JP2019047333A - Radio base station, radiocommunication control method of radio base station - Google Patents

Abstract

To reduce the time until reconstitution of communication incident to radar wave detection, in inter-office communication by WDS performed among multiple radio base stations.SOLUTION: Ia a radio communication system where at least one radio terminal performs radio communication with an arbitrary terminal via multiple radio base stations, the radio base station in direct wireless connection with the radio terminal includes a radio IF section for retrieving other radio base station, a channel notification section for receiving channel change notification from other radio base station, a channel change section for changing the channel on the basis of the information of the channel change notification, a mode changeover section for changing over the mode between access point mode and station mode, and a communication control section for notifying the mode changeover section of mode changeover, when there is no connection request from other radio base station within a fixed period after receiving the channel change notification.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a wireless base station and a wireless communication control method of the wireless base station.

  In recent years, a wireless base station (hereinafter, also referred to as a wireless LAN access point) is widely used which can perform wireless communication using two or more different frequency bands such as a 2.4 GHz band and a 5 GHz band. A wireless distribution system (WDS) 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 may be used as access points for wireless LANs exchanging data with each other, and as a dedicated repeater. In either case, the WDS exchanges data with a previously registered party, physically expands the range of wireless communication, and realizes further convenience of wireless communication. The relay of such a wireless LAN is described, for example, in Patent Document 1 below.

  In addition, since some frequency bands in the 5 GHz band are also used for various radar waves and satellite communications, etc., wireless LAN access points using these frequency bands are required for various radar and satellite communications. It is required to avoid interference. For example, the wireless LAN access point is required to perform an operation of dynamic frequency selection (DFS) that changes channels when various radar waves are detected. There is a problem that communication will stop for a longer time if the condition is bad (for example, when a radar wave is detected again in the channel to which it has moved) for at least 1 minute (60 seconds) when DFS operates.

  For example, in Patent Document 2, when radio waves of various radars are detected in two or more LAN-like communications, a technique for changing to a channel being monitored and quickly recovering wireless communication with a new channel is disclosed in It is disclosed.

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

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

  However, there are cases where channel change notification in WDS can not be handled. For example, a wireless slave unit communicates with a wireless LAN access point (hereinafter also referred to as a root AP) serving as a master unit (route), and operates in a plurality of repeater modes (a mode for relaying data to be communicated as it is) in WDS. Consider a case where communication is performed with a communication terminal of a communication destination via a wireless LAN access point (hereinafter, also referred to as repeater AP). When a repeater AP detects a radar wave, 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 the adjacent AP (repeater AP and / or route AP) of the channel to be changed. However, the repeater AP operates with both functions as an access point (operating as a master) and a station (operating as a slave) to relay communication between APs, while the root AP accesses It is operating in point mode (operating as a parent device). As a result, once the repeater AP notifies the channel to be changed, if the radar wave is detected on the channel to be changed and the channel is changed again, communication between the repeater AP and the root AP can no longer be performed, and the root AP I can not find an AP. As a result, communication can not be performed between the wireless slave unit and the communication terminal of the communication destination, because communication between the plurality of APs constituting the communication path can not be performed by the WDS.

  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 (for example, 5 GHz band) (for example, , W56, etc.) in the wireless LAN access point operating as a repeater in the communication path, even if the radar wave is detected and the DFS operates, the communication path is promptly performed using the new channel. In order to continue the wireless communication.

  In order to solve the above problems, a wireless base station according to an aspect of the present invention is a wireless communication system in which at least one wireless terminal wirelessly communicates with any terminal via a plurality of wireless base stations. A wireless base station directly connected wirelessly with a wireless IF unit for searching for other wireless base stations, a channel notification unit for receiving 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 of time after receiving a channel change notification, a channel change unit that changes the channel to and a mode change unit that switches the mode between access point mode and station mode And a communication control unit for notifying the mode switching unit of the mode switching.

