JP6777320B2 - Wireless base station, wireless communication control method of wireless base station - Google Patents

Description

The present invention relates to a radio base station and a radio communication control method for the radio base station.

In recent years, wireless base stations (hereinafter, also referred to as wireless LAN access points) that can perform wireless communication using two or more different frequency bands such as 2.4 GHz band and 5 GHz band have become widespread. WDS (Wireless Distribution System) is a function in which a plurality of wireless LAN access points communicate with each other in the vicinity. WDS wirelessly performs data communication between two or more LANs, and can be used for exchanging data between access points of each wireless LAN or as a dedicated repeater. In either case, WDS exchanges data with a pre-registered partner, physically expands the range of wireless communication, and realizes further convenience of wireless communication. Such wireless LAN relay is described in, for example, Patent Document 1 below.

Further, since a part of the frequency band of the 5 GHz band is also used for various radar waves and satellite communication, wireless LAN access points using these frequency bands can be used for various radar and satellite communication. It is required to avoid interference. For example, a wireless LAN access point is required to operate a DFS (Dynamic Frequency Selection) that changes channels when various radar waves are detected. There is a problem that communication is stopped for at least 1 minute (60 seconds) when DFS operates, and if the conditions are bad (such as when a radar wave is detected again in the destination channel), communication is stopped for a longer period of time.

For example, Patent Document 2 provides a technique for quickly recovering wireless communication with a new channel by changing to the channel being monitored when radio waves such as various radars are detected in communication with two or more LAN feelings. It is disclosed.

JP-A-2009-303170 JP-A-2010-278825

Here, in Patent Document 2, when DFS operates on one wireless LAN access point, the other wireless LAN access point communicating with WDS is urged to change to a communicable channel, and between the wireless LAN access points. Continue communication. At this time, the wireless slave unit connected to each wireless LAN access point can be notified of the channel change only from the wireless LAN access point to which the slave unit itself is connected (for example, CSA (Channel Switch Announcement)). Such).

However, there are cases where the channel change notification in WDS cannot be handled. For example, a wireless slave unit communicates with a wireless LAN access point (hereinafter also referred to as a root AP) that serves as a master unit (root), and operates in multiple repeater modes (mode in which data to be communicated is relayed as it is) in WDS. Consider a case of communicating with a communication terminal of a communication destination via a wireless LAN access point (hereinafter, also referred to as a repeater AP). When a radar wave is detected by a certain repeater AP, the repeater AP changes to a channel other than the currently used channel according to the DFS operation. In this case, the repeater AP that has detected the radar wave notifies another adjacent AP (repeater AP and / or root AP) of the channel to be changed. However, the repeater AP operates with both functions as an access point (operates as a master unit) and a station (operates as a slave unit) in order to relay communication between APs, while the root AP operates as an access. It is operating in point mode (operating as a master unit). As a result, if the repeater AP notifies the channel to be changed once, then detects the radar wave on the changed channel and changes the channel again, the repeater AP and the route AP can no longer communicate with each other, and the repeater AP itself. I can't even find the AP. As a result, communication between a plurality of APs constituting a communication path in WDS cannot be performed, so that communication cannot be performed from the wireless slave unit to the communication terminal of the communication destination.

The present invention has been made to solve the above problems, and in a network using communication (WDS communication) performed between a plurality of wireless LAN access points, a part of the frequency band of the 5 GHz band (for example). , W56, etc.), even if the wireless LAN access point that operates as a repeater in the communication path detects radar waves and operates DFS, the communication path can be quickly used using a new channel. The purpose is to reconfigure and continue wireless communication.

In order to solve the above problems, the wireless base station according to one aspect of the present invention is a wireless terminal in a wireless communication system in which at least one wireless terminal wirelessly communicates with an arbitrary terminal via a plurality of wireless base stations. It is a wireless base station that is directly wirelessly connected to, and also has a wireless IF unit that searches for other wireless base stations, a channel notification unit that receives channel change notifications from other wireless base stations, and channel change notification information. When there is no connection request from another wireless base station within a certain period after receiving the channel change notification, the mode switching unit that switches the mode between the access point mode and the station mode, and the channel changing unit that changes the channel. , It is provided with a communication control unit that notifies the mode switching unit that the access point mode is switched to the station mode in order to search for another radio base station .

