Wireless communication system, access point, wireless communication method, and program

Abstract

To change channels without switching modes when a radar wave is detected.SOLUTION: A wireless communication system 1 is a WDS (Wireless Distribution System) using a predetermined band and includes a root access point 10 and one or more repeater access points 20. When any of the one or more repeater access points 20 detects a radar wave using a frequency of a selected channel, the repeater access point 20 transmits a RCSA (Reverse Channel Switch Announcement) toward the root access point 10. Upon receiving the RCSA, the root access point 10 transmits, using a first channel, a beacon that includes a CSA indicating that the selected channel will be changed from the first channel to a second channel, and changes the selected channel from the first channel to the second channel. Upon receiving the beacon that includes the CSA, one or more repeater access points 20 change the selected channel from the first channel to the second channel.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a wireless communication system, an access point, a wireless communication method performed by the wireless communication system, and a program used by the access point. [Background technology]

[0002] In Japan's Radio Law, for example, some 5GHz bands must be shut down when weather radar waves are detected, and these 5GHz bands are distinguished from other 5GHz bands (channels) as DFS (Dynamic Frequency Selection) bands. In WDS (Wireless Distribution System) that use such DFS bands, a function (DFS function) is required to change the channel in use to another channel when radar waves using the frequency band of a channel in use are detected.

[0003] Conventionally, in a WDS that uses a specific band (DFS band), when a radar wave using the frequency band of a channel in use is detected, a technique for changing the channel in use to another channel is known, for example, as described in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-047333 A Summary of the Invention [Problem to be solved by the invention]

[0005] When using the technology described in Patent Document 1 to change the channel in use to another channel, the wireless base stations (access points) that make up the WDS need to switch between access point mode and station mode.

[0006] For this reason, when the channel to be used is changed to another channel using the technique described in Patent Document 1, it is necessary to incur a mode switching cost associated with the mode switching of the access point.

[0007] Therefore, an object of the present disclosure is to provide a communication system etc. in which, when radar waves using the frequency band of a channel in use are detected in a WDS using a specified band, the access points constituting the WDS can change the channel being used to another channel without switching modes. [Means for solving the problem]

[0008] A wireless communication system according to one embodiment of the present disclosure is a wireless communication system including a root access point located at the highest position in a wireless distribution system (WDS) using a predetermined band, and one or more repeater access points located below the root access point in the WDS, wherein the root access point alternatively selects one channel from among a plurality of channels in the predetermined band as a channel to be used for communication in the WDS, and includes a root AP communication unit that uses the selected channel to communicate with at least one of the one or more repeater access points, a root AP beacon unit that transmits a beacon using the selected channel, and a root AP radar wave detection unit that detects radar waves using the frequency band of the selected channel, and Each of the repeater APs includes a repeater AP communication unit that communicates with the root access point and / or at least one of the other repeater access points of the one or more repeater access points using the selected channel, a repeater AP radar wave detection unit that detects radar waves using a frequency band of the selected channel, and a repeater AP beacon unit that transmits and receives the beacon. When the repeater AP radar wave detection unit detects the radar wave, or when the repeater AP communication unit receives a Reverse Channel Switch (RCSA) signal from a lower repeater access point that is one level lower in the WDS among the one or more repeater access points, the repeater AP communication unitWhen the root AP communication unit receives a Channel Switch Announcement (CSA), the root AP communication unit transmits the RCSA to the root access point located one level higher in the WDS or to a higher level repeater access point located one level higher in the WDS among the one or more repeater access points, and when the root AP radar wave detection unit detects the radar wave or receives the RCSA in a case where the root AP communication unit selects a first channel of the plurality of channels as the selected channel, the root AP communication unit selects a second channel different from the first channel of the plurality of channels as a new selected channel in the WDS, and the root AP beacon unit uses the first channel to transmit a Channel Switch Announcement (CSA) indicating that the channel used for communication in the WDS will be changed from the first channel to the second channel. The repeater AP beacon unit transmits the beacon including a CSA (Certified Signal Announcing), and then changes the selected channel used for transmitting the beacon from the first channel to the second channel, and at the same time, the root AP communication unit changes the selected channel used for communication from the first channel to the second channel, and when the repeater AP beacon unit receives the beacon including the CSA, the repeater AP communication unit transmits the beacon including the CSA and then changes the selected channel used for communication from the first channel to the second channel.

[0009] In the wireless communication system configured as above, when any one of the one or more repeater access points detects radar waves using the frequency of the selected channel, that repeater access point transmits an RCSA toward the root access point.

[0010] Then, when the root access point receives the RCSA, it uses the first channel to transmit a beacon including a CSA indicating that the selected channel will be changed from the first channel to the second channel, and then changes the selected channel from the first channel to the second channel.

[0011] Then, one or more repeater access points change the selected channel from the first channel to the second channel after receiving the beacon that includes the CSA.

[0012] In this way, according to the wireless communication system of the above configuration, when radar waves using the frequency band of a channel in use are detected in a WDS using a specified band, a communication system is realized in which the access points constituting the WDS can change the channel being used to another channel without switching modes.

[0013] In addition, when the repeater AP beacon unit does not receive the beacon including the CSA within a specified period of time despite the repeater AP communication unit transmitting the RCSA due to the repeater AP radar wave detection unit detecting the radar waves, the repeater AP communication unit may suppress communication using the selected channel and search for channels used for communication in the WDS.

[0014] This means that even if a repeater access point that sent an RCSA becomes isolated from a WDS that uses a new channel reconstructed by the root access point because it fails to receive a beacon containing a CSA, it can search for the new channel and attempt to resolve its isolation from the WDS.

[0015] Furthermore, when the root AP communication unit selects the first channel as the selected channel, if the repeater AP beacon unit receives the beacon including the CSA, the repeater AP beacon unit transmits the beacon including the CSA using the first channel, and then changes the selected channel used for transmitting and receiving the beacon from the first channel to the second channel, and when the root AP communication unit changes the selected channel used for communication from the first channel to the second channel, the root AP communication unit performs Channel Availability Adjustment (CAC) from the time of the change. the root AP beacon unit may, when the selected channel used for transmitting the beacon is changed from the first channel to the second channel, suppress the transmission of the beacon using the second channel until the CAC period has elapsed from the time of the change; the repeater AP communication unit, when the selected channel used for communication is changed from the first channel to the second channel, suppress the communication using the second channel until the CAC period has elapsed from the time of the change; and the repeater AP beacon unit, when the selected channel used for transmitting the beacon is changed from the first channel to the second channel, suppress the transmission of the beacon using the second channel until the CAC period has elapsed from the time of the change.

[0016] This makes it possible, when the selected channel is changed from the first channel to the second channel, to suppress the use of the second channel until the CAC period has elapsed from the time of the change.

[0017] In addition, when transmitting the beacon including the CSA, the root AP beacon unit may transmit the beacon multiple times in succession at a first predetermined interval, when transmitting the beacon including the CSA, the repeater AP beacon unit may transmit the beacon multiple times in succession at the first predetermined interval, and when transmitting the RCSA, the repeater AP communication unit may transmit the RCSA multiple times in succession at a second predetermined interval.

[0018] This makes it possible to prevent missed reception of a beacon including a CSA and missed reception of an RCSA.