  According to this, when the radio base station performs the DFS operation by detecting the radar wave in another radio base station, the connection from the adjacent radio base station is performed without switching from the access point mode to the station mode. By responding to the request, it is possible to reduce the time during which communication caused by mode switching can not be performed, and WDS communication can be resumed promptly.

  Also, after the mode switching unit switches to the station mode based on the notification from the communication control unit, the wireless IF unit searches for another wireless base station, and the channel changing unit uses the channel used by the other wireless base station. Switch to access point mode after changing the channel to.

  According to this, the radio base station switches to the station mode even if it can not receive a connection request from the adjacent radio base station for a predetermined time after channel change in the access point mode, and the channel to be changed You can get it by scanning it yourself.

  The channel change notification is a notification for changing the channel based on the detection of the radar wave by another wireless base station.

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

  Further, in order to solve the above problems, in the wireless communication control method of a wireless base station according to an 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 method, a wireless communication control method of a wireless base station directly connected wirelessly to a wireless terminal, comprising the steps of: receiving a channel change notification from another wireless base station; The step of changing the station mode, the step of switching to the station mode if there is no connection request from another wireless base station within a fixed period after receiving the channel change notification, the other wireless base station is searched, and the channel used And returning to the access point mode after changing to a channel used by the other radio base station.

  According to this, the same effect as that of the wireless base station can be obtained.

  According to the present invention, in the WDS, even if the radio base station operating as a repeater in the communication path detects a radar wave in the WDS and the DFS operates, the radio base station can quickly communicate using the new channel. And 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 the hardware configuration of the radio base station according to the embodiment. FIG. 3 is a block diagram showing a functional configuration of the radio base station according to the embodiment. FIG. 4 is a flowchart 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 a communication mode of the wireless communication system including the wireless base station according to the embodiment.

Embodiments will be specifically described below with reference to the drawings.
Each of the embodiments described below shows a preferable specific example of the present invention. Numerical values, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, components not described in the independent claim indicating the highest concept of the present invention will be described as optional components constituting a more preferable embodiment. In addition, the same code | symbol may be attached | subjected to the same component and step, and description may be abbreviate | omitted.

Embodiment
A radio communication system including the radio 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 the wireless base station 1 according to the present embodiment.

  As shown in FIG. 1, the wireless communication system 100 includes wireless 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 function as the wireless base station 1, and the communication terminal 11 is a wireless communication terminal having the same function as the communication terminal 10. The detailed description of each device will be omitted hereinafter.

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

  Also, the wireless base stations 1, 2 and 3 (hereinafter also referred to as wireless base station 1 etc.) perform wireless communication using a wireless IF such as a wireless LAN conforming to the IEEE 802.11a, b, g, n standards, etc. . The wireless base stations 1 and the like are arranged such that the communication areas 15 of wireless communication partially overlap each other. By doing this, the radio base station 1 and so forth can transmit and receive communication frames to each other, enabling WDS communication.

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

  As described above, the communication terminal 10 can communicate with the distant communication terminal 11 by the WDS communication of the wireless base station 1 or the like.

  In addition, the wireless base station 1 and the like may have a wired communication interface (hereinafter, also referred to as a “wired IF”). The wireless base station 1 and the like are connected to the communication terminal 10 through the communication route 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 route R2.

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

  In order to perform WDS communication, it is necessary that all communication channels used by the wireless IF of the wireless base station 1, the wireless IF of the wireless base station 2, and the wireless IF of the wireless base station 3 are the same. is there.

  The communication terminal 10 is a wireless communication terminal which is a communication apparatus having a wireless IF (hereinafter, also referred to as a station or an STA). 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 route 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 smart phone (high-performance mobile phone terminal), a tablet or the like.

  FIG. 2 is a block diagram showing a hardware configuration of the radio base station and the communication terminal according to the embodiment. Although the radio base station 1 is described as an example in FIG. 2, 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 central processing unit (CPU) 20, a read only memory (ROM) 21, a random access memory (RAM) 22, a storage device 23, a wireless network interface card (WNIC) 24, and an NIC A network interface card 25 and an internal bus 26 connecting the respective components are provided. The radio base stations 1 and the like and the communication terminals 10 and 11 do not necessarily have to have 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 that holds control programs and the like.