According to this, when a DFS operation is performed by detecting a radar wave in another radio base station, the radio base station is connected from an adjacent radio base station without switching from the access point mode to the station mode. By responding to the request, the time during which communication cannot be performed due to mode switching can be reduced, and WDS communication can be resumed promptly.

The mode switching unit, after which to switch to the station mode based on the notification of the communication control unit, the wireless IF unit searches the other wireless base station, the another radio base station uses the channel switching unit The channel is changed to a channel , and then the mode switching unit switches to the access point mode.

According to this, the radio base station switches to the station mode and the channel to be changed even if the connection request from the adjacent radio base station cannot be received by the change channel for a predetermined time after the channel change in the access point mode. Can be obtained by scanning by yourself.

Further, the channel change notification is a notification for changing the channel based on the detection of the radar wave by another radio base station.

According to this, the radio base station can know the information of the channel changed by the DFS operation by detecting the radar wave from the adjacent radio base station.

Further, in order to solve the above problems, in the wireless communication control method of the wireless base station according to one aspect of the present invention, at least one wireless terminal wirelessly communicates with an arbitrary terminal via a plurality of wireless base stations. In a wireless communication system , it is a wireless communication control method of a wireless base station that is directly wirelessly connected to a wireless terminal, and is a channel based on a step of receiving a channel change notification from another wireless base station and information of the channel change notification. Step to change, and if there is no connection request from another wireless base station within a certain period of time after receiving the channel change notification, the step to switch to station mode, search for other wireless base stations, and select the channel to be used. It includes a step of returning to the access point mode after changing to the channel used by the other radio base station.

According to this, the same effect as that of the radio base station is obtained.

According to the present invention, in WDS, even when a radio base station operating as a repeater in a communication path detects a radar wave and DFS operates, the radio base station uses a new channel to quickly perform a communication path. Can be reconfigured to continue wireless communication.

FIG. 1 is an overall view of a wireless communication system including a wireless base station according to an embodiment. FIG. 2 is a block diagram showing a hardware configuration of a radio base station according to an embodiment. FIG. 3 is a block diagram showing a functional configuration of the radio base station according to the embodiment. FIG. 4 is a flow chart showing the operation of the radio base station (repeater) according to the embodiment. FIG. 5 is a flow chart showing the operation of the radio base station (route) according to the embodiment. FIG. 6 is an example of a communication mode of a wireless communication system including the wireless base station according to the embodiment. FIG. 7 is another example of the communication mode of the wireless communication system including the wireless base station according to the embodiment.

Hereinafter, embodiments will be specifically described with reference to the drawings.
Each of the embodiments described below shows a preferred specific example of the present invention. Numerical values, components, arrangement positions and connection forms of components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present invention will be described as arbitrary components constituting the more preferable form. The same components and steps may be designated by the same reference numerals, and the description thereof may be omitted.

(Embodiment)
A wireless communication system including a wireless base station according to the present embodiment will be described.

FIG. 1 is an overall view showing a configuration of a wireless communication system 100 including a wireless base station 1 according to the present embodiment.

As shown in FIG. 1, the wireless communication system 100 includes radio base stations 1, 2 and 3, and communication terminals 10 and 11.

Here, the wireless base stations 2 and 3 are wireless base station devices having the same functions as the wireless base station 1, and the communication terminal 11 is a wireless communication terminal having the same functions as the communication terminal 10. Hereinafter, detailed description of each device will be omitted.

The radio base station 1 is a radio base station device (hereinafter, also referred to as an access point or AP) having a radio communication interface (hereinafter, also referred to as “radio IF”). The wireless base station 1 can establish a communication path R1 with the communication terminal 10 on a predetermined communication channel by using the wireless IF and perform wireless communication.