[0019] In addition, the root AP beacon unit may be configured to suppress further transmission of the beacon including the CSA if the root AP communication unit receives the RCSA after transmitting the beacon including the CSA, and the repeater AP communication unit may be configured to suppress further transmission of the RCSA if the repeater AP radar wave detection unit detects the radar wave after transmitting the RCSA and if the repeater AP communication unit receives the RCSA.

[0020] This makes it possible to suppress unnecessary retransmission of beacons including CSAs and unnecessary retransmission of RCSAs.

[0021] The predetermined band may be a band included in a DFS (Dynamic Frequency Selection) band.

[0022] This makes it possible to solve the problem of radar interference in WDS using channels in the DFS band.

[0023] An access point according to an embodiment of the present disclosure is a root access point in a wireless communication system including a root access point located at the highest position in a WDS using a predetermined band, and one or more repeater access points located below the root access point in the WDS, the root access point comprising: a root AP communication unit that alternatively selects one channel from a plurality of channels in the predetermined band as a channel to be used for communication in the WDS, and communicates with at least one of the one or more repeater access points using the selected selected channel; a root AP beacon unit that transmits a beacon using the selected channel; and a root AP radar wave detection unit that detects radar waves using the selected channel, and when the root AP communication unit selects a first channel from the plurality of channels as the selected channel, the root AP radar wave detection unit outputs a Reverse Channel Switch (RCSA) signal indicating that the root AP radar wave detection unit has detected the radar wave or that one of the one or more repeater access points has detected the radar wave. When the root AP communication unit receives a Channel Switch Announcement (CSA), the root AP communication unit selects a second channel from the multiple channels that is different from the first channel as a new selected channel in the WDS, and the root AP beacon unit uses the first channel to transmit the beacon including a Channel Switch Announcement (CSA) indicating that the channel to be used for communication in the WDS will be changed from the first channel to a second channel from the multiple channels that is different from the first channel, and then changes the selected channel to be used for transmitting the beacon from the first channel to the second channel, and at the same time, the root AP communication unit changes the selected channel to be used for communication from the first channel to the second channel.

[0024] According to an access point having the above configuration, when it receives an RCSA, it uses the first channel to transmit a beacon including a CSA indicating that the selected channel will be changed from the first channel to the second channel, and also changes the selected channel from the first channel to the second channel.

[0025] In this way, with an access point of the above configuration, which is a root access point in a WDS using a specified band, an access point is realized that can change the channel being used to another channel without switching modes when radar waves using the frequency band of a channel currently in use in the WDS are detected.

[0026] An access point according to one embodiment of the present disclosure is a wireless communication system including a root access point located at the highest position in a WDS using a predetermined band, and one or more repeater access points located below the root access point in the WDS, and each of the one or more repeater access points communicates with the root access point and / or at least one of the other repeater access points of the one or more repeater access points using a selected channel, which is one channel of a plurality of channels in the predetermined band alternatively selected by the root access point as a channel to be used for communication in the WDS. a repeater AP radar wave detection unit that detects radar waves using a frequency band of the selected channel, and a repeater AP beacon unit that receives a beacon transmitted using the selected channel, and when the root access point selects a first channel as the selected channel, the repeater AP communication unit transmits a Reverse Cross-Signal (RCSA) signal indicating that one of the one or more repeater access points has detected the radar wave when the repeater AP radar wave detection unit detects the radar wave or when the repeater AP communication unit receives a Reverse Cross-Signal (RCSA) signal indicating that one of the one or more repeater access points has detected the radar wave from a lower repeater access point that is located one level lower in the WDS among the one or more repeater access points. When the repeater AP beacon unit receives a Channel Switch Announcement (CSA), the repeater AP beacon unit transmits an RCSA indicating that the radar wave has been detected to the root access point located one level higher in the WDS or to a higher level repeater access point located one level higher in the WDS among the one or more repeater access points, and transmits a CSA (Channel Switch Announcement) indicating that the repeater AP beacon unit will change the channel used for communication in the WDS from the first channel to a second channel different from the first channel among the multiple channels.When the repeater AP beacon unit receives a beacon including the CSA (Certified Signal Announcement), the repeater AP beacon unit transmits a beacon including the CSA using the first channel, and then the repeater AP communication unit changes the selected channel used for communication from the first channel to the second channel.

[0027] According to the access point having the above configuration, when a radar wave using the frequency band of the selected channel is detected or when an RCSA is received, the access point transmits the RCSA to the root access point.

[0028] Then, after receiving the beacon including the CSA, the access point changes the selected channel from the first channel to the second channel.

[0029] In this way, by using an access point of the above configuration, which is one or more repeater access points in a WDS using a specified band, an access point is realized that can change the channel being used to another channel without switching modes when radar waves using the frequency band of a channel currently in use in the WDS are detected.

[0030] In addition, when the repeater AP beacon unit does not receive the beacon including the CSA within a specified period of time despite the repeater AP communication unit transmitting the RCSA due to the repeater AP radar wave detection unit detecting the radar waves, the repeater AP communication unit may suppress communication using the selected channel and search for channels used for communication in the WDS.

[0031] This means that even if a repeater access point that sent an RCSA becomes isolated from a WDS that uses a new channel reconstructed by the root access point because it fails to receive a beacon containing a CSA, it can search for the new channel and attempt to resolve its isolation from the WDS.

[0032] In addition, when the repeater AP communication unit changes the selected channel used for communication from the first channel to the second channel, it may suppress communication using the second channel until a CAC period has elapsed from the time of the change, and when the repeater AP beacon unit changes the selected channel used for transmitting the beacon from the first channel to the second channel, it may suppress transmission of the beacon using the second channel until the CAC period has elapsed from the time of the change.

[0033] As a result, when the selected channel is changed from the first channel to the second channel, the use of the second channel can be suppressed until the CAC period has elapsed from the time of the change.

[0034] In addition, when transmitting the beacon including the CSA, the repeater AP beacon unit may transmit the beacon multiple times in succession at a first predetermined interval, and when transmitting the RCSA, the repeater AP communication unit may transmit the RCSA multiple times in succession at a second predetermined interval.

[0035] This makes it possible to prevent missed reception of a beacon including a CSA and missed reception of an RCSA.

[0036] In addition, after transmitting the RCSA, the repeater AP communication unit may be configured to suppress further transmission of the RCSA if the repeater AP radar wave detection unit detects the radar wave and if the repeater AP communication unit receives the RCSA.

[0037] This makes it possible to suppress unnecessary retransmission of RCSA.

[0038] The predetermined band may be a band included in the DFS band.

[0039] This makes it possible to solve the problem of radar interference at WDS repeater access points using channels in the DFS band.