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

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

  The WNIC 24 is a wireless communication interface that performs wireless communication. For example, it is a communication interface of a wireless LAN conforming to the IEEE 802.11a, b, g, n, ac standard or the like.

  The NIC 25 is a wired communication interface that performs wired communication. For example, it is a wired LAN communication interface conforming to the IEEE 802.3 standard or the like.

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

FIG. 3 is a block diagram showing a functional configuration of the radio base station according to the embodiment.
Although the wireless base station 1 will be described in detail in FIG. 3 as an example, the wireless base stations 2 and 3 have the same functional configuration as the wireless base station 1, and the detailed description will be omitted hereinafter.

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

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

  Also, the wireless IF unit 30 searches (scans) on which channel the adjacent wireless base station is capable of wireless communication, and connects the channel change unit 32 with the result (communication availability, communicable channel information, etc.) Report to section 36.

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

  The detection unit 31 determines whether a radar wave has been detected, and if so, notifies the channel change unit 32 to that effect. As described above, the wireless base station 1 includes the detection unit 31 by using a frequency band to which a radar wave (such as a weather observation radar) or the like is allocated in the 5 GHz band in which the wireless base station 1 can perform wireless communication. In the case of wireless communication, it is legally required to always monitor and detect radar waves so as to be able to perform DFS operation.

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

  The channel change unit 32 receives the notification from the detection unit 31, and changes the channel notification unit 33 to change to a channel different from the channel currently used for wireless communication (hereinafter also referred to as current channel) (hereinafter also referred to as change channel). And notify the communication control unit 34 that the wireless communication on the current channel is to be stopped. The change channel may be predetermined. For example, a plurality of channels usable for wireless communication may be stored in the storage unit 37. The plurality of stored channels may be ordered in advance, or the order may be determined by the magnitude of the frequency. In addition, traffic congestion degree (band occupancy degree based on the past used channel history) The order may be determined taking account of experience).

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

  The channel change 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 IEEE 802.11 standard used between wireless base stations in WDS communication, and causes the communication control unit 34 to notify adjacent wireless base stations. Instruct The information notification frame includes information on the changed channel determined by the channel change unit 32.

  Also, the channel notification unit 33 receives an information notification frame from an adjacent wireless base station via the communication control unit 34, extracts a changed channel from the information notification frame, or receives a beacon signal from an adjacent wireless base station Channel information is extracted 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 to transmit and receive wireless frames (including data and control commands) via the wireless IF unit 30.

  Further, the communication control unit 34 controls the wireless IF unit 30 to transmit the information notification frame instructed from the channel notification unit 33 to the adjacent wireless base station.

The communication control unit 34
(A) When a radar wave is detected by the detection unit 31, on the basis of the notification (changed channel) of the channel change unit 32, standby is made to be able to perform wireless communication on the changed channel, and wireless communication on the current channel is stopped. Control the wireless IF unit 30.
(B) When the detection unit 31 detects no radar wave and receives an information notification frame from an adjacent wireless base station, the channel notification unit 33 is notified of the information notification frame. Then, on the basis of the notification of the changed channel extracted by the channel changing unit 32, it waits for wireless communication on the changed channel, and controls the wireless IF unit 30 to stop wireless communication on the current channel.

When the communication control unit 34 receives an information notification frame including changed channel information, the communication control unit 34 stands by for a fixed period (for example, one minute),
(C) When there is no connection request from an adjacent wireless base station, if the own device is the route AP, the mode switching unit 35 is notified that the mode is switched, and if the own device is the repeater AP, the mode switching unit Notify that to 35. Here, if the own apparatus is the root AP, the notification to the effect that the mode is switched to the mode switching unit 35 is specifically called from access point mode (hereinafter also referred to as AP mode) to station mode (hereinafter also referred to as STA mode). Notification to switch to).
(D) When there is a connection request from an adjacent wireless base station, the connection unit 36 is notified of that.