Further, the wireless base stations 1, 2 and 3 (hereinafter, also referred to as wireless base stations 1 and the like) perform wireless communication by, for example, a wireless IF such as a wireless LAN conforming to the IEEE802.11a, b, g, n standards and the like. .. The wireless base station 1 and the like are arranged so that the communication areas 15 for wireless communication partially overlap each other. By doing so, the radio base stations 1 and the like can transmit and receive communication frames to each other, and WDS communication becomes possible.

Specifically, the wireless base station 1 receives a communication frame addressed to the communication terminal 11 transmitted from the communication terminal 10 through the communication path R1 by the wireless IF, and the received communication frame is adjacent to the wireless base station by the wireless IF. Send to 2. Then, the radio base station 2 transmits the received communication frame to the adjacent radio base station 3 by the radio IF, and the radio base station 3 transmits the communication frame addressed to the communication terminal 11 transmitted from the communication terminal 10 by the radio IF. It is transmitted to the communication terminal 11 through the communication path R2.

In this way, the communication terminal 10 can communicate with the distant communication terminal 11 by WDS communication such as the wireless base station 1.

Further, the wireless base station 1 and the like may have a wired communication interface (hereinafter, also referred to as “wired IF”). The radio base station 1 and the like are connected to the communication terminal 10 by the communication path R1, but it is also possible to use a wired IF instead of the line IF. The same applies to the communication terminal 11 and the communication path R2.

Further, the wireless base station 1 and the like include one or more wireless communication circuits capable of wireless communication in at least the 5 GHz band.

In order to perform WDS communication, it is necessary that the radio IF of the radio base station 1, the radio IF of the radio base station 2, and the radio IF of the radio base station 3 all have the same communication channel. is there.

The communication terminal 10 is a wireless communication terminal that is a communication device (hereinafter, also referred to as a station or STA) having a wireless IF. The communication terminal 10 establishes a communication path R1 with the radio base station 1. The communication terminal 11 is also a wireless communication terminal which is a communication device having a wireless IF. The communication terminal 11 establishes a communication path R2 with the radio base station 3. The communication terminals 10 and 11 are, for example, a PC (Personal Computer), a mobile phone terminal, a smartphone (high-performance mobile phone terminal), a tablet, and the like.

FIG. 2 is a block diagram showing a hardware configuration of a radio base station and a communication terminal according to an embodiment. In FIG. 2, the radio base station 1 will be described as an example, but the radio base stations 2 and 3 and the communication terminals 10 and 11 also have the same hardware configuration as the radio base station 1.

As shown in FIG. 2, these devices include a CPU (Central Processing Unit) 20, a ROM (Read Only Memory) 21, a RAM (Random Access Memory) 22, a storage device 23, and a WNIC (Wireless Network Interface Card). It includes a Network Interface Card) 25 and an internal bus 26 connecting each component. The communication terminals 10 and 11 such as the radio base station 1 do not necessarily have to be provided with the NIC 25.

The CPU 20 is a processor that executes a control program stored in the ROM 21.

The ROM 21 is a read-only storage area for holding a control program or the like.

The RAM 22 is a storage area used as a work area used by the CPU 20 when executing a control program.

The storage device 23 is a storage area for temporarily storing control programs, control information, device information, or information.

WNIC 24 is a wireless communication interface that performs wireless communication. For example, it is a wireless LAN communication interface that conforms to the IEEE802.11a, b, g, n, ac standards, and the like.

The NIC 25 is a wired communication interface that performs wired communication. For example, it is a wired LAN communication interface that conforms to the IEEE802.3 standard and the like.

The internal bus 26 is a bus that electrically connects the CPU 20, ROM 21, RAM 22, storage device 23, WNIC 24, and NIC 25, and exchanges signals.

FIG. 3 is a block diagram showing a functional configuration of the radio base station according to the embodiment.
In FIG. 3, a detailed description will be given using the radio base station 1 as an example, but the radio base stations 2 and 3 have the same functional configuration as the radio base station 1, and detailed description thereof will be omitted below.

As shown in FIG. 3, the radio base station 1 includes a radio IF unit 30, a detection unit 31, a channel change unit 32, a channel notification unit 33, a communication control unit 34, a mode switching unit 35, a connection unit 36, and a storage unit 37. And so on.