[0040] A wireless communication method according to one embodiment of the present disclosure is a wireless communication method performed by a wireless communication system including a root access point located at the highest position in a WDS using a predetermined band and one or more repeater access points located below the root access point in the WDS, the method including a root AP communication step of the root access point alternatively selecting one channel out of a plurality of channels in the predetermined band as a channel to be used for communication in the WDS and using the selected selected channel to communicate with at least one of the one or more repeater access points, a root AP beacon step of transmitting a beacon using the selected channel, a root AP radar wave detection step of detecting a radar wave using the frequency band of the selected channel, and a root AP communication step of the one or more repeater access points. The repeater AP communication step includes a repeater AP communication step of communicating with the root access point and / or at least one of the one or more repeater access points by using the selected channel, a repeater AP radar wave detection step of detecting a radar wave using a frequency band of the selected channel, and a repeater AP beacon step of transmitting and receiving the beacon, and in the repeater AP communication step, when the radar wave is detected in the repeater AP radar wave detection step, or in the repeater AP communication step, a reverse channel switch (RCSA) signal indicating that one of the one or more repeater access points has detected the radar wave is sent from a lower repeater access point that is one level lower in the WDS among the one or more repeater access points.When a root AP beacon step receives a beacon announcement (RCSA), the root AP transmits the RCSA to the root access point located one level higher in the WDS or to a higher level repeater access point located one level higher in the WDS among the one or more repeater access points. When a first channel of the plurality of channels is selected as the selected channel in the root AP communication step, a second channel different from the first channel is selected as a new selected channel in the WDS when the first channel is detected in the root AP radar wave detection step or the RCSA is received. In the root AP beacon step, the first channel is used to transmit a CSA (Channel Switch Announcement) indicating that the channel used for communication in the WDS is changed from the first channel to a second channel. a beacon including a CSA (Continued State Announcement), thereafter changing the selected channel used in the Root AP Beacon step from the first channel to the second channel, and at the same time changing the selected channel used in the Root AP Communication step from the first channel to the second channel; and in the Repeater AP Communication step, if the beacon including the CSA is received in the Repeater AP Beacon step, after transmitting the beacon including the CSA, changing the selected channel used in the Repeater AP Beacon step and the Repeater AP Communication step from the first channel to the second channel.

[0041] According to the above wireless communication method, when any one of the one or more repeater access points detects a radar wave using the frequency of the selected channel, the repeater access point transmits an RCSA toward the root access point.

[0042] Then, when the root access point receives the RCSA, it uses the first channel to transmit a beacon including a CSA indicating that the selected channel will be changed from the first channel to the second channel, and changes the selected channel from the first channel to the second channel.

[0043] Then, one or more repeater access points change the selected channel from the first channel to the second channel after receiving the beacon that includes the CSA.

[0044] In this way, according to the above wireless communication method, a communication system is realized in which, when radar waves using the frequency band of a channel in use are detected in a WDS using a specified band, the access points constituting the WDS can change the channel being used to another channel without switching modes.

[0045] A program according to an embodiment of the present disclosure is a program for causing a root access point in a wireless communication system including a root access point located at the highest position in a WDS using a predetermined band and one or more repeater access points located below the root access point in the WDS to execute root access point processing, the root access point processing including a root AP communication step of alternatively selecting one channel of a plurality of channels in the predetermined band as a channel to be used for communication in the WDS and communicating with at least one of the one or more repeater access points using the selected selected channel, a root AP beacon step of transmitting a beacon using the selected channel, and a root AP radar wave detection step of detecting radar waves using a frequency band of the selected channel, and when a first channel of the plurality of channels is selected as the selected channel in the root AP communication step, a reverse channel switch (RCSA) signal indicating that a radar wave using the frequency band of the selected channel has been detected in the root AP radar wave detection step or that one of the one or more repeater access points has detected a radar wave using the frequency band of the selected channel is output. When a CSA (Channel Switch Announcement) is received, a second channel different from the first channel is selected from among the plurality of channels as a new selected channel in the WDS, and in the Root AP Beacon step, the beacon including a CSA (Channel Switch Announcement) indicating that the channel to be used for communication in the WDS will be changed from the first channel to the second channel is transmitted using the first channel, and then the selected channel to be used in the Root AP Beacon step is changed from the first channel to the second channel, and at the same time, the selected channel to be used in the Root AP Communication step is changed from the first channel to the second channel.

[0046] According to the above program, when a root access point in a WDS using a specified band that executes the above program receives an RCSA, it transmits a beacon including a CSA indicating that the selected channel will be changed from the first channel to the second channel, and also changes the selected channel from the first channel to the second channel.

[0047] In this way, according to the above program, an access point is realized which is a root access point in a WDS using a specified band, and which can change the channel being used to another channel without switching modes when radar waves using the frequency band of a channel being used in the WDS are detected.

[0048] A program according to an embodiment of the present disclosure is a program for causing each of one or more repeater access points in a wireless communication system, the program including a root access point located at the highest position in a WDS using a predetermined band, and one or more repeater access points located below the root access point in the WDS, to execute repeater access point processing, the repeater access point processing including performing a repeater access point process on the root access point and / or the one or more repeater access points using a selected channel, which is one channel among a plurality of channels in the predetermined band alternatively selected by the root access point, as a channel to be used for communication in the WDS. The repeater AP communication step includes a repeater AP communication step of communicating with at least one of the other repeater access points among the repeater APs, a repeater AP radar wave detection step of detecting radar waves using the frequency band of the selected channel, and a repeater AP beacon step of receiving a beacon transmitted from the root access point using the selected channel or transmitting and receiving a beacon with another repeater access point, and in the repeater AP communication step, when the radar wave is detected in the repeater AP radar wave detection step, or in the repeater AP communication step, a RCSA (Reverse Cross-Signal Acquisition) signal indicating that one of the one or more repeater access points has detected the radar wave is output. When a repeater AP beacon step receives a Channel Switch Announcement (CSA), the repeater AP transmits the RCSA to the root access point located one level higher in the WDS or to an upper repeater access point located one level higher in the WDS among the one or more repeater access points, and transmits a CSA (Channel Switch Announcement) indicating that the channel to be used for communication in the WDS, which is received from the root access point or an upper repeater access point located one level higher in the WDS among the one or more repeater access points, from a first channel among the multiple channels to a second channel among the multiple channels that is different from the first channel.When the repeater AP receives a beacon including a CSA (Continued State Announcement), after transmitting the beacon including the CSA, the selected channel used in the repeater AP beacon step and the repeater AP communication step is changed from the first channel to the second channel.

[0049] According to the above program, each of one or more repeater access points in a WDS using a specified band that executes the above program transmits an RCSA toward the root access point when it detects radar waves using the frequency band of the selected channel or when it receives an RCSA.

[0050] Then, each of the one or more repeater access points changes the selected channel from the first channel to the second channel after receiving the beacon including the CSA.