  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 the access point mode and the station mode based on the notification from the communication control unit 34, and notifies the connection unit 36 that the mode has been switched.

  Further, with reference to the initial setting of the wireless base station stored in the storage unit 37, it is determined whether the wireless base station operates in the AP mode or in both the AP mode and the STA mode. Here, when operating in the AP mode, the wireless base station is set as the root (master unit), and when operating in both the AP mode and the STA mode, the wireless base station is set as the repeater (slave unit) It is judged that it is 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 (indication to switch to the STA mode), and the adjacent radio base via the radio IF Make a connection request to the station. Specifically, it is a probe request or the like in wireless communication.

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

  Furthermore, when the connection unit 36 receives a connection request from the adjacent wireless base station via the wireless IF unit 30, the connection unit 36 performs connection processing with the adjacent wireless base station to perform wireless communication. Specifically, the connection processing is processing such as authentication, association, etc. after mutual confirmation of a used channel, modulation scheme, etc. is taken 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 (for example, operation settings such as the route AP or the repeater AP, an SSID, an encryption key, and the like) regarding wireless communication. The initial settings may be preset at the time of shipment from the factory, or may be set by the user using tools provided in the apparatus.

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

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

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

  Here, in FIG. 4, a plurality of radio base stations according to the embodiment use channels of a part of frequency bands (for example, W56 etc.) that need to be accompanied by DFS operation when detecting radar waves in the 5 GHz band. Then, in a situation where WDS communication is being performed, the radio base station 2 which is a repeater performs DFS operation after detecting its own radar wave, and then, using the new channel (here, the change channel) The operation until WDS communication is resumed between the wireless base stations of FIG.

  In step S401, the detection unit 31 determines whether a radar wave has been detected in the current channel in which WDS communication is performed. If the detection unit 31 detects a radar wave, the process proceeds to step S402 (Yes in step S401). When the detection unit 31 does not detect a radar wave, the detection unit 31 returns to the original state and repeats step S401 (No in step S401).

  In step S402, the channel notification unit 33 transmits an information notification frame (channel change notification) including the detection of the radar wave and the change channel to the adjacent AP via the wireless IF unit 30.

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

  In step S404, the communication control unit 34 waits for wireless communication on the changed channel changed based on the notification from the channel change unit 32.

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

  In step S406, the channel change unit 32 rechanges the changed channel changed from the current channel in step S404 based on a channel different from the changed channel used in step S404 and a new change channel determined in advance. And notify the communication control unit 34 to that effect. Thereafter, the process returns to step S405, and the communication control unit 34 confirms the presence or absence of a radar wave on the new changed channel that has been changed again.

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

  In step S408, connection unit 36 determines whether a connection response has been received from an adjacent wireless base station. When the connection unit 36 receives the connection response, the process proceeds to step S409 (Yes in step S408). On the other hand, when the connection response is not received, step S408 is repeated, and reception of the connection response is awaited (No in step S408).

  In step S409, the connection unit 36 performs connection processing with the adjacent radio base station based on the reception of the connection response (Yes in step S408), and resumes the WDS communication.

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

  Here, in FIG. 5, the radio base station according to the embodiment operates on the same premise as FIG. 4, and in particular, the radio base station operating as a route (master device) function operates as a repeater function. It shows from the notification of the channel change based on the DFS function of the existing radio base station until the restart of WDS communication with the same radio base station.

  In step S501, the channel notification unit 33 determines whether an information notification frame from an adjacent wireless 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, when not receiving, step S501 is repeated and it waits (No of step S501).

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

  In step S503, based on the notification from the channel change unit 32, the communication control unit 34 waits for wireless communication on the changed channel.