The wireless IF unit 30 transmits and receives wireless frames (including data, control commands, etc.) in wireless communication.

Further, the wireless IF unit 30 searches (scans) which channel the adjacent wireless base station is capable of wireless communication, and connects the result (communication availability, communicable channel information, etc.) to the channel change unit 32. Notify department 36.

The wireless IF unit 30 is realized by the CPU 20, ROM 21, RAM 22, storage device 23, WNIC 24, and the like.

The detection unit 31 determines whether or not the radar wave has been detected, and if so, notifies the channel change unit 32 to that effect. In this way, the radio base station 1 includes the detection unit 31 by using the frequency band to which the radar wave (meteorological observation radar, etc.) is assigned among the 5 GHz bands in which the radio base station 1 can wirelessly communicate. This is because it is legally required to constantly monitor and detect radar waves so that DFS operation can be performed in the case of wireless communication.

The detection unit 31 is realized by the CPU 20, the ROM 21, the RAM 22, and the like.

Upon receiving the notification from the detection unit 31, the channel change unit 32 changes to a channel different from the channel used for wireless communication (hereinafter, also referred to as the current channel) (hereinafter, also referred to as the change channel). And also notify the communication control unit 34 that the wireless communication on the current channel will be stopped. The change channel may be predetermined. For example, a plurality of channels that can be used for wireless communication may be stored in the storage unit 37. The plurality of stored channels may be pre-ordered, the order may be determined by the magnitude of the frequency, and the degree of traffic congestion (bandwidth occupancy) based on the history of past used channels. Etc.) may be taken into consideration in the experience to determine the order.

Further, the channel changing unit 32 acquires the channel information (changed channel) received from the adjacent radio base station from the channel notification unit 33. Then, based on the acquired channel information (changed channel), the communication control unit 34 is notified that the current channel is changed to the changed channel.

The channel changing unit 32 is realized by the CPU 20, the ROM 21, the storage device 23, the RAM 22, and the like.

The channel notification unit 33 creates an information notification frame (for example, a management frame) conforming to the IEEE802.11 standard used between radio base stations in WDS communication, and notifies the adjacent radio base station to the communication control unit 34. Instruct. The information notification frame includes information on the change channel determined by the channel change unit 32.

Further, the channel notification unit 33 receives an information notification frame from an adjacent radio base station via the communication control unit 34, extracts a change channel from the information notification frame, or receives a beacon signal from the adjacent radio base station. Channel information is extracted from and notified to the channel change unit 32.

The channel notification unit 33 is realized by the CPU 20, the ROM 21, the storage device 23, the RAM 22, and the like.

The communication control unit 34 performs communication control so as to transmit and receive wireless frames (including data, control commands, etc.) via the wireless IF unit 30.

Further, the communication control unit 34 controls the radio IF unit 30 so as to transmit the information notification frame instructed by the channel notification unit 33 to the adjacent radio base stations.

The communication control unit 34
(A) When the detection unit 31 detects a radar wave, it waits for wireless communication on the change channel based on the notification (change channel) of the channel change unit 32, and stops the wireless communication on the current channel. Controls the wireless IF unit 30.
(B) When the detection unit 31 does not detect the radar wave and the information notification frame is received from the adjacent radio base station, the information notification frame is notified to the channel notification unit 33. Then, based on the notification of the changed channel extracted by the channel changing unit 32, the wireless IF unit 30 is controlled so as to wait so that the wireless communication can be performed on the changed channel and stop the wireless communication on the current channel.

When the communication control unit 34 receives the information notification frame including the change channel information, it waits for a certain period (for example, 1 minute) and waits for a certain period of time (for example, 1 minute).
(C) If there is no connection request from the neighboring wireless base station, if the own device is the root AP, performs the notification of switching the mode to the mode switching unit 35, if its own device is a repeater AP, the mode switching section Notify 35 to that effect. Here, the notification that the mode is switched to the mode switching unit 35 when the own device is the root AP is specifically referred to from the access point mode (hereinafter, also referred to as AP mode) to the station mode (hereinafter, also referred to as STA mode). ) Is a notification to switch to.
(D) When there is a connection request from an adjacent radio base station, the connection unit 36 is notified to that effect.