[0051] In this way, according to the above program, an access point is realized which is one or more repeater access points in a WDS using a specified band, and which can change the channel being used to another channel without switching modes when radar waves using the frequency band of a channel in use are detected. Effect of the Invention

[0052] According to a wireless communication system etc. relating to one embodiment of the present disclosure, in a WDS using a predetermined band, when radar waves using the frequency band of a channel in use are detected, a communication system is realized in which the access points constituting the WDS can change the channel being used to another channel without switching modes. [Brief description of the drawings]

[0053] [Figure 1] FIG. 1 is a block diagram showing a configuration of a wireless communication system according to an embodiment. [Figure 2A]FIG. 2A is a block diagram illustrating a functional configuration of a root access point according to an embodiment. [Figure 2B] FIG. 2B is a block diagram illustrating a functional configuration of a repeater access point according to an embodiment. [Diagram 3] FIG. 3 is a schematic diagram showing how a root access point according to the embodiment transmits a beacon including a CSA. [Figure 4] FIG. 4 is a schematic diagram showing how a repeater access point according to the embodiment transmits an RCSA. [Diagram 5] FIG. 5 is a schematic diagram showing how a repeater access point according to the embodiment transmits a beacon including a CSA. [Figure 6A] FIG. 6A is a schematic diagram showing how a beacon including a CSA is transmitted within a wireless communication system according to an embodiment. [Figure 6B] FIG. 6B is a schematic diagram showing how beacons including RCSA and CSA are transmitted within the wireless communication system according to the embodiment. [Figure 7] FIG. 7 is a flowchart of a root access point process performed by a root access point according to the embodiment. [Figure 8] FIG. 8 is a flowchart of a repeater access point process performed by the repeater access point according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] (How one aspect of the present disclosure was achieved) As mentioned above, Japan's Radio Law requires that in a WDS using the DFS band, if radar waves are detected using the frequency band of a channel currently in use, the channel in use must be changed to another channel.

[0055] This channel change must be done within 10 seconds of detecting the radar wave.

[0056] On the other hand, Japan's Radio Law allows a maximum of 260 msec of communication in total using the previous channel during the period from when radar waves are detected until the channel is changed.

[0057] The inventors thought that if they used a maximum of 260 msec of communication in total using the channel before the change, it might be possible for the access points that make up the WDS to change the channel they were using to another channel without switching modes.

[0058] Based on this idea, the inventors have conducted repeated experiments and studies, and as a result, have arrived at a wireless communication system and the like according to one aspect of the present disclosure.

[0059] Hereinafter, a specific example of a wireless communication system according to an embodiment of the present disclosure will be described with reference to the drawings. Each embodiment shown here shows a specific example of the present disclosure. Therefore, the numerical values, shapes, components, arrangement and connection of the components, steps (processes) and the order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, each figure is a schematic diagram and is not necessarily an exact illustration. In each figure, the same reference numerals are given to substantially the same configurations, and duplicated explanations are omitted or simplified.

[0060] (Embodiment) <Configuration> FIG. 1 is a block diagram showing a configuration of a wireless communication system 1 according to an embodiment.

[0061] As shown in Fig. 1, a wireless communication system 1 includes a root access point 10 and one or more repeater access points 20. Here, the one or more repeater access points 20 correspond to the repeater access points 20A to 20E in Fig. 1. In this specification, when it is not necessary to explicitly distinguish between the repeater access points 20A to 20E, the repeater access points 20A to 20E will be simply referred to as the repeater access points 20.

[0062] The wireless communication system 1 realizes a wireless distribution system (WDS) that uses a predetermined band. Wireless communication in a WDS is a known technique, and detailed description thereof will be omitted.

[0063] Here, the predetermined band is described as a DFS (Dynamic Frequency Selection) band in the wireless LAN (Local Area Network) standardized by IEEE (Institute of Electrical and Electronic Engineers) 802.11 as an example that does not necessarily need to be limited. The DFS band here includes channels 36, 40, 44, and 48 of the W53 band in the 5 GHz band, and channels 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, and 144 of the W56 band in the 5 GHz band.

[0064] The root access point 10 is an access point located at the highest level in the WDS realized by the wireless communication system 1.

[0065] The repeater access point 20 is an access point located below the root access point 10 in the WDS realized by the wireless communication system 1.

[0066] The root access point 10 and the repeater access point 20 may be access points having the same hardware configuration equipped with a setting interface represented by, for example, a DIP switch, and may function as the root access point 10 by being set in the setting interface to function as the root access point 10, and may function as the repeater access point 20 by being set in the setting interface to function as the repeater access point 20. In addition, the root access point 10 and the repeater access point 20 may have their respective functions (route, repeat) set on a setting tool (software) provided in the access point that performs, for example, initial settings for wireless communication.

[0067] FIG. 2A is a block diagram showing the functional configuration of the root access point 10, and FIG. 2B is a block diagram showing the functional configuration of the repeater access point 20. As shown in FIG.

[0068] As shown in FIG. 2A, the root access point 10 includes a root AP communication unit 11, a root AP beacon unit 12, and a root AP radar wave detection unit 13, and as shown in FIG. 2B, the repeater access point 20 includes a repeater AP communication unit 21, a repeater AP beacon unit 22, and a repeater AP radar wave detection unit 23.

[0069] The root AP communication unit 11 alternatively selects one channel from among multiple channels in a specified band as a channel to be used for communication in the WDS, notifies the root AP beacon unit 12 of the channel, and uses the selected channel to communicate with at least one of the one or more repeater access points 20.

[0070] More specifically, as shown in FIG. 1, the root AP communication unit 11 communicates with a repeater access point 20A and a repeater access point 20D that are positioned immediately below the root access point 10 in the WDS.

[0071] Returning again to FIG. 2A and FIG. 2B, the description of the wireless communication system 1 will continue.

[0072] The root AP beacon unit 12 receives a notification of the channel selected (chosen and determined) by the root AP communication unit 11, and transmits a beacon including a CSA (Channel Switch Announcement) including the selected channel.

[0073] When route AP radar wave detection unit 13 detects radar waves using the frequency band of the selected channel, it notifies route AP communication unit 11 of the detection.

[0074] The repeater AP communication unit 21 extracts a selected channel included in the CSA from a beacon including the CSA transmitted by the root AP beacon unit 12 and received by the repeater AP beacon unit 22, notifies the repeater AP beacon unit 22 of the selected channel, and uses this selected channel to communicate with the root access point 10 and / or at least one of the other repeater access points among the one or more repeater access points 20.

[0075] More specifically, as shown in FIG. 1, the repeater AP communication unit 21 provided in the repeater access point 20A communicates with the root access point 10, which is located one level above the repeater access point 20A in the WDS, and with the repeater access point 20B, which is located one level below the repeater access point 20A in the WDS.

[0076] Furthermore, the repeater AP communication unit 21 included in the repeater access point 20B communicates with the repeater access point 20A located immediately above the repeater access point 20B in the WDS, and with the repeater access point 20C located immediately below the repeater access point 20B in the WDS.

[0077] Furthermore, the repeater AP communication unit 21 included in the repeater access point 20C communicates with the repeater access point 20B that is located one level above the repeater access point 20C in the WDS.

[0078] Furthermore, the repeater AP communication unit 21 included in the repeater access point 20D communicates with the root access point 10 located immediately above the repeater access point 20D in the WDS, and with the repeater access point 20E located immediately below the repeater access point 20D in the WDS.

[0079] Furthermore, the repeater AP communication unit 21 included in the repeater access point 20E communicates with the repeater access point 20D that is located one level above the repeater access point 20E in the WDS.

[0080] Returning again to FIG. 2A and FIG. 2B, the description of the wireless communication system 1 will continue.

[0081] The repeater AP beacon unit 22 receives a notification of the selected channel from the repeater AP communication unit 21, and uses this to transmit and receive beacons.

[0082] Repeater AP radar wave detection unit 23 detects radar waves using the frequency band of the selected channel and notifies repeater AP communication unit 21 of the detection.