  In step S504, based on the notification from the communication control unit 34, it is determined whether a connection request has been received from the adjacent wireless base station within the predetermined time T via the wireless IF unit 30. If a connection request has been received, the process proceeds to step S509 (Yes in step S504). On the other hand, when the connection request has not been 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 the adjacent wireless base station. If the wireless IF unit 30 can obtain channel information capable of communicating with the adjacent wireless base station as a result of the search, the wireless IF unit 30 notifies the channel changing unit 32 and transitions to step S507 (Yes in step S506). On the other hand, when the adjacent radio base station can not acquire communicable channel information as a result of the search, step S506 is repeated and the search is continued (No in step S506).

  In step S507, the channel changing unit 32 newly wirelessly transmits the changed channel changed from the current channel in step S503 based on the channel information that can be communicated by the adjacent wireless base station acquired by the wireless IF unit 30. The adjacent radio base station acquired by the IF unit 30 is changed again to a communicable channel, and the communication control unit 34 is notified of that. The communication control unit 34 stands by for the wireless communication on the channel changed again.

  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 from the communication control unit 34, and notifies the connection unit 36 to that effect. It returns to step S504.

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

  In step S510, the connection unit 36 performs connection processing with the adjacent radio base station based on the reception of the connection request (Yes in step S509), and restarts the 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 wireless base stations according to the embodiment described in FIG. 4 and FIG. 5 detect a radar wave in the 5 GHz band, a part of frequency bands (for example, W56 etc.) required to be accompanied by DFS operation The radio base station 2 (repeater) detects a radar wave during WDS communication with each other and performs DFS operation, and then WDS communication is performed between a plurality of radio base stations using a new channel. It shows until it resumes. Here, assuming that the radio base station 1 is operating in the AP mode, the following description will be made with reference to the respective steps of FIG. 4 and FIG. The code of the step uses the code of FIG. 4 and FIG. In FIG. 6, the wireless base stations 1 and 2 will be referred to as AP1 and AP2, respectively.

  In FIG. 6, first, when the AP 2 (repeater) detects a radar wave (Yes in step S401), it transmits an information notification frame (channel change notification) including the change channel to the AP 1 (route) and the change channel (step S402). . Note that there are APs adjacent to AP2 other than AP1 (for example, in FIG. 1, the wireless base station 2 is adjacent to the wireless base station 3 other than the wireless base station 1), but will be omitted to simplify the explanation. . The communication control units 34 of the APs 1 and 2 control the wireless IF unit 30 to stop the wireless communication on the current channel based on the notification of each of the channel change units 32 (steps S403 and S502). Next, the communication control units 34 of the APs 1 and 2 change channels and stand by for wireless communication on the changed channel (steps S404 and S503). Then, when AP1 receives a connection request from AP2 within a predetermined time T (Yes in steps S407 and S504), it transmits a connection response to AP2, establishes wireless communication, and resumes communication (steps S509 and 510). ).

  In the communication mode of FIG. 6, the AP 1 can respond to the connection request from the AP 2 without switching from the AP mode operating as a root (master device) function to the STA mode. As described above, the AP 1 can promptly resume wireless communication with the AP 2 by reducing time when communication caused by mode switching can not be performed, and can quickly resume WDS communication performed between a plurality of wireless base stations.

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

  7 will be described below with reference to the respective steps of FIG. 4 and FIG. 5 in a system environment similar to FIG. However, FIG. 7 detects a radar wave in the current channel in which the AP 2 is in communication, and performs a change channel in accordance with the DFS operation. The AP 2 is different from that in FIG. 6 in that it assumes a communication mode in the case where a radar wave is detected again within a legal predetermined standby time prior to performing wireless communication on the changed channel.

  In FIG. 7, first, when the AP 2 (repeater) detects a radar wave (Yes in step S 401), it transmits an information notification frame (channel change notification) including a change channel to the AP 1 (route) (step S 402). The communication control units 34 of the APs 1 and 2 control the wireless IF unit 30 to stop the wireless communication on the current channel based on the notification of each of the channel change units 32 (steps S403 and S502). Next, the communication control units 34 of the APs 1 and 2 change channels and stand by for wireless communication on the changed channel (steps S404 and S503).