The communication control unit 34 is realized by the CPU 20, the ROM 21, the RAM 22, the storage device 23, and the like.

The mode switching unit 35 can alternately switch between the access point mode and the station mode based on the notification of the communication control unit 34, and notifies the connection unit 36 that the mode has been switched.

Further, referring to the initial setting of the radio base station stored in the storage unit 37, it is determined whether the radio base station operates in the AP mode or both the AP mode and the STA mode. Here, when operating in AP mode, the wireless base station is set as the root (master unit), and when operating in both AP mode and STA mode, the wireless base station is set as the repeater (slave unit). Judge that it has been done.

The mode switching unit 35 is realized by the CPU 20, the ROM 21, the RAM 22, the storage device 23, and the like.

The connection unit 36 notifies the communication control unit 34 to make a connection request to the adjacent radio base station based on the notification of the mode switching unit 35 (to the effect of switching to the STA mode), and the connection unit 36 notifies the adjacent radio base via the radio IF. Make a connection request to the station. Specifically, it is a probe request in wireless communication.

Further, the connection unit 36 notifies the communication control unit 34 that the connection response is made to the adjacent wireless base station based on the notification of the communication control unit 34 (notification that there is a connection request from the adjacent wireless base station). Then, the connection response is transmitted to the adjacent radio base station via the radio IF. Specifically, it is a probe response in wireless communication.

Further, when the connection unit 36 receives a connection request from an adjacent wireless base station via the wireless IF unit 30, the connection unit 36 performs connection processing with the adjacent wireless base station and performs wireless communication. Specifically, the connection process is a process such as authentication and association after mutual confirmation of the channel used, modulation method, etc. is obtained in order to establish wireless communication.

The connection unit 36 is realized by the CPU 20, the ROM 21, the RAM 22, the storage device 23, and the like.

The storage unit 37 stores initial settings related to wireless communication (for example, operation settings such as root AP or repeater AP, SSID, encryption key, etc.). The initial settings may be preset at the time of shipment from the factory, or may be set by the user using a tool provided in the device.

The storage unit 37 is also used as a temporary buffer for communication in wireless communication.

The storage unit 37 is realized by a CPU 20, a ROM 21, a RAM 22, a storage device 23, and the like.

FIG. 4 is an example of a flowchart showing the operation of the radio base station according to the embodiment.

Here, in FIG. 4, among the 5 GHz band, the plurality of radio base stations according to the embodiment use channels in a part of the frequency band (for example, W56) that needs to be accompanied by DFS operation when detecting a radar wave. Then, in the situation where WDS communication is performed, the radio base station 2 which is a repeater performs DFS operation after detecting the radar wave by itself, and then uses a new channel (here, a change channel) to perform a plurality of operations. It shows the operation until WDS communication is restarted between the radio base stations of.

In step S401, the detection unit 31 determines whether or not a radar wave has been detected in the current channel performing WDS communication. When the detection unit 31 detects a radar wave, the detection unit 31 transitions to step S402 (Yes in step S401). If the detection unit 31 has not detected the radar wave, the detection unit 31 returns to the original state and repeats step S401 (No in step S401).

In step S402, the fact that the radar wave has been detected from the channel notification unit 33 and the information notification frame (channel change notification) including the change channel are transmitted to the adjacent AP via the radio IF unit 30.

In step S403, the communication control unit 34 controls the wireless IF unit 30 so as to stop the wireless communication on the current channel.

In step S404, the communication control unit 34 waits so that wireless communication can be performed on the changed channel changed based on the notification from the channel changing unit 32.

In step S405, the detection unit 31 determines whether or not the radar wave is detected within the statutory predetermined time T in the change channel. If it is determined that the detection unit 31 has detected the radar wave, the process proceeds to step S406 (Yes in step S405). If the detection unit 31 does not detect the radar wave, the detection unit 31 transitions to step S407 (No in step S405).