[0083] In the wireless communication system 1 having the above configuration, when the repeater AP radar wave detection unit 23 detects radar waves, or when the repeater AP communication unit 21 receives an RCSA (Reverse Channel Switch Announcement) from a lower repeater access point located one level lower in the WDS than the repeater access point 20 having the repeater AP communication unit 21, indicating that one of the one or more repeater access points 20 has detected radar waves, the repeater AP communication unit 21 transmits the RCSA to the root access point 10 located one level higher in the WDS than the repeater access point 20 having the repeater AP communication unit 21, or to the repeater access point 20 located one level higher.

[0084] In the wireless communication system 1 having the above configuration, when the root AP communication unit 11 selects the first channel of the above multiple channels as the selected channel, when the root AP radar wave detection unit 13 receives a notification that it has detected a radar wave, or when the root AP communication unit 11 receives an RCSA from the lower repeater AP communication unit 21, the root AP communication unit 11 selects a channel different from the first channel as the second channel of the above multiple channels and notifies the root AP beacon unit 12 of this. The root AP beacon unit 12 transmits a beacon including a CSA indicating that the channel used for communication is changed from the first channel to the second channel, and then changes the selected channel used for transmitting and receiving the beacon from the first channel to the second channel. At the same time, the root AP communication unit 11 changes the selected channel used for the communication selected by itself from the first channel to the second channel.

[0085] In the wireless communication system 1 having the above configuration, when the repeater AP beacon unit 22 receives a beacon including a CSA, it transmits the beacon including the CSA and then changes the selected channel used for the beacon from the first channel to the second channel according to the contents of the CSA. At the same time, the repeater AP communication unit 21 also changes the selected channel used for communication from the first channel to the second channel.

[0086] In addition, when the repeater AP beacon unit 22 does not receive a beacon including a CSA within a specified period of time despite the repeater AP communication unit 21 transmitting an RCSA due to the repeater AP radar wave detection unit 23 detecting radar waves, the repeater AP communication unit 21 may suppress communication using the selected channel and search for a channel used for communication in the WDS.

[0087] In addition, the repeater AP beacon unit 22 may suppress the transmission of a beacon using a selected channel when the repeater AP radar wave detection unit 23 detects radar waves and the repeater AP communication unit 21 transmits an RCSA but the repeater AP beacon unit 22 does not receive a beacon including a CSA within a specified period of time.

[0088] On the other hand, when an RCSA is received from another repeater access point 20, and the repeater AP communication unit 21 transmits an RCSA as a result, but the repeater AP beacon unit 22 does not receive a beacon including a CSA within a predetermined period of time, the repeater access point 20 maintains communication on the channel (original channel) used for communication in the WDS. That is, the repeater access point 20 having the repeater AP beacon unit 22 does not detect radar waves with the repeater AP radar wave detection unit 23, and therefore can maintain communication on the original channel.

[0089] In the end, when the root AP communication unit 11 selects the first channel as the selected channel, if the repeater AP beacon unit 22 receives a beacon including a CSA (contents changing the channel for transmitting and receiving beacons / communications to the second channel), the repeater AP beacon unit 22 transmits a beacon including a CSA using the first channel, and then changes the selected channel used for transmitting and receiving beacons from the first channel to the second channel. At the same time, the repeater AP communication unit 21 also changes the selected channel used for communication from the first channel to the second channel.

[0090] In addition, when the root AP communication unit 11 changes the selected channel to be used for communication from a first channel to a second channel, the root AP communication unit 11 may suppress communication using the second channel until a CAC (Channel Availability Check) period has elapsed (e.g., 60 seconds) from the time of the change.

[0091] In addition, when the root AP beacon unit 12 changes the selected channel used for transmitting a beacon from a first channel to a second channel, the root AP beacon unit 12 may suppress transmission of the beacon using the second channel until the CAC period has elapsed from the time of the change.

[0092] In addition, when the repeater AP communication unit 21 changes the selected channel to be used for communication from a first channel to a second channel, the repeater AP communication unit 21 may suppress communication using the second channel until the CAC period has elapsed from the time of the change.

[0093] In addition, when the repeater AP beacon unit 22 changes the selected channel used for transmitting a beacon from a first channel to a second channel, the repeater AP beacon unit 22 may suppress transmission of the beacon using the second channel until the CAC period has elapsed from the time of the change.

[0094] Furthermore, when transmitting a beacon including a CSA, the root AP beacon unit 12 may transmit the beacon multiple times (for example, twice) in succession at a first predetermined interval (for example, 100 msec).

[0095] Furthermore, when transmitting a beacon including a CSA, the repeater AP beacon unit 22 may transmit the beacon multiple times (for example, twice) in succession at a first predetermined interval (for example, 100 msec).

[0096] Furthermore, when transmitting an RCSA, the repeater AP communication unit 21 may transmit the RCSA multiple times (for example, five times) consecutively at a second predetermined interval (for example, 200 msec).

[0097] In addition, after transmitting a beacon including a CSA, if the root AP radar wave detection unit 13 detects radar waves and if the root AP communication unit 11 receives an RCSA, the root AP beacon unit 12 may suppress further transmission of the beacon including the CSA.

[0098] In addition, after transmitting the RCSA, if the repeater AP radar wave detection unit 23 detects radar waves and if the repeater AP communication unit 21 receives the RCSA, the repeater AP communication unit 21 may suppress further transmission of the RCSA.

[0099] FIG. 3 is a schematic diagram showing how the root access point 10 transmits a beacon including a CSA.

[0100] As shown in FIG. 3, the root access point 10 (1) detects radar waves using the frequency band of the selected channel, or (2) receives an RCSA, and (3) transmits a beacon including a CSA.

[0101] At this time, the root access point 10 may, for example, transmit the beacon multiple times (for example, twice) in succession at a first predetermined interval (for example, 100 msec), or, for example, after transmitting a beacon including a CSA, if it detects radar waves using the frequency band of the selected channel and if it further receives an RCSA, it may suppress further transmission of the beacon including a CSA.

[0102] FIG. 4 is a schematic diagram showing how the repeater access point 20 transmits an RCSA.

[0103] As shown in FIG. 4, when the repeater access point 20 (1) detects radar waves using the frequency band of the selected channel, or (2) receives an RCSA from a repeater access point 20 located one level lower in the WDS, (3) it transmits the RCSA to a higher-level device (root access point 10 or repeater access point 20) located one level higher in the WDS.

[0104] At this time, the repeater access point 20 may, for example, transmit the RCSA multiple times (for example, five times) in succession at a second predetermined interval (for example, 200 msec), or may, for example, after transmitting the RCSA, if it further detects radar waves using the frequency band of the selected channel and if it further receives an RCSA, suppress further transmission of the RCSA.

[0105] FIG. 5 is a schematic diagram showing how the repeater access point 20 transmits a beacon including a CSA.

[0106] As shown in FIG. 5, when the repeater access point 20 (1) receives a beacon including a CSA from a higher-level device, (2) it transmits a beacon including a CSA.

[0107] At this time, the repeater access point 20 may transmit the beacon multiple times (for example, twice) in succession at a first predetermined interval (for example, 100 msec).