  On the other hand, AP2 detects the radar wave again during the legal standby time before starting communication on the changed channel (Yes in step S405), and changes the channel again (step S406). For this reason, AP1 can not receive a connection request from AP2 within a predetermined time T (No in step S504). This is because the channels used are no longer consistent. 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 enables the AP 1 to scan adjacent APs itself or transmit a connection request.

  Next, AP1 confirms whether or not AP2 exists in the change channel, and scans and detects AP2 (Yes in step S506), the channel information extracted from the beacon signal in which the communication control unit 34 detects AP2 is It receives from the channel notification unit 33, and stands by for wireless communication 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 enables AP1 to receive the connection request from AP2 again. Next, when AP 1 receives a connection request from AP 2 within a predetermined time (step S 407), AP 1 responds to AP 2, establishes wireless communication, and resumes communication (steps S 509 and S 510).

  In this way, APs 1 and 2 resume WDS communication using each other's change channel.

  In the communication mode of FIG. 7, AP1 switches to STA mode even if it can not receive a connection request from AP2 of the repeater for a predetermined time after channel change in AP mode, and scans itself for the channel to be changed. And wirelessly communicate with AP 2 to maintain WDS communication. That is, after AP2 changes from the current channel to the change channel, AP2 detects the radar wave within a predetermined time, and therefore, even if the change channel is changed every time to a new channel again according to the DFS operation, WDS communication can be resumed and maintained.

  As described above with reference to the respective drawings, the radio base station (in particular, the route, the parent device) according to the embodiment performs DFS operation by detecting radar waves in other radio base stations (in particular, repeaters). By responding to the connection request from the adjacent wireless base station (repeater) without switching from the AP mode to the STA mode, it is possible to reduce the time when communication caused by the mode switching can not be performed, and the embodiment can be promptly implemented. WDS communication can be resumed within the communication system related to

  In addition, when the wireless base station (in particular, the route and the parent device) according to the embodiment can not receive the connection request from the adjacent wireless base station (repeater) for a predetermined time after the channel change in the AP mode, However, it is possible to switch to the STA mode, acquire the channel to be changed by scanning itself, perform wireless communication with the AP 2 and resume WDS communication. That is, after changing from the current channel to the change channel by the adjacent wireless base station (repeater), the adjacent wireless base station (repeater) detects the radar wave again within a predetermined time, thereby newly performing the DFS operation. Even if the channel is changed every moment, WDS communication can be resumed and maintained promptly.

  As described above, the wireless base station according to the embodiment (in particular, the route and the parent device) has the DFS operation by the detection of the radar wave even in the environment where the WDS communication is performed in the 5 GHz band channel. , WDS communication can be resumed and maintained promptly.

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

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 any terminal via a plurality of wireless base stations, the wireless base station is directly connected wirelessly with the wireless terminal,
Wireless IF unit for searching other wireless base stations,
A channel notification unit that receives a channel change notification from another wireless base station;
A channel change unit that changes a channel based on the channel change notification information;
A mode switching unit that switches the mode between the access point mode and the station mode;
A communication control unit for notifying the mode switching unit of mode switching when there is no connection request from another wireless base station within a fixed period after receiving the channel change notification;
A wireless base station comprising
The mode switching unit is
After switching to the station mode based on the notification from the communication control unit, the wireless IF unit searches for another wireless base station, and the channel changing unit changes the channel to a channel used by the other wireless base station Then switch to 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 to change the channel based on detection of the radar wave by the other radio base station.
In a wireless communication method 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 a wireless base station directly connected wirelessly with the wireless terminal,
Receiving channel change notifications from other wireless base stations;
Changing the channel based on the channel change notification information;
Switching to the 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;
And searching for another wireless base station, changing the channel used to a channel used by the other wireless base station, and then returning to the access point mode.