In step S406, the channel change unit 32 re-changes the change channel changed from the current channel in step S404 based on a channel different from the change channel used in step S404 and a new predetermined change channel. Then, the communication control unit 34 is notified to that effect. After that, the process returns to step S405, and the communication control unit 34 confirms the presence or absence of radar waves on the re-changed new channel.

In step S407, the connection unit 36 notifies the communication control unit 34 that the connection request is made to the adjacent radio base station, and makes the connection request to the adjacent radio base station via the wireless IF.

In step S408, the connection unit 36 determines whether or not a connection response has been received from the adjacent radio base station. When the connection unit 36 receives the connection response, the connection unit 36 transitions to step S409 (Yes in step S408). On the other hand, when the connection response is not received, step S408 is repeated and the reception of the connection response is waited for (No in step S408).

In step S409, based on the fact that the connection response is received (Yes in step S408), the connection unit 36 performs connection processing with the adjacent radio base station and restarts WDS communication.

FIG. 5 is an example of a flowchart showing the operation of the radio base station according to the embodiment.

Here, FIG. 5 shows a radio base station according to an embodiment that operates on the same premise as that of FIG. 4, and in particular, a radio base station operating as a root (master unit) function operates as a repeater function. It shows the process from receiving the notification of the channel change based on the DFS function from the existing radio base station to restarting WDS communication with the same radio base station.

In step S501, the channel notification unit 33 determines whether or not the information notification frame from the adjacent radio base station has been received via the communication control unit 34. When the channel notification unit 33 receives the information notification frame, the channel notification unit 33 transitions to step S502 (Yes in step S501). On the other hand, if it is not received, step S501 is repeated and waits (No in step S501).

In step S502, the communication control unit 34 controls the wireless IF unit 30 so as to stop the wireless communication on the current channel based on the notification of the channel change unit 32.

In step S503, the communication control unit 34 stands by so that wireless communication can be performed on the change channel based on the notification from the channel change unit 32.

In step S504, based on the notification from the communication control unit 34, it is determined whether or not a connection request has been received from the adjacent radio base station within the predetermined time T via the radio IF unit 30. When the connection request is received, the process proceeds to step S509 (Yes in step S504). On the other hand, if the connection request is not received, the process proceeds to step S505 (No in step S504).

In step S505, the mode switching unit 35 switches the communication mode from the AP mode to the STA mode based on the notification from the communication control unit 34, and notifies the connection unit 36 to that effect.

In step S506, the wireless IF unit 30 searches for a channel capable of wireless communication with an adjacent wireless base station. When the radio IF unit 30 can acquire channel information capable of communicating with the adjacent radio base station as a result of the search, the radio IF unit 30 notifies the channel change unit 32 and proceeds to step S507 (Yes in step S506). On the other hand, as a result of the search, if the adjacent radio base station cannot acquire the channel information that can be communicated with, step S506 is repeated and the search is continued (No in step S506).

In step S507, the channel changing unit 32 newly wirelessly sets the changed channel changed from the current channel in step S503 based on the channel information that the adjacent radio base station acquired by the radio IF unit 30 can communicate with. The adjacent radio base station acquired by the IF unit 30 changes to a communicable channel again, and notifies the communication control unit 34 to that effect. The communication control unit 34 waits so that wireless communication can be performed on the re-changed channel.

In step S508, after the process of step S507, the mode switching unit 35 switches the communication mode from the STA mode to the AP mode based on the notification of the communication control unit 34, and notifies the connection unit 36 to that effect. Return to step S504.

In step S509, the connection unit 36 notifies the adjacent wireless base station that it makes a connection response based on the notification of the communication control unit 34 (notification that there is a connection request from the adjacent wireless base station). It notifies 34 and transmits a connection response to an adjacent radio base station that has received the connection request via the radio IF.

In step S510, based on the fact that the connection request is received (Yes in step S509), the connection unit 36 performs connection processing with the adjacent wireless base station and restarts WDS communication.

FIG. 6 is an example of a communication mode of a wireless communication system including the wireless base station according to the embodiment.