[0108] Figure 6A is a schematic diagram showing how a beacon including a CSA is transmitted within the wireless communication system 1 when the root access point 10 detects radar waves using the frequency band of the selected channel, and Figure 6B is a schematic diagram showing how a beacon including an RCSA and a CSA is transmitted within the wireless communication system 1 when the repeater access point 20B detects radar waves using the frequency band of the selected channel.

[0109] As shown in FIGS. 6A and 6B, the RCSA is transmitted from the subordinate repeater access point 20 in the WDS to the root access point 10, and the CSA is transmitted from the root access point 10 to the subordinate repeater access point 20.

[0110] <Operation> The operation of the wireless communication system 1 having the above configuration will be described below.

[0111] FIG. 7 is a flowchart of the root access point process performed by the root access point 10. As shown in FIG.

[0112] The root access point process is started, for example, when the root access point 10 is started.

[0113] When the root access point process is started, the root AP communication unit 11 checks whether or not the root AP radar wave detection unit 13 has received a notification that it has detected a radar wave that uses the frequency band of the selected channel (step S10).

[0114] In the processing of step S10, if radar waves using the frequency band of the selected channel are not detected (step S10: No), the root AP communication unit 11 checks whether or not an RCSA has been received from the repeater access point 20 (step S20).

[0115] In the process of step S20, if RCSA has not been received (step S20: No), the process proceeds to step S10 again.

[0116] In the process of step S10, if a radar wave using the frequency band of the selected channel is detected (step S10: Yes), or in the process of step S20, if an RCSA is received (step S20: Yes), the root AP communication unit 11 selects a new channel different from the currently selected channel (step S25) and notifies the root AP beacon unit 12 of this (step S25). The root AP beacon unit 12 transmits a beacon including a CSA indicating a change to the new selected channel multiple times at a first predetermined interval (step S30), and then changes the selected channel used for the transmission and reception of the beacon and communication from the current channel to the new channel selected in step S25 (hereinafter also referred to as the "changed channel") (step S40).

[0117] When the root AP beacon unit 12 changes the selected channel used for transmitting and receiving beacons to the changed channel, the root AP beacon unit 12 suppresses the transmission of beacons using the changed channel until the CAC period has elapsed from the time of the change (step S50: No is repeated until the CAC period has elapsed, and then step S50: Yes). At this time, the root AP communication unit 11 also suppresses communication using the changed channel until the CAC period has elapsed from the time of the change.

[0118] In the process of step S50, if the CAC period has elapsed (step S50: Yes), the process proceeds to step S10 again.

[0119] FIG. 8 is a flowchart of the repeater access point process performed by the repeater access point 20. As shown in FIG.

[0120] The repeater access point process is started, for example, when the repeater access point 20 is started.

[0121] When the repeater access point process is started, the repeater AP communication unit 21 checks whether the repeater AP radar wave detection unit 23 has detected a radar wave that uses the frequency band of the selected channel (step S110).

[0122] In the processing of step S110, if radar waves using the frequency band of the selected channel have not been detected (step S110: No), the repeater AP communication unit 21 checks whether or not an RCSA has been received from another repeater access point 20 (step S120).

[0123] In the process of step S120, if the RCSA has not been received (step S120: No), the process proceeds to step S110 again.

[0124] If radar waves using the frequency band of the selected channel are detected in the processing of step S110 (step S110: Yes), or if an RCSA is received in the processing of step S120 (step S120: Yes), the repeater AP communication unit 21 transmits the RCSA multiple times in succession at a second predetermined interval to the root access point 10 located one level above the repeater access point 20, or to the repeater access point 20 located one level above (step S130).

[0125] If the repeater AP beacon unit 22 receives a beacon including a CSA from a higher-level device within a specified period after the RCSA has been transmitted multiple times, or during multiple transmissions (step S140: Yes), the repeater AP beacon unit 22 transmits the beacon including the CSA multiple times in succession at a first specified interval (step S150), and then the repeater AP beacon unit 22 and the repeater AP communication unit 21 change the selected channel used for transmitting and receiving the beacon and for communication from the current channel to a changed channel, which is another channel among the multiple channels in the specified band specified by the CSA (step S160).

[0126] When the repeater AP beacon unit 22 and the repeater AP communication unit 21 change the selected channel used for beacons and communication to the changed channel, they suppress the transmission of beacons and communication using the changed channel until the CAC period has elapsed from the time of the change (step S170: No is repeated until the CAC period has elapsed, and then step S170: Yes).

[0127] If the repeater AP beacon unit 22 does not receive a beacon including a CSA within a specified period after the RCSA has been transmitted multiple times (step S140: No), the repeater AP communication unit 21 checks in the processing of step S110 whether the repeater AP radar wave detection unit 23 has detected radar waves using the frequency band of the selected channel and therefore proceeds to the processing of step S130 (step S180).

[0128] In the processing of step S180, if the repeater AP radar wave detection unit 23 has detected radar waves using the frequency band of the selected channel and therefore proceeds to processing of step S130 (step S180: Yes), the repeater AP communication unit 21 suppresses communication using the selected channel, and the repeater AP beacon unit 22 suppresses transmission of beacons using the selected channel (step S190).

[0129] In the processing of step S180, if the repeater AP radar wave detection unit 23 has not detected radar waves using the frequency band of the selected channel but has received RCSA from a lower repeater access point (Yes in step S130), and therefore has proceeded to processing of step S130 (step S180: No), processing of step S190 is not performed and processing proceeds to processing of step S200.

[0130] If communication using the selected channel is suppressed in the process of step S190, or if the process of step S180 proceeds to No, the repeater AP communication unit 21 starts searching for a channel to be used for communication in the WDS (step S200).

[0131] In the process of step S170, if the CAC period has elapsed (step S170: Yes), and if the process of step S200 has ended, the process proceeds again to the process of step S110.

[0132] <Consideration> According to the wireless communication system 1 having the above-described configuration, when any of the one or more repeater access points 20 detects radar waves using the frequency of the selected channel (first channel), that repeater access point 20 transmits an RCSA toward the root access point 10.

[0133] Then, when the root access point 10 receives the RCSA, it uses the first channel to transmit a beacon including a CSA indicating that the selected channel will be changed from the first channel to the second channel, and changes the selected channel from the first channel to the second channel.

[0134] Then, when one or more repeater access points 20 receive a beacon including the CSA, they transmit a beacon including the CSA to the subordinate repeater access points 20 and then change the selected channel from the first channel to the second channel.

[0135] In this way, according to the wireless communication system 1 having the above configuration, when radar waves using the frequency band of a channel in use are detected in a WDS using a specified band, a communication system is realized in which the access points constituting the WDS can change the channel being used to another channel without switching modes.

[0136] (supplement) As described above, the present disclosure has been described based on the embodiments as examples of the technology disclosed in the present application. However, the present disclosure is not limited to the embodiments. As long as it does not deviate from the gist of the present disclosure, various modifications conceived by a person skilled in the art to the present embodiment, or forms constructed by combining components in the embodiments or modifications, may also be included within the scope of one or more aspects of the present disclosure.

