that the flowchart shown below can be realized by control unit 202 executing a control program stored in storage unit 201, and executing calculations and processing of information and control of each piece of hardware.

[0030] First, the management frame communication unit 304 of the AP 102 acquires the M-PCH capability information of the STA 103 (see FIG. 11) (S401). The M-PCH capability information can be acquired from a Probe Request frame that the STA 103 transmits before connection or an Association Request frame that the STA 103 transmits when connecting. At this time, the AP 102 may broadcast a Beacon frame including the M-PCH capability information of the AP 102 on multiple primary channels before receiving the Probe Request frame or the Association Request frame.

[0031] Next, the M-PCH scheme determination unit 301 of the AP 102 determines the PCH scheme to be used based on the M-PCH scheme capability information of the STA 103 acquired in S401 (S402). In this embodiment, the M-PCH scheme determination unit 301 makes this determination based on the bit value (FIG. 10) set in the PCH support field 904 in the M-PCH scheme capability information included in the received management frame. For example, the M-PCH scheme determination unit 301 can determine to use the M-PCH scheme when the STA 103 can only use the M-PCH, and the S-PCH scheme when the STA can only use the S-PCH scheme. In addition, when the STA 103 can use both the M-PCH scheme and the S-PCH scheme, the M-PCH scheme determination unit 301 may determine the PCH scheme to be used according to the characteristics (application characteristics) of the data to be transmitted and received from the STA 103. For example, when the data to be transmitted and received is a small amount of data transmitted periodically, such as sensor data, the S-PCH method may be selected since this is different from time-constrained communication such as RLL communication. Also, when the application of the transmitted and received data requires real-time operation, such as games or industrial robots, that is, it is an application with time constraints, the M-PCH method may be selected. Information regarding the characteristics (application characteristics) of data transmitted and received with the STA can be notified by the management frame of IEEE802.11. Also, when the number of users is large, the overhead in RLL communication becomes large, so the M-PCH method may be selected when the number of STAs participating in the network formed by the AP exceeds a predetermined threshold, regardless of the information indicated by the received capability information.

[0032] After determining the PCH method to be used, the capability information generating unit 302 of the AP 102 judges whether the determined PCH method is the M-PCH method. If the determined PCH method is not the M-PCH method (the S-PCH method) (NO in S403), the process ends. On the other hand, if the determined PCH method is the M-PCH method (YES in S403), the capability information generating unit 302 generates capability information of the M-PCH designated method (S404). The capability information generated in S404 is referred to as the first capability information. The first capability information includes information on the PCH method determined in S403 in the PCH support field 904. Next, the capability information generating unit 302 generates a management frame including the first capability information, and the management frame communicating unit 304 transmits the management frame (notifies the STA 103 of the first capability information) (S405). Thereafter, the capability management unit 307 of the AP 102 stores the first capability information in the storage unit 201 (S406).

[0033] 5 is a flowchart of a process executed by the AP 102 to start data communication after notifying the STA 103 of the first capability information (S405 in FIG. 4). The capability management unit 307 acquires the first capability information stored in the storage unit 201, and checks the information of the determined PCH method, that is, the PCH bit value in the PCH support field 904. If the determined PCH method is the M-PCH method (YES in S501), the process branches to S504. If the determined PCH method is not the M-PCH method (NO in S501), the capability management unit 307 checks whether the AP 102 supports the S-PCH method (S502). If the S-PCH method is supported (YES in S502), the S-PCH method is selected as the primary channel (S503), and the process branches to S507. For example, assume that 36ch is specified as the primary channel for the S-PCH method. In this case, in S507, the channel configuration unit 308 configures a total of 40 MHz communication band of 20 MHz + 20 MHz for data communication by combining the adjacent 40ch channels as secondary channels. Also, if the S-PCH method is not supported (NO in S502), the process ends.