In FIG. 6, when a plurality of radio base stations according to the embodiment described in FIGS. 4 and 5 detect a radar wave in the 5 GHz band, a part of the frequency band (for example, W56) that needs to be accompanied by DFS operation). Wireless base station 2 (repeater) detects radar waves during WDS communication with each other and then performs DFS operation, and then uses a new channel to perform WDS communication between multiple wireless base stations. It shows until it resumes. Here, assuming that the radio base station 1 is operating in the AP mode, description will be made below with reference to each step of FIGS. 4 and 5. The code of the step uses the code of FIGS. 4 and 5. In FIG. 6, radio base stations 1 and 2 are referred to as AP1 and AP2, respectively.

In FIG. 6, first, when the AP2 (repeater) detects a radar wave (Yes in step S401), it transmits an information notification frame (channel change notification) including a change channel to AP1 (route) (step S402). .. The AP adjacent to the AP2 is other than the AP1 (for example, in FIG. 1, the radio base station 2 is adjacent to the radio base station 3 in addition to the radio base station 1), but the description is omitted for the sake of simplicity. .. The communication control unit 34 of AP1 and AP2 controls the wireless IF unit 30 so as to stop the wireless communication on the current channel based on the notification of each channel change unit 32 (steps S403 and S502). Next, the communication control unit 34 of AP1 and AP2 changes the channel and waits for wireless communication on the changed channel (steps S404 and S503). Then, when the AP1 receives the connection request from the AP2 within the predetermined time T (Yes in steps S407 and S504), the AP1 transmits a connection response to the AP2, establishes wireless communication, and resumes the communication (steps S509 and 510). ).

In the communication mode of FIG. 6, the AP1 can respond to the connection request from the AP2 without switching from the AP mode operating as the root (master unit) function to the STA mode. In this way, the AP1 can quickly resume wireless communication with the AP2 by reducing the time during which communication cannot be performed due to mode switching, and can promptly resume WDS communication between a plurality of wireless base stations.

FIG. 7 is another example of the communication mode of the wireless communication system including the wireless base station according to the embodiment.

In FIG. 7, in the same system environment as in FIG. 6, description will be given below with reference to each step of FIGS. 4 and 5. However, in FIG. 7, the radar wave is detected in the current channel during which AP2 is communicating, and the change channel is performed in accordance with the DFS operation. The AP2 is different from FIG. 6 in that it assumes a communication mode in which a radar wave is detected again within a statutory predetermined standby time prior to performing wireless communication on the changed channel.

In FIG. 7, first, when the AP2 (repeater) detects a radar wave (Yes in step S401), it transmits an information notification frame (channel change notification) including a change channel to AP1 (route) (step S402). The communication control unit 34 of AP1 and AP2 controls the wireless IF unit 30 so as to stop the wireless communication on the current channel based on the notification of each channel change unit 32 (steps S403 and S502). Next, the communication control unit 34 of AP1 and AP2 changes the channel and waits for wireless communication on the changed channel (steps S404 and S503).

On the other hand, AP2 detects the radar wave again during the statutory standby time (Yes in step S405) and changes the channel again prior to starting communication on the changed channel (step S406). Therefore, AP1 cannot receive the connection request from AP2 within the predetermined time T (No in step S504). This is because the channels used are no longer different. In this case, the mode switching unit 35 of AP1 switches the operation mode from the AP mode to the STA mode (step S505). This allows AP1 to scan adjacent APs and send connection requests by itself.

Next, AP1 confirms whether or not AP2 exists in the changed channel, scans AP2 and detects it (Yes in step S506), and when the communication control unit 34 detects AP2, the channel information extracted from the beacon signal is extracted. It receives from the channel notification unit 33 and stands by so that wireless communication can be performed on the channel (step S507). Then, in AP1, the mode switching unit 35 switches the operation mode from the STA mode to the AP mode (step S508). This allows AP1 to receive the connection request from AP2 again. Next, when the AP1 receives a connection request from the AP2 within a predetermined time (step S407), the AP1 makes a connection response to the AP2, establishes wireless communication, and resumes the communication (steps S509 and S510).

In this way, AP1 and AP2 resume WDS communication using the modified channel with each other.