[0137] A comprehensive or specific aspect of the present disclosure may be realized in a system, an apparatus, a method, an integrated circuit, a program, or a non-transitory recording medium such as a computer-readable CD-ROM. Also, the present disclosure may be realized in any combination of a system, an apparatus, a method, an integrated circuit, a program, and a non-transitory recording medium. For example, the present disclosure may be realized as a program that causes a computer device or the like to execute the process performed by the root access point 10 or the process performed by the repeater access point 20. [Industrial Applicability]

[0138] The present disclosure is widely applicable to wireless communication systems and the like. [Explanation of symbols]

[0139] 1. Wireless communication systems 10. Root Access Points 11 Route AP News Department 12 Root AP Beacon Section 13 Route AP radar wave detection unit 20, 20A, 20B, 20C, 20D, 20E Repeater Access Points 21 Repeater AP Communications Division 22 Repeater AP beacon section 23 Repeater AP radar wave detection unit

Claims

1. A wireless communication system comprising: a root access point located at the highest level in a wireless distribution system (WDS) using a predetermined band; and one or more repeater access points located below the root access point in the WDS, The root access point is a root AP communication unit that alternatively selects one channel from among a plurality of channels in the predetermined band as a channel to be used for communication in the WDS, and communicates with at least one repeater access point from among the one or more repeater access points using the selected channel; a root AP beacon unit that transmits a beacon using the selected channel; a route AP radar wave detection unit that detects radar waves using the frequency band of the selected channel; Each of the one or more repeater access points: a repeater AP communication unit that communicates with the root access point and / or at least one of the other repeater access points among the one or more repeater access points using the selected channel; a repeater AP radar wave detection unit for detecting radar waves using the frequency band of the selected channel; a repeater AP beacon unit that transmits and receives the beacon, when the repeater AP radar wave detection unit detects the radar wave, or when the repeater AP communication unit receives a Reverse Channel Switch Announcement (RCSA) indicating that one of the one or more repeater access points has detected the radar wave from a lower repeater access point that is located one level lower in the WDS among the one or more repeater access points, the repeater AP communication unit transmits the RCSA to the root access point that is located one level higher in the WDS, or to a higher repeater access point that is located one level higher in the WDS among the one or more repeater access points; When the root AP communication unit selects a first channel of the plurality of channels as the selected channel, when the root AP radar wave detection unit detects the radar wave or receives the RCSA, The root AP communication unit selects a second channel different from the first channel among the plurality of channels as a new selected channel in the WDS, The root AP beacon unit transmits the beacon using the first channel, the beacon including a CSA (Channel Switch Announcement) indicating that a channel used for communication in the WDS is to be changed from the first channel to the second channel; Thereafter, the selected channel used for transmitting the beacon is changed from the first channel to the second channel, and at the same time, the root AP communication unit changes the selected channel used for communication from the first channel to the second channel; When the repeater AP beacon unit receives the beacon including the CSA, the repeater AP communication unit changes the selected channel used for communication from the first channel to the second channel after transmitting the beacon including the CSA. Wireless communication system.

2. When the repeater AP beacon unit does not receive the beacon including the CSA within a predetermined period of time despite the repeater AP communication unit transmitting the RCSA due to the repeater AP radar wave detection unit detecting the radar wave, the repeater AP communication unit suppresses communication using the selected channel and searches for a channel used for communication in the WDS.

2. The wireless communication system according to claim 1.

3. when the repeater AP beacon unit receives the beacon including the CSA in a case where the root AP communication unit selects the first channel as the selected channel, the repeater AP beacon unit transmits the beacon including the CSA using the first channel, and then changes the selected channel used for transmitting and receiving the beacon from the first channel to the second channel; when the root AP communication unit changes the selected channel used for communication from the first channel to the second channel, the root AP communication unit suppresses communication using the second channel until a CAC (Channel Availability Check) period has elapsed from the time of the change; When the root AP beacon unit changes the selected channel used for transmitting the beacon from the first channel to the second channel, the root AP beacon unit suppresses transmission of the beacon using the second channel until the CAC period has elapsed from the time of the change, when the repeater AP communication unit changes the selected channel used for communication from the first channel to the second channel, the repeater AP communication unit suppresses communication using the second channel until the CAC period has elapsed from the time of the change, When the repeater AP beacon unit changes the selected channel used for transmitting the beacon from the first channel to the second channel, the repeater AP beacon unit suppresses transmission of the beacon using the second channel until the CAC period has elapsed from the time of the change.

3. The wireless communication system according to claim 1 or 2.

4. When transmitting the beacon including the CSA, the root AP beacon unit transmits the beacon multiple times in succession at a first predetermined interval; when transmitting the beacon including the CSA, the repeater AP beacon unit transmits the beacon multiple times consecutively at the first predetermined interval; When transmitting the RCSA, the repeater AP communication unit transmits the RCSA multiple times in succession at a second predetermined interval.

3. The wireless communication system according to claim 1 or 2.

5. the root AP beacon unit, after transmitting the beacon including the CSA, when the root AP communication unit receives the RCSA, suppresses further transmission of the beacon including the CSA; After transmitting the RCSA, if the repeater AP radar wave detection unit detects the radar wave and if the repeater AP communication unit receives the RCSA, the repeater AP communication unit suppresses further transmission of the RCSA.

3. The wireless communication system according to claim 1 or 2.

6. The predetermined band is a band included in the DFS (Dynamic Frequency Selection) band.

3. The wireless communication system according to claim 1 or 2.

7. A root access point in a wireless communication system including a WDS using a predetermined band and one or more repeater access points located below the root access point in the WDS, a root AP communication unit that alternatively selects one channel from among a plurality of channels in the predetermined band as a channel to be used for communication in the WDS, and communicates with at least one repeater access point from among the one or more repeater access points using the selected channel; a root AP beacon unit that transmits a beacon using the selected channel; a route AP radar wave detection unit that detects radar waves using the selected channel; When the root AP communication unit selects a first channel among the plurality of channels as the selected channel, When the root AP radar wave detection unit detects the radar wave, or when the root AP communication unit receives a Reverse Channel Switch Announcement (RCSA) indicating that one of the one or more repeater access points has detected the radar wave, The root AP communication unit selects a second channel different from the first channel among the plurality of channels as a new selected channel in the WDS, The root AP beacon unit transmits the beacon using the first channel, the beacon including a CSA (Channel Switch Announcement) indicating that a channel used for communication in the WDS is to be changed from the first channel to a second channel different from the first channel among the plurality of channels; Thereafter, the selected channel used for transmitting the beacon is changed from the first channel to the second channel, and at the same time, the root AP communication unit changes the selected channel used for communication from the first channel to the second channel. Access point.