[0034] In S504, the free / busy determination unit 306 performs free / busy determination on one primary channel (hereinafter, the target channel) of a plurality of primary channels (see the number of M-PCH availability fields 905 to 913 in FIG. 11) designated by the first capability information stored in the storage unit 201. For this determination, the free / busy determination unit 306 transmits an RTS (Request To Send) message, which is a control frame. When the STA 103 receives the RTS on the target channel, it performs carrier sense on the target channel. If the target channel is not busy as a result, the STA 103 transmits a CTS (Clear To Send) message, which is a control frame, to the AP 102 after a SIFS (Short Inter Frame Space) period has elapsed. The free / busy determination unit 306 of the AP 102 confirms reception of a CTS, which is a response to the RTS, on the target channel to which the RTS was transmitted, and if reception is confirmed, determines that the target channel is an available primary channel. At this time, if the free / busy determination unit 306 cannot confirm the reception of the CTS in the target channel, it determines that the target channel cannot be used for channel access. Next, the capability information generation unit 302 generates capability information of the M-PCH designation method. The capability information generated in S504 is called second capability information. In the second capability information, a bit value corresponding to free / busy is included in the M-PCH availability field 905-913 corresponding to the target channel. The free / busy determination unit 306 performs free / busy determination for all the designated primary channels (NO in S504, S504), and after the determination is completed (S505), the process proceeds to S506. In the above description, the result of the free / busy determination for one primary channel is reflected in the second capability information, and then the same process is performed for another target channel. However, the second capability information may be configured to be generated after the free / busy determination for all primary channels is performed.

[0035] Here, the free / busy determination process by the free / busy determination unit 306 will be described with reference to Fig. 8. Fig. 8 is a flowchart of the free / busy determination process. In the case of downlink (DL) communication from the AP 102 to the STA 103, the AP 102 is Tx and the STA 103 is Rx. In the case of uplink (UL) communication from the STA 103 to the AP 102, the STA 103 is Tx and the AP 102 is Rx. The RTS is a control frame message sent from the transmitting side to the receiving side to inquire about data transmission, and the CTS is a control frame returned to the transmitting side as a response to the RTS, indicating permission to transmit. The BUSY indicates that the channel of the RTS transmitted from the Tx is being used by the Rx. The SIFS is the carrier sense waiting time when returning the CTS after receiving the RTS. Here, we show an example of determining whether a channel is free (available) for nine multi-primary channels intended for bonding (channel bonding) of 40+40MHz or more (80+80MHz, 160+160MHz). Figure 8 shows that the determination result shows that when an RTS is sent, M-PCH 5, M-PCH 6, and M-PCH 9 are in the BUSY state, and CTS cannot be confirmed on those channels.

[0036] Returning to FIG. 5, in S506, the capability management unit 307 stores the generated second capability information in the storage unit 201. Also, in S506, the capability information generation unit 302 generates a management frame including the second capability information, and the management frame communication unit 304 transmits the management frame (notifies the STA 103 of the second capability information). When proceeding from S506 to S507, the channel configuration unit 308 performs channel access to the STA 103 by the M-PCH method based on the second capability information. Then, the AP 102 selects (determines) a primary channel to be used for transmitting and receiving data frames from among M-PCHs 1 to 9 with the STA 103. Thereafter, the channel configuration unit 308 combines the selected primary channel with a channel adjacent to the primary channel as a secondary channel to configure a communication band to be used for data communication. For example, when M-PCH 1 is selected, the channel is combined with the adjacent M-PCH 2 channel as a secondary channel to configure a communication band of 40+40 MHz. In response to this, the STA 103 transitions to a data communication in progress state in which the STA 103 receives the data frame transmitted by the AP 102 in the above-mentioned 40+40 MHz communication band.

[0037] When the process proceeds from S506 to S507, the channel configuration unit 308 may select the primary channel based on any condition. For example, the channel configuration unit 308 may select the primary channel based on at least one of the transmission bandwidth, reception field strength, signal-to-noise ratio (SNR), channel transmission capacity calculated from the bandwidth and SNR, and frequency of use estimated from the channel usage status during a certain period of time that can be secured by channel bonding. That is, for example, the channel configuration unit 308 may select a channel that maximizes the transmission bandwidth that can be secured by channel bonding (channel bonding). The channel configuration unit 308 may also select a channel with the strongest reception field strength or a channel with the best signal-to-noise ratio (SNR). Furthermore, the channel configuration unit 308 may select a channel with a large channel transmission capacity calculated from the bandwidth and SNR, or a channel based on vacant channel information estimated from the channel usage status during a certain period of time. The selection conditions for these primary channels may be any one of the above conditions or a combination of multiple conditions.