In the communication mode of FIG. 7, the AP1 switches to the STA mode and scans the changed channel by itself even if the connection request from the repeater AP2 cannot be received by the changed channel for a predetermined time after the channel is changed in the AP mode. Acquire by doing so, perform wireless communication with AP2, and maintain WDS communication. That is, even if the changed channel is changed from the current channel to the changed channel by the AP2 and then the changed channel is changed to the new channel again due to the DFS operation by detecting the radar wave within the predetermined time, the change channel is promptly changed. WDS communication can be resumed and maintained.

As described above with reference to each figure, the radio base station (particularly the route and the master unit) according to the embodiment performs DFS operation by detecting the radar wave at the other radio base station (particularly the repeater). By responding to the connection request from the adjacent wireless base station (repeater) without switching from the AP mode to the STA mode, the time during which communication cannot be performed due to the mode switching can be reduced, and the embodiment can be promptly implemented. WDS communication can be resumed within the communication system according to the above.

Further, when the radio base station (particularly the route, the master unit) according to the embodiment cannot receive the connection request from the adjacent radio base station (repeater) on the change channel for a predetermined time after the channel is changed in the AP mode. However, it is possible to switch to the STA mode, acquire it by scanning the channel to be changed by itself, perform wireless communication with AP2, and resume WDS communication. That is, after the adjacent radio base station (repeater) changes from the current channel to the changed channel, the adjacent radio base station (repeater) detects the radar wave again within a predetermined time, so that a new DFS operation is performed. Even if the channel is changed from moment to moment, WDS communication can be restarted and maintained promptly.

In this way, the radio base station (particularly the route, the master unit) according to the embodiment is in an environment where WDS communication is performed on a channel in the 5 GHz band, even when it is accompanied by DFS operation by detecting radar waves. , WDS communication can be resumed and maintained promptly.

The present invention is useful in WDS communication performed between a plurality of radio base stations when a radio base station operating as a repeater in a communication path detects a radar wave and DFS operates.

1. AP1 wireless base station (route)
2, 3, AP2, AP3 radio base station (repeater)
10, 11 Communication terminal 15 Communication area 100 Wireless communication system R1, R2 Communication path 20 CPU
21 ROM
22 RAM
23 Storage device 24 WNIC
25 NIC
26 Internal bus 31 Detection unit 32 Channel change unit 33 Channel notification unit 34 Communication control unit 35 Mode switching unit 36 Connection unit 37 Storage unit

Claims (4)

In a wireless communication system in which at least one wireless terminal wirelessly communicates with an arbitrary terminal via a plurality of wireless base stations, the wireless base station is directly wirelessly connected to the wireless terminal.
A wireless IF section that searches for other wireless base stations,
A channel notification unit that receives channel change notifications from other wireless base stations,
A channel change unit that changes the channel based on the information in the channel change notification,
A mode switching unit that switches the mode between access point mode and station mode,
If there is no connection request from another wireless base station within a certain period of time after receiving the channel change notification, the mode switching unit is notified that the access point mode is switched to the station mode in order to search for another wireless base station. Communication control unit and
A wireless base station equipped with. After the mode switching unit switches to the station mode based on the notification of the communication control unit, the wireless IF unit searches for another wireless base station, and the channel changing unit searches for the other wireless base station. The channel is changed to the channel to be used, and then the mode switching unit switches to the access point mode.
The radio base station according to claim 1. The radio base station according to claim 1 or 2, wherein the channel change notification is a notification that the channel is changed based on the detection of the radar wave by the other radio base station. In a wireless communication system in which at least one wireless terminal wirelessly communicates with an arbitrary terminal via a plurality of wireless base stations, the wireless communication control method of the wireless base station which is directly wirelessly connected to the wireless terminal.
Steps to receive channel change notifications from other radio base stations,
The step of changing the channel based on the information of the channel change notification, and
If there is no connection request from another wireless base station within a certain period after receiving the channel change notification, the step of switching to the station mode and
A radio communication control method including a step of searching for another radio base station, changing the channel used to the channel used by the other radio base station, and then returning to the access point mode.