8. A wireless communication system including a root access point located at the highest level in a WDS using a predetermined band, and one or more repeater access points located below the root access point in the WDS, each of the one or more repeater access points comprising: a repeater AP communication unit that communicates with the root access point and / or at least one of the other repeater access points among the one or more repeater access points, using a selected channel that is one channel of a plurality of channels in the predetermined band alternatively selected by the root access point as a channel to be used for communication in the WDS; a repeater AP radar wave detection unit for detecting radar waves using the frequency band of the selected channel; a repeater AP beacon unit that receives a beacon transmitted using the selected channel; When the root access point selects a first channel as the selected channel, if the repeater AP radar wave detection unit detects the radar wave, or if the repeater AP communication unit receives an RCSA (Reverse Channel Switch Announcement) from a lower repeater access point that is one level lower in the WDS among the one or more repeater access points, indicating that one of the one or more repeater access points has detected the radar wave, the repeater AP communication unit transmits an RCSA indicating that the radar wave has been detected to the root access point that is one level higher in the WDS or to a higher repeater access point that is one level higher in the WDS among the one or more repeater access points; When the repeater AP beacon unit receives the beacon including a CSA (Channel Switch Announcement) indicating that the channel used for communication in the WDS is to be changed from the first channel to a second channel different from the first channel among the multiple channels, the repeater AP beacon unit transmits the beacon including the CSA using the first channel, and then the repeater AP communication unit changes the selected channel used for communication from the first channel to the second channel. Access point.

9. When the repeater AP beacon unit does not receive the beacon including the CSA within a predetermined period of time despite the repeater AP communication unit transmitting the RCSA due to the repeater AP radar wave detection unit detecting the radar wave, the repeater AP communication unit suppresses communication using the selected channel and searches for a channel used for communication in the WDS.

9. The access point of claim 8.

10. when the repeater AP communication unit changes the selected channel used for communication from the first channel to the second channel, the repeater AP communication unit suppresses communication using the second channel until a CAC period has elapsed from a time of the change; When the repeater AP beacon unit changes the selected channel used for transmitting the beacon from the first channel to the second channel, the repeater AP beacon unit suppresses transmission of the beacon using the second channel until the CAC period has elapsed from the time of the change. An access point according to claim 8 or claim 9.

11. the repeater AP beacon unit transmits the beacon including the CSA multiple times in succession at a first predetermined interval; When transmitting the RCSA, the repeater AP communication unit transmits the RCSA multiple times in succession at a second predetermined interval. An access point according to claim 8 or claim 9.

12. After transmitting the RCSA, if the repeater AP radar wave detection unit detects the radar wave and if the repeater AP communication unit receives the RCSA, the repeater AP communication unit suppresses further transmission of the RCSA. An access point according to claim 8 or claim 9.

13. The predetermined band is a band included in the DFS band. An access point according to claim 8 or claim 9.

14. A wireless communication method performed by a wireless communication system including a root access point located at the highest level in a WDS using a predetermined band, and one or more repeater access points located below the root access point in the WDS, comprising: The root access point performs a root AP communication step of alternatively selecting one channel from among a plurality of channels in the predetermined band as a channel to be used for communication in the WDS, and using the selected channel to communicate with at least one repeater access point from among the one or more repeater access points; a root AP beacon step of transmitting a beacon using the selected channel; a root AP radar wave detection step of detecting a radar wave using the frequency band of the selected channel; each of the one or more repeater access points performs a repeater AP communication step of communicating with the root access point and / or at least one of other repeater access points among the one or more repeater access points using the selected channel; a repeater AP radar wave detection step of detecting a radar wave using the frequency band of the selected channel; A repeater AP beacon step of transmitting and receiving the beacon, in the repeater AP communication step, when the radar wave is detected in the repeater AP radar wave detection step, or when a reverse channel switch announcement (RCSA) indicating that one of the one or more repeater access points has detected the radar wave is received from a lower repeater access point located one level lower in the WDS among the one or more repeater access points in the repeater AP communication step, the RCSA is transmitted to the root access point located one level higher in the WDS, or to a higher repeater access point located one level higher in the WDS among the one or more repeater access points; In the case where a first channel of the plurality of channels is selected as the selected channel in the route AP communication step, when a wave is detected in the route AP radar wave detection step or when the RCSA is received, a second channel different from the first channel is selected as a new selected channel in the WDS; In the root AP beacon step, the beacon includes a CSA (Channel Switch Announcement) indicating that a channel used for communication in the WDS is to be changed from the first channel to a second channel, using the first channel; Then, the selected channel used in the root AP beacon step is changed from the first channel to the second channel, and at the same time, the selected channel used in the root AP communication step is changed from the first channel to the second channel; In the repeater AP communication step, when the beacon including the CSA is received in the repeater AP beacon step, the selected channel used in the repeater AP beacon step and the repeater AP communication step is changed from the first channel to the second channel after transmitting the beacon including the CSA. A wireless communication method.

15. A program for causing a root access point to execute a root access point process in a wireless communication system including a root access point located at the highest level in a WDS using a predetermined band and one or more repeater access points located below the root access point in the WDS, the program comprising: The root access point process includes: a root AP communication step of alternatively selecting one channel from among a plurality of channels in the predetermined band as a channel to be used for communication in the WDS, and using the selected channel to communicate with at least one repeater access point from among the one or more repeater access points; a root AP beacon step of transmitting a beacon using the selected channel; a root AP radar wave detection step of detecting a radar wave using the frequency band of the selected channel; Including, In the root AP communication step, when a first channel of the plurality of channels is selected as the selected channel, when a Reverse Channel Switch Announcement (RCSA) indicating that a radar wave using a frequency band of the selected channel has been detected in the root AP radar wave detection step or that one of the one or more repeater access points has detected a radar wave, the second channel of the plurality of channels being different from the first channel is selected as a new selected channel in the WDS; In the root AP beacon step, the beacon includes a CSA (Channel Switch Announcement) indicating that a channel used for communication in the WDS is to be changed from the first channel to the second channel, using the first channel; Thereafter, the selected channel used in the root AP beacon step is changed from the first channel to the second channel, and at the same time, the selected channel used in the root AP communication step is changed from the first channel to the second channel. program.

16. A program for causing each of one or more repeater access points in a wireless communication system, the program comprising: a root access point located at the highest level in a WDS using a predetermined band; and one or more repeater access points located below the root access point in the WDS, the program causing each of the one or more repeater access points to execute a repeater access point process, the program comprising: The repeater access point process includes: a repeater AP communication step of communicating with the root access point and / or at least one of the other repeater access points among the one or more repeater access points by using a selected channel, which is one channel of a plurality of channels in the predetermined band alternatively selected by the root access point as a channel to be used for communication in the WDS; a repeater AP radar wave detection step of detecting a radar wave using the frequency band of the selected channel; A repeater AP beacon step of receiving a beacon transmitted from the root access point using the selected channel, or transmitting and receiving a beacon between the root access point and another repeater access point; In the repeater AP communication step, when the radar wave is detected in the repeater AP radar wave detection step, or when a Reverse Channel Switch Announcement (RCSA) indicating that one of the one or more repeater access points has detected the radar wave is received from the repeater AP communication step, the RCSA is transmitted to the root access point located one level higher in the WDS, or to a higher level repeater access point located one level higher in the WDS among the one or more repeater access points; In the repeater AP beacon step, when the beacon includes a CSA (Channel Switch Announcement) indicating that a channel used for communication in the WDS is to be changed from a first channel of the plurality of channels to a second channel of the plurality of channels different from the first channel, the beacon being received from the root access point or an upper repeater access point located one level higher in the WDS among the one or more repeater access points, the repeater AP beacon step changes the selected channel used in the repeater AP beacon step and the repeater AP communication step from the first channel to the second channel after transmitting the beacon including the CSA. program.

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