[0038] 5 is a flowchart of the process executed by the AP 102, the process executed by the STA 103 can be similarly realized by replacing the AP 102 with the STA 103, and therefore a description thereof will be omitted.

[0039] Next, with reference to Fig. 6 and Fig. 7, a communication sequence between AP102 and STA103 during DL communication and UL communication will be described. Fig. 6 is a sequence diagram between AP102 and STA103 during DL communication. M601 to M603 are scanning processes for STA103 to acquire network information of AP102. In M601, AP102 broadcasts a Beacon frame including network information of AP102 to STA103 in the network of BSS101. In M602, STA103 transmits a Probe Request frame inquiring about network information of AP102, and in M603, AP102 transmits a Probe Response frame as a response. The STA103 may obtain the network information of the AP102 by receiving a Beacon frame (M601) transmitted by the AP102, or may obtain the network information of the AP102 by actively transmitting a Probe Request frame (M602) and receiving a Probe Response frame (M603) from the AP102. The Beacon frame and the Probe Response frame may include the capability information of the M-PCH method of the AP102 (see FIG. 11). In particular, the Beacon frame including the capability information of the M-PCH method may be broadcast on a plurality of primary channels. Also, the Probe Request may include the capability information of the M-PCH method of the STA103 (see FIG. 11). Through these processes, the STA103 and the AP102 can exchange their own capability information of the M-PCH method.

[0040] In M604, the STA103 transmits an Association Request frame to connect to the network of the BSS101, and in M605, the AP102 transmits an Association Response frame indicating the connection result. The Association Request frame and the Association Response frame can also include M-PCH capability information. The STA103 may determine the M-PCH capability information to be included in the Association Request frame based on the M-PCH capability information of the AP102 acquired by the scanning process. For example, even if the STA103 can use the S-PCH and M-PCH methods, if the AP102 can only use the M-PCH method, the capability information of the M-PCH method to be included in the Association Request frame may indicate that only the M-PCH method can be used. Similarly, the AP102 may determine the M-PCH capability information to be included in the Association Response frame based on the M-PCH capability information of the STA103 included in the Association Request frame. In this example, as shown in FIG. 4, the AP 102 decides to adopt the M-PCH scheme and generates first capability information (S404), and notifies the STA 103 of the first capability information in a management frame in M606 (S405).

[0041] M607 after a data transmission request by a user or the like is a message sequence related to free / busy determination processing of multiple primary channels. The processing performed in M607 is the same as the processing contents described in S504 to S506 of FIG. 5, so the description will be omitted. Note that the message sequence related to free / busy determination processing of the primary channel using RTS and CTS is described in FIG. 8. In M608, the AP 102 transmits a management frame 2 including the second capability information generated based on the processing of M607 to the STA 103. In M609, as described in S507 of FIG. 5, the AP 102 transmits a data frame of DL communication to the STA 103 using the communication band in which the primary channel and the secondary channel are combined. At this time, since the connection sequence (M601 to M605) has been completed in advance, the AP 102 does not need to transmit the Beacon frame (M601) on the primary channel used for the channel combination.

[0042] FIG. 7 is a sequence diagram between STA103 and AP102 during UL communication. The scanning process of M601 to M603, the connection process of STA103 of M604 to M605, and the transmission and reception process related to the transmission of the management frame of M606 are the same as those in FIG. 6, so the description will be omitted. M701 after a data transmission request from a user or the like is a message sequence related to the free / busy determination process of the multiple primary channels in STA103. Based on the first capability information received in M606, STA103 transmits an RTS message, which is a control frame, to each of the multiple available primary channels to determine whether the channels are free or busy. Next, when AP102 receives an RTS from each primary channel, it performs carrier sense of the corresponding channel. As a result, if the corresponding channel is not busy, it transmits a CTS message, which is a control frame, to STA103 after the lapse of the SIFS period. The STA 103 confirms receipt of a CTS, which is a response to the RTS, on each primary channel on which the RTS was transmitted, and determines that the channel for which the reception has been confirmed is an available primary channel. The STA 103 also determines that a primary channel for which the reception of the CTS has not been confirmed is unavailable for channel access. The STA 103 generates second capability information based on the result of the determination. The message sequence related to the process of determining whether the primary channel is free / busy between the STA 103 and the AP 102 in the M701 is shown in FIG. 8.

[0043] When the STA103 completes the determination of whether all of the available primary channels are free / busy (YES in S505), the STA103 stores the second capability information in the storage unit 201. In M702, the STA103 transmits a management frame 2 including the second capability information obtained in the process of M701 and stored in the storage unit 201 to the AP102. In M703, as described in S507 of FIG. 5, the STA103 transmits a data frame of UL communication to the AP102 using the communication band in which the determined primary channel and secondary channel are combined. At this time, since the connection sequence (M601 to M605) has been completed in advance, the AP102 does not need to transmit the Beacon frame (M601) on the primary channel used for the channel combination.

[0044] As described above, according to this embodiment, the capability information of the multi-primary channel method can be exchanged between the STA and the AP. This reduces the delay in channel access even in an environment where it is not easy to occupy a channel or secure an available channel, and provides an IEEE802.11-compliant wireless environment suitable for applications that meet the requirements of high reliability and low delay.

[0045] [Other embodiments] 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.

[0046] 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]

[0047] 101, 111 Network BSS, 103, 113 STA, 102, 112 AP

Claims

1. A communication device that performs communication in accordance with the IEEE 802.11 series, a first transmission control means for transmitting a MAC frame including capability information for identifying at least one channel selected from a plurality of channel candidates that are expected to be used in combination with a specific primary channel in an idle state, the at least one channel being permitted to be used for communication by channel access even when the specific primary channel is in a busy state; a second transmission control means for, when it is detected that the specific primary channel is busy and the selected at least one channel is idle, communicating a frame to another communication device via the at least one channel that is detected to be idle; A communication device comprising:

2. The communication device according to claim 1, characterized in that the second transmission control means communicates frames with other communication devices using a bonding channel having a bandwidth greater than 20 MHz that combines one channel detected to be in an idle state with an adjacent channel.

3. The communication device functions as an access point; the first transmission control means, based on the number of stations connected to a network formed by the communication device, determines whether to transmit the MAC frame by including the capability information therein, or whether to transmit the MAC frame by including the capability information therein, or 2) whether to transmit the MAC frame by including another capability information that does not include the capability information and stores information different from the capability information, the another capability information including information indicating that a specific communication function is not supported but does not include information specifying a channel that is permitted to be used for communication by channel access even when the specific primary channel is in a busy state; 3. The communication device according to claim 1, wherein the capability information further includes information indicating that the specific communication function is supported.

4. the first transmission control means further comprises a determination means for determining whether or not to use the specific communication function based on the number of stations connected to a network formed by the communication device; When the determination means determines that the specific function is to be used, the first transmission control means controls the MAC frame to be transmitted with other capability information that does not include the capability information and stores information different from the capability information; A communication device as described in any one of claims 1 to 3, characterized in that when the decision means decides not to use the specific function, the communication device does not communicate frames to other communication devices using only channels that do not include the specific primary channel and are composed only of channels of the multiple channel candidates that are expected to be used in combination with the specific primary channel.

5. A control method executed by a communication device that performs communication in accordance with the IEEE 802.11 series, comprising: Transmitting a MAC frame including capability information for identifying at least one channel selected from a plurality of channel candidates that are expected to be used in combination with a specific idle primary channel, the at least one channel being permitted to be used for communication by channel access even when the specific primary channel is in a busy state; when it is detected that the specific primary channel is busy and the selected at least one channel is idle, communicating a frame to another communication device via the at least one channel that is detected to be idle; A control method comprising:

6. A computer of a communication device that performs communication in accordance with the IEEE 802.11 series, a first transmission control means for transmitting a MAC frame including capability information for identifying at least one channel selected from a plurality of channel candidates that are expected to be used in combination with a specific primary channel in an idle state, the at least one channel being permitted to be used for communication by channel access even when the specific primary channel is in a busy state; a second transmission control means for, when it is detected that the specific primary channel is busy and the selected at least one channel is idle, communicating a frame to another communication device via the at least one channel that is detected to be idle; A program characterized by causing the program to function as a

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